Efficacy of threaded hydroxyapatite-coated implants placed in the posterior mandible in support of fixed prostheses.

A data subset from an ongoing prospective multicenter clinical study of threaded hydroxyapatite-coated implants was evaluated to assess safety and efficacy of the implants when used to support fixed prostheses in the posterior mandible. Observations were recorded before surgery, at first-stage surgery, at second-stage surgery, at loading, and at quarterly postrestoration prophylactic exams and annual comprehensive patient visits. Implant failure criteria included mobility, radiographic evidence of bone loss greater than one-third the length of the implant or peri-implant radiolucency, fracture, exfoliation, removal for any reason, and patient reported pain upon palpation. Soft tissue indices were monitored as part of the study. Postrestoration implant performance was analyzed using life-table methodology. From the 2,062 implants restored in 720 patients in the parent study, a total of 423 implants in 195 patients were included in the posterior mandibular data subset. Thirteen implants failed at or before second-stage surgery for a surgical success rate of 96.9 percent. Prosthodontics was completed, and one or more postrestoration annual follow-up visits occurred for 314 implants as of the interim analysis cutoff date. Fourteen implants failed during an observation period extending up to 62 months after completion of prosthodontic treatment. One failed implant was removed, whereas the 13 remaining implants are functional despite having been identified as failures under the protocol criteria. The Cutler-Ederer life table success rate after 5 years was 92.2 percent. Results of this investigation suggest that threaded hydroxyapatite-coated implants are effective when placed in posterior mandibular regions in support of fixed prostheses.