08-03-2006 Comparing SBM and HA coated implants - MIREILLE WASSEF THESIS

TABLE OF CONTENTS TABLE OF CONTENT OF FIGURES…………………………ii ACRONYMS………………………………………………………x AKNOWLEDGMENT…………………………………………..xii INTRODUCTION……………………………………………….1 REVIEW OF LITTERATURE………………………………….3 IMPLANTS AND OSSEOINTEGRATION…………...3 IMPLANT SUPPORTED OVERDENTURE AND IMMEDIATE LOADING………….……………………….....24

SUPPORTING STRUCTURE AND IMMEDIATE LOADING. ……………………………………………....32 IMPLANT SURFACES AND IMMEDIATE LOADING………………………………………………..41 METHODS OF EVALUATION………………….……48 AIM OF THE STUDY……………………………………………56 MATERIAL AND METHODS…………………………………..57 RESULTS………………………………………………………….88 DISCUSION………………………………………………………138 SUMMARY AND CONCLUSION……………………………...150 REFERENCES …………………………………………………..152 ARABIC SUMMARY………………………………………………1

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TABLE OF FIGURES Fig (1)

Diagnostic sheet

59

Fig (2)

Curved campus

59

Fig (3)

Radiographic stent with 4 balls 5mm in diameter

62

Fig (4)

Panoramic radiograph with an edentulous upper and 62 lower arch showed 4 balls

Fig (5)

Occlusal Tomogram radiograph showing four balls 63 and thickness of the mandible

Fig (6)

Paragon complete implant for one stage surgical 63 protocol

Fig (7)

Radiographic stent modified anterioly

69

Fig (8)

Intact ridge before incision

69

Fig (9)

Stent in the patient mouth before incision

70

Fig (10a)

Mid crestal incision with releasing vertical incision

70

Fig (10b)

Alveloplasty and surgical stent placement

71

Fig (11)

Marking of the places of the implant osteotomy

71

Fig (12)

Four Osteotomy sites

72

Fig (13)

Paralleling pins inside osteotomy

72

Fig (14)

Paralleling pin between 3 sides across the arch after 73 completion of osteotomy

Fig (15)

Paragon implant insertion

73

Fig (16)

Four Paragon implant insertion with healing caps 74 after insertion

Fig (17)

Soft tissue closure with triple 0 black silk sutures

74

Fig (18)

Hader bar is cut according to the space available

77

Fig (19)

Hader bar fix in place by autopolymerised burnt out 77 acrylic resin (Duralay)

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Fig (20)

Space between bar and tissue

78

Fig (21)

Soldering of the gold bar in the laboratory

78

Fig (22)

Blockage of undercut during clip pick up

79

Fig (23)

Denture fitting surface with the Hader clips

79

Fig (24)

Rinn holder XCP long cone technique

82

Fig(25a,

Radiographic stent for long cone technique long cone

83

b) Fig (26)

Periapical radiograph measured by the Digora 84 software

Fig (27)

Probing depth mid buccal reading

84

Fig (28)

Periotest

85

Fig (29)

Periotest measured the damping of the implants 85 application perpendicular to the abutments

Fig (30)

Periotest screen

86

Fig (31)

Patient one intact ridge

124

Fig (32)

Patient one Final restoration

124

Fig (33)

Patient one preoperative panorama

125

Fig (34)

Patient one preoperative panorama with surgical 125 indicating steel balls

Fig (35)

Patient one, one year follow up

126

Fig (36)

Patient two, intact ridge

127

Fig (37)

Patient two, final restoration

127

Fig (38)

Patient two preoperative panorama

128

Fig (39)

Patient two preoperative panorama with steel balls

128

Fig (40)

Patient two one year follow up

129

Fig (41)

Patient three intact ridge

130

Fig (42)

Patient three final restoration

130

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Fig (43)

Patient three pre operative panorama

131

Fig (44)

Patient three pre operative panorama with steel balls

131

Fig (45)

Patient three post operative panorama

132

Fig (46)

Patient three one year follow up

132

Fig (47)

Patient four preoperative intact ridge

133

Fig (48)

Patient four final restoration

133

Fig (49)

Patient four preoperative panorama

134

Fig (50)

Patient four preoperative panorama with steel balls

134

Fig (51)

Patient four one year follow up

135

Fig (52)

Patient five intact ridge

136

Fig (53)

Patient five final restoration

136

Fig (54)

Patient five preoperative panorama with steel balls

137

Fig (55)

Patient five one year follow up

137

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TABLE OF HISTOGRAMS Histogram 1:

Relationship between the crestal bone height mesial 90 to the implants with the HA and the SBM surfaces

Histogram 2:

Patient one, Relationship between the crestal bone 91 height mesial to the implants with the HA and the SBM surfaces

Histogram 3:

Patient two, Pattern change of the crestal bone 92 height mesial to the implants with the HA and the SBM selective surfaces

Histogram 4:

Patient three, Pattern changes of the crestal bone 93 height mesial to the implants with the HA and the SBM selective surfaces

Histogram 5:

Patient four, Pattern changes of the crestal bone 94 height mesial to the implants with the HA and the SBM selective surfaces

Histogram 6:

Patient five, Pattern changes of the crestal bone 95 height mesial to the implants with the HA and the SBM surfaces

Histogram 7:

Pattern changes in crestal bone height distal to the 97 implants with the HA and SBM surfaces

Histogram 8:

Patient one, Pattern changes of the crestal bone 98 height distal to the implants with the HA and the SBM surfaces.

Histogram 9:

Patient two, Pattern changes of the crestal bone 99 height distal to the implants with the HA and the SBM surfaces

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Histogram 10

Patient three, Pattern changes of the crestal bone 100 height distal to the implants with the HA and the SBM surfaces

Histogram 11

Patient four, Pattern changes of the crestal bone 100 height distal to the implants with the HA and the SBM surfaces

Histogram 12:

Patient five, Relationship between the crestal bone 101 height distal to the implants with the HA and the SBM surfaces

Histogram 13:

Percentage changes of crestal bone height mesial to 103 the implants with HA and SBM selective surfaces

Histogram 14:

Percentage changes of crestal bone height distal to 104 the implants with HA and SBM selective surfaces

Histogram 15:

Periotest value of the implants with the HA and the 106 SBM selective surfaces

Histogram 16:

Patient one, Periotest value of the implants with the 107 HA and the SBM surfaces

Histogram 17:

Patient two, Periotest value of the implants with the 108 HA and the SBM surfaces

Histogram 18

Patient three, Periotest value of the implants with 109 the HA and the SBM surfaces

Histogram 19

Patient four, Periotest value of the implants with the 110 HA and the SBM surfaces

Histogram 20

Patient five, Periotest value of the implants with the 111 HA and the SBM surfaces

Histogram 21

Effect of time on the mean Periotest value (PTV) 113

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for the HA and the SBM selective surface implants Histogram 22:

The Probing depth of the HA and The SBM 115 selective surface media

Histogram 23:

Patient One, The Probing depth of the HA and The 116 SBM selective surface media

Histogram 24

Patient Two, The Probing depth of the HA and The 117 SBM selective surface media

Histogram 25

Patient Three, The Probing depth of the HA and 118 The SBM selective surface media

Histogram 26:

Patient Four, The Probing depth of the HA and The 119 SBM selective surface media

Histogram 27:

Patient Five, The Probing depth of the HA and The 119 SBM selective surface media

Histogram 28:

Correlation of the length of the bar and the crestal 122 bone height selective surfaces

Histogram 29:

Correlation of the Periotest values and the marginal 123 bone changes related to the implants

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TABLE OF RESULT TABLES Table 1:

Pattern Changes of crestal bone height mesial to the 89 implants in Periapical radiograph of the HA and SBM selective surfaces

Table 2:

Pattern Changes of crestal bone height distal to the 96 implants in Periapical radiograph of the HA and SBM selective surfaces

Table 3:

Percentage change of crestal bone height mesial to the 102 implant with HA and SBM selective surfaces

Table 4:

Percentage change of marginal bone height distal to the 104 implant with HA and SBM selective surfaces

Table 5:

Periotest mean value of the HA and the SBM selective 105 surfaces

Table 6:

Effect of time on the mean of the Periotest Value related 112 to the HA selective

Table 7:

Effect of time on the mean of the Periotest Value related 112 to the SBM selective surface

Table 8:

Probing Depth readings comparing the HA and the SBM 114 selective surface media

Table 9:

Effect of time on Probing depth related to the HA 120 selective surface

Table 10:

Effect of time on Probing depth related to the SBM 120 selective surface

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Table 11:

Correlation of the length of the bar and the crestal bone 121 height

Table 12:

Correlation of the Periotest values and the marginal bone 122 changes related to the implants

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ACRONYMS

ACRONYMS Âś

This section includes abbreviations and scientific terminologies mentioned throughout the document ADA:

American Dental Association

A-P:

Anterior Posterior Distance

CCEF: Capacitively Coupled Electric Field CPT:

Commercially Pure Titanium

CTC:

Connective Tissue Contact

DIB:

Distance between the Implant Top & First Implant-to-Bone Contact

DIM:

Distance between the Implant Top & Coronal Gingiva

EDS:

English, Donnel and Staubli Rider System

HA:

Cylindrical Hydroxyapatite Coating Surface

Ha-Ti: Hydroxyapatite Titanium Screw Implants HGB3:

Hader Gold Bar 3mm

HGB5: Hader Gold Bar 5mm IBA:

Ion Beam-Assisted deposition

IMZ:

Intra-Mobile Elements

ITI:

International Technology Institute Group

JE:

Junctional Epithelium

MBI:

Modified Bleeding Index

MPI:

Modified Plaque Index

MTI:

Mini Transitional Implants

PD:

Probing Depth

PRP:

Platelet Rich Plasma

PTV:

Periotest Values

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Ra:

Average Roughness of Sandblasted and Acid-Etched Surfaces

RFA:

Resonance Frequency Analysis

SBM:

Soluble Blasting Media

SD:

Sulcus Depth

SLA:

ITI selective surface Screw Implant

STI:

Spline Twist Implants

TPS:

Titanium Plasma Spray

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ACKNOWLEDGMENT

This work would never been completed without the will of GOD All Mighty. I would thank God for The power that He gave his humble servant to finish this work and for all the people that He put in my way to help me accomplish this success.

I am deeply thankful for DR. Mahmoud El Afandy, Professor and Head of the Prosthodontic Department, Ain Shams University for his unlimited patience and scientific guidance.

I am most grateful to DR. Mona Shoeib, Professor, Department of Oral Medicine and Periodontology, Cairo University for her kind, sincere and scientific supervision all the course of the study.

I would like to express most sincere thanks for DR. Amal Mobarak, Assistant Professor, Prosthodontic Department, Ain Shams University.

For her undivided attention and patience through the course of the study.

I would like also to thank the Head of the Dental Radiology Department for his understanding and his help in accomplishing this study especially the Radiology Technicians, Dental Radiology Department, Ain Shams University for there cooperation and good knowledge specially Mr. Samy Abdel Karim Ahmad, Mr. Essam Mohamed Abdel Aziz, Mrs. Marine Abdel Malak and Mrs. Sana'a Salama.

I am most grateful to all my patients each one by his name for their cooperation understanding and motivation Mr. Abdallah Abdel Razek, Mr. Mohamed Abdel Fattah, Mr. El Sayed Abdel Rahman, Mr. Saeid Abdel Aziz and Mr. Sobhy Abdel Wahab.

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Last but not Least I would like to thanks members of my Family for their unlimited support and understanding especially my husband Ramy and my kids Marc and Tasha. Not to forget my parents their patience and encouragement.

To my reason for living, Marc and Tasha

Without you I would never stand up after every fall.

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INTRODUCTION

Many patients lost their teeth which made them realize the severe problem of complete edentulism. The loss of natural dentition due to caries and/or periodontal diseases along with the loss of neuromuscular coordination is signs of the population aging.1-2 These problems are accompanied by low self esteem, reduction of the person ability for mastication therefore disturbed nutritional status along with other troubles including defective speech and bad aesthetics. The insertion of prosthesis either fixed or removable could be the solution for these problems. Many patients seek solution for there problems and the conventional treatment for these cases is the construction of a complete denture.

For patients wearing dentures for the first time the problem lies in the great expectation of the patient that once wearing the denture expecting the end of the suffering, using artificial teeth like the natural dentition.

Patients usually get disappointed. Before complete comfort to occur it is advised to the patients to accommodate the surrounding musculature for the new prosthesis, which might take up to six weeks for using the denture properly.

The problem of the complete edentulism lies in the resorption of the alveolar process and related problems as the loss of the vertical dimension, the loss of the facial vestibule, the sinking of the lips and cheeks, the prominence of the naso-labial groove that all give the patient the senile look. The goal of modern dentistry is to restore the patient’s mouth to normal contour, function, comfort, aesthetics, speech, and Š2006 Mireille Wassef

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health regardless of the atrophy, disease, or injury of the stomatognathic system.3 In most cases recommended for removable complete dental prostheses, the question of stability and support is present, as in most cases, the complete edentulous ridge is atrophic due to several etiological factors in this case a consideration of the dental implant is viable.

As for the patients satisfaction dental implants supported overdenture is likely to be more comfortable than a conventional dentures.

Implant reconstruction and oral rehabilitation provide the patients with the opportunity to recapture lost masticatory function, rehabilitate esthetic compromised, and achieve a greater sense of well-being.

Thousands of seriously debilitated edentulous mouths have been dramatically rehabilitated using osseointegrated fixtures that maintain fixed and removable appliances. Stable implant supported prostheses could reverse years of denture discomfort and compromised oral function.

The use of dental implants as a method of restoring the function of natural dentition recommended waiting at least three to six months before the application of a functional load; the delayed loading was to promote the healing of the soft tissue as for the osseointegration to occur.

The use of an Immediately loaded Overdenture supported by dental implants minimize all the problems as it gives support for the alveolar ridge and prevents its rapid resorption as well as instant restoration of mastication and aesthetics.

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REVIEW OF LITERATURE

IMPLANTS AND OSSEOINTEGRATION IMPLANT DEFINITION According to the Academy of Prosthodontic 2005 dental implants is defined as “A prosthodontic device of alloplastic material, implanted into the oral tissues beneath the mucosal and or periosteal layers and or within the bone to provide retention and support for fixed or removable prostheses.”4 While the American Dental Association (ADA) organization defined implants as, "Material inserted or grafted into tissue as for dental implants," A device specially designed to be placed surgically within or on the mandibular or maxillary bone as a means of providing for dental replacement; endosteal (endosseous); eposteal (subperiosteal); transosteal (transosseous)."5 IMPLANT HISTORY Replacing the missing parts of the body started as humanity itself. Lost teeth anchored by devices in the bone were discovered by archeologists in ancient civilizations. The ancient Egyptian and the South American civilization experimented the replacement of lost teeth with Hand-shaped ivory or wood substitutes. 6-7 In the 18th century lost teeth were replaced with extracted teeth of other human donors but the procedure was not so successful due to the strong immune reaction of the receiving individuals as well as the

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awareness of the individuals of there human rights and the transmission of disease after the implantation.6-8-9 In 1809, Maggiolo fabricated a gold implant which was placed into fresh extracted socket and was attached to a tooth after an appropriate healing period. In 1887, a physician named Harris tried the same with a platinum post. In 1886 Edmunds was the first in the United State (US) to implant a platinum disc into jaw bone and then a porcelain crown was placed on top of it but still the long term success was very poor. 6-10 Strock placed the first successful oral implants in 1937 at Harvard University using a vitallium implant in bone immediately after tooth extraction and it shows successful results. 6-9 From the mid 1930 evolved several implant concepts as subperiosteal implant first placed by Gustav Dahl in 1948, Endosteal Blade Implant introduced by Leonard Linkow and Ralph and Harold Roberts in 1967. 611

It was till 1952 that dental implant produced a major leap when Per Inguar Branemark an orthopedic surgeon in the university of Lund, Sweden, experimented the fusion of titanium cylinder into the thigh bone of a rabbit and called this phenomena “Osseointegration” several researches followed and it was not until 1981 enough data to Branemark and his team to publish landmark paper for the doubts of scientific community. 6-12 MATERIAL USED IN DENTAL IMPLANTS

METALS It is the most common material used in the field of dental implants.

Commercially pure titanium CPT is the most successful metal that can be ©2006 Mireille Wassef

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used due to its inert property on the surrounding tissues. Due to its sensitivity towards the inclusion of oxygen, its difficult manufacture and its very low density some manufactures used the titanium alloys as Titanium/ Vanadium/ Aluminum which have more suitable properties.13 Stainless steel, and cobalt /chromium /molybdenum alloys were used for implant construction but had been discarded because of its corrosion products and its unfavorable response to bone.14 CERAMICS Carbon and ceramic have been used in the field due to there inert property, biocompatibility, high strength, and physical property as color, minimal thermal and electrical conductivity; however its brittleness and low ductility made its use limited. 15 High ceramic from aluminum, zirconium and titanium oxides had been used as dental implants due to its clear white cream or light grey color that is very beneficial for use in the anterior region for aesthetic reason.15 The manufacturers of ceramic tried to mimic the bone structure in ratio and crystalline particle of calcium and phosphorus thus resulted the synthetic Hydroxyapatite.16 In the ceramic group the aluminum oxides as alumina and sapphire although stronger than metals tends to be more brittle. Similar to ceramic is the carbon based material as pyrolytic carbon, polycrystalline carbon (vitreous) and carbon/silicon interstitial combinations. Ceramic and carbon has first been introduced as coating on metallic substrates.16 POLYMERS Polymers have not proven success in implant fabrication due to its problems of obtaining integration which is essential in endosseous Š2006 Mireille Wassef

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implant success. Their application is limited to components of some implant systems where their physical properties are useful and the tissue responses are appropriate. Example of their use, is the elastomeric sealing “O” ring on the abutment screw of a Branemark implants polymeric healing caps and the “Elastic” Intra-Mobile elements of the IMZ implant system.14 SURFACES AND COATINGS OF DENTAL IMPLANT

SMOOTH SURFACE Manufacture machined smooth commercially pure titanium surface.

