Smoking-induced changes in saliva composition and tongue coating

Saliva parameters and tongue coating have global significance because they offer simple, non-invasive indicators of oral and systemic health, helping clinicians and researchers detect disease risk, monitor wellness, and improve early diagnostic strategies across diverse populations.

This study aimed to investigate the effects of smoking on salivary flow rate, pH, buffering capacity, and tongue coating characteristics among adult smokers and nonsmokers.

A cross-sectional study was designed to compare salivary parameters and tongue coating between smokers and nonsmokers. A purposive sampling method was used. The data collected included patients' resting and stimulated saliva pH, saliva buffering capacity, and tongue coating for both smokers and nonsmokers. The inclusion criteria required the absence of systemic illness and medication that affected saliva flow.

A total of 78 participants were assessed for unstimulated and stimulated saliva flow, salivary pH, buffering capacity, and tongue coating (thickness, area, and colour). Smokers exhibited significantly reduced buffering capacity (p = 0.002) and increased tongue coating thickness and distribution area (p = 0.008 and p = 0.000, respectively), though saliva flow and pH differences were not statistically significant.

These findings indicate that smoking is associated with reduced salivary buffering capacity and increased accumulation of tongue coating. Smoking may therefore represent a modifiable behavioural factor influencing salivary defence mechanisms and oral ecological balance. Integrating tongue coating and saliva analysis into caries risk assessment protocols could support earlier identification of individuals at increased risk.