Journal of Craniomandibular Function, 01/2014

This article deals with the question of the mandibular condylar position of symptom-free adults in maximum intercuspation. To this purpose, and as sequel to a study by Stamm et al (J Orofac Orthop 2004;65:280-289), scientific literature published between January 2002 and December 2012 on this topic was collated and analyzed. The inclusion criterion for study articles was a distinction between the condylar positions in maximum intercuspation depicted by imaging techniques as anterior, (con)centric and posterior. Six papers - including four study reports and two overview articles - were chosen as relevant. These confirm the observed variability of the condylar position, whereby, as shown by Stamm et al, (con)centric positions were mostly predominant. Furthermore, they show the dependence of the tomographically depicted condylar position on the layer depth of the chosen imaging technique. Keywords: imaging techniques, temporomandibular joint, occlusion, mandibular condyle

Twenty-one patients with complete dentures had 6 maxillary and 15 mandibular complete dentures relined using an open-mouth procedure. The centric relation was determined in each subject using the central bearing-point method (three times each before and after relining) in a special measuring articulator, calculating the resulting discrepancies in the condylar region after averaging. Relining the maxillary dentures resulted in a three-dimensional displacement of the condyles of on average 2.5 mm on both sides (median: 2.5 mm on the right side and 2.4 mm on the left side). Relining the mandibular dentures resulted in a three-dimensional displacement of the condyles of on average 2.0 mm on both sides (median 1.6 mm). The reproducibility of the central bearing point registration was 0.5 mm before relining and 0.3 mm after relining. This clinical-experimental study shows that on relining complete dentures, identifiable, and therefore clinically significant, discrepancies in occlusion may occur. It is therefore particularly important to check the occlusion after re-inserting relined complete dentures, which will then usually require adjustment or secondary remounting. Keywords: Occlusion, relining, open-mouth relining, closed-mouth relining, secondary remounting, complete dentures, central bearing point method, gothic arch tracing

The usefulness of jaw-tracking devices (axiography) in diagnosis of temporomandibular disorders (TMDs) remains unclear, because there are no generally accepted guidelines for the interpretation of such recordings. The objective of this study was to evaluate the diagnostic benefit of a computerized jaw tracking system for the evaluation of TMJ-related TMD. A total of 307 subjects (167 females and 140 males, mean age 35.9 ± 7.6) were selected from the cross-sectional epidemiological population-based study "Study of Health in Pomerania" (SHIP) for this evaluation. Data were collected with magnetic resonance imaging (MRI), 3D computerized axiography and clinical functional analysis. MRI examination resulted in the diagnosis no disc displacement (NDD) for 464 joints, partial disc displacement (PDD) for 107 joints, complete disc displacement with reduction (DDWR) for 5 joints and complete disc displacement without reduction (DDWOR) for 36 joints. Using MRI as the gold standard, electronic jaw tracking could separate disc displacements from sound joints with a sensitivity of 79% for right joints and 74% for left joints. Specificity of the axiography was 85% and 86% for the right and left side respectively. There was no significant correlation between clinical symptoms as pain upon palpation of the TMJ or self-reported pain of the TMJs and axiographic or MRI diagnosis. According disc displacements in the TMJ, electronic jaw tracking could achieve acceptable sensitivity and specifity levels when compared with MRI. For the diagnosis of painful TMD symptoms, however, axiography as well as MRI are of low value. Clinical examination methods should be employed. Keywords: temporomandibular disorders, temporomandibular joint dysfunction, internal derangement, computerized jaw tracking, magnetic resonance imaging, sensitivity, specificity

A modification of the occlusal situation is complex, as it is interdisciplinary as well as protracted, and it demands the patient to be very compliant. The prosthetical realization of a constructed bite position in the so-called centric position of the lower jaw has to be seen as the last invasive module in a series of therapeutic measures, which ultimately holds, and in the long term strengthens, the patient's functionally stable body static also during the day. Keywords: CMD interdisciplinary, posterior disk displacement, 3D jaw measurement, prosthetic bite position modification, MRT diagnosis