Background The long-term performance of heat-cure denture base resins depends largely on their mechanical properties. Heat-cured acrylic resins are widely used in removable prosthodontics because of their practical handling characteristics and acceptable overall clinical utility. The reinforcement of denture base resins with metal oxide fillers has been proposed to improve their resistance to fracture. The present study aimed to evaluate and compare the effects of aluminum oxide and zinc oxide fillers on the impact and flexural strength of heat-cured denture base resins. Methodology This in vitro experimental study was conducted at the Department of Prosthodontics, Jawahar Medical Foundation’s Annasaheb Chudaman Patil Memorial Dental College and Hospital, Dhule, Maharashtra, India. The control group (Group 1) (n = 17) consisted of conventional heat-cured denture base resin specimens, Group 2 (n = 17) consisted of aluminum oxide-reinforced specimens, and Group 3 (n = 17) consisted of zinc oxide-reinforced specimens. The flexural strength was evaluated in megapascals (MPa) using a universal testing machine using the three-point bending test method, whereas the impact strength was assessed in kilojoules per square meter (kJ/m²) using the impact test method. Statistical analysis was performed using the Kruskal-Wallis test followed by the Mann-Whitney U test with Bonferroni correction. Results The aluminum oxide-reinforced group demonstrated the highest mean flexural strength value (402.94 ± 57.20 MPa), followed by the zinc oxide-reinforced group (164.71 ± 55.24 MPa), whereas the control group showed the lowest value (93.33 ± 22.04 MPa). Similarly, the highest mean impact strength was observed in the aluminum oxide-reinforced group (3.13 ± 1.00 kJ/m²), followed by the zinc oxide-reinforced group (2.22 ± 0.59 kJ/m²) and the control group (1.44 ± 0.31 kJ/m²). Statistically significant differences were observed among all study groups for both flexural and impact strengths (p < 0.001). Conclusions The incorporation of aluminum oxide and zinc oxide fillers significantly improved the flexural strength and impact strength of the heat-cured denture base resin compared with the conventional acrylic resin. The aluminum oxide reinforcement demonstrated superior enhancement of the mechanical properties compared to the zinc oxide reinforcement. The reinforcement of denture base resins with metal oxide fillers may improve the durability and fracture resistance of removable prostheses.
Bhairi et al. (2026) studied this question.