Interim clinical study report: a threaded, hydroxylapatite-coated implant--five-year post-restoration safety and efficacy.

An ongoing prospective clinical trial is being conducted at three study sites to evaluate the safety and efficacy of a threaded, hydroxylapatite-coated implant (Steri-Oss Inc., Yorba Linda, CA) in a patient population reflective of the investigators' overall population of implant candidates. The 2062 implants placed and restored among 720 patients over the five-year period up to the study interim analysis cut-off date (November, 1994) include over 600 implants and 200 patients at each study site. Mean age and sex distribution of patients were comparable among the study sites. Study design attributes included well-defined patient selection criteria, standardized study procedures, standardized measurement and observation methodology, complete data accountability, and rigorously applied implant success/failure criteria. Thirty-five implants were considered failures at exposure, and the surgical success rate was 98.3%. Of 65 implants that failed post-restoration, three were removed, while 62 remained functional and in service. The five-year post-restoration follow-up success rate, determined by means of life table methodology, was 96.0%. By region, the five-year life table success rates post-restoration were 94.3% in the anterior maxilla, 96.6% in the posterior maxilla, 97.2% in the anterior mandible, and 95.6% in the posterior mandible. Adverse events occurred in association with less than 1% of the implants placed.