The non-pharmaceutical impact of silicon dioxide nanoparticles in the reduction of fungal growth (Candida albicans) on Vacuum Formed Retainers

Abstract

Aims: This study investigates the efficacy of Silicon Dioxide Nanoparticle (SiO2 NP) coatings as a non-pharmaceutical approach to reduce or prevent oral candidiasis in patients using non-permanent orthodontic retainers, specifically vacuum formed retainers (VFRs).

Methods: We utilised Cetyltrimethylammonium Bromide (CTAB)-tagged, spherical SiO2 NPs with an average diameter of 14 nm, applying them to the surfaces of 96 or 24-well microtiter plates to identify the optimal coating time. Following the nanoparticle coating, we assessed the adherence of Candida albicans (C. albicans) to coupons made from orthodontic materials. This assessment was performed using a stain release assay to compare the levels of adherence in the presence versus the absence of the SiO2 NP coating. This was complemented by a metabolic activity evaluation via resazurin dye and the examination of C. albicans's response under different growth media through light microscopy, aiming to elucidate the interaction dynamics between SiO2 NPs and C. albicans.

Importance and Implications: The research underscores the potential of SiO2 NP coatings to diminish C. albicans colonisation on orthodontic retainers, offering a promising strategy to mitigate oral candidiasis risks associated with removable dental appliances. It lays the groundwork for future studies and clinical trials to explore the effectiveness of SiO2 NP coatings in maintaining oral health, particularly in the context of orthodontic retainer use.

Results: Preliminary findings indicate that SiO2 NP-coated surfaces can reduce the attachment and metabolic activity of C. albicans, associated with its virulence, on polystyrene (PS) microtiter plates. However, an increase in biomass was observed on both treated and untreated orthodontic material coupons made of polyethylene terephthalate glycol (PETG). These results suggest a nuanced interaction between SiO2 NPs and C. albicans, highlighting the potential for SiO2 NP coatings to maintain C. albicans in a less virulent yeast form on polystyrene plastic surfaces, potentially enhancing wearer comfort without promoting the growth of other opportunistic pathogens.