DEVELOPMENT AND EVALUATION OF NANO-HYDROXYAPATITE AND SILICA-REINFORCED DENTAL COMPOSITES: ENHANCING MECHANICAL STRENGTH AND HYDROLYTIC STABILITY

Abstract

Background: Dental composites are widely used restorative materials; however, their mechanical properties, wear resistance, and hydrolytic stability remain key challenges. Nano-hydroxyapatite (HAp) and silica nanoparticles have shown potential to enhance composite performance by improving strength, durability, and resistance to degradation.
Objective: This study aimed to develop and evaluate novel dental composites incorporating nano-HAp and silica fillers to enhance mechanical strength, wear resistance, and hydrolytic stability.
Methodology: Dental composite samples were fabricated with 0%, 5%, 10%, and 15% nano-HAp-silica filler content. Flexural strength, wear resistance, water sorption, and solubility were assessed following ISO 4049 standards. Mechanical testing was performed at UET Peshawar, and hydrolytic stability was analyzed at Women Dental College, Abbottabad. Statistical analysis was conducted using ANOVA with post-hoc Tukey’s test (p < 0.05).
Results: The incorporation of nano-fillers significantly improved mechanical properties (p < 0.001). Flexural strength increased from 78.5 MPa (control) to 110.8 MPa (15% filler composite), and wear resistance improved with a reduction in material loss from 0.32 mm³ to 0.18 mm³. Water sorption and solubility decreased significantly (p = 0.002), with sorption reduced from 36.8 µg/mm³ to 25.3 µg/mm³ and solubility from 5.2 µg/mm³ to 3.8 µg/mm³, indicating better long-term durability.
Conclusion: Nano-HAp and silica reinforcement significantly enhanced mechanical strength, wear resistance, and hydrolytic stability, making these composites a promising alternative for high-load-bearing dental restorations. Future studies should assess biocompatibility and long-term performance in clinical settings.