title: [Studies evaluating measurement accuracy of CMS-JAW, a jaw motion tracking device with six degrees of freedom using an ultrasonic recording system].
abstract: OBJECTIVE
  For diagnoses of temporomandibular dysfunction, reports indicate the importance of analyzing jaw movements using a jaw motion tracking device with six degrees of freedom. However, such devices are not widely applied in clinical practice, due to difficulty of use. To determine whether CMS-JAW (a newly developed six degrees of freedom jaw motion tracking device that features easy analysis of jaw movements) offers the measurement accuracy required for clinical use, we evaluated the device by measuring condyle translation and rotation during jaw movement.
  
  
  METHODS
  In this study, we evaluated measurement accuracy by comparing measurements of condyle movements obtained from the Win Jaw System, a comparable jaw motion tracking device with six degrees of freedom based on an ultrasonic recording system; the Gnathohexagraph II, a device based on a different measurement principle; and the CMS-JAW. In the experiment, we confirmed the condyle translations and rotations obtained by each device by measuring distances and angles, respectively, with a micro slider for three-dimensional measurements (to an accuracy of 0.01 mm and 0.02 mm) and a digital protractor (to an accuracy of 0.1 degrees).
  
  
  RESULTS
  No significant distortions were observed in the space replicated based on the range of condyle translations obtained with CMS-JAW. Deviations from theoretical values were greatest along the z-axis, with a maximum error of 0.20 mm and root mean square (RMS) error of 0.10 mm. The maximum error for angles of condyle rotation was 0.50 degrees; RMS errors ranged from 0.05 to 0.30 degrees.
  
  
  CONCLUSIONS
  Our analysis of condyle movement demonstrates that the CMS-JAW provides acceptable measurement accuracy for clinical applications.
authors.affiliation: Department of Oral Diagnostics, Nihon University School of Dentistry at Matsudo. uchida.takashi@nihon-u.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchida
authors.forename: Jun
authors.initials: J
authors.lastname: Sakai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Watanabe
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kitagawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Aida
authors.forename: Takachika
authors.initials: T
authors.lastname: Saito
authors.forename: Takanori
authors.initials: T
authors.lastname: Ito
mesh_terms: D006801:Humans; D007568:Jaw / Q000502:physiology*; D008335:Mandibular Condyle / Q000502:physiology; D009068:Movement / Q000502:physiology*; D011476:Prosthodontics / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000295:instrumentation*