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

Abstract

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 μm) 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 (α = 0.05). LU presented higher surface roughness Ra (0.329±0.076 μm) than NE (0.295±0.056 μm) (p = 0.024), but both were similar to CO (0.315±0.058 μm) (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.

Tendency of microbial adhesion to denture base resins: a systematic review

“…As a result of the good surface properties of CAD-CAM milled denture base resins, less microbial adherence is expected. This was confirmed by all authors (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36), who reported that milled denture base resins had lower C. albicans adhesion f and reduce the occurrence of DS in long-term denture use. Di Fiore et al (24) used scanning electron microscope (SEM) to examine the surface topography of each material and found that the conventional ones had multiple grooves and deep scratches with a porous surface, whereas CAD-CAM milled had a smooth surface with fewer scratches.…”

“…C. albicans is most frequently investigated in all included studies except two studies included Candida scotti ( 28 ), and Lactobacillus salivarius , Streptococcus mutans ( 24 ). Different microbial assay methods were included; colony-forming units (CFU) ( 22 , 24 , 29 , 31 , 32 , 34 , 35 ), microscopic evaluation (Mean cell/field) ( 23 , 25 , 29 ), quantified using scanning electron microscopy ( 25 , 26 , 30 , 33 , 36 ), Relative metabolic activity ( 27 ), and Dehydrogenase assays ( 28 ).…”

“…Out of 189, 15 studies (22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36) investigated the effect of microbial adhesion on CAD-CAM milled and 3D printed denture base resins. Two studies compared CAD-CAM milled resins to conventional denture base resins (22,23), and 5 studies compared CAD-CAM milled and 3D printed resins with conventional denture base resins (24,25,31,34,36).…”