Cairo Dental Journal (25) Number (1), 61:67 Janurary, Tamer N. Mohamed; 1 Abd El Salam B. Younis 2 and Basma G. Moussa 3.

Transcription

1 Cairo Dental Journal (25) Number (1), 61:67 Janurary, 2009 IMMEDIATE IMPLANTS IN LOWER POSTERIOR TEETH WITH BONE SUBISTITUTE AND GUIDED TISSUE MEMBRANE Tamer N. Mohamed; 1 Abd El Salam B. Younis 2 and Basma G. Moussa Oral Surgeon, Ahmed Maher Hospital, Ministry of Health. Prof, Oral Surgery Department, Faculty of Oral & Dental Medicine, Cairo University. Ass Prof, Oral Surgery Department, Faculty of Oral & Dental Medicine, Cairo University. Abstract Immediate dental implants offer number of significant advantages to both the patients and the clinicians. The most important one is that without the support provided by functioning dental unites; the bony receptor site soon undergoes a catabolic phase that results in varying amounts of atrophy after tooth extraction. The aim of this study is to evaluate clinically and radiographically the use of immediate implants in lower posterior teeth with hydroxyapitite bone substitute and guided tissue membrane. Methods: Eight patients were selected for immediate implants installation after extraction of mandibular molars or premolars followed by placement of hydroxyapitite bone substitute together with GORE-TEX membrane. Assessments of the implants were done both clinically and radiographically at one, three and six months post-loading. Results: There was a decrease of Probing Depth, Bleeding Index and Gingival Index throughout follow-up period. While there was an increase in marginal bone height and bone density around implants Conclusion: This study proved that using a bone filling material and guided tissue membrane as GTR around immediate implants is a suitable method for inducing new bone formation in immediate implant surgery. Key words: Immediate implant, GORE-TEX membrane, Hydroxyapitite bone substitute. INTRODUCTION Immediate implant placement following tooth extraction in appropriately selected cases has been considered the optimal procedure for the following reasons: the natural healing process are mobilized to the maximum, no bone resorption has taken place yet, drilling is reduced, a number of surgical stages are eliminated, design and construction of prosthesis is simplified, and positive psychological effect on the patient. (1,2) The posterior mandible is a common site for the consideration of implant placement because of the premature loss of molars. However, their use is

2 (62) Tamer N. Mohamed, et al. C.D.J. Vol. 25. No. (I) complicated by the anatomic obstacles of the inferior alveolar nerve, a variety of malformations of the ridges, the presence of softer bone, and little or no possibility of reinforcement via bicortical stabilization. (3,4) Guided bone regeneration (GBR) for treatment of insufficient bone volume around implants can be performed using membranes with or without grafting materials. Many bone substitutes can be used including autogenous, allogenous, xenogenous or alloplastic grafts. (5) Finding an ideal bone substitute material for grafting has been the goal of researches for many years, several bony substitutes have been popularized during the past 10 years, these materials may be considered osteoconductive, where the implanted material serves as a scaffold for the ingrowth of capillaries, perivascular tissue, and osteoprogenitor cells from the recipient bed. (6) Clinical studies showed that tricalcium phosphate bioceramics, as well as bioactive glass, can contribute to the maintenance of the alveolar ridge. Despite clinical limitations of adequate histological analysis, the results with osteoconductive materials especially those related to hydroxyapitite and tricalcium phosphate seem very encouraging. (5,7) Barrier membranes have been developed to allow guided tissue regeneration by the principle of osteopromotion. The material is chemically and biologically inert. However, non resorbable and resorbable membranes are available in the market, the non resorbable e-ptfe (Expanded Poly Tetra Floro Ethylene) (Gore-Tex,) remains the most widely used membrane. (6,8,9,10) Wilson, (11) reported that to achieve better clinical outcomes, the GBR barrier should possess the following properties, cell exclusion, tenting, scaffolding, stabilization and frameworking. As, the success rates of immediate implants without guided tissue regeneration (GT.R) placed in the posterior region of both jaws are less than the anterior segment, (12) so, this study aimed to evaluate clinically and radiographically the use of immediate implants in lower posterior teeth with hydroxyapitite bone substitute and guided tissue membrane. Materials and Methods Eight healthy adult patients were selected from Outpatient Clinic, Department Of Oral Surgery, Faculty of Oral and Dental Medicine, Cairo University for placement of implants immediately after extraction of nonrestorable lower posterior teeth (premolars and molars). After routine clinical examination preoperative periapical and panoramic radiograph were done for each patient to detect any pathosis at the area for implant placement as well as the quality of bone at this area and the degree of approximation to related anatomical structures (Fig.1). To determine the suitable length, diameter and location of the implant: resin stent with an attached metallic ball marked with a determined diameter was used and a panoramic radiograph were taken so, the actual length of both tooth and implant could be determined from the following formula: Real diameter of ball Diameter of ball in radiograph Real diameter of root Diameter of remaining root in radiograph Fig. (1) Part of panoramic radiograph showed sever bone resorption around first mandibular molar. =

