Predictors of dental implant survival.

Purpose: To summarize dental implant survival rates under a variety of clinical conditions and identify prognostic variables associated with implant survival.

Materials/methods: The articles reviewed in this paper were designed as retrospective cohort studies and composed of three subject cohorts having implants placed between 1992 and 2003. The prognostic variables were categorized as demographic/health status, anatomic, implant-specific, prosthetic, and perioperative/operative. The primary outcome variable was duration of implant survival. Kaplan-Meier methods were used to estimate implant survival rates. Multivariate Cox proportional hazards models were used to identify prognostic variables. RESULTS-During the study interval, 921 subjects had 2996 implants placed. Implant survival rates at one year ranged from 90.3 percent for immediate-load implants to 96.2 percent for implants inserted into grafted sinuses. The five-year survivals ranged from 87.9 percent (sinus graft cases) to 91.2 percent (all implants). Frequently cited prognostic variables included tobacco use and implant staging. Other prognostic variables identified included implant length, well size, implant coating, and timing of implant placement relative to tooth extraction.

Conclusion: Using implants to replace missing teeth is a predictable procedure with five-year survival rates approximating 90 percent. Some of the prognostic variables identified in these studies are under the control, at least to some degree, of the clinician and may be manipulated to enhance implant survival.