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Volume 1, No. 8

NoVember 2009

The Journal of Implant & Advanced Clinical Dentistry

Maxillary Sinus Augmentation Histologic and Histomorphometric Analysis

Single Surgery Comprehensive Gingival Grafting Technique 2H

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The Journal of Implant & Advanced Clinical Dentistry Volume 1, No. 8 • NoVember 2009

Table of Contents

13 Case of the Month Biologic Shaping Daniel Melker

19 JIACD Continuing Education

Management of the Actively Bleeding and Hypovolemic Dental Patient

Dan Holtzclaw, Nicholas Toscano

29 Single Surgery Comprehensive Gingival Grafting Utilizing Palatal Donor Tissue

M. Thomas Wilcko, William M. Wilcko

49 Maxillary Sinus Floor

Augmentation: A Histologic and Histomorphometric Human Grafting Study Comparing Two Anorganic Bovine Bone Minerals Aron Gonshor, Yoon-Je Jang

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The Journal of Implant & Advanced Clinical Dentistry Volume 1, No. 8 • NoVember 2009

Table of Contents

59 Preservation of Buccal Bone

Plate after Immediate Implant Placement/Function with the Flapless Approach: A Case Report Arthur B. Novaes Jr., Rafael R. de Oliveira, Valdir A. Muglia

69 Subperiosteal Dental Implants: A 25 Year Retrospective Survival Evaluation

Antonio T. Di Giulio, Giancarlo Di Giulio, Enrico Gallucci

77 Dental 3D Imaging Centers -

Usage and Findings: Part III – Bifid Canals and Other Deviations of the Inferior Alveolar Nerve

Alan Alan A. Winter, Kouresh Yousefzadeh, Alan S. Pollack, Michael I. Stein, Frank J. Murphy, Christos Angelopoulos

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The Journal of Implant & Advanced Clinical Dentistry Volume 1, No. 8 • NoVember 2009

Publisher SpecOps Media, LLC Design Jimmydog Design Group www.jimmydog.com Production Manager Stephanie Belcher 336-201-7475 Copy Editor JIACD staff Digital Conversion NxtBook Media Internet Management InfoSwell Media Subscription Information: Annual rates as follows: Non-qualified individual: $99(USD) Institutional: $99(USD). For more information regarding subscriptions, contact info@jiacd.com or 1-888-923-0002. Advertising Policy: All advertisements appearing in the Journal of Implant and Advanced Clinical Dentistry (JIACD) must be approved by the editorial staff which has the right to reject or request changes to submitted advertisements. The publication of an advertisement in JIACD does not constitute an endorsement by the publisher. Additionally, the publisher does not guarantee or warrant any claims made by JIACD advertisers. For advertising information, please contact: info@JIACD.com or 1-888-923-0002 Manuscript Submission: JIACD publishing guidelines can be found at http://www.jiacd.com/author-guidelines or by calling 1-888-923-0002.

Copyright © 2009 by SpecOps Media, LLC. All rights reserved under United States and International Copyright Conventions. No part of this journal may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying or any other information retrieval system, without prior written permission from the publisher. Disclaimer: Reading an article in JIACD does not qualify the reader to incorporate new techniques or procedures discussed in JIACD into their scope of practice. JIACD readers should exercise judgment according to their educational training, clinical experience, and professional expertise when attempting new procedures. JIACD, its staff, and parent company SpecOps Media, LLC (hereinafter referred to as JIACD-SOM) assume no responsibility or liability for the actions of its readers. Opinions expressed in JIACD articles and communications are those of the authors and not necessarily those of JIACDSOM. JIACD-SOM disclaims any responsibility or liability for such material and does not guarantee, warrant, nor endorse any product, procedure, or technique discussed in JIACD, its affiliated websites, or affiliated communications. Additionally, JIACD-SOM does not guarantee any claims made by manufact-urers of products advertised in JIACD, its affiliated websites, or affiliated communications. Conflicts of Interest: Authors submitting articles to JIACD must declare, in writing, any potential conflicts of interest, monetary or otherwise, that may exist with the article. Failure to submit a conflict of interest declaration will result in suspension of manuscript peer review. Erratum: Please notify JIACD of article discrepancies or errors by contacting editors@JIACD.com JIACD (ISSN 1947-5284) is published on a monthly basis by SpecOps Media, LLC, Saint James, New York, USA.

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The Journal of Implant & Advanced Clinical Dentistry

Founder, Co-Editor in Chief Dan Holtzclaw, DDS, MS

Founder, Co-Editor in Chief Nicholas Toscano, DDS, MS

Board A Minimally Invasive and SystematicEditorial Approach Advisory to Sinus Grafting Tara Aghaloo, DDS, MD Faizan Alawi, DDS Michael Apa, DDS Alan M. Atlas, DMD Charles Babbush, DMD, MS Thomas Balshi, DDS Barry Bartee, DDS, MD Lorin Berland, DDS Peter Bertrand, DDS Michael Block, DMD Chris Bonacci, DDS, MD Hugo Bonilla, DDS, MS Gary F. Bouloux, MD, DDS Ronald Brown, DDS, MS Bobby Butler, DDS Donald Callan, DDS Nicholas Caplanis, DMD, MS Daniele Cardaropoli, DDS Giuseppe Cardaropoli DDS, PhD John Cavallaro, DDS Stepehn Chu, DMD, MSD David Clark, DDS Charles Cobb, DDS, PhD Spyridon Condos, DDS Sally Cram, DDS Tomell DeBose, DDS Massimo Del Fabbro, PhD Douglas Deporter, DDS, PhD Alex Ehrlich, DDS, MS Nicolas Elian, DDS Paul Fugazzotto, DDS Scott Ganz, DMD Arun K. Garg, DMD David Guichet, DDS Kenneth Hamlett, DDS Istvan Hargitai, DDS, MS Michael Herndon, DDS Robert Horowitz, DDS Michael Huber, DDS

Richard Hughes, DDS Debby Hwang, DMD Mian Iqbal, DMD, MS Tassos Irinakis, DDS, MSc James Jacobs, DMD Ziad N. Jalbout, DDS John Johnson, DDS, MS Sascha Jovanovic, DDS, MS John Kois, DMD, MSD Jack T Krauser, DMD Gregori Kurtzman, DDS Burton Langer, DMD Aldo Leopardi, DDS, MS Edward Lowe, DMD Shannon Mackey Miles Madison, DDS Carlo Maiorana, MD, DDS Jay Malmquist, DMD Louis Mandel, DDS Michael Martin, DDS, PhD Ziv Mazor, DMD Dale Miles, DDS, MS Robert Miller, DDS John Minichetti, DMD Uwe Mohr, MDT Jaimee Morgan, DDS Dwight Moss, DMD, MS Peter K. Moy, DMD Mel Mupparapu, DMD Ross Nash, DDS Gregory Naylor, DDS Marcel Noujeim, DDS, MS Sammy Noumbissi, DDS, MS Arthur Novaes, DDS, MS Andrew M. Orchin, DDS Charles Orth, DDS Jacinthe Paquette, DDS Adriano Piattelli, MD, DDS Stan Presley, DDS

George Priest, DMD Giulio Rasperini, DDS Michele Ravenel, DMD, MS Terry Rees, DDS Laurence Rifkin, DDS Georgios E. Romanos, DDS, PhD Paul Rosen, DMD, MS Joel Rosenlicht, DMD Larry Rosenthal, DDS Steven Roser, DMD, MD Salvatore Ruggiero, DMD, MD Anthony Sclar, DMD Frank Setzer, DDS Maurizio Silvestri, DDS, MD Dennis Smiler, DDS, MScD Dong-Seok Sohn, DDS, PhD Muna Soltan, DDS Michael Sonick, DMD Ahmad Soolari, DMD Christian Stappert, DDS, PhD Neil L. Starr, DDS Eric Stoopler, DMD Scott Synnott, DMD Haim Tal, DMD, PhD Gregory Tarantola, DDS Dennis Tarnow, DDS Geza Terezhalmy, DDS, MA Tiziano Testori, MD, DDS Michael Tischler, DDS Michael Toffler, DDS Tolga Tozum, DDS, PhD Leonardo Trombelli, DDS, PhD Ilser Turkyilmaz, DDS, PhD Dean Vafiadis, DDS Hom-Lay Wang, DDS, PhD Benjamin O. Watkins, III, DDS Alan Winter, DDS Glenn Wolfinger, DDS Richard K. Yoon, DDS

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Editorial Commentary

I

We Have the Technology. Let’s Use It!

am a big history buff and I am always amazed at the progress of mankind. When you think about what we as a people have accomplished, it literally boggles the mind. As civilizations developed in millennia past, the isolation of different communities resulted in a great number of technologies that were quite disparate from one another. The sheer distances between these communities and the difficulties of travel imposed by various natural and human elements hampered the sharing and dissemination of these technologies. In ancient times, the main source of communication between civilizations rested in the hands of merchant traders. As they traveled to distant lands to exchange goods, these traders also acquired knowledge; knowledge of different cultures and customs, knowledge of different arts and humanities, and most importantly, knowledge of different technologies. Upon their return home, this knowledge was imparted to their native peoples and incorporated or adapted to fit their needs. This process was difficult, often dangerous, and could take many years to complete. Now let’s shift gears and think about how all of this relates to our beloved profession of dentistry. As recently as just a few years ago, the dissemination of knowledge in our community was a painfully slow process. Essentially, if a new technique or product was to be discussed, it was first published in a print journal. As I have mentioned in a previous editorial, the peer review and publication process for such an article can take up to 24 months. While waiting for the articles to be published, companies wishing to promote their new product, or procedures using their products, would do a few things to get out information faster. First, they would advertise. Second, they would hold company sponsored training sessions and

continuing education seminars. Third, they would sponsor presentations at large organizational meetings. The company sponsored campaigns did an effective job of generating interest in the new technique or product, but it was not until the articles were actually published that they gained full acceptance. Once the articles were published, hopefully, you subscribed to the journal publishing said articles. If not, you could purchase the article for upwards of $30 or you were just simply out of luck. When the Journal of Implant and Advanced Clinical Dentistry (JIACD) was released in early 2009, this process changed for the better. Firstly, JIACD is available to everyone at no charge. Second, JIACD is freely accessible via the internet. With the simple click of a button, the entire world has access to every article ever published in JIACD. Third, because JIACD is an online publication with an enormous peer review board, articles may be reviewed and published with extraordinary promptness. I suspect that it is only a matter of time before other journals begin to follow our lead. The time has come for dental information to be free and instantly accessible to all. Modern technology has made the world a much smaller place, mainly through vast improvements in our ability to communicate with one another. Compared to our ancestors, when you think about how easy it is for us to acquire knowledge in modern times, it is almost embarrassing. ●

Dan Holtzclaw, DDS, MS Founder, Co-Editor-In-Chief

Nick Toscano, DDS, MS Founder, Co-Editor-In-Chief

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Kurtzman


Case of the Month Biologic Shaping

Kurtzman

Daniel Melker, DDS1 Abstract

W

hen performing conventional crown lengthening, the existing margins of an old restoration or the cementoenamel junction (CEJ) of a non-restored tooth are used to determine necessary bone removal to establish adequate space for biologic width. Creating proper space for biologic width ensures that the new margin will not infringe upon the periodontal complex and reduces the likelihood for future inflammation. One significant problem of this procedure is that, at times, significant bone must be removed. This can weaken the stability of the tooth or create a weakened and vulnerable furcation area. The more bone removed in the furcation, the greater the likelihood of future problems with maintenance. It is critical to preserve as much bone as possible to support the tooth, especially in the furcation area.

Considering these and other important aspects of crown lengthening, the concept of “Biologic Shaping” was established. Reasons for Biologic Shaping include: 1) Replace or supplement the current indications for clinical crown lengthening; 2) Minimize ostectomy; 3) Facilitate supragingival or intrasulcular margins to preserve biologic width; 4) Eliminate developmental grooves; 5) Eliminate previous subgingival restorative margins; 6) Reduce or eliminate furcation anatomy and thus facilitate margin placement; 7) Allow supragingival or intracrevicular impression techniques. The following article presents a series of Biologic Shaping cases and the author discusses requirements for successful treatment gleaned over the past 33 years of his career in which he has used this technique on over 30,000 teeth.

KEY WORDS: Biologic shaping, biologic width, ostectomy, osteoplasty 1. Private practice limited to periodontics, Clearwater, Florida, USA

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Melker

The clinical prerequisites and steps for success with Biologic Shaping are as follows: 1. All previous restorative materials and decay should be removed. 2. A core buildup of composite bonded resin should be placed where necessary to add volume to the teeth. The core helps determine where the final margin placement of the new restoration will be placed.

8. Once the flaps are adapted, Potassium oxylate should be used to help decrease post-surgical sensitivity. The liquid is applied to the root surface for 45-60 seconds and then lightly air dried. Repeat 2-3 times. 9. Cement provisional prosthesis with a Polycarboxlate cement such as Tylok® (Dentsply International; York, Pennsylvania, USA) or Durelon.

3. Acrylic provisionals should be placed with Durelon (3M™ ESPE™; St. Paul, Minnesota, USA) as the temporary cement. This cement is recommended for its antimicrobial properties and ability to help decrease sensitivity.

10. Homecare instructions include rinsing with Chlorhexidine twice daily (morning and evening) and brushing with Prevident at bedtime. After meals the patient rinses with water or Listerine to remove any food particles.

4. Removal of provisional restorations at time of surgery to allow better access.

11. At 4 weeks, the provisionals are either remade or relined leaving 1mm of space for continued Biologic Width growth in a coronal direction. No margination of tooth surface at this time.

5. Shape root and remove old margin as well as 360 degrees of CEJ’s. Reduce or eliminate cervical enamel projections. Facilitate ideal restorative emergence profile (Flat is better than fat contours). Diamond burs are recommended for this process. 6. Correct any reverse architecture and remove necessary bone where violation of biologic width may still be anticipated. 7. If insufficient keratinized tissue is present at the surgical site, add sufficient connective to protect bone from bacterial infiltration. The connective also protects underlying periodontal tissues from impression material and cementation irritation.

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12. At 14 weeks Chamfer margins are placed at the gingival collar and impressions taken. When endodontics is present the new margin may be placed within the sulcus. 13. Facilitate hygiene and maintenance procedures. Correspondence Dr. Daniel Melker 28465 US HWY 19 N Suite 204 Clearwater, FL 33761 Phone: (727) 725-0100 Email: djmelker@yahoo.com


Melker

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Melker

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November 2009


Melker

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JIACD Continuing Education JIACD Continuing Education Management of the Actively Bleeding and Hypovolemic Dental Patient

Dan Holtzclaw, DDS, MS • Nicholas Toscano, DDS, MS Abstract

Background: With an increasing number of dentists incorporating surgical procedures such as implant dentistry into their daily practice, the ability to manage hemorrhagic complications is indispensable. The purpose of this article is to provide an updated review on contemporary oral hemostatic measures and offer literature based recommendations on the perioperative management of the actively bleeding and hypovolemic dental patient. Methods: The authors reviewed medical and dental literature for reports of dental related hemorrhagic complications, oral hemostatic measures, and treatment of hypovolemia.

Results: Dental literature reported life threatening hemorrhagic complications with common surgical dental procedures ranging from endosseous implant placement to third molar extractions. In most cases, actively bleeding and hypovolemic patients were managed with relatively simple local measures. Conclusions: Under most circumstances, and with proper management, the risk of uncontrolled hemorrhage attributed to dental procedures is minimal. Proper management in such scenarios involves adequate pre-operative patient assessment, proficiency with local hemostatic control measures, and familiarity with hypovolemic treatment protocols.

KEY WORDS: Hypovolemia, bleeding, hemostasis, emergency 1. Private practice limited to Periodontics and Implant Dentistry, Austin, TX, USA 2. Private practice limited to Periodontics and Implant Dentistry, Washington DC, USA This article provides 2 hours of continuing education credit. Please click here for details and additional information.

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JIACD Continuing Education

Learning Objectives After reading this article, the reader should be able to: 1. Recognize the signs and symptoms of hypovolemia. 2. Understand how to manage hypovolemia. 3. Understand how to manage intraoral hemorrhaging.

INTRODUCTION Though rare, life threatening hemorrhage has been reported with common surgical dental procedures ranging from endosseous implant placement to third molar extractions.1-3 With an increasing number of dentists now incorporating surgical procedures into their daily practice, their risk of encountering hemorrhagic complications is likely to increase.4-8 Knowledge of predisposing factors, physiologic responses to, and clinical management of excessive hemorrhage may prove useful for providers in such situations. Accordingly, the purpose of this case report is to review hemorrhage management in the dental setting and to provide an example of practical application of such principles.