The smooth part constitutes the part where the implant is contacting the bone also called the implant/bone interface. Machined implants are lathe cut, finished and ultrasonically polished. For many years it was thought that the machined surface implants were ideal for long term Osseointegration. 17 ROUGHED SURFACE, Increase the surface area of the dental implants in the implants/bone interface was a goal; to increase the contact area and to enhance the osseointegration.18 Many ways were introduced to increase the surface area as well as roughening as, Titanium Plasma Spray (TPS), Hydroxyapatite (HA) coatings, acid etched and Sandblasted. 19 The titanium plasma sprayed TPS surface originated by ITI is characterized by high velocity molten drops of metal being welded to the implant body. Hydroxyapatite coating is applied to the implant body surface by the same TPS technology.19-20 Hydroxyapatite Plasma Spray (HA) was developed as an implant surface coating by de Groot in 198021 but did not become commercially ©2006 Mireille Wassef

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available until approximately 1985. 22 Numerous studies had reported superior biocompatibility and long term effectiveness of HA-coated dental implants.23-24 HA has been documented to bioactively stimulate a much more rapid attachment of bone than uncoated titanium surfaces of various textures,

23-25-116

to form a stronger bond and to achieve a greater

percentage of bone contact than uncoated titanium surfaces.26 Techniques had been progressed to control the surface characteristics.

Sintering and coating the spherical titanium powder with agents, such as nitric acid, hydrofluoric acid, hydrochloric acid, and sulphuric acid, and/or air abraded or particulate-blasted with aluminum oxide, tricalcium phosphate, or titanium dioxide was used. These particles might be of different sizes, either singularly or in combination, to obtain a controlled surface texture that enhance cellular activity and bone to implant contact.27-28 Roughening the implant surface by grit blasting has also been widely used to increase implant surface area. The original Core-Vent implant featured a moderately rough, titanium alloy (Ti- 6Al-4V) surface created by grit blasting with aluminum oxide (Al2O3), followed by passivating in nitric and sulfuric acids.29 When blasted with a non-soluble material, such as Al2O3, particles of the blasting medium can become embedded in the metal and contaminate the implant surface. Blasting the implant surface with a soluble blasting medium (SBM™) provides the opportunity for dissolution of embedded particles during the washing cycles that follow the blasting procedure. The SBM body blasted with soluble tricalcium phosphate has shown greater bone attachment than with machined or acid-etched surfaces.120-123 Above the blasted surface and the HA coating is machined neck (smooth surface) designed for maintenance of soft tissue hygiene.30 Š2006 Mireille Wassef

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Paragon implants with a SBM surface have acid etched apical (2.5-mm extension) and coronal (1.5- mm extension) extremities, and the rest of the implant is blasted with tricalcium phosphate subsequently removed with nitric acid. According to the manufacturer, this treatment produces a surface that is twice or three times rougher than the machined surface.120 Buser et al31 compared six different implant surfaces and concluded that the extent of bone-implant interface is positively correlated with an increasing roughness of the implant surface.

Kim et al

32

proved that the percentage of bone to implant contact for

the oxidized implant is greater than that of the blasted implant only in the first four weeks and there is no statistical significance after twelve month period as well as there is no statistical significance regarding the percentage of bone area inside the threads of the two groups between four and twelve month.

Schneider et al33 noticed that there are changes in gene expression of the osteoblasts made by the surface characteristic of the implant. This is significant to both the mineralization and the cell attachment. The cell proliferation remains the same in titanium Commercially Pure (CP), grooved, and rough surface characteristic.

Recently in surface technology the combination of two or more surface characteristics improve both the soft tissue and bone response.

One design might incorporates the four different surface textures on the same implant body etched, grit-blasted, HA or TPS and an etched apical tip.19 LASER INDUCED SURFACE ROUGHENING The use of laser in producing the surface roughening is much precised as it locates the specific area to be applied with predetermined Š2006 Mireille Wassef

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angulations creating regular micro retentions rather than non oriented roughness created by the TPS or sandblasted techniques.34 SURGICAL TECHNIQUES IN DENTAL IMPLANTS

ONE STAGE SURGICAL PROTOCOL This technique does not include the reopening of the surgical site at the prosthetic stage. Dental implants used are non-submerged dental implants. 35 TWO STAGE SURGICAL PROTOCOL It is first introduce by Branemark at the years of the early 60s and include the complete submerging of the dental implant for a proper healing period 3-4 months in the mandible and up to six months in the maxilla. The second stage of the surgery is to uncover the imbedded implant and to start the prosthetic procedure. In the original protocol, studies have advocated a two-stage surgical protocol for load-free and submerged healing to ensure predictable osseointegration. The technique the most used in clinical practice and its success rate is up to 98%.36 OSSEOINTEGRATION Zarb and Albrektsson, defined in 1991 Osseointegration: “Osseointegration is a process whereby clinically asymptomatic rigid fixation of alloplastic materials is achieved and maintained in bone during function.”37 According to the Glossary of dental implants osseointegration is defined as “The procedure by which a contact is established without interposition of non-bone tissue between normal remodeled bone and an

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implant entailing a sustained transfer and distribution of load from the implant to and within the bone tissue."38 FIBROUS INTEGRATION (LIGAMENTOUS INTEGRATION) Healthy dense collagenous tissue between implant and bone.31 the fibrous integration was also called “Osteopreservation” in which around the healing functioning endosteal implant a ligament is formed of osteostimulatory collagen fibers that diminish the load on the bone, hence preserving the alveolar ridge. This form of integration is present in the blade\plate form modality.39 FIBRO-OSSEOUS INTEGRATION The tissue to implant contact comprises both bone and fibrous tissue contact.39 Linkow et al40 classified histologically the contact between the bone/implant interface by percentage of contact into; fibrous integration, when the layer of fibrous or collagenous tissue interspersed between implant and bone is less than 125 microns(µ); fibro-osseous integration, when there is a combination of thinly defined fibrous connection with 22% or less direct bone contact with the implant; and osseous integration, when there is 23% or more direct bone-to-implant contact, with no evidence of fibrous connective tissue anywhere.

PERIOSTEAL INTEGRATION It is the mode of tissue integration around a healing functioning subperiosteal implant. The prime load-bearing tissue at the interface is a sheath of dense collagenous tissue constituting the outer layer of the periostium. This sheath diminishes the functional force passed to the underlying cortical surfaces of basal bone. 39 ©2006 Mireille Wassef

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FACTORS AFFECTING THE SUCCESS OF OSSEOUS-INTEGRATION There are some factors affecting the long term success of osseointegrated dental implant.37-41-42-43 IMPLANT RELATED FACTORS

Implant Biocompatibility The material of the implant is the main factor of implant biocompatibility. The corrosion resistance that the material can withstand ensures good biocompatibility.37 The commercially pure CP Titanium ensure good adherence to bone due to its firm oxide layer. Titanium alloy such as ti-6Al4Va may show less biocompatibility because the leach out of the alloy’s components. 37 Implant design Researchers performed tests on the implant design regarding cylindrical or screw type implants. Results had shown the insignificant statistical differences between designs as regard osseointegration.44 Implant surface The

presence

of

surface

roughness

ensure

better

osseointegration as it increases the surface area in which the bone is in contact with the dental implant.45 The surface quality depends on the physical, chemical, mechanical and topographic properties of the surface which might work together to influence the functional activity of the cells; the change in the implant topography will result in change Š2006 Mireille Wassef

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in the surface energy, thickness of oxide layer, that leads to change in the chemical composition of the surface of the implants. Some methods used to alter the surface topography include electropolishing, grinding, abrasive blasting, plasma spraying,

photolithography,

and

laser

induced

surface

roughnening.37 Surface coatings had been introduced to the titanium surface such as titanium plasma coating TPS or calcium phosphate coating. The use of metal alone increases the risk of dissolution of metal ions and the formation of inorganic material which may decrease its biocompatibility compared to the bio-ceramic materials. Hydroxyapatite has the same inorganic component of bone and displays some bioactive chemical adhesion to the surrounding bone. The surface coatings could be protected from leaching out of the metal surface by techniques that have been introduced to increase their adhesion property such as Ion BeamAssisted Deposition.46 HOST RELATED FACTORS

State of the Host Bed The most desirable bone bed is a healthy and with sufficient bone stock. There are few diseases and conditions of bone that alter the bone quality and sometime make it contraindicated to proceed with an implant treatment. Radiation is one of the conditions that jeopardize implant placement; it is not the radiation itself; but the condition of the capillary bed after the radiation, which may decrease the percentage of healing.

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Hyperbaric oxygen is used to increase the oxygen concentration in bone and then may increase the repair power.37 Osteoporosis is also one of the conditions of the bone bed that might be considered. This condition is not affecting the whole body in general. It may only affect some parts of the body47.

To increase the bone bed and enhance osseointegration several researches were performed using capacitively coupled electric field (CCEF) to enhance osteogensis some suggested its use in bone disease and delayed bone repair.48 Shigino et al. 49-50reported that by histological and radiological assessment in dogs the CCEF appears to increase bone area but not necessary bone implant contact which appears to promote osteogensis and decrease the period needed for osseointegration to occur. Thus promote the formation of dense bone near implant and enhance the early occlusal loading.

Schlegel et al. 51conducted a study on pigs using different ways to enhance osseointegration by conditioning the bone bed by osteoinductive collagen, platelet rich plasma (PRP), and the use of bone condensation. Therefore it could be useful to use these methods where the bone bed is affected with disease or treatment modality that decreases the proper regeneration.

The use of bone augmentation and bone grafting was also discussed in the literature to increase the capacity of the bone bed in case of severe bone resorption or destructive disease. 37

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SURGICAL

TECHNIQUE RELATED FACTORS

The surgical technique The surgical technique could be very sensitive for implant success or failure. Heat generation and manipulation could cause the death of the osteoblasts. Appropriate drilling speed with sharp drills and irrigation internal or external dissipate heat generation. It had been reported in several studies that the drilling speed for preparing an implant site at 2500 rpm could decrease the risk of osseous damage, which may affect the initial healing of dental implants.37-52-53 The clinical benefit of using the more expensive internal irrigation systems is unjustifiable, as it did not appear to reduce the thermal challenge to the bone over the simple flood irrigation.37-54 Bone tissue is more sensitive to heat than previously believed.

56 degree centigrade (ºC) was the range of temperature by which the denaturation of the alkaline phosphatase enzyme begins.

Nowadays the time\temperature relationship is the concerning parameter. Bone necrosis believed to happen at the range of 47ºC\one minute. Another parameter of concern is the implant insertion torque. The increase of torque will result in bone tension subsequent resorption therefore a moderate power is required.37 Post surgical Loading related factors It was recorded that the proper healing period for the mandible is three to four months and in the maxilla four to six months ©2006 Mireille Wassef

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according to the site and type of bone before applying any functional load on the dental implant. Premature loading will lead to soft tissue anchorage and poor long term function while the use of gradual load will ensure longetivity of the procedure.55 The immediate loading had been always a controversy between authors in the literature.56-57 IMMEDIATE LOADING In the year 1963 Leonard Linkow58 was the first to introduce the idea of endosseous implants immediate loading. He studied the effect of immediate loading a self-tapping endosseous root form implant known as Ventplant with overdenture or acrylic provisional fixed bridges.

59

This

protocol was also conducted in the same year on the implant aiguille (needle implants) followed with subperiosteal implant immediate loading in 1964. 60 In 1967 the endosseous blade implant was also suggested to be immediately loaded for splinting purposes. It was believed that the surgical technique was responsible for local osteolysis.61 -62 SUCCESS RATE OF IMMEDIATE LOADING Herrera-Briones et al.63 reviewed the immediate loading attempts from the seventies till our present time.

In 1979 Ledermann64 loaded 476 TPS implants in 138 patients; he obtained a percentage of success of 91.2%. In 1983, Schroeder et al65 compared immediate and delayed loading using TPS implants with a follow up of 48 month for delayed and 17 month of immediate loading.

Four of the implants were immediately loaded and 53 delayed and he

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obtained a success rate of 100% of the immediate and 98.1% of delayed loading.

In 1985, Thomas and Cook66 studied the effect of implant surface texture along with twelve variables in immediate loading protocol. Twelve types of implants were evaluated in vivo by placement transcortically in the femora of adult mongrel dogs for a period of 32 weeks. The results showed that undecalcified histologic evaluation of the implants demonstrated that the roughened implants exhibited direct bone apposition.

In 1986 Babbush et al.67 immediately loaded 514 implants for 129 patients. Each patient received four TPS implants between the two mental foramina; these implants were soldered together by Dolder bar and supported a mandibular overdenture. The success rate of the implants was 96.1%.

However, in 1990 Schnitman et al.68 received lesser percentage of success than Babbush et al.67, using Branemark implants. They compared the effect 28 implants immediately loaded in relation with 35 delayed loading implants. The success rate was 85.7% for immediate and 100% for delayed. They concluded with agreement with Thomas and Cook66 that the quality of bone was more important than implant length for implant survival.

It was rather believed that the loading of the implants immediately will lead to a fibrous-integration rather than osseointegration due to the interruption that load produces during bone healing that may lead to proliferation of fibroblast instead of osteoblast.56-69

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Further more it was believed that the implant should be submerged to prevent infection and epithelial down growth and to minimize early implant loading during bone remodeling.55 Micromotion of the implant bone interface may result from functional overload and may disturb the early remodeling phase of dental implants in bone.70 Micromotion can cause fibrous repair at the interface rather than osseous regeneration and osseointegration.55 It is not micromotion per se that must be considered in implant osseointegration but also the threshold of acceptable micromotion.

Cameron and colleagues71 hypothesized that micromotion at the bone implant interface can be tolerated below a certain threshold and this was confirmed by several authors.72-73 These studies demonstrated that micromotion up to 150 µm should be considered excessive and harmful for osseointegration on the other hand micromotion less that 50 µm seems to be tolerated. So the critical range seems to lie between 50 and 150 µm and this depends on implant morphology and surface.72-73 Brunski74 stated that 100 µm of micromovement may be critical to boneimplant healing and this may lead to fibrous integration.

In the presence of good soft tissue seal without epithelial integration or infection and elimination of the micromotion related to the implant bone interface, the immediate loading concept protocol could obtain a higher degree of success.75 Salama et al.76 summarized some guidelines for the immediate loading protocol;

The bone quality in which the implant is going to be

loaded should be appropriate that explains the higher rate of

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immediate loading procedure in the mandible more than the maxilla.

The implant should engage strong cortical bone with

initial stability.

The type of implant should be screw type with rough

surface preference promoting osseointegration.

Implants should be tripoded, bilaterally splinted and

distributed over as wider area as possible.

Cantilever should be avoided.

Provisional restoration should be fabricated form rigid

connection to prevent flexure.

An occlusal scheme that promotes axial loading rather

than horizontal stress must be designed.

With parafunctional habits, night guard should be

fabricated although it is not preferred that a patient with parafunctional problems subjected to immediate loading.

Several researches were conducted to prove the success of immediate loading according to numerous protocols. Wolfinger et al.77 compared two different protocols, the developmental and the simplified protocol.

The developmental protocol did not exclude patients with history of parafunctional habits, diabetes, and malocclusion, hypertension, past history of angina or even aortic aneurism. The patients were not selected with special criteria and the implants were placed anterior and/or posterior. The immediately loaded provisional restoration was removed from seven to ten days after surgery for the easiness of suture removal and after six weeks to be replaced with metal reinforced prostheses. After ©2006 Mireille Wassef

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the follow up of five years the prosthetic survival of this protocol was 100% although for the immediately loaded implants the survival rate was 80 %. The low success rate was multifactorial. The cause suggested might be due to patient selection, mandibular deflexion especially for the posterior failure and the interruption of prosthetic removal and insertion that might have caused micromotion.

The simplified protocol was based on the experience of the developmental group the major change in the new protocol was not to disturb the acrylic resin provisional prostheses for three months the survival rate of the implants was 97% for the immediately loaded ones.

As a conclusion from both protocols is to maintain the initial implant splinting over a healing period of approximately three months and that implant placement between the mental foramina provides optimal support due to absence of specific exclusion criteria. For patients used in this study the results in this investigation population suggested that diabetics and bruxers may be at increased risk of implant failure in the immediate loading procedure.

Chiapasco78 reviewed some of the researches performed on Immediate Loading and concluded: ƒ

Good bone quality, primary implant stability and

splinting of implants in case of immediate and early loading are recommended. ƒ

Immediate loading of full arch mandibular fixed

prostheses and overdentures supported by rigidly connected implants between the mental foramina could be routinely performed and has a base of clinical evidence.

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Early loading of implants placed in the mandible with

fixed prostheses or overdenture seems to be reliable procedure.

