GBR with Induced Periodontal Regeneration

Padatrow et al post-operative results have been maintained for one to two years. An important local factor in The Journal of Implant & Advanced Clinical Dentistry the development of peri-implantitis in the patients treated appears to have been excess subgingi- ATTENTION val cement on implant and abutment surfaces. This observation underscores the need for care- AUTHORS ful control of luting agents and thorough supra- and subgingival removal of excess cement when For complete details placing cement-retained crowns on implants. regarding publication in Correspondence: JIACD, please refer Pradeep Adatrow, DDS, MSD, MPH to our author guidelines at 875 Union Ave, C 312 Department of Periodontology the following link: University of Tennessee College of Dentistry http://www.jiacd.com/ Memphis, TN- 38163 Phone: 901-448-4756 authorinfo/ Fax: 901-448- 6751 author-guidelines.pdf Email: [email protected] or email us at: Disclosure [email protected] The authors report no conflicts of interest with anything mentioned in this article. 48 Vol. 2, No. 1 February 2010 References: 1. Lindhe J, Meyle J. Peri-implant diseases: Consensus Report of the Sixth European Workshop on Periodontology. J Clin Periodontol. Sep 2008;35(8 Suppl):282-285. 2. Zitzmann NU, Berglundh T. Definition and prevalence of peri-implant diseases. J Clin Periodontol. Sep 2008;35(8 Suppl):286-291. 3. Heitz-Mayfield LJ. Peri-implant diseases: diagnosis and risk indicators. J Clin Periodontol. Sep 2008;35(8 Suppl):292-304. 4. Listgarten MA, Lang NP, Schroeder HE, Schroeder A. Periodontal tissues and their counterparts around endosseous implants [corrected and republished with original paging, article orginally printed in Clin Oral Implants Res 1991 Jan-Mar;2(1):1-19]. Clin Oral Implants Res. Jul-Sep 1991;2(3):1-19. 5. Ruggeri A, Franchi M, Marini N, Trisi P, Piatelli A. Supracrestal circular collagen fiber network around osseointegrated nonsubmerged titanium implants. Clin Oral Implants Res. Dec 1992;3(4):169-175. 6. Berglundh T, Lindhe J, Jonsson K, Ericsson I. The topography of the vascular systems in the periodontal and peri-implant tissues in the dog. J Clin Periodontol. Mar 1994;21(3):189-193. 7. Claffey N, Clarke E, Polyzois I, Renvert S. Surgical treatment of peri-implantitis. J Clin Periodontol. Sep 2008;35(8 Suppl):316-332. 8. Leonhardt A, Dahlen G, Renvert S. Five-year clinical, microbiological, and radiological outcome following treatment of peri-implantitis in man. J Periodontol. Oct 2003;74(10):1415-1422.

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JIACD Continuing EducatiJoIAnCD Continuing Education Osteocyte Density in Woven and Lamellar Peri-Implant Bone Raquel R. M. Barros, DDS, MScD1 2 Adriano Piattelli, DDS, MScD, DSc3 4 Abstract Background: Considering the possible asso- prepared and histomorphometry was used to ciation between osteocytes and bone remodel- evaluate the osteocyte index in the groups. ling, this study evaluated the osteocyte density in woven and lamellar bone around loaded implants. Results: The differences in osteo- cyte density between woven and lamel- Method: Bilateral mandibular premolars of lar bone were statistically significant 6 dogs were extracted, and after 12 weeks in all 4 groups, but not between them. each dog received 8 Morse-cone connection implants immediately loaded. Four experi- Conclusion: Woven bone presented significant mental groups were constituted: subcrestal higher number of osteocytes when compared to with interimplant distance of 2mm and 3mm; lamellar bone and this might be explained by dif- and equicrestal with interimplant distance of 2 ferent bone remodeling rates. However, different mm and 3 mm. After eight weeks, the animals implant placement depths and interimplant dis- were euthanized, the retrieved specimens were tances did not influence the osteocyte number. KEY WORDS: dental implants; lamellar bone; osteocyte density; osteocytes; woven bone Learning Objectives After reading this article, the reader should be able to: 1. Discuss aspects of early 2. Discuss the significance of peri-implant bone remodeling osteocyte density in peri-implant following dental implant placement. bone crestal bone loss. 1. Graduate student of Periodontology, Department of Bucco-Maxillo-Facial Surgery and Traumatology and Periodontology, School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil. 2. Professor and Chairman of Periodontology, Department of Bucco-Maxillo-Facial Surgery and Traumatology and Periodontology, School of Dentistry of Ribeirão Preto, University of São Paulo, SP, Brazil. 3. Professor of Oral Pathology and Medicine, Dental School, University of Chieti-Pescara, Italy. 4. Research Fellow, Department of Oral Pathology and Medicine, Dental School, University of Chieti-Pescara, Italy.. The Journal of Implant & Advanced Clinical Dentistry 51

JIACD Continuing Education INTRODUCTION to undergo remodelling more rapidly than lamel- lar bone,16 and considering the possible exist- As a dynamic environment, functional adap- ence of specific mechanisms by which osteocytes tation is required for bone survival.1,2 The influence bone resorption and remodelling,17 mechanical integrity of bone is a result of the osteocyte density may play an important role in replacement of old or damaged bone by newly determining the biological properties of woven formed bone over time.2,3 Concerning implant bone.17 Hernandez et al,17 for example, reported dentistry, loading seems to play a decisive role that lacunar density between woven and lamel- in bone formation and bone mineral density.4 lar bone can differ by as much as 40-100%. The function of the osteocyte in skeletal health Based on this, the aim of the present study and disease has been a focus of recent study.5 was to evaluate osteocyte density in woven Osteocytes are not only the most abundant cells and lamellar peri-implant bone around loaded in mature bone, but also the longest-lived and the implants in a dog model, investigating the influ- best-connected in the mineralized matrix.6 They ence of different interimplant distances and seem to have a putative role in mechanotrans- depth placement on osteocyte cellularity. duction, actively participating in the modulation of bone remodeling and turnover.1,2,7 There is a the- MATERIALS AND METHODS ory that osteocytes may sense external mechani- cal loads, which could be understood as a vital This research was conducted in parallel with function for the maintenance of bone mass and another study that evaluated the influence of dif- architecture.8 The osteocyte cell bodies are posi- ferent interimplant distances and different place- tioned in lacunae, and they are in contact with ment depths of adjacent implants in papillae neighboring osteocytes via long slender cell pro- formation and crestal bone resorption through cesses located in canaliculi, which are filled with clinical/radiographic analysis18 and histomor- interstitial fluid.9,10 When bones are loaded, the phometric evaluation19 in a dog model. In a pre- resulting strain acts as a driving force that causes vious study20 it was reported that osteocytes a flow of interstitial fluid trough the lacuno-can- surrounding implants are important in the regu- alicular network.11 This fluid flow is sensed by lation of bone remodeling. In the present study osteocytes, which respond by producing signal- the objective was to evaluate if loaded implants ing molecules that stimulate osteoblast recruit- placed in different positioning conditions will ment while inhibiting osteoclast recruitment and influence osteocyte presence and morphology. activity, resulting in a gain of bone mass.12,13 How- ever, this process remains partially understood. The study protocol was approved by the Ethical Committee of the School of Dentistry of Ribeirão Woven bone is produced in response to a Preto, University of São Paulo, SP, Brazil (Process need of quick bone formation, thus it lacks regu- 07.1.122.53.8) and involved two surgical interven- lar orientation and organization of the collagen- tions that were performed in six young adult male ous matrix.14-16 This type of structure is thought mongrel dogs, weighing approximately 20 kg. to result from accelerated matrix production by the osteoblasts.15 Moreover, woven bone tends The animals presented intact maxillas, no general occlusal trauma, and no oral viral or fun- 52 Vol. 2, No. 1 February 2010

JIACD Continuing Education gal lesions. They were in good general health, region of the first molar. Four implants (Neo- with no systemic involvement as determined dent, Curitiba, Brazil) 4.5 X 9.0mm with internal during clinical examination by a veterinarian. Morse cone connections and sandblasted and acid-etched surfaces were placed 1.5mm subcre- Two weeks before the surgery, the dogs stally on one side of the mandible and the other received antiparasitic treatment, multivita- four implants were placed crestally on the contra mins and vaccines. Ultrasound prophylaxis lateral side. A total of 48 implants were placed was administered to remove supragingival cal- in the study. Distances between two adjacent culus and a solution of chlorhexidine glucon- implants were alternatively 2 or 3mm in both side ate 0.12% was applied on the teeth with gauze. of the mandible. Thus four groups were consti- tuted: (1)subcrestally with 2mm of interimplant The animals began fasting the night before distance (2 SCL); (2)subcrestally with 3mm of surgery. Anesthesia consisted of an intra- interimplant distance (3 SCL); (3)equicrestally muscular injection of a preanesthetic (acepro- with 2mm of interimplant distance (2 ECL); (4) mazine 0, 2% - 0, 05 mg/kg) followed by equicrestally with 3mm of interimplant distance intravenous administration of thiopental (1 (3 ECL). The distances between the implants ml/kg; 20 mg/kg thiopental diluted in 50 ml as well as the positions of implant placement saline). The animals were then moved to the were arbitrary determined through a coin toss. operating room and maintained on gas anes- thesia (1-2 % isoflurane/ O2 titrated to effect). After implant placement, metallic crowns were immediately installed with 3mm of distance In the first phase of the study, full-thickness between the contact point and the bone crest. The flaps were elevated bilaterally and the four mandib- soft tissues were sutured around the crowns for ular premolars of both hemi-arches of each animal non-submerged healing. The animals were main- were extracted. The teeth were sectioned in the tained on a soft diet for 14 days until the sutures buccolingual direction at the bifurcation, and the were removed. Healing was evaluated weekly and roots were individually extracted using a periotome plaque control was maintained by flushing the oral in order to not damage the bony walls. The flaps cavity with chlorhexidine gluconate. The remaining were repositioned and sutured with non-absorb- teeth were cleaned monthly with ultrasonic points. able 4-0 sutures. The animals received analgesic and anti-inflammatory injections and multivitamins. Eight weeks after restoration, the animals were anesthetized and then euthanized with an over- After a healing period of eight weeks, the dose of thiopental. The implants and the sur- dogs received 20,000 IU penicillin and strep- rounding tissues were retrieved and immediately tomycin (1,0 g/10 kg) the night before second stored in 10% buffered formalin. They were then surgery. This dose provided antibiotic coverage processed to obtain thin ground sections with for 4 days, thus another dose was given 4 days the Precise 1 Automated System (Assing, Rome, later to provide coverage for a total of 8 days. Italy).21 Firstly, the specimens were dehydrated in an ascending series of alcohol rinses and embed- After repeating the same sedation and anes- ded in a glycolmethacrylate resin (Technovit 7200, thesia protocol previously described, horizon- tal crestal incisions were bilaterally made from the distal region of the canine to the mesial The Journal of Implant & Advanced Clinical Dentistry 53

