Journal of Dental Medicine

Background and Aims: Soy milk in competition with other drinks introduced as healthy and nutrient drink. Nowadays, most important tendency to consume soy milk is new extended developments to produce soy milk with more acceptable taste and is believed that soy milk is a good substitute for bovine milk in lactose-intolerant people. Cariogenic potential of bovine and soy milk is a subject for lots of researches in the last decade. The aim of this study was to evaluate the effect of soy and bovine milks on the pH changes of dental plaque.

Materials and Methods: In this study, 10 healthy dental students in age range of 25-35 were selected after written consent upon study entrance criteria's such as, amount of saliva streptococcus mutans, amount of lactobacillus, salivary secretion rate, buffering capacity of saliva, absence of active dental caries, absence of systemic disease and etc. Dental plaque pH in the interproximal areas of 2nd premolar and 1st molar in all 4 quadrants was taken by Metrohm micro electrode and digital pH meter before (0) and at 2, 5, 7, 10, 15, 20, 30, 40, 50 and 60 min after taking with 3 tested materials (soy milk, plain milk 1.5% and 10% sucrose solution as a positive control). Then pH curves were drawn according to the time of each test product. In this study, using pH=6 was considered as critical pH. Maximum pH drop and ∆pH after taking 3 tested materials were analysed Repeated measure ANOVA (P<0.05).

Results: According to the test materials, the lowest pH was after rinsing with 10% sucrose solution following soy milk and in the last was 1.5% bovine milk. All the test materials showed significant differences among each others
(P<0.05).

Conclusion: Bovine milk in none of frequent timing dropped its pH below basic pH but also significantly increased the plaque pH above the critical pH. The maximum pH drop for soy milk was in 2minutes after consumption but it never reached below the critical pH.