title: Cone-Beam Computed Tomography Assessment of Lower Facial Asymmetry in Unilateral Cleft Lip and Palate and Non-Cleft Patients with Class III Skeletal Relationship.
abstract: BACKGROUND
  To evaluate, using cone-beam computed tomography (CBCT), both the condylar-fossa relationships and the mandibular and condylar asymmetries between unilateral cleft lip and palate (UCLP) patients and non-cleft patients with class III skeletal relationship, and to investigate the factors of asymmetry contributing to chin deviation.
  
  
  METHODS
  The UCLP and non-cleft groups consisted of 30 and 40 subjects, respectively, in mixed dentition with class III skeletal relationships. Condylar-fossa relationships and the dimensional and positional asymmetries of the condyles and mandibles were examined using CBCT. Intra-group differences were compared between two sides in both groups using a paired t-test. Furthermore, correlations between each measurement and chin deviation were assessed.
  
  
  RESULTS
  It was observed that 90% of UCLP and 67.5% of non-cleft subjects had both condyles centered, and no significant asymmetry was found. The axial angle and the condylar center distances to the midsagittal plane were significantly greater on the cleft side than on the non-cleft side (P=0.001 and P=0.028, respectively) and were positively correlated with chin deviation in the UCLP group. Except for a larger gonial angle on the cleft side, the two groups presented with consistent asymmetries showing shorter mandibular bodies and total mandibular lengths on the cleft (deviated) side. The average chin deviation was 1.63 mm to the cleft side, and the average absolute chin deviation was significantly greater in the UCLP group than in the non-cleft group (P=0.037).
  
  
  CONCLUSIONS
  Compared with non-cleft subjects with similar class III skeletal relationships, the subjects with UCLP showed more severe lower facial asymmetry. The subjects with UCLP presented with more asymmetrical positions and rotations of the condyles on axial slices, which were positively correlated with chin deviation.
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Gui
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Fu
authors.affiliation: Department of Oral Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Weiran
authors.initials: W
authors.lastname: Li
mesh_terms: D002648:Child; D002971:Cleft Lip / Q000000981:diagnostic imaging* / Q000473:pathology; D002972:Cleft Palate / Q000000981:diagnostic imaging* / Q000473:pathology; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005146:Facial Asymmetry / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology