Objectives: The aim of this study was to examine different central bearing point methods in patients with and without temporomandibular disorders (TMD) by an experienced and unexperienced examiner.
Material and methods: The 20 fully dentulous subjects were screened for TMD based on the Research Diagnostic Criteria for TMD and distinguished into functional impaired and functional healthy groups. The mandibular relationship was recorded by an electronic central bearing tracing device (IPR-System, IPR GmbH, Oldenburg, Germany) with an integrated pressure sensor. Three bite registration methods were performed using this device: initial neuromuscular position, final neuromuscular position after dynamic sequences with the intraoral pin (=neuromuscular deprogramming), and centric relation guided manually by an experienced and an unexperienced examiner.
Results: The neuromuscular positions before and after neuromuscular deprogramming were not significantly different (paired t test as a group comparison test: transverse: p = 0.369; sagittal: p = 0.486). Both positions were significantly anterior in comparison to the manually guided centric relation (paired t test as a group comparison test: p < 0.0001). The neuromuscular positions before and after deprogramming tend to have high scattering values.
Conclusion: By means of the central bearing point method, the manually guided centric relation is the one which is sufficiently reproducible. It seems doubtful to take the significant anterior neuromuscular position for a definite reconstruction.
Clinical relevance: Using the central bearing point method, the manually guided centric relation should be preferred, whereas the neuromuscular position should not be used for definite reconstructions.
Keywords: Centric bearing device; Centric relation; Maxillomandibular relationship; TMD.