IMMEDIATE LOADING TERMINOLOGY IMMEDIATE OCCLUSAL LOADING It is the loading by implant prosthesis within two weeks of implants insertion. 79-80 EARLY LOADING The occlusal load of the implant prosthesis has to be between two weeks and three months after implant placement.79-80 NON FUNCTIONAL IMMEDIATE RESTORATION The implant prosthesis in a patient who is partially edentulous delivered within two weeks of implant insertion with no direct occlusal load. 79-80 NON FUNCTIONAL EARLY RESTORATION The implant restoration delivered to patient who is partially edentulous between two weeks and three months after implant insertion. 79-80 DELAYED OR STAGED OCCLUSAL LOADING The occlusal loading to an implant restoration is after a period of more than three months after implant insertion. 79-80 TWO STAGE DELAYED OCCLUSAL LOADING The soft tissue covers the implant after initial placement. A second stage surgery after three months exposes the implant to the oral environment. 79-80

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ONE STAGE DELAYED OCCLUSAL LOADING The implant is positioned slightly above the soft tissue during the initial implant placement. The implant is restored into occlusal load after more than three months. 79-80 TYPES OF IMMEDIATE LOADING SUGGESTED PROSTHESES: SINGLE TOOTH RESTORATION, This type of prosthesis has a high risk of failure of 5% in the first year.79 The condition of the hard and soft tissue should be ideal and the implant size should completely seal the socket and yet be away from adjacent teeth or too facial in position. The single tooth replacement should follow some guidelines for immediate loading; 79-80 The tooth should be in the aesthetic zone, no occlusion on transitional restoration, screw shape implants body, more than 12mm long engage cortical bone at apex whenever is possible, soft diet required after surgery and cement the transitional restoration with definitive cement or screw retain. It is contraindicated to patients with parafunctional habits that load the transitional restoration. 79-80 PARTIALLY EDENTULOUS, MULTIPLE ADJACENT TEETH It starts with two or more missing teeth. There are certain outlines to be followed; The site of the missing teeth should be in the aesthetic zone, the number of the implant should be one implant to each tooth, the implant size should be at least 10mm long and four mm wide whenever possible, the implant design should be a screw type, rough surface is preferred for implant, no occlusal contact for at least 2 to 3 months to Š2006 Mireille Wassef

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decrease the parafunctional overload, contraindicated to use cantilever, soft diet preferred to be used and no gum or pencil chewing or tongue trust (parafunctional habits) be permitted. 79-80 FIXED RESTORATION IN COMPLETELY EDENTULOUS PATIENT The patient should have adequate bone in the mandible and at least one implant in the bilateral posterior area should be used and another in the anterior area. To reduce the biomechanical overload; five implants or more have to support the immediate restoration. This procedure is agreed to be of low benefit-risk procedure. Most reports indicated at least eight screw-type implants of 10mm long to be used and two of these implants should be in bilateral molar position and two in the canine region. Few guidelines have to be followed for completely edentulous fixed prostheses; 79-80 Surface area factors ƒ

Eight or more splinted implants for the completely

edentulous maxillary arch and five or more splinted implants for the mandible, more implants if the bone is poor in quality or force factor is great as crown height or mild to moderate parafunction.79-80 ƒ

The size of the implant should be at least 10mm long and

4 mm wide. The larger diameter is needed at the posterior molar regions if

this is not possible; greater implant number is

suggested as to say two implants for each molar, threaded and rough implants should be used. 79-80

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Force factors

Patient with mild to moderate parafunctional habits and

muscular dynamics require more implants. 79-80

In the completely edentulous maxilla anterior implants

should be at least in the bilateral canine position and posterior implants in the first to second molar position. In the mandible at least one implant in the anterior section and one in each posterior region is necessary. 79-80

Occlusal contact should be only in anterior occlusion in

the transitional restoration as to say in the first and the second bicuspid. 79-80

Cantilever

is

not

preferred

especially

posterior

cantilever.79-80

The occlusal load direction performed by narrowing the

occlusal tables and eliminating posterior offset loads on the transitional restoration and directing it to the long axis of the implant bodies whenever possible. 79-80 OVERDENTURES Overdenture is defined as “Removable partial denture or complete denture that covers and rests on one or more remaining natural teeth, the roots of natural teeth, and/or dental implants.”4 OVERDENTURE PROSTHESIS, The totally edentulous patients restored with overdenture are at low risk of occlusal overload for the immediate loading protocol the guidelines needed for this kind of restoration; completely edentulous ©2006 Mireille Wassef

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mandible, abundant to moderate bone height and width, prosthetic space more than12 mm (Interarch distance), opposing maxillary denture, at least four implants inserted between the mental foramina, screw type implants more than10 mm long and at least four mm wide at the crest module, when possible the implants should engage the opposing cortical plate, splint implants together with a bar or a fixed bridge, minimum cantilever on bar (not more than 1 x Anterior posterior spread (A-P) distance), severe bruxism is contraindicated. 79-80

IMPLANT SUPPORTED OVERDENTURE AND IMMEDIATE LOADING

ADVANTAGES OF IMPLANT SUPPORTED OVERDENTURES:

Within the first year after tooth extraction there is an

average of four mm of vertical bone loss in the crest of the ridge.81 With the placement of implants supported overdenture there is a minimal of residual bone loss of 0.6 mm vertical resorption over 5 years so overdentures prevent bone loss.56-82-83

Overdentures provide improved support for the lips and

soft tissues of the face compared with a fixed prosthesis. Also provide stability of the prosthesis and the retention increase due to the presence of attachments that reduces the extent of the overdenture flanges.82

The patient is able to reproduce centric occluding

relation.84 And also the chewing efficiency with overdentures compared with normal denture is improved by 20%,85 and with implant supported prosthesis the maximum occlusal forces is improved by 300%.86

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The movement of an overdenture is decreased during

mandibular movement thus increasing the speech ability of the patient. 82

Regions where severe bone resorption is present can be

compensated with denture flanges rather than bone grafting. 82

Overdentures require less specific implant placement

compared to fixed restorations. The number of supporting implant may be reduced because the soft tissue support. 82

The prosthesis requires maintenance at home, better

prognosis than fixed restorations. 82

The prosthesis is removed by the patient at night giving a

chance for the tissues and the supporting structure to relax and prevent nocturnal parafunctional stresses on the implant. 82

Easy to maintain and to repair. 82

Require shorter appointments and reduce laboratory fees

and fewer implants which reduce overall fees. 82 DISADVANTAGE OF IMPLANT SUPPORTED OVERDENTURES:

It is not usually preferred from the patient as they always

expect a fixed restoration. 82

The absence of adequate Interarch space. The mandibular

overdenture treatment plane requires 12 mm of Interarch distance to provide enough thickness of the acrylic denture base to resist against fracture and to have enough space for the setting of the acrylic teeth. 82

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OVERDENTURE ATTACHMENTS: According to the journal of prosthetic dentistry4 attachments are: "Mechanical devices for the fixation, retention, and stabilization of a prosthesis, a retainer consisting of a metal receptacle and a closely fitting part; the former, the female (matrix) component, is usually contained within the normal or expanded contours of the crown of the abutment tooth or implant and the latter, the male (patrix) component, is attached to a pontic or the denture framework."

Bar attachments Bar systems may be utilized for overdentures, removable partial dentures, and implant prosthesis. Bars may be rigid or resilient, permitting free movement of the prosthesis to direct forces away from the retaining abutments to the supporting bone and tissue. Bar systems are generally in one of three types:

Prefabricated ‘Dolder’ type

Plastic ‘Hader’ type

Round ‘Clip" bars and riders

The Preci (Dolder) Bar The Preci (Dolder) Bar is produced in a precious palladium alloy which is stronger, less expensive, and has a higher fusing temperature than the traditional yellow alloys or as a plastic wax casting pattern. The bar and sleeve attachment are used for retaining removable partial dentures and overdentures. The pear or oval shape is used for a resilient prosthesis providing vertical or rotational movements. The ‘U’ shape is for a rigid, or non- resilient, prosthesis.87

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Hader bar and Clip The Hader bar and rider system was developed by Helmet Hader in 1960.88 Then English, Donnel, and Staubli modified the system in 1992 to form the Hader EDS system. 82 The Hader bar is a semi-resilient system that employs an individual custom-made bar with retentive sleeves that fit into an opposing prosthesis.87 The clip rotation compensates the resiliency of the tissues. The height of a Hader bar system may be as low as 4mm unlike the O-ring system which requires 7 mm so less clearance is required under the denture. 82 The round "Clip" bars and riders, A round bar is useful in situations where the bar must be bent to accommodate the ridge anatomy. 87 OVERDENTURES AND IMMEDIATE LOADING Over the years immediate loading have been successful with overdenture as it utilised many ways for the support and stability, by this, it minimised the micromovement that may hinder osseointegration.70-71 Chiapasco et al.89 Conducted a multicenter retrospective study on 226 patients with implant supported overdenture in the lower jaw, 904 osseointegrated implants inserted in the interforamina area of the mental symphesis and using three different systems ITI and TPS screw implants (Straumann Institute), NLS screw implants (Friatec), and Ha-Ti screw implants (Mathys Dental Implants). A “U” shaped gold bar was fabricated and immediately loaded with and implants retained overdenture. 194 patients followed from minimum of two years to a

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maximum of thirteen years, 32 patients dropped out during the follow up.

Implant failure was of 3.1%, and the bar failure was of 1.5%. This study showed that the success rate of immediate loaded implants is similar to that obtained in the case of delayed loading after osseointegration has taken place.

El Attar et al.90 conducted a study to improve the patient satisfaction during the healing period by using mini transitional implants MTIs and immediately loaded with a temporary denture during the healing period only two of 24 implants showed mobility after three months of implant loading. The results indicated that the MTIs implants integrated sufficiently with bone and permitting proper mucosal healing. After loading the final bone loss around the implants was not significant.

Bohsoli et al.91 used Modular transitional implants to stabilise a maxillary overdenture during the healing period of the submerged dental implants for six months. The histomorphometric analysis of one of these implants and its surrounding osseous tissue showed a 45% bone to implant interface after six months of functional loading. That indicates osseointegration of the transitional implants.

Gatti et al.92 conducted a prospective study in which 21 patients received a mandibular implant supported overdenture and 84 ITI screw implants were placed in the interforamina area of the mental symphesis in which each patient received four implants. A "U" shaped Gold bar was fabricated to splint the implants together as well as to hold the prosthesis.

Patients were followed up from 25 months till 60 months only 2 patients dropped out of the study. After this period of follow up all the implants, bar, and prostheses remained in function.

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Chiapasco et al.93 conducted a study to compare the delayed and immediate loading using Branemark System MKII Implants for 10 patients receiving 40 implants four in the interforamina area of the mandible, rigidly connected with a bar and immediately loaded. The implants were followed up to 24 months and evaluated by means of modified Plaque Index (MPI), modified Bleeding Index (MBI), probing depth (PD), and Periotest. Periimplant bone resorption was evaluated by means of panoramic radiographs taken 12 and 24 months after prosthetic loading. There were no significant differences between two groups. The results from this study showed that immediate loading of endosseous implants osseointegrated as delayed loading.

Ibanez and Jalbout94 conducted a study on the immediate loading of osseotite implants with a follow up of 2 years using 11 patients treated with 87 screw shaped endosteal acid etched osseotite implants (3I). Two mandibular and two maxillary patients received screw retained provisional restorations the day of the surgery. Three mandibular and four maxillary cases were loaded 48 hours after surgery with the final screw retained porcelain fused to metal prostheses. All implant were followed for 2 to 3 years evaluations of the cases were conducted by means of radiographic evaluation. All implants were successful; there was neither implant mobility nor radiolucency around the implants. As a conclusion a high success rate can be achieved when implants with a hybrid surface machined \acid etched are immediately loaded within 48 hours after surgical placements in the maxilla and the mandible.

Romeo et al.95 studied the effect of immediate and delayed loading on ITI implants splinted together by a "U" shaped Dolder bar retaining a mandibular overdenture. They conducted the study on twenty patients divided into two groups. The implants were inserted in the interforamina Š2006 Mireille Wassef

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region in the mental symphesis for both groups. The minimum follow up was two years with recall appointments at two weeks one, three, six, months and one year and every following year. The evaluation was by means of MPI, MBI, PD, Periotest and radiography. Failure occurred with only one implants from the group of delayed loading and no failures from the immediately loaded group. The study concluded that there are no significant differences between both modalities although the immediate loading shortens dramatically the time and more satisfactory to the patients.

Gatti and Chiapasco96 compared the immediate loading of two types of implants using conical transmucosal and standard MKII implants with and mandibular overdenture. They conducted the pilot study with two groups each of them comprised 5 patients with 4 implants each inserted between the mental foramina. After 24 months of follow up evaluation was performed by means of MPI, MBI, PD and radiographic evaluation at 12 and 24 months this type of implants showed 100% success rate.

Lorenzoni et al.97 compared immediate loading and non loading of Frialit-2 for a follow up of six months. 14 implants were loaded at the time of surgery and 28 were not loaded and taken as a control group; the results were evaluated according to the clinical stability of the implants (Periotest Value), and on changes of bone level six months after insertion.

Seven Patients with edentulous mandible following the

immediate loading protocol were treated with 43 implants inserted in the interforamina area, six implants per patient. Two implants of the six implants were chosen to be immediately loaded by a Dolder-bar retained overdenture. After six month second stage surgery was performed and uncovering of the submerged implant revealed bone resorption around the immediately loaded implants more than the unloaded implants. Š2006 Mireille Wassef

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Periotest Values also revealed difference in readings in favour of the unloaded implants. The author related these results to the short evaluation period.

Chiapasco and Gatti98 conducted a study comparing 4 different implant systems(164 Ha-Ti, Mathys Dental; 84 ITI Dental Implant System; 40 Branemark Conical, Nobel Biocare; 40 Frialoc, Friatec. ) for the long term (3-9 years) the survival and success rate of immediate loading using 328 implants inserted in 296 patients. The patients were followed from 36 months to 96 months with a mean follow up to 62 months; six implants were lost due to failure of osseointegration and 18 implants although osseointegrated did not fulfil the success criteria due to bone resorption more than 0.2mm/year after the first year of loading. Each patient received four implants inserted in the mental symphesis and splinted together by a "U" shaped gold bar. The absolute success and survival rates were 91.6% and 97.6% for this study. After a follow up of 7-8 years of ITI and Ha-Ti systems results showed a success rate and survival of 90.4% and 88.8% respectively in comparison with other treatment modality as delayed loading. Nevertheless this decrease is only related to two implant systems. The other implants did not have so much history in literature to be compared to.

Stricker et al.99 conducted a study of ITI implants with bar connected overdenture in the edentulous mandible. Ten patients were received two implants (SLA surfaces and ITI solid-screw) in the interforamina region, and attached with a bar supporting the overdenture, one day after the implants placement. Marginal bone resorption evaluated by periapical radiographs, gingival health by bleeding index and patient satisfaction measured with a visual analogue scale from 1 very bad to 10 excellent.

After 24 months of implant insertion none of them had failed; the Š2006 Mireille Wassef

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average of bone resorption was 0,71mm after 12 months, 92% of the sites had a bleeding index of 0. After 24 months the average bone resorption was 0.08mm. The study proved the success of immediate loading of two implants connected by a bar supporting an overdenture in the interforamina area of the mandible with the use of roughened surfaces implants.

SUPPORTING STRUCTURE AND IMMEDIATE LOADING SUPPORTING STRUCTURE (BONE)

Misch 100 classified the bone according to availability (quantity of bone) to: DIVISION A Abundant bone present soon after extraction in width and in height it may decrease after the first two years of extraction by about 30%.101 The width of this division should be more than 5mm, the height more than 10-13mm, the length more than 7mm. The angulation of load for this division should not exceed 30 degrees between the occlusal plane and the implant body; the crown implant ratio should be less than 1 to counter act lateral occlusal forces.100 DIVISION B Barely sufficient bone the width of the bone is between 2.5-5mm and the height availability remains at 10mm. The resorption of bone produced in the facial aspect of the cortical bone rather than the lingual and the later would be more thick specially in the maxilla.85 The length of bone is more than 12mm and the degree of angulation should be less than 20 degrees and crown/implant ratio less than 1. 100

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DIVISION C Compromised bone; it is deficient in one or more dimensions the width may be less than 2.5mm the height less than 10mm. The crown/implant ratio equals to, or greater than 1 and/or the angulation greater than 30 degree. 100 DIVISION D Deficient bone; long term bone resorption that results in total loss of the alveolar process accompanied by basal bone atrophy. This results in a flat maxilla and pencil thin mandible and the crown/implant ratio may exceed 5 which is a significant force hindering the long term success of any kind of restoration. 100

According to the density of bone (Quality of Bone): Linkow classified bone density into 3 categories:102-103

CLASS I BONE STRUCTURE

The ideal bone type consists of evenly spaced trabeculae with small cancellated spaces.

CLASS II BONE STRUCTURE

The bone has slightly larger cancellated spaces with less uniformity of osseous pattern

CLASS III BONE STRUCTURE

The bone has large marrow filled spaces that exist between bone trabeculae.

Lekholm and Zarb102 classified also bone quality according to the bone found in the anterior mandible to: ©2006 Mireille Wassef

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QUALITY ONE

The bone is composed of homogenous compact bone

QUALITY TWO

The bone has thick layer of compact bone surrounding a core of dense trabecular bone.

QUALITY THREE

The bone has a thin layer of cortical bone surrounding dense trabecular bone of favourable strength

QUALITY FOUR

The bone had a thin layer of cortical bone surrounding a core of low density trabecular bone.

Misch102 extended four bone density groups regardless the location in the jaws; he classified bone according to microscopic findings into five groups:

D1 BONE

Bone mainly formed of dense cortical bone.

D2 BONE

Thick dense to porous cortical bone found on the crest and coarse trabecular bone within these dense cortices.

D3 BONE

Thin porous cortical bone found on crest and fine trabecular bone within these porous cortices.

D4 BONE

Fine trabecular bone. ©2006 Mireille Wassef

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ƒ

D5 BONE

The bone is immature and non-mineralized bone.

BONE AND IMMEDIATE LOADING There are two types of bone around implant insertion. Woven bone which is unorganized, less mineralized, had lower strength and is more flexible forms at a rate of 60 microns per day. Lamellar bone is organized, highly mineralized, strongest bone type and also may be called load – bearing bone. It forms at a rate of up to 10 microns per-day.104 The bone in the macroscopic threads of the implants is stronger the day of surgery than after three weeks as the bone in contact with the implants is a lamellar bone.55 On the day of surgery, there is residual cortical and trabecular bone around the implant when it is inserted. Early cellular repair was started by the surgical trauma and woven bone was formed by the second week after insertion of the implant at a rate of 3050 microns per day. The highest risk of overload is by the third to the fifth weeks as the implant bone interface was at its least mineralization and unorganized at that time.79 Bucks et al.105 found that immediate loading failures occur at the third to the fifth week of implant insertion without infection only from mobility.

