reasons for retreatment of amalgam and composite restorations among the patients referring to tabriz faculty of dentistry

background and aims. retreatment of existing restorations not only requires a lot of money and time but also there is a danger of weakening tooth structure and irritating the pulp. since awareness of the reasons for the retreatment of teeth will save the teeth from possible future failure, the aim of this study was to assess the reasons for retreatment of amalgam and composite restorations in patients referring to tabriz faculty of dentistry. materials and methods. in this descriptive study, the subjects had previously received an amalgam or a composite restoration in the operative department by dental students and were judged to need retreatment in their second visit. a total of 300 defective teeth were selected by simple random sampling method. the data was collected through examination and questionnaires and analyzed using chi-square test. results. there was a statistically significant association between the type of the restorative material and the reason for retreatment (p=0.001). conclusion. although the reasons for the retreatment of amalgam and composite restorations were different, recurrent caries was the main reason for the retreatment for both restorative materials.