Edentulous Mandible

Immediate Loading With Mini Dental Implants in the Fully Edentulous Mandible Mi-Ra Ahn, DDS,* Kyung-Mi An, DDS,† Jung-Hwan Choi, DDS,‡ and Dong-Seok Sohn DDS, PhD§

uccessful oral rehabilitation with dental implants for partially or fully edentulous patients has been reported.1–3 Regardless of this success, a 3- to 6-month healing period is usually required to get osseointegration, depending on bone quality. In this period, premature loading to the dental implants is prohibited to allow for osseointegration.4,5 In addition, no removable prosthesis is used as long as possible because premature loading can disturb the healing at the site of guided bone regeneration or bone graft.6 However, patients often complain of diet difficulties and unaesthetic appearances during the healing period between implant placement and final prosthesis because they cannot wear a denture. To solve these patients’ complaints, provisional mini dental implants can be placed between final implants or at the site of bone grafts. Provisional mini dental implants provide immediate overdenture or fixed prosthesis support after final implant placement. This technique requires minimal additional time and is economic because the patients’ old dentures are used as immediate temporary prostheses.

The purpose of this article is to evaluate the efficacy of 27 provisional mini dental implants, which were loaded immediately for 11 patients.

S

*Resident, Department of Oral and Maxillofacial Surgery, Daegu Catholic University, Daegu, Republic of Korea. †Resident, Department of Oral and Maxillofacial Surgery, Daegu Catholic University, Daegu, Republic of Korea. ‡Resident, Department of Oral and Maxillofacial Surgery, Daegu Catholic University, Daegu, Republic of Korea. §Associate Professor, Chair. Department of Oral & Maxillofacial Surgery, Daegu Catholic University, Daegu, Republic of Korea.

ISSN 1056-6163/04/01304-367 Implant Dentistry Volume 13 • Number 4 Copyright © 2004 by Lippincott Williams & Wilkins DOI: 10.1097/01.id.0000148560.65514.3d

The use of immediate loaded prostheses is not recommended for at least 2 weeks to prevent implants from premature loading. In addition, immediate removable prostheses are negated for at least 4 weeks at the site of guided bone regeneration or bone graft. However, patients are often not pleased with limited diets and the unaesthetic appearance during the healing period without a denture between implant placement and final prosthesis. Mini dental implants provide stable and esthetic

temporary prostheses immediately after implant placement and bone grafts. The use of mini dental implants is simple and cost effective because the patient’s old denture is used as a provisional prosthesis.

This article shows the success of 27 mini dental implants that were placed for 11 mandibular fully edentulous patients. (Implant Dent 2004; 13:367–372) Key Words: loading, dental implants, temporary prosthesis

MATERIALS

sorption. The depth of the osteotomy was limited to half of the implant length to get the primary stability of mini dental implants.

Mini implants were self-tapped and placed with a finger driver manually.

The final seating of mini implants was performed with a ratchet. Mini implants were unscrewed in approximately 180° to 360° counterclockwise direction in the very dense bone (type I density) and rescrewed to a final position. This selfadvancing step was repeated several times to prevent mini dental implants from fracture in the very dense bone.

Two to four implants were placed depending on the type of prosthesis. Two implants were placed for an implantsupported overdenture, and three to four implants were placed for a fixed prosthesis (nontissue support type).

The incision was sutured in a standard manner. A sterile rubber dam was punched out with a rubber dam puncher and placed over the surgical site to prevent the suture area from sticking to the self-curing rebase materials (Tokuso Rebase; Tokuyama Dental Corp., Tokyo, Japan) or self-curing pattern resin

AND

METHODS

Twenty-five mini dental implants (IMTEC Corp., OK) and two mini drive-lock implants (Intra-Lock International Inc., FL) were placed in the fully edentulous mandible of 11 patients (4 men and 7 women) ranging in age from 41 to 73 years (average, 52.9 years) from April 2002 to September 2003. The diameter of the mini dental implant was 1.8 mm. The diameter of two mini drive lock implants was 2.0 mm. The length of mini dental implants that were placed is 13 to 18 mm (average: 15 mm) (Table 1).

