title: Stresses in the midpalatal suture in the maxillary protraction therapy: a 3D finite element analysis.
abstract: BACKGROUND
  The aim of the present work was to evaluate the stress magnitudes and directions along the midpalatal suture in the maxillary protraction therapy.
  
  
  METHODS
  The geometry of the maxilla and teeth were digitally reconstructed based on computer tomography images obtained from the skull of a girl in a mixed dentition stage with skeletal and dental class III malocclusion. An appliance commonly used for rapid palatal expansion (RPE) was also digitally modeled for anchorage of the protraction force and meshed for finite element analysis. The maxillary protraction was simulated applying 600 cN (300 cN for each side) directed 30° forward and downward to the maxillary occlusal plane.
  
  
  RESULTS
  The principal stresses, through the force application, exhibited similar distribution patterns. A higher stress area was observed in the region of the midpalatal suture located in front of the incisive canal. All the sections showed vectors of compressive nature.
  
  
  CONCLUSIONS
  Because of the compressive nature of the stresses distributed along the midpalatal suture in the maxillary protraction therapy simulation, which is opposite to the natural growth transversal tendency, maxillary expansion is advisable in clinical cases.
authors.affiliation: School of Health and Biosciences, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil. tanakaom@gmail.com.|The Center for Advanced Dental Education, Saint Louis University, St. Louis, MO, USA. tanakaom@gmail.com.
authors.forename: Orlando M
authors.initials: OM
authors.lastname: Tanaka
authors.affiliation: School of Health and Biosciences, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil.
authors.forename: Amando Yukio
authors.initials: AY
authors.lastname: Saga
authors.affiliation: Southwest Bahia State University-UESB, Jequié, Bahia, Brazil.
authors.forename: Matheus Melo
authors.initials: MM
authors.lastname: Pithon
authors.affiliation: Federal University of Paraná-UFPR, Paraná, Brazil.
authors.forename: Marco Andre
authors.initials: MA
authors.lastname: Argenta
mesh_terms: D001696:Biomechanical Phenomena; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008437:Maxilla; D010155:Palatal Expansion Technique; D013537:Sutures