Decreasing the risk of immediate occlusal overload was by obtaining vital bone in contact with the implant/bone interface. It is the result of minimizing the surgical trauma that includes thermal injury, mechanical trauma which may cause micro-fractures during implant placement that may lead to implant failure. To maximize the zone of repair, the implant/bone interface should be closely packed with bone meaning that Š2006 Mireille Wassef

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the use of bone tape may exclude the necessity of immediate loading, as it widens the implant space and decrease its contact with bone. 79 When the bone was loaded by implant prostheses, the implant/bone interface began to model by the stress transfer through the occlusal load, the woven bone formed from the mechanical or loading response was called "Reactive Woven Bone".79 If the mechanical situation was too severe; fibrous tissue might form at the implant/bone interface rather than bone.

A study conducted by Romanos et al.106 on monkeys to evaluate the hard tissue reaction around immediately loaded implants placed in the posterior mandible. The study provided two groups one group receiving immediate loading protocol and the other group with two stage surgery delayed loading protocol. In the histological analysis the immediately loaded implants were all osseointegrated, no gaps or fibrous connective tissue was seen between the titanium surface and the alveolar bone. At the crestal and the middle part of the implants a higher deposition of new bone was observed. As for the delayed loaded implants; all implants were osseointegrated no resorption or peri-implant inflammatory reactions were present. At the apical part of the implants cancellous bone had decreased density in comparison with the bone localized around the cervical and middle parts of the implants. The histomorphometric analysis showed the mean values of the bone to implants contact (BIC) for the immediate loading was 64.25% and for the delayed loading 67.93% which did not show any statistical differences between both groups. The bone area within the threads had mean values for immediate loading of 76.95% and for the delayed loading group 65.42% these values showed statistical significance. According to the observation and finding of the study it is concluded that there is a peri implant mineralization area Š2006 Mireille Wassef

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which showed higher density related to the immediately loaded implants than the delayed loading implants so the immediate loading have the potential to increase ossification of the alveolar bone around endosseous dental implants.

Kawahara et al.107 conducted four experiments studying the behaviour of bone to immediate loading and osseointegration. The first experiment utilized a rod-type implant of 2mm diameter 15 mm in length and rough surface of Ra= 2.5 Âą 0.8 Âľm. Four implants were installed on both sides of the mandible and a total of sixteen implants inserted in four beagle dogs six month after extraction of their premolars. After one day of the implantation the implants were fixed with a temporary fixed resin bridge then replaced after suture removal, 10 days after surgery, by gold bridge.

After six and twenty four weeks the dogs were sacrificed. In the second experiment twelve endodontic stabilizers of three different alloys for a total of 36 pins inserted into the premolar and molar region on both sides of the mandible of six beagle dogs. The pins were fixed into the root canals after twenty four weeks the dogs were sacrificed. Third experiment was performed to read the micromotion of fifteen different implants.

Twenty two natural teeth of upper incisors measurement were taken under the static load of 8 N and 10 seconds with a strain meteroscilloscope system. The relationship between the displacements and Periotest values (PTV) was investigated. The fourth experiment, PTV of abutment teeth premolar and molar of mandible and the implants were measured before and after the setting of the temporary resin bridge to predict the micromotion of the natural teeth abutment teeth and implants.

The histological investigation in beagle dogs suggested that the immediately loaded implant in poor bone density becomes more successful by splinting to the proximal. The compromised health of the Š2006 Mireille Wassef

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implant is recovered to an optimal healthy condition by splinting. When the implant is supported with cortical bone buccal a lingual and basal immediately after installation the implant is rigidly fixed in the alveolar bone with less than 30µm of micromotion. The immediately loaded implant may induce new bone growth, creating the implant-sheath-bone around the implant after the implantation, and it can resist biting stress with its biodynamic responses consisting of bone resorption and formation at the bone–implant interface.

PERI IMPLANT SOFT TISSUE AND IMMEDIATE LOADING Branemark et al.55 recommended the healing of the implants under intact mucosa for preventing the epithelial in growths, development of peri-implant infection, and the risk of premature stress on the implant.

Buser et al.108 studied the effect of tissue integration of non submerged, one stage ITI implant without immediate loading after 3 month of implant insertion there was no sign of mobility and there was no clinical signs of peri-implants soft tissue infection. After three years of implant insertion 53 of 55 implants were evaluated 96.2% as successful implant.

The results of this study demonstrated that one stage trans-gingival healing ITI implants integrate dependably in the tissue and that successful tissue integration can be maintained for at least three years.

Moon et al.109 performed a study in order to examine the composition of the connective tissue that forms an attachment to a dental implant.

The study was conducted on six beagle dogs all of them were subjected to surgical extractions of all mandibular premolars. After six months six fixtures were inserted in the mandible, three on each side. After three month healing abutment was installed and a plaque program was initiated, tooth and abutment were cleaned once daily five days per week for six ©2006 Mireille Wassef

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month and then the dogs were sacrificed. Tissues were divided histologically into two zones; zone (A) one central 40Âľm wide unit located immediately next to the implant surface and zone (B) lateral unit 160 Âľm wide that was continuous with the central unit. Zone (A) of this connective tissue was characterized by absence of blood vessels and abundance of fibroblasts which were imposed between thin collagen fibers. The more lateral zone (B) contained comparatively fewer fibroblasts by more collagen fibers and blood vessels. As a conclusion the fibroblasts related to the titanium surface plays a role in the maintenance of a proper seal between the oral environment and the periimplant bone.

Abrahamsson et al.110 conducted a study to compare the periimplant tissue response of non-submerged versus submerged implants on beagle dogs. The maxillary premolars were extracted and left to heal for a period of three months then Astra Tech implant were inserted three in the maxilla and left to be submerged for another three months. After another three months the abutments were inserted along with three non submerged implants on the contra lateral side and connected with abutments. After nine months from the first fixture installation the animals were sacrificed. The histometric analysis included assessment of the vertical dimension of the marginal soft and mineralized periimplant tissues. It was found that the mucosa of the submerged and non submerged has many features in common as the height of the mucosa, the length of connective tissue integration, the percentage of bone to implants contact as well as the density of the periimplant bone therefore it was suggested that a non submerged installation technique might provide conditions for tissue integration similar to those obtained using a submerged approach.

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Rungcharassaeng et al.111 studied the tissue response around immediately loaded, threaded, Hydroxyapatite (Ha) coated dental implants and supported a mandibular overdenture. The periimplant tissue was evaluated both clinically and radiographically up to twelve months after prosthetic placement. At the end of the observation period all implants were stable and no implants were lost. There is a decrease in probing depth and in the plaque index but no significant difference in the frequency of bleeding upon probing. As a conclusion of this study the tissue response of immediately loaded screw implant with Ha coating was favorable and comparable to that of conventional delayed loaded implants after one year.

Siar et al.112 conducted a study with the aim to examine the histomorphometric features of the soft tissues around immediately loaded implants placed in the posterior mandible. Using six adult monkeys on one side was the control group (delayed loading) and the other side the test group (immediately loaded). Implant was inserted in the premolar molar region of the mandible. The animals were sacrificed after three month after loading. Histomorphometric study of the soft tissue indices include sulcus depth (SD), junctional epithelium (JE), connective tissue contact (CTC), biological width (BW= SD+JE+CTC), distance between the implant top and coronal gingiva (DIM), and distance between the implant top and first implant-to-bone contact (DIB). As a conclusion the soft tissue dimensions were in the biological range and there is no difference in soft tissue features between immediate and delayed loading in the posterior location of the implants.

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IMPLANT SURFACES AND IMMEDIATE LOADING DIFFERENT IMPLANT SURFACES AND IMMEDIATE LOADING When the implant surface is modified with a roughened surface texture a significant increase of bone to implants contact is observed.113 The surface condition of the implants is most important in the healing phase and early loading of the implants.

A surface condition that allows higher percentage of bone contact with higher mineralization rate and the fastest lamellar bone formation would be of benefit in the immediate loading.114 The difference in implant stability of machined and roughened surface conditions of threaded implants has been measured and reported with resonance frequency values and the roughened surface definitely increase the initial stability for up to three months.115 Szivek et al.116 conducted a study to examine the strain transfer near a Hydroxyapatite (Ha) coating in canine hip implants simulating the anatomical loading. Cortical bone loss occurred in all implanted femora.

The most extensive loss was related to the proximal section of the implants (47%). Extensive trabecular bone formation over 300 % in some regions of each femur was noted in all implanted femora. Backscattered electron imaging showed bonding of the bone to the implants. Normal light and UV light micrographs showed direct bone apposition to the implant surface and extensive bone formation in all test animals.

Microscopy revealed no evidence of any soft tissue layer between the implant and bone, and the bone was in direct contact with the implant surface. Histomorphometric analysis indicated that bone formation rates in the implanted femora were elevated up to 850% relative to controls.

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Corso et al.117 studied the stability and the effect of immediate masticatory loading of a free standing dental implant with four different surfaces. Forty implants were used in four dogs. Each dog received three HA coated dental implants (test group) and one TPS surface implant (control group). The implant were radiographically evaluated to examine the crestal bone changes and the peri-implant radiolucency, and clinically evaluated by Periotest at the day of loading baseline, one, three, six months. Of the forty implants, thirty nine showed no mobility or radiolucency except for one. No statistical significance between different surfaces was found. As a conclusion for this study immediately masticatory loading in beagle dogs did not jeopardize tissue integrity provided that the implants had excellent primary stability.

Orsini et al.118 conducted an implant surface analysis on ten machined implants and on ten sandblasted and acid-etched implants. Subsequently, sandblasted

and

acid-etched

implant

cytotoxicity,

morphologic

differences between cells adhering to the machined implant surfaces, and cell anchorage were evaluated. Results indicated that acid. The average roughness (Ra) of sandblasted and acid-etched surfaces was about 2.15 microns (¾). Cytotoxicity tests showed that sandblasted and acid-etched implants had non-cytotoxic cellular effects and appeared to be biocompatible. Scanning electron microscopic examination showed that the surface roughness produced by sandblasting and acid etching could affect cell adhesion mechanisms. Osteoblast-like cells adhering to the machined implants presented a very flat configuration, while the same cells adhering to the sandblasted and acid-etched surfaces showed an irregular morphology. These morphologic irregularities could improve initial cell anchorage, providing better osseointegration for sandblasted and acid-etched implants. Š2006 Mireille Wassef

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Proussaefs and Lozada119 examined dental implants retrieved from humans to evaluate the bone-implant interface. This case report presented clinical, radiographic, and histologic evaluation of a cylindrical hydroxyapatite (HA) coated implant retrieved from the posterior maxillary area of a patient after nine years of placement. Clinical examination revealed an immobile implant with no sign of pathosis.

Radiographic examination indicated close proximity of the bone to the implant surface without evidence of radiolucency. Histologically, because of tissue destruction during implant retrieval, only the apical portion of the implant was available for examination under light microscopy, and it appeared to be integrated with the surrounding bone; 45.9% of the surface of the implant had close bone apposition at the interface. There was no evidence of dissolution of the HA coating and the bone appeared to be in immediate contact with the coating.

Novaes et al.120 studied four different implant systems several types of surface treatment, with the aim of optimization the bone-implant contact.

Four mandibular premolars were extracted from male mongrel dogs.

Ninety days after removal, four screw-type implants (Paragon) were placed with different surface treatments in mandible. The dogs received two implants of each of the following surface treatments: smooth (machined), titanium plasma spray (TPS), hydroxyapatite coating (HA), and sandblasting with soluble particles (SBM). The implants were maintained unloaded for 90 days. After this period, histomorphometry was done. The means for all treatments that added roughness to the implant surface were numerically superior to the mean found for the machined surface. However, this difference was statistically significant only between groups SBM and machined. The SBM-treated surface

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provided a greater bone-implant contact than a machined surface after 90 days without loading.

Proussaefs121 presented a clinical report describing the microscopic analysis of a threaded hydroxyapatite-coated root-form implant retrieved from 89-year-old subject after ten months of service. The implant was never loaded. Clinically, the buccal area of the implant was covered by soft tissue, whereas the palatal side was covered by bone. Light microscopic evaluation revealed tight contact between hydroxyapatite and bone with no sign of coating dissolution. Osteocytes were present, and Haversian canals were in close proximity to the implant surface. The buccal side of the implant demonstrated mild to moderate inflammatory infiltrate and signs of hydroxyapatite coating dissolution. These observations

suggested

that

hydroxyapatite

coatings

can

resist

degradation in contact with bone but may be more prone to dissolution in contact with soft tissue.

Proussaefs et al.122 conducted a prospective study evaluating the immediate loading of single, threaded, root-form, hydroxyapatite coated implants, placed in the maxillary premolar area. Ten human subjects were included in this preliminary report. In all cases, a screw-retained temporary acrylic resin crown was placed immediately after implant surgery. The definitive screw-retained metal-ceramic crown was placed six months later. The peri-implant soft tissue parameters mobility, and marginal bone level was measured. Results of the current study provided evidence that, under the condition of this investigation, single root-form implants can be immediately loaded when placed in the maxillary premolar area.

Ibanez and Jalbout94 investigated eleven consecutive patients treated with 87 screw-shaped endosteal acid-etched; Osseotite implants (3I). Two Š2006 Mireille Wassef

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mandibular and two maxillary cases received screw-retained provisional prostheses the day of surgery. Three mandibular and four maxillary cases were loaded 48 hours after surgery with the final screw-retained, porcelain-fused-to-metal prostheses. All implants were followed for two to three years. Follow-up consisted of clinical as well as radiographic examination. All implants were successful. There was no implant mobility or periimplant radiolucency. It is concluded that a high success rate can be achieved when implants with a hybrid surface, machined/acid-etched, are immediately loaded within 48 hours after surgical placement in the maxilla and the mandible.

Taba et al.123 conducted a study to radiographically measure the bone density at the peri-implant region after osseointegration and to compare the relative bone density achieved by different surface-treated implants.

Four different types of implant surfaces were compared, using five young-adult male mongrel dogs. Ninety days after removal, four 3.75-mm diameter and 10-mm long screw implants (Paragon) were placed with different surface treatments in the lower hemi-arches. The dogs received two implants each of the following surface treatments smooth (machined), titanium plasma sprays, hydroxyapatite coating; and sandblasting with soluble particles (SBM). The implants were maintained unloaded for 90 days. After this period, the hemi-mandibles were extracted and radiographed. The grey level of the bone adjacent to implants was measured with a specific software tool (line histogram) and the relative bone density was calculated. The four different surface treatments promote different numeric levels of bone density around the dental implants. The implants can be ranked in terms of relative bone density from high to low as follows: sandblasting with soluble particles, titanium plasma spray, machined, and hydroxyapatite coating. The Š2006 Mireille Wassef

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findings of radiographic density analysis suggest that the soluble blasting media-treated surface provides a greater bone density at the peri-implant region.

Cannizzaro and Leone124 conducted a study to determine the clinical effectiveness of placing dental implants with microtextured surfaces into full occlusal loading. Two demographically similar groups of fourteen patients each were treated with a total of 92 Spline Twist Implants.

Control implants were restored using a conventional delayed loading procedure. Radiographs, periodontal indices, and Periotest values were recorded

every

six

months

during

routine

clinical

follow-up

appointments. The mean loading time for all prostheses was twenty four months. Cumulative implant success was 98.9% for all implants placed (test group = 100%; control group = 92.9%). Immediate full occlusal loading of partial prostheses supported by microtextured implants demonstrated excellent clinical results, with no adverse periodontal effects after twenty four months of function.

Sul et al.125 presented a study to investigate bone tissue reactions to a newly developed calcium incorporated oxidized implant. The specific aim is to assess the effect of calcium surface chemistry on the bone response.

Calcium (Ca) ion-incorporated implants were prepared by micro arc oxidation methods. Surface oxide properties were characterized by using various surface analytic techniques involving scanning electron microscopy, x-ray diffractometry, x-ray photoelectron spectroscopy, and optical interferometry. Twenty screw-shaped commercially pure (CP) titanium implants (10 turned implants [controls] and 10 Ca-incorporated implants [tests]) were inserted in the femoral condyles of 10 New Zealand White rabbits. After a healing period of six weeks, resonance frequency analyses and removal torque measurements of the Ca-incorporated Š2006 Mireille Wassef

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oxidized implants demonstrated statistically significant improvements of implant integration with bone in comparison to machine-turned control implants (p = 0.013 and p = 0.005, respectively). The Ca-reinforced surface chemistry of the oxidized implants significantly improved bone responses in a rabbit model. The present study suggests that biochemical bonding at the bone-implant interface, in combination with mechanical interlocking, may play a dominant role in the fixation of Ca-incorporated oxidized implants in bone. The observed rapid and strong integration of test Ca implants may have clinical implications for immediate or early loading and improved performance in compromised bone.

Nordin et al.126 evaluated the concept of early loading of rough-surfaced implants in the completely edentulous maxilla and in the edentulous posterior mandible and maxilla. Fifty-four consecutive patients were treated. Two hundred thirty-four solid screw-types sandblasted, large-grit, acid-etched (SLA) ITI implants were placed, 58 (25%) immediately after tooth extractions. Mean placement torque and standard deviations were measured at all sites. Sixty fixed prostheses were delivered after a mean delay of 9 days (range, four to twenty two days). Mean marginal bone reduction was measured after one year of loading. Two implants were lost (0.9%), one before functional loading and one after 1 year. All other implants were clinically stable, In this study, favourable results were obtained in 54 consecutive patients in the studied regions. In this study population, early loading protocols can be applied with predictable results using rough-surfaced implants for rehabilitation of the completely edentulous maxilla, posterior maxilla, and posterior mandible.

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METHODS OF EVALUATION OF DENTAL IMPLANTS Longitudinal evaluation of oral implant systems is of most importance for the evaluation of long term survival and complication rates of each system. The clinical periimplant evaluation is important for the detection of early signs and symptoms of disease and subsequently for planning the therapeutic intervention.

