Masticatory muscle activities during rhythmic jaw movement associated with tooth contact in lightly anesthetized rats

1984 ◽  
Vol 85 (1) ◽  
pp. 169-177 ◽  
Author(s):  
Yoshiaki Yamada ◽  
Kyuhachiro Shimada
Author(s):  
Mohammed Saifuddin ◽  
Shahana Begum ◽  
Hiroshi M Ueda ◽  
Keisuke Miyamoto ◽  
Kazuo Tanne

Introduction: It is considered now-a-days that patients with transverse craniofacial deformity might have differences in masticatory muscle activity between both sides; and as masticatory muscle activity takes place throughout the usual daily life; therefore, it might have some relation with the transverse craniofacial morphology. The present study was carried out to find out any association between balance of masticatory  muscle activity during usual daily life and transverse craniofacial morphology or tooth contact area in patients with transverse jaw deformity.Subjects and Methods: All the controls and patients for the study were selected from our staffs and patients coming to Orthodontic Clinic, Hiroshima University Dental Hospital, respectively. Thirteen males and two females (mean and s.d. of ages: 28.6 ± 1.9 years) served as the controls. They had Angle’s Class I molar relationship, no severe malocclusion, no complaints of temporomandibular disorder (TMD).The patient group was consisted of 10 males and five females (mean and s.d. of ages: 19.9 ± 5.3 years) with lateral shift of the mandible. They had malocclusion such as cross-bite and severe crowding, but no complaints of TMD. Portable digital EMG recording device were used to record the EMG from the bilateral masster and anterior temporal muscles. The diurnal recording was carried out for consecutive 142 minutes and divided into two periods of usual daytime and mealtime for analysis. After the diurnal recording, the subjects were allowed to go back home with the electrodes in position and then nocturnal EMG recording was performed again at night with the usual sleeping posture for 142 minutes. Posteroanterior cephalometric analysis and tooth contact area were measured for all the subjects.Result: No significant correlations were found for both the muscles neither with transverse craniofacial morphology nor with the tooth contact area for all the three periods of usual daily life, although a significant correlation was detected between the A-B distance and AI of the anterior temporal muscle during usual daytime.Conclusion: It is suggested that masticatory muscle activity during usual daily life in patients with transverse craniofacial deformity may not be related only to such factors as skeletal deformity or tooth contact area but governed by other important factors like occlusal interference, premature contacts, instability and so on.Ban J Orthod & Dentofac Orthop, October 2012; Vol-3, No.1


Cephalalgia ◽  
2007 ◽  
Vol 27 (6) ◽  
pp. 542-549 ◽  
Author(s):  
AG Glaros ◽  
D Urban ◽  
J Locke

To assess the diagnostic and behavioural overlap of headache patients with temporomandibular disorders (TMD), individuals recruited from the general population with self-described headaches were compared with non-headache controls. The examination and diagnostic procedures in the Research Diagnostic Criteria (RDC) for TMD were applied to both sets of subjects by a blinded examiner. Following their examination, subjects used experience sampling methods to obtain data on pain, tooth contact, masticatory muscle tension, emotional states and stress. Results showed that a significantly higher proportion of the headache patients received an RDC/TMD diagnosis of myofascial pain than non-headache controls. Headache patients also reported significantly more frequent and intense tooth contact, more masticatory muscle tension, more stress and more pain in the face/head and other parts of the body than non-headache controls. These results are similar to those reported for TMD patients and they suggest that headache patients and TMD patients overlap considerably in diagnosis and oral parafunctional behaviours.


2020 ◽  
Vol 8 (4) ◽  
pp. 132
Author(s):  
Daisuke Sugihara ◽  
Misao Kawara ◽  
Hiroshi Suzuki ◽  
Takashi Asano ◽  
Akihiro Yasuda ◽  
...  

The examination of jaw movement during exercise is essential for an improved understanding of jaw function. Currently, there is no unified view of the mechanism by which the mandible is fixed during physical exercise. We hypothesized that during strong skeletal muscle force exertion in dynamic exercises, the mandible is displaced to a position other than the maximal intercuspal position and that mouth-opening and mouth-closing muscles simultaneously contract to fix the displaced mandible. Therefore, we simultaneously recorded mandibular jaw movements and masticatory muscle activities during dynamic trunk muscle force exertion (deadlift exercise) in 24 healthy adult males (age, 27.3 ± 2.58 years). The deadlift was divided into three steps: Ready (reference), Pull, and Down. During Pull, the mandibular incisal point moved significantly posteriorly (−0.24 mm, p = 0.023) and inferiorly (−0.55 mm, p = 0.019) from the maximal intercuspal position. Additionally, temporal, masseter, and digastric muscles were activated simultaneously and significantly during Pull (18.63 ± 17.13%, 21.21 ± 18.73%, 21.82 ± 19.97% of the maximum voluntary contraction, respectively), with maintained activities during Down (p < 0.001). Thus, during dynamic trunk muscle force exertion, the mandibular incisal point moved to a posteroinferior position without tooth-touch (an open-mouth position). Simultaneously, the activities of the mouth-opening digastric muscles and the mouth-closing temporal and masseter muscles led to mandibular fixation, which is a type of mandible fixing called bracing.


1997 ◽  
Vol 40 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Virginia A. Hinton ◽  
Winston M. C. Arokiasamy

It has been hypothesized that typical speech movements do not involve large muscular forces and that normal speakers use less than 20% of the maximum orofacial muscle contractile forces that are available (e.g., Amerman, 1993; Barlow & Abbs, 1984; Barlow & Netsell, 1986; DePaul & Brooks, 1993). However, no direct evidence for this hypothesis has been provided. This study investigated the percentage of maximum interlabial contact pressures (force per unit area) typically used during speech production. The primary conclusion of this study is that normal speakers typically use less than 20% of the available interlabial contact pressure, whether or not the jaw contributes to bilabial closure. Production of the phone [p] at conversational rate and intensity generated an average of 10.56% of maximum available interlabial pressure (MILP) when jaw movement was not restricted and 14.62% when jaw movement was eliminated.


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