JIACD Continuing Education VLC, Kulzer, Wehrheim, Germany). After polym- Figure 1: In order to determine the osteocyte density, the erization, the blocks were sectioned longitudi- bone area was delineated (yellow line) and the osteocytes nally along the major axis of the implants with a were counted (green arrows) at 200x magni cation of the high-precision diamond disc at about 150 µm slides stained with acid fuchsin and toluidine blue. and ground down to about 30 µm. Three slides were obtained from the central part. The slides sity bone (woven bone), while unstained or were stained with acid fuchsin and toluidine blue. pale stained areas belonged to highly mineral- ized bone (lamellar bone) (figure 2). All images Histomorphometry was used to evaluate the were calibrated using the Pythagorean Theo- osteocyte index (Oi) that was calculated using rem for distance calibration, which reported the the equation Oi= N.Ot/ B.Ar, where N.Ot is the number of pixels between two selected points. number of osteocytes observed at 200X magni- fication on the section plane for an infinitely thin section, and B.Ar is the total area of the evalu- ated bone expressed in µm2 (or in square pix- els). The specimens were analyzed under a transmitted light microscope (Laborlux S, Leitz) that was connected to a high-resolution video camera (3CCD, JVC KY-F55B, JVCs, Yokohama, Japan) and interfaced to a monitor and PC (Intel Pentium III 1200 MMX, Intels, Santa Clara, CA, USA). This optical system was associ- ated with a digitizing pad (Matrix Vision GmbH, Oppenweiler, Germany) and controlled by a soft- ware package with image capturing capabilities (Image-Pro Plus 4.5, Media Cybernetics Inc., Immagini & Computer Snc, Milano, Italy). Woven and lamellar bone areas and cell number were analyzed using image managing software (Adobe Photoshop CS, version 8.0.1, Adobe Systems, Beaverton, OR) and image analysis software (Image J1.32j, Wayne Rasband, National Insti- tutes of Health, Bethesda, MD)(figure 1). Digital maps of histologic images at 200X magnifica- tion of the bone around loaded dental implants were reconstructed and evaluated. The acid fuchsin and toluidine blue staining facilitated the separation of woven and lamellar bone. Intensely red stained areas belonged to low mineral den- 54 Vol. 2, No. 1 February 2010

JIACD Continuing Education Figure 2: Digital map reconstruction of histologic images (magni cation x200) of the bone around loaded dental implants. The section was stained with toluidine blue and acid fuchsin. The white arrows indicate areas intensely red stained belonging to low mineral density bone (woven bone) while the black arrows referring to unstained or pale stained areas belonging to highly mineralized bone (lamellar bone). Asterisks (*) indicate marrow spaces. Double asterisks (**) indicate implant. Figure 3: (right) Di erences between osteocyte lacunae observed in woven bone (yellow arrows) and in lamellar bone (green arrows). The Journal of Implant & Advanced Clinical Dentistry 55

JIACD Continuing Education Intra-group Analysis mean standard deviation Inter-group Analysis *statistically significant Statistical analysis woven and lamellar bone were statistically sig- Comparisons of the differences in osteocyte den- nificant in each group individually, but not sity in woven and lamellar bone within the four between the experimental groups (table 1). groups separately were carried out using the non parametric Mann-Whitney U-test, for independent DISCUSSION samples. However, comparisons between the four groups were carried out using the non-parametric Woven bone forms rapidly during tissue growth, Kruskal-Wallis Test. Results were presented as following injury, and in response to certain anabolic means ± standard deviation (SD), and the con- stimuli, thus it is not found in the adult skeleton in fidence level of 95% was assumed for analysis. normal conditions.22 It has an important function helping to fill, quickly, bone defects. It provides ini- RESULTS tial bone continuity that guarantees some strength to a bone weakened by injury,22 although it can be Qualitative differences in osteocyte lacunae shape considered weaker when compared to the pre- and canalicular organization were observed among existent cortical bone in terms of bone density. the different tissue types (figure 3). Lacunae and osteocytes in woven bone appeared to be larger Several features of woven bone may cause than in pre-existing cortical bone. Osteocytes functional differences when compared to lamel- in lamellar bone varied from well organized lines lar bone. For example, the extracellular matrix when constituting an osteon unit to apparently ran- of woven bone is loosely organized and there is dom distributions in other specimens. However in considerable evidence that the composition of woven bone they always appeared spontaneously. the extracellular matrix in woven bone is differ- ent from that of lamellar bone.23 In the present The differences in osteocyte density between study, the shape and distribution of the lacu- 56 Vol. 2, No. 1 February 2010

JIACD Continuing Education nae appeared different in woven and lamellar cit is related to increased microdamage, but bone. While in the first, the osteocyte lacunae not necessarily to animal age. Mann et al5 also appeared larger and randomly distributed; in the found that the presence of fewer osteocytes in second they were smaller and appeared orga- aging specimens has been related to an impair- nized in their location, accompanying the con- ment of the ability to remove injured bone, centric lines that usually determine an osteon which determines a reduced level of remodel- unit. These qualitative differences could be ing activity. This remodeling activity, coordi- the result of the rapid rate of matrix synthesis nated between osteocytes, osteoblasts and in woven bone.17 Lastly, the osteocyte popula- osteoclasts, provides a basis for the adaptation tion in woven bone has been estimated to be of bone to external stimuli.1 Osteocytes have larger than that found in lamellar bone,24 how- a probable supervision of the biomechanical ever, data supporting this fact have been only regulation of bone mass and architecture, mod- rarely reported in the literature. The size of the ulating the activity of osteoblasts and osteo- osteocyte population may be especially impor- clasts by the production of chemical signals.8 tant in determining the biological properties of woven bone, as cell number certainly has an The results of the present study showed a important role in the growth and size of many highly significant statistical difference in the organs.25,26 Moreover, recent studies of lamel- osteocyte density of woven and lamellar peri- lar bone have implicated osteocytes as regu- implant bone. In some cases the values dif- lators of remodeling activity, formation rate fered by more than 100%. Similar results and tissue volume.27-29 Whether similar rela- have been reported by Hernandez et al.17 The tionships exist in woven bone is unknown. significance of the higher osteocyte density in woven peri-implant bone supports the hypoth- The present study evaluated the osteocyte esis that this bone needs to be most rapidly density in woven and lamellar bone around remodeled, and the concentration of relevant loaded implants, taking into consideration differ- signaling factors seemed to be increased in tis- ent interimplant distances and crestal or subcr- sues with high cell numbers.17 Furthermore it estal implant placements. It was thought that was suggested that a large cell density would quantifying their cellularity might be a way to bet- encourage the removal of tissue and pos- ter understand the regulation of their functions. sible replacement by tissue with a more typi- cal cell density,17 enhancing the bone strength Mechanosensors in bone are able to sense with superior levels of bone mineral density. a load-induced strain and to translate this infor- mation to cells at the bone surface5 and this is The loading conditions of the implants one theory to explain how osteocytes could be could also have an impact on the osteocyte directly involved in bone remodeling. Vashishth density. In a study done in our laboratory,20 et al30 showed an age-related decline in osteo- on retrieved human samples, it was found that cyte density that was correlated with microcrack the osteocyte density was higher in immedi- accumulation in human femoral mid-diaphyses. ately loaded implants when compared to sub- Qiu et al31 have confirmed that osteocyte defi- merged, unloaded implants. This study results The Journal of Implant & Advanced Clinical Dentistry