3 IMMEDIATE IMPLANTS IN LOWER POSTERIOR (63) Stage I surgery Drilling and preparation of implant seat was done using standard drills at the socket of the extracted teeth.the diameter of implant hole was prepared according to the diameter of the selected implant. 1 The depth of implant seat was at least 2 3 mm apical to the socket. Then dense hydroxyapitite 2 was packed around the implant filling the residual socket. The healing screw with attached GORE TEX membrane, 3 was screwed to the implant fixture (Fig. 2). Flap was repositioned to obtain primary wound healing. Clinical evaluation was done at one, two and four month preloading, then at one, three and six month after loading including: Probing depth, bleeding index and gingival index. Radiographic evaluation was done at same follow-up post-loading periods using periapical and panoramic radiographs to assess marginal bone height and bone density mesial and distal to implant fixture using the parallel technique software of the Digora system. Radiometric data are used to determine relative changes in the density of bone by quantifying the mean gray values of image. (Fig 4). Fig. (2) Photograph showing GORE-TEX membrane attached to sealing screw over the implant and hydroxyapitite. Stage II surgery Fig. (3) Photograph showing a porcelain crown over the implant as a restoration of the first premolar of the mandible. This phase was carried out after 4 months of the first stage as follows: A crestal incision over the implant was done and a flap was reflected to remove the cover screw. The abutment of the corresponding diameter of the implant was screwed into the fixture and left for one week,then the suprastructure was fabricated & cemented in its place (Fig 3). 1. Tut-2 Implant, Egyptian Co. for dental implant,egypt. 2. Osteograf D-700 Cera med Co. USA. 3. GORE-TEX regenerative material, Cera sorb Co, USA. Fig. (4) Photograph showing bone density measurement around implant after digitization of the periapical radiograph using Digora system.

4 (64) Tamer N. Mohamed, et al. C.D.J. Vol. 25. No. (I) Results Eight patients four males and four females with average age forty four years were evaluated for immediate implants. Six cases were in molar region & two in premolar region. Five cases were in the right side and three in left side. The causes of extraction was in four cases badly decayed teeth, in one case periodontally affected teeth and in three cases the teeth were extracted for both reasons. Pre-loading clinical evaluation The eight patients were followed up at one, two and four months postoperatively. At the first week postoperative some discomfort was reported without any complaint of sever pain or major edema. All wounds healed properly during follow-up period except one case which developed wound dehiscence and was treated by secondary closure. (buccal, lingual, mesial & distal) for all implant abutments. At three months follow-up period a decline in the gingival index score was noticed than first month. At six months follow up period, further decline in gingival index score was shown. Radiographic finding Both marginal bone height and bone density were evaluated for all cases throughout the post-loading followup period. For the marginal bone height measurements, there were decrease in the marginal heights around all implants at the three months post-loading period and then increase in the six months post-loading period. While for the bone density, there was increase in the bone density around the implants at the periods of post-loading follow-up (Figs 5,6&7 ). Post-loading evaluation This was done one, three and six months post loading; as following : implant mobility which was tested using the Miller Mobility Index (MI) scores (13) There were 4 cases that showed no mobility during the follow-up period. The other 4 cases showed decline in the mobility index scores through the follow-up period. The percussion was with metallic ringing indicating ankylotic implant in cases with no mobility. While, less metallic sound was observed in the other cases. Probing depth was measured for each implant for the four surfaces collectively (buccal, lingual, mesial and distal). At one month post loading, the average probing depth was 2.03 mm, at three month, it declined to 1.4mm, and at six month follow-up period, depths decreased to 0.74mm. There was gradual decrease in probing depths measurements during the study period. Fig. (5) Graph showing the average marginal bone height through the post loading follow-up period. Values of the bleeding index were measured from the four surfaces collectively around all implant abutments. At the three months follow-up period the bleeding index value showed a decline and a further decline was apparent at the six months follow-up period. Condition of peri-implant tissue where gingival index scores were measured of the four surfaces collectively Fig (6) Graph showing the average bone density through the post loading follow up period.