Surgical Procedure

All final and provisional mini dental implants were placed in the mandible under local anesthesia. Crestal incision was made to expose the bone. A 1.2-mm pilot was the only drill for osteotomy of the implant site to place provisional mini dental implants. External irrigation with normal saline was supplied.

The osteotomy of mini dental implant was at least 2 mm away from the site of the final implant site to prevent the final implant from early bone re-

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Table 1. Average Diameter, Length, and Loading Period of Mini-implants in Current Study

Case No. 10: Immediate Fixed Prosthesis Using Four Mini Dental Implants

Case Age No. of Type of Diameter Length No. (yrs)/Sex MI Prosthesis (mm) (mm)

This 41-year-old male patient presented with a fully edentulous maxilla and mandible (Fig. 2A). Transitional maxillary and mandibular full dentures were fabricated and delivered before implant surgery. The patient wanted an immediate prosthesis after placement of full implants. Bone grafting was performed in the bilateral posterior extraction defects after the placement of full implants and simultaneous four mini dental implants (Fig. 2B, C). His old denture was modified and adapted to the head of provisional mini dental implants. The fixed prosthesis was cemented in the square head of the mini dental implants in the mandible on the surgical day (Fig. 2D). The tissue side of the provisional fixed prosthesis was reduced to avoid premature pressure to the site of bone grafting and final implants in both posterior areas. The uncovering of final implants was performed after a 5-month healing period. Good bone regeneration and osseointegration of the final implants were seen (Fig. 2E). No permanent implants showed failure. A final implant-supported fixed prosthesis was cemented 6 weeks later (Fig. 2F, G).

1 73/F 2 63/M 3 47/F 4 66/F 5 47/M 6 49/M 7 65/F 8 52/F 9 56/F 10 41/M 11 43/F Average 52.9

2 2 2 2 2 2 2 3 2 4 4

R R R R R R R F R F F

1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.9 1.82

Date of Insertion

Date of Loading Period Removal (week)

13 5/17/2001 11/14/2001 15 6/20/2001 1/11/2002 15 4/30/2002 10/5/2002 15 6/17/2002 10/21/2002 15 11/22/2002 2/19/2003 15 11/13/2002 6/25/2003 15 2/24/2003 8/4/2003 15 4/23/2003 9/5/2003 18 4/18/2003 11/4/2003 13 5/9/2003 10/29/2003 15 9/17/2003 2/13/2004 14.9

16 29 17 18 12 36 24 18 27 14 20 21.2

MI, mini implant; R, removable type; F, fixed type.

(GC Corp., Tokyo, Japan). The O-ring and metal housing were seated on the O-ball head of the implant for an implant-supported overdenture. The patients’ old dentures were prepared to make the space for the O-ring and metal housing (or square head of the mini dental implant for a fixed prosthesis). Selfcuring rebase materials or self-curing pattern resin was added to the tissue side of the newly adapted denture and placed on the O-ball head of the mini dental implants (or square head of the mini dental implant for a fixed prosthesis).

Excessive rebasing material was trimmed, and the newly adapted denture did not make any premature pressure to the final implants or the site of bone grafting. After the curing of the rebasing material, the occlusion and retention of the temporary prosthesis were checked and the denture was delivered to the patient on the surgical day.

CASE REPORTS Case No. 6: Immediate Removable Prosthesis Using Two Mini Dental Implants

A 49-year-old male patient had used his old ceramic metal bridge as a removable prosthesis. When this bridge was removed, soft tissue was overgrown and a concavity of extraction defect was seen (Fig. 1A, B). An extraction bony defect was seen in the computed tomogram (Fig. 1C). An overdenture that was supposed to be supported by two mini dental implants and bone graft was planned.

After removal of this ceramic metal bridge, a transitional full denture was delivered to allow for healing of soft

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tissue at the extraction socket. Implant surgery was performed 4 weeks later.

Two final implants (Endopore; Innova Corp., Toronto, Ontario, Canada) were placed in both mandibular canine areas.