JIACD Continuing Education demonstrated that loading influenced positively The Academy of Dental Learning the osteocyte density, however it was also is an ADA CERP Recognized Pro- observed that the different conditions in terms vider. The Academy of Dental Learn- of interimplant distances and crestal or subcr- ing designates this activity for two estal implant placement did not affect the num- hours of continuing education credits. ber of osteocytes in woven or lamellar bone. ADA CERP is a service of the Ameri- CONCLUSION can Dental Association to assist den- tal professionals in identifying quality The woven peri-implant bone presented signifi- providers of continuing dental educa- cant higher number of osteocytes when com- tion. ADA CERP does not approve or pared to the lamellar bone, probably because endorse individual courses or instruc- of their different bone remodeling rates. How- tors, nor does it imply acceptance of ever the differences of crestal or subcrestal credit hours by boards of dentistry. implant placement and interimplant distances did not influence the number of osteocytes. Correspondence: Prof. Adriano Piattelli Professional Dental Education and Pro- Via F. Sciucchi 63 , 66100 CHIETI- Italy fessional Education Services Group Fax: 011-39-0871-3554076 are joint sponsors with The Academy E-mail: [email protected] of Dental Learning in providing this continuing dental education activity. Disclosure by the combination of confocal laser scanning microscopy Periodontol 2009;80:499-504. This work was partly supported by the Coordination for the and differential interference contrast microscopy. Bone 21. Piattelli A, Scarano A, Quaranta M. High-precision, cost- Development of Personnel in Higher Education (CAPES), 2001; 28:145–149. Brazil, and by the National Research Council (C.N.R.) and 11. Nicolella DP, Moravits DE, Ghe AM, Bonewald LF, effective system for producing thin sections of oral tissues the Ministry of Education, University, Research (M.I.U.R.), Lankford J. Osteocyte lacunae tissue strain in cortical containing dental implants. Biomaterials 1997; 18:577-579. Rome, Italy. bone. J Biomech 2006; 39:1735-1743. 22. Misch CE, Bidez MW, Sharawy M. A bioengineered implant References 12. Vezeridis PS, Semeins CM, Chen Q, Klein-Nulend J. for a predetermined bone cellular response to loading 1. Knothe Tate ML, Adamson JR, Tami AE, Bauer TW. The Osteocytes subjected to pulsating fluid flow regulate forces. A literature review and case report. J Periodontol osteoblast proliferation and differentiation. Biochem 2001; 72:1276-1286. osteocyte. Int J Biochem Cell Biol 2004; 36:1-8. Biophys Res Commun 2006; 348:1082–1088. 23. Gorski JP. Is all bone the same? Distinctive distributions 2. Mullender MG, van der Meer DD, Huiskes R, Lips P. 13. Tan SD, de Vries TJ, Kuijpers-Jagtman AM, Semeins CM, and properties of non- collagenous matrix proteins in Everts V, Klein-Nulend J. Osteocytes subjected to fluid lamellar vs. woven bone imply the existence of different Osteocyte density changes in aging and osteoporosis. flow inhibit osteoclast formation and bone resorption. underlying osteogenic mechanisms. Crit Rev Oral Biol Bone 1996; 18:103-113. Bone 2007; 41: 745–751. Med 1998; 9:201–223. 3. Roberts EW, Huja S, Roberts JA. Bone modelling: 14. Noble BS, Reeve J. Osteocyte function, osteocyte death 24. Buckwalter JA, Glimcher MJ, Cooper RR, Recker R. Bone biomechanics, molecular mechanisms, and clinical and bone fracture resistance. Molec Cell Endocrinol Biology Part I. J Bone Joint Surg 1995; 77A:1256– 1275. perspectives. Semin Orthod 2004; 10:123-161. 2000; 159:7-13. 25. Nijhout HF. The control of body size in insects. Dev Biol 4. Tan SD, Bakker AD, Semeins CM, Kuijpers-Jagtman AM, 15. Marotti G, Palumbo C. The mechanism of transduction 2003; 261:1– 9. Klein-Nulend J. Inhibition of osteocyte apoptosis by fluid of mechanical strains into biological signals at the bone 26. Conlon I, Raff M. Size control in animal development. Cell flow is mediated by nitric oxide. Biochem Biophys Res cellular level. Eur J Histochem 2007; 51: 15-19. 1999; 96:235–244. Commun 2008; 369:1150-1154. 16. Noble BS. The osteocyte lineage. Arch Biochem 27. Qiu S, Rao DS, Palnitkar S, Parfitt AM. Age and distance 5. Mann V, Huber C, Kogianni G, Jones D, Noble B. The Biophys 2008; 473:106-111. from the surface but not menopause reduce osteocyte influence of mechanical stimulation in osteocyte apoptosis 17. Hernandez CJ, Majeska RJ, Schaffler MB. Osteocyte density in human cancellous bone. Bone 2002; 31:313– and bone viability in human trabecular bone. J Muskuloskelet density in woven bone. Bone 2004; 35:1095-1099. 318. Neuronal Interact 2006; 6:408-417. 18. Novaes Jr AB, Barros RRM, Muglia VA, Borges GJ. 28. Qiu S, Rao DS, Palnitkar S, Parfitt AM. Relationships 6. Epstein S. Is cortical bone hip? What determines cortical Influence of interimplant distances and placement depth between osteocyte density and bone formation rate in properties? Bone 2007; 41:53-58. on papilla formation and crestal resorption: A clinical and human cancellous bone. Bone 2002; 31:709–711. 7. McReadie BR, Hollister SJ, Schaffler MB, Goldstein SA. radiographic study in dogs. J Oral Implantol 2009; 35: 29. Vashishth D, Gibson G, Kimura J, Schaffler MB, Fyhrie DP. Osteocyte lacuna size and shape in women with and without 18-27. Determination of bone volume by osteocyte population. osteoporotic fracture. J Biomech 2004; 37:563-572. 19. Barros RRM, Novaes Jr AB, Muglia VA, Iezzi G, Piattelli Anat Rec 2002; 267:292– 295. 8. Vatsa A, Breuls RG, Semeins CM, Salmon PL, Smit TH, A. Influence of interimplant distances and placement 30. Vashishth D, Verborgt O, Divine G, Schaffler MB, Fyhrie Klein-Nulend J. Osteocyte morphology in fibula and calvaria depth on peri-implant bone remodeling of adjacent and DP. Decline in osteocyte lacunar density in human cortical – Is there a role for mechanosensing? Bone 2008; immediately loaded Morse cone connection implants. A bone is associated with accumulation of microcracks with 43:452-458. histomorphometric study in dogs. 2009 (submitted). age. Bone 2000; 26:375– 380. 9. Parfitt AM. The cellular basis of bone turnover and bone 20. Barros RRM, Degidi M, Novaes Jr AB, Piattelli A, Shibli 31. Qiu S, Rao DS, Fyhrie DP, Palnitkar S, Parfitt AM. The loss: a rebuttal of the osteocytic resorption bone flow JA, Iezzi G. Osteocyte density in the peri-implant bone morphological association between microcracks and theory. Clin Orthop Relat Res 1977; 127:236–247. of immediately loaded and submerged dental implants. J osteocyte lacunae in human cortical bone. Bone 2005; 10. Kamioka H, Honjo T, Takano-Yamamoto T. A three- 37:10-15 dimensional distribution of osteocyte processes revealed Vol. 2, No. 1 February 2010

JIACD Continuing Education 1. True or False: Loading seems to play 6. Which bone undergoes more rapid a decisive role in bone formation and remodeling? bone mineral density. a. Lamellar bone a. True b. Woven bone b. False c. Both remodel at the same speed d. Neither bone is remodeled 2. The most abundant cells in mature bone are: 7. Lacunar density between woven and a. Fibroblasts lamellar bone can differ by as much as: b. Osteocytes a. 1-2% c. Epithelial cells b. 5-10% d. Multinucleated giant cells c. 10-25% d. 40-100% 3. Bone lacunae house which of the following? 8. True or False: Woven bone is typically a. Osteocyte cell bodies found in the adult skeleton under normal b. Polymorphonucleocytes conditions. c. Mast cells a. True d. Red blood cells b. False 4. True or False: Strain on bone results in 9. With advancing age, osteocyte density osteoblast recruitment and osteoclast and numbers have been shown to: inhibition. a. Increase a. True b. Decrease b. False c. Remain the same d. Oscillate 5. In response to a need of quick bone formation, which bone is formed? 10. Osteocyte density in woven a. Lamellar bone peri-implant bone is: b. Woven bone a. Higher c. Cortical bone b. Lower d. Demineralized bone c. The same as lamellar bone d. No osteocytes exist in peri-implant bone CLICK HERE TO TAKE THE QUIZ The Journal of Implant & Advanced Clinical Dentistry

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Fugazzotto

Decision Making: Fugazzotto The Furcated Molar Dr. Paul Fugazzotto1, DDS Abstract The problem of the periodontally involved ing from “maintenance” to resective therapy furcation is discussed, and various treat- to extraction with concomitant implant place- ment options are assessed. Clinically ment and/or regeneration are reviewed. Deci- applicable definitions of furcation involvements sion trees are presented to help ensure are offered for use. Treatment options rang- appropriate treatment modality selection. KEY WORDS: Molars, furcation, diagnosis, treatment protocols, bone grafting, dental implants 1. Private practice limited to Periodontics and Dental Implants, Milton, Massachusetts, USA The Journal of Implant & Advanced Clinical Dentistry 63

Fugazzotto INTRODUCTION ments were lost at a rate of 30.7% and 24.2% respectively, a rate which was higher than the Our understanding of treatment options when incidence of non-furcated tooth loss. McFall3, faced with a furcated molar has evolved dramati- reporting on tooth loss in one hundred treated cally over the last few decades. Early attempts patients with periodontal disease maintained for at “maintenance” of involved furcations centered fifteen years or longer following active therapy, around repeated debridement of a closed or sur- noted loss of maxillary and mandibular teeth gical nature or tunneling to ostensibly provide with furcation involvements at rates of 22.3% access for professional and patient plaque con- and 14.7%, respectively. Similar findings have trol efforts. However, it soon became evident that been consistently reported in the literature.4-6 such therapies were nothing more than means by which to slow down progression of the dis- A study by Fleisher et al7 underscores the ease process in periodontally involved furcations. extreme difficulty in performing total debride- ment of a periodontally involved furcation. Fifty Furcation involvements represent a unique molars were treated through closed curet- and challenging area of potential increased tage or open flap debridement, and were then plaque accumulation and hence, rapid periodon- extracted and stained to assess the efficacy of tal breakdown. A sampling of literature under- debridement. Only 68% of the tooth surfaces scores the inadequacy of most therapies in the facing the involved furcations were calculus “maintenance” of periodontal health around free. Although the utilization of microscopy and invaded furcations, without elimination of the newer instrumentation greatly improves the cli- aforementioned furcation involvement. Becker nician’s ability to thoroughly debride involved et al1, in a longitudinal study of patients who furcations, such debridement does not elimi- refused active periodontal therapy but remained nate the furcation involvement itself, which rep- under continued maintenance care, reported an resents a harbor for plaque. While debridement overall rate of tooth loss of 9.8% in the mandible may “slow down” the rate of progression of and 11.4% in the maxilla. Mandibular furcated periodontal disease in the involved furcation, teeth were lost at a rate of 22.5% while maxil- it is not a desired treatment endpoint in most lary furcated teeth were lost at a rate of 17%. clinical situations. The furcation must be elimi- This pattern of teeth with furcation involvements nated, thus providing the patient with a milieu being less amenable to “maintenance care” than amenable to appropriate plaque control efforts. their single rooted counterparts is confirmed by Goldman et al2 who assessed tooth loss in 211 In the 1960’s and 1970’s efforts were made patients treated in a private periodontal prac- to develop techniques to eliminate furcation tice through root planing, curettage, and open involvements. Such approaches ranged from flap debridement, and maintained for fifteen to odontoplasty to root amputation to tooth sec- thirty years on a consistent recall schedule. Fur- tioning, with or without extraction of a sectioned cation involvements were not eliminated. The root. Furcation defects are described as a func- overall rate of tooth loss was 13.4%. Maxil- tion of the extent of periodontal destruction in lary and mandibular teeth with furcation involve- both the horizontal and vertical dimensions. 64 Vol. 2, No. 1 February 2010

Fugazzotto Figure 1: The patient presents with a Class I buccal Figure 2: Following appropriate odontoplasty, the furcation involvement and a Class II cemento enamel cemento enamel projection has been removed and projection. the Class I furcation involvement has been eliminated. Mucoperiosteal aps will now be sutured at osseous crest. Figure 3: Failure to treat a Class III cemento enamel The end result of treatment will be an area which is easily projection in a timely and e ective manner has resulted in maintained by the patient. the development of Class III furcation involvement and a hopeless prognosis for a mandibular rst molar. Horizontal furcation involvements: Class I: The entrance into the fur- cation extends less than half of the horizontal dimension of the tooth. Class II: Entrance into the furcation extends greater that half of the horizon- tal dimension of the tooth, but less than the full horizontal dimension of the tooth. Class III: Entrance into the furca- tion extends along the complete horizon- tal dimension of the tooth, connecting both the buccal and lingual furcation entrances. The Journal of Implant & Advanced Clinical Dentistry 65

