Layer by layer nanocoating of chlorhexidine-loaded micelles on polymethyl methacrylate denture base

Denture stomatitis is a prevalent oral infection commonly affecting denture wearers with inadequate oral hygiene cares. This susceptibility stems from the porous and rough nature of denture bases, which readily harbor bacteria and promote plaque accumulation. This study aimed to modify the surface of denture bases with a chlorhexidine (CHX) coating to promote antimicrobial activity against Candida albicans.

Denture bases were coated with chlorhexidine-loaded poly(ethylene glycol)-block-poly(ε-caprolactone) micelles (CHX-micelles) using the solvent evaporation method. The surface was coated using a layer-by-layer (LbL) dip coating process involving CHX-micelles and poly(acrylic acid) (PAA). The total number of LbL coating cycles was adjusted, and the coating thickness, drug content, CHX-release, antimicrobial activity, and toxicity of the coated denture base were evaluated. One-way ANOVA and Two-way ANOVA were performed. Statistical significance is defined as p < 0.05.

The optimized coated denture base, with 90 layers, achieved a maximum coating thickness of 13.33 ± 2.41 μm and a CHX content of 23.64 ± 4.71 µg/cm². This coating exhibited sustained CHX release over 14 days. Even with a non-polished side, the coated surface displayed a reduced contact angle, which would decrease fungal adhesion. The adherence of C. albicans to the surface was also significantly reduced by the antifungal activity of CHX-micelles coated denture base, and this activity sustained for 14 days. Whereas free CHX decreased cell viability to less than 80% with 50, 75, and 100% of extracted solution, CHX-micelles contributed more than 85% of cell viability, comparable to non-coated denture base.

The development of antimicrobial denture bases using this coating method has shown promising results. The optimized coating effectively prolonged CHX release, inhibited fungal growth, and maintained biocompatibility.