PRE-OPERATIVE CONSIDERATIONS With systemically healthy patients, the possibility of uncontrolled hemorrhage resulting from a dental procedure seems remote. In fact, the risk of moderate to severe bleeding induced by dental treatment is less than 1% for the average patient.9 While obvious conditions such as Hemophilia and Von Willenbrand’s Disease may cause clinicians to consider the possibility of hemorrhagic com-

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plications, most providers commonly associate potential bleeding problems with patients taking antiplatelet and/or anticoagulation medications. Improved understanding of cardiovascular physiology and advances in the management and treatment of cardiovascular disease have rendered oral anticoagulation therapy a mainstay of modern medicine. It is estimated that more than 50 million Americans adhere to a low dose daily aspirin protocol and other anticoagulants such as warfarin sodium and clopidogrel bisulfate routinely rank among the top 50 medications prescribed in the United States.10,11 As such, the likelihood of encountering anticoagulated patients is significant. Should clinicians be worried about uncontrolled hemorrhage with these patients? Studies examining the hemorrhagic effects of antiplatelet anticoagulants on dental procedures have found negligible increases in intraoperative and postoperative bleeding when local measures were used.1214 Likewise, similar studies evaluating coagulation cascade anticoagulants have generally found no increased risk of intraoperative or postoperative bleeding that could not be controlled with local measures when International Normal Ratio (INR) values were within therapeutic levels.15-18 In addition to pre-operative consideration of a patient’s medication profile, anticipated blood loss from the planned procedure must be considered. Expectant blood loss from a restorative procedure such as a dental amalgam will be considerably different from that of a surgical procedure such as dental implant placement, periodontal flap procedure, or impacted third molar extraction. Studies evaluating blood loss from restorative procedures have reported minimal hemorrhagic complications, while those evaluating surgical operations such as flap-osseous procedures have found up to 592ml


JIACD Continuing Education

of blood loss from a single surgical site.19,20 Blood loss from surgical procedures is also influenced by the experience level of the provider. Surgeries performed by less experienced providers have been shown to take up to three times longer and may result in nearly twice as much blood loss as those performed by more experienced practitioners.20 In general, however, most studies have found that blood loss from dental procedures is under 200ml and may be even less if the duration of the procedure does not exceed 2 hours.20-23 Considering that a pint of blood, the amount generally taken during blood donation, is 473ml, the amount of blood lost during most dental procedures is well within the limits of safety.

HYPOVOLEMIA RECOGNITION AND MANAGEMENT Life threatening situations resulting from excessive blood loss are often due to hypovolemic induced hemorrhagic shock.24 Blood loss exceeding 1000ml, or 1/5 of an adult’s average blood volume, may precipitate hypovolemic shock and lead to inadequate tissue perfusion/oxygenation.25 Compensatory signs of hypovolemia include tachycardia, hypotension, tachypnea, pallor, diaphoresis, anxiety, nausea, thirst, and light headedness. If left untreated, hemorrhagic shock may progress to loss of consciousness, coma, or even death. When the source of bleeding is known, primary goals in the treatment of hemorrhagic shock are to stop the source of hemorrhaging and restore circulating blood volume. The “three-toone” rule for the treatment of hemorrhagic shock dictates the administration of 3ml of crystalloid (Lactated Ringers solution or normal saline) for every 1ml of blood loss replaced.26 Although hemorrhagic shock does not typically occur until

Figure 1: Blood clot removed from patient with slow continuous hemorrhaging secondary to osseous periodontal surgery.

blood loss exceeds 1000ml, dental literature recommends fluid replacement when blood loss exceeds 500ml to account for postoperative hemorrhagic oozing (figure 1).27,28 A pragmatic approach to fluid resuscitation in outpatient dental settings is limited to cases with less than 1000ml of blood loss and the ability to control hemorrhaging. Cases exceeding these parameters should be referred to a higher echelon of care.

HEMHORRAGE MANAGEMENT With proper management, nearly all scenarios of excessive bleeding can be adequately managed with relatively simple local measures (Figure 2, Table 1) such as: Positive Pressure Positive pressure aids hemostasis by promoting occlusion of the site of injury and providing mechanical aid to clot formation.29 Positive pressure to intraoral wounds is typically accomplished by compressing moistened gauze on the site of hemorrhaging. Suturing wound margins or severed vessels is another method in which compressive force may be applied to bleed-

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JIACD Continuing Education

Table 1: Local Hemostatic aids Product or Action

Composition

Action

Positive Pressure

N/A

Manual occulusive aid to clot formation

Vasoconstrictor

1:100,000 Epinephrine

Activation of a adrenergic receptors

Gelfoam®

Porcine derived gelatin sponge

Occlusive matrix; activation of intrinsic pathway

Surgicel®

Plant derived a-cellulose

Occlusive matrix: activation of intrinsic pathway, antibacterial properties

CollaCote®, CollaPlug® CollaTape®, UltraFoamTM UltraWrapTM

Bovine derived collagen

Occlusive matrix, activation of intrinsic pathway

Crustacean derived chitosan

Positively charged chitosan attracts negatively negatively charged red blood cells, antibacterial properties

Tranexamic acid

Binds to lysine receptor sites on plasmin and plasminogen inhibiting fibrin binding and fibrinolysis

Bovine derived thrombin

Enhances conversion of fibrinogen to fibrin

N/A

High frequency electric current cauterizes tissue and induces blood coagulation

HemCon®

4.8% Tranexamic Acid Mouth Rinse

Topical Thrombin Electrocautery

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JIACD Continuing Education

whole blood.32 Absorbable collagen sponges aids hemostasis by providing a simple occlusive matrix and through contact activation of the intrinsic pathway.33 When used for oral applications, this material typically liquefies within 2-5 days.

Figure 2: Products commonly used to aid hemostasis. Clockwise from top: Gelatin sponge, Collagen plug, Collagen tape, Oxidized regenerated cellulose, Chitosan derived.

ing areas.30 In many cases, minor hemorrhaging is often controlled with positive pressure alone. Vasoconstrictor Dental anesthetics contain vasoconstrictor primarily to increase their duration of action and minimize the risk of local anesthetic toxicity.31 Epinephrine, the most commonly utilized vasoconstrictor in dental local anesthetics, is a catecholamine that facilitates vasoconstriction via the activation of alpha adrenergic receptors. Alpha adrenergic activation by sympathomimietic drugs such as epinephrine induces smooth muscle contraction within blood vessels and ultimately leads to short term vasoconstriction. Absorbable Gelatin Sponge Gelfoam® (Pfizer, New York, NY) is a resorbable gelatin sponge of porcine origin that is capable of absorbing up to 45 times it weight in

Oxidized Regenerated Cellulose Oxidized regenerated cellulose based products such as Surgicel® (Ethicon Inc, Somerville, NJ) are derived from plant based alpha-cellulose and function hemostatically in a manner similar to absorbable gelatin sponges.34 A unique property of oxidized regenerated cellulose is antibacterial activity. Because this product has a relatively low pH, a broad range of gram negative, gram positive, and antibiotic-resistant bacteria have proven to be locally susceptible to oxidized regenerated cellulose.35 When used for oral applications, this product typically resorbs with 7-14 days. Absorbable Collagen Products Absorbable collagen products such as collagen tape, collagen plugs, and collagen foam are derived from bovine deep flexor tendons and typically resorb completely within 14 days.36 Additional bovine derived products such as Avitene®, UltraFoam™, and UltraWrap™ (Traatek, Inc, Fort Lauderdale, FL.) have similar properties. In addition to providing a simple occlusive matrix, these products promote hemostasis by virtue of their collagen content which activates the intrinsic coagulation cascade. Chitosan Derived Products Chitosan derived products such as HemCon® (HemCon Medical Technologies Inc, Portland, OR.) are extremely effective at promoting hemostasis and have recently been used by United

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JIACD Continuing Education

States military medical personnel for treatment of battlefield injuries. Chitosan is a naturally occurring polysaccharide that is commercially produced via the deacetylation of crustacean chitin.37 Positively charged chitosan molecules readily attract negatively charged red blood cells and the two form an extremely strong seal that acts as a primary occlusive barrier for hemorrhagic sites. With hemorrhaging limited and/ or stopped by this initial seal, the natural coagulation cascade ensues. Like oxidized regenerated cellulose, chitosan derived products have locally active antibacterial properties.38 Unlike oxidized regenerated cellulose which relies on low pH for its antibacterial activity, however, chitosan derived products achieve antibacterial properties via active cell wall disruption.39 Tranexamic Acid Tranexamic acid is an anticoagulant oral rinse that binds to lysine receptor sites on plasmin and plasminogen, ultimately inhibiting fibrin binding and fibrinolysis.40 This rinse is supplied in a 4.8% solution and patients may be instructed to rinse with 10ml four times daily for 7 days following surgery.41 Rinsing with tranexamic acid solution results in therapeutic levels ( >100mg/ml) within the saliva for 2-3 hours. Wounds healing in the presence of tranexamic acid have demonstrated increased tensile strength, thus making the clot more resistant to mechanical disruption.42 Topical Thrombin Topical thrombin facilitates clot stabilization by enhancing the conversion of fibrinogen to fibrin and forming a reinforcing meshwork for initial platelet plugs. Medical grade topical throm-

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bin is often bovine derived and is typically supplied as a freeze dried sterile powder that must be reconstituted with sterile saline. For general use in dental applications, a topical thrombin solution of 100 International Units/ml is recommended.43 Topical thrombin is often delivered via pump/syringe spray or combined with a carrier such as a hemostatic gelatin sponge. Electrocautery Electrocautery involves the application of a highfrequency electric current to cauterize tissue and induce blood coagulation. In dentistry, this process is typically accomplished with monophasic electrosurgical units. In comparison to other local means of hemostasis management, electrocautery may induce collateral thermal damage to adjacent tissues.44,45 As such, this treatment option is typically reserved for severe hemorrhaging scenarios.

PRACTICAL CASE REPORT The primary author was contacted by a patient with a chief complaint of “my mouth won’t stop bleeding.” Telephonic interview revealed the patient to be a 22 year old white male with a noncontributory medical history. The patient had undergone impacted third molar extractions one week prior and was without complication until the bleeding episode. According to the patient, his lower right extraction site began to hemorrhage during dinner subsequent to traumatic disruption with a piece of partially masticated food. The patient had attempted to control the bleeding by biting on moistened paper towels for over 2 hours prior to contacting the clinic. Upon arrival of the treatment provider to the dental clinic, the patient appeared ashen, diaphoretic, and continued to actively bleed from


JIACD Continuing Education

the mouth. The patient was seated in a dental chair and rapid evaluation revealed fast paced active hemorrhaging from extraction site 32 and vital signs of the following: blood pressure (90/48), pulse (99), and oxygen saturation (95%). Using the pace of the active hemorrhaging as a guide, it was estimated that the patient had lost approximately 1000ml of blood at this point. As vital signs were being taken, the patient began to complain of “dizziness” and nausea. The patient was placed into Trendelenburg position, oxygen was administered via nasal canula at a rate of 6L/min, oral suction was initiated, and intravenous access was obtained in the left antecubital vein with an 18 gauge catheter. As 2000ml of Lactated Ringers solution were delivered to the patient, attempts were made to stop the hemorrhaging. The patient was repositioned and site 32 was generously infiltrated with 2% lidocaine/1:100,000 epinephrine. As the vasoconstrictor took effect, bleeding from site 32 decreased significantly and the patient was instructed to bite with positive pressure on moist gauze as he received the remainder of the Lactated Ringers solution. After 30 minutes of subsequent evaluation, hemorrhaging from extraction site 32 ceased and the patient’s vital signs stabilized to within normal limits.

CONCLUSION Dental literature clearly demonstrates that under most circumstances, and with proper management, the risk of uncontrolled hemorrhage attributed to dental procedures is minimal. Proper management in these scenarios involves adequate pre-operative patient assessment, proficiency with local hemostatic control measures, and familiarity with hypovolemic

treatment protocols. As more general dentists now routinely perform surgical procedures that induce blood loss, such a knowledge base is essential and may one day prove life saving. ● Professional Dental Education and Professional Education Services Group are joint sponsors with The Academy of Dental Learning in providing this continuing dental education activity. The Academy of Dental Learning is an ADA CERP Recognized Provider. The Academy of Dental Learning designates this activity for two hours of continuing education credits. ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor does it imply acceptance of credit hours by boards of dentistry Correspondence: Dr. Dan Holtzclaw 3016 Hidden Bluff Cove Round Rock, TX 78665

For 2 hours CE CrEdit takE thE Quiz on thE nExt pagE

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JIACD Continuing Education

Disclosure The authors report no conflicts of interest with anything mentioned in this article. References 1. Mason M, Triplett R, Alfonso W. Life-threatening hemorrhage from placement of a dental implant. J Oral Maxillofac Surg 1990; 48(2): 201-4.

15. Ward B, Smith M. Dentoalveolar procedures for the anticoagulated patient: literature recommendations versus current practice. J Oral Maxillofac Surg 2007; 65(8): 1454-60. 16. Alexander R, Ferretti A, Sorensen JR. Stop the nonsense not the anticoagulants: a matter of life and death. NY State Dent J 2002; 68(9): 24-6.

2. Moghadam H, Caminiti M. Life-threatening hemorrhage after extraction of third molars: case report and management protocol. J Can Dent Assoc 2002; 68(11): 670-4.

17. Cannon P, Dharmar V. Minor oral surgical procedures in patients on oral anticoagulants-a controlled study. Aust Dent J 2003; 48(2): 115-8.

3. Kalpidis C, Konstantinidis A. Critical hemorrhage in the floor of the mouth during implant placement in the first mandibular premolar position: A case report. Implant Dent 2005; 14(2): 117-24.

18. Evans I, Sayers M, Gibbons A, Price G, Snooks H, Sugar A. Can warfarin be continued during dental extraction? Results of a randomized controlled trial. Br J Oral Maxillofac Surg 2002; 40(3): 248-52.

4. Misch C. Implants and the general practitioner. Dent Today 2007; 26(8): 48-52.

19. Rooney T. General dentistry during continuous anticoagulation therapy. Oral Surg Oral Med Oral Pathol 1983; 56(3): 252-5.

5. Bitter R. The periodontal factor in esthetic smile design: Altering gingival display. Gen Dent 2007; 55(7): 616-22. 6. Cottrell D, Reebye U, Blyer S, Hunter M, Mehta N. Referral patterns of general dental practitioners for oral surgical procedures. J Oral Maxillofac Surg 2007; 65(4): 686-90.

20. Baab D, Ammons W, Selipsky H. Blood loss during periodontal flap surgery. J Periodontol 1977; 48(11): 693-8. 21. McIvor J, Wengraf A. Blood-loss in periodontal surgery. Dent Pract Dent Rec 1966; 16(12): 448-51.

31. Malamed S. Handbook of Local Anesthesia 5th Edition. Mosby 2004: 416. 32. Council on Pharmacy and Chemistry: Absorbable gelatin sponge – new and nonofficial remedies. JAMA 1947; 135: 921. 33. Ongkasuwan J. Hemostatic agents. Baylor College of Medicine Grand Rounds Archive 2005; 10: 1-9. 34. Surgicel, Surgicel Nu-Knit, and Surgicel Fibrillar Absorbable Hemostat (oxidized regenerated cellulose) for Dental Use package insert. Somerville, NJ: Ethicon, Inc 2003; 1-14. 35. Spangler D, Rothenburger S, Nguyen K, Jampani H, Weiss S, Bhende S. In vitro antimicrobial activity of oxidized regenerated cellulose against antibiotic-resistant microorganisms. Surg Infect 2003; 4(3): 25562. 36. Collagen Dental Wound Dressings package insert. Brockton, MA: Collagen Matrix, Inc: 1-2. 37. HemCon Dental Dressing package insert. Portland, OR: HemCon Medical Technologies Inc: 1-30 38. Muzzarelli R, Tarsi R, Filippini O, Giovanetti E, Biagini G, Varaldo P. Antimicrobial properties of N-carboxybutyl chitosan. Antimicrob Agents Chemother. 1990; 34(10): 2019-23.

7. Lanning S, Best A, Hunt R. Periodontal services rendered by general practitioners. J Periodontol 2007; 78(5): 823-32.

22. Hecht A, App A. Blood volume lost during gingivectomy using two different anesthetic techniques. J Periodontol 1974; 45(1): 9-12.

8. Starr C, Maksoud M. Implant treatment in an urban general dentistry residency program: A 7 year retrospective study. J Oral Implantol 2006; 32(3): 142-7.

23. Berdon J. Blood loss during gingival surgery. J Periodontol 1965; 36: 102-7.

39. Andres Y, Giraud L, Gerente C, Le Cloirec P. Antibacterial effects of chitosan powder: mechanisms of action. Environ Technol 2007; 28(12): 1357-63.

