Effect of loading time on marginal bone loss around hydroxyapatite-coated implants

Objectives: The objective of this study is compare the rate of marginal bone resorption around hydroxyapatite-coated implants given different loading times in order to evaluate their stability. Materials and Methods: The study was conducted retrospectively for one year, targeting 41 patients whose treatment areas were the posterior maxilla and the mandible. Osstem TS III HA (Osstem Implant Co., Busan, Korea) and Zimmer TSV-HA (Zimmer Dental, Carlsbad, CA, USA), which employ the new hydroxyapatite coating technique, were used. The patients were divided into two groups - immediate and delayed loading - and the bone level at the time of loading commencement and after one year of loading was measured using periapical radiography. Differences between the groups were evaluated using Mann-Whitney (alpha=0.05). Results: For all patients as a single group, the survival rate of the implants was 100%, and the mean marginal bone loss was 0.26 +/- 0.59 mm. In comparison of the differences by loading, mean marginal bone loss of 0.32 +/- 0.69 mm was recorded for the immediate loading group whereas the delayed loading group had mean marginal bone loss of 0.16 +/- 0.42 mm. However, the difference was not significant (P>0.05). Conclusion: Within the limited observation period of one year, predictable survival rates can be expected when using immediately loaded hydroxyapatite-coated implants.