Short-term effect of mastic gum on salivary concentrations of cariogenic bacteria in orthodontic patients

Objective: To determine antibacterial activity of chewing mastic gum against the salivary levels of Streptococcus mutans, the total number of viable bacteria, and lactobacilli in patients undergoing therapy with fixed orthodontic appliances. Materials and Methods: In this study, the levels of S mutans, lactobacilli, and total cultivated bacteria were measured before and after chewing mastic gum. The antibacterial effects of chewing mastic gum against these microorganisms in saliva were compared with a placebo gum. The counts for orthodontically treated patients were evaluated before chewing gum; just after chewing gum; and after 45, 75, 105, and 135 minutes. Saliva samples taken from the patients were inoculated onto trypticase-yeast-cystine-bacitracin agar for mutans streptococci and onto Rogosa agar for lactobacilli. The agar plates were incubated for 48 hours anaerobically at 37 degrees C. The total number of viable bacteria was then counted. Results: Just after chewing the mastic gum for 15 minutes, a significant decrease of total bacteria and S mutans was observed (P <.001). The reduction in lactobacilli was not significant at later first stage (P >.05). However, at the end of 135 minutes, there were significantly fewer S mutans (P <.001), total viable bacteria (P <.001), and lactobacilli (P <.001) in the oral cavity after chewing mastic gum than after chewing paraffin (P <.001). The results show that chewing mastic gum decreased the total viable bacteria, S mutans, and lactobacilli in saliva in orthodontically treated patients with fixed appliances. Conclusion: Chewing mastic gum might be useful in preventing caries lesions.