Fahad K. Alwithinani^1,, Nouf Al Humayyani¹

Background In dentistry, interest in computer-aided design and computer-aided manufacturing (CAD/CAM) over traditional denture fabrication systems is increasing. However, few studies have compared the physiochemical and biological properties of different fabrication methods. Therefore, the aim of this study was to evaluate and compare the physicochemical properties of different denture materials in terms of surface roughness and Candida albicans adhesion on the basis of polymerization methods and 3D print orientation. Methods Four types of resin disks were prepared: autopolymerization, heat-activated polymerization, milling, and 3D printing. The surface roughness and water contact angle were measured via a profilometer and the sessile drop method. After C. albicans inoculation, microbial adhesion was measured by scanning electron microscope (SEM), a crystal violet assay, and an alcian blue assay. To further investigate the relationship between surface roughness and microbial adhesion, 3D-printed resin was fabricated at different build orientations. The resins were printed at 0, 45, and 90-degrees to modulate different surface roughness and the same experimental set was used. The cell wall thickness of each group was measured via confocal laser scanning microscopy (CLSM). For statistical analysis, one-way ANOVA and Tukey’s post hoc tests were performed. Results The 3D-printed group presented the greatest adhesion with the highest roughness parameters (Ra, Rdq). The milled group presented the lowest adhesion with the lowest surface roughness values. (p < 0.05) Among the 3D-printed samples with different build orientations, the 0-degree presented the lowest surface roughness and the lowest microbial adhesion. (p < 0.05) Microbial adhesion was less related to average roughness and more related to microroughness. The cell wall thickness showed no difference between the groups. (p < 0.05) Conclusion Microbial adhesion is significantly affected by fabrication methods and build orientation. Milled and 0-degree 3D printed resins provide improved options with the potential to minimize Candida albicans adhesion with the lowest surface roughness. Due to their relatively high surface roughness and microbial adhesion, 3D-printed resins with different printing orientations require care and further modifications. This study aims to provide a deeper understanding of surface morphology and microbial adhesion and lead to novel approaches to prevent and manage intraoral infections.

Candida albicans, Denture Bases, Microbial Adhesion, Printing, Three-Dimensional, Surface Properties