According

to

the

European

workshop

on

Periodontology127

PERIIMPLANT DISEASE It was a collective term for inflammatory process in the tissues surrounding an implant.127 PERI IMPLANT MUCOSITIS It was defined as a reversible inflammatory process in the soft tissues surrounding a functioning implant. 127 PERIIMPLANTITIS It was defined as an inflammatory process additionally characterized by bone loss around the dental implant. 127

Evaluation of the periimplant marginal tissues PERI-IMPLANT PROBING DEPTH Increasing in the periodontal depth (PD) and loss in the clinical attachment are signs of periodontal diseases. Therefore, pocket depth is important in the assessment of periodontal status and therapy. 127 The extent of probe penetration is influenced by some factors as probing force, and angulation, probe tip diameter, roughness of the implant root surface, inflammatory state of the periodontuim and firmness of marginal tissues, as well as the access to the tissues.128 Studies Š2006 Mireille Wassef

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conducted on the periodontal depth showed that it fails to locate the histologic level of connective tissue attachment around teeth.129-130 This was explained on the basis that most collagen fibers in the supracrestal connective tissue compartment have been demonstrated a parallel direction to the implant axis.131 -132 Ericsson and Lindhe133 used beagle dogs to compare the extent of probe penetration around teeth and implant under healthy soft tissue conditions compared with natural teeth. Probe tip penetration around two-stage submerged implants ended closer to the alveolar crest. Lang et al.134 studied the single stage non submerged implants in beagle dogs. The density of the periimplant tissues influence probe penetration in the presence of inflamed periimplant tissues. Periodontal probes penetrated close to the alveolar bone exceeding the connective tissue level by mean of 0.52 mm. In healthy periimplant conditions the probe tips may identify the histologic level of the supracrestal connective tissue attachment.

Schou et al.135 in a recent study on monkeys has documented that PD measurements around teeth and implants are different. While there was no difference observed with respect to probe penetration under healthy peri-implants periodontal conditions, mild and severe marginal inflammation around implants was associated with a significantly deeper probe penetration into the supracrestal connective tissue compared to that around teeth. It was concluded by different studies that periimplant PD measurement are more sensitive to force variation than corresponding measurements around teeth.136-137-138-139 In general there are many studies indicated that successful implant allow probe penetration of approximately 3 mm. 134-140-141-142

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Periimplant probing should include the location of the soft tissue margin relative to a fixed land mark point in the implant or its superstructure. 128 In a longitudinal study, Bragger et al.143 found that the connective tissue level in combination with the radiographic parameters after two years of implant loading were good predictors of the periimplant tissue condition.

Repeated periimplant PD measurement may be performed with higher reproducibility by means of an automated controlled force periodontal probe.144 In another study complete attachment of the junctional epithelium were re-established after five days following probing using a conventional periodontal probe. 145 As in the case around teeth periimplant probing disrupts the epithelial attachment but does not cause permanent damage to the transmucosal soft tissue seal.146

Evaluation of the bone implant interface IMPLANT MOBILITY The primary stability at the time of surgery is the most important to achieve osseointegration.147-148-149 The implant mobility indicates the lack of osseointegration, the recording of the implant mobility may be a very specific, but not sensitive, clinical parameter in detecting loss of anchorage. This parameter detects the final stage of Osseo-disintegration and therefore represents a late implant loss. 128

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Pain and discomfort may be associated with increased implant mobility and could be the first signs of indicating implant failure150 and before any radiographic evidence are detected.151 The Periotest* is an electronic device which helps to measure the damping characteristic of the periodontuim around natural teeth and has been recommended to monitor initial degrees of implant mobility or horizontal displacement. 152-153 Damping as defined by the American Heritage dictionary 154 is, “The capacity built into a mechanical or electrical device to prevent excessive correction and the resulting instability or oscillatory conditions.” And according to Wikipedia 155 Damping is “Any effect, either deliberately engendered or inherent to a system that tends to reduce the amplitude of oscillations.”

The Periotest technique involves electronically controlled and reproducible percussion of tooth/abutment. The 'Periotest value' is calculated from the signal of the reaction to a reproducible impact applied to the tooth crown. The visco-elastic properties of a healthy tooth enabling the percussion of the Periotest tapping head to be decelerated in less than 1 ms which are largely lost in periodontitis. This is the essential difference which the Periotest method utilizes.156 The Periotest value depends to some extent on tooth mobility, but mainly on the visco-elastic characteristics of the periodontium. The Periotest value is generally not elevated with infection of the gingivae.

This microcomputerized measuring, steering and speech synthesis systems allows it to quantify in a numeric scale the elasticity of the tissue-

*

Periotest Device; Formerly manufactured by Siemens Dental now by Gulden-Medizintechnik, both D-64625 Bensheim an der Bergstraße, Germany

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implant interface. The point of percussion in routine applications using the standard technique is the centre of the facial surface of the anatomical crown.156 During the measurement, the sleeve of the handpiece may not touch the tooth/abutment. The distance from the tooth/abutment should be 0.5 mm to 2.5 mm. The handpiece should be as horizontally as possible and at right angles to the center of the facial anatomic coronal surface of the tooth/abutment to be examined. Deviations from perpendicular aspect will result in incorrect measurements. During the measurement, the maxillary superior teeth and mandibular teeth must have no contact and the tongue must not contact the teeth. The patient is instructed to open the mouth to facilitate measurement in the lateral zone.157 Differences in the Periotest Values (PTVs) have been reported for implant in the mandible and maxilla with implants in the maxilla showing significantly higher PTVs in patients treated with Branemark system implants this procedure was found to be related to the type of jaw treated implant and abutment length condition of periimplant tissues and bone density. 143-158 The Periotest is capable of providing valuable information concerning favourable or unfavourable changes in the bone-implant interface. In addition, it can help identify when an implant is ready to be loaded. A new range of PTVs (-5 to -2) is suggested for monitoring the status of implants. Implants with PTVs more positive than -2 would could indicate a bone-implant complex that may be hazardous.159

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RADIOGRAPHIC EVALUATION The main purpose of imaging is to assess the level of the alveolar bone including the pattern and extent of bone resorption. A number of intraoral and extraoral imaging modalities are available.

PERIAPICAL RADIOGRAPH The most accurate radiographic projection of alveolar bone level is obtained when the receptor is placed parallel to the tooth and the central ray of the X-ray beam is aimed at right angle relative to the implant and the receptor. 149 The long cone paralleling technique eliminates distortion and limits magnification to less than 10%.160 The placement of a dental implant requires thorough planning to optimize its success and to minimize morbidity. The fabrication of a stent with radiographic marker provides a simple but effective means to identify the location of the recipient sites. 161-162 Optimal projection geometry in the anterior regions is achieved with periapical radiographs using the paralleling technique.163 Small deviations from the optimal geometry are usually better tolerated in the anterior region because of the smaller buccolingual dimension of the teeth and the alveolar bone. 164 Post operative imaging is performed for evaluation of the periimplant bone. A radiograph taken immediately after placement of the implant can serve as a baseline for longitudinal assessments. While some bone loss is expected at the crestal bone around the implant. Follow up radiographs can assist the practitioner in determining whether this loss is within reasonable

limits.

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Osseointegration

can

not

be

determined

Page 53

radiographically although an increase in bone density near the implant bone interface is usually a preferable sign. 164 Edentulous patients with mandibular implant supported overdentures who have suffered from severe bone loss for decades are known as difficult candidates for radiographs of desirable quality. The radiographs more often reveal only the coronal parts of the implants fixtures because of the anatomical difficulties of the premylohoid fossa.165-166 Unfortunately the therapeutic paradigm for mandibular implant supported overdentures requires that implant fixtures are more placed between the mental foramina, hence in the most difficult anatomical area for standardizing imaging procedures. Early and subsequent reports used and extended cone radiograph technique were recommended by Strid.167 Unfortunately there are shortcomings in the Strid technique which should have limited application in standardized overdenture reports. 168 In a study conducted by Gher and Richardson169 comparing the accuracy of dental radiographic techniques; the periapical radiographs produced the most accurate measurements than the Panoramic radiographs. The 90Âş periapical radiograph varied from actual dimensions by 0.0 to 0.3mm so it has the greater edge accuracy and image detail.

May researches used the RinnŽ holder to standardize the periapical radiograph in his research using a paralleling technique. 170-171-172 PANORAMIC RADIOGRAPHS Panoramic radiograph is a curved plane tomographic radiographic technique used to depict the body of the mandible, maxilla and the lower one half of the maxillary sinuses in a single image. Panoramic radiograph is characterized by an image of the jaws that demonstrates vertical and horizontal magnification about 10% to 20% respectively. Diagnostic Š2006 Mireille Wassef

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templates that have 5mm ball bearing s or wires incorporated around the curvature of the dental arch and worn by the patient during the panoramic x-ray examination enable the dentist to determine the amounts of magnification in the radiograph. Generally the maxillary anterior edentulous region is often the most difficult area of the panoramic radiograph to be evaluated because of the curvature of the alveolus and the inclination of the bone. Object in front of and behind the focal trough are blurred, magnified reduced in size or distorted to the extent of being unrecognized. 160 Panoramic radiography allows for assessment of structures such as the maxillary sinus or the course of the mandibular canal and it provides the possibility for vertical measurements with sufficient accuracy if the magnification factor of the panoramic radiograph is known. It is necessary for treatment planning. 173 Dul et al.174 conducted a study to evaluate the different radiographic techniques in patients treated by dental implants. This technique should be performed as general consideration prior to implant placement. The panoramic radiograph considered as a standard radiographic examination that provides a low biological risk while giving an excellent survey and an accurate means of determining implant length in both maxilla and mandible.

Zechner et al. 175 concluded that for highly atrophic mandibles, with unfavourable imaging conditions; the rotational panoramic radiographs can be a useful alternative to intra oral small-format radiographs for evaluating peri-implant bone loss.

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AIM The aim of this study was to assess the changes in crestal bone height and evaluate the clinical osseointegration of two different surface treatments of dental implants, the Hydroxyapatite (HA) surface coating and the Soluble Blasting Media (SBM) of the Paragon Implant system using the immediate loading protocol.

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MATERIALS AND METHODS PATIENT'S SELECTION

Six Male Patients were subjected to the present study and selected from the outpatient clinic of the faculty of Oral and Dental Medicine, Ain Shams University according to certain criteria: Patients were completely edentulous.

Patients had reasonable inter-arch distance of at least 15 mm.

Patients were free from any systemic disease as diabetes and hypertension.

Patients subjected to the study had Angle class I jaw relationship.

Patients who were excluded either lacked motivation, had parafunctional habits or smokers.

PATIENT EXAMINATION: •

General Examination

A diagnostic sheet was filled, and the patients, were subjected to thorough diagnosis to examine: (Fig 1)

Ridge form and texture

Mucosa colour and uniformity

Presence of any bony specules or flabby ridge

Presence of ulcers or burning sensation in the mouth

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•

Cast trimming

Full arch primary impression by alginate impression (Cavex*) was taken and processed into a 1ry cast.

The duplicate lower cast was trimmed at the proposed areas of surgery “Interforaminal area.”

•

Only patients who had at least 8mm width were chosen.

Interarch distance evaluation

The upper and lower casts were used for occlusion block construction after tentative jaw relation registration; the Interarch distance was evaluated by the use of curved campus upon the bite block. Fig (2) •

Radiographic evaluation

All patients were evaluated through panoramic radiograph to examine the condition of the bone height and a preliminary idea about the thickness and quality of the bone was concluded.

Only patients with 19-20 mm bone height at least were participated in the study.

*

Cavex Holland BV , Haarlem, Holland

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Fig (1) Diagnostic sheet

Fig (2) Curved campus

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PRESURGICAL PROCEDURE

•

Patient preparation

Patients were subjected to several sessions of patient

education in implant importance, need, advantages, maintenance and care.

Patients were prepared via proper oral hygienic measures

and dental care instructions.

Signed consent was drawn from each patient for agreement and approval of the surgical operation.

•

Complete denture construction

Complete dentures were constructed for all patients

following the conventional technique except the following: ¾ High impact acrylic resins (Meliodent™*) and cross linked acrylic artificial teeth (Vivadent™†) were used. ¾ Lingualized occlusal scheme was established by reduction of all the upper buccal cusps of posterior teeth. ¾ Before try in stage, check of the bar space was done. ¾ The patients were delivered with a complete denture and instructed to use it for at least two to three weeks before surgical procedure.

*

Heraeus-Kulzer GmbH, Wertheim, Germany.

†

Ivoclar Vivadent AG, Bendererstrasse, 2 FL-9494 Schaan Liechtenstein.

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•

Surgical stent

Duplicate of the patient's denture was manufactured

acting as a surgical and radiographic stent.

The stent was constructed with four metal balls 5 mm in

diameter, two anterior and two in the premolar region. The stent was used while making the panoramic radiograph. Fig (3) •

Radiographic examination

The patient was subjected to panoramic radiograph with

the stent in place showing the position of the balls and identifying the sites of the mental foramina. Fig (4)

The patient was subjected to occlusal radiograph with the

stent in place. Two radiographs with two positions, tomography view, and right angle view were made. Fig (5)

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Fig (3) Radiographic stent with 4 balls 5mm in diameter

Fig (4) Panoramic radiograph with an edentulous upper and lower arch showing 4 balls

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Fig (5) Occlusal Tomogram radiograph showing four balls and thickness of the mandible

Fig (6) Paragon complete implant for one stage surgical protocol

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IMPLANT SELECTION •

Type Four screw type non submerged implants♦ 3.75 mm in diameter

and nearly has 70% of the mandibular height at the selected area were used for all cases. Fig (6) Two selective surfaces implants coated with Hydroxyapatite (HA), and implants grit blasted with soluble blasting media (SBM™♦) were chosen. The sequence in which the implants were installed in the jaw was alternative.

•

Implant Location The implants were located at the inter-symphesial area between

the mental foraminae. The site of the implants was marked by the aid of radiograph taken with the acrylic stent containing the metal balls.

The stent was modified to serve as surgical stent.

At least 3mm of residual bone was present between the distal

implant and the adjacent mental foramen.

THE SURGICAL PROCEDURE: The surgical procedure was carried out after two to four weeks of denture insertion.

♦

Paragon Implant Company, Encino, California, USA.

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•

Modification of template

Transparent acrylic stent was modified to be a surgical

template from the anterior region exposing the anterior segment only to the premolar areas. (Fig 7) • Examination

The intact edentulous ridge was examined for any

inflammation or soreness or ulcer before proceeding to the surgical procedure. (Fig. 8) • Patient Preparation

Premedication was given to the patient such as anti

inflammatory

(diclofenac

sodium*

50mg)

and

antibiotics

(Clavulanate-potentiated Amoxycillin† 1 gm every 12 hours 24 hours) prior to surgery, mouth wash (chlorhexidine♦) was also instructed to the patient three times per day for 3 days prior to surgery.

The peri-oral region of the patient was cleaned by

antiseptic solution (Betadine antiseptic solution♥).

The surgical template was sterilised by antiseptic solution

(Cidex‡)

*

Cataflam, Novartis Pharma, Basle, Switzerland Augmentin, Medical Union Pharmaceuticals Co. Abu Sultan, Ismailia, Egypt Under Licence from Beecham Pharmaceuticals Brentford, England A SmithKline Beecham Company ♦ Antiseptol mouth wash, El Kahira Co. Egypt ♥ The Nile Co for Pharmaceuticals and Chemical Industries- Cairo- A.R.E. licensed by Mundipharma AG- Basel- Switzerland. †

‡

Cidex Activated Dialdehyde Solution J&J Medical

©2006 Mireille Wassef

Page 65

• Anaesthesia

The patient rinsed with 0.1% chlorhexidine♦ before

surgery to disinfect the field of the operation

Nerve block anaesthesia administrated to the patient on

both sides of the arch.

IMPLANT INSTALLATION •

Incision and flap elevation

The stent was inserted in the patient's mouth to indicate

the length of the crestal incision. (Fig. 9)

A mid crestal incision was carried out to expose the

alveolar ridge with two releasing incisions bucally. (Fig.10)

After bone exposure, the buccal flap was reflected by

periosteal elevator (Ash♦).

•

Implant site preparation

Copious irrigation through out the procedure was carried

using internal and external irrigation with saline. Suction was carried out using a high suction machine.

The four implant installation sites emergence points were

marked on the alveolar crest by indelible pencil. (Fig. 11)

Flattening of these sites was done by football surgical

carbide bur (Ash).

♦

Ash, DENTSPLY Ltd Hamm Moor Lane, Addlestone, Weybridge, Surrey

.

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The cortical bone was penetrated firstly by 2mm pilot drill

with constant profuse saline irrigation followed by successive drills 2.8 mm, 3.4 mm respectively using a speed of 2000 rpm, high torque and internally irrigated headpiece. (Fig 12)

The movement of the drills in the osteotomy site was in a

pumping successive vertical movement.

The bone chips in the flutes of the drills were constantly

removed to avoid bone heating.

During and after the preparation of the osteotomy site

paralleling devices were used. At least 7 mm between the centres of each two adjacent implants was established. (Fig. 13, 14) •

Implant Installation

The two selected surfaces (HA and SBM) of the four

implants were inserted alternatively. (Fig. 15)

The implants were positioned according to the direction

of the preparation site.

The implants were tapped by manual wrench into its place

in the osteotomy site.

After

insertion

of

the

four

implants

with

the

predetermined sequence, healing caps were screwed into their corresponding implants.

•

Flap repositioning and suturing

The surgical site was profusely irrigated with saline and

cleaned for all bone chips. Soft tissue tags were removed.

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The flap was replaced and compressed in order to obtain

complete closure of the soft tissue

Simple interrupted suture was performed using silk triple

O sutures. (Fig 16, 17) POST SURGICAL MEDICATION After surgery, each patient was instructed to follow post surgical medication.

Patients were instructed to apply cold pack after the surgical procedure for the first six hours, as for each half hour a 10 min cold application was recommended.