Fugazzotto Vertical furcation involvements: along manner. The result of treatment is elimination of A. Loss of attachment apparatus com- both deeper pocket depths and Class I furcation less than 25% of the vertical tooth. involvements. When such therapy has been per- ponent of the furcation of the formed, the definition of success is no entrance of the probe into the furcation of the tooth, and B. Loss of attachment apparatus along more no probing depths in excess of 3mm around the than 25% but less than 50% of the verti- tooth. Coincident to the ondontoplasty is the cal component of the furcation of the tooth. elimination of all cemento enamel projections, thus enhancing the ability to form an appropri- C. Loss of attachment appara- ate attachment apparatus to protect the furcal tus along more than 50% of the verti- entrance. Such ondontoplasty is highly predict- cal component of the furcation of the tooth. able and may be carried out without a prosthetic commitment. If early furcation involvements are While the vertical component of furcation not eliminated through ondontoplasty, continued involvement has significant ramifications in the periodontal breakdown and attachment loss in the treatment of Class II furcations, it plays no role furcation area will occur, resulting in an untreat- in the treatment of Class I furcations unless this able situation and eventual tooth loss (Figure 3). involvement extends to such a degree that it either renders attainment of appropriate osse- Aggressive treatment of Class I furca- ous morphologies impossible, or reaches the api- tion involvements is conservative therapy. For ces of the tooth in question. In such situations, example, if a twenty-five year old patient pres- molar extraction and implant placement must ents with excellent home care, minimal prob- be effected, as will be subsequently discussed. ing depths, and a Class III cemento enamel projection in the buccal furcation area of a Class I furcation involvements can always be lower first molar as evidenced by examina- eliminated through ondontoplasty. If the bone tion following retraction of unattached soft tis- loss in the area of the Class I furcation involve- sues in this area, the clinician must make a ment has a vertical component which extends to decision between two treatment approaches: such an extent that positive architecture may not be developed, the problems in this region can- I. The patient could be placed on a strict main- not be resolved in such a manner. Such develop- tenance schedule, and the clinician could ments are rare with Class I furcation involvements. attempt to “maintain” the furcation in question The roof of the furcation is recontoured to elimi- through repeated professional prophylaxis vis- nate the cul-de-sac which traps plaque and the its. This approach may appear to offer advan- newly established tooth contours are carried onto tages to the patient. However, the net result the radicular surfaces of the tooth to create a con- of such a “treatment” approach will be pro- tinuous smooth morphology conducive to patient gression of periodontal disease in the furca- plaque control efforts (Figures 1 and 2). Osse- tion area, periodontal attachment loss, and/ ous resection with apically positioned flaps is or development of a furcation involvement. performed at the same time in the conventional 66 Vol. 2, No. 1 February 2010

Fugazzotto Table 1: Root Resection Failures over 10 or More Years Name Year Length of Cases % Failures Carnevale8 1991 3-11 years 488 5.7% Basten9 1996 2-23 years 49 8% Carnevale10 1998 10 years 175 7% Ricchetti11 1989 1-10 years 408 6% Ricchetti12 1997 10-18 years 169 9.6% II. flap may be reflected, and ondontoplasty per- purview of this chapter to discuss regenerative formed to eliminate the cemento enamel projec- options when faced with Class II furcation involve- tion and any early furcation involvements which ments. The applicability of root resective tech- have developed. The result of such a treatment niques in today’s environment is discussed below. result will be elimination of anatomical factors contributing to periodontal breakdown in the Root resection furcation area, the development of an appropri- Root resection has proven to be a predictable ate attachment apparatus, and establishment procedure with long lasting results. Multiple cli- of appropriate hard and soft tissue morpholo- nicians8-12 demonstrated long-term success with gies which are conducive to home care efforts. root resection (Table 1) that is comparable to other furcation treatments and dental implants. Timely intervention is crucial when faced with Root resection can also prove to be a cost-effec- Class I furcation involvements and/or Class III tive procedure when weighed against the alter- cemento enamel projections, so as to preserve native of implant insertion in situations requiring the alveolar bone and attachment apparatus on extensive bone augmentation or sinus lift graft- the tooth, and eliminate the need for more aggres- ing.13 Root resection can be as effective as sive therapies at a later date. Class II furca- periodontal treatment of single rooted teeth in tion involvements may not be eliminated through patients of equal periodontal susceptibility14 and ondontoplasty, as such tooth recontouring would more effective in certain upper molars than guided result in a tooth morphology which was deeply tissue regeneration.15 Although root resection is notched and not conducive to plaque control a technique-sensitive procedure, if considered for efforts. If a tooth with a Class II furcation involve- appropriate teeth in specific cases it can remain ment is to be maintained, either resective tech- part of today’s periodontal clinical armamentarium. niques involving root resection or tooth sectioning, or regenerative techniques employing mem- Obtaining acceptable long-term results with branes, graft materials, growth factors or other root resection demands attention to detail in the substances must be employed. It is not within the diagnostic process. There are nine basic cat- The Journal of Implant & Advanced Clinical Dentistry 67

Fugazzotto Table 2: Nine Basic Categories of Table 3: Modifying Diagn Diagnostic Factors that Modify the Furcation Classi cation and Treatment Bone Root Endodontic Planning for furcation Involved Teeth Loss Anatomy Status Interproximal Root trunk Size of ll bone height length Bone Loss Occlusal Status Root Anatomy Residual Ridge Interradicular Shape of Quality of bone loss dome ll Endodontic Status Patient Status surface Restorative Status Importance of the Tooth Entrance architecture Periodontal Status Root egories of diagnostic factors that can modify curvature the clinical classification of a furcation involve- ment and affect furcation treatment planning and Root width the decision to resect, regenerate, or extract a tooth with a compromised furcation (Table 2). Root length Predictable success with root resection Crown-root depends upon matching the appropriate treat- ratio ment alternative with a tooth conducive to suc- cessful treatment outcomes in deeper Class II Root (horizontal probing depths of 3-5 mm) or Class proximity III furcation involvements (horizontal probing depths greater than 5 mm).16 The key to choos- tive for root resection whereas others are positive ing appropriate molars for sectioning is under- for regeneration, repair, or implant replacement. standing the implications of the diagnostic factors To ensure success with root resection a fur- which modify the clinical classification of furca- cated tooth must be chosen which possesses tion involvement, and the diagnostic process the greatest number of modifying diagnostic fac- entailed in treatment planning. The nine basic tors that are positive and conducive to predict- categories of diagnostic factors which can mod- able root resection, than for other treatment ify the clinical classification of a furcation involve- alternatives. Utilization of such a diagnostic pro- ment break out into thirty modifying diagnostic cess ensures furcation treatment will be pursued factors. Each has positive or negative variables which will yield a predictable long-term outcome which determine the most appropriate treat- that is the most cost effective for the patient. ment choice for an involved furcation (Table 3). Root resection should be limited to deeper Certain modifying diagnostic factors are posi- Class II and Class III furcation involvements with modifying diagnostic factors which positively 68 Vol. 2, No. 1 February 2010

Fugazzotto nostic Factors Affecting Treatment Choices in Furcation Involved Teeth Occlusal Periodontal Patient Restorative Residual Importance Status Status Status Status Ridge of Tooth Mobility Keratinized Compliance Post + core Residual Key tooth tissue height volume Tooth Biologic Tobacco Remaining Residual Moderate position width use volume width key tooth impingement Interocclusal Resistance Ferrule Augmentation Inconsequential space to disease required tooth Orthodontics Esthetics Span of prosthesis influence the clinical outcome. While clinical situ- upon the positive diagnostic factors for resec- ations with deep Class II or Class III furcation tion, is the key to success when pursuing root involvements may be encountered that appear removal. An in depth discussion of these factors amenable to resection, negative modifying diag- can be found in Implant and Regenerative Ther- nostic factors may contraindicate root resection. apy in Dentistry: A Guide to Decision Making.19 Understanding how these modifying diagnostic factors influence treatment choices in deep Class Guided tissue regeneration became a popu- II and Class III involvements leads to better treat- lar means by which to attempt to rebuild dam- ment choices and greater success, but requires aged alveolar bone and attachment apparatus scrupulous attention to detail. Some clinical situ- in periodontally involved furcations in the mid ations involving deeper furcation involvements 1980’s. However, efforts at such therapy are best treated by repair, some by regeneration, were plagued by incomplete diagnostic cri- and some by extraction and replacement.15,17,18 teria, and limitations in technical executions. Choosing the appropriate clinical situation, based The advent of predictable implant therapy has significantly altered treatment approaches The Journal of Implant & Advanced Clinical Dentistry 69

Fugazzotto when faced with periodontally involved furcations. the past twelve years, various treatment While most practitioners would agree that it is approaches have been advocated, including: foolhardy to attempt to perform extensive regener- ative therapy around a tooth which demonstrates I. Tooth extraction, defect debridement, and severe bone loss and a deep periodontal furca- implant placement approximately 12 months tion, disagreements abound regarding when to following resolution of any “inflammatory “draw the line” and consider a tooth hopeless and lesions in” the bone: While agreeing with the slated for extraction and implant placement, with original protocols concerning implant place- or without concomitant regenerative therapy. This ment in “infected sites”, this approach sig- diagnostic decision is the greatest challenge fac- nificantly protracts the course of therapy. In ing clinicians today when contemplating the fate of addition, the degree of alveolar ridge resorp- a tooth which demonstrates furcation involvement. tion post extraction is unpredictable, often resulting in less than ideal alveolar bone at the Theoretically, a furcated tooth may be receptor site for eventual implant placement. treated in one of the following manners: II. Tooth extraction and defect debridement, fol- Maintenance through repeated debridement. lowed by immediate placement of two implants in Odontoplasty. the root extraction sockets: This approach helps Root amputation/tooth hemi section. to avoid post extraction bone resorption, and Tooth extraction, concomitant regenerative permits the clinician to affect implant placement therapy, followed by implant placement in in a fresh extraction socket of sufficient dimen- second stage surgery. sion. However, the final prosthetic result of two Tooth extraction, implant placement and “bicuspids” is less than ideal, as the concept of concomitant regenerative therapy in “bicuspidization” of a mandibular molar present- one surgical visit. ing with a deep furcation involvement was devel- If implants are to be placed at the time of oped for utilization during resective periodontal maxillary or mandibular molar tooth extrac- therapy and periodontal prosthetic reconstruction tion, the clinician must be able to insert such is inherently flawed. The result of sectioning a implants in ideal restorative positions. When mandibular molar is not two bicuspids. If the ratio such positioning is not attainable, teeth should be of the mesio distal dimension to the bucco lingual extracted, appropriate augmentation performed, dimension of the created “interproximal space” is and implants placed in a second surgical visit. examined, it does not approach the ratio of the space between two mandibular bicuspids, unless Implant placement in mandibular the roots of the mandibular molar are more dra- molar sites matically flared than normal, or orthodontic ther- Replacement of hopeless mandibular molars apy is employed to separate the sectioned roots. with implant restorations has undergone sig- The result is an interproximal space which heals nificant evolution since the introduction of osseointegrated implants in the 1980’s. Over 70 Vol. 2, No. 1 February 2010

