Clinical classification of periodontitis in adolescents and young adults.

THE AIM OF THIS STUDY was to determine the degree to which clinical classifications based on cross-sectional assessments endure in the course of development of early-onset periodontitis (EOP), and to introduce new criteria which might improve the clinical classification of these diseases. Subjects with EOP and a matched group without EOP were identified within a national probability sample examined during the 1986/87 survey of US schoolchildren. Of these, 265 subjects (mean age 16 years) were re-examined during the 1992/93 school year. The clinical attachment level of teeth was assessed, and the individuals were classified into localized juvenile periodontitis (LJP), generalized juvenile periodontitis (GJP), incidental attachment loss (IAL), and no-periodontitis groups using three classification methods previously described. A fourth method that considered the extent and severity of attachment loss and the number of missing teeth was introduced to classify the individuals at baseline and at follow-up as having localized, generalized, or incidental EOP, and no-periodontitis groups. Furthermore, the individuals were classified using criteria based on the rate and pattern of change in attachment loss during 6 years. The results showed low correlations between the baseline classifications and the classifications at the 6-year follow-up examination, irrespective of the method used. In addition, the cross-sectional classifications were not predictive of the rate of progression of periodontal disease in these subjects. In the generalized disease group, two-thirds of the individuals exhibited moderate/rapid disease progression, while one-third had slow or no progression. In the localized disease group, one-half of the individuals had moderate/rapid disease progression and one-half had slow or no progression. In the incidental disease group one-fourth of the individuals had moderate/rapid disease progression and three-fourths had slow or no progression. We propose that the term early-onset periodontitis be used as a generic term to describe periodontal disease before its normal onset. In addition, we suggest that incidental, localized, and generalized EOP are heterogenous groups comprising rapidly and slowly progressing forms within each classification. The findings suggest that a classification system in which subsets of the disease that are defined according to a combination of cross-sectional criteria and the disease progression may be useful in studies of EOP. Furthermore, the findings suggest that clinical classifications of EOP be used as generic descriptors until a full understanding of the pathogenesis of this disease is accomplished.