Validity of the self-reported number of teeth in Chilean adults

Clinical dental evaluations are considered complex and costly measurements that epidemiological surveillance studies of multiple simultaneous chronic diseases currently require, for example National Health Surveys (ENS). Accordingly, simpler and more affordable methods need to be validated. The aim of this study was to assess the validity of the self-report on the total number of teeth in the general Chilean adult population.

A substudy was conducted on ENS 2016-2017 participants. A stratified random sample of 101 of them was subjected to a telephone questionnaire. This information was then compared with the results obtained from the oral examination performed by a trained nurse during a home visit. Spearman correlations, intraclass correlation coefficients and the Bland-Altman method were used to analyse the data.

In men, the average number of teeth recorded during the oral examination coincided with the number of teeth in the self-report (22 teeth). In women, the total teeth average was 18 and 19 teeth according to the examination and self-report, respectively. For the total number of participants, a strong and significant Spearman correlation was obtained (ρ = 0.93); in men and women, the Spearman correlation observed was also strong and significant (ρ = 0.90 and ρ = 0.96 respectively). The value of the intraclass correlation coefficient indicated a significant concordance (CCI = 0.96) in both men and women (CCI = 0.93 and 0.98 respectively). A tendency to greater correlation was observed as the number of teeth decreased.

The number of teeth self-reported by the subjects in this study correlated with the number of teeth recorded in the clinical examination. Self-report is a valid method to determine the number of teeth in national health surveys.