Fugazzotto Figure 4: A Class II buccal furcation involvement is present Figure 5: A lingual view demonstrates no periodontal on a mandibular rst molar. involvement of the lingual furcation of the rst molar. Figure 6: A mandibular rst molar has been sectioned. This Figure 7: Following extraction of the mesial root of “bicuspidization” does not result in 2 bicuspids. the mandibular rst molar it is evident that a ration of the buccolingual to mesiodistal dimensions of the with a non keratinized concave soft tissue col interradicular bone between the sectioned roots of the form, posing a significant challenge to home care mandibular molar would not have been equal to the same efforts (Figures 4-7). Although the ossseointegra- ratio between the two adjacent bicuspids. Retention of tive bond has been shown to be less susceptible both roots of the sectioned mandibular molar would have to extension of an inflammatory lesion from the gin- resulted in an area of di cult maintenance for the patient. gival sulcus than its natural tooth counterpart, it is not impervious. Therefore, a treatment approach The Journal of Implant & Advanced Clinical Dentistry 71

Fugazzotto which results in a potential area for greater utilizing this treatment approach, an implant of plaque accumulation, and difficulty in plaque appropriate dimension must be ideally positioned control efforts, should not be considered ideal. in the area of the interradicular bone. Assuming that the ideal implant position of a fixture of the III. Extraction of a hopeless mandibular molar, desired dimensions and morphology has been defect debridement, and placement of an implant attained, failure to perform concomitant regen- in one of the root sockets, followed by restora- erative therapy represents a potential treatment tion with a molar sized crown: The concern of compromise. While there is no doubt that an two implants being placed closely together in the implant placed in a mandibular molar extraction root extraction sockets is addressed. However, socket without concomitant therapy will attain this treatment appropriately results in a mesial osseointegration, significant socket remodeling cantilever of the implant restoration, and an area will occur, resulting in loss of bucco lingual socket of potential plaque accumulation (Figure 8). dimension and crestal height, to varying degrees. IV. Tooth extraction, defect debridement, and VII. Tooth extraction followed by ideal implant placement of particulate graft material in the positioning and concomitant regenerative ther- extraction socket defects, followed by second apy: This treatment approach should not be stage implant placement: While this approach employed unless an implant of the desired has traditionally offered an incremental improve- dimension and morphology can be placed in ment in treatment outcomes over Option I, an ideal restorative position. When such place- placement of particulate graft materials with- ment may be effected, the use of concomitant out the appropriate covering membrane, while regenerative therapy results in preservation of all effecting somewhat greater socket fill than remaining alveolar bone in the extraction socket tooth extraction with no graft material, results area, re-establishment of prepathologic alveo- in a final alveolar bone quantity and morphol- lar ridge morphology, and bone buccal and lin- ogy which is non ideal and unpredictable. gual to the implant of sufficient thickness to withstand functional forces over time. The need V. Tooth extraction followed by particulate graft for a second surgical session is eliminated. placement and utilization of an appropriate cov- ering membrane, with second stage implant Implant placement at the time of mandibu- placement: The desired alveolar ridge morphol- lar molar extraction should never be attempted ogy may be predictably rebuilt, in anticipation of if there is any doubt about the ability to place implant placement, idealizing implant position, and an ideal dimension implant in the appropri- allowing use of the desired implant morphology. ate restorative position and attain primary sta- bility. In such a situation it is better to first VI. Tooth extraction and immediate implant place- perform regenerative therapy at the time of ment in an ideal restorative position, without the tooth removal, and place the implant in a sub- use of concomitant regenerative materials: When sequent surgical session (Figures 9-11). All mandibular multi-rooted teeth should be 72 Vol. 2, No. 1 February 2010

Fugazzotto Figure 8: An implant has been placed in the mesial Figure 9: The mandibular rst molar is hopeless due to root socket of a mandibular rst molar by a previous a presence of a vertical fracture. At the time treatment practitioner. The restoration recreated a “furcation” in the was performed techniques were not available to ideally area, representing a hindrance to proper patient plaque position an implant of desired dimension at the time of control. mandibular molar extraction. Figure 10: Following tooth sectioning and extraction, Figure 11: An implant with a 4.8mm wide body and a defect debridement and utilization of appropriate 6.5mm wide restorative platform has been restored with an regenerative materials, extensive bone regeneration abutment and crown, and has been in function for over 7 is noted in the area of the rst molar. An implant of years. the desired dimension may now be placed in an ideal prosthetic position. The Journal of Implant & Advanced Clinical Dentistry 73

Fugazzotto hemisected (or trisected in the rare cases Maxillary molar replacement with implant of three rooted mandibular molars) prior restored prosthetics: to removal. A piezosurgical approach is A variety of treatment options present them- utilized, in conjunction with specifically selves at the time of tooth extraction in the designed periotomes, to effect atraumatic posterior maxilla, including the following: tooth extraction. If such therapy is performed appropriately, the net result is an extrac- I. Augmentation of the extraction socket defect tion socket whose alveolar morphology has utilizing particulate material and a secured been no further compromised through the covering membrane may be mandated when act of tooth removal. In situations where faced with one or more of the following: high speed rotary instrumentation must be utilized to help retrieve fractured root por- A. Anticipated implant placement and tions, the site is deemed no longer ame- restoration within the patient’s esthetic nable to immediate implant placement due zone, in the face of a severely com- to the excessive trauma having been placed promised buccal alveolar ridge. on the alveolar bone in the area. Regen- erative therapy is performed employing B. Anticipated implant placement in appropriate graft materials and covering mem- an extraction socket defect with inad- branes, and the implant is placed in a sec- equate residual interradicular bone for ond surgical visit. Such instances are rare. fixation of the implant in the desired restorative position, due to root mor- Following tooth extraction, the defect phology or pathologic bone destruction. is thoroughly debrided, and the extent and morphology of alveolar bone destruction C. Anticipated implant placement in a residual are assessed. The presence or absence of extraction socket that is too wide to stabilize periapical and/or periodontal inflammatory the implant in the desired restorative position. lesions prior to defect debridement plays no role in the determination of whether or not II. Implant placement in a residual extraction to immediately insert an implant. Rather, it socket defect followed by utilization of appro- is the morphology and quantity of residual priate particulate materials and covering mem- alveolar bone in the extraction socket area branes to facilitate regeneration of alveolar which determines whether or not an implant bone in the residual extraction socket defect will be placed at the time of tooth extraction. surrounding an appropriately sized implant. Although ideal implant positioning may III. Implant placement in the extraction be attained in the vast majority of situa- socket following implosion of a core of tions at the time of extraction of a mandibu- autogenous bone apical to the extraction lar molar, it is imperative that the surgical site socket. Particulate materials and a covering be assessed after tooth removal and defect membrane are then placed to facilitate regen- debridement have been accomplished. 74 Vol. 2, No. 1 February 2010

Fugazzotto eration of alveolar bone in the residual extrac- lowing such a determination, an assessment tion socket defect surrounding the implant. must be made of whether or not an implant of the desired dimensions may be placed in an IV. Lateral sinus augmentation therapy and aug- ideal restorative position either at the time of mentation of the residual extraction socket defect tooth removal, or in an edentulous site with or utilizing particulate material and membrane. without concomitant regenerative therapy. If such a determination is in the negative, regen- V. Lateral sinus augmentation therapy with erative treatments must be undertaken prior simultaneous implant placement and regen- to considering implant placement. Neither the eration of alveolar bone in the residual extrac- patient not the clinician benefits from a mal- tion socket defect surrounding the implant, positioned or inappropriately sized implant. through the use of particulate material and the appropriately secured covering membranes. Augmentation and implant placement at the time of maxillary molar extraction: It is imperative that the definition of suc- If either the root morphology of the maxillary molar cess following augmentation of extraction socket to be replaced, or the extent of periodontal alve- defects be established prior to material and olar bone destruction around the hopeless tooth treatment selection. A comprehensive defini- preclude implant appropriate implant placement tion of success following such therapy must at the time of tooth extraction, an augmentation include both regeneration of bone within the should be carried out upon tooth removal, and the extraction socket, and regeneration of prepatho- implant placed in a subsequent surgical session. logic alveolar ridge morphology, including buc- The tooth is sectioned, and each root is removed cal and palatal/lingual alveolar bone line angles, utilizing piezosurgery and specifically designed so as to ensure adequate thickness of bone on periotomes, with care being taken to preserve the buccal and palatal/lingual aspects of the the interradicular bone (Figure 12). Upon defect implant, and appropriate hard tissue support debridement, a trephine is chosen with sufficient of the soft tissue drape and esthetics around diameter to encompass the interradicular bone the restored implant. Such conceptualization, (Figure 13). The trephine is placed over the inter- while more technically rigorous and demanding radicular bone and an osteotomy is prepared to of specific materials and treatment protocols, at within 1mm of the sinus floor (Figures 14, 15). least diminishes and usually eliminates the need If the sinus membrane appears to invaginates for secondary soft tissue grafting procedures. around the extraction socket radiographically, thus presenting a potential compromise should any Placement of implants in maxillary poste- apical preparation of the extraction socket be car- rior areas is highly patient and site specific. ried out with a trephine, an osteotome is applied Prior to initiating such therapy, whether at the to the interradicular bone prior to trephine utiliza- time of tooth removal or in edentulous areas, tion, and gently malleted. In such situations, if the a determination must be made of the minimum interradicular bone implodes upon such gentle implant dimensions necessary in the context of the patient’s individualized treatment plan. Fol- The Journal of Implant & Advanced Clinical Dentistry 75

Fugazzotto Figure 12: A maxillary molar has been trisected, and the Figure 13: A trephine is chosen of su cient diameter to roots have been extracted individually with care being encompass the interradicular bone. taken to preserve the residual interradicular bone. Figure 14: The trephine is placed over the interradicular Figure 15: An osteotomy is prepared to within one bone. millimeter of the sinus oor. malleting, no trephine use is necessary. However, than the height of the interradicular bone. Such should the interradicular bone prove immobile in care is taken so as to both help preserve the the face of osteotome malleting without trephine intact nature of the displaced sinus membrane utilization, the trephine is employed as previously and to keep the core within the borders of the described, and an osteotome is subsequently alveolar bone, thus ensuring it does not become utilized to displace the prepared bone core api- “free-floating” in the sinus (Figure 18). Particu- cally, thus lifting the sinus membrane in the area lar materials are placed, the appropriate covering of the interradicular bone (Figures 16-18). A membrane is secured with fixation tacks, and flap core is always imploded to a depth 1mm less designs are utilized to ensure passive primary clo- than the depth of the trephine cut. If no trephine sure, as described in pervious publications (Fig- had been utilized, the core is imploded 1mm less ure 19).20-22 Following bone regeneration more 76 Vol. 2, No. 1 February 2010

