Comparative Evaluation of Fluoride Toothpaste with Xylitol Mouthwash Versus Fluoride Toothpaste Alone on Salivary Streptococcus Mutans and Lactobacillus Levels in Orthodontic Patients: A Randomized Controlled in-vivo Study

Abstract

Background: Fixed orthodontic appliances increase plaque retention and promote colonisation by cariogenic organisms, chiefly Streptococcus mutans and Lactobacillus species, raising the risk of white-spot lesions and caries. Fluoride toothpaste is the standard preventive measure, and xylitol-containing mouthwash has been proposed as an antimicrobial adjunct with a mechanism distinct from that of fluoride. Objective: To compare the antimicrobial effect of fluoride toothpaste combined with xylitol mouthwash against fluoride toothpaste used alone on salivary S. mutans and Lactobacillus counts in patients undergoing fixed orthodontic treatment. Methods: Forty-six patients beginning fixed orthodontic treatment were allocated to two groups of 23. Group 1 used fluoride toothpaste (≈927 ppm fluoride) twice daily; Group 2 used the same toothpaste plus a xylitol-containing mouthwash twice daily. Stimulated saliva was collected at appliance bonding (baseline) and after two weeks. Samples were cultured on Mitis Salivarius agar (S. mutans) and Rogosa SL agar (Lactobacillus), and colony counts were expressed as log CFU/mL. Within- and between-group comparisons were performed using paired and independent t-tests. Results: Baseline counts were comparable between groups (p>0.05). Both regimens produced significant reductions at two weeks (p<0.001). Group 1 achieved mean reductions of 1.239 log CFU/mL (S. mutans) and 0.639 log CFU/mL (Lactobacillus). Group 2 achieved markedly greater reductions of 3.291 log CFU/mL (S. mutans) and 2.878 log CFU/mL (Lactobacillus) — approximately 2.7- and 4.5-fold greater than those in Group 1, respectively (p<0.001 for between-group treatment-effect comparison). Conclusion: Adjunctive xylitol mouthwash markedly enhances the antimicrobial effect of fluoride toothpaste against cariogenic salivary flora within two weeks of fixed appliance placement, supporting its use as a short-term preventive adjunct in orthodontic patients at elevated caries risk.