Abstract
<title>Abstract</title> <p>Background Neighborhood social vulnerability may influence oral health through socioeconomic disadvantage and barriers to care, yet evidence at the census-tract level remains limited, and the independent contributions of different dimensions of social vulnerability remain poorly understood. We examined the association between the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry (CDC/ATSDR) Social Vulnerability Index (SVI) and two tract-level oral health outcomes across California census tracts. Methods We conducted a cross-sectional ecological study of 9,019 California census tracts representing 39.2 million residents. Tract-level 2022 SVI data were linked to CDC PLACES estimates of edentulism among adults aged ≥ 65 years and past-year dental visits among adults aged ≥ 18 years. Census tracts with populations below 500 were excluded. Associations were estimated using fractional logistic regression with county-clustered standard errors. The four SVI domains were evaluated in mutually adjusted models, and robustness was assessed using the Area Deprivation Index, Social Deprivation Index, and independent county-level estimates from the California Health Interview Survey. Results Each 0.10-unit increase in SVI was associated with 20% higher odds of edentulism (odds ratio [OR], 1.195; 95% confidence interval [CI], 1.183–1.207) and 13% lower odds of a past-year dental visit (OR, 0.873; 95% CI, 0.868–0.877). A monotonic dose-response relationship was observed across SVI quartiles: edentulism increased from 5.6% in the least vulnerable quartile to 18.1% in the most vulnerable quartile, whereas past-year dental visits declined from 72.4% to 48.8%. Socioeconomic status demonstrated the strongest independent association with both outcomes, whereas the minority status and language domain remained independently associated with dental visits but not edentulism. Findings were robust across alternative disadvantage indices and independent survey estimates. Conclusions Higher neighborhood social vulnerability was strongly associated with both edentulism and dental care utilization across California census tracts. Tract-level analyses identified socioeconomic vulnerability as the dominant dimension associated with oral health disparities and revealed geographic patterns that may not be apparent in county-level analyses. These findings support the use of tract-level social vulnerability measures to guide more equitable allocation of preventive and clinical dental resources. Trial registration Not applicable. This study used publicly available, de-identified data and did not involve human participants.</p>