Osseointegration of dental implants installed without mechanical engagement: a histometric analysis in dogs

Abstract

Objectives: The purpose of this study was to elucidate the healing pattern of sand-blasted, large grid, acid-etched (SLA)-surfaced implants at two healing periods in a model that represents loosened implants (LIs) installed without mechanical engagement.Materials and methods: Five mongrel dogs were used, in which 20 dental implants were prepared. The implants were divided into two groups according to the absence or presence of initial mechanical engagement: loosened implants (LIs) and control, respectively. An oversized drill was used to prepare the implant area for the LI group. The implants were allowed to heal for 4 or 8 weeks. After the healing period, the experimental animals were sacrificed and block sections were obtained for histological analysis and histometric measurements.Results: All implants were in intimate contact with the host bone and were without any inflammation after both 4 and 8 weeks of healing. While the mean amount of bone-to-implant contact (BIC) was constant in the control group, it tended to increase in the LI group with increasing healing period. However, neither BIC nor bone density differed significantly between the groups or with the healing period.Conclusion: From the results of the study, it can be conjectured that the submerged and unloaded SLA-surfaced implants could result in successful osseointegration, even if the mechanical engagement was not obtained at placement of the implants.