An In-vitro Evaluation of Fracture Resistance of Pulpotomised Permanent Teeth Restored with Different Aesthetic Restorative Materials

Introduction: One of the fundamental goals of modern dentistry, centered around the ideology of minimally invasive dentistry, is to maintain tooth pulp viability. The dental pulp has the capacity for repair, depending on the intensity of damage and the level of pulp inflammation. All attempts are made to preserve the vitality of the radicular pulp. Pulpotomy has been reinvestigated as a definitive therapeutic option for mature permanent teeth with extensive carious lesions. Furthermore, Class II Mesio-OcclusoDistal (MOD) cavity preparation undergoing pulpotomy reduces the teeth’s fracture resistance. Aim: To evaluate and compare the fracture resistance of pulpotomised premolars treated with calcium silicate materials, such as Mineral Trioxide Aggregate (MTA) or Biodentine (BD), in Class II MOD cavities restored using Cention-N and nanohybrid composite. Materials and Methods: An in-vitro study was conducted in the Department of Conservative Dentistry and Endodontics at Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India, from November 2023 to December 2023. A total of 55 extracted maxillary premolars were collected, embedded in acrylic resin molds, and divided into five groups of 11 teeth each. Group 1: Intact teeth, Group 2: Standardised Class II MOD cavities were prepared, coronal pulpotomy was performed, and teeth were restored with MTA. After the complete setting of MTA, a Glass Ionomer Cement (GIC) base was placed, followed by restoration with a nanohybrid composite, Group 3: Similar procedure as Group 2, but with MTA as the capping material and restored with Cention-N, Group 4: Similar procedure as Group 2, but with BD as the capping material and restored with a nanohybrid composite, Group 5: Similar procedure as Group 2, but with BD as the capping material and restored with Cention-N. Specimens were subjected to a fracture resistance test using a Universal Testing Machine (UTM). The load at which restorations fractured was recorded in Newtons (N), and the obtained data were statistically analysed using One-way Analysis of Variance (ANOVA) and post-hoc tests. Data were considered significant if p≤0.05. Results: Intact teeth (1273.64 N) had the highest mean fracture resistance compared to other groups. Group 5 (973.64 N) showed the highest mean fracture resistance, followed by Group 3 (895.45 N), Group 4 (700 N), and Group 2 (633.64 N). The differences in fracture resistance were statistically significant (p<0.05). Conclusion: The present in-vitro study found that intact teeth had the highest fracture resistance. Among the experimental groups, pulpotomised premolars restored with BD and Cention-N showed significantly greater fracture resistance. In contrast, restorations using MTA and nanohybrid composites exhibited lower resistance. BD and Cention-N outperformed the MTA-Cention-N, BD-Nanohybrid, and MTA-Nanohybrid combinations. Therefore, BD and Cention-N can be considered preferred materials for restoring pulpotomised maxillary premolars with Class II MOD cavities.