Three-dimensional analysis of bone-implant contact of rough surface mini-screw implants.

摘要

Introduction. The purpose of this study was to evaluate the effects of surface modifications of mini-screw implants (MSIs) and force application on peri-bone-implant contact. Methods. Using randomized split-mouth design in 7 skeletally mature male foxhound dogs, 21 MSIs with a sand-blasted, large-grit and acid etched (SLA) surface were compared with 21 machine surfaced MSIs placed in the mandible. Twenty eight of the MSIs were immediately loaded with 200g using NiTi coil springs, and compared to unloaded controls. The percentages bone-implant contacts were measured in two zones from a distance of 6-to-24 mum and 24-to-42 mum from the MSI surface for both cortical and non-cortical bone using micro-computed tomography (muCT) with an isotropic resolution of 6 mum. Results. There was 100% clinical success rate for SLA surfaced MSIs, compared to the 95% for machine surfaced MSIs. Mean insertion torque was higher for SLA surfaced MSIs (39 Ncm) compared to machine surfaced MSIs (42 Ncm), but was not statistically significance (p = .875). Peri-bone-implant contact was significantly higher (p < .05) for the loaded SLA surfaced MSIs than machine surfaced MSIs. Peri-bone-implant contact ratios assessed by muCT demonstrated higher overall percentages in the SLA surfaced MSIs in both cortical and non-cortical segments. SLA surfaced MSIs under force load also demonstrated statistically significant differences in implied bone-implant contact compared to machine surfaced MSIs. BV/TV ratios evaluated a distance from 6-to-24 mum were significantly less compared to ratios from 24-to-42 mum. Conclusion. SLA surfaced MSIs demonstrated 100% success rate, compared to the 95% for machine surfaced MSIs. Peri-bone-implant contact was significantly higher for SLA surfaced MSIs than machine surfaced MSIs. Insertion torque was higher for SLA surfaced MSIs, but the differences not statistically significant. Force application demonstrated a significant increase in peri-bone-implant contact for SLA surfaced MSIs.