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Sample records for masseter temporalis digastric

  1. Asymmetric activation of temporalis, masseter, and sternocleidomastoid muscles in temporomandibular disorder patients.

    PubMed

    Ries, Lilian Gerdi Kittel; Alves, Marcelo Correa; Bérzin, Fausto

    2008-01-01

    The aim of this study was to analyze the symmetry of the electromyographic (EMG) activity of the temporalis, masseter, and sternocleidomastoid (SCM) muscles in volunteers divided into a control group and a temporomandibular disorder (TMD) group. The surface EMG recordings were made during mandibular rest position, maximal intercuspal position, and during the chewing cycle. Normalized EMG waves of paired muscles were compared by computing a percentage overlapping coefficient (POC). The difference between the groups and between the static and dynamic clenching tests was analyzed through repeated measures, ANOVA. Symmetry of the temporalis, masseter, and SCM muscles activity was smaller in the TMD group compared to the control group. The mandibular postures were also significantly different among themselves. The asymmetric activation of jaw and neck muscles was interpreted as a compensatory strategy to achieve stability for the mandibular and cervical systems during masticatory function. PMID:18290526

  2. The Predictability from Skull Morphology of Temporalis and Masseter Muscle Cross-Sectional Areas in Humans.

    PubMed

    Toro-Ibacache, Viviana; Zapata MuÑoz, Victor; O'higgins, Paul

    2015-07-01

    To carry out functional simulations of the masticatory system that aim to predict strain magnitudes it is important to apply appropriate jaw-elevator muscle forces. Force magnitude estimation from directly measured muscle physiological cross-sectional area or anatomical cross-sectional area (CSA) is not possible for fossils and skeletal material from museum collections. In these cases, muscle CSAs are often estimated from bony features. This approach has been shown to be inaccurate in a prior study based on direct measurements from cadavers. Postmortem alterations as well as age changes in muscle form might explain this discrepancy. As such, the present study uses CT images from 20 living individuals to directly measure temporalis and masseter muscle CSAs and estimated cross-sectional areas (ECSAs) from bony features. The relationships between CSAs and ECSAs were assessed by comparing mean values and by examining correlations. ECSAs are up to 100% greater than CSA and the means of these variables for each muscle differ significantly. Further, ECSA is significantly correlated with CSA for temporalis but not masseter. Cranial centroid size is only significantly associated with CSA for temporalis. These findings indicate that ECSAs should be employed with caution in simulations of human masticatory system functioning; they do not reflect CSAs and it is plausible that this also applies to studies of closely related living and fossil taxa. When ECSAs are used, sensitivity analyses are required to determine the impact of potential errors. PMID:25810234

  3. Effect of tongue position on masseter and temporalis electromyographic activity during swallowing and maximal voluntary clenching: a cross-sectional study.

    PubMed

    Valdés, C; Astaburuaga, F; Falace, D; Ramirez, V; Manns, A

    2014-12-01

    The purpose of this study was to measure and compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles following placement of the tongue either on the palate or in the floor of the mouth during swallowing and maximal voluntary clenching (MVC). Thirty healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth or tongue participated in the study. Tonic masseter and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth during swallowing and MVC. At each tongue position, the resulting EMG was recorded. During swallowing, no significant difference in EMG activity was found either for the masseter (P-value = 0.1592) or the temporalis (P-value = 0.0546) muscles, regardless of the tongue position. During MVC, there was a statistically significant difference for both the masseter (P-value = 0.0016) and the temporalis (P-value = 0.0277) muscles with lower levels recorded with the tongue in the floor of the mouth. This study found that in normal, pain-free subjects, placing the tongue in the floor of the mouth significantly reduces masticatory muscle activity during MVC. Thus, it may be considered as a possible therapeutic option to decrease masticatory muscle activity; however, further research is needed in patients with oro-facial pain. PMID:25040648

  4. [Electromyographic silent period in the masseter and temporal muscles].

    PubMed

    Perrin, M; Yardin, M

    1978-09-01

    For some years, many authors have studied the silent periods (S.P.) in masticatory human muscles, during voluntary clenching, biting or mastication as well as during electrical or mechanical stimulation of various parts of the mouth. This S.P. appears as a flattening in the electromyograph tracing taken from masseter and temporalis anterior muscles simultaneously. After an analysis of the methods and results of previous authors, we give and discuss our result, obtained from records on masseter and temporalis anterior muscles, on right and left sides, on healthy subjects. They tapped first their teeth, then masticated pea-nuts, pieces of apple and soft bread. We obtained 571 S.P. after recording 1 745 cycles, and in contrary to the opinion of most of the authors, we were not able to obtain simultaneous S.P. in all four muscles at every cycle, except on 26 occasions. To conclude, we discuss our observations and suggest pathways for the inhibiting reflex of masticatory muscles during functions. PMID:282287

  5. Myositis Ossificans of the Temporalis Muscle.

    PubMed

    Becker, Otávio Emmel; Avelar, Rafael Linard; Rivero, Elena Riet Correa; De Oliveira, Rogério Belle; Meurer, Maria Inês; Santos, Aira Maria Bonfim; Haas Júnior, Orion Luis; Meurer, Eduardo

    2016-09-01

    Traumatic myositis ossificans (TMO) is a rare ossifying disease that occurs in the muscle or soft tissues. A case of TMO isolated in the temporalis muscle is reported. In the case described, calcification in the temporalis muscle was confirmed after computed tomography. Surgery, physiotherapy, and histopathological analysis were performed. One year after treatment, further ossification was present but without interference in function. The most accepted treatment for TMO in the maxillofacial region is excision followed by physiotherapy. The high rate of non-recurrence may be concealed due to the short follow-up period. TMO is a lesion that may frequently recur and long-term follow-up must be provided. PMID:26703385

  6. Digastric Muscle Phenotypes of the Ts65Dn Mouse Model of Down Syndrome.

    PubMed

    Glass, Tiffany J; Connor, Nadine P

    2016-01-01

    Down syndrome is frequently associated with complex difficulties in oromotor development, feeding, and swallowing. However, the muscle phenotypes underlying these deficits are unclear. We tested the hypotheses that the Ts65Dn mouse model of DS has significantly altered myosin heavy chain (MyHC) isoform profiles of the muscles involved in feeding and swallowing, as well as reductions in the speed of these movements during behavioral assays. SDS-PAGE, immunofluorescence, and qRT-PCR were used to assess MyHC isoform expression in pertinent muscles, and functional feeding and swallowing performance were quantified through videofluoroscopy and mastication assays. We found that both the anterior digastric (ADG) and posterior digastric (PDG) muscles in 11-day old and 5-6 week old Ts65Dn groups showed significantly lower MyHC 2b protein levels than in age-matched euploid control groups. In videofluoroscopic and videotape assays used to quantify swallowing and mastication performance, 5-6 week old Ts65Dn and euploid controls showed similar swallow rates, inter-swallow intervals, and mastication rates. In analysis of adults, 10-11 week old Ts65Dn mice revealed significantly less MyHC 2b mRNA expression in the posterior digastric, but not the anterior digastric muscle as compared with euploid controls. Analysis of MyHC 2b protein levels across an adult age range (10-53 weeks of age) revealed lower levels of MyHC 2b protein in the PDG of Ts65Dn than in euploids, but similar levels of MyHC 2b in the ADG. Cumulatively, these results indicate biochemical differences in some, but not all, muscles involved in swallowing and jaw movement in Ts65Dn mice that manifest early in post-natal development, and persist into adulthood. These findings suggest potential utility of this model for future investigations of the mechanisms of oromotor difficulties associated with Down syndrome. PMID:27336944

  7. Digastric Muscle Phenotypes of the Ts65Dn Mouse Model of Down Syndrome

    PubMed Central

    Connor, Nadine P.

    2016-01-01

    Down syndrome is frequently associated with complex difficulties in oromotor development, feeding, and swallowing. However, the muscle phenotypes underlying these deficits are unclear. We tested the hypotheses that the Ts65Dn mouse model of DS has significantly altered myosin heavy chain (MyHC) isoform profiles of the muscles involved in feeding and swallowing, as well as reductions in the speed of these movements during behavioral assays. SDS-PAGE, immunofluorescence, and qRT-PCR were used to assess MyHC isoform expression in pertinent muscles, and functional feeding and swallowing performance were quantified through videofluoroscopy and mastication assays. We found that both the anterior digastric (ADG) and posterior digastric (PDG) muscles in 11-day old and 5–6 week old Ts65Dn groups showed significantly lower MyHC 2b protein levels than in age-matched euploid control groups. In videofluoroscopic and videotape assays used to quantify swallowing and mastication performance, 5–6 week old Ts65Dn and euploid controls showed similar swallow rates, inter-swallow intervals, and mastication rates. In analysis of adults, 10–11 week old Ts65Dn mice revealed significantly less MyHC 2b mRNA expression in the posterior digastric, but not the anterior digastric muscle as compared with euploid controls. Analysis of MyHC 2b protein levels across an adult age range (10–53 weeks of age) revealed lower levels of MyHC 2b protein in the PDG of Ts65Dn than in euploids, but similar levels of MyHC 2b in the ADG. Cumulatively, these results indicate biochemical differences in some, but not all, muscles involved in swallowing and jaw movement in Ts65Dn mice that manifest early in post-natal development, and persist into adulthood. These findings suggest potential utility of this model for future investigations of the mechanisms of oromotor difficulties associated with Down syndrome. PMID:27336944

  8. Microvascular temporalis fascia transfer for penile girth enhancement.

    PubMed

    Küçükçelebi, A; Ertaş, N M; Aydin, A; Eroğlu, A; Ozmen, E; Velidedeoğlu, H

    2001-07-01

    The authors report a 44-year-old man with inadequate penile girth that caused psychological problems. Using microvascular temporalis fascia transfer, they achieved satisfactory penile girth enhancement based on reliable vascularity in a single stage. PMID:11756810

  9. Myosin heavy chain composition of the human lateral pterygoid and digastric muscles in young adults and elderly.

    PubMed

    Monemi, M; Liu J-X; Thornell, L E; Eriksson, P O

    2000-05-01

    The myosin heavy chain (MyHC) content in different parts of, two jaw opening muscle, the human lateral pterygoid and the digastric muscles of five young adult and five elderly subjects (mean age 22 and 73 years, respectively) was determined, using gel electrophoresis and immunohistochemical methods. The lateral pterygoid of both young and elderly contained predominantly slow MyHC, and fast A MyHC was the major fast isoform. In contrast, the digastric was composed of slow, fast A and fast X MyHCs in about equal proportions in both age groups. About half of the lateral pterygoid fibres contained mixtures of slow and fast MyHCs, often together with alpha-cardiac MyHC. In the digastric, co-existence of slow and fast MyHCs was rare, and alpha-cardiac MyHC was lacking. On the other hand, co-expression of fast A and fast X MyHCs was found more often in the digastric than in the lateral pterygoid. In both age groups about half of the digastric IIB fibres contained solely fast X MyHC. In the lateral pterygoid, type IIB fibres with pure fast X MyHC was found in only one subject. The lateral pterygoid in elderly showed a significant amount of fibres with solely fast A MyHC, which were occasionally found in young adults. In the digastric, no significant differences were found between young and elderly, although the muscles of elderly contained lower mean value of slow MyHC, as compared to that of young muscles. It is concluded that the lateral pterygoid and the digastric muscles differ not only in the MyHC composition but also in modifications of the MyHC phenotypes during aging, suggesting that they have separate roles in jaw opening function. PMID:11032341

  10. The laminar structure of the common opossum masseter (Didelphis marsupialis).

    PubMed

    Deguchi, T; Takemura, A; Suwa, F

    2001-03-01

    Using three heads of the common opossum (Didelphis marsupialis), which may be considered to have a primitive mammalian form and therefore be appropriate for this study, the laminar structure of the masseter was investigated. We also attempted a comparative anatomical study of the relationships of food habits to the laminar structures of the masseter, zygomatic arch and mandibular ramus. In the common opossum masseter, a total of six layers, the primary and secondary sublayers of the superficial layer, the intermediate layer, and the primary, secondary and third sublayers of the deep layer as a proper masseter, were observed. These layers showed a typical reverse laminar structure, with the layers of tendons and muscles alternating. The maxillomandibularis and zygomaticomandibularis muscles were observed in one layer each, as an improper masseter. The laminar structure of the common opossum masseter was shown to be more similar to that of carnivorous placental animals than that of the herbivorous red kangaroo, a similar marsupial. In regard to the number of layers in the laminar structure of the masseter, the results of both this study and those of our predecessors' showed that differences in food habits affect the deep layer in the proper masseter of marsupials and placental mammals, and that of the maxillomandibularis muscle of placental mammals in the improper masseter. PMID:11392012

  11. Morphometrics of the Anterior Belly and Intermediate Tendon of the Digastric Muscle: Sexual Dimorphism and Implications for Surgery.

