Evaluation of the normal range of vertical mandibular opening in children and adolescents with special reference to age and stature.

1050 subjects between 5 and 19 years of age were examined to determine the normal range of values for maximum vertical mandibular opening and incisal edge distance. As a result of subsequent statistical evaluation, it can be stated that mouth opening depends to a significant extent upon age and stature. For the determination of "normal" mandi opening, the minimal value using incisal edge distance is 35 mm for 5-to 10-year-old children and 38 mm for 11- to 19-year olds. The corresponding values for alveolar crest distance is 44 mm and 49 mm. Determination of "normal" mandibular opening using the alveolar crest distance seems superior to that of incisor edge distance and should be recommended for universal use in general practice.