title: Effect of ethylene vinyl acetate (EVA) closed cell foam on transmitted forces in mouthguard material.
abstract: OBJECTIVE
  To compare transmitted forces through ethylene vinyl acetate (EVA) mouthguard material and the same EVA material with gas inclusions in the form of a closed cell foam.
  
  
  METHODS
  EVA mouthguard materials with and without foam gas inclusions and 4 mm thick were impacted with a constant force from an impact pendulum. Various porosity levels in the foam materials were produced by 1%, 5%, and 10% by weight foaming agent. The forces transmitted through the EVA after energy absorption by the test materials were measured with a force sensor and compared.
  
  
  RESULTS
  Only minor non-significant differences in transmitted forces through the EVA with and without foam were shown.
  
  
  CONCLUSIONS
  The inclusion of gas in the form of a closed cell foam in 4 mm thick EVA mouthguard materials did not improve the impact performance of the EVA mouthguard material.
authors.affiliation: University of Queensland, 500 Sandgate Road, Clayfield 4001, Queensland, Australia. airgard@mgard.com.au
authors.forename: B
authors.initials: B
authors.lastname: Westerman
authors.forename: P M
authors.initials: PM
authors.lastname: Stringfellow
authors.forename: J A
authors.initials: JA
authors.lastname: Eccleston
authors.forename: D J
authors.initials: DJ
authors.lastname: Harbrow
mesh_terms: D003799:Dental Stress Analysis / Q000379:methods; D004867:Equipment Design / Q000379:methods; D019544:Equipment Failure Analysis; D008422:Materials Testing; D009064:Mouth Protectors / Q000592:standards*; D011145:Polyvinyls; D019876:Sports Equipment / Q000592:standards*; D013314:Stress, Mechanical
chemical_list: D011145:Polyvinyls; C016438:ethylenevinylacetate copolymer