Effect of a novel quaternary ammonium silane cavity disinfectant on cariogenic biofilm formation.

Abstract

Evaluate effect of quaternary ammonium silane (QAS) cavity disinfectant on cariogenic biofilm. Single- (Streptococcus mutans or Lactobacillus acidophilus), dual- (Streptococcus mutans/Lactobacillus Acidophilus), and multi-species (Streptococcus mutans, Actinomyces naeslundii, and Streptococcus sanguis) biofilms were grown on acid-etched dentine discs. Biofilms were incubated (120min/37°C) and allowed to grow for 3days anaerobically. Discs (no treatment) served as control (group 1). Groups II, III, IV, and V were then treated with 2% chlorhexidine, and 2%, 5%, and 10% QAS (20s). Discs were returned to well plates with 300μL of bacterial suspension and placed in anaerobic incubator at 37°C and biofilms redeveloped for 4days. Confocal microscopy, Raman, CFU, and MTT assay were performed. Raman peaks show shifts at 1450cm-1, 1453cm-1, 1457cm-1, 1460cm-1, and 1462cm-1 for control, 2% CHX, 2%, 5%, and 10% QAS groups in multi-species biofilms. There was reduction of 484cm-1 band in 10% QAS group. CLSM revealed densely clustered green colonies in control group and red confluent QAS-treated biofilms with significantly lower log CFU for single/dual species. Metabolic activities of Streptococcus mutans and Lactobacillus acidophilus decreased with increasing QAS exposure time. Quaternary ammonium silanes possess antimicrobial activities and inhibit growth of cariogenic biofilms. Available data demonstrated use of QAS as potential antibacterial cavity disinfectant in adhesive dentistry. Experimental QAS can effectively eliminate caries-forming bacteria, when used inside a prepared cavity, and can definitely overcome problems associated with present available cavity disinfectants.