Mandibular jaw movement capacity in 10-17-yr-old children and adolescents:: normative values and the influence of gender, age, and temporomandibular disorders

The aims of this study were, first, to report normative values for jaw movements in Caucasian children and adolescents (maximum opening, laterotrusion, and protrusion) and, second, to investigate the influence of age, gender, and temporomandibular disorders (TMD) on jaw movement capacity. The population-based study included 1,011 randomly selected German children and adolescents, aged 10-17 yr. Case histories, as well as mandibular movements and the presence of TMD, were assessed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The mean +/- standard deviation for maximum opening was 50.6 +/- 6.4 mm, for laterotrusion to the right was 10.2 +/- 2.2 mm, for laterotrusion to the left was 10.6 +/- 2.3 mm, and for protrusion was 8.2 +/- 2.5 mm. Bivariable (t-test) and multivariable (linear regression) analyses showed that normative values for jaw opening capacity were influenced by age and gender. No influence on jaw movement capacity was seen when TMD were present. Based on the distribution of the measurements in the population (lowest decentile), the mandibular mobility of subjects with a maximum opening of < 43 mm and laterotrusive movements < 8 mm or protrusive movements < 5 mm might be considered as being limited. However, these limitations do not necessarily require treatment.