Inequalities in Dental Service Utilization among Thai Adults from 2000 to 2017.

OBJECTIVES:The Universal Coverage Health Scheme (UCS) was implemented in Thailand in 2002 to increase access to health services among the Thai population. This study aimed to evaluate socioeconomic inequalities in dental service utilization (DU) before and after UCS implementation and to assess factors associated with DU among Thai adults.METHODS:This study is based on secondary data from four Thai national oral health surveys in 2000-2001, 2006-2007, 2012 and 2017. Whether an individual from a nationally representative sample of Thai adults aged 35-44 went to see the dentist during the past year was used to define DU. The slope index of inequality (SII) and relative index of inequality (RII) were used to assess and compare education and income-related inequalities in DU. Poisson regression was used to assess factors associated with DU. Income inequalities were not reported for the year 2001 (Income data not available).RESULTS:Although DU increased after UCS implementation, socioeconomic inequalities persisted. DU was concentrated among high-education and income groups. Absolute educational inequalities were 0.16 (95% CI: 0.09-0.22), 0.21 (95% CI: 0.10-0.32), 0.26 (95% CI: 0.14-0.38) and 0.25 (95% CI: 0.18-0.32) in 2001, 2007, 2012 and 2017, respectively. Absolute income inequalities were 0.15 (95% CI: 0.04-0.26), 0.07 (95% CI: -0.04-0.18) and 0.12 (95% CI: 0.05-0.19) in 2007, 2012 and 2017, respectively. Occupation, type of health insurance scheme, sex and oral health-related behaviour were associated with DU.CONCLUSION:UCS has improved accessibility to dental services, but UCS alone might not narrow the inequalities gap for Thai adults.