Unclear association between membrane and graft augmentation of implant recipient sites and failure rates

Abstract

Summary Subjects All of the partially edentulous patients (660) treated with0689 Branemark implants in the departments of periodontology and prosthodontics at the Catholic University of Leuven between December 1982 and June 1998 were included in the study. The patients were followed up until June 1999 (1 to 16.5 years, with a mean follow-up duration of 5.5 years). There were 248 males and 412 females; ages ranged from 15 to 83 years with a mean of 50.5. A total of 1956 implants with different thread profiles were placed: 270 were intended to support single crowns and 1686 to serve for fixed partial prostheses. Medical problems, bone dehiscence at the time of installation, and use (in 170 sites) of membranes and/or autologous bone grafts or xenografts were not exclusion criteria. Exposure The relationship between failure rates and several 0689 prognostic variables was analyzed. Tested predictors included patient's sex and age; implant length and location (anterior, posterior, maxilla, mandible); splinting (subsequent single crowns vs fixed partial dentures); prosthetic connection with natural teeth; use of membranes and/or grafts; implant thread profile; number of implants and prostheses per patient; and number of implants supporting each prosthesis. Main outcome measure Cumulative failure rates, estimated by life table analysis,0689 served as the main outcome measure. Mobility, radiolucency, pain, infection, or fracture identified implant failure. Main results Higher implant failure rates were significantly associated 0689 with different variables, including (1) use of membranes and/or grafts (estimated hazard rate: 4.2 times the standard procedure; 95% confidence interval = 1.8; 9.6) and (2) short implants (decreasing length was associated with an increase in the hazard rate: estimated survival rate for implants was 81.5% for implants less than 10 mm long, 91% for implants 10 to 13 mm long, and 94.6% for longer implants).