Fugazzotto Figure 16: The detached bone core is imploded with an Figure 17: A view from within the sinus demonstrates the osteotome. imploded core and lifted sinus membrane. Figure 18: The core has been imploded and the sinus Figure 19: Following placement of appropriate grafting membrane has been displaced. materials a covering membrane is secured with xation tacks. Membrane selection is a result of previously Figure 20: Following healing, a localized sinus discussed criteria. augmentation procedure has been performed in the desired implant position. than adequate bone will be present in the previ- ous interradicular area for appropriate implant placement (Figure 20). Clinical examples of this treatment approach are evident in Figures 21-27. Implant placement at the time of maxillary molar extraction: If adequate interradicular bone is pres- ent to effect placement of an implant of the desired dimensions in an ideal restorative posi- The Journal of Implant & Advanced Clinical Dentistry 77

Fugazzotto Figure 21: A patient presents with a hopeless prognosis Figure 22: Six months after core implosion and utilization for both maxillary molars and the maxillary second of appropriate regenerative materials extensive bone bicuspid. Inadequate bone is present for appropriate regeneration is evident radiographically, providing more implant stabilization in an ideal restorative position. than adequate bone for ideal implant placement. Figure 23: A patient presents with a buccal stula and Figure 24: Following tooth extraction, implosion of a hopeless prognosis for a maxillary rst molar. The the interradicular bone, and utilization of appropriate remaining bone protecting the mesial furcation of the regenerative materials, a six month radiograph second molar is at risk. demonstrates bone regeneration, and preservation of the bone protecting the entrance to the mesial furcation of the second molar. Figure 25: A wide platform implant is placed in the Figure 26: A radiograph taken eight plus years in function imploded and regenerated bone. demonstrates stable peri-implant crestal bone. 78 Vol. 2, No. 1 February 2010

Fugazzotto Figure 27: A clinical view of the restored implant. the inserted implant. Either a parallel walled wide platform implant or a tapered implant with a 4.8 tion following tooth sectioning and gentle mm wide “apex” and a 6.5 mm wide platform is extraction of a maxillary molar, both the interra- inserted, depending upon the final morphology dicular bone morphology and the need or lack of the manipulated interradicular bone. If utiliza- of need for additional bone height must now tion of a tapered implant would result in loss of be assessed. Following such an assessment, significant portions of the interradicular bone as it therapy will proceed in one of four manners: broadens in its most crestal third, a parallel walled implant is placed. The advantages to tapered If no additional alveolar bone height is end implant use are both greater obliteration of required: the residual extraction socket defect surround- I. When a wide interradicular septum is pres- ing the implant, and an increased implant surface ent, with wide being defined as a septum which area available for osseointegration. If particulate will completely cover the rough surface of the materials and the appropriate secured covering implant following its manipulation, 2.2 mm guide membrane are placed around the implant, the drill is utilized to prepare the initial osteotomy to flaps are manipulated as previously described its final depth. Tapered osteotomes, of sequen- to ensure passive primary closure throughout tial diameters which correspond to the implant the course of regeneration. However, if the use drilling sequence are utilized to spread the inter- of a tapered implant has either obliterated the radicular bone. While the most crestal aspect of residual extraction socket defect, or resulted in the interradicular bone is usually split or lost, this a horizontal defect dimension of 3mm or less, no is of no consequence. The interradicular bone regenerative materials are employed. The ability manipulation creates an osteotomy of sufficient to eliminate the need for regenerative materials dimension to accept the planned implant, and and thus place the implant in a one stage man- compacts the bone laterally which helps stabilize ner, is also dependent upon having extracted the tooth as atraumatically as possible, and leaving the alveolar walls of the extraction socket intact. II. When a narrow interradicular bony septum is evident following tooth sectioning and extraction, with narrow being defined as a septum which will not encompass the rough surface of the implant body following its manipulation, different site preparation protocols and implant selection are employed. Piezo surgery is utilized to notch the most crestal aspect of the interradicular bone, providing a set point for use of a tapered osteo- tome. A tapered osteotome is employed to the The Journal of Implant & Advanced Clinical Dentistry 79

Fugazzotto Figure 28: Hopeless maxillary right rst and second Figure 29: A 2.2mm wide osteotome is utilized to spread bicuspids and rst molar have been extracted. Note the the interradicular bone. intact interradicular bone in the rst molar area. Figure 30: A view of the interradicular bone in the rst Figure 29: A 2.2mm wide osteotome is utilized to spread molar area following use of the 2.2mm wide osteotome. the interradicular bone. Note the 3.5mm wide osteotomy in the second bicuspid site. otomy depth. The osteotomy is only widened to 3.5mm, not 4.2 mm as would be necessary final depth of the planned osteotomy. Sequen- for placement of a parallel walled or tapered tially widening tapered osteotomes, whose diam- end conventional wide platform implant but an eters correspond to the drilling sequence of the implant is utilized which has a 4.1 mm wide implant system to be utilized, spread and shape the residual interradicular bone to the final oste- 80 Vol. 2, No. 1 February 2010

Fugazzotto Figure 31: The interradicular bone osteotomy is expanded Figure 32: A tapered end implant with a 4.1mm base and to 3.5mm a 6.5mm restorative platform is brought to the mouth on a hand piece carrier. Figure 33: Implant insertion begins utilizing a hand piece Figure 34: The implant is inserted to the appropriate carrier, at 30 RPMs. depth. “apex” and a 6.5 mm wide platform (Figure 28), loss of its integrity and its stabilizing function. affording the opportunity to place the implant Appropriate regenerative materials and cover- into the manipulated interradicular bone and ing membranes are placed and flap designs attain primary stability without unduly widen- are utilized, as previously described. This ing this interradicular bone, which could cause approach is demonstrated in Figures 29-49. The Journal of Implant & Advanced Clinical Dentistry 81

Fugazzotto Figure 35: A buccal view demonstrates the compromised Figure 36: Osseous coagulum is packed in the residual buccal alveolar ridge around the implant. Note the ideal extraction socket defect surrounding the implant. positioning of the implant. Figure 37: A view of the lled extraction socket defect. An Figure 38: A buccal view of the completed restorations of appropriate membrane will now be placed and secured the implants in the rst molar and rst and second bicuspid with tacks. positions. If additional bone height is required in the proceeds in one of two manners, depending interradicular area: upon the morphology of the interradicular bone: When inadequate alveolar bone height is pres- ent crestal to the floor of the sinus for placement I. If a wide interradicular septum is present: of an implant of the desired dimensions, therapy A 2.2 mm wide trephine and flat-ended 82 Vol. 2, No. 1 February 2010

Fugazzotto Figure 39: An occlusal view of the completed restorations. Figure 40: A radiograph taken six months post therapy Note the normal sized occlusal tables of the implant demonstrates complete bone ll around the implants. restorations. Figure 41: A radiograph taken more than six years after Figure 42: A patient presents with a hopeless prognosis restoration demonstrates stable crestal bone around the for a fractured maxillary right second bicuspid and rst implants. These implants would not be splinted today. molar, and a missing maxillary right second molar. osteotome are utilized to implode the interra- osteotome is brought to the desired depth, with dicular bone. The osteotomy site is widened care once again being taken to ensure that the with sequentially sized osteotomes, whose most crestal millimeter of the imploded inter- diameters correspond to the drilling sequence radicular core still rests within the apical con- for the implant system to be utilized. Each fines of the residual alveolar bone. Once the The Journal of Implant & Advanced Clinical Dentistry 83

Fugazzotto Figure 43: A radiograph taken six months after tooth Figure 44: An occlusal view of the implant restorations extraction, implosion of a core with simultaneous implant after over four years in function. placement in the second molar position, manipulation of the interradicular bone with simultaneous implant placement in the rst molar position, and immediate implant placement in the second bicuspid position, demonstrates excellent bone healing around the implants. Figure 45: A buccal view of the implant restorations after Figure 46: An implant has been placed after both over four years in function. manipulation and implosion of the interradicular bone, and attainment of additional alveolar height. desired osteotomy site has been prepared, either a straight walled implant with a 6.5 ing upon the final morphology of the manipu- mm wide platform or a tapered end implant lated alveolar bone, as previously discussed. with a 4.8 mm wide “apex” and a 6.5 mm wide restorative platform is placed, depend- II. If a narrow interradicular septum is present: Sequentially widening tapered end osteo- 84 Vol. 2, No. 1 February 2010

Fugazzotto Figure 47: A patient presents with an intrafurcal fracture Figure 48: The imploded bone core is evident at the apex on a maxillary rst molar. The tooth is trisected and of the implant. extracted, the interradicular bone is manipulated and imploded, and a tapered end implant with a 4.8mm base tomes are utilized to both implode the interra- and a 6.5mm restorative platform is placed. Appropriate dicular bone coronal to the floor of the sinus regeneration is then performed. and to widen the interradicular bone, in anticipa- tion of accepting a tapered end implant with a Figure 49: A radiograph taken four years after implant 4.1 mm wide “apex” and a 6.5 mm wide restor- restoration demonstrates stable peri implant bone levels. ative platform. The interradicular osteotomy is widened to 3.5 mm, the implant is inserted, and an appropriate regenerative materials and flap designs are employed as already discussed. It should be noted that appropriate diagno- sis of the morphology and health of the residual interradicular bone cannot usually be carried out prior to tooth sectioning and root removal. The only view afforded to the clinician by a peri- apical radiograph is the interradicular bone mor- phology and quantity between the mesiobuccal and disto buccal roots of the first molar. The implant will be stabilized by the bone between The Journal of Implant & Advanced Clinical Dentistry 85

