In-vitro Comparison of Residual Monomer Content and Water Sorption of Printed, Milled and Conventional Heat-Cured Poly Methylmethacrylate Denture Base Resin.

AIM: This in-vitro study compares the residual monomer content and water sorption of 3D-printed, CAD- CAM and conventional heat cured poly methylmethacrylate (PMMA) denture base materials. MATERIALS AND METHOD: A total of 90 acrylic block specimens were fabricated and divided into three groups (n = 30 per group) based on the type of denture base resin used: 3D-printed PMMA (Group A), CAD-CAM PMMA (Group B), and conventional heat-cured acrylic resin PMMA (Group C). Residual monomer content, measured as methyl methacrylate concentration (MMC), was analyzed using High-Performance Liquid Chromatography (HPLC). Water sorption (μg/mm3) was assessed by immersing the specimens in distilled water at 37°C for varying time intervals (Day 1, Day 7, 1 month, 3 months, and 6 months). The collected data were expressed as mean ± standard deviation, and statistical analysis was conducted using one-way ANOVA, followed by Post hoc tests for pairwise comparisons (α = 0.05). RESULTS: HPLC analysis detected residual methyl methacrylate (MMC) in all denture base resins, with 3D- printed acrylic showing the lowest MMC (0.33% ± 0.06), followed by CAD-CAM PMMA (0.50% ± 0.13), and heat-cured acrylic with the highest MMC (0.87% ± 0.07). For water sorption (μg/mm3), 3D-printed acrylic absorbed the most (11.40 ± 2.27), followed by heat-cured acrylic (9.33 ± 2.11), while CAD-CAM PMMA had the least absorption (6.42 ± 0.93). CONCLUSION: The residual methyl methacrylate concentrations were lowest in 3D-printed acrylic resin, followed by milled resin, with the highest levels found in conventional heat-cured acrylic resin. The water sorption of 3D-printed resins was significantly greater in comparison to conventional heat cured acrylic resin followed by CAD/CAM PMMA.