title: Formation of vacuum-formed and pressure-formed mouthguards.
abstract: OBJECTIVE
  The method used to form mouthguards should be carefully selected in order to obtain their full preventive benefits. The aim of this study was to examine the differences of mouthguard characteristics according to the forming methods.
  
  
  METHODS
  Mouthguard sheets of 3.8-mm ethylene vinyl acetate were vacuum-formed and pressure-formed on a working model. The sheets were formed when heating causing them to displace 15 mm from baseline. Mouthguard thickness was measured at the labial surface of the central incisor, the buccal surface of the first molar, and the occlusal surface of the first molar. The fit of the mouthguard was measured at the central incisor and the first molar. Differences in the thickness and fit between the vacuum-formed and pressure-formed mouthguards were analyzed by two-way analysis of variance and the Bonferroni method.
  
  
  RESULTS
  Mouthguard thickness varied between the central incisors and first molars (P<.01). The thicknesses at the labial surface of the central incisor and the buccal surface of the first molar were greater in the vacuum-formed mouthguards than in the pressure-formed mouthguards (P<.01). The fit was better in the pressure-formed mouthguards than that in the vacuum-formed mouthguards (P<.01).
  
  
  CONCLUSIONS
  The vacuum-forming method maintained the mouthguard thickness, while the pressure-forming method obtained better fit.
authors.affiliation: Department of Removable Prosthodontics, The Nippon Dental University School of Life Dentistry at Niigata, Niigata, Japan.
authors.forename: Fumi
authors.identifier: http://orcid.org/0000-0002-0699-0637
authors.initials: F
authors.lastname: Mizuhashi
authors.affiliation: Department of Removable Prosthodontics, The Nippon Dental University School of Life Dentistry at Niigata, Niigata, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Koide
mesh_terms: D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D009064:Mouth Protectors; D011312:Pressure; D019876:Sports Equipment; D014618:Vacuum; D014753:Vinyl Compounds / Q000737:chemistry
chemical_list: D014753:Vinyl Compounds; C011566:vinyl acetate
keywords: mouthguard; pressure-forming; vacuum-forming