Objectives: To assess the antimicrobial effect of acid etching or a triclosan-containing compomer on the cultivable microflora of incompletely excavated dentinal carious lesions.
Methods: Thirty detinal lesions were opened with a diamond burr. Subsequent to removal of the softened biomass a sample of dentin was taken from the cavity floor with a round bur. Ten cavities each were treated with 36% phosphoric acid (PH) for 15s, covered with a triclosan-containing compomer (TC) or received no treatment as control (CO). All lesions were restored with a compomer composite. Sampling was performed directly after etching in the PH group and at re-entry after 6 weeks in all groups. Aliquots were plated on blood agar and selective media for Lactobacilli (Rogosa) and mutans Streptococci (MSB). Cultures were incubated anaerobically for 7 days at 37 degrees C prior to quantitative assessment and biotyping of the isolates.
Results: Application of phosphoric acid resulted in initial reduction of the totally cultivable microflora (p=0.006). Evaluation of the total number of cultivable microflora after 6 weeks revealed no differences between the groups (p>0.05). Lactobacilli counts were significantly lower in the TC group compared to the PH and CO groups (p<0.05). No difference was detected between the PH and CO groups after 6 weeks.
Significance: Phosphoric acid initially reduces the number of microorganisms in carious dentin but not in the longer term. The experimental triclosan composite suppresses Lactobacilli species over a period of 6 weeks.