Fugazzotto Figure 50: A patient presents with a vertically fractured Figure 51: A radiograph taken six months post maxillary rst molar. Radiographically, inadequate bone interradicular bone manipulation and implosion, implant appears to be present for implant placement at the time placement, and concomitant regenerative therapy, of tooth removal. However, the radiograph only shows demonstrates complete bone ll around the implant. the bone between the buccal roots. The radiograph gives no indication of the quantity of bone between the buccal roots and the palatal root. Figure 52: A radiograph taken seven years post restoration the buccal roots and the palatal root. Therefore, demonstrates stable peri implant bone levels. a radiograph taken prior to tooth removal will offer limited information in situations where the buccal roots are convergent and/or fused. Such a situation is demonstrated in Figures 50-52. The decision tree described offers a frame- work in which to predictably augment the posterior maxilla with or without simultane- ous implant placement at the time of maxil- lary molar extraction. A recent publication23 documents 391 sites treated through implant placement at the time maxillary molar extrac- tion. A combination of parallel wall and tapered implants were utilized. After a mean time of 30.9 months in function, the cumula- tive success rate of the implants was 99.5%. 86 Vol. 2, No. 1 February 2010

Fugazzotto CONCLUSIONS Disclosure The author reports no conflicts of interest with anything mentioned in this article. The continued development of new tech- niques and the evolution of our understand- References ing of the potentials and limitations of various 1. Becker W, Becker BE, Berg L, et al: New attachment after treatment with root therapies over time afford the conscien- tious clinician more than adequate informa- isolation procedures. Report for treated class III and class II furcations and tion to ascertain when to utilize root resective, vertical osseous defects. Int J Periodontics Restorative Dent 1998; 8(3): 8-23. or implant and regenerative therapies, in the 2. Goldman MJ, Ross IF, Goteiner D: Effect of periodontal therapy on patients treatment of compromised maxillary and man- maintained for 15 years or longer. A retrospective study. J Periodontol 1986; dibular molars. It is incumbent upon us all to 57: 347-353. employ this knowledge to maximize treatment 3. McFall WT: Tooth loss in 100 treated patients with periodontal disease – a outcomes in the most efficient and reason- long-term study. J Periodontol 1982; 53: 539-549. able manner. Our patients deserve no less. 4. Wood WR, Greco GW, McFall WT Jr: Tooth loss in patients with moderate periodontitis after treatment and long-term maintenance. J Periodontol 1989; Correspondence: 60: 516-520. Paul A. Fugazzotto, DDS 5. Hirschfeld, L, Wasserman B: A long-term study of tooth loss in 600 treated 25 High Street periodontal patients. J Periodontol 1978; 49:225-237. Milton, MA 02186 6. Wang HL, Burgett FG, Shyr Y, et al: The influence of molar furcation 617-696-7257 - phone involvement and mobility of future clinical periodontal attachment loss. J 617-696-6635 - fax Periodontol 1994; 65: 25-29. [email protected] 7. Fleischer HC, Mellonig JT, Brayer WK, Gray JL, Barnett JD. Scaling and root planning efficacy in multi-rooted teeth. J Periodontol 1989; 60: 402-409. 8. Carnevale G, DiFebo G, Tonelli MP Marin C, Fuzzi M. A restorative analysis of perio-prosthetic treatment of molars with interradicular lesions. Int J Periodontics Rest Dent 1991; 11(3): 189-205. 9. Basten CH, Ammons WF, Persson R. Long term evaluation of resected molars: A retrospective study. Int J Periodontics Rest Dent 1996; 16(3): 206-219. 10. Carnevale G, Pontoriero R, and DiFebo G. Long term effect of root resected therapy in molars. A 10 year longitudinal study. J Clin Periodontol 1998; 25(3): 209-214. 11. Ricchetti. Unpublished. Furcation treatment by root removal I. Results over 10 years. 12. Ricchetti. Unpublished. Furcation treatment by root removal II. Results after 18 years. 13. Fugazotto P. Comparison of success of root resected molars and molar implants in function: Results up to 16+ years. J Periodontol 2001; 72(8): 1113-1123. 14. Blomlof L, Jansson L, Appelgren R, Ehnevid H, Lindskog S. Prognosis and mortality of root resected molars. Int J Periodontics Rest Dent 1997; 17(2): 190-201. 15. DeSanctis M, Murphy KG. The role of resective periodontal surgery in the treatment of furcation defects. Periodontol 2000 2000; 22: 154-168. 16. Ricchetti PA. A furcation classification based on pulp chamber furcation relationships and vertical radiographic bone loss. Int J Periodontics and Rest Dent 1982; 5(2): 50-59. 17. Bowers GM, Schallhorn RG, McClain PK, Morrison GM, Morgan R, Reynolds MA. Factors influencing the outcome of regenerative therapy in mandibular Class II furcations. J Periodontol 2003; 74(9): 1255-1268. 18. Sanj and Giovannali. Focus on furcation defects: Guided tissue regeneration. Periodontology 2000 2000; 22: 169. 19. Fugazzotto PA. Implant and Regenerative Therapy in Dentistry: A Guide to Decision Making Iowa: Wiley-Blackwell, 2009. 20. Fugazzotto PA. Report of 302 consecutive ridge augmentation procedures: technical considerations and clinical results. Int J Oral Maxillofac Implants 1998; 13(3): 358-386. 21. Fugazzotto PA. Maintenance of soft tissue closure following guided bone regeneration: technical considerations and report of 723 cases. J Periodontol. 1999 70(9): 1085-1097. 22. Fugazzotto PA. Maintaining primary closure after guided bone regeneration procedures: introduction of a new flap design and preliminary results. J Periodontol 2006; 77(8): 1452-1457. 23. Fugazzotto PA. Implant selection and treatment protocols at the time of maxillary molar extraction: rationale and report of results. J Periodontol 2008; 79(2): 216-223. The Journal of Implant & Advanced Clinical Dentistry 87





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Does the Addition of an O -Angle View Shintaku et al Improve Root Fracture Detection? Werner H. Shintaku, DDS, MS1 2 Marcel Noujeim, DDS, MS3 4 Abstract Background: To identify dental fractures, more display the images. No imaging enhancement than one image with differing angles is often tools were allowed. The diagnostic accuracy indicated. The aim of this study was to evalu- was assessed by means of a 5-point receiver ate the efficacy of using more than one intraoral operating characteristic (ROC) curve analysis. projection for the detection of dental fractures. Results: The mean area under the ROC curve Methods: From 10 dry mandibles, 41 poste- (Az) for one image was 0.743 and 0.755 for rior teeth were included in this study. Intraoral two images. Respectively, sensitivity pre- film-based radiographs were taken from 25 non- sented values of 51.29% and 58.13%, and fractured and 16 fractured teeth. Each region specificity was 88.4% and 86%. Accuracy was imaged twice with different horizontal was 73.9% and 75.11%. Using t-test, none angulations using conventional Kodak Insight of these values were statically significant. Film (Eastman Kodak, Rochester, NY). These films were digitally converted using a scan- Conclusion: This study suggests that the use ner in 600 dpi with maximum resolution, and of more than one projection may not efficiently exported as tagged image file format (TIFF) detect dental fractures. If a dental fracture is files. In two sessions, these images were evalu- suspected and not visible with one film, more ated by 10 dentists with experience viewing than two projections with different angulations, digital radiographies in a room with dimmed or even more advanced imaging modalities background light. Dedicated imaging soft- such as high resolution cone-beam computed ware (DIMEX, Planmeca, Finland) was used to tomography (CBCT) should be considered. KEY WORDS: Dental radiography, dental fracture, intraoral radiography, periapical radiography 1. Resident, Department of Diagnostic Science, The University of Texas Health Science Center at San Antonio Dental School, San Antonio, Texas, USA 2. Assistant Professor, Division of Health Promotion, Disease Prevention and Epidemiology, University of Southern California School of Dentistry, Los Angeles, California, USA 3. Assistant Professor and Program Director, Department of Diagnostic Science, The University of Texas Health Science Center at San Antonio Dental School, San Antonio, Texas, USA 4. Professor, Department of Diagnostic Science, The University of Texas Health Science Center at San Antonio, Dental School, San Antonio, TX The Journal of Implant & Advanced Clinical Dentistry 91

Shintaku et al INTRODUCTION absence of fractures, each tooth was removed from its alveolus and visually evaluated. Six- Fractures of dental structures frequently repre- teen teeth were artificially fractured using a sent a diagnostic dilemma to the dentist and the vertical force with a mallet and 25 were left sooner a correct diagnosis is made the greater the intact. The fragments were held together chances of saving the tooth. Dental fractures are using a cyanoacrylate-based adhesive (Super- common in patients involved in traffic accidents, glue Corporation, CA) in order to secure sports and violence, but some other fractures the stability of the fractured tooth during the are described as not related to impact trauma.1 handling and image acquisition processes. Many morphologic, physical, and iatrogenic fac- tors, such as deep grooves, pronounced intraoral Image acquisition temperature fluctuation, poor cavity preparation Periapical radiographs were obtained with design, and wrong selection of restorative materi- using a bite block and paralleling technique als may predispose posterior teeth to an incom- (Rinn XCP, Dentsply, IL) with Kodak Insight plete fracture.2 3 Therefore, dentists can be faced X-ray films (Eastman Kodak, Rochester, NY). by unusual cases of patients complaining of oro- In order to place the films in the same posi- facial symptoms that may not completely resolved tion, dental impression material (Reprosil Easy by a clinical examination.4 In these cases, imaging Mix Putty, Dentistply, Elgin, IL) was used with plays an essential role in the identification of den- each intraoral positioner. The radiographs were tal fractures supporting all aspects from diagno- taken bucco-lingually in an orthogonal direc- sis and treatment planning to assessing outcome. tion and eccentrically with a horizontal angle of 10 to 15° mesially or distally to the initial expo- The interpretation and identification of dental sure. A support to the tube head and the man- fractures using radiographs is one of the most dif- dible was specially designed to stabilize the ficult tasks in dental care.5 Since the X-ray beam projection between radiographic exposures (fig- needs to pass through the space between the frag- ure 1). The focus-receptor distance was fixed ments and hit the receptor in order to clearly iden- at 40cm and a soft-tissue equivalent material tify the fracture, the angle of the X-ray beam plays consisting of 20mm acrylic bloc was placed an important role in the proper evaluation of dental between the beam indicating device. Films fractures.6 In several cases, more than one projec- were exposed using a Planmeca “Intra” unit tion is proposed for proper evaluation and diagno- (Planmeca, Finland) operating at 60kVp, 8mA sis. The aim of this paper is to evaluate the efficacy with a filtration of 1.5mm aluminum equivalent. of using one additional projection with different hor- The ideal exposure time for each projection was izontal angulation for the evaluation of dental frac- defined in a pilot study, when all dental struc- tures while using intraoral periapical radiographs. tures could be differentiated in the image with a consistent density. For this study the expo- MATERIALS AND METHODS sure time varied from 0.16 seconds to 0.20 seconds. All intra-oral films were processed in Tooth preparation Forty-one teeth from 10 dry mandibles were selected for this study. In order to confirm prior 92 Vol. 2, No. 1 February 2010

