The effect of bi-cortical anchorages on implant primary stability

Objectives: This study was to evaluate the influence of mono- and bi- cortical bone-implant engagements on the stability of immediate loading implants under controlled loadings. Material and Methods: Implants were placed under mono-cortical and bi-cortical bone engagement conditions in fresh costal bones of cattle. Loads of 25N and 50N were applied on the implants respectively. The implant stability quotient (ISQ) was measured before loading, after 1800-cycli loading and 3600-cycli loading respectively. Results: Under the mono-cortical bone engagement condition, there was no difference in ISQ value between pre-loading and 1800-cycli loading for the 25N load.(P>0.05), but that of 3600-cycli loading decreased significantly(P<0.05). For the 50N load, the ISQ value of 1800-cycli and 3600-cycli loading both decreased significantly.(P<0.05). Under the bi-cortical bone engagement condition, there were no difference in ISQ value between pre-loading and 1800-cycli loading.(P>0.05)for both loads, but the ISQ value of the 3600-cycli loading decreased significantly (P<0.05). Conclusion: Value and frequency of the load would affect the stability of immediate loading implants. The increase of cortical bone anchorages would benefit the primary stability of immediate loading implant.