Anterior resin fillings of seven composite resin materials--two conventional, two hybrid, and three microfiller--were evaluated over a 6-year period. Extrinsic discoloration, color match, marginal discoloration, marginal adaptation, surface roughness, and recurrent caries were investigated. The individual caries increment was compared with an estimation of the expected caries risk of the individuals. The estimation was based on the net effect of microbial counts, oral hygiene, salivary flow rates, buffer values, and fermentable carbohydrate intake. The variation of the investigated factors within each resin group was too great to enable combination of the results. The individual materials are therefore presented and compared. Unacceptable color match scores after 6 years varied markedly among the brands (3.5%-79.7%). Unacceptable marginal discoloration was seen in 1.7% of the restorations, whereas unacceptable marginal adaptation varied between 13.7% and 37.3% for the brands. Recurrent caries occurred at the margins of 18.9% of the composite fillings (range, 9.3%-29.4%) during the period. The cumulative relative frequencies of replaced fillings for the materials varied between 14.8% and 55.1%. Recurrent caries was the major reason for replacement. Patients with many caries risk factors showed clearly a higher increment of caries.