24. Perry M, O’Hare J, Porter G. Advanced trauma life support (ATLS) and facial trauma: Can one size fit all? Part 3: Hypovolaemia and facial injuries in the multiply injured patient. Int J Oral Maxillofac Surg 2008; 37(5): 405-14.

40. Gaspar R, Brenner B, Ardekian L, Peled M, Laufer D. Use of tranexamic acid mouthwash to prevent postoperative bleeding in oral surgery patients on oral anticoagulant medication. Quintessence Int 1997; 28(6): 375-9.

25. Gutierrez G, Reines H, Wulf-Gutierrez M. Clinical review: hemorrhagic shock. Crit Care 2004; 8(5): 373-81.

41. Bandrowsky T, Vorono A, Borris T, Marcantoni H. Amoxicillin-related postextraction bleeding in an anticoagulated patient with tranexamic acid rinses. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996; 82(6): 610-2.

9. Curtis J, McLain J, Hutchinson R. The incidence and severity of complications and pain following periodontal surgery. J Periodontol 1985; 56(10): 597-601. 10. Ajani U, Ford E, Greenland K, Giles W, Mokdad A. Aspirin use among U.S. adults: Behavioral Risk Factor Surveillance System. Am J Prev Med 2006; 30(1):74-7. 11. Top 50 Drugs Prescribed 2007. Humana Inc. Publication 2007: 1-2.

26. Healey M, Davis R, Liu F, Loomis W, Hoyt D. Lactated ringer’s is superior to normal saline in a model of massive hemorrhage and resuscitation. J Trauma 1998; 45(5): 894-9.

12. Ardekian L, Gaspar R, Peled M, Brener B, Laufer D. Does low-dose aspirin therapy complicate oral surgical procedures? J Am Dent Assoc 2000; 131(3): 331-5.

27. Gores R, Royer R, Mann F. Blood loss during operation for multiple extraction with alveoloplasty and other oral surgical procedures. J Oral Surg 1955; 13(4): 299-306.

13. Madan G, Madan S, Madan G, Madan A. Minor oral surgery without stopping daily low-dose aspirin therapy: a study of 51 patients. J Oral Maxillofac Surg 2005; 63(9): 1262-5.

28. Johnson R. Blood loss in oral surgery. J Dent Res 1956; 35(2): 175-84.

14. Partridge C, Campbell J, Alvarado F. The effect of platelet-altering medications on bleeding from minor oral surgery procedures. J Oral Maxillofac Surg 2008; 66(1): 93-7.

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29. Meehan S, Schmidt M, Mitchell P. The international normalized ratio as a measure of anticoagulation: Significance for the management of the dental outpatient. Spec Care Dentist 1997; 17(3): 94-6. 30. Purcell C. Dental management of the anticoagulated patient. N Z Dent J 1997; 93(413): 87-92.

42. Björlin G, Nilsson I. The effect of antifibrinolytic agents on wound healing. Int J Oral Maxillofac Surg 1988; 17(4): 275-6. 43. Thrombin, Topical U.S.P. (Bovine Origin) package insert. Middleton, WI: GenTrac Inc 2007: 1-2. 44. Noble W, McClatchey K, Douglass G. A histologic comparison of effects of electrosurgical resection using different electrodes. J Prosthet Dent 1976; 35(5): 575-9. 45. Arashiro D, Rapley J, Cobb C, Killoy W. Histologic evaluation of porcine skin incisions produced by CO2 laser, electrosurgery, and scalpel. Int J Periodontics Restorative Dent 1996; 16(5): 479-91.


JIACD Continuing Education

Continuing Education JIACD Quiz #4 1. The risk of moderate to severe bleeding induced by dental treatment is less than: a. 1% c. 5% b. 2% d. 10% 2. An estimate of how many Americans adhere to a low dose daily aspirin protocol? a. 2 million c. 50 million b. 14 million d. 75 million 3. Surgical operations such as flaposseous procedures have found up to how much blood loss from a single surgical site? a. 100 ml c. 495 ml b. 250 ml d. 592 ml 4. Surgeries performed by less experienced providers have been shown to take up to how many times longer than those performed by more experienced practitioners? a. 2 times longer c. 4 times longer b. 3 times longer d. 5 times longer 5. In general, most studies have found that blood loss from dental procedures is: a. Negligible c. < 200 ml b. < 100 ml d. > 500 ml

6. How much blood loss may precipitate hypovolemic shock and lead to inadequate tissue perfusion/ oxygenation? a. 100 ml c. 750 ml b. 250 ml d. 1,000+ ml 7. Compensatory signs of hypovolemia include which of the following? a. Tachycardia d. Nausea b. Hypotension e. All of the above c. Tachypnea 8. How many milliliters of crystalloid should be administered for every 1 milliliter of blood lost? a. 1 ml c. 3 ml b. 2 ml d. 5 ml 9. Methods of hemorrhage management include which of the following? a. Positive pressure d. Electrocautery b. Vasoconstrictor e. All of the above c. Absorbable gelatin sponge 10. Rinsing with tranexamic acid solution results in therapeutic levels (>100mg/ ml) within the saliva for how long? a. 30 – 45 minutes c. 3 – 4 hours b. 2 – 3 hours d. 5 – 6 hours

CliCk hErE to takE thE Quiz The Journal of Implant & Advanced Clinical Dentistry

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Single Surgery Comprehensive Gingival Grafting Utilizing Palatal Donor Tissue

Wilcko et al

M. Thomas Wilcko, DMD1 • William M. Wilcko, DMD, MS2 Abstract

Background: As many as 24 teeth can be grafted in a single surgical appointment utilizing the patient’s own palatal tissue. If more than a dozen teeth require grafting, thick free gingival grafts (FGG’s) can be split and the resulting subepithelial connective tissue grafts (SCTG’s) can be utilized in a bilaminar approach. The resultant thinner FGG’s can be used in conjunction with a retained semilunar flap and marginal tissue lifting. This case series presents 4 cases in which SCTG’s or a combination of SCTG’s and FGG’s are utilized for multiple areas of gingival grafting at the same surgical appointment. Methods:

Four cases are presented in

which multiple areas of gingival recession are treated in a single surgical appointment utilizing autogenous palatal donor tissue. Historical background and clinical descriptions of the surgical techniques are presented. Results: In all four cases, multiple areas of gingival grafting were accomplished in a single surgery resulting in root coverage and a structurally enhanced zone of gingival attachment. Conclusion: With the techniques described in this paper, the palate can provide an adequate amount of donor tissue for single surgery comprehensive gingival grafting of up to 24 sites.

KEY WORDS: Subepithelial connective tissue graft, free gingival graft 1. Private practice limited to Periodontics, Erie, Pennsylvania, USA, Clinical Associate Professor of Periodontology, Case University, Cleveland OH, Consultant, Naval Dental Center, Bethesda, MD 2. Private practice limited to Orthodontics, Erie, Pennsylvania, USA, Consultant, Naval Dental Center, Bethesda, MD

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INTRODUCTION Over the past 45 years, gingival grafting utilizing palatal donor tissue has evolved from merely a functional application for increasing the width and thickness of the gingival attachment to also addressing esthetics by providing for reconstructive root coverage. The use of the subepithelial connective tissue graft (SCTG) is now widely accepted as the gold standard of care in root coverage grafting.1 Historical Perspective The use of the free gingival graft (FGG) was first reported by Björn in 1963 for repair of a functionally deficient zone of gingival attachment.2 This technique was later improved upon by Miller to also provide for root coverage in Class I and Class II marginal tissue recession.3 The preparation of the recipient site was accomplished through the sharp dissection of a split thickness flap leaving a very thin exposed vascular surface overlying the bone onto which the FGG was sutured. The FGG itself included both the epithelium and underlying connective tissue and, consequently, the resulting donor site in the palate was subject to relatively slow healing through secondary intention. The use of an acrylic palatal stent to cover the donor site during healing lessened the likelihood of any significant postoperative bleeding and discomfort. As the predictability of root coverage became more of a priority, newer bilaminar techniques evolved in which palatal connective tissue was sandwiched between the denuded root surfaces and overlying partial or full thickness flaps.4-9 Another bilaminar technique using SCTG’s has also been reported with tunnel procedures.10-15 The epithelial covering of the free gingival

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graft was no longer needed in these bilaminar approaches and, as such, the harvesting technique from the palatal donor site evolved into the excision of connective tissue only, reducing the palatal donor site to an internal pouch. This permitted almost complete surface closure and healing of the palatal donor site by primary intention. The disadvantage of this technique is that only a rather limited amount of connective tissue can be retrieved during harvesting.

MATERIALS AND METHODS Single Surgery Comprehensive Grafting When a pouch technique is utilized for graft harvesting, adequate SCTG can usually be harvested from one side of the palate to graft about 3 teeth on average, for a total of approximately half a dozen teeth if both sides of the palate are used. When SCTG is required for root coverage on more than 6 teeth and one wishes to accomplish the grafting in a single surgical appointment, it is necessary to abandon the internal pouch technique of graft harvesting and instead harvest multiple FGG’s from the palate. If FGG’s are harvested from the palate and deepithelialized, enough subepithelial connective tissue can be obtained to perform root coverage grafting on about a dozen teeth at a single surgical appointment. If more than a dozen teeth require root coverage grafting and one wishes to utilize strictly subepithelial connective tissue, grafting can be performed in two separate surgeries leaving enough time between the surgeries for the palate to regenerate. The manner in which single surgery comprehensive gingival grafting can be accomplished when more than a dozen teeth require gingival grafting is to place the emphasis for root cov-


Wilcko et al

Figure 1a: Thick free gingival graft.

erage on the areas of gingival recession in the upper arch where esthetics is typically more of an issue and to place an emphasis on improving the functional and structural integrity of the zone of gingival attachment on the areas of gingival recession in the lower arch by striving to increase the width, thickness, and continuity of the gingival attachment. An attempt is also made to achieve some degree of root coverage in the lower arch, but this is presented to the patient with lower expectations. In this manner, up to two dozen teeth can usually be grafted in a single surgical appointment utilizing the patient’s own palatal tissue. This is made possible by removing thick FGG’s from the palate and then precisely splitting them (figures 1a,1b). Each thick FGG that is harvested from the palate is thus transformed into a thinner FGG and a separate SCTG (figure 1c). By doing so, the amount of palatal tissue made available for grafting is quickly doubled with the SCTG’s utilized in a bilaminar approach in the upper arch and the FGG’s utilized in the lower arch. Because thick FGG’s are needed, the greater

Figure 1b: Carefully splitting thick free gingival graft from figure 1a.

Figure 1c: Results from splitting graft: (1) thinner free gingival graft and (1) subepithelial connective tissue graft.

palatine artery can be inadvertently cut during the graft harvesting. This is addressed by using interrupted loop sutures over the area to compress the tissues and slow the bleeding. The donor sites are then covered with an acrylic stent to apply slight pressure, improve comfort, and reduce the likelihood of postsurgical bleeding. Recipient Site Preperation for SCTGs The recipient sites for SCTG’s are prepared prior to graft harvest. When a bilaminar

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onal flap advancement, and to assure passive adaptation at closure. Following reflection of the flap, intramarrow penetrations or cortical cuts are made interradicularly in the exposed bone.

Figure 2: Multiple free gingival grafts harvested from the palate.

approach is being used to maximize root coverage, full thickness flap reflection is utilized at the recipient sites. Partial thickness flap reflection can also be utilized at the recipient sites with equally good results, but this technique results in a thinner flap that can easily tear during reflection. Intrasulcular releasing incisions are utilized in the areas of gingival recession to include the facial aspects of the interdental papillae. Vertical releasing incisions are used at the opposite ends of the intrasulcular releasing incision and extended into the alveolar mucosa. In the posterior areas, the most distal vertical releasing incision is frequently omitted and, occasionally in isolated areas, no vertical releasing incisions are used. Regardless of whether or not vertical releasing incisions are included, a periosteal releasing incision is always made at the base of the flap for increased mobility, facilitation of cor-

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Recipient Site Preparation for FGG’s When FFG’s are used at recipient sites, preparation is done in a very different manner than that of SCTG’s. A semilunar incision is first made at the base of the remaining gingival attachment. If there is insufficient keratinized gingiva, the semilunar incision is made in the mucosal tissue. After the scalloped incision is made outlining the base of the semilunar flap, a split thickness flap is apically reflected through sharp dissection leaving the thinnest soft tissue layer possible as the vascular bed for the FGG’s. The reflection is carried 3 to 5 mm apical to the anticipated apical edge location of the FGG’s. The apical base of the semilunar flap semilunar flap is re-outlined with the tip of a #12 blade. This releases the collar over the root prominences and also slightly loosens 1 to 2 mm of the labial interdental papillae. The semilunar flap is then gently elevated coronally resulting in what is referred to as marginal tissue lifting. This is a delicate process requiring time and patience as care must be taken not to tear the semilunar flap. Considerations for Palatal FGG Harvesting and Preparation In the typical palate, 4 FGG’s (two from each side) can be harvested (figure 2). The size of the palate will of course determine the maximum width and length of the individual grafts. The bigger issue becomes the manner in which the grafts will be utilized. If 2 FGG’s are removed


Wilcko et al

Figure 3a: Superior edge of free gingival graft sutured.

Figure 3b: Periodontal dressing covering free gingival graft.

from the same side of the palate, 1 to 2 mm of palatal tissue is left between the donor sites to reduce healing time. It is also important to keep the border of the donor sites at least two millimeters shy of the posterior border of the stent to prevent exposing the donor site beyond the confines of the stent coverage. Generally, it is easier to remove a thicker FGG from the lateral aspect of the palate, where there is a thicker zone of subepithelial connective tissue to work with.

the superior edge of the FGG is very carefully sutured to the semilunar flap collars. Only the superior edge of the FGG is sutured (figure 3a). The FGG is held in close approximation to the underlying vascular bed with a periodontal dressing containing rosin that provides for improved adherence to the teeth (figure 3b).

Recipient Site Suturing of the FGGs The superior edge of the FGG is placed at the inferior border of the semilunar flap. For a starting point, one end of the FGG is sutured interproximally. The FGG is then stretched and the opposite end of the FGG is sutured at the most distant interproximal area. This results in the semilunar flap being elevated to cover some or all of the exposed root surfaces in the areas of the gingival recession. The FGG is then secured into position by suturing it at the remaining interproximal areas. Over the root prominences,

Recipient Site Suturing of the SCTGâ&#x20AC;&#x2122;s The coronal edge of the SCTG is first sutured interproximally (figure 4a) with a resorbable grafting material; 5-0 plain gut, 5-0 chromic gut, or 4-0 Vicryl (Ethicon) suture materials seem to work equally well. The superior edge of the SCTG must not come to a thin knifelike edge and may need to be trimmed to provide adequate thickness for suturing. The full thickness flap is coronally advanced to cover as much of the SCTG as possible (figure 4b). Complete coverage of the SCTG is preferable, but not always possible. The flap is sutured into position with a non-resorbable suture material such as CV-5 ePTFE, 3-0

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Figure 4a: Coronal edge of SCTG sutured.

Figure 4b: Coronally positioned flap covering SCTG.

PTFE, or 5-0 Polypropylene. Preferably, at least one sling suture should be used around each grafted tooth, and the SCTG should be re-engaged. No periodontal dressing is used.

The patient is asked to remain on a very soft diet until all of the sutures have been removed.

Post-operative Instructions and Follow up The patient is instructed to stay on a liquid or extremely soft food diet until told otherwise. The patient is given a very soft toothbrush and instructed to brush only the tips of the teeth. A palatal stent is delivered (figure 5) and the patient is instructed not to remove it. At one-week post surgery any periodontal dressing remaining is removed in addition to the sutures at the superior border of the FGG’s. The patient is still cautioned to remain on a very soft diet. The palatal stent is removed, cleaned, and reinserted after the palate is cleansed. With SCTG’s, the removal of the non-resorbable sutures is usually done in stages beginning two weeks post-operatively. Loose sutures are removed initially, but any tight functional sutures are left in place until three weeks postoperatively when the suture removal is completed.

