CHARACTERISTICS OF PROTRUSIVE AND LATERAL EXCURSIONS OF THE MANDIBLE IN CHILDREN WITH THE PRIMARY DENTITION

This study characterizes the mandibular protrusive and lateral excursi ons of children with primary dentition. With use of a Selspot(R) syste m, the protrusive and lateral excursions of nine children with the pri mary dentition and nine adults with the permanent dentition were measu red and compared. This system was able to analyse the simultaneous mov ements of multiple points on the mandible of a subject in three dimens ions. Furthermore, the system proved appropriate for use in young chil dren because of the small burden imposed on them during the measuremen ts. Using this subject-friendly system, the directions of the mandibul ar excursion for five reference points on the mandibular dental arch a t each measurement distance (i.e. at 0.5 mm intervals) for three proje cted angles (frontal, sagittal and horizontal) were calculated. From t he results it was found that the excursions of the primary dentition c an move more horizontally and more forward with small descent compared with the permanent dentition. The underlying reason for these finding s may be physiological growth, maturation, and adaptation of the occlu sal function.