A two-site clinical study of hydroxyapatite-coated cylindrical titanium alloy implants was undertaken to evaluate their efficacy. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly postrestoration prophylactic examinations and annual comprehensive patient visits. Implant failure criteria included mobility, peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain on palpation. Soft tissue indices were monitored as part of the study. Postrestoration implant performance was analyzed using life table methodology. From the 316 implants restored in 154 patients, 11 implants in 8 patients failed before prosthetic attachment, for a surgical success rate of 96.4 percent. Four implants failed during an observation period extending up to 85 months after completion of prosthetic treatment. The Cutler-Ederer life table success rate after 6 years was 97.8 percent. No significant adverse events were reported during the observation period. Results of this investigation suggest that hydroxyapatite-coated cylindrical titanium alloy implants are an effective treatment modality.