Influence of the implant design on osseointegration and crestal bone resorption of immediate implants: A histomorphometric study in dogs

Purpose: The aim of this study was to evaluate bone-to-implant contact after immediate implant placement at different levels in relation to crestal bone in American foxhound dogs. Materials and methods: The mandibular second, third, and fourth premolars of six American foxhound dogs were extracted bilaterally. Randomly, three immediate implants were placed in the hemimandible of each dog at the bone crest (control group) or 2 mm subcrestally (test group). Three dogs were allowed an 8-week healing period; the other three were left a 12-week healing period. After healing periods, histomorphometric analyses of the specimens were carried out to measure BIC values and bone remodeling. Results: All implants healed uneventfully and were available for histological analysis. The total BIC mean values were 44.52% (±8.67) and 39.50% (±9.25) at 8 and 12 weeks, respectively, for the control group, and 47.33% (±5.23) and 53.85% (±4.21) at 8 and 12 weeks after healing for the test group, respectively. There was observed less bone resorption in the group of implants placed subcrestally. Conclusion: Our findings suggest that less resorption may be expected when implants are inserted 2 mm subcrestally. Moreover, higher BIC values in the group of subcrestal implants were found.