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Patient Awareness and Expectations A well-informed patient with realistic expectations is critically important when treating gingival recession. To this end, it is emphasized to the patient that the most important aspect of any gingival grafting is to create an environment where additional gingival recession is less likely to occur. The most critical pre-treatment marker in determining the likelihood of achieving root coverage is the interproximal distance between the alveolar crest and the corresponding cemntoenamel junctions (CEJ) as seen on the periapical radiographs. Generally speaking, approximately 2.5mm is considered to be representative of an adequate biologic width,16-21 and this has proven to be an excellent measurement in predicting the likelihood of being able to achieve good root coverage. If radiographically the interproximal distance between the alveolar crest and the corresponding CEJ’s is 2.5mm or less, the like-


Wilcko et al

that is present. The resultant enhanced zone of gingival attachment created with this technique is conducive to coronal advancement at a second surgery if eventually deemed appropriate.22

Figure 5: Palatal stent covering palatal donor sites.

lihood of achieving fairly complete root coverage is high when a bilaminar approach with a SCTG and coronally advanced flap is utilized. As this interproximal distance increases beyond 2.5mm, there is a proportionate decrease in the amount of root coverage that can be expected. The most unappealing aspect of the FGG esthetics is the “tire patch” appearance at the localized recipient site. Extending the FGG’s to cover large numbers of teeth, even interspersed teeth without gingival recession, can eliminate this unsightly appearance. At times little or no root coverage is achieved, especially if the collars of the semilunar flap over the root prominences are torn. Even if the interproximal distance between the CEJ’s and the corresponding alveolar crest is 2.5mm or less generally only a couple of millimeters of root coverage can be expected with the semilunar flap + free gingival grafts and marginal tissue lifting regardless of the amount of gingival recession

Additional Considerations Wilcko et al first reported on the use of intramarrow penetrations in conjunction with SCTG’s for root coverage in 2005.23 Intramarrow penetration stimulates a regional acceleratory phenomenon (RAP) which provides an increase in hard and soft tissue reorganization activity in close approximation to the osseous insult. It also provides a pathway for the rapid efflux of pluripotential stem cells and capillary budding from the medullary spaces. Other than scaling of exposed root surfaces prior to flap reflection, no specific root preparation is needed. Large cervical restorations are removed following flap reflection and any sharp edges in the areas of cervical abrasion are smoothed.

CASE REPORTS Multiple sites of gingival recession are addressed with the FTF/SCTG approach utilized in all 6 cases presented in this paper. Additionally, a SLF/FGG with MTL approach is also used in the lower arches of 3 of the cases presented. One of the cases was treated in anticipation of possible orthodontic treatment, 1 of the cases was treated as part of the PAOO treatment, and 3 of the cases had previously had orthodontic treatment.

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Figure 6a: Right presurgical view of case 1.

Figure 6b: Left presurgical view of case 1.

Figure 6c: Preparation of right side of case 1.

Figure 6d: Preparation of left side of case 1.

Case 1 A female patient, age 54, presented with up to 6mm of Miller Class I-III facial gingival recession on multiple teeth (figures 6a,6b). Since less than a dozen teeth required root coverage grafting, FTFs/SCTGs were utilized in all of the involved areas. Preparation of the recipient sites involved interproximal intramarrow cuts (figures 6c,6d). Four thick FGG’s were removed from the palate and de-epithelialized to yield a total

of 4 SCTG’s and 4 FGG’s. The 4 SCTG’s were sutured at the recipient sites (figures 6e,6f) and FTF’s were coronally advanced. Several sutures were used at the donor sites to lessen the bleeding (figure 6g), and the donor sites were covered with an acrylic stent. The donor sites in the palate healed uneventfully (figure 6h). Healing of the recipient sites at 6 months after surgery can be seen in figures 6i and 6j.

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Wilcko et al

Figure 6e: SCTG secured on right side of case 1.

Figure 6f: SCTG secured on left side of case 1.

Figure 6g: Case 1 palatal donor site immediately post surgery.

Figure 6h: Case 1 palatal donor site healed after surgery.

Figure 6i: Right view of case 1 at 6 months after surgery.

Figure 6j: Left view of case 1 at 6 months after surgery. The Journal of Implant & Advanced Clinical Dentistry

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Figure 7a: Right presurgical view of case 2.

Figure 7b: Left presurgical view of case 2.

Figure 7c: Right view of RAP inducing intramarrow penetrations of case 2.

Figure 7d: Left view of RAP inducing intramarrow penetrations of case 2.

Case 2 A female patient, age 46, presented with Miller Class I and II gingival defects on the facials of 9 maxillary teeth (figures 7a, 7b). Because only 9 teeth were involved, it was decided to strictly utilize full thickness flaps and SCTG’s. Full thickness flaps were reflected at the 2 upper recipient sites. Sulcular and mesial vertical releasing incisions were utilized and intramarrow

penetrating was performed interradicularly (figures 7c, 7d). Three thick FGG’s were removed from the palate and de-epithelialized. The three resulting SCTG’s were then sutured at the recipient sites (figures 7e, 7f). The full thickness flaps were coronally advanced to passively cover the SCTG’s. Postsurgical results at 2 years are shown in figures 7g and 7h.

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Wilcko et al

Figure 7e: SCTG secured on right side of case 2.

Figure 7f: SCTG secured on left side of case 2.

Figure 7g: Right view of case 2 at 2 years after surgery.

Figure 7h: Left view of case 2 at 2 years after surgery.

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Case 3 A male patient, age 37, was referred for a periodontal evaluation in preparation for periodontally accelerated osteogenic orthodontics™ (PAOO™) treatment to include decrowding and space opening (figure 8a).24-26 Free gingival grafting had been performed in the lower anterior area 18 years earlier. There was presently 2 to 3 mm of Miller Class I marginal tissue recession on the facials of teeth #11 and #12. It was decided to perform the FTF/SCTG procedure in conjunction with the PAOO™ surgery. Following full thickness flap reflection and bone activation in the upper arch (figure 8b) a SCTG was harvested and sutured over the bony dehiscences on the facials of teeth #11 and #12 (figure 8c). Bone grafting material was then placed, as dictated by PAOO™ protocol, around the SCTG and over the activated bone (figure 8d). The flap was then coronally advanced to cover the SCTG (figure 8e). Final results 7 years after treatment are shown in figure 8f.


Wilcko et al

Figure 8a: Presurgical view of case 3.

Figure 8b: Full thickness flap reflection and bone activation in case 3.

Figure 8c: SCTG secured in case 3.

Figure 8d: Bone grafting material placed as dictated by PAOOâ&#x201E;˘ protocol.

Figure 8e: Flap coronally advanced to cover the SCTG in case 3.

Figure 8f: Results at 7 years after surgery. The Journal of Implant & Advanced Clinical Dentistry

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Figure 9a: Right presurgical view of case 4.

Figure 9b: Left presurgical view of case 4.

Figure 9c: Right view of RAP inducing intramarrow penetrations of case 4.

Figure 9d: Left view of RAP inducing intramarrow penetrations of case 4.

Case 4 A 57 year old female presented with Miller Class I and II gingival recession on the facial aspect of many of her upper and lower teeth (figures 9a,9b). Because of the large number of teeth requiring grafts, it was decided to do full thickness flaps with SCTG’s in the upper arch and semilunar flaps with FGGs and marginal tissue lifting in the lower arch. A total of 21 teeth were grafted, 9 teeth in the upper arch and 12 teeth in the lower arch. Following the preparation of the recipient

sites (figures 9c, 9d), 3 thick FGGs and 1 FGG of average thickness were removed from the palate. Utilizing a #15 Bard Parker blade each graft was split to provide a thinner FGG and a SCTG. This resulted in 3 thinner FGG’s and 3 SCTG’s, which in addition to the 1 FGG that was not split, provided for a total of 7 grafts. Figures 9e-9h show the grafts sutured at the recipient sites and covered with periodontal dressing. The results can be seen 6 months postoperatively in figures 9i and 9j.

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Wilcko et al

Figure 9e: Grafts secured on right side of case 4.

Figure 9f: Grafts secured on left side of case 4.

Figure 9g: Right view of periodontal dressing covering grafts of case 4.

Figure 9h: Left view of periodontal dressing covering grafts of case 4.

Figure 9i: Right view of case 4 at 6 months after surgery.

Figure 9j: Left view of case 4 at 6 months after surgery. The Journal of Implant & Advanced Clinical Dentistry

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DISCUSSION Predisposing anatomic considerations that may contribute to gingival recession include, but are not limited to, tooth position, gingival biotype, oral hygiene practices, destructive habits, smokeless tobacco use, bony dehiscence over root prominences, and an accompanying inadequate zone of gingival attachment.27-29 Very prominently positioned teeth are likely to have a bony dehiscence over the prominent root surface.30 Additionally, to complicate matters, the gingival attachment in these areas also tends to be narrower and thinner than what is found on teeth positioned more centrally in the alveolus.31 In such teeth, chronic gingival inflammation can readily result in the apical migration of the epithelial attachment and resultant gingival recession. If the patient has impeccable oral hygiene, on the other hand, the likelihood of gingival recession is minimized. Contemporary methods of treating gingival recession typically involve the use of SCTG’s. Due to the anatomy of the palate, a limited amount of SCTG is available for harvest. In most situations, SCTG harvest is restricted to an area distal to the canine and anterior to the mesial aspect of the first molar (Wara-aswapati). Straying beyond these limits may result in an inadequate SCTG harvest and increased risk of damaging the greater palatine artery. The limited availability of SCTG, even when harvested bilaterally, often restricts perio-plastic surgical treatment to a maximum of 6 teeth in a single sitting. Because of this, alternate allograft materials for soft tissue surgery have been introduced to the market. These materials, while of unlimited abundance, are technique sensitive and may provide results that degenerate over time. The

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technique described in this report provides a solution to the limited nature or autogenous tissue harvest. By obtaining very thick FGG’s and precisely splitting them, resultant SCTG’s and now thinner FGG’s may be utilized for coverage of up to 24 teeth in certain instances. This paper showed reports of 6 cases in which scores of mucogingival defects were successfully treated in a single sitting with autogenous tissue.

SUMMARY As many as a dozen areas of Miller Class I / II marginal tissue recession defects can be grafted utilizing the FTF/SCTG approach to achieve an enhanced zone of gingival attachment with root coverage. If more than a dozen areas of Miller Class I and II marginal tissue recession defects require gingival grafts, thick FGG’s can be split, with the resulting thinner FGG’s used in the lower arch in conjunction with a semilunar flap and marginal tissue lifting approach. A few millimeters of root coverage are possible and the enhanced zone of gingival attachment will have an acceptable appearance if multiple FGG’s are used in a continuous unerupted fashion over many teeth. The results of these 2 grafting approaches have proved stable with adequate oral hygiene. ● Correspondence: M. Thomas Wilcko, DMD 6074 Peach Street, Erie, PA 16509 Phone: (814) 868-3669 Fax: (814) 864-1368 Email: wilcko@velocity.net Website: www.fastortho.com


Wilcko et al

Disclosure The authors report no conflicts of interest with anything mentioned in this paper. References 1. Wennström J. Mucogingival therapy. Section 8. 1996 World Workshop in Periodontics. Ann Periodontol 1996; 1: 671-701. 2. Björn H. Free transplantation of gingival propria. Sven Tandlak Tidskr. 1963; 22: 684-689. 3. Miller P. Root coverage using a free soft tissue autograft following citric acid application. Part 1: Technique. Int J Periodontics Rest Dent 1982; 2: 65-70. 4. Raetzke P. Covering localized areas of root exposure employing the “envelope” technique. J Periodontol 1985; 56: 397-402. 5. Langer B, Langer L. Subepithelial connective tissue graft technique for root coverage. J Periodontol 1985; 56: 715-720. 6. Nelson SW. The subpedicle connective tissue graft. A bilaminar reconstructive procedure for the coverage of denuded root surfaces. J Periodontol 1987; 58: 95-102. 7. Harris RJ. The connective tissue and partial thickness double pedicle graft: A predictable method of obtaining root coverage. J Periodontol 1992; 63: 477-486. 8. Müller H, Eger T, Schorb A. Alterations of gingival dimensions in a complicated case of gingival recession. Int J Periodontics Rest Dent 1998; 18: 345-353. 9. Chambrone L, Chambrone L. Subepithelial Connective Tissue Grafts in the treatment of Multiple Recession-type of Defects. J Periodontol. 2006; 77(5): 909-916. 10. Allen AL. Use of the supraperiosteal envelope in soft tissue grafting for root coverage. II. Clinical results. Int J Periodontics Rest Dent 1994; 14: 302-315. 11. Zabalegui I, Sicilia A, Cambra J, Gil J, Sanz M. Treatment of multiple adjacent gingival recessions with the tunnel subepithelial connective tissue graft: A clinical report. Int J Periodontics Rest Dent 1999; 19: 199-206. 12. Blanes RJ, Allen EP. The bilateral pedicle flaptunnel technique: A new approach to cover connective tissue grafts. Int J Periodontics Rest Dent 1999; 19: 471-479. 13. Santarelli G, Ciacaglini R, Campanari F, Dinoi C, Ferraris S. Connective tissue grafting employing the tunnel technique: A case report of complete root coverage in the anterior maxilla. Int J Periodontics Rest Dent 2001; 21: 77-83.

14. Mahn D. Treatment of gingival recession with a modified “tunnel” technique and an acellular dermal connective tissue allograft. Pract Proced Aesthet Dent 2001; 13: 69-74. 15. Tözum TF, Dini FM. Treatment of adjacent gingival recession with subepithelial connective tissue grafts and the modified tunnel technique. Quintessence Int 2003; 34: 7-13. 16. Garglulo A, Wentz F, Orban B. Dimensions and relations of the dento-gingival junction in humans. J Periodontol 1961; 32: 261-267. 17. Maynard J, Wilson R. Physiologic dimensions of the periodontium significant to the restorative dentist. J Periodontol 1979; 50: 170-174. 18. Ingber J, Rose L, Caslet J. The “biologic width” – a concept in periodontics and restorative dentistry. Alpha Omegan 1977; December: 62. 19. Kois J. Altering gingival levels: the restorative connecti-Part1: biologic variables. J Esthetic Dent 1994; 6(1): 3-9. 20. De-Jacoby L, Ziafiro G, Ciancio S. The effect of crown margin location on plaque and periodontal health. Int J Periodontics Rest Dent 1989; 9(3): 147-205. 21. Nevins M, Skurow H. The intercrevicular restorative margin, the biologic width, and the maintenance of gingival margin. Int J Periodontics Rest Dent 1984; 4(3): 31-49. 22. Maynard J. Coronal positioning of a previously placed autogenous gingival graft. J Periodontol 1977; 4(3): 151-155. 23. Wilcko M, Wilcko W, Murphy K, Carroll W, Ferguson D, Miley D, Bouquot J. Full-thickness flap/subepithelial connective tissue grafting with intramarrow penetrations: three case reports of lingual root coverage. Int J Periodontics Rest Dent 2005; 25(6): 561-569. 24. Wilcko W, Wilcko M, Bouquot J, Ferguson D. Rapid orthodontics with alveolar reshaping: Two case reports of decrowding. Int J Periodontics Rest Dent 2001; 21: 9-19. 25. Wilcko W, Ferguson D, Bouquot J, Wilcko M. Rapid orthodontic decrowding with alveolar augmentation: case report. World J Orthodont 2003; 4: 197-505. 26. Wilcko M, Wilcko W, Bissada N. An evidencebased analysis of periodontally accelerated orthodontic and osteogenic techniques: a synthesis of scientific perspectives. Seminars in Orthodontics 2008; 21(4): 305-316.

28. Löst C. Depth of alveolar bone dehiscences in relation to gingival recession. J Clin Periodontol 1984; 11: 583-589. 29. Maynard JG, Ochsenbein D. Mucogingival problems, prevalence and therapy in children. J Clin Periodontol 1975; 6: 437-442. 30. Holbrook T, Oschsenbein D. Complete coverage of the denuded root surface with a one-stage gingival graft. Int J Periodontics Rest Dent 1983; 3: 9-27. 31. Wennström JL. Mucogingival considerations in orthodontic treatment. Seminars in Orthodontics 1996; 2(1): 46-54. 32. Batenhorst KF, Bowers GM, Williams JE. Tissue changes resulting from facial tipping and extrusion of incisors in monkeys. J Periodontol 1974; September: 660-668. 33. Artun J, Krogstad O. Periodontal status of mandibular incisors following excessive proclination: a study in adults with surgically treated mandibular prognathism. Am J Orthod Dentofacial Orthop 1987; 91: 225-232. 34. Wehrbein H, Bauer W, Diedrich P. Mandibular incisors, alveolar bone, and symphysis after orthodontic treatment. A retrospective study. Am J Orhtod Dentofacial Orthop 1996; 110(3): 239-246. 35. Nyman S, Karring T, Bergenholtz G. Bone regeneration in alveolar bone dehiscences produced by jiggling forces. J Periodontal Res 1982; 17: 316-322. 36. Karrying T, Nyman S, Thilander B, Magnusson I. Bone regeneration in orthodontically produced alveolar bone dehiscences. J Periodontal Res 1982; 17: 309-315. 37. Fuhrmann RAW. Three-dimensional evaluation of periodontal remodeling during orthodontic treatment. Seminars in Orthodontics 2002; 8(1): 23-28. 38. Reitan K. Some factors determining the evaluation of forces in orthodontics. Am J Orthodont 1957; 43: 32. 39. Reitan K. Tissue reaction as related to the age factor. Dent Rec 1954; 74: 271. 40. Reitan K. Continuous bodily movement and its histologic significance. Acta Odontol Scand 1947; 6:115. 41. Hirschfeld I. A study of skulls in the American Museum of Natural History in relation to periodontal disease. J Dent Res 1923; 5: 241.

