The objective of this study was to evaluate the effect of short-term consumption
of probiotic powdered milk containing Lactobacillus paracasei SD1 on the level of salivary yeast in orthodontic treated cleft lip and palate patients. A total of 30 cleft lip and cleft palate patients who had been undergoing orthodontic treatment with fixed orthodontic appliances at the Dental Hospital, Faculty of Dentistry, Prince of Songkla University, were divided into two groups; the study and control groups. The study group, consisting of 15 subjects, received 10 g/50 ml/day of probiotic powdered milk containing Lactobacillus paracasei SD1, while the 15 subjects in the control group received 10 g/50 ml/day of
normal powdered milk. Both groups were advised to drink the provided milk daily after breakfast for 30 days. The salivary yeast level, plaque index (PI) and salivary pH were investigated before milk consumption (I), immediately (T0) and at one week intervals after completed the 30-day period of milk consumption for 4 weeks (T1, T2, T3, T4). There was a statistically significant decrease of the salivary yeast level (p < .05) found at T0-T4 within the study group comparing to the baseline. However, there was no statistically significant change within the control group. When compared between the two groups, there was a statistically significant difference in the percent change from baseline level
of salivary yeast at T0-T4. No statistically significant difference was found in the salivary pH and plaque index between the two groups throughout the study. In conclusion, the short-term consumption of probiotic powdered milk containing Lactobacillus paracasei SD1 could decrease the salivary yeast counts in the orthodontic treated cleft patients.