The osteotomy for mini dental implants was performed between two final implants. The osteotomy was prepared 2 mm away from these implants. Allograft (irradiated cancellous bone and marrow; Rocky Mountain Tissue Bank, Aurora, IL) was grafted in the extraction defect (Fig. 1D). His old denture was modified and adapted to the O-ball head of the mini dental implants (Fig. 1E, F). No premature pressure to the site of the bone graft and the final implants was verified. The retention and support of this prosthesis was more favorable than the old denture. Mini dental implants were removed and the uncovering of the final implants was performed after a 5-month healing period. Favorable bone regeneration and no bone resorption around the mini implants were seen (Fig. 1G). The denture was newly adapted for overdenture abutments (Locator; Innova Corp.) that were placed in the final implants on the uncovering day for continuous denture use.

A final prosthesis using two ZAAG locator attachments (Zest Anchors Inc., CA) was delivered 6 weeks later (Fig. 1H). This patient was very satisfied with the immediate provisional removable prosthesis supported by mini dental implants because he had used his denture from the first surgical day to the day of the final implant-supported prosthesis.

IMMEDIATE LOADING WITH MINI DENTAL IMPLANTS

IN THE

RESULTS Twenty-seven provisional mini dental implants were placed in the anterior mandible, and 26 mini implants remained stable and functioned from the first surgical day to the uncovering day of the final implants. One mini implant was fractured during placement. The average functioning time was approximately 21 weeks. All patients were satisfied with immediate implantsupported overdentures or fixed prostheses supported by mini implants throughout the healing period in the mandible. Mini implants did not disturb the osseointegration of the final implants and bone regeneration at the site of bone grafting. All patients reported no pain or discomfort with these immediate temporary prostheses. No bone resorption was observed at the exposure of final implants.

FULLY EDENTULOUS MANDIBLE

Fig. 1. (A) Intraoral view of the healed socket after removal of a ceramic metal bridge. (B) Fixed prosthesis that the patient used as a removable prosthesis. (C) Large bony defect in the extraction site. (D) Bone graft and two mini implants and final implants. (E) Modified old denture O-ring and metal housing were placed. (F) Postoperative panoramic radiograph. (G) Good bone regeneration and no bone resorption at mini implant sites after 5 months of loading. (H) Final overdenture using two Locator attachments (Innova Corp., Toronto, Canada).

DISCUSSION The loading of implants should be avoided until completion of implant osseointegration.2,3,7 In addition, trauma caused by immediate loading to the site of a bone graft can cause failure of bone regeneration. Also, patients may have a limited diet and limited social activity in the absence of a temporary prosthesis during the healing period.

The use of provisional mini dental implants offers many advantages to both patients and surgeons. The use of mini dental implants provides patients with

an immediate removable denture or fixed prosthesis after implant placement.8,9 This immediate temporary prosthesis using provisional mini implants can solve speech problems, unaesthetic appearance, and mastication problems during the healing period.10,11 In addition, mini implants do not disturb the osseointegration of final implants and the regeneration of a bone graft.8 –12 Mini dental implants are cost effective because the patients’ original denture is modified and used as a provisional prosthesis. The surgical time for the place-

ment of mini implants is minimal. Two mini implants are necessary for an immediate implant-supported overdenture in the mandible. Three to four mini implants are required for an immediate fixed prosthesis in the mandible.

For the sake of initial stability of mini implants, the depth of osteotomy should not be drilled to the length of the mini implants. The depth of the osteotomy should be limited to the half-length of mini implants, which will be placed in the anterior mandible because mini implants are self-tapped for the final position with primary mechanical retention. Mini implants should be placed with a finger wrench and ratchet manually to verify initial stability.

Bone density is one of the major determining factors for the high success rate of mini implants.13,14 The high success rate of provisional mini implants was reported in the anterior mandible, but in the maxilla, the high loss of provisional mini implants has been reported.8,10,12 A lower degree of removal torque of transitional implants was required in the maxilla than the mandible because of poor bone density.13 Bone resorption around mini dental implants is possible at the site of poor bone density. Provisional mini dental implants should be placed at least 2 mm away from permanent implants to prevent bone resorption at the site of a final implant.14,15 When provisional mini implants cannot advance within very dense bone, the implants should be unscrewed 180° to 360° at the site of very dense bone, and then manual advancement of mini implants is repeated to prevent the fracture of the provisional mini implant. This procedure is repeated until final seating of mini implants. The fracture of one mini implant that was described in this article happened because of forceful advancement without the repeated unscrewing and advancement of the mini implant in very dense bone.

