The current research was conducted to evaluate the relationship between the type, value and frequency of carbohydrates consumed and saliva pH and dental decay in elementary school students of Ahvaz city in 2015. The research method is randomized clinical trial type of descriptive-analytical study. Accordingly, 336 healthy elementary students aged 7 to 13 and had no any mental and physical illness, were selected by informing at Jondishapur University of Medical Sciences in Ahwaz. Questionnaire was used as tool of data collection. A demographic questionnaire to record the anthropometric measurements (weight, height, BMI) and a 3-day food recording questionnaire (two normal days and one holiday) were filled out by parents and students. The guideline on filling out of the food recording questionnaire was explained in detail for subjects. The recorded information included time of consuming, type of food or drink consumed, cooking method and value of food consumed. In addition, one sample of non-stimulating saliva (about 2 cc) was taken and measured immediately by Metrohm digital pH meter. The status of teeth was examined at school and the appropriate environment. Since results of previous studies show that use of oral saliva pH has relationship with dental decay, non-stimulating saliva was used as an appropriate sample to achieve high precision results. Saliva samples were measured by digital pH meters. The collected data were analyzed by using SPSS21 software. Pearson correlation coefficient was used to examine the relationship between the research variables. In addition, p <0.05 was considered as a significant value. The results generally revealed a reverse relationship between saliva pH and dental decay. A direct relationship was also found between lactose, sucrose, and total carbohydrate intake and DMFT. Among Intricic, Milk, and Non-milk types of carbohydrates, Intrisic carbohydrate showed direct relationship with dental decay. A reverse relationship was also found between lactose, sucrose, and total carbohydrate intake and saliva pH.
