title: Craniofacial growth in untreated skeletal Class I subjects with low, average, and high MP-SN angles: a longitudinal study.
abstract: Sixty-eight (36 male and 32 female) untreated skeletal Class I subjects with low (< or = 27 degrees ), average (>27 degrees - <37 degrees ), and high (> or = 37 degrees ) mandibular plane (MP-SN) angles were selected from the Bolton-Brush and Burlington Growth Studies. Cephalograms of each subject at ages 9 and 18 were traced, and 28 parameters were measured. The difference in each parameter from ages 9 to 18 was calculated, and comparisons were made between the groups with low, average, and high angles. Results showed that, for boys and girls at age 9, the low-angle groups exhibited significantly larger SNA angle, SNB angle, facial taper, PFH, PFH:AFH, and ramus height, and the high-angle groups showed significantly larger ANS-Me and gonial angle. From ages 9 to 18, all the male and female low-, average-, and high-angle groups showed an increase in SNA and SNB angles, and PFH:AFH, and a decrease in ANB angle, convexity (more flattened face), MP-SN angle, and gonial angle (mandibular forward rotation). The dental measurements showed few changes with growth in all groups. In terms of skeletal measurements from ages 9 to 18, similar growth changes were found between the sexes in most angular measurements, but males had larger values in linear measurements than females.
authors.affiliation: Department of Orthodontics, School of Dental Medicine, University of Pennsylvania, 4001 Spruce Street, Philadelphia, PA 19104-6003, USA. chunc@pobox.upenn.edu
authors.forename: Chun-Hsi
authors.initials: CH
authors.lastname: Chung
authors.forename: Vincent D
authors.initials: VD
authors.lastname: Mongiovi
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002508:Cephalometry; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008137:Longitudinal Studies; D008297:Male; D008311:Malocclusion, Angle Class I / Q000503:physiopathology*; D008445:Maxillofacial Development; D012727:Sex Characteristics; D012886:Skull / Q000254:growth & development*