5 IMMEDIATE IMPLANTS IN LOWER POSTERIOR (65) bone formation. Another opinion attributed to the rigidity of the grafting material allows to conform the required bone shape which prevent collapse after surgery. Fig (7) Periapical radiograph three month post loading showing increase bone density around implant. Discussion Immediate implants after extraction is one of the successful treatment modalities for dental restorations. (11,14,15) The advantages of the immediate placement of implant into extraction sites are three folds, the first of these is the significant reduction in treatment time for the patient. The second advantage is the preservation of ridge height, which may be severely compromised post extraction in instances of trauma and root fracture. The final advantage, directly related to the greater bone volume resulting from ridge preservation. (16,17) In the current study, eight self tapping immediate implants were inserted after extraction of nonrestorable mandibular posterior teeth. Hydroxyapitite grafting material and e-ptfe were used with implants to prevent the mucosal tissue from collapsing into the socket, to stabilizes the blood clot within the socket, to inhibits the ingrowth of epithelial tissue of oral cavity into the socket. Condensation of the graft was done very lightly around the implant leaving spaces within the graft. This thought to give a good chance for the formation of an organized blood clot, which will enhance bone deposition and collagen fiber production by the migrating progenitor cells. Linde (18) proved that there is a relation between the rigidity of the grafting material and the amount of new bone formation. As the more the rigidity the more the new As, mobility of the implant is the most significant of implant failure i.e. detection of mobility means failure of osseointegration even in the absence of other signs or symptoms (19). The Gingival Index was used by several authors (13, 20) to assess the peri-implant tissue health and to detect any alterations in color, contour and consistency, while Linde (18) used Bleeding Index instead of Gingival Index as an indicator of inflammation. In the present study, four cases have shown no mobility through-out the post-loading follow-up period and other cases showed gradual decline in the Mobility Index scores and decrease in Gingival,Bleeding indices as well as Probing depth during the follow-up period. This indicated healing of soft tissue attachment around the implant and absence of peri-implant disease due to extensive oral hygiene instructed to the patients. This is in agreement with Linkow et al, (22) who stated that periodontal indices were not directly related to the success or failure of osseointegration of implants. They used for monitoring peri-implant soft tissue. In previous studies (21,22,23) which suggested that radiographic interpretation of alveolar bone levels has proved to be one of the most valuable tools for evaluation of implant success. This was in agreement with usage of the radiographic and probing measurements to get a good peri-implant assessment. (19) Conventional radiography was not used to evaluate bone height or density because % of the bone mineral content must be lost before changes in bone density are detected. (24) So in this study, radiographic measurements of bone levels were carried out through digitized radiographs that were analyzed by Digora software using the parallel technique to measure the amount of bone loss and bone density. In the present study marginal bone height loss due to function observed at first three months post-loading due to graft resorption was followed by increase in the marginal bone height level as remodeling of the graft occurred.

