Short-term effects of reduced cost sharing on childhood dental care utilization and dental caries prevention in Japan

OBJECTIVES

Generous dental insurance coverage can improve oral health among children. However, most previous studies were from the United States, and the results may not be applicable to countries with universal healthcare systems. The purpose of the present study was to examine the effect of dental subsidy on dental service utilization and oral health among school-aged children.

METHODS

An administrative claims database in Kumamoto Prefecture, Japan, between 2014 and 2015 was used for the study. Municipalities in which the upper age limit of qualification for the dental subsidy was either 9 years of age or older were selected. The difference-in-differences approach was used to investigate the impact of subsidy discontinuation on dental care utilization and dental caries prevention. Dental care utilization was measured by number of first visits, number of total visits, and dental care cost per visit. Failure in dental caries prevention was determined by identifying treatment for acute severe dental conditions.

RESULTS

During the study period, 1108 eligible children made a total of 6276 visits to the 455 selected dental clinics. Among the dental clinics, 230 (50.5%) were located in municipalities in which the dental subsidy was discontinued when children reached age 10. After adjusting for area income and minimal user charges, there were no significant differences in subsequent dental care utilization (mean ratio 1.01, 95% confidence interval [CI] 0.97-1.04 for first visits; mean ratio 1.01, 95% CI 0.98-1.05 for total visits), acute severe dental conditions (mean ratio 1.06, 95% CI 0.90-1.24) or cost (coefficient 0.7 US dollars; 95%CI -0.2-1.6) during the 12-month period following the policy change.

CONCLUSION

The current dental subsidy policy may have limited value for promoting dental care utilization and improving oral health among school-aged children in Japan.