Potencial anticárie in vitro de selantes resinosos e ionoméricos contendo digluconato de clerexidina

Abstract

Sealants are widely used in dental caries control, and its application is indicated for pits and fissures from patients at high risk of developing caries lesions. Chlorhexidine has been incorporated in various dental materials since it can inhibit cariogenic microorganism growth and prevent caries development. This in vitro study aimed to evaluate the effects of chlorhexidine digluconate (CD) incorporation on roughness and anticaries properties of a resin sealant (RS) and a chemically activated glass ionomer sealant (GIS). Chlorhexidine was not incorporated control materials and experimental materials were prepared by adding 0.5% CD(w/w) constituting the groups: RS (Control), GIS (control) SRCD and GISCD. The specimens were evaluated for surface roughness determination, anti-biofilm effect against Streptococcus mutans and inhibition of enamel caries lesion. Three specimens of each material were made with a matrix strip in cylindrical molds. The surface roughness of each specimen was determined using a contact stylus profilometer. Class I Cavities were prepared in bovine enamel blocks (8x8x2 mm3) and restored with control and experimental materials. Three blocks of each group was subjected to S. mutans biofilm formation during 5 days and the effect of the material was tested according to colony-forming units (CFUs) over the samples, in 3 independent biological replicates with 3 technical replicates each. Demineralization represented by integrated area of hardness × lesion depth Delta S (ΔS) was determined on enamel by analysis of cross-sectional microhardness, at 50 and 100 micrometres from the restoration margin. Data were analyzed by two-way ANOVA and Tukey tests, with a pre-set significance level of 5%. No statistically significant difference was found in roughness of the specimens, regardless of material used, incorporated or not with CD (p>0.05). Lower CFU means were found on the blocks restored with resin sealant when compared to those restored with glass ionomer (p=0.011), however, no statistically significant difference was found in for CD incorporation (p = 0.190), regardless of material used. At 50 μm from the restoration, lower demineralization was found for glass ionomer sealants (p<0.001) and for those materials with CD incorporation (p = 0.026), with no interaction between the material used and CD incorporation (p=0.259). At the 100-μmdistance, only glass ionomer sealants were able to reduce demineralization (p<0.001), independent of the CD incorporation. Ionomeric materials have a higher anti-caries effect, however the incorporation of CD appears to be most effective when performed on resin materials.