The use of titanium alloy-based mini implants may be more advantageous than commercially pure titanium-based provisional mini implants to reduce bending or fracture of the implants during the insertion and function of the provisional implants.14

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Fig. 2. (A) Preoperative panoramic photograph showing fully edentulous jaws and bony defects in extraction sockets. (B) Bone grafting in the bilateral posterior extraction defects. (C) Postoperative panoramic radiograph. Four mini dental implants in the mandible and five provisional implants were placed. (D) Immediate provisional fixed prosthesis cemented to mini dental implants. Note the relief of the tissue side to avoid premature pressure to the site of the bone graft and final implants.

CONCLUSION An immediate temporary removable or fixed prosthesis supported by mini implants in the mandible is very advantageous. This prosthesis does not disturb either osseointegration of final implants or the healing of bone grafts. In addition, mini implant-supported prostheses provide immediate mastication and esthetics for patients during the healing period. Two mini implants are recommended for overdentures but three to four mini implants are required for a fixed prosthesis in the mandible.

Disclosure

None of the authors have any financial interest in the mini implants mentioned in this article.

REFERENCES 1. Adell R. Tissue integrated prostheses in clinical dentistry. Int Dent J. 1985; 35:259–65.

2. Albrektsson T, Zarb GA, Worthington P, et al. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants. 1986;1:11–25.

3. Jemt T, Lekholm U. Oral implant treatment in posterior partially edentulous jaws: a five-year follow follow-up report. Int J Oral Maxillofac Implants. 1993;8:635–640.

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4. Branemark PI. Osseointegration and its experimental background. J Prosthet Dent. 1983;50:399–410.

5. Lagawa Y, Ishikawa Y, Nikai H, et al.

Interface histology of unloaded and early loaded partially stabilized Zirconia endosseous implants in initial bone healing. J Prosthet Dent. 1993;69:599–607.

6. Nevins M, Mellonig JT. Implant Therapy: Clinical Approaches and Evidence of Success, vol II. Quintessence Books; 1998:91–97.

7. Piattelli A, Corigliano M, Scarano A, et al. Immediate loading of titanium plasma-sprayed implants: an histologic analysis in monkeys. J Periodontol. 1998; 69:321–327.

8. Krennmair G, Weinla¨ nder M, Schmindinger S. Provisional implants for anchoring removable interim prostheses in edentulous jaws: a clinical study. Int J Oral Maxillofac Implants. 2003;18:582–588.

9. Ravasini T. Immediate provisional implants as abutments for an overdenture in the mandibular edentulous jaw: case presentation. Pract Proced Aesthet Dent.

2002;14:673–677.

10. Leshem D, Mazor Z, Leshem R, et al. A simple technique for fabrication of immediate interim removable prosthesis supported by transitional implants. Implant Dent. 2003;12:227–231.

11. Nagata M, Nagaoka S, Mukunoki O. The efficacy of transitional implants placed simultaneously with implant fixtures. Compend Contin Educ Dent. 1999;20:975–978.

12. Khoury F, Happe A. Interim im-

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IN THE

Fig. 2. (E) Good bone regeneration in the previous extraction defect. (F) Intraoral view of the final implant-supported prosthesis. (G) Panoramic radiograph after cementation of the final prosthesis.

plants in extensive bone transplantation procedure: results of a clinical study. Implantology. 2000;9:375–387.

13. Simon H, Caputo A. Removal torque of immediately loaded transitional endosseous implants in human subjects. Int J Oral Maxillofac Implants. 2002;17:839–845.

14. Sohn DS. Color Atlas, Immediate Loading With Temporary Implants.

Jiseong Publication Co; 2002:116–118.

15. Froum S, Emtiaz S, Bloom M, et al.

The use of transitional implants for immediate fixed temporary prostheses in cases of implant restorations. Pract Periodont Aesthet Dent. 1998;10:737–746.

