title: [Mouthguard effect of tooth distortion during clenching].
abstract: OBJECTIVE
  A mouthguard can protect stomatognathic systems from traumatic damage. However, severe occlusal wear of teeth and loss of teeth have often been found in players clinically. These problems might originate in strong clenching during sports. Although it is thought that a mouthguard may be effective for these types of clenching, the relation between mouthguards and clenching has not been sufficiently examined. In this study, the effect of a mouthguard (Drufosoft 3mm, EVA) on tooth distortion caused by clenching was measured and examined at three different clenching strengths.
  
  
  METHODS
  As a test tooth, a lower first molar was selected. A strain gauge applied to the outer surface of the buccal cusp was used to measure the distortion. A muscle balance monitor (GC) was used to regulate clenching strengths (10, 50, and 100%). The maximum-effort clenching without a mouthguard was assumed to be the 100% clenching strength. Measurements were conducted with or without mouthguard. A maximum value during clenching was assumed to be date of distortion by using analytical software AcquKnowledge (BIOPAC System Inc.). Statistical analysis software SPSS (SPSS Japan Inc.) was used for the Mann-Whitney test.
  
  
  RESULTS
  1. The tooth distortion by clenching, regardless of the presence of the mouthguard, increased as clenching power strengthened, from 10, 50 to 100%. 2. The tooth distortion, regardless of strength of clenching, was decreased by wearing the mouthguard in all subjects. At 50 and 100% clenching, it was decreased significantly by the mouthguard in all subjects.
  
  
  CONCLUSIONS
  Mouthguards decreaseed the tooth distortion caused by clenching. Therefore, a mouthguard may prevent not only traumatic injuries in contact sports but also damage to teeth and periodontal tissues and so on, which occur due to frequent strong clenching in many sports.
authors.affiliation: Department of Sports Dentistry, Tokyo Dental College. ttakeda@tdc.ac.jp
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Takeda
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Kurokawa
authors.forename: Kaoru
authors.initials: K
authors.lastname: Naito
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nara
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ninagawa
authors.forename: Shiro
authors.initials: S
authors.lastname: Miyajima
authors.forename: Masahito
authors.initials: M
authors.lastname: Shoumura
authors.forename: Jun
authors.initials: J
authors.lastname: Handa
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kawamura
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kojima
authors.forename: Mami
authors.initials: M
authors.lastname: Shibusawa
authors.forename: Toru
authors.initials: T
authors.lastname: Ogawa
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nakajima
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shimada
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishigami
mesh_terms: D000328:Adult; D001732:Bite Force; D005260:Female; D006801:Humans; D008297:Male; D008963:Molar / Q000502:physiology; D009064:Mouth Protectors; D014070:Tooth / Q000502:physiology*