Comparative Evaluation of Surface Roughness, Wettability, and Hardness of Conventional, Heat-Polymerized, Computer-Aided Designed and Milled, and Three-Dimensionally Printed Polymethyl Methacrylate Denture Base Resins: An In Vitro Study.

Introduction The surface characteristics of denture base resins, such as surface roughness, wettability, and surface hardness, are critical determinants of denture success and patient satisfaction. This in vitro study aimed to evaluate and compare the surface characteristics of three fabrication techniques: conventional heat-polymerized polymethyl methacrylate (PMMA), computer-aided design/computer-aided manufacturing (CAD/CAM)-milled PMMA, and three-dimensional (3D)-printed PMMA denture base resins. The objective of this study was to identify the most favorable material in terms of surface quality to assist clinicians in optimizing denture performance and biocompatibility. Materials and methods A total of 120 standardized specimens (25 × 25 × 3 mm) were prepared and divided equally into three groups (n = 40 each). Group I consisted of conventional heat-polymerized PMMA (Triplex Hot, Ivoclar Vivadent AG, Schaan, Liechtenstein). Group II consisted of CAD/CAM-milled PMMA (Ivotion base disc, Ivoclar Vivadent AG, Schaan, Liechtenstein). Group III consisted of 3D-printed PMMA (3D Accuprint Denture, D-Tech, Mumbai, India). All specimens were finished, polished, stored in distilled water, and subjected to thermocycling, followed by immersion in artificial saliva to simulate oral conditions. The surface wettability was measured using the sessile drop method and contact angle analysis. The surface roughness was evaluated using a contact profilometer (Surftest SJ-210, Mitutoyo Corporation, Kanagawa, Japan), and the surface hardness was measured using a Vickers hardness tester (Mitutoyo HM-200, Mitutoyo Corporation, Kanagawa, Japan). Data were statistically analyzed using one-way analysis of variance (ANOVA) and Tukey's post hoc test, with significance set at p < 0.001. Results Significant differences were observed among the three groups (p < 0.001). The highest contact angle was recorded in the 3D-printed group (73.94 ± 2.29°), indicating greater hydrophobicity, while CAD/CAM (73.26 ± 2.37°) and conventional PMMA (68.38 ± 1.93°). The CAD/CAM specimens showed the smoothest surfaces (0.16 ± 0.014 µm), while conventional PMMA was the roughest (0.21 ± 0.019 µm). In terms of hardness, the CAD/CAM specimens exhibited the highest values, significantly outperforming the conventional and 3D-printed groups. Conclusion CAD/CAM-milled PMMA denture bases demonstrated superior surface smoothness and hardness, whereas 3D-printed specimens exhibited the highest hydrophobicity. Digital fabrication methods offer improved surface characteristics compared with conventional techniques, potentially enhancing the clinical performance and longevity of complete dentures.