Use of the dental formula from the National Database of Health Insurance Claims and Specific Health Checkups of Japan

The National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) is a database including health insurance claim and specific health checkup data. Observational studies using real-world big data attract attention because they have certain strengths, including external validity and a large sample size. This review focused on research using the dental formula of the NDB because the number of teeth is an important indicator of oral health. The number of teeth present calculated using the dental formula of periodontitis patients was similar to that from the Survey of Dental Diseases. In addition, the graphs of the presence rates of tooth types by 5-year age groups from the NDB were smoother and had less overlap than those from the Survey of Dental Diseases, and they could detect slight changes in the presence rate that reflected sugar consumption before and after World War II. Using the NDB, a low number of teeth was associated with high medical care expenditures, high risk of aspiration pneumonia, and high risk of Alzheimer’s disease. Although there are some restrictions on the use of the NDB, we hope that dental research using the NDB will be further promoted in the future.