Effects of sodium fluoride solution, chlorhexidine gel and fluoride varnish on the microbiology of dental plaque – A randomised controlled trial

Abstract

Background: Reducing microbial load in the oral cavity will provide an additional rationale for the prevention of dental diseases. Antibacterial properties of topical fluorides and chlorhexidine (CHX) are well documented with certain limitations. However, effects of topical applications of 2% sodium fl uoride solution (NaF soln), 1% CHX gel, and 2.26% NaF varnish on plaque microfl ora and following its termination are less explored. Hence, there is a need to study the comparative effects on these agents in vivo. Aim: The aim was to assess quantitative and qualitative changes in the plaque microflora following topical application of 2% NaF soln, 1% CHX gel, and 2.26% NaF varnish. Materials and Methods: This was a double-blind, randomized, parallel-group clinical trial. A total of willing sixty schoolchildren of Nellore city with apparently good health aged 9–13 years were randomly allocated to three interventional groups as follows: Group A (NaF soln, 20), Group B (CHX gel, 20), and Group C (NaF varnish, 20). NaF soln and CHX gel were applied four times on a weekly interval and NaF varnish was applied only once. Once patients enrolled to participate in the clinical trial, an identification number was sequentially assigned, allowing maintenance of a double-blind, randomized study design. Plaque samples were collected at baseline (P0) and at seven different time intervals (P1: 1st week, P2: 2nd week, P3: 3rd week, P4: 4th week, P5: 8th week, P6: 12th week, and P7: 16th week) and cultured on nutrient agar medium. The number of microbial colony-forming units (CFUs) was calculated using a digital colony counter. Statistical significance within and between groups was calculated using Chi-square test, paired t-test, ANOVA, Dunnett's multiple comparison test, and Tukey's multiple comparison test. Results: There was reduction in the CFU in all the three groups at P2, P3, and P4 when compared to P0 (P 0.05). Single application of NaF varnish was equally potent as four times application of NaF soln and CHX gel, but there was no statistical significance in-between groups in terms of CFU reduction (P > 0.05). P7 sample estimation showed Lactobacilli species with 100% resistance followed by other organisms. Conclusion: All the three agents used demonstrated significant reduction of microbial load in plaque but allowed recolonization following termination of intervention.