title: A three-dimensional finite element analysis of the sports mouthguard.
abstract: OBJECTIVE
  The aim of this study was to evaluate the compressive and tensile stresses on dentin and enamel in five different situations: no mouthguard and mouthguards from 1 mm thickness up to 4 mm thickness, using finite element analysis.
  
  
  METHODS
  A three-dimensional geometry of an upper right central incisor was obtained from a computed tomography and transformed into a mesh separating enamel from dentin. A mouthguard was created covering the buccal surface of the enamel in different thicknesses, and a rubber ball with a velocity of 5 m s(-1) was made as the impact object.
  
  
  RESULTS
  The maximum principal stress and the minimal principal stress were evaluated in all situations on dentin and enamel. Both maximum and minimal stress on enamel had the greatest value on the control situation (no mouthguard), and their value decreased as the mouthguard thickness increased. The reduction ranged from 66.62% to 85.5% for compressive stress and from 9.76% to 33.37% for tensile stress on enamel. The results for dentin were similar among the situations with or without mouthguards.
  
  
  CONCLUSIONS
  The mouthguard had beneficial effect considering the stresses on enamel, and between the mouthguard thickness of 3 and 4 mm, there was minimum difference.
authors.affiliation: Faculdade de Odontologia da Universidade de São Paulo, São Paulo, Brazil. ivan.gialain@usp.br.
authors.forename: Ivan Onone
authors.initials: IO
authors.lastname: Gialain
authors.affiliation: Faculdade de Odontologia da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Neide Pena
authors.initials: NP
authors.lastname: Coto
authors.affiliation: Departamento de Engenharia Mecatrônica e Sistemas Mecânicos, Escola Politécnica da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Larissa
authors.initials: L
authors.lastname: Driemeier
authors.affiliation: Centro de Tecnologia da Informação Renato Archer, São Paulo, Brazil.
authors.forename: Pedro Yoshito
authors.initials: PY
authors.lastname: Noritomi
authors.affiliation: Faculdade de Odontologia da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Reinaldo Brito E
authors.initials: RB
authors.lastname: Dias
mesh_terms: D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D009064:Mouth Protectors; D013177:Sports; D019876:Sports Equipment; D013314:Stress, Mechanical
keywords: finite element analysis; mouthguard; shock absorption; sports dentistry