An evaluation of replacement rates for posterior resin-based composite and amalgam restorations in U.S. Navy and marine corps recruits.

Background: Restoration replacement is a clinical concern that has not been studied among military personnel. The authors determined the prevalence of placement of posterior amalgam and resin-based composite restorations and the incidence of replacement among U.S. Navy and Marine Corps personnel.

Methods: The authors analyzed dental records from 2,780 personnel to determine the relative risk of replacement for initially sound restorations during subjects' first years of military service.

Results: At the initial examination, 964 (15.2 percent) of amalgam restorations and 199 (17.4 percent) of resin-based composite restorations required re-treatment. Of those judged clinically acceptable, 14.2 percent of amalgam and 16.7 percent of resin-based composite restorations required replacement during the observation period. The authors found significant increases in replacement rates for resin-based composite restorations compared with amalgam restorations for replacement due to all causes (adjusted hazard ratio, 1.28; P < .05), as well as for replacement due to restoration failure (adjusted hazard ratio, 1.64; P < .01).

Conclusions: About 30 percent of posterior restorations required replacement, either at the initial examination or during the subjects' first years of military service. In a young military population, significantly more resin-based composite restorations in place at the initial examination will require replacement than will amalgam restorations. Multi-surface restorations had higher rates of replacement than did one-surface restorations, and subjects at high caries risk experienced significantly higher replacement rates than did those at low caries risk.

Clinical Implications: The number of surfaces restored and subjects' caries risk status may influence the longevity of resin-based composite and amalgam restorations.