Reosseointegration of mechanically disintegrated implants in dogs: mechanical and histometric analyses

Objectives: This study evaluated the reosseointegration of implants that had been reinserted following the mechanical disintegration of immature osseointegration in dogs.

Materials and methods: Rotationally mobile implants were installed into an oversized drill space in five canine mandibles. After a healing period of 4 weeks, the immature osseointegration of the implant was intentionally disintegrated by the application of a mechanical countertorque and then reinserted at the same site (experimental group); in the control group, the mobile implant remained submerged without any surgical intervention. The animals were euthanized 4 weeks after the disruption of osseointegration. Changes in the implant stability quotient (ISQ) and Periotest value (PTV) were analyzed, and the bone-implant contact (%) was measured histometrically.

Results: All experimental and control sites showed successful mechanical stability at 8-week healing period. The mean ISQ was significantly higher in the experimental group than in the control group at 8 weeks (P < 0.01). In histology, immature woven-bone that bridged between the parent bone and the pre-existing residual bone on implant surface could be observed in experimental sites. The mean bone-implant contact was significantly higher in the experimental group than in the control group (P < 0.05).

Conclusion: Within the limitation of the small sample used in this study, it is concluded that following the mechanical disruption of osseointegration, an implant can be successfully reosseointegrated with unloaded and submerged healing for a certain period.