Osseointegration around implants placed in osseous circunferencial defects treated mediately or imediately with Bio-Oss, hydroxyapatite and autogenous bone. a histological, histometric, micro-tomographic and RFA in dogs

Abstract

Several materials and techniques have been described attempting to increase the implants treatment previsibility, in post extraction alveolus, in order to fill the space around the implant and favor osseointegration process. The autogenous or allogenous bone grafts obtainment to fill these defects, the use of bone's substitutes such as hydroxyapatite, bioglass or bovine bone (Bio-Oss), or even various combinations showed to be viable treatment modalities. Although the majority of techniques promote the osseous filling of the defect, providing a better alveolar and soft tissue contour, it doesn't guarantee that an efficient osseointegration have been occurred. The aim of the present study is to evaluate the Bio-Oss efficacy on osseointegration and implants stability, placed at just made osseous defects besides to compare it with other bone substitutes. For this study, six young male dogs will be used. The surgical period will be divided into three steps: the first will be the bilateral mandible premolars extraction. In a second surgery, four bone defects at alveolar ridge will be made, at one side only. These defects will be treated with Bio-Oss, Straumann Bone Ceramic, autogenous bone or clot. After eight weeks, other four defects will be surgically created in the opposite side, and filled with the same materials described. In the same procedure, four implants will be placed in each sides. The implants primary stability will be measured by bone-implant resonance frequency analysis, reading the implant stability quotient, registered by Osstell mentor® (Integration Diagnostics AB, Gotemburg, Sweden), at the implants placement moment and at the sacrifice period. After ten weeks, the animals will be sacrificed by anesthetic overdose. The morphometric measurements will be done considering the bone-implant contact. The results obtained will be processed by variance analysis (ANOVA). (AU)