Comparative Evaluation of Internal Margin Adaptation and Integrity of Class I Preparations using Two Composites: An In Vitro Study

AIM AND OBJECTIVES: The aim of this study is to evaluate the internal margin adaptation and integrity of Class 1 preparations using two composites types (bulk fill/conventional) with two placement methods (4/2 mm increments). MATERIALS AND METHODS: Class 1 preparations of 4 mm × 4 mm dimensions were made on 30 extracted human mandibular molars. They were randomly divided into three groups; among them, in Group 1 (n = 10), cavities were filled with SureFil SDR Bulk Fill, Group 2 (n = 10) cavities were filled with Filtek Bulk Fill of 4 mm increments in both groups, and in Group 3 (n = 10), cavities were filled with conventional composite Filtek Z350 with 2 mm increments. Samples were sectioned occlusogingivally. Then, dye was on internal margins, and images of each specimen were recorded using a digital camera to evaluate the marginal integrity and adaptation of restorative material to the tooth surface with image analysis software. Then, collected data were put under the statistical analysis with analysis of variance test and post hoc Tukey's test. RESULTS: There was no significant difference in overall dye penetration in bulk fill and conventional (incremental fill) composite resins; however, when dye penetration was evaluated at different locations, within enamel and mid-dentin, significantly more gap-free margins were found than at the pulpal interface. Filtek Bulk Fill and conventional composite (Filtek Z350) showed comparatively more dye penetration toward the pulpal interface compared to SDR Bulk Fill. CONCLUSION: There were no significant differences in percentage of gap-free margins between fill types for any of the composite materials. The proportions of gap-free margin were less at the pulpal interface and mid-dentin portions and enamel when filled with 4 and 2 mm increments.