Rater Reliability for Assessing DMFT in 12 Year-Old Children in Primary School

Abstract

The World Health Organization (WHO) has developed important new methods for assessing oral health. It is important to determine which measurement methods need to be included as data on inter-rater and intra-rater reliability as revealed by oral examinations and duplicate oral examinations conducted during the course of surveys. The objective of this study was to describe the use of the intra-class correlation coefficient (ICC) models for assessing Decayed, Missing, and Filled Teeth (DMFT) in 12 year-old children in primary school. The inter-rater reliability method, which was developed by a gold standard dentist and the researcher, was utilized with oral examinations in the same 50 students under the WHO criteria and calibrated before oral examinations. The students were blindly chosen by the teacher, who had assigned the children to have oral examinations with the two raters. The intra-rater reliability method, which was developed by the researcher, duplicated oral examinations for same 47 students after the inter-rater reliability assessment in the next week by using the same oral health complied form. Data on the Decayed, Missing, and Filled Teeth (DMFT) was employed to measure as the count data. In addition, the intra-class correlation coefficient was measured, including the 95% confidence interval (95%CI), which presented magnitudes of the mixed-effect model and the random effect model. The mixed-effect model showed inter-rater reliability in assessing Decayed, Missing, and Filled Teeth and DMFT equal to 0.93 (95%CI: 0.89 - 0.96), 0.00 (95%CI: -0.76 - 0.43), 0.95 (95%CI: 0.91 - 0.97), and 0.95 (95%CI: 0.91 - 0.97), respectively. The random-effect model showed intra-rater reliability in assessing decayed, missing, and filled teeth and a DMFT equal to 0.94 (95%CI: 0.88 - 0.96), 0.00 (95%CI: -0.79 - 0.44), 0.88 (95%CI: 0.79 - 0.94), and 0.96 (95%CI: 0.92 - 0.97), respectively. The mixed-effect model and random-effect model showed excellent inter-rater and intra-rater reliability. The results showed the variance of missing teeth to be zero. As a result, the correlation index was able to be interpreted in terms of rater consistency rather than rater agreement.