15-year evaluation of Class II amalgam restorations.

In a clinical trial, 1544 Class II amalgam restorations were inserted. In this study 1213 restorations were evaluated after 15 years and the reasons for replacement were registered. Attention was also paid to patient drop-out and patients' variables such as gender, filling degree, type of tooth (premolar vs molar), type of restoration (MO or DO vs MOD), jaw (upper vs lower) and the patients' operator. Furthermore, replacement rates of three alloys applied in comparable circumstances (n = 394) are reported. Of the restorations, 214 (17.6%) were replaced during the trial period. Factors influencing the replacement rates are gender, type of restoration and operator. Factors such as type of tooth and type of alloy seemed to have no influence on the replacement rates in this study.