Microbial adhesion and biofilm formation by Candida albicans on 3D-printed denture base resins

This study evaluated surface properties and adhesion/biofilm formation by Candida albicans on 3D printed denture base resins used in 3D printing. Disc-shaped specimens (15 mm x 3 mm) of two 3D-printed resins (NextDent Denture 3D+, NE, n = 64; and Cosmos Denture, CO, n = 64) and a heat-polymerized resin (Lucitone 550, LU, control, n = 64) were analyzed for surface roughness (Ra mu m) and surface free energy (erg cm(-2)). Microbiologic assays (90-min adhesion and 48-h biofilm formation by C. albicans) were performed five times in triplicate, with the evaluation of the specimens' surface for: (i) colony forming units count (CFU/mL), (ii) cellular metabolism (XTT assay), and (iii) fluorescence and thickness of biofilm layers (confocal laser scanning microscopy). Data were analyzed using parametric and nonparametric tests (alpha = 0.05). LU presented higher surface roughness Ra (0.329 +/- 0.076 mu m) than NE (0.295 +/- 0.056 mu m) (p = 0.024), but both were similar to CO (0.315 +/- 0.058 mu m) (p = 1.000 and p = 0.129, respectively). LU showed lower surface free energy (47.47 +/- 2.01 erg cm(-2)) than CO (49.61 +/- 1.88 erg cm(-2)) and NE (49.23 +/- 2.16 erg cm(-2)) (p<0.001 for both). The CO and NE resins showed greater cellular metabolism (p<0.001) and CO only, showed greater colonization (p = 0.015) by C. albicans than LU in the 90-min and 48-hour periods. It can be concluded that both 3D-printed denture base resins are more prone to colonization by C. albicans, and that their surface free energy may be more likely associated with that colonization than their surface roughness.