Caries on permanent teeth: A nonparametric Bayesian analysis

Most earlier epidemiological investigations of dental caries have been base d on cross-sectional data. Subject-specific information of dental caries in the past, and the duration of exposure of each tooth to the oral environme nt, are obviously important factors also influencing the presence of dental caries in the future. This has led us to consider multivariate survival mo dels in which the information about the tooth eruption and failure times ar e combined to assess caries risk. A non-parametric Bayesian intensity model is presented, reflecting, on the one hand, the within subject and between subject sources of variability, and a corresponding split of variability wh en considering the 28 permanent teeth. We analyse a data set consisting of the dental history of 240 boys, where the observations are based on predete rmined dental examinations taking place approximately once every year. Mark ov chain Monte Carlo integration techniques are applied in the numerical wo rk.