BackgroundBetel quid chewing, prevalent in Southeast Asia and South Asia, involves components such as betel leaf, areca nut, slaked lime, and sometimes tobacco. This study aims to assess buccal mucosa changes in betel quid chewers, develop a clinical tool for assessing exposure, and investigate its usability in predicting dysplasia.MethodsAfter obtaining ethical approval and informed consent, patients were recruited from the Out-Patient Department of Government Medical College, Omandurar, Government Estate, India. A target sample size of 200 was calculated. The data included the history of betel quid chewing, buccal mucosa cells obtained by oral cytology, and the severity of dysplasia of the slides assessed by pathologists. We utilized principal component analysis (PCA) and confirmatory factor analysis (CFA) to validate a new outcome variable reflecting nuclear morphometric parameters (NMPs). Multiplicative regression models were developed for betel years based on betel exposure and additives. Spearman correlation and Kruskal-Wallis test was used to check the association between betel years and dysplasia.ResultsSignificant differences in NMPs were observed among different betel chewing groups. We derived multiplicative regression models for betel years. In the logarithmic transformation approach, betel year = 0.05×betel-exposure×0.09×slaked-lime use×0.11×tobacco-use. In the original variable approach, betel year = 5.05×betel-exposure^0.00048×slaked-lime-use^0.18133×tobacco-use^1.47513. Spearman correlation and Kruskal–Wallis tests confirmed associations with dysplasia.ConclusionBetel year is a pioneering tool for assessing lifetime betel quid exposure, similar to pack years for smoking. It could aid in risk stratification, targeted interventions and shaping public health policies. Despite limitations, betel year holds promise for revolutionizing oral health risk assessment, and future research can expand its scope globally, considering diverse betel quid compositions.