Purpose : To evaluate the clinical and radiographic success rates of pulpotomized (formocresol) primary molar teeth restored with a resin-based composite (TPH) or a polyacid-modified resin composite (Dyract AP) over a 2-year period. Methods: 100 composite and 100 compomer restorations were placed over pulpotomized teeth by two clinicians in 84 patients. Two other calibrated clinicians evaluated the restorations using the modified USPHS/Ryge criteria observing the following characteristics: marginal discoloration, marginal adaptation, wear/anatomic form, enamel loss and caries. Mann Whitney U test, Friedman test and Wilcoxon signed ranks tests were used for statistical analysis (P = 0.05). Results: At 24 months, 80 composite and 72 compomer restorations were available for evaluations. Except for baseline, compomer restorations showed significantly more marginal discoloration (P = 0.001) and marginal disintegrity (P = 0.001) than did the resin composite. Compomer restorations demonstrated a significant increase in minor enamel cracks along restoration margins over time (P = 0.001), but no chipping or loss of enamel was detected. Caries was observed only in 2.8% of compomer restorations and was restricted to restoration margins. 2% of composite and 17% of compomer restoration-treated teeth were extracted due to radiographic evidence of failure. Pathological root resorption patterns observed beneath failed compomer restorations were strongly suggestive of coronal microleakage.