A study of the growth changes in the maxillofacial skeleton of females with reversed occlusion: investigation by means of lateral x-ray cephalogram.
321 females with reversed occlusion from the ages of 6 to 20 were classified into 15 groups according to chronological age, and the changes of maxillofacial skeleton accompanying growth were investigated. Lateral cephalometric roentgenogram before treatment of the subjects were used for analyses and measurements of maxillofacial skeleton and overjet. The cephalometric analysis was standardized on the S-N plane, and 5 angular items and 6 linear distances were examined. The results of the investigation are summarized as follows: (1) angle ANB, the relationship between the upper and lower jaws, deteriorated to a minus degree from the age of 9 and became -3.3 degrees at the age of 14. Skeletal convexity became negative from the same age and was -7.3 degrees at the age of 14. Thus, the abnormal skeletal features progressed in this condition. (2) The Ar-Gn distance measurement gradually increased from the age of 6 to 18. The increase was 16.2 mm from 7 to 12, an increase of 3.2 mm yearly. (3) A high correlation (r = 0.99) was observed between angle ANB and Convexity. As well, a high coefficient of correlation (r = 0.87) was observed between skeletal convexity and soft tissue convexity. The change in soft tissue convexity may occur 3-4 years later than that of skeletal convexity. (4) The growth curve of Ar-Gn became a logistic curve with the point of deflection at the age of 10.87. The growth curves of S-Gn and N-Me became logistic curves in the same way.
Yamaguchi
H
H
Department of Orthodontics, Tokyo Dental College, Chiba, Japan.
Naruse
T
T
Lin
M H
MH
Nakakawaji
K
K
Katada
H
H
Isshiki
Y
Y
D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D005260:Female; D006801:Humans; D016015:Logistic Models; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008445:Maxillofacial Development; D011859:Radiography; D012727:Sex Characteristics