Fracture Resistance of Maxillary First Premolars with Class II Cavity Preparation that Filled with Different Restorative Materials

Background: Severely damaged teeth by caries or trauma and restored with different types of restoration have susceptibility to fracture so the teeth should be reinforced with the best biomimetic restoration to resist fracture. Objectives: To evaluate and compare the fracture resistance of large and medium size class II cavities of maxillary first premolars filled with amalgam, Equia Forte, Cention Forte, Tetric EvoCeram Bulk Fill, Tetric PowerFill Bulk Fill, everX Posterior. Also to evaluate the failure mode of each restored tooth. Materials and Methods: Class II cavities were prepared on 160 maxillary first premolars which were divided into eight groups: (1) positive control, (2) negative control, (3) amalgam filled teeth, (4) Equia Forte filled teeth, (5) Cention forte filled teeth, (6) Tetric Evoceram bulk filled teeth, (7) Tetric Powerfill bulk filled teeth, and (8) everX Posterior filled teeth. The samples were thermocycled for 5000 cycles with a temperature ranging from 5°C to 55°C. The fracture test was done by applying load with a crosshead of 1 mm/min. Results: Two-way ANOVA revealed significant differences among the groups ( P = 0.05), Tukey HSD post hoc test revealed that the high fracture resistance of everX Posterior filled teeth (1180.9059 Newton) was nearly similar to that of positive control. Conclusion: everX Posterior can be considered as dentin-replacing material to reinforce the teeth against fracture.