title: Cranial-base morphology in adults with skeletal Class III malocclusion.
abstract: BACKGROUND
  The objectives of this study were to clarify the characteristics of cranial-base morphology in adults with skeletal Class III malocclusion and investigate factors relating to the establishment of a skeletal Class III malocclusion.
  
  
  METHODS
  Initial lateral cephalograms of women were examined. Subjects with an ANB angle of 0° to 4°, normal overjet and overbite, and a Class I molar relationship were classified as Class I (n = 86). Those with an ANB angle less than -1°, a Wits appraisal less than 2 mm, a negative overjet, and a Class III molar relationship were the Class III group (n = 86) in this study. Angular, linear, and coordinate measurements were made. Multivariate analysis of variance and the Student t test were used to analyze significant differences between the 2 groups. Discriminant analysis, logistic regression analysis, and decision analysis were used to identify which cranial-base and maxillomandibular variables influenced the establishment of a skeletal Class III malocclusion.
  
  
  RESULTS
  The Class III group had smaller values for NSBa, SeSBa, FH-SSe, and FH-SBa. Sphenoidale and basion were more inferior and anterior than those of the Class I group. There was no difference in the anterior and posterior cranial-base lengths between the groups. Greater mandibular length was the first major characteristic in the Class III group, followed by smaller values for SeSBa and NSBa.
  
  
  CONCLUSIONS
  Cranial-base morphology in adults with a skeletal Class III malocclusion is different from that in a skeletal Class I malocclusion. Smaller cranial-base angles, steeper posterior cranial bases, more inferiorly positioned sphenoidale, and more anteriorly positioned basion are major characteristics of skeletal Class III malocclusions. These characteristics play important roles in the establishment of a skeletal Class III malocclusion.
authors: Postgraduate student, Departments of Orthodontics and Translational Research, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors: Seetala
authors: S
authors: Sanggarnjanavanich
authors: Assistant professor, Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors: Toshiko
authors: T
authors: Sekiya
authors: Associate professor, Department of Translational Research, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors: Yoshiaki
authors: Y
authors: Nomura
authors: Postgraduate student, Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors: Takahiro
authors: T
authors: Nakayama
authors: Professor and chairman, Department of Translational Research, School of Dental Medicine, Tsurumi University, Yokohama, Japan.
authors: Nobuhiro
authors: N
authors: Hanada
authors: Professor and chairman, Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama, Japan. Electronic address: nakamura-ys@tsurumi-u.ac.jp.
authors: Yoshiki
authors: Y
authors: Nakamura
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods / Q000706:statistics & numerical data; D003663:Decision Trees; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D008313:Malocclusion, Angle Class III / Q000209:etiology / Q000473:pathology*; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology; D009295:Nasal Bone / Q000473:pathology; D057887:Overbite / Q000473:pathology; D015203:Reproducibility of Results; D012658:Sella Turcica / Q000473:pathology; D019291:Skull Base / Q000473:pathology*; D013100:Sphenoid Bone / Q000473:pathology; D055815:Young Adult