Andree Piwowarczyk

An Evaluation of Horizontal Jaw Relations During Standing and Sitting with Open or Closed Eyes

Abstract When determining the horizontal jaw relation and mandibular movements, a question arises as to the appropriate choice of registration positions. The current study was carried out using 22 adults with full dentition who did not have any discomfort in their skeletal and craniomandibular systems. Occlusion and mandibular movements were investigated with open and closed eyes in standing and sitting positions using an electronic, central-bearing tracing device. The coordinates of the measured parameters are presented using a two-dimensional computer vector diagram. The non-parametric Friedman test was used for statistical data analysis. The measured data obtained for the initial habitual centric relation record (HR), centric relation record (CR), final habitual centric relation record (HR), and protrusion (P) did not significantly differ in the sitting and standing positions or with opened and closed eyes (p=1.00). With closed eyes, the differences in the average values between the two condylar positions (initial HR/final HR, initial HR/CR, and final HR/CR) decreased in a manner that was independent of the registration position. The CR that was measured in a sitting position with closed eyes was 2.26 mm more retrusive than that measured with open eyes. Before and after CR measurements, only laterotrusion showed significant differences (p=0.02) in patients who were standing with closed eyes. It was concluded that the registration position and visual system could individually influence the measurements of condylar position and mandibular movements. From a clinical perspective, these measurements exhibited the smallest differences when they were conducted with patients in a sitting position with closed eyes.

Retrospective Study on the Evaluation of the TMJ by MRI Using a Newly Developed Standardized Evaluation Form

Abstract The objectives of this retrospective study were to systematically assess the temporomandibular joint (TMJ) using a newly developed standardized evaluation form with 16 parameters based on MRI diagnostics and to verify the reliability of the MRI diagnoses. One hundred fifty-four (154) TMJs of 77 patients with arthrogenic complaints were evaluated using MRI on two planes (parasagittal, paracoronal), in both closed-mouth and open-mouth positions. The sequences used were intermediary FLASH and spin echo sequences using T1 or T2 weighting with fat suppression. Examination of the reliability of the MRI evaluations of three independent observers evaluating 60 randomly selected TMJ from among the overall sample using the new evaluation form yielded an average Pearson contingency coefficient of between 0.64 and 0.70 with regard to the 16 parameters studied. In the evaluation of the 77 left (L) and 77 right (R) joints, the biplanar morphology of the disk was the most frequent with 24.7% (L) and 32.5% (R). In paracoronal projection, medial displacement of the disk was seen in 7.9 % (L, R) of the cases and lateral displacement in 6.4% (L) and 3.2% (R). The use of the new evaluation form, in combination with MRI of the TMJ, demonstrated a substantial reliability of the diagnoses. In TMD patients, the biconcave disk shape cannot be considered the sole normal, standard situation. The presence of lateral and medial disk displacement should be given more diagnostic consideration.