Normative values for mandibular mobility in Scandinavian individuals 4-17 years of age

Assessment of mandibular mobility is an important part of the clinical oro-facial examination of paediatric and adolescent patients. The aims of the present cross-sectional study were to establish age-related normative values for mandibular mobility in a Scandinavian paediatric and adolescent cohort and to assess the validity of universal cut-off values for lower 'normal' mandibular ranges of motion. A total of 1114 Danish individuals between 4-17 years of age were included. Maximal mouth opening capacity and laterotrusion capacity were assessed, in each individual, according to a standardised measurement protocol. The mean maximal mouth opening capacity gradually increased from 38 mm (SD 6.1 mm) at age 4 to 54.5 mm (SD 6.8 mm) at age 17. No inter-gender difference in maximal mouth opening capacity was observed (P > 0.15). The mean maximal laterotrusion capacity gradually increased from 7.4 mm (SD. 1.1 mm) at age four to 10.1 mm (SD 1.9 mm) at age 17. A statistical significant inter-gender difference of 0.8 mm (SD 0.4 mm) was observed in relation to the total laterotrusion capacity; however, the clinical relevance of this significant difference is questionable. Normative values of mandibular function was established in individuals 4-17 years of age. Our findings oppose the use of a single universal cut-off value for 'normal' range of motion in paediatric and adolescent patients. Instead, we recommend to use the age-related normative values of mandibular range of motion as basis for the assessment of the development of oro-facial function.