Antibiotic injection, Cefotaxime* 500 mg intramuscular (IM), each 24 hours for one day after operation.

Steroid injection Dexamethasone† 8 mg was injected IM immediately after surgery.

The patient was injected with non steroidal anti-inflammatory NSAID at the day of the surgery.

The patient was instructed to follow an antibiotic regimen for at least 5 days post operative by the same antibiotic started before surgery.

Oral anti-inflammatory was prescribed to the patient to ease pain if present starting from the second day after surgery, diclofenac sodium* 50 mg.

* †

cefotax, Eipico, Egypt Fortecortin; Merck, Darmstadt, Germany

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All patients were instructed to rinse 3 times per day post surgical with 0.2% chlorhexidine† mouth wash.

Fig (7) Radiographic stent modified anterioly.

Fig (8) intact ridge before incision

* †

Cataflam, Novartis Pharma, Basle, Switzerland Antiseptol mouth wash, El Kahira Co. Egypt

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Fig (9) Stent in the patient's mouth before incision.

Fig (10a) Mid crestal incision with two releasing vertical incisions.

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Fig (10b) Alveloplasty and surgical stent placement.

Fig (11) Marking of the places of the implant sites.

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Fig (12) Four osteotomy sites.

Fig (13) Paralleling pins inside osteotomies.

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Fig (14) Paralleling pins across the arch after completion of osteotomy.

Fig (15) Paragon implant insertion.

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Fig (16) Four Paragon implants with healing caps after insertion.

Fig (17) Soft tissue closure with triple 0 black silk sutures.

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PROSTHETIC PROCEDURE After placement of the implant and closure of the soft tissue, post surgical prosthetic procedures were carried out.

The Hader Gold Copping (HGC) was selected according

to the height of the gingiva either HGC3 (3mm) or HGC5 (5mm). Gold cylinder abutments were placed on the four implants and fixed with cylinder fixation screw.

The Hader gold bar was cut to appropriate length that fit

accurately between the gold cylinders.( Fig. 18)

At least 1 mm space was left between bar and tissue. (Fig.

20)

The bar was looted to the cylindrical Hader Gold Copings

with autopolymerised burnout acrylic. (Duralay)♦ ( Fig. 19)

The cylinders with the bar splinted together were

unscrewed and then the gingival caps were placed into implants.

The assembly was soldered in the laboratory using a

soldering gold alloy for gold soldering.* ( Fig. 21)

The Patient was recalled within 48 hours for insertion of

the assembly that was placed passively onto the implants.

Adequate clearance in the denture base was created to

accommodate for the bar and implants.

♦ *

Dental Manufacturing Co., Worth, Ill. USA Gold Alloy Soldering 18 Karat ( Degussa, Germany)

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The denture was first relieved against the bar so that the

patient could close in normal occlusion without rocking or pressure on the bar or the abutments.

The pick up procedure was conducted after the bar was

soldered into its place in the patient's mouth by closing all undercuts of the bar and the abutments with sticky red wax. Fig. 22)

The Hader Clip was fixed to the bar and verified for its

adequate fitting. The relieved area of the denture base was filled by auto polymerized acrylic resin and inserted. The patient was instructed to bite lightly in centric occluding relation.

After

curing

of

the

autopolymerised

resin,

the

overdenture was removed carefully from the patient's mouth with the clips picked up on its fitting surface. ( Fig. 23)

Patients were reminded of the importance of the oral

hygiene measures and the way of prosthesis insertion and removal of the prosthesis.

The patient was dismissed until suture removal

appointment from 7 to 10 days after surgical procedure.

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Fig (18) Hader bar is cut according to the space available.

Fig (19) Hader bar fixed in place by autopolymerised burnt out acrylic resin. (Duralay)

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Fig (20) Space between bar and tissue.

Fig (21) Soldering of the gold bar in the laboratory.

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Fig (22) Blockage of undercut during clip pick up.

Fig (23) denture fitting surface with the Hader clips.

METHODS OF EVALUATION The effect of different implant surfaces on the supporting structure was evaluated by:

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•

Subjective evaluation:

The observation of any complication that occurred during

the various stages of the implant treatment was recorded

The information was gathered about function comfort

and overall satisfaction.

•

Peri implant tissue

Periimplant

condition

was

evaluated

during

the

observation period at the three months, six months, nine months and one year after implant loading.

Probing depth at mid buccal, mesial and distal surfaces

was measured in relation to the neck of the implants by the use of periodontal probe (Hu Friedy♠) and the average of readings around all the surfaces was considered as the mean value for the implant in question. (Fig.28) •

Changes of marginal bone height

A radiographic acrylic template was fabricated on the

overdenture of the patient to standardize the periapical radiograph and to hold the Rinn XCP Holder♥ . (Fig 24, 25a, b)

Periapical radiograph using parallel technique was

conducted to monitor the changes in marginal bone height. Using a Rinn film holders the periapical radiograph was taken at the time of insertion of the bar and three, six, nine and twelve months interval.

♠

Hu-Friedy Mfg. Co., Inc. Zweigniederlassung Deutschland Rinn Corporation, XCP instruments for extension cone paralleling technique, IL., USA.

♥

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Standardized panoramic radiograph was taken to evaluate

the marginal bone loss around implants simultaneously at the time of bar placement (base line) and three, six, nine and twelve months period follow up.

The periapical and the panoramic radiographs were

processed to Digora software single user demo♦ , to measure the bone level changes through out time. ( Fig. 26, 27)

The changes in the height of bone was measured mesial

and distal to the implant by tracing a line tangent to the implant thread from the highest point of the alveolar crest to the most apical end of the implant.

The mean value of the readings of both HA implants was

calculated and considered mean value of the bone height of that type. The same was done for the SBM selective surface implant.

•

Implant tissue interface evaluation (Periotest)

Damping of the implants was evaluated by Periotest.♣

(Fig.29, 30, 31)

During the measuring; the patient was sitting upright, the

sleeve of the hand piece did not touch the implant and distance was at least 0.5-1.5 mm. The hand piece was placed horizontally parallel to the floor at right angle to the axis of the implant and at the centre of the implant facial surface. The tongue of the patient was away from the abutment.

♦

Digora for windows 2.5 Rev 0, Build 68, Copyright© 1993-2004, Soredex, Finland Manufactured by Siemens Dental now by Gulden-Medizintechnik, both D-64625 Bensheim an der Bergstraße, Germany ♣

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For each patient the means of the Periotest values (PTVs)

scores were calculated from three repeated readings and the average of both implants types were considered the actual reading for that type.

Significance of Periotest values were as follows: (-0.8 to

0.1) meant that the implant was considered osseointegrated, (000.9), meant that clinical examination was necessary and (+10 and higher) was alarming indicating that the implant was not sufficiently osseointegrated.

A significant audible sound was heard when faulty

application of the Periotest was performed

Fig (24) Rinn holder XCP long cone technique.

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Fig (25a) Radiographic stent for long cone technique lingual side.

Fig (25b) Radiographic stent for long cone technique occlusal view

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Fig (26) Periapical radiograph measured by the Digora software.

Fig (27) Probing depth mid buccal reading.

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Fig (28) Periostest.

Fig (29) Periotest measuring the damping of the implants.

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Fig (30) Periotest screen.

PATIENT FOLLOW UP Routine visits were performed at three months, six month, nine months and one year intervals for collection of data and evaluation of the patients.

STATISTICAL ANALYSIS

Statistical analysis of this study was carried out using S-Plus Statistical Software (SPSS – Release 12) for Windows. Paired t-test was used for testing significance between means of the changes in marginal bone height, probing depth, and Periotest values results throughout the observation period. It was also used for testing the effect of time on the studied variables. Pearson's correlation coefficient was used to correlate between the Periotest readings and the changes in bone height mesial and

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distal to the implants, as well as for the correlation between the length of the implant bar distance between each other and marginal bone height.

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RESULTS All patients attempted the follow up period (January 2003- October 2004) during which data was extracted from their radiograph to evaluate the crestal bone height in relation to the two proximal selective surfaces Hydroxyapatite (HA) and Soluble Blasting Media (SBM) surfaces of the used implants, along with the Periotest values (PTVs) and the probing depth (PD). During the course of the follow up, two implants failed to osseointegrate in only one patient. Another patient dropped out from the follow up period of the investigation and the data was not added to the present study.

All patients were adjusted with there prosthesis without any complaints.

The prosthesis fulfilled both function and aesthetics for all patients.

Statistical analysis of this study was carried out using S-Plus Statistical Software (SPSS – Release 12) for Windows.

Paired t-test was used for testing significance between means of the changes in marginal bone height, changes in probing depth, and changes in Periotest values in relation to the implants throughout the observation period. It was also used for testing the effect of time on the studied variables as well as on the percentages changes through time between the variables.

Statistical significance is achieved when the (P-value ≤ 0.05).

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CHANGES

IN MARGINAL BONE HEIGHT OF THE TWO SELECTIVE

SURFACES

PATTERN OF CHANGES IN MARGINAL BONE HEIGHT MESIAL TO THE IMPLANTS

The mean of the pattern of changes in marginal bone height mesial to implants in relation to Ha and SBM selective surfaces was compared.

The means, standard deviation values (SD) are presented in the (Table 1):

Periapical radiograph SURFACE

HA

SBM

MEAN

SD

MEAN

SD

Immediate

11.32

1.06

10.27

1.36

3 months

10.21

0.97

9.54

1.08

6 months

9.86

1.22

8.89

0.96

9 months

10.3

0.84

8.99

1.13

12 months

9.86

0.91

9.04

1.09

PERIOD

Table 1: The Pattern of Changes in marginal bone height mesial to the implants in Periapical radiograph of the HA and SBM selective surfaces

The mean of the pattern changes of the marginal bone height mesial to implants with HA and SBM selective surfaces showed slight reduction at three and six months which remained nearly stable at nine and twelve months (Table 1 and Histogram 1).

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Pattern Changes in marginal bone height mesial to the implants (Periapical radiograph)

9.86

9.04

10.3 8.99

8.89 9.86

8

9.54 10.21

10

10.27 11.32

Mean bone height (mm)

12

HA

6

SBM 4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 1: Relationship between the crestal bone height mesial to the implants with the HA and the SBM surfaces

On comparing the pattern of changes in bone height in relation to the two selective surfaces both surfaces demonstrated almost parallel pattern along the study period immediate, three, six, nine and twelve months (Linear Histogram 1).

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Pattern Changes in marginal bone height mesial to the implants (periapical radiograph)

8

9.345

HA SBM 8.685

9.385 8.55

8.565

8.5

9.14

9

9.39

9.32

9.5

9.9

10 9.975

Mean bone height (mm)

10.5

7.5 Immediate

3

6

9

12

Period (months)

Linear Histogram 2: Patient one, Pattern changes of the marginal bone height mesial to

the implants with the HA and the SBM surfaces.

On analyzing the pattern of changes for each patient separately the linear histogram for patient one showed that the curve for the marginal bone height in relation to HA selective surface coincided with the curve for SBM selective surface at the beginning of the observation period.

Both had the same reduction for the bone height at three months but at six months the reduction of bone height was more for the SBM surface, at nine months the same relation was maintained, and at twelve months the relation was reversed with increase bone height for SBM and more reduction of bone height for HA selective surfaces (Linear histogram 2).

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Pattern Changes in marginal bone height mesial to the implants (periapical radiograph)

9.96 10.41

8.21 8.15

11.15

10.37

10.4

8

9.64

10.9

10

10.91

Mean bone height (mm)

12

6

HA SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 3: Patient two, Pattern changes of the marginal bone height mesial to

the implants with the HA and the SBM selective surfaces.

The pattern of marginal bone changes mesial to the two selective surfaces in patient two showed close proximity of the bone height at the immediate loading period. At three months there was more reduction in bone height for the HA selective surface while at six months both had the same reduction, at nine months both showed increase in marginal bone height and by twelve months they showed the same level of change in bone height (Linear Histogram 3).

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Pattern Changes in marginal bone height mesial to the implants (periapical radiograph)

10.03 10.785

11.045

9.745

11.405

10.245 11.335

8

10.585

10

12.75

12 11.25

Mean bone height (mm)

14

HA SBM

6 4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 4: Patient three, Pattern changes of the marginal bone height mesial to the implants with the HA and the SBM selective surfaces.

For patient three, the SBM and HA selective surfaces curves for mesial marginal bone height ran in almost parallel pattern showing slight reduction through out the observation period (Linear Histogram 4).

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Pattern Changes in marginal bone height mesial to the implants (periapical radiograph)

7.65 9.85

7.97 10.05

6

8.2 9.975

8.275 10.12

8

11.13

10

8.695

Mean bone height (mm)

12

HA SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 5: Patient four, Pattern changes of the marginal bone height mesial to the implants with the HA and the SBM selective surfaces.

Patient four showed also a slight reduction in mesial marginal bone height with the curves for the HA and SBM selective surfaces running in an almost parallel pattern (Linear Histogram 5).

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Pattern Changes in marginal bone height mesial to the implants (periapical radiograph)

9.325 9.615

10.855

8

10.55

11.205 11.98

12.53

11.805

10

13.295

12 12.22

Mean bone height (mm)

14

HA SBM

6 4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 6: Patient five, Pattern changes of the marginal bone height mesial to the implants with the HA and the SBM surfaces

For patient five on comparing the pattern of reduction in marginal bone height in relation to the HA and SBM selective surfaces both showed a pattern of slight bone reduction (Linear Histogram 6).

PATTERN CHANGES IN MARGINAL BONE HEIGHT DISTAL TO THE IMPLANTS

On comparing the pattern of bone changes between the HA and SBM selective surface distal to the implants, the means, standard deviation values (SD) was presented in the (Table 2):

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PERIAPICAL RADIOGRAPH SURFACE

HA

SBM

MEAN

SD

MEAN

SD

Immediate

10.97

0.87

9.63

1.01

3 months

10.11

0.7

9.61

1.29

6 months

10.1

1.22

8.98

1.1

9 months

10.21

0.76

9.34

1.09

12 months

10.15

0.7

9.17

1.23

PERIOD

Table 2: Pattern changes in marginal bone height distal to the implants in Periapical radiograph of the HA and SBM selective surfaces

The pattern changes for the means of the marginal bone height distal to the implants with the HA and SBM selective surfaces recorded immediate after implants placement, three months, six months, nine months and twelve months intervals showed minimal reduction of the bone height through out the observation period (Table 2).

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Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

9.17 10.15

9.34 10.21

8.98 10.1

8

9.61 10.11

10.97

10 9.63

Mean bone height (mm)

12

HA

6

SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 7: Pattern Changes in marginal bone height Distal to the implants with the HA and the SBM surfaces

For the HA selective surface the curve demonstrated a slight reduction in bone height at three months but remained stable through out the observation period. While for the SBM selective surface, marginal bone height was reduced by six months and remained stable for the rest of the observation period (Linear Histogram 7).

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Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

9.89

9.8

8.6

9.545

9.345 8.91

8.8

9.17

9

8.99

9.25

9.2

9.335

9.4

HA 9.29

9.6 9.65

Mean bone height (mm)

10

SBM

8.4 Immediate

3

6

9

12

Period (months)

Linear Histogram 8: Patient one, Pattern changes of the marginal bone height distal to the implants with the HA and the SBM surfaces.

For patient one the curves of the HA and SBM selective surfaces demonstrated the same pattern of bone reduction distal to the implants through out the observation period. At three and six months remarked bone reduction was observed. At nine and twelve months the height of marginal bone was increased for both surfaces with slight more increase for the SBM over the HA selective surface (Linear Histogram 8).

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Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

9.97

9.57

10.78

10.66

6

8.52

8.053

10.66

8

9.46

10

10.74 10.95

Mean bone height (mm)

12

HA SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 9: Patient two, Pattern changes of the marginal bone height distal to the implants with the HA and the SBM surfaces.

The pattern of marginal bone changes distal to the two surfaces in patient two showed the close proximity of the bone height at the immediate loading period. At three months there was more reduction in bone height for the HA selective surface while at six months both surfaces showed close proximity of marginal bone height reduction. At nine months both showed increased in marginal bone height and at twelve months two surfaces showed almost the same level of bone reduction (Linear Histogram 9).

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Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

10.705

9.81

10.84

10.005

11.26

10.445

8

10.92

10

10.795

12

10.555 12.03

Mean bone height (mm)

14

HA SBM

6 4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 10: Patient three, Pattern changes of the marginal bone height distal to the implants with the HA and the SBM surfaces.

For patient three the level of marginal bone height distal to the implants for both selective surfaces showed parallel pattern of reduction throughout the observation period. At three months the SBM and HA curves coincided (Linear Histogram 10).

Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

10.32

10.55 7.65

10.855

8

6

7.825

8

8.125 10.52

10

8.46 10.645

Mean bone height (mm)

12

HA SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 11: Patient four, Pattern changes of the marginal bone height distal to the implants with the HA and the SBM surfaces

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For Patient four the SBM and HA selective surfaces curves for distal marginal bone height ran in almost a parallel pattern showing slight reduction through out the observation period (Linear Histogram 11).

9.37

10.515

6

9.295

12.15

11.49

10.505

8

11.3

10

11.945

12 12.27

Mean bone height (mm)

14

13.305

Pattern Changes in marginal bone height distal to the implants (Periapical radiograph)

HA SBM

4 2 0 Immediate

3

6

9

12

Period (months)

Linear Histogram 12: Patient five, Pattern changes of the marginal bone height distal to the implants with the HA and the SBM surfaces.

For patient five on comparing the pattern of reduction in marginal bone height in relation to the HA and SBM selective surfaces both showed close proximity of the pattern with slight bone reduction throughout the observation period (Linear Histogram 12).

