title: Dental, skeletal asymmetries and functional characteristics in Class II subdivision malocclusions.
abstract: Treatment outcomes of Angle Class II subdivision malocclusions may be compromised because of the uncertainty of the aetiology. Previous studies have reported controversial ideas about the origins, but the existence of a primary contributor still remains unknown. Functional factors have been mentioned as a probable cause, but until now, there have been no supporting data. This study was a cross-sectional investigation of the characteristics of Angle Class II subdivision malocclusion, including dental, skeletal and functional factors, by comparison of the subdivision group and the normal occlusion group. The evaluations of dental and skeletal asymmetries of both groups were carried out by cone-beam computed tomography (CBCT) and analysis of dental casts. The functional deviations were evaluated by cast mounting and measuring. In the subdivision group, the asymmetric position of the glenoid fossa was found to be the most significant skeletal asymmetry. No dentoalveolar asymmetry was found in this group. The most important finding was that, in subdivision malocclusions, functional deviation resulting in pseudoasymmetry occurred in 32.86% of the study participants. This deviation is probably related to the disharmonious arch width between maxillary and mandibular dental arches in the premolar section. The origin of Angle Class II subdivision malocclusion is multifactorial, with dental, skeletal and functional factors included. Functional deviation occurs, probably due to dental arch width disharmony. Asymmetric position of the glenoid fossa may account for most of the skeletal asymmetry.
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: T
authors.initials: T
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: H
authors.initials: H
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Xiang
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: C
authors.initials: C
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: X
authors.initials: X
authors.lastname: Han
authors.affiliation: State Key Laboratory of Oral Disease, West China School of Stomatology Sichuan University, Chengdu, China.
authors.forename: D
authors.initials: D
authors.lastname: Bai
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003430:Cross-Sectional Studies; D005147:Facial Bones / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008312:Malocclusion, Angle Class II / Q000000981:diagnostic imaging* / Q000503:physiopathology; D055815:Young Adult
keywords: centric relation; cone-beam computed tomography; craniofacial anomalies; dental occlusion; orthodontics; three-dimensional imaging