Assessment of Salivary pH, Flow Rate, Buffering Capacity and Alpha-amylase Enzyme Activity in Caries-free and Caries-active Children: A Cross-sectional Study

Introduction: It is generally accepted that the caries process is largely controlled by a natural protective mechanism in saliva. The pH, flow, buffering, and remineralising capacity of saliva are recognised as critical factors that affect and regulate the progression and regression of the caries process. Salivary AlphaAmylase (SAA) is an enzyme in saliva that has a high affinity for binding to oral streptococci and plays a role in carbohydrate digestion, potentially leading to enamel demineralisation. Aim: To estimate and associate the pH, flow rate, buffering capacity, and SAA levels in the saliva of children with and without caries. Materials and Methods: A cross-sectional study was conducted in the Department of Paediatric and Preventive Dentistry at Rajarajeswari Dental College and Hospital in Bengaluru, Karnataka, India where 50 children were included. They were divided into two groups: Group A (Caries-active) and Group B (Caries-free), each consisting of 25 children. Unstimulated saliva samples were collected and analysed using a pH meter and Ultraviolet (UV) spectrophotometer, with parental consent and after obtaining ethical clearance. The Mann-Whitney Test was used to compare mean salivary amylase scores between the two groups. An Independent Student’s t-test was used to compare the mean initial pH values, buffering capacity values, and Salivary Flow Rate (SFR) between the two groups. Spearman’s correlation test was conducted, and the level of significance was set at p<0.05. Results: The mean age of the children in the caries-active group was 5.52±0.71 years, while in the caries-free group it was 5.40±0.76 years. Assessment and correlation were conducted between caries scores and all parameters in the study group. Salivary pH, flow rate, and buffering capacity showed a statistically significant negative correlation with caries activity (rho=-0.60, -0.53, -0.38), whereas alpha-amylase showed a statistically significant strong positive correlation with caries activity and caries score. Comparison of the mean values of all parameters based on the number of caries (<6 and >6) showed statistically significant results at p<0.05. Conclusion: Based on the results, it can be concluded that SAA levels were increased in children with Early Childhood Caries (ECC), showing a significant positive correlation with caries activity.