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PERCENT CHANGES IN MARGINAL BONE HEIGHT OF THE TWO SELECTIVE SURFACES

PERCENTAGE CHANGES IN MARGINAL BONE HEIGHT MESIAL TO THE IMPLANTS

Paired t-test was used to compare between percentage changes in marginal bone height mesial to the implants with Hydroxyapatite (HA) and soluble blasting media (SBM) selective surfaces. The means, standard deviation values (SD) and results of paired t-test are presented in the following tables and graphs: SURFACE PERIOD

HA

SBM

MEAN% SD MEAN% SD

Immediate 3 months Immediate 6 months Immediate 9 months Immediate 12 months

TVALUE

PVALUE

9.3

5.7

6

3.3

1.448

0.207

10.6

4.5

9.7

6.5

0.382

0.718

10.4

4.7

1.3

0.7

4.956

0.004*

13.9

2.7

12.8

6

0.414

0.696

Table 3: Percentage change of marginal bone height mesial to the implant with HA and SBM selective surfaces

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13.9

10.4

9.3

1.3

4

Immediate -9

Immediate -6

2 0

(SBM)

Immediate - 12

6

(HA)

6

8

10.6

10

9.7

12

Immediate -3

Percentage change (%)

14

12.8

percentage changes of marginal bone height mesial to the implants with two selective surfaces

Period (months)

Histogram 13: Percentage change of marginal bone height mesial to the implants with HA and SBM selective surfaces

the difference in percentage changes of the marginal bone height mesial to the implants between the HA and the SBM selective surface showed non statistical significance (P>0.05) at three and six months by nine months the difference was statistically significant (P ≤ 0.05) showing less reduction in bone height in relation to the SBM selective surface and at twelve months the percentage changes was statistically non significant (P>0.05), (Table 3 and Histogram 13).

COMPARISON BETWEEN PERCENTAGE CHANGES IN MARGINAL BONE HEIGHT DISTAL TO THE IMPLANTS

Paired t-test was used to compare between percentage changes in marginal bone height distal to the implants with Hydroxyapatite (HA) and soluble blasting media (SBM) selective surfaces. The means, standard

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deviation values (SD) and results of paired t-test are presented in the following tables and graphs: HA

SURFACE

SBM

MEAN% SD MEAN% SD

PERIOD

Immediate 3 months Immediate 6 months Immediate 9 months Immediate 12 months

TVALUE

PVALUE

7.8

7.4

0.8

3.8

1.657

0.158

6.5

9.5

0.8

0.9

1.427

0.213

8.8

6.8

3.8

3.9

1.190

0.288

8

9.2

4.1

8.3

0.643

0.549

Table 4: Percentage change of marginal bone height distal to the implant with HA and SBM selective surfaces

Percentage changes of marginal bone height distal to the implants with two selective surfaces 9

(HA)

(SBM)

8.8

8

7.8

7

6.5

6

3.8

5

4.1

4

0.8

2

0.8

3

Immediate 12

Immediate 9

0

Immediate 6

1 Immediate 3

Percentage change (%)

8

Period (months)

Histogram 14: Percentage change of marginal bone height distal to the implant with HA and SBM selective surfaces

Although the percentage reduction in marginal bone height in relation to HA was more than that related to the SBM selective surface through Š2006 Mireille Wassef

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out the observation periods the difference was statistically non significant (P>0.05), (Table 4, Histogram 14).

PERIOTEST PERIOTEST RESULTS OF THE TWO TYPES OF SELECTIVE SURFACES Paired t-test was used to compare between values of Periotest for implants with Hydroxyapatite (HA) and soluble blasting media (SBM) selective surfaces. The means, standard deviation values (SD) and results of paired t-test are presented in the following (Table 5).

PERIOTEST SURFACE

HA

SBM

T-VALUE

P-VALUE

MEAN

SD

MEAN

SD

Immediate

-2

2

-0.88

1.33

-1.033

0.336

3 months

-3.25

2.25

-2.48

2.24

-1.730

0.127

6 months

-4.13

1.96

-2.5

1.85

-2.600

0.035*

9 months

-3.88

1.73

-4.38

1.41

0.935

0.381

12 months

-4.25

1.49

-4.13

1.13

-0.357

0.732

PERIOD

Table 5: Periotest mean value of the HA and the SBM selective surfaces

No statistical significant difference (P > 0.05) between implants with (HA) and implants with (SBM) selective surfaces was observed immediately, three, six, nine and twelve months after the use of implants loading while there was a statistically significant difference (P ≤ 0.05) between implants with (HA) and implants with (SBM) after six months of the implants loading.

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Comparison between periotest results for the two surfaces 0

-1

Immediate

-0.88

-0.5

3

6

9

12

HA SBM

-4.5

-4.13

-4

-4.25

-4.13

-3.5

-4.38 -3.88

-3

-2.5

-2.5

-2.48

-2

-3.25

-2

Mean score

-1.5

-5 Period (months)

Linear Histogram 15: Periotest values of the implants with the HA and the SBM selective surfaces

The difference between the mean PTV for the HA and SBM selective surfaces of all patients showed lesser values in relation to the SBM than the HA selective surface through the observation period immediate, three, six months. At the nine months the PTV of the HA increased in relation to the SBM selective surface then decreased by the end of the observation period Linear Histogram 15).

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Comparison of Periotest Values of the Ha and SBM selective surfaces 0.5

3

0.1

Immediate

6

9

12

-1

-0.5

-0.5

-0.5 HA SBM

-2.5 -2.5

-3

-2.5

-2.5

-2.5

-2

-1.5

-1.5

-2

Mean bone height (mm)

0

Period (months)

Linear Histogram 16: Patient one, Periotest value of the implants with the HA and the SBM surfaces

The mean of the PTV showed close proximity at the immediate loading period. And an increase toward positive values was observed at three months for the two surfaces. At six months a steep reduction towards negative values was observed for the HA. By nine months both reached the same values of PTV and maintained these values till twelve months (Linear Histogram 16).

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Comparison of Periotest Values of the Ha and SBM selective surfaces

0 -0.5

Immediate

3

6

9

12

-1

HA SBM

-1.5

-2 -3

-2 -3

-3.5

-3

-3

-2

-2.5

-3

-2

-2.75

Mean bone height (mm)

0.5

0.2

0.45

1

Period (months)

Linear Histogram 17: Patient two, Periotest value of the implants with the HA and the SBM surfaces.

For patient two both surfaces demonstrated similar PTV immediate after implant loading. At three months both surfaces showed a direction towards positive values. By six months the values decreased for both surfaces and were maintained for the rest of the observation period (Linear Histogram 17).

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Comparison of Periotest Values of the Ha and SBM selective surfaces 0 6

9

12

-2 HA

-3

SBM

-4

-4 -5.5

-4

-4

-5.5

-3.5

-3

Mean bone height (mm)

3

-0.75

Immediate -1

-5.5

-6

-5.5

-5

Period (months)

Linear Histogram 18: Patient three, Periotest value of the implants with the HA and the SBM surfaces.

The mean PTV for Patient three showed similar pattern of reduction in values from immediate loading to three months which was maintained though out the observation period for both surfaces with minimal changes (Linear Histogram 18).

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Comparison of Periotest Values of the Ha and SBM selective surfaces 0 6

9

12

-2 -3

-2

HA SBM

-6

-5

-6

-6

-5 -4.5

-5

-4.5

-4 -5 -4.5

Mean bone height (mm)

3

-0.5

Immediate -1

-7 Period (months)

Linear Histogram 19: Patient four, Periotest value of the implants with the HA and the SBM surfaces.

Patient four showed similar PTV for both surfaces at immediate and three months. At six months the values for HA decreased in relation to the SBM selective surface, by nine months the values for HA increased more than the SBM selective surface. By the end of the observation period the relation was reversed (Linear Histogram 19).

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Comparison of Periotest Values of the Ha and SBM selective surfaces 0 Immediate

3

6

9

12

-3

-2.5 -2

-2 -1.5

-2

-1.25-1

HA SBM

-4

-5

-5

-5-4.5

-4

Mean bone height (mm)

-1

-6 Period (months)

Linear Histogram 20: Patient five, Periotest value of the implants with the HA and the SBM surfaces

Patient five, the PTV for HA and SBM showed similar values immediate after implant loading, by three months and six months the values decreased with the same relation for both surfaces. At nine months the relation of the HA and SBM selective surfaces was reversed and maintained reduction till the end of the observation period (Linear histogram 20).

EFFECT OF TIME ON DAMPING OF THE IMPLANTS (PERIOTEST VALUES) The effect of time on Damping of the implant expressed by the Periotest Values was evaluated by Paired t-test. The means, standard deviation values (SD) and results of paired t-test are presented in the following tables and curves:

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Periotest value related to HA OBSERVATION

MEAN

PERIODS

CHANGE

Immediate - 3 months

1.25

Immediate - 6 months

SD

T-

P-

VALUE

VALUE

2.66

1.330

0.225

2.13

2.7

2.229

0.061

Immediate - 9 months

1.88

2.59

2.049

0.080

Immediate - 12 months

2.25

2.25

2.826

0.026*

Table 6: Effect of time on the mean of the Periotest Value related to the HA selective surface

Periotest Value related to SBM OBSERVATION

MEAN

PERIODS

CHANGE

Immediate - 3 months

1.60

Immediate - 6 months

SD

T-

P-

VALUE

VALUE

2.57

1.764

0.121

1.63

2.40

1.914

0.097

Immediate - 9 months

3.50

2.28

4.335

0.003*

Immediate - 12 months

3.25

2.07

4.440

0.003*

Table 7: Effect of time on the mean of the Periotest Value related to the SBM selective surface

Table (6, 7) showed the effect of time on the mean changes of the Periotest Values in different time intervals starting from the Immediate till the 1 year follow up period.

There was no statistically significant difference (P > 0.05) through the observation periods: immediate – 3 months, immediate – 6 months, immediate – 9 months for the HA. For the SBM there was no statistical significance for time interval Immediate– 3 months, immediate to 6 months.

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While there was a statistically significant difference (P ≤ 0.05) through the observation periods: immediate – 12 months of the HA selective surface. There was no statistical significance of the observation period of the SBM form immediate to 9 months, Immediate to 12 months.

Effect of time on Periotest Values for the two selective surfaces

3.25

3.5

3.5

1

1.63

1.5

1.6

2.25

2.13

2

1.88

2.5

1.25

Mean depth (mm)

3

HA SBM

0.5 0 immediate - 3 immediate- 6

Immediate-9 immediate-12

Period (months)

Histogram 21: Effect of time on the mean Periotest value (PTV) for the HA and the SBM selective surface implants.

Comparing the changes of the PTV values of each surface in relation to time interval the HA selective surface showed higher degrees of PTV changes than the SBM selective surface except in time interval immediatesix months where the changes in PTV of the SBM was Higher than the HA selective surface (Histogram 21).

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PROBING DEPTH AVERAGE PROBING DEPTHS AROUND THE IMPLANTS Paired t-test was used to compare between average probing depth around the implants. The means, standard deviation values (SD) and results of paired t-test are presented in the following table and curve:

PROBING DEPTH SURFACE

HA

SBM

T-VALUE

P-VALUE

PERIOD

MEAN

SD

MEAN

SD

3 months

1.56

0.44

1.52

0.51

0.251

0.809

6 months

1.73

0.75

1.77

0.91

-0.309

0.766

9 months

1.67

0.53

1.48

0.43

1.029

0.338

12 months

1.71

0.6

1.62

0.41

0.362

0.728

Table 8: Probing Depth readings comparing the HA and the SBM selective surface media

There was no statistical significant difference (P > 0.05) between implants with HA and implants with SBM selective surface through out the observation periods.

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Comparison between probing depth measuremetns for the two surfaces

1.67

1.731.77

1.6 1.55

1.52 1.56

1.5 1.45

HA SBM

1.48

Mean depth (mm)

1.7 1.65

1.62 1.71

1.8 1.75

1.4 1.35 1.3 3

6

9

12

Period (months)

Linear Histogram 22: The Probing depth of the HA and The SBM selective surface media

The mean Probing depth readings for all patients of HA and SBM selective surfaces observed from three months showed similar values for both surfaces. At six months the SBM had higher probing depth by nine month the reading decreased to be in reverse relation with the HA selective surface and maintained with a slight increased in probing depth by the end of the observation period (Linear Histogram 22).

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Comparision of Probing Depth Measurments between the two surfaces

2.215

2.5 2

HA SBM

1.8

1.5

2.415

2.95 3.15

3

2.15 1.95

Mean bone height (mm)

3.5

1 0.5

3

6

9

0

0 12

Period (months)

Linear Histogram 23: Patient One, The Probing depth of the HA and The SBM selective surface media.

Patient one demonstrated the probing depth readings for the HA and the SBM selective surfaces at three and six month both surfaces had similar readings. At nine month the probing depth of the SBM selective surface was highly reduced than the HA selective surface. By twelve months the probing depth of both surfaces had approximated values (Linear Histogram 23).

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Comparision of the Probing Depth Measurments between the two Surfaces

3.3

3 3.3

3.3

2.6

2.5 2.6

Mean bone height (mm)

3

3 3.3

3.5

2

HA SBM

1.5 1 0.5 0 3

6

9

12

Period (months)

Linear Histogram 24: Patient Two, The Probing depth of the HA and The SBM selective surface media.

Patient two, the mean probing depth of the HA and the SBM selective surfaces showed similar readings though out the observation period, with a slight deviation in three and twelve months in relation to the HA selective surface. (Linear Histogram 24)

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Comparision of the Probing Depth Measurments between the two Surfaces

1.23 1.495

1.6

1

1.0651.23

1.2

0.915 1.15

1.15 1.38

Mean bone height (mm)

1.4

0.8

HA SBM

0.6 0.4 0.2 0 3

6

9

12

Period (months)

Linear Histogram 25: Patient Three, The Probing depth of the HA and The SBM selective surface media.

Patient three, the probing depth of the HA and the SBM selective surfaces showed approximation in readings for three, six and nine months. By twelve months the probing depth of the SBM increased and reversed its relation with the HA selective surface (Linear Histogram 25).

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Comparision of the Probing Depth Measurments between the two Surfaces 2 1.8 1.3

1.3 1.45

1

1.6

1.2

1.3

1.4

1.65

1.6

1.3

Mean bone height (mm)

1.8

HA SBM

0.8 0.6 0.4 0.2 0 3

6

9

12

Period (months)

Linear Histogram 26: Patient Four, The Probing depth of the HA and The SBM selective surface media.

Patient four demonstrated the probing depth of the HA selective surface that showed a constant depth throughout the observation period in relation to the SBM selective surface (Linear Histogram 26).

Comparision of the Probing Depth Measurments between the two Surfaces 2

0.8

1.8

1

1.3

1.2

1.8

1.4

1.3

1.3 1.55

1.6

1.08 1.3

Mean bone height (mm)

1.8

HA SBM

0.6 0.4 0.2 0 3

6

9

12

Period (months)

Linear Histogram 27: Patient Five, The Probing depth of the HA and The SBM selective surface media.

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Patient five showed the mean Probing depth readings for the HA and the SBM selective surfaces. At three and six months both surfaces had increased depth, by nine months the HA selective surface increased. At twelve months both surfaces maintained constant depth (Linear Histogram 27).

EFFECT OF TIME ON PROBING DEPTH

Paired t-test was used to study the effect of time on probing depth of implants with Hydroxyapatite (HA) selective surface and the Selective Blasting Media (SBM). The means, standard deviation values (SD) and results of paired t-test are presented in the following tables and curves:

Probing depth of the HA OBSERVATION

MEAN

PERIODS

CHANGE

3 months - 6 months

-0.17

6 months – 9 months

SD

T-

P-

VALUE

VALUE

0.43

-1.089

0.312

0.06

0.39

0.439

0.674

9 months – 12 months

-0.04

0.21

-0.529

0.613

3 months – 12 months

-0.15

0.37

-1.094

0.310

Table 9: Effect of time on Probing depth related to the HA selective surface

Probing depth of the SBM OBSERVATION

MEAN

PERIODS

CHANGE

3 months - 6 months

-0.25

6 months – 9 months

SD

T-

P-

VALUE

VALUE

0.2

-1.257

0.249

0.29

0.63

1.321

0.228

9 months – 12 months

-0.15

0.41

-1.010

0.346

3 months – 12 months

-0.1

0.35

-0.832

0.433

Table 10: Effect of time on Probing depth related to the SBM selective surface

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Table (9, 10) showed the mean changes of the probing depth of the HA and the SBM over the different period of time. There was no statistically significant difference (P > 0.05) throughout the observation period for both materials.

CORRELATIONS

BETWEEN LENGTH OF THE GOLD BAR AND

CHANGES IN CRESTAL BONE HEIGHT BETWEEN IMPLANTS

Pearson’s Correlation Coefficient was used to determine significant correlations between bar length and crestal bone height. The results are presented in the following table and curve: RADIOGRAPH

CORRELATION

P-VALUE

COEFFICIENT (R)

Periapical

-0.178

0.241

Table11: Correlation of the length of the bar and the crestal bone height

The correlation between the bar length and the crestal bone height between the implants showed negative correlation that was statistically non significant (P>0.05). (Table 11)

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Correlation between peripheral bone height and bar length (Periapical radiograph)

Peripheral bone height (mm)

14 12 10 8 6 4 2 0 0

5

10

15

Bar length (m m )

Linear Histogram 28: Correlation of the length of the bar and the crestal bone height

Negative poor correlation observed between the length of the bar and the crestal bone loss between the implants. (Linear histogram 28) CORRELATIONS BETWEEN PERIOTEST AND CHANGES IN MARGINAL BONE HEIGHT

Pearson’s Correlation Coefficient was used to determine significant correlations between Periotest and marginal bone height. The results are presented in the following table and curve: RADIOGRAPH

CORRELATION

P-VALUE

COEFFICIENT (R)

Periapical

-0.171

0.191

Table 12: Correlation of the Periotest values and the marginal bone changes related to the implants

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A negative correlation between the Periotest and the marginal bone height mesial and distal to the implants was observed that was statistically non significant (P>0.05) (Table 12)

Correlation between marginal bone height and Periotest (Periapical radiograph)

Marginal bone height (mm)

14 12 10 8 6 4 2 0 -8

-6

-4

-2

0

2

Periotest

Linear Histogram 29: Correlation of the Periotest values and the marginal bone changes related to the implants

Negative poor correlation observed between the length of the bar and the marginal bone loss between the implants. (Linear Histogram 29)

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PATIENT ONE

Fig (31) Patient one intact ridge

Fig (32) Patient one final restoration

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Fig (33) Patient one preoperative panorama

Fig (34) Patient one preoperative panorama with surgical indicating steel balls

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Fig (35) Patient one, one year follow up.

