title: Observations of interproximal contact relations during clenching.
abstract: OBJECTIVE
  Previous studies have shown that molar teeth pulsate at rest and displace linguoapically during clenching at maximal intercuspation. The aim of this study was to investigate interproximal contact during clenching by means of a charge coupled device (CCD) microscope.
  
  
  METHODS
  Two male subjects aged 28 years with normal dentition and occlusions were selected for in vivo research. Optimum contact tightness was observed at contact points that were defined by some resistance to the insertion of a 50-micron-thick stainless steel strip; however, a 110-micron strip could not be inserted there [corrected]. Spaces between the teeth were detected using a CCD microscope on the buccal side by light bands emitted from the lingual side. During static observation, the chosen distance between the microscope and light guide was maintained using a special device. For dynamic observation, a palatal and lingual plate with a light source was fitted to each subject. Subjects were directed to clench with habitual occlusal force. To compare with in vivo observations, the relation between the width of the light band and the interproximal distance was estimated in vitro using 2 extracted teeth. Light bands were analyzed using software.
  
  
  RESULTS
  In the 2 subjects studied, there was a 3- to 21-micron distance between adjacent teeth at rest, which disappeared during clenching.
  
  
  CONCLUSIONS
  The results of the study sample examined indicate that teeth do not make contact with adjacent teeth at rest, but do so during clenching.
authors.affiliation: Department of Fixed Prosthodontics, Faculty of Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan. k.kasahara.pro2@dent.tmd.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Kasahara
authors.forename: H
authors.initials: H
authors.lastname: Miura
authors.forename: M
authors.initials: M
authors.lastname: Kuriyama
authors.forename: H
authors.initials: H
authors.lastname: Kato
authors.forename: S
authors.initials: S
authors.lastname: Hasegawa
mesh_terms: D000328:Adult; D001732:Bite Force; D003766:Dental Occlusion; D003799:Dental Stress Analysis; D006801:Humans; D007574:Jaw Relation Record / Q000379:methods; D008027:Light; D008297:Male; D009119:Muscle Contraction; D009811:Odontometry / Q000379:methods; D014070:Tooth / Q000033:anatomy & histology / Q000502:physiology*; D014086:Tooth Mobility