Abstract
AIM: This study aims to analyze the depth of penetration of two different adhesives using Confocal Laser Scanning Microscope in Class I amalgam restorations replaced with composite restorations. SUBJECTS AND METHODS: Eighty freshly extracted human premolars were selected for the study. Samples were randomly divided into four groups (n = 20). Class I cavities were prepared for composite resin restorations the adhesive used in Group Ia: Tetric N-Bond and Group Ib: Tetric N-Bond Universal. For Group II and Group III: Samples were first restored with silver amalgam and removed after 1 year followed by composite resin restoration: Adhesive used in Group II: Tetric N-Bond and Group III: Tetric N-Bond Universal. While using the adhesives each time, they were labeled with 0.1% Rhodamine B dye. After restoring the samples using Te-Econom Plus, they were sectioned with a microtome precision saw. CLSM was used to determine the thickness of the hybrid layer and the number of resin tags. RESULTS: Higher values of thickness of hybrid layer and number of resin tags were observed in the control group as compared to the experimental groups. CONCLUSIONS: A significantly thicker hybrid layer and higher number of resin tags were obtained when a total-etch system was used for replacing old amalgam restoration with composite resin.