Reprint requests and correspondence to: Dong-Seok Sohn, DDS, PhD Department of Oral & Maxillofacial Surgery Daegu Catholic University Hospital 3056 – 6 Daemyung 4-Dong Nam-Gu, Daegu, Republic of Korea 705-034 Phone: (53)650-4288 Fax: (53)622-7067 E-mail: dssohn@cu.ac.kr

FULLY EDENTULOUS MANDIBLE

Abstract Translations [German, Spanish, Portugese, Japanese] AUTOR(EN): Mi-Ra Ahn, DDS*, Kyung-Mi An, DDS**, Jung-Hwan Choi, DDS***, Dong-Seok Sohn, DDS, PhD****. * Assistenzarzt, Abteilung fu¨r Gesichts- und Kieferchirurgie, Katholische Universita¨t von Daegu, Republik Korea. ** Assistenzarzt, Abteilung fu¨r Gesichts- und Kieferchirurgie, Katholische Universita¨t von Daegu, Republik Korea. *** Assistenzarzt, Abteilung fu¨r Gesichts- und Kieferchirurgie, Katholische Universita¨t von Daegu, Republik Korea. **** A.O. Professor, Leiter der Abteilung fu¨r Gesichts- und Kieferchirurgie, Katholische Universita¨t von Daegu, Republik Korea. Schriftverkehr: Dong-Seok Sohn, DDS, PhD, Abteilung fu¨r Gesichts- und Kieferchirurgie (Dept. of Oral & Maxillofacial Surgery), Klinik der Katholischen Universita¨t Daegu (Daegu Catholic University Hospital), 3056 - 6 Daemyung 4-Dong, Nam-Gu, Daegu, Republik Korea (Republic of Korea), 705 – 034. Telefon: (53) 650 – 4288, Fax: (53) 622 –7067. eMail: dssohn@cu.ac.kr AUTOR(ES): Mi-Ra Ahn, DDS*, Kyung-Mi An, DDS**, Jung-Hwan Choi, DDS***, Dong-Seok Sohn, DDS, PhD****. *Residente, Departamento de Cirugı´a Oral y Maxilofacial, Daegu Catholic University, Daegu, Repu´blica de Corea. *Residente, Departamento de Cirugı´a Oral y Maxilofacial, Daegu Catholic University, Daegu, Repu´blica de Corea. *Residente, Departamento de Cirugı´a Oral y Maxilofacial, Daegu Catholic University, Daegu, Repu´blica de Corea. **Profesor Asociado, Jefe, Departamento de Cirugı´a Oral y Maxilofacial, Daegu Catholic University, Daegu, Repu´blica de Corea. Correspondencia a: Dong-Seok Sohn, DDS, PhD, Dept. of Oral & Maxillofacial Surgery, Daegu Catholic University Hospital, 3056 – 6 Daemyung 4-Dong, Nam-Gu, Daegu, Republic of Korea, 705– 034.

Tele´fono: (53) 650-4288, Fax: (53) 622-7067.

Correo electro´nico: dssohn@cu.ac.kr

Unmittelbare Belastung mit Mini-Zahnimplantaten im vollkommen zahnlosen Unterkiefer ZUSAMMENFASSUNG: Der Einsatz einer unmittelbar belasteten Prothetik sollte fru¨hestens zwei Wochen nach dem Ersteingriff erfolgen, um die Implantate vor vorzeitiger Belastung zu schu¨tzen. Au␤erdem sind sofort entfernbare Prothesen fru¨hestens vier Wochen nach der Behandlung im Bereich einer gestu¨tzten Knochengewebsregeneration oder Knochentransplantation zula¨ssig. Demgegenu¨ber stehen die Patienten, die ha¨ufig mit den Einschra¨nkungen bezu¨glich Erna¨hrung und una¨sthetischer Optik wa¨hrend des Hei¨ bergangslo¨sung zwischen Implanlungsprozesses unzufrieden sind, wenn ihnen keine U tateinsatz und letztendlicher Protheseanpassung zur Verfu¨gung steht. MiniZahnimplantate bieten hier eine stabile und a¨sthetische Prothesenlo¨sung zum voru¨bergehenden Einsatz sofort nach unmittelbarem Implantierungs- oder Transplantierungseingriff. Mini-Zahnimplantate sind leicht anzuwenden und, da die alte Prothese des Patienten als Provisorium genutzt werden kann, erweist sich diese Lo¨sung auch als kostengu¨nstig. Der vorliegende Artikel beschreibt den erfolgreichen Behandlungsverlauf fu¨r insgesamt 11 Patienten, bei denen im vollkommen zahnlosen Unterkiefer 27 MiniZahnimplantate eingesetzt wurden. ¨ SSELWO ¨ RTER: Belastung, Zahnimplantate, provisorische Prothese SCHLU

Carga inmediata con mini implantes dentales en la mandı´bula totalmente edentulosa ABSTRACTO: El uso de pro´tesis cargadas inmediatamente no se recomienda durante por lo menos dos semanas para prevenir que los implantes sean cargados prematuramente.

