title: Biomechanical effects of rapid palatal expansion on the craniofacial skeleton with cleft palate: a three-dimensional finite element analysis.
abstract: OBJECTIVE
  To explore the biomechanical effects of rapid palatal expansion (RPE) on the craniofacial skeleton with cleft palate.
  
  
  METHODS
  A finite element model of a patient's skull with cleft lip and palate (CLP) was generated using data from spiral computed tomographic (CT) scans. Finite elemental analysis (FEA) was performed to depict the physiological changes and stress distribution in craniofacial structures loaded with orthopedic forces that created 5 mm of displacement on the region of the maxillary first premolar and first molar crown.
  
  
  METHODS
  A 14-year-old girl with left complete unilateral CLP was included in this study.
  
  
  METHODS
  Spiral CT was carried out prior to any treatment.
  
  
  METHODS
  Three-dimensional (3D) features of displacement and stress distribution were analyzed following application of transverse orthopedic force.
  
  
  RESULTS
  Marked amount of displacement and deformation occurred in the dental region. Asymmetric displacement and deformation of UCLP under RPE were evident. The stress generated by RPE was dispersed around the cleft palate and nasal cavity, and was distributed at the buttress of the maxilla-inferior border of the nasal cavity, outboard of the orbit, and central frontal bone near the nasion.
  
  
  CONCLUSIONS
  Application of RPE to UCLP patients induces a pyramid-like displacement of the nasomaxillary complex along with fan-like expansion of the upper dental arch. The uniqueness of RPE with UCLP, however, lies in the asymmetric expansion and dispersed stress distribution around the lateral maxilla buttress and outboard of orbit.
authors.affiliation: Department of Orthodontics, School of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai Research Institute of Stomatology, Shanghai, China.
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Pan
authors.forename: Yufen
authors.initials: Y
authors.lastname: Qian
authors.forename: Jia
authors.initials: J
authors.lastname: Yu
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wang
authors.forename: Yousheng
authors.initials: Y
authors.lastname: Tang
authors.forename: Gang
authors.initials: G
authors.lastname: Shen
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000503:physiopathology; D001696:Biomechanical Phenomena; D002971:Cleft Lip / Q000503:physiopathology; D002972:Cleft Palate / Q000503:physiopathology*; D003198:Computer Simulation; D003724:Dental Arch / Q000503:physiopathology; D005147:Facial Bones / Q000503:physiopathology*; D005260:Female; D020342:Finite Element Analysis; D005624:Frontal Bone / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008437:Maxilla / Q000503:physiopathology; D008954:Models, Biological; D008963:Molar / Q000503:physiopathology; D009295:Nasal Bone / Q000503:physiopathology; D009296:Nasal Cavity / Q000503:physiopathology; D009915:Orbit / Q000503:physiopathology; D010155:Palatal Expansion Technique; D012886:Skull / Q000503:physiopathology*; D013314:Stress, Mechanical; D036542:Tomography, Spiral Computed