title: Finite element analysis of the cranial base in subjects with Class III malocclusion.
abstract: The association between cranial base morphology and Class III malocclusion is poorly understood. This study analyses local shape- and size differences in cranial base configurations of Class I and Class III subjects, employing finite element (FEM) analysis. Seventy-three prepubertal European-American children with Class III malocclusion were compared to their counterparts with a normal, Class I molar occlusion. Lateral cephalographs were traced, checked and subdivided into age- and sex-matched groups. Thirteen points on the cranial base were identified and digitized, providing a geometrical cranial base representation. Average cranial geometries were scaled to an equivalent size and a FEM analysis, capable of depicting and quantifying local shape- and size-change, employed to highlight regionalized, morphological differences. While the anterior cranial base was more homogeneous for shape-change, significant, localized anisotropy in the posterior regions of the cranial base and around sella turcica was evident. For size-change, areas of negative allometry were located posteriorly, but dilations in the mid- and anterior cranial base also were apparent. It is concluded that morphological alterations within the petro-occipital complex accompanied by changes in the sphenoidal and ethmoidal regions induce deviation from a normal cranial base configuration to one associated with deficient orthocephalization and an appearance of Class III malocclusion.
authors.affiliation: Department of Dental Surgery & Periodontology, Dundee Dental Hospital & School, University of Dundee, UK.
authors.forename: G D
authors.initials: GD
authors.lastname: Singh
authors.forename: J A
authors.initials: JA
authors.lastname: McNamara
authors.forename: S
authors.initials: S
authors.lastname: Lozanoff
mesh_terms: D000367:Age Factors; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003196:Computer Graphics; D003799:Dental Stress Analysis / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000473:pathology*; D019291:Skull Base / Q000473:pathology*