Antimicrobial effect of chitosan nano-whiskers incorporated resin sealant on S.mutans
Mahapoka E., Arirachakaran P., Rujiravanit R., Poolthong S.
Objective: The aim of this study was to investigate in vitro antimicrobial activities of a chitosan nano-whiskers incorporated resin sealant on Streptococcus mutans (UA159). Methods: Novel chitosan nano-whiskers developed from the shrimp shells (Litopeneous vannamei) were primarily decalcified and deproteinized to obtain chitin flakes. The flakes were hydrolyzed under acidic condition to form novel nano-whiskers. The nano-whiskers were deacetylated using alkali reagent for chitosan. Fourier Transform Infrared Spectrometry (FTIR) and Transmission Electron Microscope (TEM) were used to determine chemical and physical characteristics, respectively. After lyophilization, dry whiskers were incorporated into a light-activated experimental resin sealant at 0 (control), 1, 1.5, 2, 2.5% by weight. Three disc specimens (5mm in diameter and 2mm in thickness) were prepared for each experimental sealant, Seal&Protect™ (DENTSPLY, USA), Delton®(DENTSPLY, USA), Teethmate™F-1 (KURARAY, Japan). The antimicrobial activities were determined by the agar diffusion method and the colony forming unit count technique. Results: An infrared spectrum exhibited essential functional group peaks of chitosan chemical structure. The degree of deacetylation of chitosan nano-whiskers calculated from the spectrum was found to be 83.58%. TEM images depicted distributed fibrous nano-structures which were ranged from 328-965 nm in length and 20-87 nm in width. Each disc of Seal&Protect™, Teethmate™F-1, 2.5% and 2% chitosan incorporated sealants clearly demonstrated an inhibitory halo. Bacterial reduction rate of the 2% chitosan incorporated sealant was statistically higher than Delton®, 1.5%, 1% and 0% chitosan incorporated sealant. (ANOVA, Scheffe, p<0.05) Conclusion: The novel chitosan nano-whiskers were developed. Incorporation of at least 2% nano-whiskers in a light-activated resin sealant showed antimicrobial effect.