    PubMed

    Zdilla, Matthew J; Pancake, Alex R; Lambert, H Wayne

    2016-07-01

    The anterior belly of the digastric muscle (ABDM) is important in a variety of surgeries including submental lipectomy, rhytidectomy, alteration of the cervicomental angle via muscle resection, the "digastric corset" procedure for submental rejuvenation, the submental artery flap, and reanimation of the mouth after facial nerve palsy. Despite its clinical significance, little information exists regarding the morphometrics of the ABDM or its associated intermediate tendon. This study analyzed a total of 35 intact ABDMs and 43 intact intermediate tendons from 23 cadavers. Measurements were taken of the following parameters: muscle belly area, muscle belly length, intermediate tendon length, and intermediate tendon width at mid-tendon. Normative descriptive statistics are included within the report. Males were found to have significantly longer left-sided muscle bellies than right-sided bellies from males (U = 23.0; P = 0.044), left-sided bellies from females (U = 19.0; P = 0.020), and right-sided bellies from females (U = 12.0; P = 0.035). The morphometry, including sexual dimorphism, presented in this report can aid in the surgical planning and execution of numerous operations performed in head and neck, especially digastric muscle transfer surgery. PMID:27258716

  12. Presumptive Intramuscular Hemangioma of the Masseter Muscle

    PubMed Central

    Alami, Badreeddine; Lamrani, Youssef; Addou, Omar; Boubbou, Meryem; Kamaoui, Imane; Maaroufi, Mustapha; Sqalli, Nadia; Tizniti, Siham

    2015-01-01

    Patient: Male, 34 Final Diagnosis: Intramuscular hemangioma of the masseter muscle Symptoms: Swelling over parotid region Medication: — Clinical Procedure: Clinical-Radiological work-up Specialty: Radiology Objective: Rare disease Background: Hemangioma is a benign vascular proliferation. Intramuscular hemangiomas are rare, accounting for less than 1% of all hemangiomas, and occur normally in the trunk and extremities. Approximately 10–20% of intramuscular hemangiomas are found in the head and neck region, most often in the masseter muscles. The typical clinical characteristic is a painful soft tissue mass without cutaneous changes. Currently, MRI is the standard imaging technique for diagnosing soft-tissue hemangioma. The optimal management is the surgical resection. Case Report: We report a case of 34-year-old male patient consulted for a swelling of 1 year evolution, around the parotid region. On physical examination, a soft, well-contoured lesion of about 2 cm on its long axis was found. MRI showed a space-occupying lesion in the left masseter muscle, with intermediate signal intensity on T1-weighted images and hyperignal intensity on T2-weighted images, containing nodular hypointense foci corresponding to calcification. The presumptive diagnosis of an intramasseteric hemangioma with phlebolith was made based on these findings. The patient was informed about her condition, and treatment options were discussed; however, the patient elected to forgo treatment at that time. Conclusions: The possibility of an IMH should be included in the differential diagnosis of any intra-masseteric lesion. The appropriate radiologic examinations especially MRI can enhance accurate preoperative diagnosis; the treatment of choice should be individualized in view of the clinical status of the patient. PMID:25590509

  13. Esterase profile of human masseter muscle.

    PubMed Central

    Kirkeby, S; Moe, D; Vilmann, H

    1988-01-01

    The esterase profile of fresh human masseter muscle was investigated by use of histochemistry and electrophoresis. The histochemical methods included reactions for alpha-naphthyl esterase, myofibrillar ATPase, reverse myofibrillar ATPase and succinic dehydrogenase. In frozen sections of the muscle the coloured reaction product for esterases was present both as a diffuse sarcoplasmic coloration and as distinct granules. The intensity of diffuse reaction was used to classify the muscle fibres as strongly, moderately and weakly reacting. The fibres with strong esterase activity belonged to Type I and iiC. iM and Type II A fibres showed a moderate esterase reaction and Type II B fibres had a low activity. The electrophoretic gels stained for esterase activity showed that the human masseter muscle possesses a slow migrating double band with high enzyme activity and a cascade of faster migrating isoenzymes. In isoelectric focused gels the major esterases showed isoelectric points around pH 5. Images Fig. 1 Fig. 2 Figs. 3-5 Figs. 6-8 Figs. 9-11 Figs. 12-14 Figs. 15-16 Fig. 17 PMID:3198486

  14. Silicone vs temporalis fascia interposition in TMJ ankylosis: A comparison

    PubMed Central

    Gupta, Sumit; Gupta, Hemant; Mohammad, Shadab; Mehra, Hemant; Natu, Subodh Shankar; Gupta, Niharika

    2016-01-01

    Objective Temporomandibular joint ankylosis (TMJa) is a distressing condition, but can be surgically managed by gap or interpositional arthroplasty, with an aim to restore joint function and prevent re-ankylosis. The aim of this paper is to compare two interposition materials used in management of TMJ ankylosis. Methods 15 patients with TMJa were randomly allocated to two groups: group A (n = 6), interposition material used was medical-grade silicon elastomer, and group B (n = 9) where the interposition material used was temporalis fascia. Patients were followed up at regular intervals of 1 and 2 weeks, 1 month, 3 months, and 6 months and were assessed on following parameters: pain by VAS Scale, maximal mouth opening (MMO), implant rejection, and recurrence. Results The results showed a loss of 4.6% and 7.9% in maximal interincisal mouth opening at 3rd and 6th months in Group A while Group B had a mean loss of 9% and 10% at 3rd and 6th months respectively without any significant difference. None of our cases showed recurrence or implant rejection. Conclusion We conclude that silicone is comparable to temporalis fascia in terms of stability, surgical ease, and adaptability. It not only restores the function of mandible and ensures good maximum interincisal opening but also maintains the vertical ramal height. Also, it requires less operating time and is easy to handle but is not economical. It might be an effective way to restore function and prevent re-ankylosis. PMID:27195207

  15. Correction of post-traumatic anterior open bite by injection of botulinum toxin type A into the anterior belly of the digastric muscle: case report

    PubMed Central

    Park, Yong-Tae; Kim, Seong-Gon; Park, Young-Wook

    2013-01-01

    Post-traumatic anterior open bite can occur as a result of broken balance among the masticatory muscles. The superior hyoid muscle group retracts the mandible downward and contributes to the anterior open bite. Denervation of the digastric muscle by injection of botulinum toxin type A (BTX-A) can reduce the power of the digastric muscle and help to resolve the post-traumatic anterior open bite. A patient with a bilateral angle fracture had an anterior open bite even after undergoing three operations under general anesthesia and rubber traction. Although the open bite showed some improvement by the repeated operation, the occlusion was still unstable six weeks after the initial treatment. To eliminate the residual anterior open bite, BTX-A was injected into the anterior belly of the digastric muscle. Following injection of BTX-A, the anterior open bite showed immediate improvement. Complication and relapse were not observed during follow-up. Long-standing post-traumatic open bite could be successfully corrected by injection of BTX-A into the anterior belly of the digastric muscle without complication. PMID:24471041

  16. Glutamate-induced sensitization of rat masseter muscle fibers.

    PubMed

    Cairns, B E; Gambarota, G; Svensson, P; Arendt-Nielsen, L; Berde, C B

    2002-01-01

    In rats, intradermal or intraarticular injection of glutamate or selective excitatory amino acid receptor agonists acting at peripheral excitatory amino acid receptors can decrease the intensity of mechanical stimulation required to evoke nocifensive behaviors, an indication of hyperalgesia. Since excitatory amino acid receptors have been found on the terminal ends of cutaneous primary afferent fibers, it has been suggested that increased tissue glutamate levels may have a direct sensitizing effect on primary afferent fibers, in particular skin nociceptors. However, less is known about the effects of glutamate on deep tissue afferent fibers. In the present study, a series of experiments were undertaken to investigate the effect of intramuscular injection of glutamate on the excitability and mechanical threshold of masseter muscle afferent fibers in anesthetized rats of both sexes. Injection of 1.0 M, but not 0.1 M glutamate evoked masseter muscle afferent activity that was significantly greater than that evoked by isotonic saline. The mechanical threshold of masseter muscle afferent fibers, which was assessed with a Von Frey hair, was reduced by approximately 50% for a period of 30 min after injection of 1.0 M glutamate, but was unaffected by injections of 0.1 M glutamate or isotonic saline. Injection of 25% dextrose, which has the same osmotic strength as 1.0 M glutamate, did not evoke significant activity in or decrease the mechanical threshold of masseter muscle afferent fibers. Magnetic resonance imaging experiments confirmed that injection of 25% dextrose and 1.0 M glutamate produced similar edema volumes in the masseter muscle tissue. Co-injection of 0.1 M kynurenate, an excitatory amino acid receptor antagonist, and 1.0 M glutamate attenuated glutamate-evoked afferent activity and prevented glutamate-induced mechanical sensitization. When male and female rats were compared, no difference in the baseline mechanical threshold or in the magnitude of glutamate

  17. The blood supply of the human temporalis muscle: a vascular corrosion cast study.

    PubMed Central

    Cheung, L K

    1996-01-01

    Knowledge as to the blood supply of the human temporalis muscle is limited to its extramuscular path and relations, little information existing about the intramuscular vascular architecture. To investigate the 3-dimensional vascular network in the human temporalis muscle, in 5 fresh cadavers an infusion of methylmethacrylate resin was made via the carotid vessels with subsequent removal of the organic tissues by a corrosion process. The vascular corrosion casts of the temporalis muscle were studied by stereomicroscopy and scanning electron microscopy. In 6 well perfused muscle specimens, the temporalis muscle was found to be consistently supplied by 3 arteries: the anterior and posterior deep temporal arteries, and the middle temporal artery. Each primary artery branched into the secondary arterioles and then terminal arterioles. The venous network accompanied the arteries, and double veins pairing a single artery was a common finding. Arteriovenous anastomosis was absent, whereas arterioarterial and venovenous anastomoses were common. The capillaries formed a dense interlacing network with an orientation along the muscle fibres. Understanding of the intramuscular angioarchitecture of the temporalis provides the vascular basis for surgical flap manipulation and splitting design. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8886964

  18. Higher masseter muscle mass in grazing than in browsing ruminants.

    PubMed

    Clauss, Marcus; Hofmann, Reinold R; Streich, W Jürgen; Fickel, Jörns; Hummel, Jürgen

    2008-09-01

    Using cranioskeletal measurements, several studies have generated evidence that grazing ruminants have a more pronounced mastication apparatus, in terms of muscle insertion areas and protuberances, than browsing ruminants, with the resulting hypothesis that grazers should have larger, heavier chewing muscles than browsers. However, the only investigation of this so far [Axmacher and Hofmann (J Zool 215:463-473, 1988)] did not find differences between ruminant feeding types in the masseter muscle mass of 22 species. Here, we expand the dataset to 48 ruminant species. Regardless of phylogenetic control in the statistical treatment, there was a significant positive correlation of body mass and masseter mass, and also a significant association between percent grass in the natural diet and masseter mass. The results support the concept that ruminant species that ingest more grass have relatively larger masseter muscles, possibly indicating an increased requirement to overcome the resistance of grass forage. The comparative chewing resistance of different forage classes may represent a rewarding field of ecophysiological research. PMID:18612652

  19. Histochemical and functional fibre typing of the rabbit masseter muscle.

    PubMed Central

    Bredman, J J; Weijs, W A; Moorman, A F; Brugman, P

    1990-01-01

    The fibre-type distribution of the masseter muscle of the rabbit was studied by means of the myosin-ATPase and succinate dehydrogenase reactions. Six different fibre types were found and these were unequally distributed between and within the anatomical compartments of the muscle. Most of the masseter consists of slow- and fast-twitch oxidative fibres. The slow fibres increase in numbers in the deeper and more anterior regions of the muscle. Fast-twitch glycolytic fibres were almost exclusively found in the most posterior portions of the superficial and deep masseter. The fibre composition within the sagittally orientated anatomical compartments was found to be correlated with maximal contraction speeds during natural mastication as estimated from a mechanical model. However, the differences in fibre composition between the anatomical compartments (and hence between superficial and deep layers) appeared not to be correlated with contraction speed. The regional and compartmental specialisation within the masseter permits the muscle to perform many different functional roles in the generation and control of the jaw movements, jaw position and bite forces. Images Fig. 2 Fig. 4 Fig. 6 PMID:2139021

  20. The "temporalis-inhibitory reflex" in post-lumbar puncture headache.

    PubMed

    Wallasch, T M; Niemann, U; Strenge, H

    1992-01-01

    Nausea and rigidity of the neck muscles, typical symptoms of post-lumbar puncture syndrome (PPS), may also be found in patients suffering from chronic headache of the tension-type. A decreased duration of the late suppression period of temporal muscle activity indicating a central disturbance of pericranial muscle control, can be observed in these patients. We have studied the temporalis-inhibitory reflex in 47 neurological inpatients requiring lumbar puncture. There were no significant differences of latencies or durations of temporalis silent periods between patients with and without PPS before, and 48 h following, lumbar puncture. PMID:1292957

  1. Morphofunctional Compensation of Masseter Muscles in Unilateral Posterior Crossbite Patients

    PubMed Central

    Cutroneo, G.; Vermiglio, G.; Centofanti, A.; Rizzo, G.; Runci, M.; Favaloro, A.; Piancino, M.G.; Bracco, P.; Ramieri, G.; Bianchi, F.; Speciale, F.; Arco, A.; Trimarchi, F.

    2016-01-01

    Unilateral posterior crossbite is a widespread, asymmetric malocclusion characterized by an inverse relationship of the upper and lower buccal dental cusps, in the molar and premolar regions, on one side only of the dental arch. Patients with unilateral posterior crossbite exhibit an altered chewing cycles and the crossbite side masseter results to be less active with respect to the contralateral one. Few studies about morphological features of masticatory muscle in malocclusion disorders exist and most of these have been performed on animal models. The aim of the present study was to evaluate morphological and protein expression characteristics of masseter muscles in patients affected by unilateral posterior crossbite, by histological and immunofluorescence techniques. We have used antibody against PAX-7, marker of satellite cells, and against α-, β-, γ-, δ-, ε- and ζ-sarcoglycans which are transmembrane glycoproteins involved in sarcolemma stabilization. By statistical analysis we have evaluated differences in amount of myonucley between contralateral and ipsilateral side. Results have shown: i) altered fibers morphology and atrophy of ipsilateral muscle if compared to the contralateral one; ii) higher number of myonuclei and PAX-7 positive cells in contralateral side than ipsilateral one; iii) higher pattern of fluorescence for all tested sarcoglycans in contralateral side than ipsilateral one. Results show that in unilateral posterior crossbite hypertrophic response of contralateral masseter and atrophic events in ipsilateral masseter take place; by that, in unilateral posterior crossbite malocclusion masticatory muscles modify their morphology depending on the function. That could be relevant in understanding and healing of malocclusion disorders; in fact, the altered balance about structure and function between ipsilateral and contralateral muscles could, long-term, lead and/ or worsen skeletal asymmetries. PMID:27349311

  2. Comparison of Modified Cartilage Shield Tympanoplasty with Tympanoplasty Using Temporalis Fascia Only: Retrospective Analysis of 142 Cases

    PubMed Central

    Parikh, Vibhuti; Shah, Saumya; Pandya, Parita; Kansara, Anuj

    2016-01-01

    The current study compares outcomes of modified cartilage shield tympanoplasty (CST) with temporalis fascia tympanoplasty in type I procedures in Indian patients. Graft uptake rates are better with the CST technique and hearing results are almost equivalent with both techniques except at 8000 Hz where improvement in hearing was found better with the use of temporalis fascia alone. The CST technique used in the study is unique. PMID:27559489

  3. State-dependent phenomena in cat masseter motoneurons.

    PubMed

    Kohlmeier, K A; López-Rodríguez, F; Liu, R H; Morales, F R; Chase, M H

    1996-05-25

    In the present study we explored the mechanisms of carbachol-induced muscle atonia in the alpha-chloralose-anesthetized animal. We compared our findings to those that have been previously obtained in unanesthetized cats during muscle atonia occurring during natural active sleep. Accordingly, in cats anesthetized with alpha-chloralose, intracellular records were obtained from masseter motoneurons before and after carbachol-induced motor atonia. Following the induction of atonia, the membrane potential activity was dominated by high-frequency, discrete, hyperpolarizing potentials. These hyperpolarizing potentials were reversed in polarity by the intracellular injection of chloride ions and abolished by the application of strychnine. These findings indicate that they were inhibitory postsynaptic potentials (IPSPs) mediated by glycine. These IPSPs appeared exclusively during muscle atonia. In addition, masseter motoneurons were significantly hyperpolarized and their rheobase increased. There was a decrease in input resistance and membrane time constant. In the alpha-chloralose-anesthetized preparation, stimulation of the nucleus pontis oralis (NPO) induced IPSPs in masseter motoneurons following, but never prior to, the pontine injection of carbachol. Thus, this is the first demonstration that "reticular response-reversal' may be elicited in an anesthetized preparation. Another state-dependent phenomenon of active sleep, the occurrence of IPSPs in motoneurons that are temporally correlated with ponto-geniculo-occipital (PGO) waves, was also observed in this preparation only after carbachol administration. Based on the data in this report, we conclude that the inhibitory system that mediates atonia during the state of active sleep can be activated in an animal that is anesthetized with alpha-chloralose. Specifically, the neuronal groups that generate spontaneous IPSPs, those that mediate the phenomenon of reticular response-reversal, and those involved in the generation

  4. Functional Compartmentalization of the Human Superficial Masseter Muscle

    PubMed Central

    Guzmán-Venegas, Rodrigo A.; Biotti Picand, Jorge L.; de la Rosa, Francisco J. Berral

    2015-01-01

    Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle’s motor units using high-density surface electromyography (EMGs) at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm) were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF) were randomly requested. Using a two-dimensional grid (four columns, six electrodes) located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001).The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001). The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001). The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20–60% MVBF). PMID:25692977

  5. Differential Response of Pig Masseter to Botulinum Neurotoxin Serotypes A and B

    PubMed Central

    Liu, Zi-Jun; Rafferty, Katherine L.; Ye, Wenmin; Herring, Susan W.

    2014-01-01

    Introduction Pigs respond to direct administration of botulinum neurotoxins (BoNTs), although they are resistant to botulism. The human masseter is frequently targeted for BoNT therapy. We aimed to understand how BoNT affects chewing by injecting porcine masseters. Methods One masseter of minipigs was injected with BoNT serotype A or B at doses comparable to those used in humans. Masticatory function was evaluated electromyographically. Muscle force was measured during tetany. Four weeks after injection, strain gauges affixed to the mandible assessed bone strain during chewing. Masseter mass and fiber diameter were measured after euthanasia. Results BoNT-A had no measurable effect. In contrast, BoNT-B reduced electrical activity and muscle force, producing substantial asymmetry between injected and uninjected muscles. Discussion The pig masseter is highly resistant to direct injection of BoNT-A, but it is affected by BoNT-B. PMID:26039454

  6. Masseter muscle rigidity: Atypical malignant hyperthermia presentation or isolated event?

    PubMed Central

    Onyeka, Tonia C. U.

    2010-01-01

    This report describes a case of masseter muscle rigidity encountered at the start of an elective gynaecological procedure. At preoperative assessment, the patient, a 41-year old woman with a previous non-eventful surgical and anesthetic history was given a Mallampati score of 3. Following suxamethonium administration, full mouth opening proved difficult. Laryngoscopy and tracheal intubation were not possible leading to the eventual use of a laryngeal mask airway and resulting in a successful anaesthetic outcome. A number of possibilities that may account for this situation as well as viable options for airway access in such cases are discussed below. PMID:21189861

  7. The superficial temporal fat pad and its ramifications for temporalis muscle construction in facial approximation.

    PubMed

    Stephan, Carl N; Devine, Matthew

    2009-10-30

    The construction of the facial muscles (particularly those of mastication) is generally thought to enhance the accuracy of facial approximation methods because they increase attention paid to face anatomy. However, the lack of consideration for non-muscular structures of the face when using these "anatomical" methods ironically forces one of the two large masticatory muscles to be exaggerated beyond reality. To demonstrate and resolve this issue the temporal region of nineteen caucasoid human cadavers (10 females, 9 males; mean age=84 years, s=9 years, range=58-97 years) were investigated. Soft tissue depths were measured at regular intervals across the temporal fossa in 10 cadavers, and the thickness of the muscle and fat components quantified in nine other cadavers. The measurements indicated that the temporalis muscle generally accounts for <50% of the total soft tissue depth, and does not fill the entirety of the fossa (as generally known in the anatomical literature, but not as followed in facial approximation practice). In addition, a soft tissue bulge was consistently observed in the anteroinferior portion of the temporal fossa (as also evident in younger individuals), and during dissection, this bulge was found to closely correspond to the superficial temporal fat pad (STFP). Thus, the facial surface does not follow a simple undulating curve of the temporalis muscle as currently undertaken in facial approximation methods. New metric-based facial approximation guidelines are presented to facilitate accurate construction of the STFP and the temporalis muscle for future facial approximation casework. This study warrants further investigations of the temporalis muscle and the STFP in younger age groups and demonstrates that untested facial approximation guidelines, including those propounded to be anatomical, should be cautiously regarded. PMID:19632798

