title: Occlusal accommodation and mouthguards for prevention of orofacial trauma.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of two types of occlusal accommodation on the arch separation in centric and eccentric arch positions and to assess the opposing tooth contacts in professionally made, thermoformed sports mouthguards.
  
  
  METHODS
  Maxillary and mandibular alginate impressions, a wax interocclusal record of centric occlusion together with maxillary/condylar face-bow registrations, were recorded clinically for 10 undergraduate dental students who are sports activist volunteers of the School of Medicine and Dentistry, Queen's University Belfast. Two ethylene vinyl acetate thermoformed maxillary mouthguards were made for each player (N = 20) using a standardised procedure. Ten mouthguards served both as the control (i.e. the non-accommodated) group and also the accommodated, occlusally 'imprinted' group. The other 10 mouthguards served as the accommodated, occlusally 'ground' group. Casts were articulated, each non-accommodated and accommodated mouthguard was seated and the extent of the interocclusal opening was recorded in all three arch relationships. The number of mouthguard and mandibular tooth contacts were also recorded in each position.
  
  
  RESULTS
  The increased vertical occlusal dimension that was found in the presence of non-accommodated mouthguards equated to the full-sheet thickness of the material that was used to form the mouthguards. Only mouthguards accommodated by grinding retained high levels of occlusal contact in all arch relationships that were tested.
  
  
  CONCLUSIONS
  Within the limitations of this study, the modification of the occlusal surface made by flat grinding reduced the arch separation in eccentric movements and increased the opposing tooth contacts in custom-made mouthguards. This may contribute to increased comfort, compliance and the protective effect of these appliances thus resulting in a reduction of injuries to the teeth, arches and soft tissues.
authors.affiliation: Paediatric and Preventive Dentistry, School of Medicine and Dentistry, Queen's University Belfast, BT12 6BA, UK. l.geary@qub.ac.uk
authors.forename: Julian Lindsay
authors.initials: JL
authors.lastname: Geary
authors.forename: Thomas Joseph
authors.initials: TJ
authors.lastname: Clifford
authors.forename: Martin James
authors.initials: MJ
authors.lastname: Kinirons
mesh_terms: D001265:Athletic Injuries / Q000517:prevention & control; D003724:Dental Arch / Q000033:anatomy & histology; D003725:Dental Articulators; D003766:Dental Occlusion; D003768:Dental Occlusion, Centric; D004867:Equipment Design; D005151:Facial Injuries / Q000517:prevention & control*; D006801:Humans; D007574:Jaw Relation Record; D008334:Mandible / Q000033:anatomy & histology; D008335:Mandibular Condyle / Q000033:anatomy & histology; D008437:Maxilla / Q000033:anatomy & histology; D003765:Models, Dental; D009055:Mouth / Q000293:injuries*; D009064:Mouth Protectors; D011145:Polyvinyls / Q000737:chemistry; D013499:Surface Properties; D014716:Vertical Dimension
chemical_list: D011145:Polyvinyls; C016438:ethylenevinylacetate copolymer