Reporting dental caries disease in longitudinal studies - a suggestion.

In general, most infectious and/or lifestyle-related diseases are defined as being present when sufficient signs or symptoms occurs in an individual. The term "sufficient".is a relative concept and a disease can therefore be measured with different degrees of certainty.These symptoms are commonly defined in such a way that it is possible to determine the incidence and prevalence of the disease and also the proportion of individuals that are cured from the dis- ease. If dental caries is an individual disease which can be compared to other diseases regarding incidence and prevalence, it is important to determine for how long an individual must be free from new signs of the disease before being considered cured or free from the disease and to define the "sufficient" signs or symptoms needed for a diagnose. Based on these thoughts, the purpose of this study was to calculate caries incidence and prevalence in a group of adolescents from a definition of dental caries based on ICD-1o. This study included all12 year olds in 1990 who attended a clinical dental examination in 1990-1995 in Orebro County, Orebro, Sweden, yearly during these six years. Dental caries disease at the individual level was defined as K02.1 (dentinal caries) according to ICD-io while freedom of caries was defined as the absence of K02.1 during a three-year period. In this study the yearly prevalence was 12%, the three year cu- mulative incidence was 18% and the incidence rate 13%. Results of this study highlight the poor outcomes in curing caries disease in this age-group, according to the criteria in this study, as only 17% of the children with caries at the outset of the study were free from the disease three years later. Defining both a practical level to measure signs of dental caries, and the period an individual must be free from them to be classified as cured from the disease create new oppor- tunities to compare and communicate the disease of dental caries with other diseases.This way of registration is also of advantage for planning purposes as there the centre of interest must be the individual patient and not the tooth or surface.