Antimicrobial effect of chitosan incorporated resin sealant on Lactobacillus casei

Background: Resin sealant has been used to prevent pit and fissure caries for decades. Antimicrobial effect of chitosan can be foreseen as interesting means to enhance caries prevention. Nano-whiskers chitosan was synthesized and incorporated into resin sealant expecting antimicrobial activity. Objectives: The present study aimed to investigate in vitro antimicrobial activities of nano-whiskers chitosan incorporated resin sealant on Lactobacillus casei (IFO 3533). Methods: An experimental light-activated resin sealant was prepared from Bis-GMA and TEGDMA monomers. Novel chitosan nano-whiskers were developed from shrimp shells (Litopeneous vannamei). The shells were decalcified and deproteinized to obtain chitin flakes. The flakes were hydrolyzed to form nano-whiskers. The nano-whiskers were deacetylated for chitosan. After lyophilization, dry nano-whiskers were incorporated into the experimental resin sealant at 1, 1.5, 2, 2.5% by weight. Three disc specimens (5mm in diameter and 2mm in thickness) were prepared for the experimental sealant, the chitosan incorporated sealants, Teethmate™F-1 (Kuraray, Japan), Seal&Protect™ (Dentsply, USA) and Delton® (Dentsply, USA). The antimicrobial activities were determined by an agar diffusion method and a colony forming unit count technique. Results: Each disc of Seal&Protect™, Teethmate™F-1, 2.5%, 2% and 1.5% nano-whiskers chitosan incorporated sealants clearly demonstrated an inhibitory halo. Bacterial reduction rate of the 1.5% chitosan incorporated sealant was statistically higher than the control sealant, Delton® and 1% chitosan incorporated sealant. (ANOVA, Scheffe; p<0.05) Conclusion: Incorporation of at least 1.5% chitosan nano-whiskers into a light-activated experimental resin sealant showed antimicrobial effect both qualitatively and quantitatively. The study was supported by the Faculty of Dentistry, Chulalongkorn University Fund.