Stability of implants placed simultaneously or in a delayed manner on fresh frozen onlay allografts in rabbits

Abstract

This study evaluated the stability of implants installed simultaneously and in a delayed manner in fresh frozen onlay allografts in the tibiae of rabbits. Analyses of the resonance frequency (ISQ) and removal torque were performed. The calvarium of three rabbits was used as donor site. Ten New Zealand female rabbits received four allografts of the same dimensions, two in each tibia. The tibiae were randomly allocated into the following two groups: Group 1, the tibiae that received implants after 84 days of healing, and Group 2, those who received the implants simultaneously with the grafts. Both groups were followed for 126 days. Proximal implants in each group were evaluated by resonance frequency (ISQ) on days 0 and 126, and the distal ones with removal torque on day 126. In both groups, an increase in the ISQ value of day 0-126 was observed, with a statistically significant difference (Group 1 P = 0.049 and Group 2 P = 0.021). When comparing the resonance frequency at day 0 to day 126, and the gain of stability between these days, no statistically significant difference between groups could be observed. The removal torque showed a statistically significant difference between groups 1 and 2 (P = 0.042). There was an increase in stability in groups according to the analysis of resonance frequency. Implants installed in a delayed manner in allografts showed higher shear force, according to the removal torque analysis.