Abstract
Background:
Scientific equity requires research that reflects the full population diversity. Although the United States and international laws prohibit discrimination based on age, sex, race, and disability in health care and research, whether these protections have reduced bias in dental publications remains unclear.

Aim:
This study evaluates demographic representation in the dental literature relative to the distribution of the United States population.

Methods:
A bibliometric analysis was conducted of all MEDLINE-indexed dental publications containing descriptors for age, sex, race, sex, poverty, or disability. To minimize the risk of selection bias, all retrieved records were analyzed in accordance with PRISMA 2020 guidelines. Representation was quantified as the proportion of publications referencing each demographic group and compared with the corresponding national census data. Chi-square tests were applied at a significance threshold of P < 0.05.

Results:
The dental research literature revealed substantial and persistent underrepresentation of older adults, some racial minority populations, and individuals with disabilities. Relative to their population share, older adults were underrepresented by 77%, American Indian and Alaska Native groups by 78%, and individuals with disability experienced the greatest underrepresentation at 86%. These disparities were most concentrated in the treatment and diagnostic studies.

Conclusion:
Underrepresentation based on age, race, and disability remains widespread in dental research despite the legal and ethical safeguards intended to prevent exclusion.

Key words: Disparities; Exclusion; Inclusion; Treatment; Underrepresentation.