Mapping the Conceptualization and Measurement of (In)Equity in Oral Health Among Middle-Aged and Older Adults: A Scoping Review

Background As populations age oral health needs increase, widening health differences among older adults, making the monitoring of health (in)equity increasingly important. Oral health, shaped by cumulative structural disadvantage, serves as a valuable indicator of (in)equity but remains underrepresented in equity-focused research. In aging populations, it is often unclear whether health decline reflects biological aging or avoidable social disadvantage, making the concept of (in)equity particularly complex. To ensure meaningful analysis, it is essential to understand how equity is conceptualized and how that conceptualization informs its measurement. This scoping review aimed to examine how (in)equity in oral health is defined, interpreted, and measured in studies of middle-aged and older adults. Materials and Method This scoping review was conducted in accordance with the PRISMA-ScR guidelines. Six electronic databases: MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Systematic Reviews, Scopus and ProQuest were searched from inception to March 29, 2025, with no language restrictions. Studies were eligible if they defined and measured oral health equity among adults aged 45 and older. Two reviewers independently screened titles, abstracts, and full texts. Data were extracted on study characteristics, definitions of equity, measurement approaches, and aging-related equity interpretation. Results From 10,101 records (1976–2025), 25 studies met the inclusion criteria. Many framed health equity as a moral imperative tied to fairness and social justice, making it conceptually challenging to measure. To operationalize the concept, most studies adopted a horizontal equity approach, defining it as “equal care for equal need” and used the Horizontal Inequity Index and Concentration Index. Others applied methods such as out-of-pocket expenditure analysis, group comparisons of dental care utilization, or intersectionality-informed frameworks. Nearly all studies focused on dental care utilization; only two assessed inequity using oral health outcomes. Conclusion Despite the availability of established measurement tools, important gaps remain in how oral health equity is studied in aging populations. The dominance of service utilization outcomes highlights the need to explore other domains of (in)equity. Future research should engage with broader conceptual models of health equity and incorporate age-specific interpretations to better guide equity-oriented policy.