The influence of different registration techniques on condyle displacement and electromyographic activity in stomatognathically healthy subjects: a prospective study.
BACKGROUND
It is unclear whether different intermaxillary registration techniques are related to a physiological condylar position that permits neuromuscular equilibrium.


OBJECTIVE
This study analyzes and quantifies the effects of different registration techniques on the condyle position and how the registration technique modulates bilateral masseter and anterior temporalis muscle electromyographic activity.


METHODS
Three-dimensional electronic condylar position analysis (EPA) with an ultrasound-based jaw-tracking system and surface electromyographic activity (sEMG) was recorded during the registration of a manually guided centric relation (CR), maximal intercuspation (MI), and Gothic arch tracing guided centric relation (DIR method). Participants were 26 stomatognathically healthy volunteers (mean age, 30.6 ±9.5 years). Data were analyzed by 1-way ANOVA and post hoc Bonferroni correction (α=.05).


RESULTS
EPA showed significant differences (P<.001) for CR, MI, and DIR in the vertical, sagittal, and horizontal axes. The condyle position during DIR was found to be significantly more anteriorly and inferiorly located than with CR (P<.001) and MI (P<.04). There were no significant differences in the mean muscle activity among CR, MI, and DIR. Muscular symmetry ranged from 63.87 to 81.47%. Significantly higher symmetry for the anterior temporalis (P=.03) and the masseter (P=.03) was found during the DIR than with CR. Torque coefficients (potential laterodeviating effect) were between 88.02% (CR) and 89.94% (MI).


CONCLUSIONS
Registration technique significantly influenced the condyle position, while mean muscular activity was minimally affected. With respect to muscular balance and activation, the DIR position proved to be capable of inducing the greatest motor unit activity when compared with manually guided CR and MI.
Department of Prosthodontics, Preclinical Education and Dental Materials Science, Rheinische Friedrich-Wilhelms University of Bonn, Bonn, Germany. sabinelinsen@web.de
Sabine S
SS
Linsen
Helmut
H
Stark
Azadeh
A
Samai
D000328:Adult; D001732:Bite Force; D016302:Centric Relation; D003201:Computers; D003768:Dental Occlusion, Centric; D004576:Electromyography; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007574:Jaw Relation Record / Q000379:methods*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology; D008335:Mandibular Condyle / Q000033:anatomy & histology* / Q000502:physiology; D008406:Masseter Muscle / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology; D009469:Neuromuscular Junction / Q000502:physiology; D011446:Prospective Studies; D012984:Software; D013703:Temporal Muscle / Q000502:physiology*; D019415:Torque; D014465:Ultrasonics / Q000295:instrumentation