ABSTRACT
Objective:To study the effects of fluor-hydroxyapatite (FHA) coating titanium alloy on the osseointegration and peri-implantitis of orthodontic micro-implant.Methods:Titanium of FHA alloy (FHA group) and titanium alloy(control group) orthodontic micro-implants were respectively planted into buccal alveolar bone in mandibular premolar area of rabbits.Scanning electron microscope was used to observe the osseointegration around the micro-implants.ELISA was employed to detect TNF-α in the gingival crevicular fluid around the implants.Results:The FHA-coating titanium alloy orthodontic micro-implants led to higher bone density,smaller marrow cavity,and lower TNF-α level and shorter lasting period of TNF-α over-expression than the controls (P ＜ 0.05).Conclusion:The FHA-coating titanium alloy orthodontic micro-implant has better histocompatibility and may inhibit peri-implantitis.
ABSTRACT
OBJECTIVE: The present study was aimed at an analytical formulation of the micro-implant related torque as a function of implant size, i.e. the diameter and length, screw size, and the bony resistance at the implant to bone interface. METHODS: The resistance at the implant to cancellous bone interface (S(can)) was assumed to be in the range of 1.0-2.5 MPa. Micro-implant model of Absoanchor (Dentos Inc. Daegu, Korea) was used in the course of the analysis. RESULTS: The results showed that the torque was a strong function of diameter, length, and the screw height. As the diameter increased and as the screw size decreased, the torque index decreased. However the strength index was a different function of the implant and bone factors. The whole Absoanchor implant models were within the safe region when the resistance at the implant/cancellous bone (= S(can)) was 1.0 or less. CONCLUSION: For bone with S(can) of 1.5 MPa, the cervical diameter should be greater than 1.5 mm if micro-implant models of 12 mm long are to be placed. For S(can) of 2.0 MPa, micro-implant models of larger cervical diameter than 1.5 mm were found to be safe only if the endosseous length was less than 8 mm.