Comparative Evaluation of Surface Roughness in CAD/CAM-milled, 3D-printed, and Conventional Polymethyl Methacrylate Denture Base Resin Materials: An In-vivo Study

Introduction: The surface roughness of denture-base resins significantly affects biofilm accumulation, aesthetics, and patient comfort. With advances in digital dentistry, CAD/CAM-milled and 3D-printed resins offer new fabrication options; however, their surface properties require further validation under clinical conditions. Aim: To compare and evaluate the surface roughness of CAD/ CAM-milled, 3D-printed, and conventional heat-polymerised acrylic Denture Base Materials (DBMs) under in-vivo conditions. Materials and Methods: A comparative clinical in-vivo study was conducted in the Department of Prosthodontics, Hitkarini Dental College and Hospital, Jabalpur, Madhya Pradesh, India, from August 2023 to February 2025 on 270 disc specimens fabricated and equally distributed among three groups (n=90): Group A-CAD/CAM-milled; Group B-3D-printed; Group C-conventional heat-polymerised resin. Denture-base samples (6×2 mm) were embedded in the flanges of the dentures. After three and six-months of clinical use, the samples were retrieved and surface roughness was assessed using a contact profilometer; mean roughness values (Ra) were recorded and subjected to statistical analysis. Results: The CAD/CAM-milled resin consistently showed the lowest surface roughness at all time points, whereas 3Dprinted resin exhibited the highest. Conventional PMMA resin showed an intermediate value. The interaction effect of material type and time was statistically significant (F=13271.91, p<0.05), confirming that CAD/CAM-milled resin maintained the smoothest surface, whereas 3D-printed resin demonstrated the greatest roughness progression over time. Differences among all three groups were statistically significant (p<0.001). Conclusion: The CAD/CAM-milled denture-base resins demonstrated superior surface smoothness compared with 3D-printed and conventional materials. The smoother surface of milled resins may promote better hygiene, reduce plaque accumulation, and enhance patient comfort, supporting their use in long-term prosthodontic care.