Neuromuscular Position of the TMJ Condyle in Fully Dentate Volunteers Characteristics and Potential Indications.

Abstract

Purpose: This study comprises the fifth and final part of a comprehensive investigation of the positions of the temporomandibular joint condyles. In this evaluation, we wanted to investigate the neuromuscular position of the mandible.

Materials and methods: The neuromuscular condylar positions were recorded by four independent operators in 81 fully dentate subjects with healthy oral function using a central bearing point system and rapid closing movements. The "most frequent adduction point" was determined, and the recordings were repeated twice for each subject. The subjects' maxillary casts were mounted in an articulator using an individual facebow transfer, subsequently the mandibular. casts were mounted with a central-bearing-point registration on the tip of the Gothic arch, i.e. in centric condylar position. A custom-made electronic measuring articulator was used to determine the spatial distance between the condyles in centric relation, maximal occlusion and the newly determined neuromuscular position.

Results: The reproducibility of the neuromuscular registrations was on average 0.52±0.16 mm (range 0.04-2.53 mm) with the right and left side averaged. The spatial distances of the condyles between maximal intercuspal position and neuromuscular positions were 0.88±0.30 mm (range 0.12-5.98 mm), again averaged for the right and left sides, whereas the ones between the centric condylar position and the neuromuscular positions were 0.83±0.27 mm (range 0.10-7.89 mm).

Conclusions: The neuromuscular mandibular position is neither identical to maximal intercuspal position nor to centric relation. It can therefore be concluded, that the registration of the neuromuscular adduction field should not be recommended for prosthodontic restorations in dentate or edentulous patients.