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PATIENT TWO

Fig (36) Patient two, intact ridge

Fig (37) Patient two, final restoration.

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Fig (38) Patient two preoperative panorama

Fig (39) Patient two preoperative panorama with steel balls

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Fig (40) Patient two one year follow up

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PATIENT THREE

Fig (41) Patient three intact ridge

Fig (42) Patient three final restoration

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Fig (43) Patient three pre operative panorama

Fig (44) Patient three pre operative panorama with steel balls

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Fig (45) Patient three post operative panorama

Fig (46) Patient three one year follow up

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PATIENT FOUR

Fig (47) Patient four preoperative intact ridge.

Fig (48) Patient four final restoration.

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Fig (49) Patient four preoperative panorama

Fig (50) Patient four preoperative panorama with steel balls

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Fig (51) Patient four one year follow up

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PATIENT FIVE

Fig (52) Patient five intact ridge

Fig (53) Patient five final restoration

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Fig (54) Patient five preoperative panorama with steel balls

Fig (55) Patient five one year follow up

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DISCUSSION DISCUSSION OF METHODOLOGY Only male patients from the out patient clinic of Ain Shams University were included in this study. The patient's age ranged from 45 to 68 years old with an average age of 56 years. Female patients were excluded from the study to avoid any fluctuation in bone changes due to lack of hormones or hormonal imbalance remarked at this range of age.176-177 Patients were subjects for blood analysis and fasting sugar blood level to eliminate the chance of Diabetes which may alter the rate of bone resorption and may change the pattern of healing.178 More over smokers were excluded from the study due to the effect of nicotine on the peripheral circulation and soft tissue healing.179-180 Complete edentulous patients chosen for the study had good ridge relationship to avoid abnormal forces on the implant, patients only with angle class I classification were included in the study and all patients with parafunctional habits were excluded.181 Inter arch distance were measured by means of a curved campus to identify the available intermaxillary distance. The mandibular overdenture required more than 12mm of space between soft tissue and the occlusal plane, in other words 15mm from bone level to occlusal plane for the bar attachments and teeth.79-182 The role of Oral hygiene measures were emphasized to the patient as it helped in the success of the implant therapy. Patient who do not comply with oral hygiene instructions lead to plaque deposition, increase in

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gingival bleeding, which may lead to periimplantitis followed by implant failure.183 All patients filled a diagnostic sheet with complete medical and dental history with written consent for the surgical and post surgical procedure performed by the operator giving full agreement for the steps carried out.184 Denture construction was carried with high impact strength acrylic resin with long cycle processing technique to give much strength to the denture base when it is modified to accept the clips of the bar. The teeth used with the denture were a cross linked acrylic resin teeth to act as an impact reducing agent and increase its duration in the patient's mouth due to its high wear resistance over normal acrylic teeth.185The occlusion of the constructed denture was a lingualized occlusal form that provided better chewing efficiency than zero degree occlusal form in implant overdentures.186-187 In this study the protocol for a successful implant was one that demonstrated osseointegration, and optimal position of the implant for the fabrication of an aesthetic and functional restoration as suggested by Smith and Zarb.188 Ideal placement facilitated the establishment of favourable forces on the implants and the prosthetic components and ensured an aesthetic outcome.

Therefore a duplicate of the patient's denture was fabricated to act as a radiographic and surgical stent after modification. The stent was fabricated of transparent acrylic to see the tissues and pressure areas. The radiographic stent was drilled to contain four halls to fit four 0.5 inch diameter balls to reveal the degree of magnification of the panoramic radiograph and to define the site of vital structures as the mental Š2006 Mireille Wassef

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foraminae and the inferior dental canal as suggested by Verde and Morgano 189 and Kopp et al.190 In literature there are other methods for radiographic marking, as Gutta Percha used to identify implant position.191-192 Also later barium sulphate was incorporated into the acrylic resin templates.193-194-195 A radiographicsurgical template (RST) can be used to illustrate the final result and the procedures needed to accomplish it. Radiographic templates commonly were converted into surgical templates by removing the markers and creating a channel in the plastic base.196 In this study implants not less than 10mm were used which is in accordance with the guidelines of immediate loading.79-197 Regarding the fact that there would be a crestal bone loss on the first year of an average of 1.5 mm and 0.3 mm at the following year

198-199

to preserve a

reasonable width of anchorage for the bone/implant interface. the prime concerns of immediate loading protocol was the establishment initial stability79-200 to eliminate micromovement,70-73-74 that might be the main cause for implant failure and not the implant loading per-se, the most maximum torque of about 55-65 Ncm indicated the level of initial stability to ensure the implant success.201 In this study the distance between the first implant insertion and the mental foramen was at least 2mm to avoid any anterior looping of the nerve and 2-3mm were left, from the marking of the panoramic radiograph as suggested by Misch.202 The interforamina area of the mandible was selected for implant insertion due to the absence of any vital structure that may be injured during implant insertion. The optimal bone density in this area would also

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enhance its selection over the posterior mandible as suggested by Salama et al.76 and Misch et al.82 The use of external and internal irrigation dissipates heat to the implant osteotomy site reducing the harmful effect to the bone as suggested by Hoking et al 37and Benington et al.203 Although Benington et al.54 and Sutter et al204 studies suggested no significance in using both systems it is either internal of external irrigation, but in this study the use of both not only helped in heat dissipation but also in the debridement inside the osteotomy site.

Paralleling device was used in this study to ensure paralleling of the implant to each other and to avoid any tipping forces induced on the implants when it lacks parallelism. This is in accordance with other studies by Preiskel205 and Landa et al206 which advocated that implants planned for use as overdenture abutments are placed parallel to each other to obtain predictable attachment retention and complete seating of the restoration and to prevent premature wear of components.

Healing caps were used during the fabrication of the bar to assist for proper tissue healing around the necks of the dental implants.

Screw type implants were used in this study as researches by Ericson et al207 and Piatelli et al208showed that its geometry enhanced better initial stability and better bone implant interface as well as better transmission of compressive forces to the bone which will enhance osseointegration.

In this study two selective surfaces were used the HA and the SBM selective surfaces. Since the presence of surface roughness on the body of the implants increase the surface area in which the Bone Implant Contact (BIC) also increases which may lead to greater area of osseointegration.4579

It was also found that the rough surface ( Dual Acid Etching) of the

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implants enhances the gene expression of the surrounding cells to form more collagen which enhances greater BIC than the smooth surface in 2 to 4 weeks after implant insertion this may indicate that with rough surface we can predict the treatment option of immediate

or early

loading.33-209-210 To ensure good oral environment post operative medications were used. The use of chlorhexidine mouth wash enhanced soft tissue regeneration in absence of infectious elements as the chlorhexidine have an antimicrobial effect to the organisms in the oral cavity.36-211-212-213 To avoid any discrepancies in the solder joint, Duralay*

a methyl

methacrylate resin was used to solder the gold Hader bar to the abutments direct in the patient's mouth, and the degree of polymerization shrinkage was decreased to the minimal by using a very thin layer of the Duralay between gold bar and gold copings.214 It had been emphasized by Branemark et al.215 that implant-supported prostheses should fit passively on the implants and/or abutments nevertheless; all the impression techniques currently used have shown a variable degree of inaccuracy as discussed by Lorenzoni el al.216 and Carr.217

Inaccuracies introduced

during impression making, laboratory analog placement, and prosthesis fabrication cause misfits, which leads to uneven force distribution and possible prosthesis complications such as prosthesis and abutment screw loosening and occlusal inaccuracy as mentioned by Worthington et al.218 and Brunski. 219 Since the implant supported overdenture should rotate around the clip attachment and the bar to ensure tissue-word movement while function.182 The denture fitting surface was properly modified to ensure

*

Reliance Dental Mfg Co, Worth, Ill

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proper rotation of the prosthesis around the implant. An acrylic stent was fabricated to ensure the proper repositioning of the Rinn film holder making it easy to reproduce the same position of the holder over and over through out the follow up procedure. 34-220-221 Since Rinn holder had proven its accuracy in literature to be used with the paralleling technique and standardization of periapical radiographs for the follow up period that would last for twelve months. 169-170-160 The panoramic radiograph was used in this study. But the measurements were not in accordance with that of the periapical radiograph. Therefore the results were limited to Periapical radiographic readings which showed more accurate findings.

With an implant the probing depth goes beyond the sulcus and reaches closer to the bone unlike probing a normal tooth with the periodontal ligament.133-222 Therefore concluded from the studies the probing depth signifie the level of the crestal bone as it is the supporting structure of the gingiva. As long as the crest of the ridge is present there would be minimum alteration of the gingival sulcus.140-141-142 Since

the

radiograph

could

not

determine

the

implant

osseointegration,164 the Periotest was used in this study.

This in

accordance with many researches which proved the efficiency of this device to evaluate the damping power of the implants as it represents the anchorage of the implant to bone and accordingly signifies the degree of clinical osseointegration. 93-95-97-158-197

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DISCUSSION OF RESULTS The patients receiving the treatment were satisfied both clinically and morally. The prosthesis met both function and aesthetics although one patient lost two implants in the first month of restoration from poor compliance to oral hygiene measures and antibiotic regimen that maintain the successful results.124 The remaining two implants gave satisfactory results in both function and appearance and the patient was satisfied through the remaining period of the follow up.

The bone undergoes a series of catabolism and anabolism, the balance of these processes keeps its health. Since in the presence of increased level of catabolism over anabolism there is more bone reduction which was observed during the first three months of immediate loading. This may be explained on the basis of an inflammatory reaction due to the surgical procedure and mechanical load on the implant. When the mechanical load is within the biological range the bone responds to this load by increasing anabolism resulting in increase bone density and slight increase in bone height, which was observed in this study at nine and twelve months. This is in agreement Romanos et al.106 Rubin and Lanyon223-224 who concluded that immediate loading seems to increase the ossification of the alveolar bone around endosseous implants and showed that mechanical stimulation had the potential to enhance bone formation and remodeling around dental implants.

The immediate loading of dental implants in this study showed high rate of success (95%). The loss of two implants in one patient can be attributed to improper compliance of the patients to maintenance and care criteria at the surgical stage, more than it can be attributed to loading since the other two implants carried the load of four and were Š2006 Mireille Wassef

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successfully maintained through the experimental period. This was in accordance with several studies; which proved the effectiveness of immediate loading over delayed loading, with a high rate of success in the presence of implants with selective surfaces hence enhancing the immediate loading procedure.

Chiapasco et al93 and Romeo et at95 studied The success rate of the immediate loading in relation to the delayed loading and concluded that the immediate loading protocol didn’t have any detrimental effect on osseointegration, and conversely, this method significantly shortened the duration of treatment with relevant satisfaction for the patients.

Although Chiapasco and Gatti98 in another prospective study compared the success rate of both protocols immediate and delayed over more than eight years of follow up, the results obtained was in favour of the delayed loading protocol and they related there results to only two implant systems and recommended further research to include more than several implant systems.

Ibanez and Jalbout94 concluded that a high success rate can be achieved when implants with a hybrid surface, machined/acid-etched, were immediately loaded within 48 hours after surgical placement in the maxilla and the mandible.

Stricker et al99 agreed that the presence of roughened surfaces on the implant body enhanced the rate of success especially when used with the immediate loading protocol.

The presence of the proper selective surfaces in relation to bone would accordingly enhance osseointegration of implants. In the present study on comparing the pattern of crestal bone changes in relation to two selective surfaces HA and SBM selective surfaces it was observed that there was Š2006 Mireille Wassef

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no major difference in crestal bone changes in relation to the two surfaces. The SBM surfaces showed lesser bone reduction during the follow up period.

Due to the small sample size the reaction of each patient to the selective surfaces was observed separately. Comparing the readings of pattern of bone changes for each patient it was noticed that the bone responded similarly to both materials in most instances as shown by the linear histograms which went in a parallel fashion or even coincided with each other for both mesial and distal surfaces. Slight deviation was observed in patient one where there was a difference in bone reaction at six months. The SBM showed apparent more bone loss but by nine months the remodeling of bone showed increased height of crestal bone even more than that observed for the HA surfaces. This observation was augmented by the Periotest readings which was an indication of the degree of damping of the implant in bone. The Periotest readings showed lesser negative values when bone loss increased and a direction toward higher negative values when bone remodeling around the implants was increased.

The results were in accordance with the results of Taba et al123 who evaluated radiographically implants with SBM and HA coatings. They concluded that surface treatments that add roughness to the implant showed numerically higher bone density when compared with machined surfaces. The findings of radiographic density analysis suggested that the soluble blasting media-treated surface (SBM) provides a greater bone density at the peri-implant region more than the HA selective surface.

In the current study observing the percentage of crestal bone changes between the HA and the SBM selective surfaces, the HA showed higher degree of percentage changes over the course of the observation period Š2006 Mireille Wassef

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than the SBM. It was statistically non significant (P>0.05) except at Immediate-nine months period. The increased percentage changes for the HA might be related to the increased degradation of the surface coating.

This comes in accordance with Proussaefs113 who suggested that Hydroxyapatite (HA) coatings can resist degradation in contact with bone but may be more prone to dissolution in contact with soft tissue.

Analyzing the mean Periotest values for SBM and HA implants through out the follow up period, significant increase in the mean of negative values was observed, denoting more damping and increase in bone density around implant with mechanical and functional loading. However the two surfaces did not show the same amount of damping since the HA implants showed higher initial stability than the SBM implant denoted by the Periotest values, which was statistically significant at six months. The Periotest values for SBM and HA reached similar reading by the end of the observation period which indicated that the SBM surface was able to enhance bone apposition near the implant surface.

This was in accordance with result of Novaes et al.120 on an animal study model. There study included the histomorphometric changes of bone implant contact for four different implants surfaces including HA and SBM surfaces and observed that the SBM had higher bone implant contact percentage than HA in this study.

Niznick30 suggested that sharpness of the threads of implants with SBM coating was less than that of HA coatings which explained the higher degree of initial stability related to the HA implants.

Several authors suggested the increase of the insertion torque as a reliable mean for the implant initial stability. 201-.225-226

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The probing depth followed a fixed land mark point in the suprastructure to standardize the readings as suggested by Salvi and Lang.121 The probing depth showed minimal gingival recession with no statistical significant difference between mean pocket depth values for the two surfaces. This might be due to the minimal bone changes occurring around the implants in the first year that came in accordance to the success criteria of dental implants.147 The effect of time on both materials in the probing depth showed negative values which confirmed the radiographic findings, which showed the increase in bone height from six to twelve months observation period, denoting a remodeling process in favor to the selective surfaces.

This is in accordance with the studies of Abuelroos34 Romanos et al106 El Hadary220 Rubin and Lanyon223-224 who all agreed on the remodeling process occurring during implant healing period that may enhance more bone formation than resorption.

The correlation between the amount of the crestal bone formation and the length of the bar was very week, although there was a negative correlation between them. Which meant, as the length of the bar increased the amount of bone formation was decreased. Therefore it is advised to decrease the length of bar to the biological limit between implants with a minimum of 3mm as recommended by Smith and Zarb188 in their criteria for success of osseointegrated endosseous implants.

In this study a week negative correlation between the Periotest values and the marginal bone height changes was observed. The negative correlation meant that the Periotest value increased in a positive direction when the bone height decreased.

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In both correlations the relation was week due to small sample size as statistically these correlations are not significant unless the sample size is increased.

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SUMMARY AND CONCLUSION

SUMMARY Twenty endosteal root form paragon implants were inserted in the anterior mandible region interforamina area for five completely edentulous patients to retain a mandibular overdenture. Each patient received four surface treated implants with two selective surfaces the Hydroxyapatite HA and the Soluble Blasting Media SBM.™ The implants were immediately loading after insertion and patients were subject for observation period of twelve months during which a series of radiographic pictures, probing depth and Periotest values (PTVs) were taken for the assessment of the level of bone resorption and apposition related to the implants.

The clinical evaluations using the diagnostic means were on the interval of three months each and all reading were recorded and tabulated for the statistical analysis. Readings were recorded immediately after implant insertion with the intervals of three months, six months, nine months and twelve months period.

The radiographic readings were processed to the computer with the use of the DIGORA Demo soft ware; results were retrieved and tabulated for further statistical analysis.

The crestal bone height for both surfaces mesial and distal to the implants demonstrated higher level of percentage bone changes with the SBM implants than the HA implants which indicated that the SBM selective surface might promote more bone formation around the surfaces of the implants. Š2006 Mireille Wassef

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The Periotest values for both surfaces showed lesser negative values for the SBM implants than the HA implants compared from the start till the end of the observation period which indicated better osseointegration and bone density around the implant for the SBM implants in comparison to the HA implants.

The probing depth of both surfaces showed similar results and confirmed the radiographic results.

CONCLUSIONS AND RECOMENDATIONS The immediate loading for dental implants with selective surfaces inserted in the inter symphesial region connected with a gold Hader Bar is a successful procedure that decreased the time for the patient to obtain a final restoration satisfying both esthetical and functional problems.

Proper patient selection with good motivation, free of any systemic diseases, parafunctional habits, smokers and adequate bone height increase the success rate with the immediate loading protocol The initial stability of dental implants confirmed by the Periotest readings during implant insertion favors the loading conditions and increase in the insertion torque enhance the initial stability.

The Periotest Values showed reliable results and confirmed with the radiographic readings the osseointegration of the dental implants with selective surfaces.

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