Adema´s, las pro´tesis removibles inmediatamente no se deben usar durante por lo menos 4 semanas en el lugar de la regeneracio´n guiada o injerto del hueso. Sin embargo, los pacientes a menudo no esta´n satisfechos con dietas limitadas y una presentacio´n poco este´tica durante el perı´odo de curacio´n sin una dentadura entre la colocacio´n del implante y la pro´tesis final. Los mini implantes dentales proporcionan pro´tesis temporarias estables y este´ticas inmediatamente despue´s de la colocacio´n del implante e injertos de hueso. El uso del mini implante dental es simple y de bajo costo porque la dentadura vieja del paciente se puede usar como pro´tesis provisoria. Este artı´culo muestra el e´xito de veintisiete mini implantes dentales que fueron colocados en 11 pacientes con mandı´bulas totalmente edentulosas.

PALABRAS CLAVES: carga, implantes dentales, pro´tesis temporarias

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AUTORES: Mi-Ra Ahn, Cirurgia˜o-Dentista*, Kyung-Mi An, Cirurgia˜o-Dentista**, JungHwan Choi, Cirurgia˜o-Dentista***, DongSeok Sohn, Cirurgia˜o-Dentista, PhD****. *Residente, Departamento de Cirurgia Oral e Maxilofacial, Universidade Cato´lica de Daegu, Daegu, Repu´blica da Core´ia. **Residente, Departamento de Cirurgia Oral e Maxilofacial, Universidade Cato´lica de Daegu, Daegu, Repu´blica da Core´ia. ***Residente, Departamento de Cirurgia Oral e Maxilofacial, Universidade Cato´lica de Daegu, Daegu, Repu´blica da Core´ia. ****Professor Associado, Chefe do Departamento de Cirurgia Oral e Maxilofacial, Universidade Cato´lica deDaegu, Daegu, Repu´blica da Core´ia. Correspondeˆncia para: Dong-Seok Sohn, DDS, PhD, Dept. of Oral & Maxillofacial Surgery, Daegu Catholic University Hospital, 3056 – 6 Daemyung 4-Dong, Nam-Gu, Daegu, Republic of Korea 705– 034. Telefone: (53) 650-4288, Fax: (53) 622-7067. E-mail: dssohn@cu.ac.kr

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ABSTRACT TRANSLATIONS

Carga Imediata com Miniimplantes Denta´rios na Mandı´bula Totalmente Desdentada RESUMO: O uso de pro´teses carregadas imediatas na˜o e´ recomendado por pelo menos duas semanas a fim de impedir os implantes de carga prematura. Ale´m disso, pro´teses removı´veis imediatas sa˜o negadas por pelo menos 4 semanas no local da regenerac¸a˜o o´ssea guiada ou do enxerto o´sseo. Contudo, os pacientes frequ¨entemente na˜o ficam satisfeitos com dietas limitadas e apareˆncia na˜o este´tica durante o perı´odo de cura sem uma dentadura entre a colocac¸a˜o do implante e a pro´tese final. Miniimplantes denta´rios proporcionam pro´teses tempora´rias, esta´veis e este´ticas, imediatamente apo´s a colocac¸a˜o do implante e dos enxertos o´sseos. O uso de miniimplante denta´rio e´ simples e econoˆmico porque a velha dentadura do paciente e´ usada como pro´tese proviso´ria. Este artigo mostra o sucesso de vinte e sete miniimplantes denta´rios que foram colocados para 11 pacientes mandibulares totalmente desdentados.

PALAVRAS-CHAVE: carga, implantes denta´rios, pro´tese tempora´ria.