Investigation of candidal colonization and adhesion on various dental restorative materials: An in vitro study.

STATEMENT OF PROBLEM: Colonization of Candida on dental restorative materials presents a significant risk for dental structures and oral mucosa, particularly in immunocompromised individuals or those with poor oral hygiene.

PURPOSE: This study aimed to investigate the adhesion and biofilm formation of Candida albicans (C. albicans) on 6 commonly used dental restorative materials: composite resin, amalgam, lithium disilicate, zirconia, heat-polymerized acrylic resin, and cobalt chromium (Co-Cr) alloy.

MATERIAL AND

METHODS

Surface characteristics, including roughness and hydrophobicity, were evaluated using atomic force microscopy and contact angle measurements. The Candida biofilm formation was evaluated using crystal violet assays as optical density (OD). The expression of adhesion and biofilm-forming genes (ALS1, ALS3, and HWP1) was quantified via real-time quantitative polymerase chain reaction (qPCR). The morphology of Candida biofilm on the surface of different materials was also investigated using scanning electron microscopy (SEM).

RESULTS

The order of materials in terms of surface roughness was composite resin>amalgam >Co-Cr alloy>zirconia>lithium disilicate>acrylic resin, and in terms of contact angle was amalgam>composite resin=Co-Cr alloy>acrylic resin>zirconia>lithium disilicate. The composite resin and amalgam exhibited the highest surface roughness and hydrophobicity, correlating with increased C. albicans adhesion (OD of 0.43) and biofilm formation (OD of 0.88). In contrast, smoother and more hydrophilic materials like lithium disilicate demonstrated lower Candida colonization (OD of 0.28). The expression of tested adhesion-related genes was significantly elevated on surfaces with high roughness and hydrophobicity. Furthermore, C. albicans appeared as isolated cells on composite resin and lithium disilicate, while it was uniformly distributed on acrylic resin, zirconia, and Co-Cr alloy. On amalgam, it formed short biofilms in surface grooves.

CONCLUSIONS

The results emphasize the importance of selecting restorative materials with smoother, hydrophilic surfaces to minimize candidal colonization.