  8. Relaxation rate in the assessment of masseter muscle fatigue.

    PubMed

    Lyons, M F; Aggarwal, A

    2001-02-01

    The aim of this study was to assess a simple method of measuring relaxation rate in the jaw-closing system for the purpose of quantifying jaw muscle fatigue. A summary of the various different methods of measuring relaxation rate is also provided. The rates of twitch contraction and relaxation were measured in 30 symptom-free subjects following bilateral direct electrical stimulation of the masseter muscles. The resulting twitch force was recorded via a force transducer placed between the anterior teeth. The transducer was held between the teeth with as little force as possible while four single stimuli were delivered at 5-s intervals. The stimulating electrodes were then removed and replaced and the experiment was repeated. The force records of the resulting twitches were averaged and the half-contraction time, twitch amplitude and half-relaxation time were measured. There was a significant difference in half-relaxation time between males and females, being faster in females (P=0.0045, independent t-test). No significant difference was found in twitch amplitude and half-contraction time between males and females. Half-relaxation time and half-contraction time were independent of twitch amplitude. This method of measuring the relaxation rate of the masseter muscles was found to be practical and the results were reproducible between sessions. PMID:11298267

  9. A cineradiographic and electromyographic study of mastication in Tenrec ecaudatus.

    PubMed

    Oron, U; Crompton, A W

    1985-08-01

    Regular chewing was studied in the specialized Malagasy insectivore Tenrec ecaudatus with the aid of precisely correlated electromyography of the main adductors, digastrics, and two hyoid muscles and cineradiography for which metallic markers were placed in the mandibles, tongue, and hyoid bone. During the power stroke the body of the mandible moves dorsally and medially. The medially directed component of movement at this time is greatly increased by simultaneous rotation of the mandible about its longitudinal axis. The highly mobile symphysis, spherical dentary condyle, loss of superficial masseter muscle and zygoma, and the simplified zalamnodont molars all appear to be related to the large amount of mandibular rotation that occurs during occlusion. The balancing side lateral pterygoid muscle (inferior head) apparently shifts the working side mandible laterally during the last part of opening and the first part of closing. The working side temporalis and the superficial masseter muscle are both responsible for the shift back to the midline. The temporalis is usually active to the same extent on the working and balancing sides during the power stroke. The level of activity (amplitude) of the temporalis and duration of the power stroke increase with harder foods. Whenever soft foods are chewed, the superficial masseter is only active on the working side; whenever foods of increasing hardness are chewed, its level of activity on the balancing side increases to approach that of the working side. Mandibular rotation is greatly reduced when hard foods are chewed. PMID:4057264

  10. A phlebolith in the anterior portion of the masseter muscle.

    PubMed

    Kato, Hisashi; Ota, Yoshihide; Sasaki, Masashi; Arai, Toshihiro; Sekido, Yasutomo; Tsukinoki, Keiichi

    2012-04-01

    The differential diagnosis of a buccal soft tissue mass containing calcified bodies includes a phlebolith associated with a vascular lesion, such as a hemangioma with a calcified intravascular thrombus, and diseases such as sialolithiasis, traumatic myositis ossificans, calcified acne lesion, neoplasm, and calcified lymph nodes, including tuberculosis. The appearance of the calcified bodies on plain radiographs may help to differentiate these entities. Computed tomography, magnetic resonance imaging, and ultrasonography are also useful for differentiating the soft tissue lesions. We report a 17-year-old girl with a small mass containing a calcified body in the anterior portion of the masseter muscle. The mass was resected surgically and evaluated histologically, confirming the diagnosis of phlebolith. We also discuss the differential diagnosis of a buccal soft tissue mass containing calcifications and suggest that the immunolocalization of CD31 at capillaries in the mass may help to diagnose as a phlebolith. PMID:22488560

  11. A Short-term Comparison Between Result of Palisade Cartilage Tympanoplasty and Temporalis Fascia Technique

    PubMed Central

    Shishegar, Mahmood; Faramarzi, Abolhasan; Taraghi, Ayeh

    2012-01-01

    Introduction: The use of cartilage as a grafting material has been advocated in cases where there is a high risk of graft failure, such as subtotal perforations, adhesive processes, and residual defects after primary tympanoplasties. The purpose of this study was to compare the graft acceptance rates and auditory outcomes of cartilage tympanoplasty operations using a palisade technique with those of primary tympanoplasty using temporalis fascia in a homogenous group of patients. Study Design: Prospective study. Materials and Methods: The study population included 54 patients who were operated on in two groups (palisade technique & temporalis fascia technique) with each group containing 27 patients. Patients with pure subtotal perforations (perforation of >50% of the whole tympanic membrane [TM] area), an intact ossicular chain, at least a one month dry period, and normal middle ear mucosa were included in the study. Grafts acceptance rates and pre- and post-operative audiograms were compared. The follow-up time was six months. Results: Graft acceptance was achieved in all patients (100%) in the palisade cartilage tympanoplasty group and in 25 patients (92.5%) in the temporalis fascia group. This difference was not statistically significant (P= 0.15). Comparison of the increases in mean speech reception threshold, air–bone gap, and pure-tone average scores between both techniques showed no significant changes. Conclusion: Our experience with the palisade cartilage technique demonstrates that subtotal or total perforation at high risk for graft failure can be treated efficiently, and that a durable and resistant reconstruction of the TM with reasonable auditory function can be achieved. PMID:24303394

  12. Muscle-spindle distribution in relation to the fibre-type composition of masseter in mammals.

    PubMed Central

    Rowlerson, A; Mascarello, F; Barker, D; Saed, H

    1988-01-01

    The various parts of the masseter muscle complex (pars superficialis, pars profunda, zygomaticomandibularis, maxillomandibularis) in the rat, guinea-pig, rabbit, cat and macaque monkey were examined to discover whether they showed any relationship between the distribution of muscle spindles and extrafusal fibre types. Intrafusal (spindle) and extrafusal fibre types in masseter were compared with those in limb muscles and were identified by a combination of standard histochemical methods and indirect immunoperoxidase staining with antibodies specific for the various isoforms of myosin characteristic of fibre types in mammalian muscle. In general, the fibre-type properties of intrafusal fibres in masseter resembled those in limb muscle spindles, but the extrafusal fibre-type composition was unlike that in most limb muscles. In the rat masseter, most of the spindles were clustered together in a few very restricted areas. Extensive fusion of the external capsules of adjacent spindles, resulting in the formation of giant spindles, was seen in the cat and monkey masseter; this was sometimes accompanied by the enclosure of extrafusal fibres within the fused spindles. Common to all species, but strongest of all in the rat, was a close association between the distributions of muscle spindles and extrafusal Type I (slow twitch) fibres within the masseter complex. Muscle spindles and Type I fibres were either absent or rarest in the superficial part of masseter, but were most common in the deep layer (pars profunda) or zygomaticomandibularis. The functional significance of these observations is discussed. Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:2978294

  13. Protective Effects of Clenbuterol against Dexamethasone-Induced Masseter Muscle Atrophy and Myosin Heavy Chain Transition

    PubMed Central

    Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Suita, Kenji; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

    2015-01-01

    Background Glucocorticoid has a direct catabolic effect on skeletal muscle, leading to muscle atrophy, but no effective pharmacotherapy is available. We reported that clenbuterol (CB) induced masseter muscle hypertrophy and slow-to-fast myosin heavy chain (MHC) isoform transition through direct muscle β2-adrenergic receptor stimulation. Thus, we hypothesized that CB would antagonize glucocorticoid (dexamethasone; DEX)-induced muscle atrophy and fast-to-slow MHC isoform transition. Methodology We examined the effect of CB on DEX-induced masseter muscle atrophy by measuring masseter muscle weight, fiber diameter, cross-sectional area, and myosin heavy chain (MHC) composition. To elucidate the mechanisms involved, we used immunoblotting to study the effects of CB on muscle hypertrophic signaling (insulin growth factor 1 (IGF1) expression, Akt/mammalian target of rapamycin (mTOR) pathway, and calcineurin pathway) and atrophic signaling (Akt/Forkhead box-O (FOXO) pathway and myostatin expression) in masseter muscle of rats treated with DEX and/or CB. Results and Conclusion Masseter muscle weight in the DEX-treated group was significantly lower than that in the Control group, as expected, but co-treatment with CB suppressed the DEX-induced masseter muscle atrophy, concomitantly with inhibition of fast-to-slow MHC isoforms transition. Activation of the Akt/mTOR pathway in masseter muscle of the DEX-treated group was significantly inhibited compared to that of the Control group, and CB suppressed this inhibition. DEX also suppressed expression of IGF1 (positive regulator of muscle growth), and CB attenuated this inhibition. Myostatin protein expression was unchanged. CB had no effect on activation of the Akt/FOXO pathway. These results indicate that CB antagonizes DEX-induced muscle atrophy and fast-to-slow MHC isoform transition via modulation of Akt/mTOR activity and IGF1 expression. CB might be a useful pharmacological agent for treatment of glucocorticoid

  14. Masseter segmentation using an improved watershed algorithm with unsupervised classification.

    PubMed

    Ng, H P; Ong, S H; Foong, K W C; Goh, P S; Nowinski, W L

    2008-02-01

    The watershed algorithm always produces a complete division of the image. However, it is susceptible to over-segmentation and sensitivity to false edges. In medical images this leads to unfavorable representations of the anatomy. We address these drawbacks by introducing automated thresholding and post-segmentation merging. The automated thresholding step is based on the histogram of the gradient magnitude map while post-segmentation merging is based on a criterion which measures the similarity in intensity values between two neighboring partitions. Our improved watershed algorithm is able to merge more than 90% of the initial partitions, which indicates that a large amount of over-segmentation has been reduced. To further improve the segmentation results, we make use of K-means clustering to provide an initial coarse segmentation of the highly textured image before the improved watershed algorithm is applied to it. When applied to the segmentation of the masseter from 60 magnetic resonance images of 10 subjects, the proposed algorithm achieved an overlap index (kappa) of 90.6%, and was able to merge 98% of the initial partitions on average. The segmentation results are comparable to those obtained using the gradient vector flow snake. PMID:17950265

  15. Cysticercosis of temporalis muscle: an unusual cause of temporal headaches. A case report.

    PubMed

    Sethi, Prahlad K; Sethi, Nitin K; Torgovnick, Josh; Arsura, Edward

    2007-10-01

    Cysticercosis is a common parasitic infection caused by encysted larvae of the helminth Taenia solium (pork tapeworm). The central nervous system (CNS) is the most important primary site of infection and the disease can present with solitary or multiple space occupying lesions. Less common presentations in the CNS include the racemose variety with macroscopic groups of cysticerci in the subarachnoid space giving the appearance of a cluster of grapes and basal or ventricular cysticercosis causing obstructive hydrocephalus. Involvement of other organs: skeletal muscle, eyes, myocardium and the lungs has also been reported. Cases of cysticercosis presenting as isolated muscle mass (pseudotumours) without involvement of the CNS have also been recently described in the literature. We present a case of a 43-year-old woman who complained of subacute onset of left temporal pain and headache. Magnetic resonance imaging (MRI) showed characteristic imaging findings suggestive of cysticercosis of the temporalis muscle. PMID:17955174

