COMPARATIVE EVALUATION OF ZIRCONIA-, YSZ-, AND PORCELAIN-REINFORCED COLD-CURED PMMA DENTURE COMPOSITES

Abstract

Polymethyl methacrylate (PMMA) has become a staple in dental applications. However, PMMA is inherently fragile and lacks sufficient mechanical strength for specific high stress appl icatio ns. To improve dental restorations and achieve long lasting, appealing results, it is vital to develop denture composites with enhanced mechanical and physical properties. This study explores the mechanical properties of cold cured PMMA denture compo sites reinforced with (1, 3, 5, and 7 wt. %) untreated zirconia (ZrO 2 ) nanoparticles, yttrium stabilized zirconia (YSZ) nanoparticles, and dental porcelain . After the formulated PMMA powder, MMA
monomer, and filler were invested in the mold formed in the d ental flask and compacted with a hydraulic press, flexural strength, impact strength, hardness, and water absorption were evaluated. The results revealed an enhancement in the impact strength for all reinforced PMMA composites, with the highest value obser ved in the composites with 1 wt. % ZrO₂ NPs, YSZ, and porcelain particles marking a 3.50%, 3.04%, and 2.94% increase compared to pure PMMA, respectively. Hardness results for the composites containing 1 wt. % ZrO₂ NPs, 5 wt. %YSZ, and 5 wt. % porcelain par ticles showed the highest increase of 16.48%, 33.4%, and 14.26%, respectively. 7.37% and 64% enhancements in flexural strength were observed for both 1 wt. % ZrO₂ NPs, and YSZ, with a steady decrease for all wt. % of PMMA/porcelain composites when compare d to t he control sample. Generally, water absorption decreased for all reinforced PMMA composites after 48 hours. The best-performing filler overall was YSZ-NP, which exhibited enhanced mechanical properties and water absorption resistance.