Integration of fluoridated implants in onlay autogenous bone grafts - an experimental study in the rabbit tibia

Introduction: Bone augmentation before treatment with endosseous implants is a common procedure for rehabilitation of the edentulous jaw. Both machined and surface modified implants have been used in one-stage and two-stage surgery protocols with varying results and survival rates. The influence of surface modification on the integration of implants has been documented in both non-grafted and grafted bone. The aim of this study was to compare the integration and stability of surface modified fluoridated vs. machined implants when placed simultaneously with an onlay bone graft.

Material and methods: Eight rabbits were used in this study. A disc shaped bone graft was harvested from each side of the sagittal suture of the calvarial bone and fixed bi-cortically to the proximal tibial metaphysis by means of a dental implant, 9 mm long and 3.5 mm in diameter with a smooth machined surface as control and a blasted, fluoridated surface as test. Test and control sides were randomised. After a healing time of 8 weeks, the rabbits were sacrificed and the implants were removed en block for light microscopic analysis. Bone to implant contact (BIC) was registered as well as the amount of bone filling a rectangle indicating a region of interest (ROI) in the grafted area. Resonance frequency analysis (RFA) was conducted both at the time of surgery and at the end of the study.

Results: Our results showed statistically significant differences in BIC within the grafted area and the total bone to implant contact between the test and control sides in favour of the surface modified implants. The bone area filling the threads within a region of interest showed no statistically significant difference between the test and control sides. RFA showed higher implant stability with significant differences at the time of sacrifice in favour of the fluoridated implants.

Conclusion: Surface modified fluoridated implants showed a higher degree of osseointegration and stability in onlay bone grafts compared with control implants with machined surface texture.