Variables under study

Treatment event outcomes were identified from the claims data for four dental diseases: stomatitis, tooth loss, dental caries/pulp disease, and gingivitis/periodontal disease. For the operational definition of outcomes, clinical opinions and definitions validated in previous studies were considered [14–16]. An event of treatment for stomatitis was defined as a case in which at least one claim was made with a relevant disease code. Events for tooth loss, dental caries/pulp disease, and gingivitis/periodontal disease were defined as cases in which at least one claim was made with a relevant disease code together with a disease-related treatment code. The relevant treatment codes for each disease were identified on the basis of the Health Insurance Medical Care report published by the Korean Health Insurance Review and Assessment Service (see Additional file 1: Table S1) [17]. The outcome of death was defined as a case in which beneficiaries lost their qualification due to death identified from the insurance eligibility data. Death was considered as a competing event for the outcomes of major dental treatment events.