Growth changes in the cranial base and the face: a longitudinal cephalometric study of linear and angular changes in adult Norwegians.

The purpose of this study was to examine the natural growth changes which occur between 22 and 33 years of age. The material consisted of two series of cephalograms of 74 females and 90 males with approximately 11 years between the two series. None of the subjects had orthodontic retainers when the first exposure was undertaken, or orthodontic treatment, or surgery during the observation period. The measurements were carried out by using a modified Dentofacial Planner program SHORT, and both linear and angular measurements were made. The overall changes were an increase in anterior facial height which mostly occurred in the lower face, and an increase in the length of the mandible. These changes were statistically significant in both genders. The females also had a significant posterior rotation of the mandible. There was a significant decrease in the thickness of the upper lip both in females and males, and the males had a significant increase in thickness of the soft tissue on the mandibular profile. Although there were some statistical changes in the observation period, none of the linear changes exceeded 1.35 mm. The largest angular change was a 1.44 degrees retroclination of the upper incisors in females. The differences between the genders were statistically significant only in three angular and two soft tissue measurements.