Comparison of fracture resistance of endodontically treated teeth with MOD cavity using different techniques of fiber insertion

Objectives: The purpose of this study was to evaluate the effect of fiber by using different techniques on fracture resistance of endodontically treated molars with mesio-occlusal-distal (MOD) cavities. Materials and Methods: Forty extracted human molars were randomly assigned to four groups (n = 10). Teeth in Groups 2-4 received root canal treatment and a MOD cavity preparation. Group 1 served as control. Group 2 was restored with composite resin. In Group 3, the fiber was inserted into the cavities in buccal to lingual direction by coating the occlusal one-third of the buccal wall to the occlusal one-third of the lingual wall, and lastly, the teeth were restored with composite resin. In Group 4, the flowable resin was coated inside the cavities with the fiber, as Group 3 was before restoring teeth with composite resin. Compressive loading of the teeth was performed at a cross-head speed of 0.5 mm/min. Data were analyzed using one-way ANOVA and Tukey post-hoc tests. Results: Fracture resistance values of all the groups were compared; the differences between Groups 2 and 3 or Groups 2 and 4 were found to be statistically significant. Conclusions: As a result, use of the fiber under composite resin with a flowable resin increased fracture strength to MOD cavities.