Comparative evaluation of the effect of adhesive restorative composite resins on the reinforcement of peri-cervical dentin: An in vitro study

BACKGROUND: Peri-cervical dentin (PCD) and its reinforcement play a crucial role in the fracture resistance of root canal-treated teeth. AIMS: The aim of this study was to compare the fracture resistance of dual-cure, nano-hybrid, and short-fiber reinforced composite resins restored PCD with conventional hybrid composite (CHC) resin restored endodontically treated mandibular premolars. SETTINGS AND DESIGN: Academic, in vitro study. MATERIALS AND METHODS: The prepared mandibular premolar samples were randomly divided into five groups of 10 each. In Group 1, teeth were left intact. The remaining 40 teeth were endodontically treated and obturated as follows: In Group 2, teeth were obturated with gutta-percha till cementoenamel junction and restored with CHC. Teeth in Groups 3, 4, and 5 were obturated to a depth of 5 mm from the cervical line and restored with dual-cure, nano-hybrid, and short-fiber reinforced composite resins, respectively. Fracture resistance was tested using a universal testing machine. STATISTICAL ANALYSIS USED: One-way analysis of variance and post hoc Tukey's test. RESULTS: Short-fiber reinforced composite resin showed a significantly higher mean fracture resistance value compared with other experimental groups. The mean fracture resistance values were obtained as Group 1 > Group 5 > Group 4 > Group 3 > Group 2. CONCLUSIONS: Reinforcement with short-fiber reinforced composite showed significantly higher fracture resistance compared with nano-hybrid and dual-cure composite resins.