title: Comparison of the replicability of routinely used centric relation registration techniques.
abstract: OBJECTIVE
  This study was conducted to determine statistically the most repeatable mandibular position of 3 centric relation methods.
  
  
  METHODS
  Three centric relation recording methods commonly reported in the literature were selected: bimanual mandibular manipulation with a jig, chin point guidance with a jig, and Gothic arch tracing. Fourteen healthy adult volunteers (7 males and 7 females), with an average age of 26.61 +/- 4.20 years and no history of extractions, temporomandibular joint dysfunction, or orthodontic treatment, were selected for the study. Accurate casts were mounted on an articulator (Denar D4A) by means of a facebow and maximum intercuspation silicone registration record. A mechanical 3-dimensional mandibular position indicator was constructed and mounted on the articulator enabling the operator to analyze the mandibular positions in 3 spatial axes (x, anteroposterior; y, superoinferior; z, mediolateral shift). Each centric relation method was recorded four times on each subject (at baseline, 1 hour, 1 day, and 1 week at approximately the same time of day). Records were transferred to the articulator, and data were extracted using a stereomicroscope modified to accept the mandibular position indicator.
  
  
  RESULTS
  Variability within subjects ranged from 0.03 mm (left-side z axis for the bimanual method) to 1.6 mm (left-side y axis for the Gothic arch method). To indicate the least variable (most repeatable) method a comparison was made using the F test. The bimanual method was the most consistent, showing between 10.11 (p = 1) and 0.438 (p = 0.005) times less variation than the Gothic arch method (the least consistent). The repeatability of the chin point guidance method was somewhere between the other 2 methods.
  
  
  CONCLUSIONS
  The results of this study showed that of the 3 centric relation methods evaluated, the bimanual manipulation method positioned the condyles in the temporomandibular joint with a more consistent repeatability than the other 2 methods, whereas the Gothic arch was the least consistent method.
authors.affiliation: Department of Adult Dental Care, School of Clinical Dentistry, University of Sheffeld, Sheffield, UK.
authors.forename: Alireza
authors.initials: A
authors.lastname: Keshvad
authors.forename: Raymond B
authors.initials: RB
authors.lastname: Winstanley
mesh_terms: D000328:Adult; D016302:Centric Relation; D002508:Cephalometry / Q000379:methods*; D002680:Chin / Q000033:anatomy & histology; D003725:Dental Articulators; D003768:Dental Occlusion, Centric; D005260:Female; D006801:Humans; D008297:Male; D003765:Models, Dental; D015203:Reproducibility of Results; D013704:Temporomandibular Joint / Q000502:physiology*; D014070:Tooth / Q000033:anatomy & histology*