[Equity and spatial distribution evolution of dentist resources in China (2012-2023) with trend prediction]

Objective: To analyze the changes and spatial distribution characteristics of dentist resource allocation in China from 2012 to 2023, thereby providing a basis for optimizing the allocation of oral health workforce. Methods: Based on panel data from 31 provincial-level administrative regions in China from 2012 to 2023, the Gini coefficient (G) and Theil index (T) were used to evaluate the equity of dentist distribution. Global and local spatial autocorrelation analyses were conducted to examine the spatial distribution of dentist resources, and a geodetector was employed to explore the influencing factors. Based on grey prediction model (GM) theory, the first-order univariate differential equation model [GM(1, 1)] was applied to project the allocation patterns of dentists in China for 2030 and 2035. Results: The total number of dentists increased from 116.2 thousand in 2012 to 387.4 thousand in 2023, with an average annual growth rate of 11.6%. In 2023, the proportions of female dentists, those with 10 years of work experience, those with a bachelor's degree or above, and those with junior/assistant professional titles were 54.3% (210.3 thousand), 49.9% (193.3 thousand), 45.3% (175.5 thousand), and 51.6% (199.9 thousand), respectively. The dentist-to-population ratio in 2023 was 2.75 per 10 000 population, meeting the World Health Organization recommended basic standard (2 per 10 000) while remaining lower than the level of upper-middle-income countries (4.04 per 10 000). In 2023, the distribution of dentists by population was absolutely equitable (G=0.169, T=0.049), as was the distribution by gross regional product (G=0.174, T=0.053), whereas the distribution by geographic area was highly inequitable (G=0.699, T=0.955). Global Moran's I increased progressively (0.207 in 2012, 0.220 in 2016, 0.270 in 2019, and 0.397 in 2023), and statistical tests indicated that the Global Moran's I value for each year was significantly greater than 0 (all P0.05), suggesting the presence of significant positive spatial autocorrelation. The spatial extents of both "high-high" clusters and "low-low" clusters expanded at each subsequent time point. In 2023, "high-high" clusters were mainly concentrated in North China and its adjacent provincial-level administrative regions, whereas "low-low" clusters were located primarily in the Southwest and adjacent parts of the Central South and Northwest regions. Year-end resident population, gross regional product, local health expenditure, number of colleges offering dentistry undergraduate programs, number of hospitals, and outpatient and emergency visits to hospital dental departments were the main factors influencing the spatial distribution of dentists, with independent q values of 0.770, 0.776, 0.764, 0.661, 0.607, and 0.680, respectively, all of which were tested to be significantly greater than 0 (all P0.05); moreover, the interaction effect of any two factors was greater than their respective independent effects. Projections indicate that the dentist-to-population ratio will reach 5.88 per 10 000 in 2030 and 10.26 per 10 000 in 2035, with regional disparities continuing to intensify. The Southwest region, especially Xizang, will persist as the most pronounced underserved area. Conclusions: The number of dentists in China increased year by year from 2012 to 2023, yet structural imbalances and geographical inequities persisted. Their spatial distribution was influenced by multiple factors, with spatial clustering progressively intensified. Projections suggest that regional disparities in dentist distribution may further widen. Therefore, future policies should aim to expand the total number of dentists while simultaneously optimizing its structure and promoting regional balance.