Different configuration of socket shield technique in peri-implant bone preservation: An experimental study in dog mandible

Thirty-six dental implants were installed in 6 dogs. The clinical crowns of teeth P3, P4 and M1 were beheaded. Afterwards, the roots were worn down 2-3 mm in apical direction until they were located at crestal level. Posterior implant beds were prepared in the center of the roots passing by 3 mm apically forming 6 groups in accordance to the remaining root thickness. Radiography of the crestal bone level was performed on day 0 and after 12 weeks. Histomorphometric analyses of the specimens were carried out to measure the crestal bone level, the bone to implant contact and the buccal and lingual bone thickness at the implant shoulder portion. Correlations between groups were analyzed through nonparametric Friedman test, statistical significance was set as p < 0.05. All 36 implants were osseointegrated, but 3 samples showed a clinical inflammatory reaction and some radicular fragments presented a small resorption process. On the buccal and lingual side, the radicular fragment was attached to the buccal bone plate by a physiologic periodontal ligament. In the areas where there was space between the implant and the fragment, newly formed bone was demonstrated directly on the implant surface. Within the limitations of an animal pilot study, root-T belt technique may be beneficial in preserving and protecting the bundle bone and preservation of soft tissues. If the thickness of the buccal bone is 3 mm, and the thickness of the remaining root fragment is 2 mm, the socket shield technique is more predictable and the bone contours can be maintained.