No remarkable complications were found during the healing period. At sacrifice, all 18 implants fixed after 9 months were considered successfully integrated at the time of the removal and none showed any mobility or signal of infection at sacrifice. There was no difference in the healing between animals who had the implants immediately removed after installation, and animal whose implants were removed 9 months later of installation.

The mean and standard deviation of removal torque are illustrated in Tables 1 and 2 for both experimental specimens. The removal torque values increased after 9 months, with significant differences between IR and after 9M specimens.

Each third of the peri-implant bone was evaluated and showed not representative difference in the bone conditions for each experimental specimen separately (9M and IR) (Figs. 4 and 5). Removal torque did not alter the characteristics of mature bone and the healing process; thereby, did not cause significant damage in the peri-implant bone. After surgical trauma, it was possible to notice inflammatory process, which blood cells in the alveolar bone of IR specimens. At the 9M specimens, mature bone was evident, as well as presence of fibrous connective tissue without evidence of inflammatory infiltrate. A vital bone with many osteocytic lacunae was observed on the grooving of the internal wall of peri-implant bone. Many capillaries were present, and a rim of osteoblasts was observed on the bone margins. Natural inflammatory and bloody cells were visible only in IR specimens. As well as only in the IR specimens were observed small fractures and rounding in the bone grooving caused by implant trephine and removal torque. At 9M experimental condition, bone grooving presented clear contours, without rounding or fractures. In both experimental specimens, there was no evidence of bone formation particularly at tissue around the peri-implant bone surface. Only in the last third (apical) was possible to identify some bone fragments, probably caused by implantation procedure.