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

Abstract

To evaluate the impact of glazing denture base resins (heat-polymerized and 3D-printed) on surface, mechanical, and microbiological properties. Discs (10×3mm) and bars (64×10×3.3±0.2mm) 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. 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). The application of glaze resulted in smoother, brighter, and harder surfaces for the 3D-printed resins, while also reducing biofilm colonization.