27. Bernimoulin J, Curilivic Z. Gingival recession and tooth morbidity. J Clin Periodontol 1977; 4: 208-219.

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Maxillary Sinus Floor Augmentation: A Histologic and Histomorphometric Human Grafting Study Comparing Two Anorganic Bovine Bone Minerals

Gonshor et al

Aron Gonshor DDS, PhD1 • Yoon-Je Jang, DDS, PhD2 Abstract

Background: Autogenous grafts have been the “Gold Standard” in bone grafting. However, this often calls for a second surgical site and insufficient bone quantities. A need exists for a surgical technique that does not require autogenous bone harvesting and still results in sufficient bone formation within a relatively short time frame. Materials and Methods: This study compares two anorganic bovine bone minerals (ABBMs) - NuOss™ and Bio-Oss® - in an ongoing clinical human sinus floor augmentation project. Histology and histomorphometry were performed 5-10 months after grafting.

Results: age vital NuOss™ Residual NuOss™

Histomorphometry showed averbone content of 33% (±15) for and 33% (±17) for Bio-Oss®. graft content was 29% (±11) forand 24% (±17) for Bio-Oss®.

Conclusions: This study showed the similar osteoconductive properties of both NuOss™ and BioOss®. Clinical findings revealed a high bone density during the period of the post grafting study. The results confirm that grafting materials from a bovine source will produce reliable bone foundations for implant placement.

KEY WORDS: Bone grafts, maxillary sinus floor augmentation, anorganic bovine bone mineral, osteoblast(s), NuOss, Bio-Oss 1. Lecturer, McGill University, Department Oral and Maxillofacial Surgery, Montreal, Quebec, Canada 2. Clinical Assistant Professor, New York University, Department of Periodontics and Implant Dentistry, New York, New York, USA

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Gonshor et al

INTRODUCTION A lack of vertical height in the posterior maxilla often precludes implant placement. The loss of maxillary molars often results in very large reductions of bone volume in both horizontal and vertical directions, precluding implant placement.1 In addition to this quantitative loss there is also the factor of bone quality affecting the implant anchorage. Often there is little or no cortical bone in the posterior maxilla, as well as very low density cancellous bone. Both of these factors decrease the chance of achieving good primary stability during implant placement.2 Greater bone volume and height can be achieved by augmentation of the maxillary sinus floor, so as to provide a sufficient volume of bone for mechanical support. The technique for antral augmentation was developed by Tatum in the 1970s and reported in 1986,3 but the first clinical results were presented by Boyne and James.4 Apart from the technique itself, one of the key features in the success of the procedure involves the selection of the appropriate augmenting graft material.5 Autogenous bone has long been considered the gold standard in grafting procedures,6 but is often limited by the morbidity of a second surgical site and the frequent inadequate amounts of graft obtained.7 This has led to the use of a myriad of substitutes as grafting material, including allografts,8 coralline hydroxylapatite,9 synthetic calcium phosphates,10 anorganic bovine bone,11-13 or a combination of these materials.14 In particular, there has been considerable clinical evidence that anorganic bovine bone mineral (ABBM) gives very similar results to autogenous bone as a sinus grafting material.15 Froum et al11 showed similar implant survival rates when an ABBM was used

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with or without autogenous bone. Hising et al16 showed much higher implant survival rates when an ABBM was used alone (92.2%), than when it was used together with autogenous bone (77.2%). The present article highlights the use of two ABBMs- NuOss™ (ACE Surgical, Brockton, Mass, USA) and Bio-Oss® (Geistlich, Wolhusen, Switzerland) - in an ongoing clinical human sinus augmentation project. Histologic studies have shown that the ABBMs have bone-conductive properties17, 18 and that they have prolonged resorption times.19

MATERIALS AND METHODS Materials The inorganic component of bone is comprised of calcium-based minerals of apatite structure, mainly of carbonate apatite, containing small amounts of magnesium, sodium, potassium, chloride, etc. It has been demonstrated that the organic part of bone can be removed without significantly altering the native structure of the bone mineral.20 Methods have been developed that can produce this anorganic bone mineral from a bovine source, while maintaining the structure of the mineral similar to that in native bone. Essentially the method consists of a chemical extraction process and heat treatment to remove the organic components of the bone resulting in an anorganic bovine bone mineral, a natural calcium phosphate salt in a carbonate apatite structure. In the present study the ABBM granules were cancellous, in the 250 to 1000µ size. Patients This multicenter study took place from May, 2005 to February, 2007. Twelve patients (1 female, 11 males), with a mean age of 52 years (range 41 to 70) took part in the study.


Gonshor et al

Figure 1a: Cross sectional CBCT image after grafting.

Figure 1c: Cross sectional CBCT image after case completion.

Figure 1b: Panoramic CBCT image after grafting.

Figure 1d: Panoramic CBCT image after case completion.

There were 4 totally and 8 partially edentulous patients, all with bilateral posterior maxillary bone loss and sinus pneumatization, precluding the placement of implants. This created 22 maxillary sinus augmentations. The inclusion criterion was that the residual alveolar bone be no higher than 5mm, as determined by Computerized or Cone Bean Scans (figures 1a,1b). The average residual bone height was 3.8mm (Âą0.4mm). The exclusion criteria were smok-

ing, diabetes or autoimmune disease, abscess with soft-tissue swelling, oral bisphosphonates, and active sinus disease or sinus pathology. Each patient was given information about the study and gave written and oral consent. Surgical Procedure All of the patients underwent the sinus floor augmentation under local anesthetic. The surgical procedure has been described elsewhere.4 An

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Gonshor et al

Figure 2: ABBM placement into maxillary sinus.

incision was made in a slightly palatal portion of the residual ridge crest while vertical releasing incisions were made both anteriorly and posteriorly. The creation of a superiorly-lifted mucoperiosteal flap permitted visualization of the lateral maxillary bone with a view of the buccal sinus wall. Using diamond-tipped burs, a window was created in the lateral maxillary buccal wall, revealing the Schneiderian membrane. The latter was separated from the underlying bone so as to create a submembrane cavity into which the graft material was placed. There was no infracturing of the buccal wall. In each case, the treatment was to augment the sinuses with the ABBM - NuOss™ on one side and Bio-Oss® on the other (figure 2). In one of the patients platelet rich plasma (PRP) was mixed with the ABBM’s. Implants were placed at a later date. In all cases, after the graft material was placed, the window opening was covered with a long acting resorbable collagen membrane (RCM-6, ACE Surgical, Brockton, Mass, USA). Closure was performed with 3.0 Vicryl® sutures (Johnson and Johnson, Langhorne, PA, USA) in both continuous and horizontal-mattress fashion. Core Biopsies After an average of 6.4 months of healing, cores were taken for histologic and histomorphometric analysis (figure 3) and dental implants were placed. Biopsy cores were taken with trephines of 2.7 mm internal diameter (3.5 mm external diameter). The Biopsies were left within the trephine and placed in 10% neutral buffered formalin for fixation.

Figure 3: Histologic core sample.

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Histological Preparation Histological preparations were performed at


Gonshor et al

Figure 4a: High resolution histology of bone formation in graft with Bio-Oss®

Figure 4b: High resolution histology of bone formation in graft with NuOss™

the Department of Oral Pathology, Yonsei University College of Dentistry, Seoul, Korea and at the Periodontal Bone Center, McGill University, Montreal, Quebec, Canada. Upon receipt, specimens were dehydrated with a graded series of alcohols for 9 days. The specimens were then infiltrated with a light-curing embedding resin. After a further 20 days, the specimens were embedded and polymerized by 450 nm light. The specimens were then prepared by the cutting/grinding method of Donath21 and Rohrer.22 The cores were then polished to a thickness of 45-65 µm, followed by a final polish with 0.3 micron alumina polishing paste. The slides were stained with Hematoxylin-Eosin (H&E) and coverslipped for histologic analysis by means of bright field and polarized microscopic evaluation.

The cores were digitized at the same magnification using a Leica DMR HC and a Jenoptic ProgRes C14 Digital camera. Histomorphometric measurements were completed using Bioquant Nova Prime Bone Morphometry, version 6.50.10 (Bioquant Image Analysis Corp. - Nashville, Tenn, USA). Parameters evaluated were the total area of the core, the percentage of new bone formation, and the percentage of residual graft material. The remainder of the area was considered as being soft-tissue, void or osteoid. The primary slide evaluated for each specimen was from the most central region of the obtained core. No comparison was made between the apical and coronal sections.

Histomorphometry Following non-decalcified histologic preparation, the cores were evaluated morphometrically at McGill University, Montreal, Quebec, Canada.

RESULTS Histology The histologic results are represented in figures 4a and b. In all cases, even those that had an 8-10 month healing period between grafting and core removal, residual particles of ABBM

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Gonshor et al

were still clearly visible. For both Bio-Oss® and NuOss™ there was significant bone growth in intimate contact with the grafted particles. The bone was mostly of the woven variety, but there was also ample evidence of more mature lamellar bone formation. The newly-formed bone could be easily distinguished from the grafted ABBM as the bovine bone mineral exhibited empty lacunae, with no osteocytic nuclei and no lamellar layering. This was contrasted by the new viable bone with osteocyte nuclei. In addition, there was bridging of new bone between particles - a cardinal sign of active bone growth. The ABBM particles were often thick and jagged-edged as opposed to the new viable bone which exhibit long lamellae with indefinite boundaries. There was also evidence of connective tissue distributed amongst the graft particles and new bone trabeculae, containing blood vessels, collagenous fibers and fibroblasts. There were no signs of inflammation. Although there were few signs of active osteoclasts, the new bone ingrowth was evidence of slow replacement of the grafted particles by new viable bone. Histomorphometry The histomorphometric analysis revealed remarkably similar results for both ABBM’s. The average percentage of new vital bone was 33%, with a large standard deviation in the 24-29% range. The ABBM amounts were also close in value, with an average of 24% (±11) for NuOss™ and 29% (± 17) for Bio-Oss®. The amount of soft tissue was also similar, with 39% (±21) for NuOss™ and 43% (± 14) for Bio-Oss®. Notwithstanding a period of 5 to10 months before removing the bone cores, the duration of waiting time was not a significant

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factor affecting the percentage of new bone formation. It would seem that individual healing response, rather than the time the bone material was in place, had the greatest effect on the ABBM integration. There were also large variations in bone healing around the ABBM’s regardless of age and sex of the subjects.

DISCUSSION Bio-Oss and NuOss are both sterile anorganic bovine bone materials with porosity in the range of 75-80%. The inner macropores of ABBM’s are similar to natural cancellous bone.23 No B-cell or T-cell inflammatory responses have been reported with the use of the ABBM.24 BioOss has been shown to be biocompatible with oral osseous tissue, fulfilling a major requirement of an osteoconductive material. The degradation of these materials has been studied extensively. When ABBM’s were first used, they were considered as bioresorbable materials that would be replaced by autogenous bone over time. More recent studies have shown histological evidence that ABBMs are not resorbed with time. Hallman et al,19 working with human subjects, demonstrated that residual ABBM content did not decrease from 6 months to 3 years after grafting. Other authors have confirmed this slow resorption, with very few resorption lacunae,25 or almost no resorption at all.26 Working with Bio-Oss, Avera et al27 showed particles present after 44 months, and Piattelli et al confirmed particle presence after 4 years.18 Instead, it appears that the graft particles become embedded in the newly generated lamellar bone, creating a more radiopaque, dense bone than would be the case if the ABBM had resorbed.28 In fact, it has been suggested that the resistance


Gonshor et al

of ABBM’s to resorption may help in maintaining initial stability in the augmented areas.11,29 As has been described elsewhere,13,30 in this study newly generated bone was seen in intimate contact with the ABBM particles. The length of wait from grafting to core samples was not identifiable as a factor in the percentages of new bone creation. It may be assumed that the variation in percentage is more a factor of individual healing and regeneration response. The percentages were also not related to patient age or sex. The amount of vital bone is nevertheless substantial for that post-graft time period, rising to above 30%. In addition there is still a high percentage of non-vital bone remaining. This is consistent with the general fact that these bovine minerals resorb slowly.25 Lastly, the remaining marrow and fibrous tissue showed no signs of inflammatory response or giant cell invasion. This highlights the fact that both of these materials are well accepted by the recipient. There was no significant difference in percentages of vital or non-vital bone between the case where PRP was added and the remaining cases in the study. This is not unexpected, since the effect of PRP is most pronounced when it is associated with autogenous tissue, which contains living cells. Its effect on non-vital grafts such as the ABBM’s is not significant.31 The inclusion criteria used for sinus floor augmentation are important determinants of the eventual clinical result. It is likely that with the decreasing amount of residual bone below the sinus floor, the role played by the grafted bone in achieving implant support becomes increasingly important. In that regard, Jensen and Greer32 showed a 100% survival rate when the residual bone was 7mm and a 29% survival

rate when only 3mm of residual bone remained. The histomorphometric analysis showed that the amount of new bone formation for the two bone materials was about 33%, with the nonvital particle percentage around 26%. These results are close to the findings of other studies with using autogenous bone alone as a graft material in sinus augmentation26 or in defects around dental implants.33 All of these studies, as well as the present results, indicate that the use of this bovine material will lead to predictable bone formation.

CONCLUSION This study showed the osteoconductive properties of both NuOss™ and BioOss® and confirms their effectiveness as natural bone grafting substitutes. The clinical findings revealed significant bone formation during the period of the post grafting study. The results highlight and confirm the fact that grafting materials from a bovine source will produce reliable bone foundations for implant placement. ● Correspondence: Dr Aron Gonshor 4980 Glencairn Ave Montreal, Quebec Canada, H3W 2B2 Phone: 514 941 4502 email: arongonshor@gmail.com

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Gonshor et al

Disclosure The authors report no conflicts of interest with anything mentioned in this article. References 1. Watzek G, Ulm CW, Haas R (eds). The Sinus Bone Graft. Anatomic and physiologic fundamentals of sinus floor augmentation. Chicago: Quintessence, 1999. 2. Misch CE. Effect on treatment plans, surgical approach, healing, and progressive bone loading. Int J Oral Implantol 1990; 6: 23-31. 3. Tatum OH. Maxillary and sinus implant reconstructions. Dental Clin North Am 1986; 30: 207-229. 4. Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg 1980; 38(8): 613-616. 5. Jensen OT, Shulman LB, Block MS, Iacono VJ. Report of the Sinus Consensus Conference of 1996. Int J Oral Maxillofac Implants 1998;13 Suppl:11-45. 6. van den Bergh JPA, ten Bruggenkate CM, Krekeler G, Tuinzing DB. Sinus floor elevation and grafting with autogenous iliac crest bone. Clin Oral Implants Res 1998;9:429-435. 7. Kalk WW, Raghoebar GM, Jansma J, Boering G. Morbidity from iliac crest bone harvesting. J Oral Maxillofac Surg 1996;54:1424-1429. 8. Nishibori M, Betts NJ, H. S, Listgarten MA. Short term healing of autogenous and allogenic bone grafts after sinus augmentation: A report of 2 cases. J Periodont 1994;65:958-966. 9. Smiler DG, Holmes RE. Sinus lift procedure using porous hydroxyapatite: A preliminary clinical report. J Oral Implantol 1987;13:239253. 10. Zijderveld SA, Zerbo IR, van den Bergh JPA, Schulten EAJM, ten Bruggenkate CM. Maxillary sinus floor augmentation using a beta-tricalcium phosphate (Cerasorb) alone compared to autogenous bone grafts. Int J Oral Maxillofac Implants 2005;20:432-440. 11. Froum SJ, Tarnow DP, Wallace SS, Rohrer MD, Cho SC. Sinus floor elevation using anorganic bovine bone matrix (OsteoGraf/N) with and without autogenous bone: a clinical, histologic, radiographic, and histomorphometric analysis-Part 2 of an ongoing prospective study. Int J Periodontics Restorative Dent 1998;18:528-543. 12. Froum SJ, Wallace SS, Cho S-C, Elian N, Tarnow DP. Histomorphometric comparison of a biphasic bone ceramic to anorganic bovine bone for sinus augmentation: 6 to 8-month postsurgical assessment of vital bone formation. A pilot study. Int J Periodontics Restorative Dent 2008;28:273-281.

