Relationship between Salivary Flow Rate, Salivary Protein Concentration and Dental Caries Experience among Young Adults in Peshawar, Pakistan

Abstract

Background: Dental caries is a multifactorial, biofilm-mediated disease influenced by microbial, dietary, behavioral and host-related factors. Saliva is an important host-protective factor because it contributes to oral clearance, acid buffering, antimicrobial defense and remineralization of dental hard tissues. Both the quantity and composition of saliva may influence susceptibility to dental caries. Salivary flow rate and protein concentration are relatively simple, non-invasive parameters that may provide useful information about an individual's caries experience.

Objective: To determine the relationship between unstimulated salivary flow rate, total salivary protein concentration and dental caries experience among young adults in Peshawar, Pakistan.

Methods: An analytical cross-sectional study was conducted among 150 young adults aged 18–30 years in Peshawar, Pakistan. Dental caries experience was assessed using the Decayed, Missing and Filled Teeth (DMFT) index. Unstimulated whole saliva was collected over five minutes under standardized conditions. Salivary flow rate was calculated in mL/min, while total salivary protein concentration was determined using a colorimetric biochemical assay and expressed in mg/mL. Descriptive statistics, independent-samples t-test, Pearson correlation and multiple linear regression were performed. Statistical significance was set at p<0.05.

Results: The mean age of participants was 23.8±3.1 years. The mean DMFT score was 3.2±2.8. The mean unstimulated salivary flow rate was 0.31±0.14 mL/min, while the mean total salivary protein concentration was 1.02±0.36 mg/mL. Participants with high caries experience had significantly lower salivary flow rates than those with low/no caries experience (0.27±0.13 vs. 0.36±0.12 mL/min; p<0.001). Conversely, total salivary protein concentration was significantly higher among participants with high caries experience (1.12±0.38 vs. 0.92±0.30 mg/mL; p=0.002). Salivary flow rate demonstrated a significant negative correlation with DMFT (r=-0.36, p<0.001), whereas total protein concentration demonstrated a significant positive correlation with DMFT (r=0.29, p<0.001). In multivariable regression analysis, salivary flow rate and total protein concentration remained significantly associated with DMFT after adjustment for age, sex, sugar consumption and tooth-brushing frequency.

Conclusion: Reduced unstimulated salivary flow rate and increased total salivary protein concentration were associated with greater dental caries experience among young adults in Peshawar. The findings support the potential value of salivary parameters as supplementary indicators of caries susceptibility. However, longitudinal studies and investigation of individual salivary proteins are required before these parameters can be considered reliable predictive biomarkers.