title: An investigation into the relationship between thickness variations and manufacturing techniques of mouthguards.
abstract: BACKGROUND
  The aim of this study was to measure the finished thickness of a single identical 4-mm EVA mouthguard model from a large fabricated sample group and to evaluate the degree of material thinning and variations during the fabrication process.
  
  
  METHODS
  Twenty boxes were distributed to dental technician participants, each containing five duplicated dental models (n = 100), alongside 5 × 4 mm mouthguard blanks and a questionnaire. The mouthguards were measured using electronic callipers (resolution: ±0.01 mm) at three specific points. The five thickest and thinnest mouthguards were examined using a CT scanner to describe the surface typography unique to each mouthguard, highlighting dimensional thinning patterns during the fabrication process.
  
  
  RESULTS
  Of the three measurement points, the anterior sulcus point of the mouthguard showed a significant degree of variation (up to 34% coefficient of variation), in finished mouthguard thickness between individuals. The mean thickness of the mouthguards in the anterior region was 1.62 ± 0.38 mm with a range of 0.77-2.80 mm. This variation was also evident in the occlusion and posterior lingual regions but to a lesser extent (up to 12.2% and 9.8% variations, respectively).
  
  
  CONCLUSIONS
  This study highlights variability in the finished thickness of the mouthguards especially in the anterior sulcus region measurement point, both within and between individuals. At the anterior region measurement point of the mouthguard, the mean thickness was 1.62 mm, equating to an overall material thinning of 59.5% when using a single 4-mm EVA blank. This degree of thinning is comparative to previous single operator research studies.
authors.affiliation: Department of Exercise and Sport Science/Institute for Performance Research, Manchester Metropolitan University, Crewe, Cheshire, UK.
authors.forename: Timothy
authors.initials: T
authors.lastname: Farrington
authors.affiliation: Department of Prosthetic Facial Rehabilitation, Guys Hospital, London, UK.
authors.forename: Trevor
authors.initials: T
authors.lastname: Coward
authors.affiliation: Department of Exercise and Sport Science/Institute for Performance Research, Manchester Metropolitan University, Crewe, Cheshire, UK.
authors.forename: Gladys
authors.initials: G
authors.lastname: Onambele-Pearson
authors.affiliation: School of Healthcare Science, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Taylor
authors.affiliation: Worcestershire Royal Hospital, Worcester, Worcestershire, UK.
authors.forename: Philip
authors.initials: P
authors.lastname: Earl
authors.affiliation: Department of Exercise and Sport Science/Institute for Performance Research, Manchester Metropolitan University, Crewe, Cheshire, UK.
authors.forename: Keith
authors.initials: K
authors.lastname: Winwood
mesh_terms: D004867:Equipment Design; D006801:Humans; D008422:Materials Testing; D003765:Models, Dental; D009064:Mouth Protectors; D013499:Surface Properties; D014057:Tomography, X-Ray Computed
keywords: custom mouthguards; maxillofacial trauma; mouthguard thickness; sports dentistry; thermoforming