title: A caries susceptibility classification of tooth surfaces by survival time.
abstract: Individual tooth surfaces have vastly different susceptibilities to caries and this susceptibility also varies over time. The aim of this study was to develop a method of grouping tooth surfaces into a caries susceptibility classification based on their survival experience. The data used in the study were from a 3-year caries clinical trial. The definition of survival time was taken to be the time from the start of the trial to when a surface is recorded as decayed or filled. Cluster analysis was used to divide the tooth surfaces into groups in such a way that surfaces in the same group have similar survival time distributions. The 13 groups identified were ordered from 1 to 13 starting with the group with the shortest survival time, i.e. the occlusal surfaces of the four first molars. Approximately 80% of symmetrical pairs of tooth surfaces were in the same group. The groups obtained using cluster analysis were compared to groups defined using dental/anatomical criteria. It is concluded that the cluster analysis method developed for grouping the tooth surfaces cn provide a useful descriptive measure of caries susceptibility which can be applied to data from any longitudinal study of caries.
authors.affiliation: Department of Mathematics and Statistics, University of Limerick, Ireland. ailish.hannigan@ul.ie
authors.forename: A
authors.initials: A
authors.lastname: Hannigan
authors.forename: D M
authors.initials: DM
authors.lastname: O'Mullane
authors.forename: D
authors.initials: D
authors.lastname: Barry
authors.forename: F
authors.initials: F
authors.lastname: Schäfer
authors.forename: A J
authors.initials: AJ
authors.lastname: Roberts
mesh_terms: D002648:Child; D016000:Cluster Analysis; D003731:Dental Caries / Q000145:classification* / Q000453:epidemiology; D003733:Dental Caries Susceptibility; D006801:Humans; D018709:Statistics, Nonparametric; D013499:Surface Properties; D016019:Survival Analysis; D013997:Time Factors; D016388:Tooth Loss / Q000453:epidemiology*; D014852:Wales / Q000453:epidemiology