Objective: To investigate fracture resistance and failure mode of maxillary premolars restored with resin composite endocrowns prepared using different restorative approaches in comparison to ceramic endocrowns.
Methods: Fifty sound human maxillary premolars were used in the current study. Teeth were randomly divided into five groups according to restorative approach used in fabrication of endocrowns; group I: resin composite material, group II: composite modeled with resin adhesive, group III: composite modeled with flowable composite, group IV: ceramic material and group V: intact premolars (Control group).Teeth assigned for group I, II, III and IV were endodontically treated and prepared for endocrowns with internal depth 4 mm and cervical margin 2 mm. Endocrowns were fabricated and tested for fracture resistance using universal testing machine. Failure mode was assessed under a stereomicroscope. Data were tabulated and statistically analyzed.
Results: Fracture resistance results showed no significant difference between control group (1513.37±67.77) and composite modeled with flowable composite group (1538.31±158.00), resin composite group (1434.7±117.60) and composite modeled with resin adhesive group (1396.57±83.03). Ceramic group (707.79±127.05) recorded the lowest mean values. Regarding failure mode, ceramic group recorded mainly irreparable failures while other experimental groups recorded reparable ones.
Conclusion: Resin composite endocrowns is better choice compared to ceramic ones in restoration of endodontically treated premolars. Modeling of resin composite using flowable composite and resin adhesive is considered a promising approach in restoration of endodontically treated premolars with more favorable fracture behavior than ceramic materials.