Oral Health Consequences of Smokeless Tobacco Use: A Narrative Review.

Smokeless tobacco (SLT), including snus, chewing tobacco, naswar, and nicotine pouches, is widely used and often perceived as a safer alternative to smoking. Among current users of SLT, mucosal alterations-most commonly smokeless-tobacco keratosis and white plaque-like lesions-are frequently observed at product placement sites, such as between the lip and gum, with patterns closely linked to the frequency and duration of use. Several reports describe partial or complete regression of these lesions after discontinuation. Periodontal findings are mixed: increased gingival recession - particularly at anterior sites corresponding to product placement - appears consistently, whereas links with deeper periodontal destruction are inconsistent and often confounded by oral hygiene and concomitant cigarette smoking. Additional oral effects observed with SLT use include extrinsic staining, tooth wear or abrasion, and increased caries prevalence associated with products containing sweeteners or coarse particulates. Regarding malignancy, signals from observational literature indicate an association between SLT exposure and oral squamous cell carcinoma (OSCC), although the magnitude of risk appears to vary by product chemistry (e.g., nitrosamine content, pH), processing methods, and regional usage patterns. Evidence remains heterogeneous, limiting direct comparisons across products and populations. Small biomarker studies also report elevated salivary pro-inflammatory cytokines (IL-6, IL-8, and TNF-α) among users with mucosal changes, but clinical utility is uncertain. Overall, current evidence links SLT with frequent, often reversible local mucosal alterations, consistent placement-site gingival recession, and a possible product-dependent elevation in OSCC risk. These observations underscore the importance of establishing uniform definitions for outcomes and consistent measures of exposure in studies of SLT to facilitate valid comparisons across different products and populations. In addition, further research is warranted to explore the motivations for SLT use and to delineate dose-response relationships and potential malignant transformation, with particular attention to emerging nicotine pouch products.