Implant-supported single-tooth replacements: risk of implant and prosthesis failure.

Data from 236 patient cases of implant-supported single-tooth replacements in the maxillary anterior region were sequentially recorded and documented. The time in situ ranged from a minimum of five to a maximum of 19 years. Twenty-two implants failed during the observation period. The causes of such failure were peri-implantitis, implant fracture, and trauma. The probability of success according to the Kaplan-Meier method decreased to 0.89 over a period of 10 years. The failure rate for implants replacing lateral incisors was lower than that for implants replacing central incisors. Seventy-six cases were clinically documented for 10 years or more. In 15 cases, replacement of the prosthetic superstructure was necessary during the 10-year period. The course of therapy and clinical follow-up care is described by a multi-state distribution.