Histologic Evaluation of Early Human Bone Response to Different Implant Surfaces

Background: Studies have demonstrated that roughened dental implant surfaces show firmer bone fixation and an increased percentage of bone‐to‐implant contact (BIC%) compared to commercially pure titanium‐surface (machined) implants. Therefore, the purpose of this study was to evaluate the influence of implant‐surface topography on human bone tissue after 2 months of unloaded healing. Methods: Fourteen subjects with a mean age of 46.87 ± 9.45 years received two microimplants each (2.5 mm in diameter and 6 mm in length), one test (sandblasted acid‐etched surface) and one control (machined surface), either in the mandible or in the maxilla. After a healing period of 2 months, the microimplants and surrounding tissues were removed with a trephine bur and prepared for histologic analysis. Results: All microimplants, except for one of the controls, were clinically stable after the healing period. Histometric evaluation indicated that the mean BIC% was 23.08% ± 11.95% and 42.83% ± 9.80% for machined and rough microimplant surfaces, respectively ( P = 0.0005). The bone area within the threads was also higher for sandblasted‐surface implants ( P = 0.0005). The mean percentage of bone density did not differ between the two groups ( P = 0.578). Conclusion: Data from the present histological study suggest that the sandblasted acid‐etched implant provides a better human bone tissue response than machined implants under unloaded conditions after a healing period of 2 months.