Evaluation of the effects of probiotic pills on the oral plaque indices: A randomized clinical trial

Clinical trials investigating the efficacy of oral health prevention materials have conventionally used indices to evaluate the amount of plaque on tooth surfaces. Various methods, including the use of probiotics, have been suggested to prevent oral disease. The present study was conducted to investigate the probiotic products available in Iranian pharmacies that are used for the prevention of dental disease.

In this double-blind randomized clinical trial, 40 students of medicine and pharmacy were randomly allocated into two equal groups of intervention and control using random allocation software. The intervention group used a probiotic pill containing Streptococcus salivarius M18 and K12 bacteria every night before going to bed. The control group used a mouth freshener tablet with the same flavor as the probiotic tablet every night before going to bed. The mean number of Streptococcus mutans bacteria in both the groups was calculated before and after using probiotic pills. The data were staticali analyzed by descriptive statistics (central tendency and dispersion) and inferential statistics (paired t-test and independent t-test) and Kolmogorov-Smironove tests (P<0.05).

The plaque index values at the beginning of the study showed no statistical differences between the intervention and control groups (P = 0.85). The plaque index values in the intervention group before and after the intervention were 0.41 and 0.75, respectively, which showed a statistically significant difference (P < 0.05). The plaque index values in the control group before and after the intervention were 0.42 and 0.42, respectively, which indicated no statistically significant difference (P > 0.05).

The mean plaque index in the group using probiotic tablets was significantly increased compared to those of the control group. However, further studies are suggested to evaluate these products.