ABSTRACT
Epidemiological studies to assess the prevalence and course of functional disturbances of the masticatory system should be based on a valid and reliable measure of the functional status of the masticatory system. NIELSEN et al. (2, 3) proposed a classification method that included three different classes of dysfunction. This classification was used to compare the results of a sample of 447 11-16-year-old Swiss adolescents with those of the Danish study and to test the validity of this classification method. The two studies showed similar prevalences in two of the three dysfunction classes and a similar pattern of dysfunction categories. Concurrent and construct validity analyses showed significant correlations between the assessment from clinical examination and the subjective judgments of the adolescents. The results demonstrated cross- and concurrent validation of the "Nielsen index" but also stressed the necessity of a careful re-evaluation of the "severe" class criterion. The limitations of the Nielsen index led to the construction of a "Zurich-MAP index". The potential applications of both indices are discussed.
