.28 volunteer participants will be assigned in this study. Participants will be randomly divided into two groups(n=14) according to type of toothpaste D where groups D1 patient will use arginine containing toothpaste while groups D2 the patient will used the fluoride toothpaste with a number of 14 patients in each group. The pH will be evaluated according to time in relation to the brushing with toothpaste (T) where (T0) represent salivary pH before brushing with toothpaste , (T1) represent salivary pH 10 minutes after brushing with toothpaste at fixed time of the day.