What is intersectionality and why is it important in oral health research?

This paper is the second of two reviews that seek to stimulate debate on new and neglected avenues in oral health research. The first commissioned narrative review, "Inclusion oral health: Advancing a theoretical framework for policy, research and practice", published in February 2020, explored social exclusion, othering and intersectionality. In it, we argued that people who experience social exclusion face a "triple threat": they are separated from mainstream society, stigmatized by the dental profession, and severed from wider health and social care systems because of the disconnection between oral health and general health. We proposed a definition of inclusion oral health and a theoretical framework to advance the policy, research and practice agenda. This second review delves further into the concept of intersectionality, arguing that individuals who are socially excluded experience multiple forms of discrimination, stigma and disadvantage that reflect intersecting social identities. We first provide a theoretical and historical overview of intersectionality, rooted in Black feminist ideologies in the United States. Our working definition of intersectionality, requiring the simultaneous appreciation of multiple social identities, an examination of power and inequality, and a recognition of changing social contexts, then sets the scene for examining existing applications of intersectionality in oral health research. A critique of the sparse application of intersectionality in oral health research highlights missed opportunities and shortcomings related to paradigmatic and epistemological differences, a lack of robust theoretically engaged quantitative and mixed methods research, and a failure to sufficiently consider power from an intersectionality perspective. The final section proposes a framework to guide future oral health research that embraces an intersectionality agenda consisting of descriptive research to deepen our understanding of intersectionality, and transformative research to tackle social injustice and inequities through participatory research and co-production.