Factors associated with development of root caries in dentition without root caries experience in a 2-year cohort study in Japan.

OBJECTIVES: To investigate factors associated with the development of root caries in dentition without root caries experience and interactive relationships between risk factors. METHODS: We conducted surveys, consisting of an oral examination (oral hygiene, assessment of the number of teeth, coronal and root caries) and a self-reported questionnaire, among employees of a company in Tokyo, Japan in 2016 and 2018. Questionnaires collected data on smoking status, oral hygiene habits, sugar intake, and frequency of dental visits. Multiple logistic regression and decision tree analyses were used to determine factors associated with the development of root caries. RESULTS: A total of 299 participants aged 25-63 years were included in the analysis. Males, older adults, smokers/past smokers had a significantly greater risk of developing root caries. The risk of developing root caries was significantly associated with the number of teeth with gingival recession at baseline (6-9 teeth, odds ratio [OR]: 7.69, 95 % confidence interval [CI]: 2.31-25.56; 10+ teeth, OR: 9.19, 95 % CI: 2.73-30.95, relative to </=5 teeth); and with the number of coronal decayed and filled (DF) teeth (11-13 teeth, OR: 3.21, 95 % CI: 1.12-9.24; and >/=14 teeth, OR: 3.60, 95 % CI: 1.27-10.20, relative to </=10 teeth). Other factors associated with root caries development differed according to the number of teeth with gingival recession and included drinking sugar-sweetened beverages, and the amount of toothpaste used. CONCLUSIONS: Gingival recession and number of coronal DF teeth were associated with the development of root caries. CLINICAL SIGNIFICANCE: Multiple factors are associated with root caries development. The effect of risk factors such as drinking sweetened beverages and less toothpaste use is greater in individuals with greater gingival recession and more coronal decayed and filled teeth. Dental practitioners should focus on modifiable risk factors to prevent root caries.