Salivary physicochemical parameters as potential biomarkers for common oral ulceration

Oral ulceration is the most common oral mucosal disease, affecting 20–25% of the population and resulting in a 50% recurrence rate. Human saliva, a critical biological fluid, maintains oral health, reflects local and systemic changes, and is a reliable diagnostic tool for detecting ulcer progression and healing. To analyze and compare salivary physicochemical properties between patients with common oral ulceration and healthy individuals in Sri Lanka, and to determine independent and interactive effects of age, sex and disease status on these parameters. A comparative, prospective cross-sectional study was conducted among 63 patients with common oral ulceration and 63 healthy controls recruited from the Diagnostic clinic, University of Peradeniya, Kandy, Sri Lanka. Unstimulated whole saliva was collected from participants aged≥ 18 years between 8.30 and 11.30 a.m. Samples were collected over 5 min and analysed immediately. Salivary pH, electrical conductivity, flow rate, buffer capacity, and colour were measured via standardised protocols and calibrated instruments. The effects of age and sex on salivary parameters were also evaluated via appropriate statistical analyses. Patients with common oral ulceration exhibited significantly lower salivary pH (6.55 ± 0.42 vs. 7.18 ± 0.26, p < 0.001), unstimulated salivary flow rate (0.449 ± 0.158 vs. 0.579 ± 0.213 mL/min, p = 0.0001), and buffering capacity (6.60 ± 0.43 vs. 7.09 ± 0.29 M/pH, p < 0.001), but significantly higher electrical conductivity (3.41 ± 1.39 vs. 2.65 ± 0.91 mS/cm, p < 0.001) compared with healthy controls. Salivary colour variations were observed in 31.7% of patients with oral ulcers but were not observed in healthy controls. After adjustment for age and sex, disease status remained an independent predictor of salivary physicochemical parameters. Age was independently associated with unstimulated salivary flow rate, whereas sex showed no overall independent association. However, sex may modify age related associations with salivary pH, unstimulated salivary flow rate and buffer capacity. Common oral ulceration was associated with lower salivary pH, buffering capacity, and unstimulated salivary flowrate and higher electrical conductivity. Specifically, salivary pH, buffering capacity, and unstimulated salivary flow rate may have potential as non-invasive indicators of common oral ulceration; however, age and sex related effects should be considered when interpreting these parameters. These findings support further investigation and clinical validation of salivary physicochemical parameters as non-inversive biomarkers for oral health assessment.