6 (66) Tamer N. Mohamed, et al. C.D.J. Vol. 25. No. (I) Linear density measurements were applied rather than area measurements in evaluating bone density to assure accurate bone assessment without any overlapping over the measured area which might subject the results to measurement errors. The density of dental image refers to its brightness. (25) There was a slight increase of bone density for all implants through follow-up period in the present study This could be attributed to presence of bone grafting material with high mineral concentration. Further more bone density increased at the end of this study in agreement with Adell et al, (26) who concluded that bone mass is a direct result of the mechanical usage of the skeleton. Conclusions The clinical and radiographic results of this study demonstrated that immediate implant placement in combination with hydroxyapitite bone substitute and GORE-TEX guided tissue membrane are suitable methods for inducing new bone formation around implant especially in cases of severe bone resorption. References 1. Zahnmed SM: Prevention of alveolar ridge resorption after teeth extraction Int J Oral Maxillofac Surg. 114: 328, Esposito M, Grusovin MG, Kwan S, Worthington H V, Coulthard P: Intervention for replacing missing teeth: bone augmentation techniques for dental implant treatment. Aust Dent J. 70: Abubaker O, Benson K: Oral and Maxillofacial secrets, Hanley,Beflus inc ; Philadelphia. PP 309, Coatoam G, Mariotti A: Immediate placement of anatomically shaped dental Implants. J Oral Implantol. 26:170, Michael M, Chali GE, Peter E, Larrsen D: Petreson s Principles of oral and maxillofacial surgery. 2 nd ed. BC Becker Inc Hamstton,London. PP 240, Augthun M, Yildirim M, Spiekermann H, Biesterfeld S: Healing of bone defects combination with immediate implant using the membrane technique. Int J Oral Maxilofac Implant. 421:10,993. Alexander C, Luis Guiherme B, Pentegan J, Arthur B: Histomorphmetric analysis of rat alveolar wound healing with Hydroxyapitite alone or associated to BMPS; Braz Dent J. 60: 450,2002. Simon M, Trisi P, Piattelli A: Vertical ridge augmentation using a membrane technique associated with ossointegrated, implants. Int J Periodont Rest Dent. 14: 497, Rominge J W,Triplett R G: The use of guided tissue regeneration to improve implant osseointegraion. J Oral Maxillofac Surg. 52:106, Schliephake H, Dard M, Planck H, Hierlemann H, Jakob A.: Guided bone regeneration around endosseious implants using a resorbable membrane VS e PTFE membrane. Clin. Oral Impl.Res:11:230, Wilson TG: Guided tissue regeneration around dental implants in immediate and recent extraction sites. Initial observations. Int J Periodont Rest Dent. 12: 185, Laurel N, Lang NP : Variations in bone regeneration adjacent to implants augmented with barrier membranes alone or with demineralized freeze dried bone autologous grafts; a study in dogs. Int J Oral Maxillofac Implants. 1:143, rd 13. Miller SC: Textbook of Periodontia. 3 ed, Blankiston Inc Pub, Philadelphia. PP 215, Ganeles J, Wismeijer D: Early and immediate tooth and partial arch applications. Int J Oral Maxillofac Implants. 92:102, Apse P, Zarb GA, Schmitt A, Lewis DW: The longitudinal effectiveness of osseo- integrated dental implants. The Toronto study: peri-implant mucosal response. Int J Periodont Rest Dent. 11:95, Misch CE : Root for surgery in the edentulous mandible: Stage I implant insertion.contemporary implant dentistry. Mosby Co, London. PP Castellon P, Yukna: Immediate dental implant placement in sockets augmented with HTR synthetic bone. Implant Dent. 42:13, 2004.

7 IMMEDIATE IMPLANTS IN LOWER POSTERIOR (67) 18. Linde A: Evaluation of guided bone regeneration around 23. Languor B, Sullivan DY: Osseointegration: Is impact on the implants placed into fresh extraction sockets: An experimental interrelationship of periodontics and restorative dentistry: Part study in dogs. J Oral Maxillofac Surg. 51: 885, III periodontal prosthesis redefined. Int J Periodot Res Dent. 19. Schulte B, D Hoedt D, Gomez A, Gomez G : The first 15 9:241,1989. years of the Tubingen implant and its further development to the Frialite 2 system. J Dent Implantol. 15:75, Jeffcoat MK: Digital radiology for implant treatment planning and evaluation. J Dento Maxillofac Radiol. 21:203, Loe H, Silness J: Periodontal disease in pregnancy prevalence and severity. Acta Odontol Scand. 21:532, Shrout MK, Zebell RM, Potter BJ, Hildebot CF : Intrafilm controls to standardize grey level variations in digitized 21. Forum S: Immediate placement of Implants into Extraction radiographs. J Dento Maxillofac Radial. 24: 221, sockets: Rational, outcomes, Technique Alpha Omega. 98: 30, Adell R, Lekholm U, Rocklar B, Branmark PI, Lindhe J: Marginal tissue reactions at osseointegrated titanium fixtures. 22. Linkow LI, Rinaldi AW, Weiss WW, Smith GH: Factors influenc- A 3-year longitudinal prospective study. Int J Oral Maxillofac ing long term implant success. J Prosth Dent. 63:64, Surg. 15:39,1986.