Comparative study on the effects of four commercial chewing gums on PH, bacterial count and streptococcus mutans of saliva

Comparative study on the effects of four commercial chewing gums on PH, bacterial count and streptococcus mutans of saliva Dr. M. Karami Nogourani* -Dr. H. Ghasemian Safai**- Dr. A. Ahmadi***- T. Narimani****- F. Poorsina**** * - Assistant Professor of Pedodontics Dept. - Faculty of Dentistry – Islamic Azad Khorasgan University. ** - Assistant Professor of Microbiology Dept. – Faculty of Medicine – Isfahan University of Medical Sciences. *** - Dentist. **** - Faculty member of Microbiology Dept. Faculty of Medicine – Isfahan University of Medical Sciences. Background and Aim: Numerous studies have shown the role played by sugar – free chewing gums in the reduction of dental caries. The goal of this study was to compare the effects of three commercial sugar free chewing gums and one containing sucrose on streptococcus mutans and pH of saliva. Materials and Methods: This randomized clinical trial research was conducted on 120 female students of a day – night high school for seven weeks. The subjects were randomly divided into four groups. One group used a commercial sucrose – containing gum named Aidin (group A) and three groups used sugar – free gums named Relax (group B), Dirol (group C) and Happy dent (group D). The subjects used three gum sticks daily after main meals for about five minutes. Saliva sampling was performed unstimulated at three times: at baseline, at the third and seventh weeks, after sleep and before tooth brushing. Samples were immediately transferred to microbiology department of medicine faculty, Isfahan University. Data were subjected to repeated measure, Hottelling's trace and t – paired tests and compared by Variance (ANOVA) and DUNCAN analyses. Results: During the first three weeks, all groups even the sucrose – containing gum group showed a significant decrease in the salivary streptococcus motans: A (P=0.038), B (P<0.001), C (P=0.035) and D (P=0.033), but between the third and seventh weeks, the decreases were only significant in groups C and D (P=0.024) and (P=0.001). However, intergroups comparison showed that, in spite of the third week, the decrease of salivary streptococcus motans, in the seventh week was statistically significant in groups B, C and D, as compared with group A, (P<0.05). Salivary PH, in group A, despite other groups, showed a significant decrease in the seventh week of sampling (P=0.005) and the observed difference between groups A and D was statistically significant (P<0.05). One of the other interesting findings was the significant increase of the salivary bacterial colonies, other than streptococcus mutans, in group B during the seven weeks of study (P<0.001). Conclusion: Three – week chewing of any type of gum after main meals could decrease the level of salivary streptococcus mutans, however during a seven – week period, the decreasing effects of sugar – free gums were significantly higher. Key words: Chewing gum – Saliva – Streptococcus mutans.