Influence of alteration of occlusal relationship on activity of jaw closing muscles and mandibular movement during submaximal clenching

Abstract

The aim of this study was to investigate the relationships between occlusal contacts, responses of muscles, and jaw movements during simulated clenching. Seven healthy human males who possessed complete natural dental arches with normal occlusion, ranging from 24 to 29 years of age, volunteered for this study. Acrylic occlusal stops were fabricated for the lower jaw to simulate various occlusal conditions. Vertical movements of the lower jaw were measured by four sets of linear variable differential transformers. Simultaneously, electromyographic (EMG) activity from the bilateral masseter and anterior temporal muscles was measured. Under experimentally altered occlusal conditions, the subjects performed clenching tasks at 50% of their maximal voluntary contraction level. Analysis of EMG responses revealed clenching on the unilateral occlusal support tended to cause a unilateral activity of the ipsilateral anterior temporalis. Analysis of the movement amplitude revealed a significant difference between the experimental occlusal conditions (P < 0.05). Clenching on unilateral occlusal stops caused a larger upward movement on the contralateral side. Bilateral first premolar clenching without molar support caused a larger upward movement of the mandible in the posterior region, whereas bilateral second molar clenching did not cause a significant upward movement.

Behavior analysis of electromyographic activity of the masseter muscle in sleep bruxers

“…However, there were no significant changes in 2, 4 and 6 weeks after the insertion of either splint (Baba et al, 2000).…”

“…In another patient it could be observed an inverse situation: significant differences on EMG signs on the right masseter and no significant differences on EMG signs on the left masseter. This situation of different results found in masseter muscles of the same individual can be explained by (Baba et al, 2000), which showed that inadequate force distribution of the masticatory muscles and temporomandibular joints, can lead to occlusal asymmetry.…”

Effect of different dental articulating papers on SEMG activity during maximum clenching

“…For example, Christensen and Rassouli have reported motor facilitation on the masseter muscle on the side of a rigid unilateral interference and motor inhibition on the opposite side during forceful clenching (Christensen and Rassouli, 1995). According to Baba, an increase in the activity of anterior temporalis ipsilateral muscle will also occur, when an interference is placed (Baba et al , 2000). Using EMG, Belser and Hannam (Belser and Hannam, 1985) reported that lateral clenching efforts on the natural canine caused unilateral activity in the anterior and posterior temporal muscles with clear dominance on the working-side; the introduction of an experimental balancing interference changed these unilateral activity patterns to bilateral.…”

Kein erhöhtes Risiko für kraniomandibuläre Dysfunktionen und Bruxismus im Kindes- und Jugendalter während der kieferorthopädischen Therapie*

“…Ursachen für Bruxismus können sowohl zentral als auch peripher liegen [33]. Es gibt bislang allerdings nur widersprüchliche Angaben darüber, ob und wie die Zahnstellung (oder deren Veränderung im Zuge kieferorthopädischer Behandlungen) Einfluss auf Bruxismusaktivitäten nimmt [1,39,40].…”

“…Bruxism can have central and peripheral causes [33]. However, there has been controversy as to if and how tooth position (or its change due to orthodontic treatment) affects bruxing behavior [1,39,40].…”