ASSESSING THE IMPACT OF VARIED STORAGE TEMPERATURES ON THE MECHANICAL PROPERTIES OF COMPOSITE RESIN: AN IN VITRO STUDY

Abstract

Background: Storage temperature is an important external factor affecting the mechanical properties of composite resins. However, previous studies have reported inconsistent results on the effects of varied storage temperatures. Objective: To systematically evaluate the influence of different storage temperatures (15°C, 25°C, and 35°C) on the flexural strength, compressive strength, surface microhardness, and fracture toughness of a microhybrid composite resin. Methods: A total of 120 specimens were fabricated from a microhybrid composite and divided into 4 test groups (n=30/group) for evaluating the above properties using standardized testing methods. Specimens were stored at 15°C, 25°C or 35°C prior to mechanical testing. One-way ANOVA and post-hoc analyses were conducted to determine differences between storage temperature groups. Results: Refrigerated storage (15°C) decreased flexural strength, compressive strength, and fracture toughness but increased microhardness compared to room temperature storage (25°C). Elevated storage (35°C) reduced fracture toughness without improving strength. Conclusion: Optimal mechanical performance of the microhybrid composite was maintained at 25°C. Storage temperature significantly impacts key properties, with refrigeration impairing strength and elevated temperatures reducing toughness. Manufacturer recommendations should be followed for ideal handling and storage.