Pyroligneous Extract Varnishes: Antimicrobial, Protective Effects on Demineralization, and Cytocompatibility

Objectives: Varnishes are preparations that differ in the polymeric matrix and therapeutical agents. In dentistry, they are used to prevent caries. The purpose of this in vitro study was to evaluate the antimicrobial activity and protective effect on enamel demineralization, as well as and cytocompatibility of a chitosan varnish containing a pyroligneous extract produced from Eucalyptus spp. (EPECV), considering the Eucalyptus pyroligneous extract properties against pathogenic microorganisms.
Methods: To a chitosan polymeric base (CV) was added a Eucalyptus pyroligneous extract (EPE) characterized and developed by EMBRAPA-CPACT (Patent WO2014100873 A1) at different concentrations (1 to 3%) and formulations: 1% EPECV, 3% EPECV, 3% EPECV + Cu, 3% EPECV + Si and 3% EPECV + 5% NaF. EPE was used as a control and a 5% NaF varnish as a commercial reference. Antimicrobial activity was carried out against Candida albicans, Streptococcus mutans, and Lactobacillus acidophilus through a direct contact test. Enamel surface hardness was chosen as the analytical method to verify the mineral loss per surface area of enamel exposed. The cytotoxicity assay was done toward cells of mesenchymal origin by MTT method. Data were analyzed by one-way ANOVA on ranks (Kruskal-Wallis test).
Results: The results demonstrated the in vitro ability of EPECV to inhibit these microorganisms at low concentrations and possibly prevent and treat oral infections caused by them. The preliminary results showed that EPECV is non-cytotoxic to NIH/3T3 cell line since there were no statistically significant differences (p<0.05) between the test groups and the control group in the different concentrations tested. Data obtained from the percentage enamel mineral change corroborated with commercial varnish findings. In the treatment with the EPECV the enamel surface was also preserved.
Conclusions: Chitosan varnishes containing a pyroligneous extract from Eucalyptus had satisfactory antimicrobial activity against cariogenic bacteria and have a low cytotoxicity.