title: In vivo measurement of the 3D kinematics of the temporomandibular joint using miniaturized electromagnetic trackers: technical report.
abstract: OBJECTIVE
  The aim of this study was to evaluate the use of miniaturized electromagnetic trackers (1 × 0.5 × 0.5 cm) fixed on teeth of the maxilla and mandible to analyse in vivo the 3D kinematics of the temporomandibular joint (TMJ). A third sensor was fixed to the forehead, and a fourth sensor was used as a stylus pointer to detect several anatomical landmarks in order to embed a local frame on the cranium. Temporomandibular opening/closing, chewing, laterotrusion and protrusion were examined.
  
  
  RESULTS
  The prime objective within this study was to rigidly attach electromagnetic minisensors on teeth. The key for a successful affixation was the kevlar interface. The distances between the two mandibular affixed sensors and between the two maxillar affixed sensors were overall smaller than 0.033 cm for position and 0.2° for attitude throughout the temporomandibular motions. The relative motions between a forehead sensor and the maxilla affixed sensor are too big to suggest a forehead sensor as an alternative for a maxilla affixed sensor.
  
  
  CONCLUSIONS
  The technique using miniaturized electromagnetic trackers furthers on the methods using electromagnetic trackers on external appliances. The method allows full range of motion of the TMJ and does not disturb normal TMJ function.
authors.affiliation: University College Physiotherapy Thim Van Der Laan, Landquart, Switzerland.
authors.forename: J-P
authors.initials: JP
authors.lastname: Baeyens
authors.forename: H
authors.initials: H
authors.lastname: Gilomen
authors.forename: B
authors.initials: B
authors.lastname: Erdmann
authors.forename: R
authors.initials: R
authors.lastname: Clijsen
authors.forename: J
authors.initials: J
authors.lastname: Cabri
authors.forename: D
authors.initials: D
authors.lastname: Vissers
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D003952:Diagnostic Imaging / Q000295:instrumentation* / Q000379:methods; D055590:Electromagnetic Phenomena; D005260:Female; D057918:Fiducial Markers; D005546:Forehead / Q000033:anatomy & histology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007568:Jaw / Q000033:anatomy & histology; D008297:Male; D008409:Mastication / Q000502:physiology; D008422:Materials Testing; D013704:Temporomandibular Joint / Q000502:physiology*