IMPLICATION OF PREHEATING ON THE MICROHARDNESS OF GIOMER-BASED BULK-FILL VERSUS CONVENTIONAL BULK-FILL RESIN COMPOSITE: AN IN-VITRO STUDY

Abstract

Introduction: Bulk-fill composite resin, a recently developed restorative material, gained widespread use due to its claimed decreased rate of polymerization shrinkage, increased depth of cure up to 4 mm, decreased restoration time, enhancement of marginal compatibility, and increased bonding ability to dentin. Giomer-based bulk fill is a light-cured restorative material that uses pre-reacted glass-giomer (PRG) filler technology to achieve faster, single-increment (up to 4 mm) placement in posterior teeth. This hybrid material is said to combine the strengths of both composite resins (aesthetics, strength) and glass ionomers (fluoride release) for improved clinical outcomes and efficiency. Materials and Methodology: In this study executed in vitro, 42 specimens were put together using Ivoclar Tetric n-Ceram bulk fill (conventional) and Shofu Beautifil bulk restorative material (giomer-based), for a total of 84 disk-shaped specimens for microhardness testing. The specimens were allocated into 4 groups: Group 1: Ivoclar Tetric-n-Ceram bulk fill with preheating (at 68°C for 15 minutes); Group 2: Ivoclar Tetric-n-Ceram bulk fill without preheating. Group 3: Shofu Beautifil bulk restorative with preheating (at 68°C for 15 minutes); Group 4: Shofu Beautifil bulk restorative without preheating. Microhardness assessment by Vickers test employing a diamond indenter. Statistical comparisons were performed using SPSS software. Results: Preheating of both Conventional and giomer-based bulk-fill composites to a temperature of 68°C appears to significantly improve the microhardness, but the microhardness of conventional bulk-fill was higher compared to giomer-based bulk-fill. Conclusion: Preheating bulk-fill composites upto 68°C improved the microhardness. Substantial variations in the parameter were discovered across different bulk-fill composites, primarily stemming from inherent variations in their chemical constitutions.