Correcting for misclassification for a monotone disease process with an application in dental research.

Motivated by a longitudinal oral health study, we evaluate the performance of binary Markov models in which the response variable is subject to an unconstrained misclassification process and follows a monotone or progressive behavior. Theoretical and empirical arguments show that the simple version of the model can be used to estimate the prevalence, incidences, and misclassification parameters without the need of external information and that the incidence estimators associated with the model outperformed approaches previously proposed in the literature. We propose an extension of the simple version of the binary Markov model to describe the relationship between the covariates and the prevalence and incidence allowing for different classifiers. We implemented a Bayesian version of the extended model and show that, under the settings of our motivating example, the parameters can be estimated without any external information. Finally, the analyses of the motivating problem are presented.

Factors that influence data quality in caries experience detection: a multilevel modeling approach.

Caries experience detection is prone to misclassification. For this reason, calibration exercises which aim at assessing and improving the scoring behavior of dental raters are organized. During a calibration exercise, a sample of children is examined by the benchmark scorer and the dental examiners. This produces a 2 × 2 contingency table with the true and possibly misclassified responses. The entries in this misclassification table allow to estimate the sensitivity and the specificity of the raters. However, in many dental studies, the uncertainty with which sensitivity and specificity are estimated is not expressed. Further, caries experience data have a hierarchical structure since the data are recorded for the surfaces nested in the teeth within the mouth. Therefore, it is important to report the uncertainty using confidence intervals and to take the clustering into account. Here we apply a Bayesian logistic multilevel model for estimating the sensitivity and specificity. The main goal of this research is to find the factors that influence the true scoring of caries experience accounting for the hierarchical structure in the data. In our analysis, we show that the dentition type and tooth or surface type affect the quality of caries experience detection.

Caries patterns in primary dentition in 3-, 5- and 7-year-old children: spatial correlation and preventive consequences.

This study aimed to contribute to the descriptive information of oral health status in the primary dentition, especially concerning the distribution and spatial correlation of lesions. Data were obtained from two surveys. In the Signal-Tandmobiel project 4,468 7-year-old children in Flanders (Belgium) were selected by a stratified clustered random sample. In the Tandje de Voorste - Smile for Life (TDV) project, data were obtained from 1,291 3-year-old and 1,315 5-year-old children. The children were examined by trained dentists, using standardized and widely accepted criteria, based on the British Association for the Study of Community Dentistry criteria. At the population level, symmetry in the prevalence of caries experience across the midline was tested at the tooth and tooth surface levels using generalized estimating equations and alternating logistic regression (ALR) approaches. Individual symmetry was tested using an approach described by Hujoel et al. [J Dent Res 1994;73:1575-1580]. Descriptive observations suggested a symmetrical distribution of caries experience at the population level. The null hypothesis of symmetry could not be rejected at a 0.05 level, suggesting that caries experience might be symmetric in the deciduous dentition. Based on the ALR approach, 2 x 2 associations of caries experience at the tooth and surface levels, both in 5- and 7-year-olds, appeared to be strongest for the left-right pairs in the mandible, followed by the left-right pairs in the maxilla. At the individual level the hypothesis of random caries pattern was rejected (p < 0.0001). In conclusion, at the population level the null hypothesis of left-right symmetry could not be rejected, while at the individual level lesions tended to cluster on one side of the mouth.