Shintaku et al the same A/T2000 (Air Techniques, Hicksville, Figure 1: Optical bench used to ensure consistent NY) according to the manufacturer’s recom- projection geometry. mendations, at 81oF with new developer and fixer. All films were digitized using an Expres- Figure 2a/b: Set of lms used in this study. Film in sion 1680 flat-bed scanner (Epson Inc, Long orthoradial orientation (a). Image from PID in mesial/Distal Beach, California) at resolution of 600 dpi angle to the initial orthoradial lm (b). and 8-bit grayscale. Images were saved as lossless tagged image file format (TIFF) files. Data analysis Diagnostic accuracy of each observer was Image evaluation evaluated by receiver operating characteris- Ten observers with experience in evaluation of tics (ROC) curve analysis for both observa- digital images were asked to identify the pres- tion sessions. The area under the ROC curve ence or absence of dental fracture in each represented the diagnostic accuracy of the tooth using a 5-point rating scale: (1) defi- method. Accuracy increases as this value nitely absent; (2) probably absent; (3) unsure; approaches 1, which indicates perfect per- (4) probably present; (5) definitely present. formance. The mean values of data obtained The observers had no prior knowledge of the distribution of the teeth with fractures. The radiographs were numbered and displayed on a 15 inch Dell TFT monitor (Dell Inc., USA) with resolution setting of 1280 x 1024 pixels in two different sessions. T he viewing time was unre- stricted and viewing distance was 80 to 100 cm in a room with dimmed background lighting. In the first session, the observers evaluated all radiographs taken in a routine orthogonal pro- jection (figure 2a). In the second session, the observers evaluated in the same screen the ortho-radial projections with the radiographs taken in a different horizontal angulation (figure 2b). In order to prevent correlation between the radiographic reading sessions, a minimum of one week interval was given between suc- cessive evaluations to preclude any learn- ing bias. The digital images were displayed using Dimaxis Pro software (Planmeca, Fin- land), and the observers were not allowed to use image-enhancement tools of the software. The Journal of Implant & Advanced Clinical Dentistry 93

Shintaku et al by the observers for each session were cal- presented significant difference between culated using ROC Analysis software.7 The the methods (t = 0.4, p > 0.05), but area under the curves (AZ) was computed two readers presented decreased accu- for each observer and viewing session, and racy value, five increased their accu- was used to assess the detection accuracy. racy and three maintained their accuracy. From the same data, the diagnostic sensi- DISCUSSION tivity and specificity was calculated for each observer and reading session corresponding to Sometimes patients complain of inexplicable the number of images provided. The scores on persistent pain in the orofacial region.8 After the confidence-rating scale were dichotomized thorough investigation, dentists may conclude for this purpose. Scores of 1 to 3 were consid- that a dental fracture is one of the possible eti- ered as denoting “Fractures Absent’’ and 4 to 5 ologies for these symptoms. The identification as “Fractures Present’’. T-test was used to verify of these fractures represents a clinical challenge the significance between the obtained values. with regard to their diagnosis, treatment plan, and prognosis.9 Since exploratory observation is RESULTS not always possible, radiology plays an essential role in the diagnosis and management of these The values of ROC area (Az), sensitivity, specific- cases. Radiology helps to identify the location ity and accuracy values for each evaluator are and orientation of fractures and indicates the provided in table 1. The difference between the degree of separation or displacement of the mar- Az value were not statically significant between gins. Unfortunately, conventional radiographic 1-film and 2-film viewing. Individually, seven images present inherited limitations. Mainly due of the readers presented higher Az values for to geometric factors, fractures are missed if the two-film system, but the t-test did not indicate x-ray beam does not pass through the fracture a significant statistical difference between the line and hit properly the image receptor. Even use of one or two films (t = 0.497, p > 0.05). so, familiarity with the technique, accessibility and low cost continue to be the main advan- The sensitivity values for the identification of tages of conventional radiography. In cases of dental fractures when two films were provided dentoalveolar trauma, there is no recommended increased in six readers, decreased in two read- standard series of radiographs.10 Commonly, ers and had the same value for two readers. No multiple incidences at different angles or even statistical difference was found by the t-test different techniques including extraoral radi- between the two groups (t = 0.194, p > 0.05). ography are indicated for the identification of dental fractures.11-13 Unfortunately, when more For specificity, two readers presented than one image is necessary, this results in higher values when two images were pre- increased radiation exposure for the patient. sented; four readers had lower values and This study compared the sensitivity, specificity had the same value in four. No statistical dif- and accuracy in the detection of experimental ference was found by the t-test between the two groups (t = 0.296, p > 0.05). The degree of accuracy also did not 94 Vol. 2, No. 1 February 2010

Shintaku et al 01 0.729 0.751 56.3 50.0 92.0 100 78.0 80.5 02 0.761 0.799 62.5 62.5 92.0 92.0 80.5 80.5 03 0.749 0.806 56.3 56.3 92.0 92.0 78.0 78.0 04 0.765 0.745 43.8 50.0 92.0 84.0 73.2 70.7 05 0.696 0.624 56.3 37.5 84.0 84.0 73.2 65.9 06 0.641 0.718 56.3 87.5 72.0 56.0 65.9 68.3 07 0.835 0.75 56.3 62.5 88.0 88.0 75.6 78.0 08 0.756 0.841 31.3 62.5 96.0 88.0 70.7 78.0 09 0.739 0.744 50.0 62.5 80.0 84.0 68.3 75.6 10 0.759 0.781 43.8 50.0 96.0 92.0 75.6 75.6 root fractures when two images were provided. This study varied the horizontal angulation The variation in horizontal angulation consisted only in mesial or distal direction, and a differ- in 10 to 25 degrees from the initial projection ent result may be obtained if both incidences to resemble the common clinical environment. are used resulting in at least three final images. A ROC curve was chosen because it is a The overall result of this study showed that well-established form to visually organize and using two images only improved slightly the evaluate imaging techniques taking in consid- identification of root fractures without statis- eration the performance of evaluations.14 In tical significance. One of the possible rea- our study, the t-test showed no significant dif- sons for this result may be related to the lack ference in sensitivity, specificity and accuracy of established methodology for the incidences. values as well as in the Az area. This result However, even using multiple incidences, if indicates that the use of two incidences with the x-rays were not able to pass through the the above described angles were not differ- fragments, there is a chance to miss the frac- ent statistically from using only one incidence. ture with unnecessary exposure of the patient The Journal of Implant & Advanced Clinical Dentistry 95

Shintaku et al to radiation. Therefore, if the clinical or indi- even more advanced imaging modalities such as rect radiographic findings, such as the widen- high resolution CBCT should be considered. ing of the periodontal ligament space, highly suggest the presence of dental fractures, Correspondence: more than two exposures at different angles or Werner H. Shintaku, DDS, MS advanced imaging modalities, like high resolu- The University of Texas Health Science tion cone-beam computed tomography (CBCT), Center at San Antonio may be indicated for more definitive diagnosis. Dental School, Dental Diagnostic Science Mail Code 7919 CONCLUSION 7703 Floyd Curl Drive San Antonio, TX 78229-3900, USA This study suggests that the use of more than Telephone: +01-213-448-0255 one radiographic image may not efficiently detect Fax: +01-210-567-3334 dental fractures. If a dental fracture is sus- e-mail: [email protected] pected and not visible with one film, more than two projections with different angulations, or 8. Clark GT. Persistent orodental pain, atypical odontalgia, and phantom tooth pain: when are they neuropathic disorders? J Calif Dent Assoc 2006;34(8):599-609. Disclosure The authors report no conflicts of interest with anything mentioned in this article. 9. Cohenca N, Simon JH, Roges R, Morag Y, Malfaz JM. Clinical indications for digital imaging in dento-alveolar trauma. Part 1: traumatic injuries. Dent Traumatol References 2007;23(2):95-104. 1. Rivera EM, Williamson A. Diagnosis and treatment planning: cracked tooth. Tex 10. Dale RA. Dentoalveolar trauma. Emerg Med Clin North Am 2000;18(3):521- Dent J. Mar 2003;120(3):278-283. 538. 2. Geurtsen W, Schwarze T, Gunay H. Diagnosis, therapy, and prevention of the 11. White SC, Pharoah MJ. Trauma to teeth and facial structures. 5th ed. St. Louis: cracked tooth syndrome. Quintessence Int 2003;34(6):409-417. Mosby; 2004. 3. Gutmann JL, Gutmann MS. Cause, incidence, and prevention of trauma to teeth. 12 Andreasen FM, Andreasen JO. Diagnosis of luxation injuries: the importance Dent Clin North Am. Jan 1995;39(1):1-13. of standardized clinical, radiographic and photographic techniques in clinical investigations. Endod Dent Traumatol 1985;1(5):160-169. 4. Shintaku W, Enciso R, Broussard J, Clark GT. Diagnostic imaging for chronic orofacial pain, maxillofacial osseous and soft tissue pathology and 13. Camp JH. Management of sports-related root fractures. Dent Clin North Am temporomandibular disorders. J Calif Dent Assoc 2006;34(8):633-644. 2000;44(1):95-109, vi-vii. 5. Kositbowornchai S, Sikram S, Nuansakul R, Thinkhamrop B. Root fracture 14. Swets JA. Measuring the accuracy of diagnostic systems. Science detection on digital images: effect of the zoom function. Dent Traumatol 1988;240(4857):1285-1293. 2003;19(3):154-159. 6. Moule AJ, Kahler B. Diagnosis and management of teeth with vertical root fractures. Aust Dent J 1999;44(2):75-87. 7. Eng J. ROC analysis: web-based calculator for ROC curves. Available at: http:// www.jrocfit.org. Accessed April 10, 2009. 96 Vol. 2, No. 1 February 2010

Course Outline Sinus Augmentation Techniques- Lateral and Crestal Approaches Complications associated with sinus augmentations Minimally Invasive Antral Membrane Elevation- Introduction,case presentation and step by step procedure Hands on sinus models surgery using the dedicated balloon kit Course date: April 11th 2010 Location : DoubleTree Hotel, Times Square NYC Tuition fee: $1949 For registration please call 914-7233366 or log into: www.augmentationcourse.com Dr Mazor is a leading Israeli periodontist. World known researcher and lecturer on state of the art surgical implant procedures and bone regeneration. Conducts International continuing education courses on implant dentistry. Dr Horowitz is part of the faculty at The NYU College of Dentistry in the Departments of Periodontics, Implant Dentistry and Oral Sugery. World known researcher and presenter on implant site development and bone regeneration.