  16. Expression of CGRP in embryonic mouse masseter muscle.

    PubMed

    Azuma, Yuri; Miwa, Yoko; Sato, Iwao

    2016-07-01

    Neuropeptide calcitonin gene-related peptide (CGRP) is a mediator of inflammation and head pain that influences the functional vascular blood supply. The CGRP also regulate myoblast and acetylcholine receptors on neuromuscular junctions in development. However, little is known about its appearance and location during mouse masseter muscle (MM) development. We detected the mRNA abundance of CGRP, vascular genesis markers (Vascular endothelial growth factor A (VEGF-A), PECAM (CD31), lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1)) and embryonic and adult myosin heavy chain (MyHCs) (embryonic, IIa, IIb, and IIx) using real-time RT-PCR during development from the embryonic stage to after birth (E12.5, E14.5, E17.5, E18.5, P0, P1 and P5). We also endeavored to analyze the expression and localization of CGRP in situ hybridization in the developing mouse MM during development from the embryonic stage to after birth (E12.5, E14.5, E17.5, and P1). The antisense probe for CGRP was detected by in situ hybridization at E12.5, E14.5 E17.5 and then no longer detected after birth. The CGRP, CD31, embryonic MyHC abundance levels are highest at E17.5 (p<0.001) and they show a pattern similar to that of the other markers from E12.5 to P5. PCA analysis indicates a specific relation between CGRP and embryonic MyHC, CD31, and LYVE-1 in MM development. Cluster analyses identified the following distinct clusters for mRNA abundance in the MM: cluster 1, P5; cluster 2, E12.5, E14.5, E17.5, E18.5, P0, and P1. The positive correlation between CGRP and embryonic MyHC (Pearson's r>0.65; p<0.01) was analyzed. These data suggested that CGRP may have an influence on embryonic MyHC during mouse MM development. CGRP also affects the angiogenesis markers at embryonic stages. PMID:27136747

  17. Ultrasonography Guided Excision of Isolated Cysticercosis of the Temporalis Muscle Causing Intractable Headache: A Rare Case Report.

    PubMed

    Kumar, Vivek; Bhavana, Kranti; Kumar, Prem; Kumar, Subhash

    2016-09-01

    Cysticercosis cellulosae is a systemic parasitic infection caused by the larval stage of pork tapeworm, Taenia solium which involve humans as either a definitive or secondary hosts. The central nervous system is the most important primary site of involvement. Cases of cysticercosis presenting as an isolated muscle mass is an extremely rare entity and demands documentation. We report an extremely unusual case of isolated cysticercosis of the temporalis muscle causing intractable headache which presented a diagnostic challenge. The condition was surgically treated by ultrasonography guided excision of the cysticercosis swelling in the temporalis muscle. We also emphasize on the role of proper imaging modalities in the diagnosis and treatment of such unique cases. PMID:27508147

  18. Myosin heavy chain expression in rabbit masseter muscle during postnatal development.

    PubMed Central

    Bredman, J J; Weijs, W A; Korfage, H A; Brugman, P; Moorman, A F

    1992-01-01

    The expression of isoforms of myosin heavy chain (MHC) during postnatal development was studied in the masseter muscle of the rabbit. Evidence is presented that in addition to adult fast and slow myosin, the rabbit masseter contains neonatal and 'cardiac' alpha-MHC. During postnatal growth myosin transitions take place from neonatal and fast (IIA, IIA/IIB--referring to a fibre containing both IIA and IIB MHCs) MHC to adult 'cardiac' alpha-MHC and I/alpha-MHC. Since there is a temporary population of fibres containing IIA/alpha-MHC during the first 4 wk of development with a peak in the 3rd to 4th wk, the transition from IIA-MHC to alpha-MHC may occur in these IIA/alpha-MHC-containing fibres. The appearance of 'cardiac' alpha-MHC coincides with the timing of weaning, suggesting that the changes in MHC content, that probably result in a transition to a lower speed of contraction, have functional significance related to weaning. The finding of neonatal MHC in adult rabbits indicates that the masseter develops at a rate and in a way that is distinct from most other skeletal muscles. A spatiotemporal variation in expression of myosin isozymes within the masseter was observed, with many fibres containing more than one myosin type, indicating developmentally regulated spatial differences in function. Images Fig. 2 Fig. 3 Fig. 4 Fig. 7 PMID:1387129

  19. Fetal Tendinous Connection Between the Tensor Tympani and Tensor Veli Palatini Muscles: A Single Digastric Muscle Acting for Morphogenesis of the Cranial Base.

    PubMed

    Rodríguez-Vázquez, José Francisco; Sakiyama, Koji; Abe, Hiroshi; Amano, Osamu; Murakami, Gen

    2016-04-01

    Some researchers contend that in adults the tensor tympani muscle (TT) connects with the tensor veli palatini muscle (TVP) by an intermediate tendon, in disagreement with the other researchers. To resolve this controversy, we examined serial sections of 50 human embryos and fetuses at 6-17 weeks of development. At 6 weeks, in the first pharyngeal arch, a mesenchymal connection was found first to divide a single anlage into the TT and TVP. At and after 7 weeks, the TT was connected continuously with the TVP by a definite tendinous tissue mediolaterally crossing the pharyngotympanic tube. At 11 weeks another fascia was visible covering the cranial and lateral sides of the tube. This "gonial fascia" had two thickened borders: the superior one corresponded to a part of the connecting tendon between the TT and TVP; the inferior one was a fibrous band ending at the os goniale near the lateral end of the TVP. In association with the gonial fascia, the fetal TT and TVP seemed to provide a functional complex. The TT-TVP complex might first help elevate the palatal shelves in association with the developing tongue. Next, the tubal passage, maintained by contraction of the muscle complex, seems to facilitate the removal of loose mesenchymal tissues from the tympanic cavity. Third, the muscle complex most likely determined the final morphology of the pterygoid process. Consequently, despite the controversial morphologies in adults, the TT and TVP seemed to make a single digastric muscle acting for the morphogenesis of the cranial base. Anat Rec, 299:474-483, 2016. © 2016 Wiley Periodicals, Inc. PMID:26744237

  20. Small vertical changes in jaw relation affect motor unit recruitment in the masseter.

    PubMed

    Terebesi, S; Giannakopoulos, N N; Brüstle, F; Hellmann, D; Türp, J C; Schindler, H J

    2016-04-01

    Strategies for recruitment of masseter muscle motor units (MUs), provoked by constant bite force, for different vertical jaw relations have not previously been investigated. The objective of this study was to analyse the effect of small changes in vertical jaw relation on MU recruitment behaviour in different regions of the masseter during feedback-controlled submaximum biting tasks. Twenty healthy subjects (mean age: 24·6 ± 2·4 years) were involved in the investigation. Intra-muscular electromyographic (EMG) activity of the right masseter was recorded in different regions of the muscle. MUs were identified by the use of decomposition software, and root-mean-square (RMS) values were calculated for each experimental condition. Six hundred and eleven decomposed MUs with significantly (P < 0·001) different jaw relation-specific recruitment behaviour were organised into localised MU task groups. MUs with different task specificity in seven examined tasks were observed. The RMS EMG values obtained from the different recording sites were also significantly (P < 0·01) different between tasks. Overall MU recruitment was significantly (P < 0·05) greater in the deep masseter than in the superficial muscle. The number of recruited MUs and the RMS EMG values decreased significantly (P < 0·01) with increasing jaw separation. This investigation revealed differential MU recruitment behaviour in discrete subvolumes of the masseter in response to small changes in vertical jaw relations. These fine-motor skills might be responsible for its excellent functional adaptability and might also explain the successful management of temporomandibular disorder patients by somatic intervention, in particular by the use of oral splints. PMID:26707515

  1. The effects of changes in response-independent pay upon human masseter EMG. M.A. Thesis

    NASA Technical Reports Server (NTRS)

    Proni, T. J.

    1973-01-01

    Electromyographic activity of the masseter muscle was recorded in five human subjects who were presented with systematically varied rates of non-contingent pay. Rates of pay were varied between sessions in either a descending or an ascending series. The number of masseter contractions was found to be greater during the descending series than during the ascending series, especially when a descending series of pay changes followed an ascending series. Verbal physical displays of anger and aggression were noted during descending series. These data indicated a possible relation between masseter contractions and aggression.

  2. Ultrastructural features of masseter muscle exhibiting altered occlusal relationship - a study in a rodent model

    SciTech Connect

    Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Pinheiro, Antonio L. B.; Santos, Jean N.; Baptista, Abrahao F.; Aguiar, Marcio C.

    2010-05-31

    The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

  3. Analysis of masseter and temporal muscles during surgical extraction of impacted third molars.

    PubMed

    Moraes, Michelle B; Naclerio-Homem, Maria G; Nascimento, Rodrigo D; Oliveira Amorim, Jose Benedito; Raldi, Fernando V

    2015-01-01

    With the aim of contributing to the discussion on stomatognathic system dysfunction after surgical procedures, this study compared the electromyographic activity of the superficial masseter and temporal masticatory muscles before, during, and after impacted mandibular third molar extractions. Muscular activity was recorded presurgery, transsurgery, immediately postoperatively, and on postoperative days 7, 15, and 30. Twenty patients requiring extraction of impacted mandibular third molars were selected and evaluated. In 20 patients who underwent mandibular third molar extractions, electromyography showed no alterations in muscle tone, and no statistically significant differences were observed in the left and right temporal and masseter muscles at any of the experimental periods at either mandibular rest or isometric contraction position. However, the degree of mouth opening increased 11.76% from pretreatment to 30 days after surgery. These results may reflect the shorter, careful extraction procedure performed by the surgeon. PMID:26325653

  4. Regional changes in the masseter muscle of rats after reduction of blood supply.

    PubMed

    Proff, Peter; Weingärtner, Jens; Fanghänel, Jochen; Gredes, Marzena; Mai, Ronald; Gedrange, Tomas

    2007-01-01

    The masticatory musculature is an integral functional part of the stomatognathic system and influences craniofacial morphogenesis and morphology. This animal study aimed to investigate the morphological consequences of restricted regional blood supply to the m. masseter. A total of 20 adult male Wistar rats (Rattus norvegicus Berkenhout) were divided into an experimental group and a control group comprised of 10 animals respectively and kept under standardized conditions. The experimental group underwent a dextrolateral complete surgical ligation of the a. carotis communis and, after 5 weeks, specimens were taken from the masseters. The muscle samples were analyzed immunohistochemically for fiber distribution and capillary density. Analysis revealed a discrete increase in the proportion of type I fibers with a significant increase of capillary number per area. Although no agreement exists on the alterations occurring in chronically ischemic muscles, it may be assumed that chronic ischemia evokes histomorphological adaptation processes similar to endurance training effects. PMID:17319610

  5. Age-dependent changes in cat masseter nerve: an electrophysiological and morphological study.

    PubMed

    Chase, M H; Engelhardt, J K; Adinolfi, A M; Chirwa, S S

    1992-07-24

    The present study was undertaken to determine the manner in which aging affects the function and structure of the masseter nerve in old cats. Electrophysiological data demonstrated a significant decrease in the conduction velocity of the action potential in old cats compared with that observed in adult cats. Light microscopic analyses revealed an age-dependent decrease in axon diameter. Electron microscopic observations of the masseter nerve in the aged cats revealed a disruption of the myelin sheaths and a pronounced increase in collagen fibers in the endoneurium and perineurium. These morphological changes are discussed and then related to the decrease in conduction velocity which was observed in the electrophysiological portion of this study. PMID:1521161

  6. Ultrastructural features of masseter muscle exhibiting altered occlusal relationship—a study in a rodent model

    NASA Astrophysics Data System (ADS)

    Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Baptista, Abrahão F.; Pinheiro, Antonio L. B.; Aguiar, Marcio C.; Santos, Jean N.

