Faculty Bibliography

Prosthodontic rehabilitation of an atrophic edentulous maxilla can be challenging and is further complicated when multiple risk factors are present. Fixed prostheses require multiple implants for support/retention organized in biomechanically favorable positions in order to afford a good prognosis. Such suitable implant arrangements in an atrophic edentulous ridge can often be difficult to achieve. Removable prostheses require fewer implants for a favorable prognosis and can furthermore take advantage of the additional anatomical structures for support/retention. This clinical treatment will describe the fabrication of a partial palatal coverage overdenture retained by zygomatic implants.

PURPOSE:: To analyze crestal bone loss changes that may affect the gingival height around an implant and bone loss in interproximal areas. When implants are placed adjacent to one another, interimplant bone loss around 1 implant may combine with the implant bone loss around the adjacent implant to affect the crestal bone loss interproximally. MATERIALS AND METHODS:: The primary objective of this study was to evaluate histologically and histomorphometrically the effect that this implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by 2 different distances: 4 mm and 3 mm. A secondary objective was to evaluate the percentage of bone-to-implant contact, interproximal soft tissue height, location of the junctional epithelium, and length of connective tissue contact to abutment and/or implant, for the 2 different distances. RESULTS:: Results showed that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for interimplant distances of 4 or 3 mm. In addition, the secondary objective parameters also demonstrated similar results between the 2 interimplant distances. CONCLUSION:: This study showed that interimplant bone levels can usually be maintained at similar levels for 4- and 3-mm distances during at least 2 months.

BACKGROUND: The purpose of this study was to assess the effect of inter-implant distance on interproximal bone utilizing platform switching. Analysis of interproximal bone usually depends on traditional two-dimensional radiographic assessment. Although there has been increased reliability of current techniques, there has been an inability to track bone level changes over time and in three dimensions. Micro-CT has provided three-dimensional imaging that can be used in conjunction with traditional two-dimensional radiographic techniques. METHODS: This study was performed on 24 female minipigs. Twelve animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 2 mm apart creating a split mouth design. Twelve other animals received three implants with an inter-implant distance of 3 mm on one side of the mandible and another three implants on the contra-lateral side, where the implants were placed 4 mm apart creating a split mouth design too. The quantitative evaluation was performed comparatively on radiographs taken at t 0 (immediately after implantation) and at t 8 weeks (after termination). The samples were scanned by micro-computed tomography (muCT) to quantify the first bone to implant contact (fBIC) and bone volume/total volume (BV/TV). Mixed model regressions using the nonparametric Brunner-Langer method were used to determine the effect of inter-implant distance on the measured outcomes. RESULTS: The change in bone level was determined using radiography and its mean was 0.05 mm for an inter-implant distance of 3 and 0.00 mm for a 2 mm distance (P = 0.7268). The mean of this outcome was 0.18 mm for the 3 mm and for 4 mm inter-implant distance (P = 0.9500). Micro-computed tomography showed that the fBIC was always located above the reference, 0.27 and 0.20 mm for the comparison of 2-3 mm (P = 0.4622) and 0.49 and 0.34 mm for the inter-implant distance of 3 and 4 mm (P = 0.1699). BV/TV inside the defined parallelepipedic masks reached 82.38% for the 2 mm inter-implant distance and 85.00% for 3 mm, P = 0.8432. For the comparison of the 3-4 mm inter-implant distance, the means were 84.69% and 84.38%, respectively, P = 0.8401. Non-inferiority tests for the smaller inter-implant distances for both comparisons showed similar differences and similar tolerance ranges. CONCLUSION: The effect of a smaller interproximal distances between implants on bone level, fBIC and BV/TV assessed by two convergent investigation methods, radiology and muCT, was similar to that of larger distances. Implants can potentially be placed 2 mm apart instead of 3 mm and 3 mm apart instead of 4 mm when platform switching is utilized. Further research with a conventional platform is warranted.

Introduction: Low wattage laser use in periodontal therapy is well documented, but effects on bone repair are not understood. We used a low wattage laser to examine the effects of laser treatment on bone healing in a rabbit cranial defect bone-healing model. Materials and Methods: Bone defects were created in rabbit parietal bones using a trephine in 16 rabbits (5mm in diameter, 1/2 skull thickness defects), and 4 were created in the two parietal bones of each rabbit. One defect was untreated (control), and the remaining three were treated for 15, 30 and 45 seconds using a Navigator 810 nm diode laser (Ivoclar Vivadent, Inc) with non-initiated tip at 1.0 watts in continuous mode. Defects were evaluated using micro computed tomo-graphy (microCT) and hard tissue histomorphometry at 2 and 4 weeks. Results: Treatment was observed to increase levels of coagulation at the wound sites. 2-week analysis was inconclusive, but 4-week results were significant. Histomorphometric analysis of the 15, 30, and 45-second treatment groups versus the control group showed a 21% increase in bone formation, which was significant at a p <= 0.05 level. Treated sites showed higher osteoblastic activity than untreated sites. Increase in bone formation may be related to stabilize coagulation and lower amounts of wound contracture at treated sites. Conclusion: Low wattage laser treatment of craniofacial bone defects suggested significant increases in bone formation versus untreated sites

Background: It has been demonstrated that implants restored according to a platform-switching concept (implant-abutment interface with a reduced diameter relative to the implant platform diameter) present less crestal bone loss than implants restored with a standard protocol. When implants are placed adjacent to one another, this bone loss may combine through overlapping, thereby causing loss of the interproximal height of bone and papilla. . The objective of the present study consisted on comparing the effects of two interimplant distances (3 mm and 2 mm) on bone maintenance when bone level implants with platform-switching were used. Methods: This study evaluated marginal bone level preservation and soft tissue quality around a bone level implant, following two months of healing in minipig mandibles. The primary objective of this study was to evaluate histologically and histomorphometrically the affect that an implant design with a horizontally displaced implant-abutment junction has on the height of the crest of bone, between adjacent implants separated by two different distances: 3 mm and 2 mm. Results: Results showed that the interproximal bone loss measured from the edge of the implant platform to the bone crest was not different for inter-implant distances of 3 or 2mm. The horizontal position of the bone relative to the microgap on platform level (horizontal component of crestal bone loss) was 0.57 mm +/- 0.51 above the platform eight weeks after implantation for the 3 mm inter-implant distance and 0.31 +/- 0.3 mm for the 2 mm inter-implant distance. Conclusions: This study showed that inter-implant bone levels can be maintained at similar levels for 3 mm and 2 mm distances. The horizontally displaced implant abutment junction provided for a more coronal position of the first point of bone to implant contact. The study revealed a smaller horizontal component at the crest of bone than has been reported for non-horizontally displaced implant abutment junctions

While the original Branemark implant protocol has continued to evolve, the avoidance of implant loading during osseointegration remains a prerequisite with all implant systems. Immediately loaded transitional implants have recently been developed to support the fabrication of a fixed provisional prosthesis that provides implant patients with improved aesthetics and function during the osseointegration period. In this manner, osseointegration can occur free from prosthetic and transmucosal loads. This article describes the use of transitional implants and presents a classification of three different case types