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13. Yildirim M, Spiekermann H, Biesterfeld S, Edelhoff D. Maxillary sinus augmentation using xenogenic bone substitute material Bio-Oss in combination with venous blood. A histologic and histomorphometric study in humans. Clin Oral Implants Res 2000;11:217-219. 14. Moy PK, Lundgren S, Holmes RE. Maxillary sinus augmentation: Histomorphometric analysis of graft materials for maxillary sinus floor augmentation. J Oral Maxillofac Surg 1993; 51: 857-862 15. Hallman M, Sennerby L, Lundgren S. A Clinical and Histologic Evaluation of Implant Integration in the Posterior Maxilla After Sinus Floor Augmentation with Autogenous Bone, Bovine Hydroxyapatite, or a 20:80 Mixture. Int J Oral Maxillofac Implants 2002;17:635-643. 16. Hising P, Bolin A, Branting C. Reconstruction of severely resorbed alveolar crests with dental implants using a bovine bone mineral for augmentation. Int J Oral Maxillofac Implants 2001;16:90-97. 17. Hallman M, Lundgren S, Sennerby S. Histological analysis of clinical biopsies taken 6 months and 3 years after maxillary sinus floor augmentation with 80% bovine hydroxyapatite and 20% autogenous bone mixed with fibrin glue. Clin Implant Dent Relat Res 2001;2:87-96. 18. Piattelli M, Favero GA, Scarano A, Orsini G, Piattelli A. Bone reactions to anorganic bovine bone (Bio-Oss) used in sinus augmentation procedures: A histologic long-term report of 20 cases in humans. Int J Oral Maxillofac Implants 1999;14:835-840. 19. Hallman M, Cederlund A, Lindskog S, S. L, Sennerby L. A clinical histologic study of bovine hydroxyapatite in combination with autogenous bone and fibrin glue for maxillary sinus floor augmentation. Results after 6-8 months of healing. Clin Oral Implants Res 2001;12:135-143. 20. Johnson G, Mucalo M, Lorier M. The processing and characterization of animalderived bone to yield materials with biomedical applications: part 1: modifiable porous implants from bovine condyle cancellous bone and characterization of bone materials as a function of processing. J Mater Sci Mater Med 2000;11:427-441. 21. Donath K, Breuner G. A method for the study of undecalcified bones and teeth with attached soft tissues. The Sage-Schliff (sawing and grinding) technique. J Oral Pathol 1982;11:318-326. 22. Rohrer M, Schubert C. The cutting-grinding technique for histologic preparation of undecalcified bone and bone-anchored implants. Improvements in instrumentation and procedures. Oral Surg Oral Med Oral Pathol 1992;74:73-78.

23. Berglundh T, Lindhe J. Healing around implants placed in bone defects treated with Bio-Oss: An experimental study in the dog. Clin Oral Implants Res 1997;8:117-124. 24. McAllister B, Margolin M, Cogan A, Taylor M, Wollins J. Residual lateral wall defects following sinus grafting with recombinant human osteogenic protein-1 or Bio-Oss in the chimpanzee. Int J Periodontics Restorative Dent 1998;18:227-239. 25. Storgard-Jensen S, Aaboe M, Pinholt E, Hjorting-Hansen E, Melsen F, Ruyter I. Tissue reaction and material characteristics of four bone substitutes. Int J Oral Maxillofac Implants 1996;11:55-66. 26. Valentini P, Abensur D, Densari D, Graziani JN, Hammerle C. Histological evaluation of Bio-Oss in a 2-stage sinus floor elevation and implantation procedure. A human case report. Clin Oral Implants Res 1998; 9: 59-64. 27. Avera SP, Stampley WA, McAllister BS. Histologic and clinical observations of resorbable and nonresorbable barrier membranes used in maxillary sinus graft containment. Int J Oral Maxillofac Implants 1997;12:88-94. 28. Schlegel A, Donath K. Bio-Oss: A resorbable bone substitute? J Long Term Eff Med Implants 1998;8:201-209. 29. Scarano A, G. P, Piattelli M, Piattelli A. Osseointegration in a Sinus Augmented With Bovine Porous Bone Mineral: Histological Results in an Implant Retrieved 4 Years After Insertion. A Case Report. J Periodontol 2004;75:1161-1166. 30. Skoglund A, Hising P, Young C. Clinical and histologic examination in humans of the osseous response to implanted natural bone mineral. Int J Oral Maxillofac Implants 1997;12:194-199. 31. Froum S, Wallace S, Tarnow D, Cho S. Effect of Platelet-Rich Plasma on Bone Growth and Osseointegration in Human Maxillary Sinus Grafts: Three Bilateral Case Reports. Int J Periodontics Restorative Dent 2002;22:4553. 32. Jensen O, Greer R, . (eds). Immediate placing of osseointegrating implants into the maxillary sinus augmented with mineralized cancellous allograft and Gore-Tex: Secondstage surgical and histological findings. Chicago: Quintessence 1992. 33. Hammerle C, Chiantella G, Karring T, Lang N. The effect of a deproteinized bovine bone mineral on bone regeneration around titanium dental implants. Clin Oral Implants Res 1998;9:151-162.


Wilcko et al


Does your bone grafting material measure up? Improvements in clinical and radiographic parameters in the GEM 21S® pivotal trial compare favorably with or exceed, documented outcomes for other regenerative therapies in studies examining defects with similar baseline characteristics.1,2,3,4 Radiographic Percent Bone Fill (BF%)

Radiographic Linear Bone Growth (LBG)

40

20

4.0 3.7

2.6 2.0

1.0

1.1*

CAL Gain (mm)

Mean LBG (mm)

57 Mean % BF

Clinical Attachment Level (CAL) Gain

3.0

60

3.0 2.7* 2.0

14* 0

GEM 21S®

0

Enamel Matrix Derivative (EMD)

GEM 21S®

Enamel Matrix Derivative (EMD)

0

GEM 21S®

Enamel Matrix Derivative (EMD)

*EMD results at 8 months, GEM 21S® results at 6 months

To learn more, please visit us online at www.osteohealth.com or call 1-800-874-2334 View prescribing information: www.osteohealth.com/documents/52.pdf

IMPORTANT SAFETY INFORMATION GEM 21S® Growth-factor Enhanced Matrix is intended for use by clinicians familiar with periodontal surgical grafting techniques. It should not be used in the presence of untreated acute infections or malignant neoplasm(s) at the surgical site, where intra-operative soft tissue coverage is not possible, where bone grafting is not advisable or in patients with a known hypersensitivity to one of its components. It must not be injected systemically. The safety and effectiveness of GEM 21S® has not been established in other non-periodontal bony locations, in patients less than 18 years old, in pregnant or nursing women, in patients with frequent/excessive tobacco use (e.g. smoking more than one pack per day) and in patients with Class III furcations or with teeth exhibiting mobility greater than Grade II. In a 180 patient clinical trial, there were no serious adverse events related to GEM 21S®; adverse events that occurred were considered normal sequelae following any periodontal surgical procedure (swelling, pain). For full prescribing information, go to www.osteohealth.com or call 1-800-874-2334 and a copy will be sent to you. References: 1. Nevins M, Giannobile WV, McGuire MK, Mellonig JT, McAllister BS, Murphy KS, McClain PK, Nevins ML, Paquette DW, Han TJ, Reddy MS, Lavin PT, Genco RJ, Lynch SE. Platelet Derived Growth Factor (rhPDGF-BB) Stimulates Bone Fill and Rate of Attachment Level Gain. Results of a Large Multicenter Randomized Controlled Trial. J Periodontol 2005; 76: 2205-2215. 2. Heijl L, Heden G, Svardstrom G, Ostgren. Enamel matrix derivative (EMDOGAIN) in the treatment of intrabony periodontal defects. J Clin Periodontol 1997; 24: 705-714. 3. Zetterstrom O, Andersson C, Driksson L, et al. Clinical safety of enamel matrix derivative (EMDOGAIN) in the treatment of periodontol defects. J Clin Periodontol 1997; 24: 697-704. 4. See full prescribing infromation for more detail. Emdogain® is a registered trademark of BioVentures BV Corporation. ©COPYRIGHT Osteohealth Company 2008. All rights reserved. OHD235e Rev. 9/2009.


Preservation of Buccal Bone Plate after Immediate Implant Placement/Function with the Flapless Approach: A Case Report

Novaes et al

Arthur B. Novaes Jr., DDS, MScD, DSc1 • Rafael R. de Oliveira, DDS, MScD2 Valdir A. Muglia, DDS, MScD, DSc3 Abstract

Background: Immediate placement of implant into an extraction socket provides both patient and the clinician with the advantages of significantly decreasing treatment time by minimizing the surgical stages and helping to maximize the esthetic outcome by preventing alveolar ridge and gingival resorption. Methods: An immediate implant was placed through flapless approach in order to replace the hopeless right central incisor due to an extensive periapical lesion. After implant placement, a minimally functional fixed provisional restoration was inserted. A CT scan analysis

was conducted 12 months later in order to verify the status of the cervical buccal plate, as well as the regression of the periapical lesion. Results: The 12-month post-operative CT shows the complete healing of the periapical lesion in addition to preservation of the cervical buccal plate. Conclusion: The benefit of the combination of immediate implant placement/function and flapless approach can make possible the maintenance of cervical buccal bone plate.

KEY WORDS: Dental implants, immediate function/loading, computed tomography, dental esthetics 1. Professor & Chairman of Periodontology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. 2. Graduate Student of Periodontology, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. 3. Assistant Professor of Prosthodontics, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.

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INTRODUCTION One of the most challenging procedures in implant dentistry is the replacement of teeth in the esthetic zone. Today, the development of an esthetic restoration that matches the adjacent natural dentition has become the focus of attention in implant dentistry. Evaluation of the periodontal tissues is critical to achieve an esthetic outcome as the alveolar bone has a tendency to resorb following tooth loss and the soft tissues generally shrink.1-4 This is especially obvious in the anterior region where thin buccal bone plates are often present.5,6 This loss of bone and soft tissue lead to esthetic issues that may compromise the restorative outcomes.7-9 Observations on cadaver specimens indicated that following tooth loss in the maxilla, the height of the ridge reduces and the crest shifted palatally.10 Tylman & Tylman stated that following the removal of teeth, the buccal alveolar bone plate resorbed much faster than the palatal plate.11 A paradigm shift from the restoration-driven implant placement to a tissue-related, esthetically driven approach has recently favored the concept of immediately implants placed into extraction sites.12,13 This concept helps to preserve soft and hard tissue architecture and therefore reduces the potential risk for the resorptive processes at the alveolar ridge. A goal of current research in implantology is to improve patient satisfaction and the esthetics of restored dental implants. Immediate placement of an implant into an extraction socket provides both patient and clinician with the advantages of significantly decreasing treatment time by minimizing the surgical stages and helping to maximize the esthetic outcomes by reducing alveolar ridge and gingival resorption. However, immediate post-extraction implant

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Figure 1: Periapical radiograph of the right central incisor.

placement often results in two major problems: reduction of primary initial stability and soft tissue ingrowth during the healing period.14 Most often, the initial stability can be preserved by placing an implant that is longer that the extracted root or wider in diameter in the apical third. The maintenance of the existing gingival architecture is essential in achieving an esthetic result, and for this purpose, the flapless approach may be indicated. Therefore, the prevention of soft tissue ingrowth and/or gingival recession around the implant is a prerequisite in esthetically driven implant dentistry. Recent investigations have reported high survival rates of immediately provisionalized single-tooth implants in the maxilla


Novaes et al

Figure 2: Cross-sectional tomography image showing an apical hypodense area and the cervical position of the buccal bone plate.

after a follow-up of 12 to 18 months.15-17 This approach guides the healing and the maturation of the soft tissues, favoring formation of the papillae through the orientation of the emergency profile shaped by the temporary prosthesis. Moreover, the loss of bone after tooth extraction, followed by additional bone loss in the first year after implant loading, could severely modify the architecture of hard and soft tissues, compromising the final esthetic outcome of implant therapy. The aim of this case report is to demonstrate through computed tomography (CT) scan analysis, the possibility of maintenance of the cervical buccal bone plate after immediate implant placement followed by immediate function protocol.

Figure 3: Negative image of figure 2 .

CASE DESCRIPTION AND RESULTS The patient was diagnosed through radiographic examination with a hopeless maxillary right central incisor (figure 1) due to an extensive apical lesion and long post and core restoration. The treatment plan was to replace the tooth with an implantsupported crown using the flapless approach and immediate provisionalization. The patient signed an informed consent form and treatment was initiated. At the first periodontal visit, the compromised periodontal sites were detected, comprehensive oral hygiene and full-mouth scaling and root planning was performed. Following the achievement of satisfactory levels of plaque con-

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Figure 4: Flapless approach. Implant placed 1-1.5mm away from the buccal bone wall.

Figure 5: Full-thickness flap elevated .

trol the patient was scheduled for the surgery. Based on the information gained from initial radiographs and bone mapping, a diagnostic waxup was made on articulated casts. The final position of the gingival margins and the apicocoronal dimensions of the crown were established in this preoperative diagnostic procedure by taking into account the thickness of the gingiva at the site of implantation and the existing gingival architecture around the natural teeth. Based on the wax-up, a CT scan of the maxilla (figures 2, 3) and a three dimensional (3D) model were obtained. This allowed for the construction of a surgical template and precise planning of the surgical and prosthetic treatment. Simulation of the implantation surgery was performed and it was possible to individualize the abutment and to fabricate the provisional restoration. Following review of all planning procedures, the surgery was scheduled. The surgical procedure was performed under local anesthesia with mepivacaine chlorhydrate with epinephrine 1:100,000. Antimicrobial treatment (amoxicillin 875 mg) was given every 12 hours for 10 days, starting 24 hours prior to surgery and was programmed so

that the third dose was taken one hour before the surgery. A flapless surgery was carried out with atraumatic extraction of the hopeless tooth using a periotome. After the root was mobilized, it was carefully removed with forceps in a manner that minimized trauma to soft tissue and alveolar bone. The extraction socket was thoroughly debrided, bone walls were instrumented with bone chisels in order to remove any soft tissue tags and stimulate the opening of the marrow cavities, and lastly irrigated with a saline solution. The socket walls and apex were carefully inspected to determine the morphology of the socket and to establish if the buccal plate was intact. Upon decision that the site was adequate for the implantation, the surgical template was inserted and the implant site was sequentially enlarged with pilot and spiral drills according to the standard surgical protocol for an implant 4.5mm in diameter and 15.0mm in length (Xive S Plus, Dentsply Friadent, Mannheim, Germany). A blasted and acid-etched self-tapping screw-type implant was placed 1 to 1.5mm away from the buccal bone wall (figure 4). The implant was anchored in the floor of nasal cavity and was

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Figure 6: A bioactive glass material grafted over the thin apical buccal plate.

Figure 7: Flap closure and provisional restoration in position.

found to be stable. Based on the CT scan and clinical inspection, a thin buccal bone plate in the apical third of the implant site was a concern. An apicoectomy-type incision was made at the mucogingival junction and a full-thickness flap was raised leaving the coronal aspect of the gingiva undisturbed (figure 5). A bioactive glass material (Biogran, Biomet 3i, Palm Beach Gardens, FL, USA) was grafted over the thin buccal plate (figure 6) and flap closure was achieved using 5-0 nylon sutures. In sequence, the gap between implant and bone walls was also grafted with the bioactive glass. Immediately following implant placement, the initial restorative treatment was initiated. The provisional restoration which was fabricated based on the previously performed prototyping was then cemented for refinements on contour and occlusal adjustment (figure 7). In sequence, a periapical radiograph was taken using the longcone paralleling technique to check the adaptation of the prosthetic components and restoration. The patient was instructed to eat a soft diet for 4 weeks post surgery. Analgesics were given on the day of surgery and postoperatively for the first 3

days if needed. The patient was placed in on a strict follow-up regime until soft tissue healing was complete. The final implant impression was made after 3 months and a definitive ceramic abutment (Cercon, Dentsply Friadent, Mannheim, Germany) was connected to the implant and the definitive metalfree ceramic restoration was cemented (figure 8). A new CT scan was performed 12 months after implant placement in order to verify the status of buccal bone plate as well as the osseointegration of the implant (figures 9, 10). The implant was stable during all observation periods and no complications such as screw loosening, ceramic fracture, or pain during chewing were registered. The 12-month post-operative CT scan showed complete healing of the periapical lesion and preservation of the cervical buccal plate.

