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 p
atient 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, re
placement rates of three alloys applied in comparable circumstances (n
=394) are reported. Of the restorations, 214 (17.6%) were replaced dur
ing the trial period. Factors influencing the replacement rates are ge
nder, 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.