    2010-05-01

    The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

  7. Intracortical modulation of cortical-bulbar responses for the masseter muscle

    PubMed Central

    Ortu, Enzo; Deriu, Franca; Suppa, Antonio; Giaconi, Elena; Tolu, Eusebio; Rothwell, John C

    2008-01-01

    Short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were evaluated in the masseter muscles of 12 subjects and the cortical silent period (SP) in nine subjects. Motor evoked potentials (MEPs) were recorded from contralateral (cMM) and ipsilateral (iMM) masseters, activated at 10% of maximal voluntary contraction (MVC). Interstimulus intervals (ISIs) were 2 and 3 ms for SICI, 10 and 15 ms for ICF. TMS of the left masseteric cortex induced MEPs that were larger in the cMM than the iMM; stimulation of right masseteric cortex produced a similar asymmetry in response amplitude. SICI was only observed using a CS intensity of 70% AMT and was equal in both cMM and iMM. SICI was stronger at higher TS intensities, was abolished by muscle activation greater than 10% MVC, and was unaffected by coil orientation changes. Control experiments confirmed that SICI was not contaminated by any inhibitory peripheral reflexes. However, ICF could not be obtained because it was masked by bilateral reflex depression of masseter EMG caused by auditory input from the coil discharge. The SP was bilateral and symmetric; its duration ranged from 35 to 70 ms depending on TS intensity and coil orientation. We conclude that SICI is present in the cortical representation of masseter muscles. The similarity of SICI in cMM and iMM suggests either that a single pool of inhibitory interneurons controls ipsi- and contralateral corticotrigeminal projections or that inhibition is directed to bilaterally projecting corticotrigeminal fibres. Finally, the corticotrigeminal projection seems to be weakly influenced by inhibitory interneurons mediating the cortical SP. PMID:18499727

  8. Electromyographic analysis of masseter muscle in newborns during suction in breast, bottle or cup feeding

    PubMed Central

    2014-01-01

    Background When breastfeeding is difficult or impossible during the neonatal period, an analysis of muscle activity can help determine the best method for substituting it to promote the child’s development. The aim of this study was to analyze the electrical activity of the masseter muscle using surface electromyography during suction in term newborns by comparing breastfeeding, bottle and cup feeding. Methods An observational, cross-sectional analytical study was carried out on healthy, clinically stable term infants, assigned to receive either breast, or bottle or cup feeding. Setting was a Baby Friendly accredited hospital. Muscle activity was analyzed when each infant showed interest in sucking using surface electromyography. Root mean square averages (RMS) recorded in microvolts were transformed into percentages (normalization) of the reference value. The three groups were compared by ANOVA; the “stepwise” method of the multiple linear regression analysis tested the model which best defined the activity of the masseter muscle in the sample at a significance level of 5%. Results Participants were 81 full term newborns (27 per group), from 2 to 28 days of life. RMS values were lower for bottle (mean 44.2%, SD 14.1) than breast feeding (mean 58.3%, SD 12.7) (P = 0.003, ANOVA); cup feeding (52.5%, SD 18.2%) was not significantly different (P > 0.05). For every gram of weight increase, RMS increased by 0.010 units. Conclusions Masseter activity was significantly higher in breastfed newborns than in bottle-fed newborns, who presented the lowest RMS values. Levels of masseter activity during cup-feeding were between those of breast and bottle feeding, and did not significantly differ from either group. This study in healthy full term neonates endorses cup rather than bottle feeding as a temporary substitute for breastfeeding. PMID:24885762

  9. [Lengthening temporalis myoplasty: A new approach to facial rehabilitation with the "mirror-effect" method].

    PubMed

    Blanchin, T; Martin, F; Labbe, D

    2013-12-01

    Peripheral facial paralysis often reveals two conditions that are hard to control: labial occlusion and palpebral closure. Today, there are efforts to go beyond the sole use of muscle stimulation techniques, and attention is being given to cerebral plasticity stimulation? This implies using the facial nerves' efferent pathway as the afferent pathway in rehabilitation. This technique could further help limit the two recalcitrant problems, above. We matched two groups of patients who underwent surgery for peripheral facial paralysis by lengthening the temporalis myoplasty (LTM). LTM is one of the best ways to examine cerebral plasticity. The trigeminal nerve is a mixed nerve and is both motor and sensory. After a LTM, patients have to use the trigeminal nerve differently, as it now has a direct role in generating the smile. The LTM approach, using the efferent pathway, therefore, creates a challenge for the brain. The two groups followed separate therapies called "classical" and "mirror-effect". The "mirror-effect" method gave a more precise orientation of the patient's cerebral plasticity than did the classical rehabilitation. The method develops two axes: voluntary movements patients need to control their temporal smile; and spontaneous movements needed for facial expressions. Work on voluntary movements is done before a "digital mirror", using an identical doubled hemiface, providing the patient with a fake copy of his face and, thus, a 7 "mirror-effect". The spontaneous movements work is based on what we call the "Therapy of Motor Emotions". The method presented here is used to treat facial paralysis (Bell's Palsies type), whether requiring surgery or not. Importantly, the facial nerve, like the trigeminal nerve above, is also a mixed nerve and is stimulated through the efferent pathway in the same manner. PMID:23598073

  10. Effect of hypnosis on masseter EMG recorded during the 'resting' and a slightly open jaw posture.

    PubMed

    Al-Enaizan, N; Davey, K J; Lyons, M F; Cadden, S W

    2015-11-01

    The aim of this experimental study was to determine whether minimal levels of electromyographic activity in the masseter muscle are altered when individuals are in a verified hypnotic state. Experiments were performed on 17 volunteer subjects (8 male, 9 female) all of whom gave informed consent. The subjects were dentate and had no symptoms of pain or masticatory dysfunction. Surface electromyograms (EMGs) were made from the masseter muscles and quantified by integration following full-wave rectification and averaging. The EMGs were obtained (i) with the mandible in 'resting' posture; (ii) with the mandible voluntarily lowered (but with the lips closed); (iii) during maximum voluntary clenching (MVC). The first two recordings were made before, during and after the subjects were in a hypnotic state. Susceptibility to hypnosis was assessed with Spiegel's eye-roll test, and the existence of the hypnotic state was verified by changes in ventilatory pattern. On average, EMG levels expressed as percentages of MVC were less: (i) when the jaw was deliberately lowered as opposed to being in the postural position: (ii) during hypnosis compared with during the pre- and post-hypnotic periods. However, analysis of variance followed by post hoc tests with multiple comparison corrections (Bonferroni) revealed that only the differences between the level during hypnosis and those before and after hypnosis were statistically significant (P < 0·05). As the level of masseter EMG when the mandible was in 'resting' posture was reduced by hypnosis, it appears that part of that EMG is of biological origin. PMID:26059538

  11. Demographic Effects of Habitat Restoration for the Grey-Crowned Babbler Pomatostomus temporalis, in Victoria, Australia

    PubMed Central

    Vesk, Peter A.; Robinson, Doug; van der Ree, Rodney; Wilson, Caroline M.; Saywell, Shirley; McCarthy, Michael A.

    2015-01-01

    Background Considerable resources are spent on habitat restoration across the globe to counter the impacts of habitat loss and degradation on wildlife populations. But, because of time and resourcing constraints on many conservation programs, the effectiveness of these habitat restoration programs in achieving their long-term goals of improving the population viability of particular wildlife species is rarely assessed and many restoration programs cannot demonstrate their effectiveness. Without such demonstration, and in particular demonstrating the causal relationships between habitat restoration actions and demographic responses of the target species, investments in restoration to achieve population outcomes are of uncertain value. Approach Here, we describe an approach that builds on population data collected for a threatened Australian bird – the Grey-crowned Babbler Pomatostomus temporalis - to evaluate how effectively targeted habitat restoration work improves its viability. We built upon an extensive historical survey by conducting surveys 13 years later at 117 sites stratified by presence/absence of restoration works and by detection or not of birds in the first survey. Our performance metric was the number of individuals in a social group, which is both a measure of local abundance and directly related to breeding success. We employed an occupancy model to estimate the response of Grey-crowned Babbler social group size to the effects of time, restoration works, local habitat as measured by the density of large trees, and distance to the nearest other known group of babblers. Results and implications Babbler group size decreased over the survey period at sites without restoration works, but restoration works were effective in stemming declines where they were done. Restoration was responsible for a difference of about one bird per group of 3-5 individuals; this is an important effect on the reproductive success of the social group. Effectiveness of

  12. Influence of experimental oesophageal acidification on masseter muscle activity, cervicofacial behaviour and autonomic nervous activity in wakefulness.

    PubMed

    Ohmure, H; Sakoguchi, Y; Nagayama, K; Numata, M; Tsubouchi, H; Miyawaki, S

    2014-06-01

    Recent studies have been revealing the relationship between the stomatognathic system and the gastrointestinal tract. However, the effect of oesophageal acid stimulation on masticatory muscle activity during wakefulness has not been fully elucidated. To examine whether intra-oesophageal acidification induces masticatory muscle activity, a randomised trial was conducted investigating the effect of oesophageal acid infusion on masseter muscle activity, autonomic nervous system (ANS) activity and subjective symptoms. Polygraphic monitoring consisting of electromyography of the masseter muscle, electrocardiography and audio-video recording was performed in 15 healthy adult men, using three different 30-min interventions: (i) no infusion, (ii) intra-oesophageal saline infusion and (iii) intra-oesophageal infusion of acidic solution (0·1 N HCl; pH 1·2). This study was registered with the UMIN Clinical Trials Registry, UMIN000005350. Oesophageal acid stimulation significantly increased masseter muscle activity during wakefulness, especially when no behaviour was performed in the oro-facial region. Chest discomfort, including heartburn, also increased significantly after oesophageal acid stimulation; however, no significant correlation was observed between increased subjective symptoms and masseter muscle activity. Oesophageal acid infusion also altered ANS activity; a significant correlation was observed between masticatory muscle changes and parasympathetic nervous system activity. These findings suggest that oesophageal-derived ANS modulation induces masseter muscle activity, irrespective of the presence or absence of subjective gastrointestinal symptoms. PMID:24655114

  13. Investigation of an unusual, high-frequency jaw tremor with coherence analysis.

    PubMed

    Sowman, Paul F; Thompson, Philip D; Miles, Timothy S

    2008-02-15

    Normal physiological tremor of the jaw has a frequency of 6 to 8 Hz. A patient is described with jaw tremor at frequencies of 12 Hz during jaw movement and 15 Hz when the jaw was relaxed. The 15 Hz tremor was driven by synchronous, bilateral bursts of activity in the temporalis and masseter muscles, which alternated with digastric bursts. Coherence analysis indicated the tremor was highly correlated with both opening and closing muscle activity, and that the opening and closing muscles were about 180 degrees out of phase. The existence of two tremors with different, nonphysiological peak frequencies and the influence of attention, relaxation, and movement in switching from one tremor frequency to the other, suggest that more than one generator may be operating. PMID:18067185

  14. Density of muscle spindles in the jaw muscles of the Japanese flying squirrel and the guinea pig.

    PubMed

    Odagiri, N; Kubota, K; Shibanai, S

    1993-06-01

    The number of muscle spindles and their distribution pattern in the jaw muscles were examined in serial sections of the heads of the Japanese flying squirrel and the guinea pig, and were compared with each other. The Japanese flying squirrel had 127 to 177 spindles, the length of which ranged from 140 microns to 1400 microns; 74 to 99 in the masseter, 39 to 47 in the temporalis, 11 to 28 in the zygomaticomandibularis, zero to one in the maxillomandibularis and two to three in the medial pterygoid muscles. The guinea pig had 322 to 346 spindles, the length of which ranged from 140 microns to 2800 microns; 116 to 125 in the masseter, 15 to 16 in the temporalis, 98 to 107 in the zygomaticomandibularis, 89 to 94 in the maxillomandibularis, and three to five in the medial pterygoid muscles. The lateral pterygoid, mylohyoid and anterior digastric muscles were devoid of spindles, as was the case in the other rodent species examined. PMID:8338226

  15. Myositis ossificans of the masseter muscle: A rare location. Report of a case and review of literature

    PubMed Central

    Martos-Fernández, Míriam; Alberola-Ferranti, Margarita; Romanini-Montecino, Carolina; Saez-Barba, Manel; Bescós-Atín, Coro

    2016-01-01

    Background Myositis Ossificans is a rare heterotopic bone formation within a muscle being the masticatory muscles exceptionally involved. In most cases there is a previous trauma, bearing in mind that there may be many other etiologies. CT scan and panoramic radiographs along with histological findings are essential diagnostic aids. Case Desciption We report a rare case of MO of masseter muscle in 49 years-old woman after repetitive wisdom tooth infection with the discussion of clinical, radiological and histological features. Clinical Implications MO is a rare disease of masticatory muscles being the masseter the most frequently affected. Wide surgical excision with free margins is the treatment of choice although close postoperative monitoring it’s essential to avoid relapses. Key words:Myositis ossificans, myositis ossificans traumatica, masticatory muscles, masseter muscle, trauma. PMID:27034763

  16. Origin of sound-evoked EMG responses in human masseter muscles

    PubMed Central

    Deriu, Franca; Ortu, Enzo; Capobianco, Saverio; Giaconi, Elena; Melis, Francesco; Aiello, Elena; Rothwell, John C; Tolu, Eusebio

    2007-01-01

    Sound is a natural stimulus for both cochlear and saccular receptors. At high intensities it evokes in active masseter muscles of healthy subjects two overlapping reflexes: p11/n15 and p16/n21 waves, whose origin has not yet been demonstrated. Our purpose was to test which receptor in the inner ear is responsible for these reflexes. We compared masseter EMG responses induced in normal subjects (n = 9) by loud clicks (70–100 dB normal hearing level (NHL), 0.1 ms, 3 Hz) to those evoked in subjects with a selective lesion of the cochlea (n = 5), of the vestibule (n = 1) or with mixed cochlear-vestibular failure (n = 5). In controls, 100 dB clicks induced bilaterally, in the unrectified mean EMG (unrEMG), a clear p11 wave followed by a less clear n15 wave and a subsequent n21 wave. Lowering the intensity to 70 dB clicks abolished the p11/n15 wave, while a p16 wave appeared. Rectified mean EMG (rectEMG) showed, at all intensities, an inhibitory deflection corresponding to the p16/n21 wave in the unrEMG. Compared to controls, all deaf subjects had a normal p11 wave, together with more prominent n15 wave; however, the p16/n21 waves, and their corresponding inhibition in the rectEMG, were absent. The vestibular patient had bilaterally clear p11 waves only when 100 dB clicks were delivered bilaterally or to the unaffected ear. Stimulation of the affected ear induced only p16/n21 waves. Data from mixed patients were consistent with those of deaf and vestibular patients. We conclude that click-induced masseter p11/n15 waves are vestibular dependent, while p16/n21 waves depend on cochlear integrity. PMID:17234698

  17. Metabolic Changes in Masseter Muscle of Rats Submitted to Acute Stress Associated with Exodontia

    PubMed Central

    Iyomasa, Mamie Mizusaki; Fernandes, Fernanda Silva; Iyomasa, Daniela Mizusaki; Pereira, Yamba Carla Lara; Fernández, Rodrigo Alberto Restrepo; Calzzani, Ricardo Alexandre; Nascimento, Glauce Crivelaro; Leite-Panissi, Christie Ramos Andrade; Issa, João Paulo Mardegan

    2015-01-01

    Clinical evidence has shown that stress may be associated with alterations in masticatory muscle functions. Morphological changes in masticatory muscles induced by occlusal alterations and associated with emotional stress are still lacking in the literature. The objective of this study was to evaluate the influence of acute stress on metabolic activity and oxidative stress of masseter muscles of rats subjected to occlusal modification through morphological and histochemical analyses. In this study, adult Wistar rats were divided into 4 groups: a group with extraction and acute stress (E+A); group with extraction and without stress (E+C); group without extraction and with acute stress (NO+A); and control group without both extraction and stress (NO+C). Masseter muscles were analyzed by Succinate Dehydrogenase (SDH), Nicotinamide Adenine Dinucleotide Diaphorase (NADH) and Reactive Oxygen Species (ROS) techniques. Statistical analyses and two-way ANOVA were applied, followed by Tukey-Kramer tests. In the SDH test, the E+C, E+A and NO+A groups showed a decrease in high desidrogenase activities fibers (P < 0.05), compared to the NO+C group. In the NADH test, there was no difference among the different groups. In the ROS test, in contrast, E+A, E+C and NO+A groups showed a decrease in ROS expression, compared to NO+C groups (P < 0.05). Modified dental occlusion and acute stress - which are important and prevalent problems that affect the general population - are important etiologic factors in metabolic plasticity and ROS levels of masseter muscles. PMID:26053038

  18. Time Course Analysis of the Effects of Botulinum Neurotoxin Type A on Pain and Vasomotor Responses Evoked by Glutamate Injection into Human Temporalis Muscles

    PubMed Central

    Bittencourt da Silva, Larissa; Kulas, Dolarose; Karshenas, Ali; Cairns, Brian E.; Bach, Flemming W.; Arendt-Nielsen, Lars; Gazerani, Parisa

    2014-01-01

    The effect of botulinum neurotoxin type A (BoNTA) on glutamate-evoked temporalis muscle pain and vasomotor responses was investigated in healthy men and women over a 60 day time course. Subjects participated in a pre-BoNTA session where their responses to injection of glutamate (1 M, 0.2 mL) and saline (0.2 mL) into the temporalis muscles were assessed. On Day 1, BoNTA (5 U) was injected into one temporalis muscle and saline into the contralateral temporalis muscle, in a randomized order. Subjects then received intramuscular injections of glutamate (1 M, 0.2 mL) into the left and right temporalis muscles at 3 h and subsequently 7, 30 and 60 days post-injection of BoNTA. Pain intensity, pain area, and neurogenic inflammation (skin temperature and skin blood perfusion) were recorded. Prior to BoNTA treatment, glutamate evoked significantly greater pain and vasomotor reactions (P < 0.001) than saline. BoNTA significantly reduced glutamate-evoked pain intensity (P < 0.05), pain area (P < 0.01), skin blood perfusion (P < 0.05), and skin temperature (P < 0.001). The inhibitory effect of BoNTA was present at 3 h after injection, peaked after 7 days and returned to baseline by 60 days. Findings from the present study demonstrated a rapid action of BoNTA on glutamate-evoked pain and neurogenic inflammation, which is in line with animal studies. PMID:24517906

  19. Masseter muscle tension, chewing ability, and selected parameters of physical fitness in elderly care home residents in Lodz, Poland

    PubMed Central

    Gaszynska, Ewelina; Godala, Malgorzata; Szatko, Franciszek; Gaszynski, Tomasz

    2014-01-01

    Background Maintaining good physical fitness and oral function in old age is an important element of good quality of life. Disability-related impairment of oral function contributes to a deterioration of the diet of older people and to the reduction of their social activity. Objectives Investigate the association between masseter muscle tension, dental status, and physical fitness parameters. Materials and methods Two hundred fifty-nine elderly care home residents (97 men, 162 women; mean age, 75.3±8.9 years) were involved in this cross-sectional study. Their chewing ability was evaluated by masseter muscle tension palpation, differences of masseter muscle thickness, self-reported chewing ability, number of present and functional teeth, and number of posterior tooth pairs. Masseter muscle thickness was measured by ultrasonography. To assess physical fitness, hand grip strength and the timed up-and-go test were performed. Nutritional status was assessed using body mass index and body cell mass index (BCMI), calculated on the basis of electrical bioimpedance measurements. Medical records were used to collect information on systemic diseases and the number of prescribed medications. Subjects were also evaluated for their ability to perform ten activities of daily living. Results Ninety-seven percent of the subjects suffered from systemic diseases. The three most prevalent illnesses were cardiac/circulatory 64.5%, musculoskeletal 37.3%, and endocrine/metabolic/nutritional 29.3%. Of the participants, 1.5% were underweight and more than one third (34.4%) were overweight. Malnutrition (BCMI below normal) was found in almost half (45.2%) of the subjects. Only 5.8% had a sufficient number of functional natural teeth. Statistically significant correlations were found between palpation of masseter muscle tension and perceived chewing ability, number of present teeth, number of functional teeth, number of posterior tooth pairs, timed up-and-go, hand grip strength, body mass

  20. Temporalis Muscle Transfer for the Treatment of Lagophthalmos in Patients With Leprosy: Refinement in Surgical Techniques to Prevent Postoperative Ptosis.

    PubMed

    Ahn, Sung Yul; Park, Hyang Joon; Kim, Jong Pill; Park, Tae Hwan

    2016-01-01

    Facial paralysis resulting from leprosy has a serious impact on the entire face especially in the areas innervated by the facial nerves. In particular, lagophthalmos in patients with leprosy causes exposure keratitis, corneal, and conjunctival dryness, which can progress to blindness and disfigurement. Recently, we conducted 4 different temporalis muscle transfer (TMT) methods over the last 4 years to reduce ptosis. The methods used included Brown-McDowell, McCord-Codner, modified Gillies-Anderson, and modified Gillies. Seventy-five TMT operations in 60 patients were performed between 2011 and 2014. The mean age was 70.1. Fifteen patients had bilateral TMT procedures. As a result, ptosis appeared in 14(18.7%) of 75 TMT procedures for 4 years. To prevent or correct this complication, the following 4 technical refinements have simplified the surgery and yield better surgical outcomes. First, an increase in the length of the temporalis muscle flap to approximately 8 cm with a parallel course to the lateral canthus will reduce oblique pull. Second, the width of the fascia sling in the upper eyelid is narrowed (3-4 mm) to reduce weight on the eyelid. Third, the fascia sling in the upper lid should not be located along the full length of the upper lid but terminate 3.5 cm medial to lateral canthal tendon and in other words, should not be tied at the medial canthal tendon to reduce tension and weight. Lastly, the fascia sling in the eyelid should be located shallow (probably in subdermal layer) and as near as possible to the lid margin to prevent any functional disturbance in levator aponeurosis. PMID:26674897

  1. Chronic sleep deprivation alters the myosin heavy chain isoforms in the masseter muscle in rats.

    PubMed

    Cao, Ruihua; Huang, Fei; Wang, Peihuan; Chen, Chen; Zhu, Guoxiong; Chen, Lei; Wu, Gaoyi

    2015-05-01

    To investigate the changes in myosin heavy chain (MyHC) isoforms of rat masseter muscle fibres caused by chronic sleep deprivation and a possible link with the pathogenesis of disorders of the temporomandibular joint (TMJ). A total of 180 male rats were randomly divided into three groups (n=60 in each): cage controls, large platform controls, and chronic sleep deprivation group. Each group was further divided into three subgroups with different observation periods (7, 14, and 21 days). We investigated he expression of MyHC isoforms in masseter muscle fibres by real-time quantitative polymerase chain reaction (PCR), Western blotting, and immunohistochemical staining. In rats with chronic sleep deprivation there was increased MyHC-I expression in layers of both shallow and deep muscles at 7 and 21 days compared with the control groups, whereas sleep deprivation was associated with significantly decreased MyHC-II expression. At 21 days, there were no differences in MyHC-I or MyHC-II expression between the groups and there were no differences between the two control groups at any time point. These findings suggest that chronic sleep deprivation alters the expression of MyHC isoforms, which may contribute to the pathogenesis of disorders of the TMJ. PMID:25804396

  2. Extended effect after a single dose of type A botulinum toxin for asymmetric masseter muscle hypertrophy

    PubMed Central

    Bhattacharjee, Kasturi; Singh, Manpreet; Bhattacharjee, Harsha

    2015-01-01

    Facial asymmetry can either be physiological or pathological and is a common cosmetic concern. A 35-year-old Indian male presented with broad appearing lower face and prominent left jaw since adolescence. Parotid enlargement and other local disorders were ruled out. Ultrasonographic thickness of right masseter muscle was 13 mm while that of left was 14.9 mm, in unclenched state. Type-A botulinum toxin (T-ABT) was injected, evenly at five points, in both muscles within the “safe zone”. Using a 29 gauge needle, 15 and 25 international units were delivered to right and left masseters, respectively. Six months post — injection, a reduction of 2.9 mm and 4.4 mm was observed along with a reduced external facial asymmetry. At 24 months, patient maintains a satisfactory facial contour with no significant early or late post-injection complications. Intra-massteric injection of T-ABT can be used effectively as a primary or adjunct procedure for holistic oculo-facial sculpting. PMID:26424987

  3. Muscle hardness characteristics of the masseter muscle after repetitive muscle activation: comparison to the biceps brachii muscle.

    PubMed

    Kashima, Koji; Higashinaka, Shuichi; Watanabe, Naoshi; Maeda, Sho; Shiba, Ryosuke

    2004-10-01

    The purpose of this study was to compare hardness characteristics of the masseter muscle to those of the biceps brachii muscle during repetitive muscle movements. Seventeen asymptomatic female subjects participated in this study. Each subject, on separate days, undertook a 5-minute unilateral chewing gum task on the right side and a 5-minute flexion-extension exercise on the right hand with a 2kg dumbbell. Using a handheld hardness meter, muscle hardness was measured in the right masseter and in the biceps brachii muscle at eight time points (before the task, immediately after the task, and at 1, 3, 5, 10, 30, and 60 minutes after the task), and the data obtained before and after the task on each muscle were compared. Comparisons of the normalized data were also performed between the two muscles at each time point. As a result, a significant increase in muscle hardness was seen at 1 minute after the task in the biceps brachii muscle (p=0.0093). In contrast, the masseter muscle showed a tendency to lower hardness, with the lowest point of hardness occurring at 10 minutes after the task (p = 0.0160). Between the two muscles, there was a difference in the normalized data immediately after the task, and at 1, 5, and 10 minutes after the task (0.01 masseter muscle completely differed from those of the biceps brachii muscle after repetitive muscle activation. PMID:15532311

  4. Argus II retinal prosthesis implantation with scleral flap and autogenous temporalis fascia as alternative patch graft material: a 4-year follow-up

    PubMed Central

    Matet, Alexandre; Amar, Nawel; Mohand-Said, Saddek; Sahel, José-Alain; Barale, Pierre-Olivier

    2016-01-01

    Introduction The Argus II retinal prosthesis is composed of an epiretinal electrode array positioned over the macula and connected to an extrascleral electronics case via a silicone cable, running through a sclerotomy. During implantation, the manufacturer recommends to cover the sclerotomy site with a patch of processed human pericardium to prevent postoperative hypotony and conjunctival erosion by the underlying electronics case. Due to biomedical regulations prohibiting the use of this material in France, we developed an alternative technique combining a scleral flap protecting the sclerotomy and an autogenous graft of superior temporalis fascia overlying the electronics case. Methods The purpose of this study is to describe the 4-year outcomes of this modified procedure in three subjects who underwent Argus II Retinal Prosthesis System implantation. Clinical data consisting of intraocular pressure measurements and tolerance in terms of conjunctival erosion or inflammation were retrospectively assessed over a 4-year postoperative follow-up. Results None of the three patients implanted with the modified technique developed ocular hypotony over 4 years. A normal, transient conjunctival inflammation occurred during the first postoperative month but conjunctival erosion was not observed in any of the three patients over 4 years. Four years after implantation, the autogenous temporalis fascia graft remained well tolerated and the retinal prosthesis was functional in all three patients. Conclusion The combination of an autograft of superficial temporalis fascia and a scleral flap efficiently prevented leakage through the sclerotomy site, ocular hypotony, and conjunctival erosion by the extrascleral electronics case. This modified technique is suitable for the implantation of existing and forthcoming retinal prostheses. Superficial temporalis fascia may also be used as alternative to commercial tectonic tissues for scleral wound repair in clinical settings where they

  5. Intramuscular Haemangioma with Diagnostic Challenge: A Cause for Strange Pain in the Masseter Muscle

    PubMed Central

    Sankarapandiyan, Sathasivasubramanian; Pulivadula Mohanarangam, Venkata Sai

    2014-01-01

    Intramuscular hemangiomas are unique vascular tumors which are benign in nature, most commonly occurring in the trunk and extremities. When present in head and neck, they most frequently involve the masseter and trapezius muscles, accounting for less than 1% of all hemangiomas. Most of these lesions present with pain and discomfort and some patients may demonstrate progressive enlargement. Due to their infrequency, deep location, and unfamiliar presentation, these lesions are seldom correctly diagnosed clinically. Our report is a clinically misdiagnosed case of a painful soft tissue mass in the right side masseteric region of a 23-year-old female patient, confirmed as intramuscular hemangioma based on imaging studies and histopathologic examination, treated by surgical excision which had no recurrence after a 3-year followup. PMID:24995133

  6. Masseter flap for reconstruction of defects after excision of buccal mucosa cancers with intact mandible.

    PubMed

    Chaturvedi, Pankaj; Lerra, Sandeep; Ustad, Farheen; Pai, Prathamesh S; Chaukar, Devendra A; D'Cruz, Anil K

    2015-01-01

    Among the reconstructive options available for buccal mucosa defects with an intact mandible, free flap with microvascular anastomosis is the best option. However, in the developing world, with poor resources, limited infrastructure, and high patient load, this cannot be offered to all patients. We report on the success of the masseter flap for reconstruction of such defects in carefully selected patients. Despite some known limitations, this flap is easy to learn and carries acceptable complications. The results of this flap may not be comparable to those of microvascular reconstructions, but they are better than those from other options such as skin graft, nasolabial flap, submental flap, etc., in terms of surgical time required, no donor site morbidity, and minimal aesthetic deformity. PMID:26535825

  7. Positional relationships between the masticatory muscles and their innervating nerves with special reference to the lateral pterygoid and the midmedial and discotemporal muscle bundles of temporalis

    PubMed Central

    AKITA, KEIICHI; SHIMOKAWA, TAKASHI; SATO, TATSUO

    2000-01-01

    For an accurate assessment of jaw movement, it is crucial to understand the comprehensive formation of the masticatory muscles with special reference to the relationship to the disc of the temporomandibular joint. Detailed dissection was performed on 26 head halves of 14 Japanese cadavers in order to obtain precise anatomical information of the positional relationships between the masticatory muscles and the branches of the mandibular nerve. After complete removal of the bony elements, the midmedial muscle bundle in all specimens and the discotemporal muscle bundle in 6 specimens, derivatives of the temporalis, which insert into the disc were observed. On the anterior area of the articular capsule and the disc of the temporomandibular joint, the upper head of the lateral pterygoid, the midmedial muscle bundle of temporalis and the discotemporal bundle of temporalis were attached mediolaterally, and in 3 specimens the posterosuperior margin of the zygomaticomandibularis was attached to the anterolateral area of the disc. It is suggested that these muscles and muscle bundles contribute to various mandibular movements. Although various patterns of the positional relationships between the muscles and muscle bundles and the their innervating nerves are observed in the present study, relative positional relationships of the muscles and muscle bundles and of nerves of the mandibular nerve are consistent. A possible scheme of the developmental formation of the masticatory muscles based on the findings of the positional relationships between the muscles and the nerves is presented. PMID:11005720

  8. EMG Activity of Masseter Muscles in the Elderly According to Rheological Properties of Solid Food

    PubMed Central

    Kang, Au Jin; Kang, Si Hyun; Seo, Kyung Mook; Park, Hyoung Su; Park, Ki-Hwan

    2016-01-01

    Objective To assess the impact of aging on masticatory muscle function according to changes in hardness of solid food. Methods Each of fifteen healthy elderly and young people were selected. Subjects were asked to consume cooked rice, which was processed using the guidelines of the Universal Design Foods concept for elderly people (Japan Care Food Conference 2012). The properties of each cooked rice were categorized as grade 1, 2, 3 and 4 (5×103, 2×104, 5×104, and 5×105 N/m2) respectively. Surface electromyography (sEMG) was used to measure masseter activity from food ingestion to swallowing of test foods. The raw data was normalized by the ratio of sEMG activity to maximal voluntary contraction and compared among subjects. The data was divided according to each sequence of mastication and then calculated within the parameters of EMG activities. Results Intraoral tongue pressure was significantly higher in the young than in the elderly (p<0.05). Maximal value of average amplitude of the sequence in whole mastication showed significant positive correlation with hardness of food in both young and elderly groups (p<0.05). In a comparisons between groups, the maximal value of average amplitude of the sequence in whole mastication and peak amplitude in whole mastication showed that mastication in the elderly requires a higher percentage of maximal muscle activity than in the young, even with soft foods (p<0.05). Conclusion sEMG data of the masseter can provide valuable information to aid in the selection of foods according to hardness for the elderly. The results also support the necessity of specialized food preparation or products for the elderly. PMID:27446781

  9. Temperature dependent changes in cocaine- and amphetamine regulated transcript (CART) peptide in the brain of tadpole, Sylvirana temporalis.

    PubMed

    Shewale, Swapnil A; Gaupale, Tekchand C; Bhargava, