Caries prevention effects of nano silver fluoride sustained release orthodontic elastomerics in dental microcosm biofilms

Abstract

Objectives: To evaluate the clinical applicability of nano silver fluoride sustained release orthodontic elastomerics (NSF-RE) by investigating its effects on inhibiting biofilm formation and enamel demineralization using dental microcosm biofilms.

Methods: Two types of 23 % NSF coating solutions were prepared depending on the presence or absence of the plasticizer (polyethylene glycol [PEG] 6000: NSF-EP and NSF-E); the elastomerics were dip-coated individually with these. Biofilms were allowed to form on bovine enamel specimens with the elastomerics. Biofilm maturity (red/green ratio) was measured. After 7 days, biofilm thickness, live/dead cell ratio, and cell viability were evaluated. Microbiome taxonomic profiling was conducted on days 3 and 7. Mineral loss beneath the biofilm was quantified from fluorescence loss (ΔF) and ΔFmax values obtained. Demineralization at varying distances from the specimen center was evaluated based on the difference in ΔF between the control and experimental groups.

Results: The NSF-EP (elastomerics treated with NSF coating containing PEG) had a 6.7 % significantly lower R/G ratio from day 3 and a 36.1 % thinner biofilm compared to the negative control with uncoated elastomerics. In the NSF-EP group, cell viability assessments indicated reductions in total and aciduric bacterial counts by 9.4 % and 13.0 %, respectively. NSF-EP also had the lowest relative abundance of five caries-related bacteria. Additionally, NSF-EP significantly increased ΔF and ΔFmax by 34.8 % and 38.7 %, respectively, indicating reduced mineral loss. Demineralization did not differ according to distance from the elastomerics.

Conclusion: NSF-RE significantly reduces biofilm formation and demineralization, offering a promising caries prevention strategy in orthodontic patients.

Clinical significance: By inhibiting both biofilm formation and demineralization, NSF-RE provides a dual-function approach that may effectively prevent dental caries in orthodontic patients.