Decomposition of economic inequalities in dental caries among Iranian schoolchildren

Introduction: Monitoring social inequalities in dental caries is crucial for establishing priorities in oral health systems. This study aimed to assess economic inequalities in dental caries and its contributing factors among Iranian schoolchildren. Methods: Data were obtained from the first phase of the Shahroud Schoolchildren Eye Cohort Study in 2015. A total of 4992 children aged 6–12 years old were included in the analysis. Dental examinations were conducted following the diagnostic methods and standards of the Oral Health Examination Survey, as recommended by the World Health Organization. The concentration index (C) was utilized to assess economic inequalities in dental caries. Additionally, the decomposition of C was employed to explain the determinants of the measured inequalities. Results: In total, 71.4% of the schoolchildren had dental caries in primary dentition (dft≥1), and 41.6% of the schoolchildren had dental caries in permanent dentition (DMFT≥1). The Cs of dft≥1, primary decayed teeth (pdt≥1), and permanent missing teeth (PMT≥1) were -0.136 (95% CI: -0.167, -0.104), -0.164 (95% CI: -0.194, -0.134), and -0.208 (95% CI: -0.262, -0.153), respectively, which indicates their more concentration among low-economic children. Conversely, pft≥1 and PFT≥1 had Cs of 0.327 (95% CI: 0.292, 0.361) and 0.218 (95% CI: 0.179, 0.256), showing more concentration among high-economic children. Basic health insurance coverage and age were the main contributors that explained 28.6% and 19.2% of the economic inequality in dft≥1, and 25.7% and 16.6% of the pdt≥1 inequality, respectively. Economic status, residence in rural areas, mother education, father education, and age were the main contributors to the measured inequality in pft≥1 by 80.5% and 26.5%, 21.9%, 22%, and -18.3%, respectively. Economic status, having a housekeeper mother, residence in rural areas, having basic health insurance coverage, mother education, and father education positively contributed to the measured inequality in PMT≥1 by 45.4%, 42.4%, 37.8%, 35.1%, 21.3%, and 15.2%, respectively, while age had a negative contribution of -19.3%. For PFT≥1, economic status, age, and father education accounted for 76%, 25.4%, and 20.3% of the measured inequality, respectively. Conclusion: Pro-rich economic inequalities were observed in children’s primary and permanent teeth caries. Thus, government interventions to reduce these inequalities should aim to expand the coverage of basic and supplementary health insurance in line with increasing the coverage of dental health costs in these plans, training and providing access to required dental health services for low-socioeconomic children, including the poor, rural, and those who have low-educated parents and a housekeeper mother, especially at younger ages.