Comparative evaluation of three types of fiber orientation techniques on fracture resistance of endodontically treated premolars restored with composite resin: An in vitro study

A new technique of fiber reinforcement (horizontal + base fiber [HBF]) in the restoration of endodontically treated teeth (ETT) with composite resin was proposed. This study aims to compare three different types of fiber orientation techniques on fracture resistance of ETT. Sixty intact extracted human maxillary premolars were assigned to five groups (n = 12). Group 1 intact teeth (control). The teeth in Groups 2–5 received endodontic treatment and a MOD cavity preparation and restored with composite resin with polyethylene fiber at different positions. Group 2: No fiber group (NF), Group 3: Occlusal fiber group (OF), Group 4: Horizontal fiber group (HF), and Group 5: HBF group. After thermocycling, the specimens were loaded using a universal testing machine until fracture and the fracture patterns were analyzed. The data were analyzed statistically using analysis of variance with Tukey’s post hoc test (fracture load) and Chi-square test (fracture patterns). Fiber-reinforced groups (OF, HF, HBF) showed significantly higher fracture resistance compared to NF group (P < 0.05). No significant differences in fracture resistance were observed between (a) fiber-reinforced groups (OF, HF, HBF) and intact teeth (P > 0.05) (b) amongst the fiber-reinforced groups (OF, HF, HBF) (P > 0.05). With regard to fracture patterns, no significant differences were observed between the study groups (P > 0.05). Restoring ETT with different techniques of fiber reinforcement resulted in the improvement of the fracture resistance comparable to that of intact teeth. The newly proposed technique of fiber insertion might be considered as an alternative to earlier techniques for the reinforcement of ETT.