COMPARISON OF FRACTURE RESISTANCE OF ENDODONTICALLY TREATED CLASS II PREMOLAR TEETH RESTORED WITH DIFFERENT COMPOSITE RESTORATIONS: AN INVITRO STUDY

Aims: The present study aimed to compare fracture resistance of endodontically treated class II premolar teeth restored with different composite restorations. . Methodology: Sixty intact human premolars were selected for this study. All teeth received disto-occlusal preparation such that the buccolingual width was 3mm, mesiodistal width was 2mm and depth of the cavity was 4mm. A conservative endodontic access was done. The biomechanical preparation was done using hyflex CM rotary files upto apical size 30 with 6% taper. After preparation, canals were obturated with gutta percha using single cone technique. All teeth were etched with 37% phosphoric acid for 15seconds and washed with water for 15 seconds. The teeth were randomly divided into 6 groups (n=10 in each group) according to the type of the restorative material that was used Group A: Filtek P60 Group B: 3M ESPE Filtek Z250 XT Group C: Filtek bulkfill Group D: Tetric N-Ceram Bulkfill (Ivoclar) Group E: 3M Filtek Supreme Flowable Restorative underneath Filtek bulkfill Group F: Tetric N-Flow Bulkfill underneath Tetric N-Ceram bulkfill. All specimens were stored in an incubator at 37º C for 1week. The samples were subjected to universal testing machine at to determine fracture resistance. Results: The highest fracture resistance was seen in teeth restored with 3M Filtek Supreme Flowable Restorative underneath Filtek bulkfill next by Tetric N-Flow Bulkfill underneath Tetric N-Ceram bulkfill, followed by Filtek bulkfill, Tetric N-Ceram Bulkfill, Filtek Z250 XT and least with Filtek P60. The statistical significance of these variations yielded a p-value of <0.001, indicating a highly significant difference among the groups. Conclusion: This study concluded that, flowable composite underneath bulkfill improves fracture resistance of teeth when compared to only bulkfill. Highest fracture resistance is seen in Filtek Supreme Flowable Restorative underneath Filtek bulkfill, Tetric N-Flow Bulkfill underneath Tetric N-Ceram bulkfill followed by Filtek bulkfill, Tetric N-Ceram Bulkfill, Filtek Z250 XT, Filtek P60.