European Journal of Prosthodontics and Restorative Dentistry

Variability Of Centric Relation Position In TMD Patients

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Cover Date

March 2006

Print ISSN

0965-7452

Vol

14

Issue

1

Abstract

Abstract - Reproducibility of the centric relation position for patients with temporomandibular disorders (TMD) is not documented in the current literature. It was the objective of this study to assess clinical variability of the centric relation position for TMD patients with a muscle-determined technique by means of an anterior deprogramming device, the leaf gauge. A sample of 60 patients with signs of TMD was selected, 8 men (Mean age 28,6, SD 5,2) and 52 women (Mean age 30,5, SD 10,1). All patients were examined with the Research Diagnostic Criteria, including pain on movement and/or function, mouth opening, joint sounds and palpation of masticatory muscles. All 60 patients were allocated to one of the following diagnostic subgroups: myofascial pain, disk displacement with reduction, disk displacement without reduction, osteoarthritis, trauma. Twelve control subjects were taken from a previous study. Three sequential centric relation records were taken; the first one was used to mount a set of casts to an articulator. Criteria of precision were formulated beforehand: 2 out of 3 centric relation records had to be identical in a split-cast procedure. Variables XL and XR represented mandibular displacement in the sagittal plane, variables YL and YR in the transversal plane, and ZL and ZR in the vertical plane, on the left and right condylar level respectively. Variables XMIN, YMIN and ZMIN represented the minimal sagittal, transversal and vertical displacement left or right respectively. Likewise, variables XMAX, YMAX and ZMAX represented the maximal sagittal, transversal and vertical displacement left or right. XDIFF, YDIFF and ZDIFF represented the difference between the minimal and maximal values of X, Y and Z. The diagnostic subgroup trauma was excluded, because there was only one patient. The null-hypothesis of no between-group differences in within-subject and total variability was tested with an analysis of variance (ANOVA). The level of significance was set at 0.05. To minimize type I errors caused by multiple testing Scheffe’s test was used to maintain an overall significance of 0.05. No significant difference between patients and control subjects could be found for variables XL, XR, YL, YR, ZR and ZL. Variables XMIN, YMIN, ZMIN, XMAX, YMAX, ZMAX, XDIFF, YDIFF and ZDIFF showed no significant differences. Scheffe’s testing for the variables XL, XR, YL, YR, ZL and ZR, as well as the variables XMIN, YMIN, ZMIN, XMAX, YMAX, ZMAX, XDIFF, YDIFF and ZDIFF showed no significant differences. The results of this study suggest no variability in centric relation position between TMD-patients and control subjects by means of the leaf gauge.

KEY WORDS: Centric Relation, TMD, Lea/gauge