DISCUSSION Providing patients with optimal esthetics remains challenging when teeth require replacement with implant-supported crowns. However, it can be a source of great satisfaction for the patient and clinician when the outcome is excellent. Mainte-

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Figure 8: The definitive restoration.

nance of soft tissue contours is a requisite in gaining an ideal esthetic result. In turn, maintenance of soft tissue contours is dependent on extraction techniques that generate less trauma to bone and soft tissues followed by providing interim support for the overlying soft tissue. Optimal support of the soft tissues during healing following tooth extraction in the esthetic region might best be provided through immediate implant placement and insertion of an immediate minimally functional fixed provisional and the flapless approach. AraĂşjo et al.17 demonstrated that marked hard tissue alterations occurred during healing following tooth extraction and implant installation in fresh sockets using full thickness flap. The modeling in the marginal defect region was accompanied by marked attenuation of the dimensions of both buccal and lingual bone plate. However in addition to other factors such as position of the implants within the sockets, the results may be due to the full thickness flap that was raised. Loss or reduction of the bony walls due to tooth extraction is not a new observation.18 The healing process following tooth removal results in more pronounced resorption on the buccal than the lingual/ palatal aspects of the ridge.19 Further, the process that resulted in tissue reduction seemed to be more

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Figure 9: Twelve month cross-sectional CT.

evident during the initial phase of wound healing than during later periods following tooth removal. Johnson20 reported that most dimensional alterations, horizontal as well vertical, occurred during the first three months of healing.20 Carlsson et al evaluated tissue changes through the analysis of human biopsy specimens of the anterior maxillary extraction sites.21 During an observation period of 3 to 210 days, the authors reported that the first sign of osteoclastic activity was after 7 days and after about 20 days, additional resorption resulted in a considerable thinning of the buccal bone plate. After about 40 days, practically all of the original plate was resorbed and partially replaced


Novaes et al

Figure 10: Negative image of figure 9.

by new bone. This new bone, however, was not continuous and lamellar as the original one. More recently, Botticelli et al assessed dimensional alterations that occurred in the alveolar ridge during a 4-month period following implant placement in fresh extraction sockets.22 The authors concluded that the buccal bone dimension had undergone horizontal resorption that amounted to about 56% while the corresponding reduction of the lingual/palatal bone plate was 30%. This loss is greatly due to the full thickness flap that is frequently used. It is well documented that surgical trauma which includes the separation of the periosteum and the rupture of its connective

tissue attachment at the bone surface will induce an acute inflammatory response which, in turn, will mediate resorption of the surface layer of the alveolar bone in the exposed area.5,23-25 Wilderman et al, when studying the healing of mucogingival flaps and its effects on the bone, found that within the first week, 5mm of buccal bone height was lost.26 Half of this lost was recovered during the healing process, but after 185 days, a loss of 2.5mm in height was realized. This loss in height of the buccal bone occurred in the presence of the tooth and the periodontal ligament, proving that the loss in buccal bone height is due to the mucogingival flap that compromises the vascularization of the periosteum to the bone. Similar findings regarding the healing of mucogingival flaps and the sequence of events was shown by Kon et al.27 The buccal plate in the cervical area is very thin and mainly cortical. It has no vascularization or marrow spaces, so it depends on the vascularization that comes in part from the periodontal ligament and the periosteum. When tooth extraction is performed, a good part of vascularization of the buccal plate is lost. Additionally, if a full thickness flap is raised, the remaining vascularization of the buccal plate is removed leading to a resorption process.28 With the flapless approach, the vascularization from the periosteum to the thin buccal plate is preserved, minimizing the possibility of resorption. ● Correspondence: Arthur Belém Novaes Jr. Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Avenida do Café s/n, 14040-904, Ribeirão Preto, SP, Brasil. novaesjr@forp.usp.br

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Disclosure The authors report no conflicts of interest with anything mentioned in this paper. References 1. Spear F. Maintenance of the interdental papilla following anterior tooth removal. Pract Periodontics Aesthet Dent 1999; 11:2 1-28. 2. Carlsson G, Bergman B, Hedegard B. Changes in contour of the maxillary alveolar process under immediate dentures. A longitudinal clinical and x-ray cephalometric study covering 5 years. Acta Odontol Scand 1967; 25: 45-75. 3. Becker W, Ochsenbein C, Tibbetts L, Becker B. Alveolar bone anatomic profiles as measured from dry skulls. Clinical ramifications. J Clin Periodontol 1997; 24: 727-731. 4. Salama H, Salama M, Garber D, Adar P. The interproximal height of bone: a guidepost to predictable aesthetic strategies and soft tissue contours in anterior tooth replacement. Pract Periodontics Aesthet Dent 1998; 10: 11311141. 5. Brägger U, Pasquali L, Kornman K. Remodeling of interdental alveolar bone after periodontal flap procedures assessed by means of computerassisted densitometric image analysis (CADIA). J Clin Periodontol 1988; 15: 558-564. 6. Wllderman M. Exposure of bone in periodontal surgery. Dent Clin North Am 1964; 3: 23-26. 7. Buser D, Brägger U, Lang N, Nyman S. Regeneration and enlargement of jaw bone using guided tissue regeneration. Clin Oral Implants Res 1990; 1: 22-32. 8. Dahlin C, Andersson L, Linde A. Bone augmentation at fenestrated implants by an osteopromotive membrane technique. A controlled clinical study. Clin Oral Implants Res 1991; 2: 159-165. 9. Jovanovic S, Spiekermann H, Richter E. Bone regeneration around titanium dental implants in dehisced defect sites: a clinical study. Int J Oral Maxillofac Implants 1992; 7: 233-245. 10. Rogers W, Applebaum E. Changes in the mandible following closure of the bite with particular reference to edentulous patients. J Am Dent Assoc 1941; 28: 1573. 11. Tylman S, Tylman S. Theory and Practice of Crown and Bridge Prosthodontics 1960; 4th edition, 69–71. St. Louis: The C.V. Mosby Company.

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12. Lazzara R. Immediate implant placement into extraction sites: surgical and restorative advantages. Int J Periodontics Restorative Dent1989; 9: 332-43. 13. Parel S, Triplett R. Immediate fixture placement: a treatment planning alternative. Int J Oral Maxillofac Implants 1990; 5: 337-345. 14. Huys L. Replacement therapy and the immediate post-extraction dental implant. Implant Dent 2001; 10: 93-102. 15. Chaushu G, Chaushu S, Tzohar A, Dayan D. Immediate loading of single-tooth implants: immediate versus non-immediate implantation. A clinical report. Int J Oral Maxillofac Implants 2001; 16: 267-272. 16. Andersen E, Haanaes H, Knutsen B. Immediate loading of single-tooth ITI implants in the anterior maxilla: a prospective 5-year pilot study. Clin Oral Implants Res 2002; 13: 281-287. 17. Araújo M, Sukekava F, Wennström J, Lindhe J. Tissue modeling following implant placement in fresh extraction sockets. Clin Oral Implants Res 2006; 17: 615-624. 18. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study. Int J Periodontics Restorative Dent 2003; 23: 313-323. 19. Pietrokovski J, Massler M. Alveolar ridge resorption following tooth extraction. J Prosthet Dent 1967; 17: 21–27. 20. Johnson K. A study of the dimensional changes occurring in the maxilla following tooth extraction. Aust Dent J 1969; 14: 241-244. 21. Carlsson G, Thilander H, Hedegard B. Histologic changes in the upper alveolar process after extractions with or without insertion of an immediate full denture. Acta Odontol Scand. 1967; 25: 21-43. 22. Botticelli D, Berglundh T, Lindhe J. Hardtissue alterations following immediate implant placement in extraction sites. J Clin Periodontol. 2004; 31: 820-828. 23. Wilderman M. Repair after a periosteal retention procedure. J Periodontol 1963; 34: 487–503.

24. Staffileno H, Levy S, Gargiulo A. Histologic study of cellular mobilization and repair following a periosteal retention operation via split thickness mucogingival flap surgery. J Periodontol 1966; 37: 117–131. 25. Wood DL, Hoag PM, Donnenfeld OW, Rosenberg DL. Alveolar crest reduction following full and partial thickness flaps. J Periodontology 1972; 43: 141–144. 26. Wilderman MN, Wentz FM, Orban BJ. Histogenesis of repair after mucogingival surgery. J Periodontol 1960; 31: 283-299. 27. Kon S, Novaes AB, Ruben MP, Goldman HM. Visualization of the microvascularization of the healing periodontal wound. IV. Mucogingival surgery: full thickness flap. J Periodontol 1969; 40: 441-456. 28. Araújo MG, Lindhe J. Dimensional ridge alterations following tooth extraction. An experimental study in the dog. J Clin Periodontol 2005; 32: 212-218.


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Giulio et al


Subperiosteal Dental Implants: A 25 Year Retrospective Survival Evaluation

Giulio et al

Antonio T. Di Giulio1 • Giancarlo Di Giulio1 • Enrico Gallucci2 Abstract

Background: Making long term retentive dentures for patients with inadequate bone for endosseous dental implants is a challenge. In such situations, utilization of subperiosteal dental implants is a viable yet often overlooked option. The aim of this study was to determine the long term survival rates of subperiosteal dental implants placed between 1985-2008. Material and methods: All candidates for subperiosteal dental implants underwent computed tomography (CT) scans to reproduce the bone crest in maximum detail. A stereolithographic model for both maxilla and mandible was constructed, upon which a subperiosteal prosthesis was then constructed.

Results: 66 patients received a chromecobalt total subperiosteal implant between 1984 and 1995. 54 patients received a titanium total subperiosteal implant between 1996 and 2008. Statistical analysis of KaplanMeier demonstrated a survival rate of 95.5% at 7 years and 89.1% at 20 years for chromecobalt implants. Titanium subperiosteal dental implants had a survival rate of 81.1% at 7 years. Conclusions: This study demonstrates that subperiosteal dental implants offer a viable alternative to endosseous dental implants when inadequate bone is present. Presurgical evaluation with computerized tomography and utilization of stereolithic models allows for reduced surgical time and properly fitting structures.

KEY WORDS: Subperiosteal dental implants, chrome-cobalt, titanium, maxilla, mandible, stereolithography 1. San Babila Day Hospital, via Stoppani 36, Milano, Italy 2. Farmaco-Biologico Department, Università degli Studi di Bari, Italy

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INTRODUCTION In 1965, Brånemark1 placed the first titanium dental implant into a human maxilla ushering in a new era in the field of dentistry. Decades of data provide overwhelming evidence that implantology is a safe therapeutic intervention and provides recipients with function, aesthetics, and comfort following a minimally invasive surgical approach. Furthermore, computer-assisted navigation systems, which improve intra-operative safety by preventing damage to nerves and other critical structures, have recently been successfully applied to implant dentistry. At a technical level, this has led implantology to achieve maximum precision. However, although surgical dental implant placement is safe and rigorously programmed, it is sometimes not without complications deriving from the many variables involved in the procedure. Though there are many ways of making implants feasible, inadequate osseous structures sometime render this option inaccessible. In such situations, utilization of subperiosteal dental implants is a viable yet often overlooked option. The first subperiosteal implant in Europe was carried out by Dahl2 back in 1940 followed by Goldberg and Gershkoff3 later utilizing this treatment modality in the USA. Linkow4 further advanced use of the subperiosteal implant with the design referred to as the “tripodal mandibular subperiosteal implant.” This article focuses on over 25 years of the authors’ clinical experience with subperiosteal dental implants including the surgical procedure, post-operative follow up, and statistical analysis of long term survival.

MATERIALS AND METHODS A retrospective survival study of subperiosteal dental implants placed from 1984 to 2008 exam-

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Figure 1: Maxillary stereolithographic model.

Figure 2: Mandibular stereolithographic model.

ined 120 consecutive patients. A total of 65 female patients (mean age of 51.5 ± 11.0 years) and 55 males (mean age of 49.3 ± 12.0 years) were evaluated. All patients treated in this study were completely edentulous and typically pre-


Giulio et al

Figure 3: Example of maxillary subperiosteal implant fit.

Figure 4: Suturing following maxillary subperiosteal implant delivery.

sented with severely resorbed maxillas and/or mandibles. Smokers and those suffering from chronic systemic conditions such as diabetes, cardiovascular disease, severe osteoporosis, or those undergoing chemo/radiation therapies were not included in this study. Candidates for subperiosteal implant therapy received panoramic radiographs and computed tomography (CT) scans with 64 multislices (General Electric Co, USA) to reproduce osseous structures in maximum detail. Such pretreatment analysis allowed us to become familiar with the patient’s three-dimensional (3D) bony architecture and critical anatomical structures so as to plan the subperiosteal implant. This analysis allowed for fabrication of maxillary and mandibular stereolithographic models used in constructing custom fabricated subperiosteal dental implants. The exacting detail of the models allowed for fixtures that intimately adapted to the patients’ osseous anatomy before any surgical procedure was ever undertaken. The structure of the maxillary subperiosteal den-

tal implant, constructed of either chrome-cobalt or titanium, has a palatal bar connected to two vestibular bars simulating roots of the molars (figure 1). The framework of the mandibular subperiosteal dental implant (figure 2) embraces the alveolar crest, reminiscent of the tripodal mandibular subperiosteal implant proposed by Linkow.4 All patients were treated under local anesthesia with occasional use of sedation. An incision was made on the alveolar crest and mucoperiosteal flaps were elevated to facilitate fixture delivery. It should be noted that before this procedure was introduced (2003), the protocol described by Linkow4 and Moore5 had been followed. With the newer procedure, the fit of the implant was evaluated by pulling it to make sure of perfect contact with the bone. Before suturing of the gingiva, the implant was covered with hydroxyapatite (n=34 patients) or demineralized bone allograft (n=15 patients), whereas in another 5 subjects no graft was used (Figures 3 and 4). Postsurgical instructions were given to the patient and follow-up CT’s

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and panoramic radiographs were performed in all cases. A 4-month healing period was allowed prior to placing prosthetic restorations for full function. The evolution of the treatment was evaluated by pulling the implant in all possible directions and additional radiographs were taken to identify bone apposition over the abutment. Figure 5 shows healed bone covering portions of the subperiosteal dental implant from figure 3. Annual check-ups were required to verify the success of the implant. The parameters assessing implant success were based on subjective and objective clinical criteria such as: 1) absence of clinically-detectable implant mobility; 2) absence of pain; 3) absence of inflammation; 4) comfort of patient; 5) bleeding on probing; 6) pocket-probing depth; 7) absence of foreign body sensation. Statistical analysis of survival rates at 7 and 20 years were performed applying the method of Kaplan-Meier.6 Graphpad PrismTM version 3.0 (Graph Pad Software, Inc, http://www.graphpad.com) was used to calculate survival fractions using the product limit and report the uncertainty of the fractional survival as standard error calculated by the method of Greenwood. Furthermore, comparison among different survival curves was automatically performed by means of logrank test. Success rates were calculated as a percentage.

RESULTS Sixty six patients received chrome-cobalt total subperiosteal implants between April 1984 and February 1995. Of those, 51.5% (n=34) were female and 48.5% (n=32) were male patients. 43 of the 66 implants were placed in the maxilla and 23 in the mandible. The total number of failed chrome-cobalt subperiosteal implants during the total observation period was seven.

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Figure 5: New bone covering subperiosteal implant from figure 3.

Five implants failed in males (3 maxillary, 2 mandibular) and 2 failed in females (1 maxillary, 1 mandibular). Allergy to chrome-cobalt was determined to be the cause of 5 implant failures while other causes included: a) 1 case of menopausal osteoporosis; b) 1 case of excessive long term osseous resorption in an elderly subject (73 years of age). In the latter two cases, the implants were removed after 13 and 19 years respectively. Statistical analysis was performed on the chrome-cobalt study cohort minus deaths and patients failing to respond to recall. Survival rate at 7 years of observation was 95.5% while survival rate at 20 years was 78.1% (figure 6). Fifty four patients received titanium total subperiosteal implants between September 1996 and March 2008. Of those, 57.4% (n=31) were female and 42.6% (n=23) were male patients. Some patients in this study cohort received a


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Figure 6: Kaplan–Meier estimate of survival rates of chrome-cobalt implants as a function of time since installation.

treatment modification as select cases were grafted with hydroxyapatite or demineralized bone allograft. As this was a newer procedure, only seven year survival rate was determined. The total number of failed titanium subperiosteal implants during this observation period was four (2 male, 2 female). The causes of failure were determined to be: a) 3 cases of severe osteoporosis; b) 1 implant fracture after one year of function. Statistical analysis was performed on the titanium study cohort minus deaths and patients failing to respond to recall. Survival rate at 7 years of observation was 87.1%. As a side note, it should be mentioned that use of demineralized bone allograft did not occur until the period of 20022008. Although follow up on these cases is short compared with the previous subperiosteal implant techniques, it is worth noting that 100% of these cases have survived and are still in function. A comparison of the survival curves of chromecobalt and titanium subperiosteal dental implants is reported in figure 7. The analysis gives a value

Figure 7: Kaplan–Meier estimate of survival rates of chrome-cobalt and titanium implants as a function of time since installation.

of χ2 = 2.43 and a p-value of P = 0.12, indicating that the two curves are not significantly different.

