Arch widths in class II-2 adults compared to adults with class II-1 and normal occlusion.
OBJECTIVE
To compare (1) arch widths in adults with Class II division 2 (II-2), Class II division 1 (II-1), and Class I normal occlusions, (2) genders, (3) gender dimorphism, (4) differences between maxillary and mandibular arch widths, and to (5) develop adult norms for arch widths.


METHODS
Subjects were white Americans with no history of orthodontic treatment. Arch width dimensions measured were: intercanine, intermolar, and molar alveolar in both arches. Analysis of variance (ANOVA) and Duncan's test were used to compare groups.


RESULTS
Comparison of pooled genders showed the II-2 group had maxillary arch widths significantly smaller than the normal occlusions and significantly larger than the II-1 group. All groups had similar mandibular intercanine and alveolar widths. The II-2 and II-1 groups had similar mandibular intermolar widths, both significantly smaller than normal occlusions. The II-2 group had a maxillary/mandibular intermolar difference significantly smaller than the normal occlusions, and significantly less negative than the II-1 group. Gender comparisons in two of six widths showed normal and II-2 male subjects were similar, and in six of six widths normal and II-2 female subjects were similar; in five of six widths II-2 and II-1 male and female subjects were similar. Gender dimorphism occurred in five of six widths in normal occlusions, four of six widths in II-2, and one of six widths in II-1.


CONCLUSIONS
Arch width dimensions of II-2 subjects were intermediate between normal and II-1 occlusions. In both Class II malocclusions, the process that narrows arch widths was more pronounced in male than in female subjects.
Department of Orthodontics, College of Dentistry, University of Iowa, Iowa City 52242, USA.
Joel
J
Huth
Robert Newton
RN
Staley
Richard
R
Jacobs
Harold
H
Bigelow
Jane
J
Jakobsen
D000293:Adolescent; D000704:Analysis of Variance; D003724:Dental Arch / Q000473:pathology*; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D008297:Male; D008311:Malocclusion, Angle Class I / Q000473:pathology*; D008312:Malocclusion, Angle Class II / Q000145:classification / Q000473:pathology*; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D012727:Sex Characteristics