Dentofacial changes in adults: a longitudinal cephalometric study in 22-33 and 33-43 year olds.
OBJECTIVE
The purpose of the present study was to analyze sagittal and vertical cephalometric changes in 41 men and 52 women from 22-43 years of age and to examine differences between the periods 22-33 years (T1-T2) and 33-43 years (T2-T3) as well as gender differences in the changes during the two periods.


METHODS
Our study data derived from three cephalograms of each individual. Very few subjects had undergone orthodontic treatment in childhood, and none had used retainers during the 5 years before the first cephalogram (T1). Neither had any undergone orthodontic treatment or orthognathic surgery during the observation periods. All cephalograms were taken with the same cephalostat, and all subjects were aged between 20 and 26 years, with a mean age of 22.6 and 22.5 years for women and men, respectively, when the first cephalogram was taken. The measurements were taken using a modified Dentofacial Planner SHORT software program.


RESULTS
At 22 years of age, all linear parameters (S-N, N-Me, S-tGo, Co-Me, Ar-Me) were larger in men. Of the anteroposterior parameters, S-N increased more in women, while Co-Gn and Ar-Gn increased more in men. This increase was largest in the first period in both genders. The vertical N-Me increased in both genders in both periods, but more in the women. The posterior S-tGo increased more in men in both periods. The lower parts of the vertical parameters increased more than the upper parts. The ML-NSL angle increased during both periods in women, while in men no statistically significant change was revealed. The S-N-A angle decreased in both genders in the first period and continued to decrease in the second in women, while in men an increase in the second period was demonstrated. Angles related to the anteroposterior position of the mandible (S-N-B and S-N-Po) decreased during both periods in women while the angles in men did not change. The incisors retroclined during both periods in both genders. Overall changes were larger in the first period than in the second.


CONCLUSIONS
Changes of the human facial skeleton continue in the third and forth decade of life and are significant. However, the mandibular growth rate decreases between the third and fourth decade. Men generally have a larger anterior cranial base and a larger face. These gender differences continue to increase with advanced age. The sagittal position of the jaw bases became more retrognathic in women. The reason for the altered mandibular position is also a posterior rotation of the lower jaw. In men, the mandibular inclination remains more stable.
Dental Faculty, Department of Orthodontics, University of Oslo, Norway. olav.bondevik@odont.uio.no
Olav
O
Bondevik
D000328:Adult; D000375:Aging / Q000502:physiology*; D002508:Cephalometry / Q000379:methods*; D005147:Facial Bones / Q000254:growth & development; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007574:Jaw Relation Record; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000175:diagnosis*; D008334:Mandible / Q000254:growth & development; D008437:Maxilla / Q000254:growth & development; D012016:Reference Values; D012737:Sex Factors; D019291:Skull Base / Q000254:growth & development; D012984:Software; D055815:Young Adult