Comparative Evaluation of Fracture Resistance of Maxillary Premolars with Class II Cavities Restored with Glass Hybrid Restorative System and Nanohybrid Composite Resin: An In-vitro Study

Introduction: Maxillary premolars are the most susceptible teeth to fracture if both marginal ridges are compromised. Composite restorations have performed remarkably in restoring the marginal ridges. However, it has certain disadvantages, thus to overcome this, modified glass ionomer based restorative materials with improved mechanical properties were introduced. Aim: To compare and evaluate the fracture resistance of maxillary premolars with class II Mesio-Occluso-Distal (MOD) cavities which received Glass hybrid restorative system and Nanohybrid Composite resin. Materials and Methods: The present study was an in-vitro study at KM Shah Dental College and Hospital, Vadodara, Gujarat from December 2019 to June 2020, on 30 Extracted Maxillary premolars were selected. Total samples were divided into group A (n=15) restored by glass hybrid restorative system and group B (n=15) restored by nanohybrid composite resin. Standardised class II MOD Cavity preparation was done in all the samples. The samples were subjected to a thermocycling procedure, and a universal testing machine measured the fracture resistance. Data obtained from all the samples was analysed by Independent sample t-test with a p-value set at less than 0.05. Results: In group A, mean fracture resistance (at mean force 947.07 +/- 236.41) was found to be greater than in Group B. However, the difference among the groups was not statistically significant with a p-value of 0.555. Conclusion: Glass Hybrid restorative system showed better fracture resistance than Nanohybrid Composite Resin in maxillary premolars with class II MOD Cavities.