3D-printed denture base resins: Glazing as an alternative to improve surface, mechanical, and microbiological properties

Purpose: To evaluate the impact of glazing denture base resins (heat-polymerized and 3D-printed) on surface, mechanical, and microbiological properties. Materials and Methods: Discs (10 × 3 mm) and bars (64 × 10 × 3.3 ± 0.2 mm) were manufactured using heat-polymerized denture base resin (CT) and 3D-printed denture base resin (Yller [YL], Prizma [PZ] and PrintaX [PX]). These were divided into two groups: unglazed and glazed. Surface roughness (Ra), wettability (contact angle), brightness (GU), and topography (via scanning electron microscopy) were assessed, along with microbiological analysis of dual-species biofilms (Streptococcus mitis and Candida albicans) and Knoop microhardness on discs (n = 10). Flexural strength testing was conducted separately on bars (n = 20). Half of the specimens subjected to surface and mechanical characterizations were thermocycled (10,000 cycles). Mann–Whitney test (p < 0.05) and simple and multiple linear regression analysis (p < 0.20) were employed to evaluate the impact of glazing on denture base resins. Results: The application of glaze reduced roughness by 0.33 µm and water contact angle by 8.47º, while increasing brightness by 21.30 units (p < 0.001) for 3D-printed resins compared to CT. After thermal cycling, roughness and wettability increased, while brightness decreased (p < 0.05). The glaze also increased hardness, with no adverse effects from thermal cycling (p < 0.001), and enhanced flexural strength for PZ compared to CT (p < 0.001). Additionally, C. albicans colonization decreased by 7.79 log CFU/mL in mixed biofilms for 3D-printed resins compared to CT (p < 0.05). Conclusions: The application of glaze resulted in smoother, brighter, and harder surfaces for the 3D-printed resins, while also reducing biofilm colonization.