DISCUSSION Multiple studies have shown that the various endosseous dental implants available today successfully osseointegrate and have good long term prognoses. In most of these studies, patients typically have adequate bone for implant fixture delivery or osseous structures conducive to reasonable grafting procedures. For patients with inadequate mandibular and/or maxillary bone, treatment with endosseous dental implants is not always feasible. In such situations, treatment with subperiosteal dental implants may be the patient’s only option for fixation of dental prostheses.7,8 This study reported on survival rates of 120 subperiosteal dental implants placed over 24 years (1985-2008). The survival rates seen in this study are comparable to results published by other authors who reported a survival rates of 87%, 98%, 79%, 78%, and 98.7% over approxi-

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mately 10 years, respectively.9-12 Although these survival rates are less than those typically reported with endosseous dental implants, one must remember that most cases treated with subperiosteal dental implants have osseous structures of an often compromised nature. In many of these cases, treatment with endosseous dental implants was neither a feasible nor a safe option. It is worth noting that in some patients who showed chrome-cobalt allergy or severe osteoporosis, their implants lasted a mean of 5.0 ± 2.3 years after surgery. Complications due to chromecobalt allergy were overcome by the use of titanium, which has excellent biocompatibility and high corrosion resistance.13-16 Additionally, the recent addition of demineralized bone allograft to the subperiosteal implant procedure has improved survival rates at the 7 year benchmark. Further evaluation at the 20 year benchmark will provide additional data for long term survival of contemporary use of subperiosteal dental implants. The successful delivery of subperiosteal dental implants is aided by three-dimensional computed tomography reconstructions enabling the precise reconstruction of the patient’s osseous profile upon which the subperiosteal implant is to be placed. Particular mention should be made of the stereolithographic technique, which enables a model to be created from a CT data set. This template of the mandible and/ or maxilla provides precise guidance for subperiosteal implant design and delivery in vivo.

CONCLUSION For patients with severe inadequacies of mandibular and/or maxillary bone, treatment with endosseous dental implants is not always feasible and the subperiosteal dental implant offers

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a viable alternative treatment option. Over a 24 year retrospective evaluation, the survival rates of subperiosteal dental implants seen in this and other studies prove this treatment modality to be a feasible treatment option in select patient populations. The most important aspect for long term success of subperiosteal dental implants is precise manufacturing of the implant to fit the patient’s osseous profile. Additionally, proper prosthetic restoration and periodic follow up visits are required. All of the patients seen in this study profess complete satisfaction with their implants in terms of improvements to their social life and stomatognathic functionality. This is of considerable importance owing to the relatively young age of our patients. Indeed, to paraphrase Brånemark’s famous remark, “nobody should have to live a nightly bedtime drama with his/her overdentures in a glass of water.” ● Correspondence: Dr. Enrico Gallucci Dipartimento Farmaco-Biologico Università degli Studi di Bari via E. Orabona 4, 70126 Bari, Italy Tel/Fax: +39 0805442796 Email: gallucci@farmbiol.uniba.it


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Disclosure The authors report no conflicts of interest with anything mentioned in this article. Acknowledgements The authors would like to thank their colleague Anthony Green for proofreading and providing linguistic advice. The following collaborators: Engineer F. Davolio, Radiologist A. Zerbi, Technician E. Puntieri are gratefully acknowledged for their collaboration. References 1. Brånemark P. Available at: http://en.wikipedia.org/wiki/Dental_ implant#cite_ref-2 2. Dahl G. Dental implant and superplants. Rassegna Trimestrale Odontoiatria 1956; 4: 25-36. 3. Goldberg N, Gershkoff A. Implant lower denture. Dent Dig 1949; 55: 490494. 4. Linkow L, Wagner J, Chanavaz M. Tripodal mandibular subperiosteal implant: basic sciences, operational procedure, and clinical data. J Oral Implantol 1998; 24:16-36. 5. Moore JD, Hansen PA. A descriptive 18-year retrospective review of subperiosteal implants for patients with severely atrophied edentulous mandible. J Prosthet Dent 2004;92:145-150. 6. Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Amer Stat Assoc 1958; 53: 457-48. 7. Kurtzman G, Schwartz K. The subperiosteal implant as a valuable long-term treatment modality in the severely atrophied mandible: a patient’s 40-years case history. J Oral Impantol 1995; 21: 35-39. 8. Kusek E. The use of laser technology (ER;CR:YSGG) and stereolithography to aid in the placement of a subperiosteal implant: A case study. J Oral Implantol 2009; 35: 5-11. 9. James R. Subperiosteal implant design. NY J Dent 1983; 53: 407-14. 10. Golec T, Krauser J. Long-term retrospective studies on hydroxyapatite coated endosteal and subperiosteal implants. Dent Clin North Am 1992; 36: 39-65. 11. Yanase R, Bodine R,Tom J, White S. The mandibular subperiosteal implant denture: a prospective survival study. J Prosthet Dent 1994; 71: 369-74. 12. Bodine R, Yanase R, Bodine A. Forty years of experience with subperiosteal implant dentures in 41 edentulous patients. J Prosthet Dent 1996; 75: 33-44. 13. Albrektsson T, Hansson H, Ivarsson B. Interface analysis of titanium and zirconium bone implants. Biomaterials 1985; 6: 97-101. 14. Steinemann S, Eulenberg J, Maeusli P, Schroeder A. Biological and Biochemical Performance of Biomaterials, 1st edition, Elsevier, Amsterdam 1986; 409-414 . 15. Rae T. The biological response to titanium and titanium-aluminiumvanadium alloy particles I. Tissue culture studies. Biomaterials 1986; 7: 30-36. 16. Lindigkeit J. Titanium and titanium alloys: Fundamentals and Applications, Wiley-VCH Verlag GmbH & Co. KGaA 2005; 453-466.

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Winter et al

Dental 3D Imaging Centers - Usage and Findings: Part III – Bifid Canals and Other Deviations of the Inferior Alveolar Nerve

Alan A. Winter, DDS1 • Kouresh Yousefzadeh, DDS2 • Alan S. Pollack, DDS3 Michael I. Stein, DMD4 • Frank J. Murphy, DDS5 Christos Angelopoulos, DDS6 Abstract Background: This is part 3 of a 5 part study evaluating data obtained from dental referral usage of radiological labs for three dimensional (3D) anatomical scans. The purpose of this current study was to gather data on bifid mandibular canals and other deviations of the inferior alveolar nerve (IAN). Methods: Data from 500 consecutive patients sent to i-dontics dental radiological centers from 9 centers locations in 3 states were evaluated. Of these patients, the current study evaluated 296 mandibles for the following: the incidence of bifid branches of the inferior alveolar canal, the number of branches present when the IAN was observed to split, laterality of the bifid canals, and the location of the bifid canal in relation to the mental foramen (anterior, equal to, or posterior). Results: 296 mandibular scans were included in the study. Of these scans, 186 patients (62.84%)

did not demonstrate evidence of a bifid canal. In contrast, 110 patients (37.16%) had one or more bifid canals. Of the 110 patients demonstrating bifid canals, 56 (50.9%) had one bifid canal, 37 (33.6%) had two canals, and 17 (15.45%) had three or more canals. Slightly more than half (55.45%) of bifid canals were unilateral. Two thirds (67%) of the unilateral bifid canals were on the right side of the mandible; one third (33%) of the unilateral bifid canals were on the left side of the mandible. 9 bifid canals (8.18%) were located at the mental foramen, 94 (85.45%) were posterior to the mental foramen, and 7 (6.36%) continued anterior to the mental foramen. Conclusions: The incidence of bifid mandibular canals (37%) from the current study was greater than that reported in other studies. Presurgical identification of bifid canals reduces risk of damage to vital structures and may explain difficulty in obtaining local anesthesia in certain situations.

KEY WORDS: Cone beam computed tomography, inferior alveolar nerve, bifid canals mandible, dental implants 1. Assistant Clinical Professor, Department of Periodontics and Implant Dentistry, New York University College of Dentistry 2. Private practice, New York, USA 3. Private practice, New York, USA 4. Private practice, New York, USA 5. Private practice, New York, USA 6. Director Maxillofacial Dental Radiology and Associate Professor of Clinical Dentistry, Columbia School of Dental Medicine

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IntRODuCtIOn The recent advent of cone beam computed tomography (CBCT) technology has vastly increased the diagnostic options for dental treatment. While this technology is continually improving in terms of quality, equipment size, and cost, most dental offices do not own CBCT scanners at this time. Accordingly, many practices currently refer patients to freestanding dental radiological labs for three dimensional (3D) anatomical scans. The purpose of this series of studies was to determine how and for what reason dentists currently utilize dental 3D imaging centers. Part one of this study series evaluated demographic data and the reasons why patients were referred for 3D evaluation. Part two of this study series evaluated anatomical features of the lingual artery in relation to dental implant treatment. The purpose of this current study was to gather data on bifid mandibular canals and other deviations of the inferior alveolar nerve (IAN). A bifid mandibular canal is a relatively uncommon anatomical variation typically seen in less than 1% of the population. The incidence of bifid canals has been evaluated with both conventional panoramic and computed tomography (CT) images. Findings indicate that the canals may split in different positions along the length of the IAN and one branch may be smaller than the other.1,2 Langlais et al3 reported a 0.95% prevalence of bifid mandibular canals while Sanchis4 reported an incidence of 0.4% in an evaluation of 2,012 mandibles. Multiple studies agree that the bifid anatomical variations need to be identified when surgical procedures such as removal of impacted third molars, insertion of dental implants, and osteotomies, are to be performed.5-9 Once bifid canals are identified, the local

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Figure 1: Prevalence of bifid canals in 296 patients.

Figure 2: Of the mandibles demonstrating bifid canals, 50.9% had one branch, 33.6% had branches, and 15.45% had three or more branches.

anesthetic injection technique, prosthetic design, and surgical procedures can be modified to prevent pain and discomfort during treatment procedures10 and ultimately improve final outcomes.

MAtERIALS AnD MEtHODS CBCT scans of the dental arches from 500 consecutive patients taken in 9 centers located in 3 states were uploaded to the main pro-


Winter et al

tinuous with the main inferior alveolar canal in each slice. For consistency, all studies were examined by a single examiner (KY).

RESuLtS

Figure 3: 55% (61/110) of bifid canals were unilateral while nearly 46% (49/110) were identified bilaterally. The majority of unilateral canals were located on the right side of the mandible (41/61).

cessing center of a single dental radiological practice (i-dontics, llc., New York, N.Y.) which is limited to taking and processing 3D CT images for the dental community. Scans were taken on either i-CAT scanners (8 centers) or on a (1) NewTom 3G scanner. All studies were converted to SimPlantâ&#x201E;˘ (Materialise, Glen Burnie, MD). When not specified, the data was converted to SimPlantâ&#x201E;˘ version 10. In the current study, 296 of the 500 scans were of the mandible. These scans were evaluated for the following: the incidence of bifid branches of the inferior alveolar canal, the number of branches present when the IAN was observed to split, laterality of the bifid canals, and the location of the bifid canal in relation to the mental foramen (anterior, equal to, or posterior). All CBCT studies were made into 1.0 mm slides and viewed both in the coronal and transaxial planes. To be counted as a bifid canal, each offshoot had to be con-

number 296 mandibular scans were included in the study. Of these scans, 186 patients (62.84%) did not demonstrate evidence of a bifid canal. In contrast, 110 patients (37.16%) had one or more bifid canals. Of the 110 patients demonstrating bifid canals, 56 (50.9%) had one bifid canal, 37 (33.6%) had two canals, and 17 (15.45%) had three or more canals. Laterality Slightly more than half (55.45%) of bifid canals were unilateral. Two thirds (67%) of the unilateral bifid canals were on the right side of the mandible; one third (33%) of the unilateral bifid canals were on the left side of the mandible. Location of the Bifid Canal 9 bifid canals (8.18%) were located at the mental foramen, 94 (85.45%) were posterior to the mental foramen, and 7 (6.36%) continued anterior to the mental foramen.

DISCuSSIOn The incidence of bifid canals has been reported at less than one percent3,4 and the split of the mandibular nerve may be of unequal sizes.1,2 Regardless of the frequency of identifying bifid canals, various authors have identified the surgical risks and complications that may be experienced when they are encountered, including an inability to obtain profound anesthesia using a local anesthetic.5-9

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Figure 4: The majority of the bifid canals (85%) ended posterior to the mental foramen, while 8 percent terminated at the mental foramen, and 6% extended anterior the mental foramen.

In order to achieve standardization and consistency, the authors agreed as to what constitutes a bifid canal as identified on the 3D image: any branch that appeared as a continuous radiolucent canal extending from the inferior alveolar nerve. All slices were 1mm in thickness and all bifid canals were viewed and appeared to emanate from the IAN in three planes: axial, coronal, and sagittal. Once the parameters were defined, one researcher (YK) examined and identified all of the bifid canals noted in this study, which

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were then verified by a second author (AW). The significance of the findings in this study matters relative to the size and location of the bifid canals, and what clinical procedure is anticipated. Concerning operative dentistry, it has been postulated that bifid nerves may explain why anesthesia is not as profound as it should be when employing a local anesthetic. When encountered, infiltration of the local anesthetic to anesthetize these extra branches of the IAN may help achieve greater local anes-


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Figure 5: Arrow indicates a small bifid canal that starts and ends distal to tooth #31. A larger canal can be seen anterior to tooth #18.

Figure 6: The left bifid canal is highlighted in red, illustrating 3 bifid canals.

thesia. When planning implant surgery, it is helpful to identify if any bifid canals exist in the surgical site. Encountering these extra canals may not only contribute to unwanted local paresthesias, but may also explain unusual bleeding that emanates from the alveolar bone.10-11 Figures 5 and 6 illustrate an example of multiple canals as they were identified in this study. While the widest branch, which is anterior to tooth #18, is evident on the panoramic slice, smaller canals are highlighted in Figure 6.

Note the arrow in Figure 5 that highlights a bifid canal. Careful inspection will note additional canals emanating from the right IAN. Mention must be made of the value of 3D images identifying normal and abnormal structures when compared to 2D images. Figure 7 is a panoramic image (formatted in a 15 mm trough) taken on a patient that was referred to the CT lab after an implant was inserted that resulted in paresthesia in the patient. Figure 8 highlights a bifid branch of the IAN

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Figure 7: Patient presented after an implanted was inserted in the #30 site resulting in paresthesia.

Figure 8: A bifid nerve rises from the IAN and was traumatized by the implant insertion.

that was traumatized by an implant. This aberrant branch was not evident in the panoramic view due to the dense cortical bone. Traditional 2D imaging, both panoramic and periapical film, is limited in revealing key anatomic structures that are obscured by thick buccal and/or lingual bone. In this example, using 3D imaging prior to

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implant insertion would have identified the bifid (aberrant) branch and altered the surgical site.

COnCLuSIOn The incidence of bifid mandibular canals (37%) from the current study was greater than that


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reported in other studies. Presurgical identification of bifid canals reduces risk of damage to vital structures and may explain difficulty in obtaining local anesthesia in certain situations. ●

Correspondence: Dr. Alan Winter a.winter@i-dontics.com

Disclosure: Support for this study was generously given by NobelBiocare, Mahwah, NJ and Imaging Sciences Inc., Hatfield, PA. References: 1. Mardini S, Gohel A. Exploring the Mandibular Canal in 3 Dimensions. An Overview of Frequently Encountered Variations in Canal Anatomy. AADMRT Newsletter, Fall 2008. 2. Jacobs R, Mraiwa N, vanSteenberghe D, Gijbels F, Quirynen M. Appearance, location, course, and morphology of the mandibular incisive canal: an assessment on spiral CT scan. Dentomaxillofacial Radiology 2002; 31:322-327. 3. Langlais RP, Broadus R, Glass B. Bifid mandibular canals in panoramic radiographs. J Am Dent Assoc 1985; 110:923-926. 4. Sanchis JM, Penarrocha M, Soler F. Bifid mandibular canal. J Oral Maxillofac Surg 2003; 61:422–424. 5. Rouas P, Nancy J, Bar D. Identification of double mandibular canals: literature review and three case reports with CT scans and cone beam CT. Dentomaxillofacial Radiology 2007; 36:34-38. 6. Naitoh M, Hiraiwa Y, Aimiya H, Gotoh M, Ariji Y, Izumi M, Kurita K, Ariji E. Bifid Mandibular Canal in Japanese. Clinical Science and Techniques Implant Dentistry 2007; 16:24-32. 7. Claeys V, Wackens G. Bifid mandibular canal: Literature review and case report. Dentomaxillofacial Radiology 2005; 34:55-58. 8. Auluck A, Ahsan A, Pai KM, Shetty C. Anatomical variations in developing mandibular nerve canal: A report of three cases. Neuroanatomy 2005; 4:28–30. 9. Dario LJ. Implant placement above a bifurcated mandibular canal: A case report. Implant Dent 2002; 11:258-261. 10. Auluck A, Ahsan A, Pai KM, Mupparapu M. Multiple mandibular nerve canals: Radiographic observations and clinical relevance. Report of 6 cases. Quintessence International 2007; 38:781-787. 11. Winter AA. Bleeding from a Nutrient Canal: A Case Report. NY State Dent J 1980; 46:646.

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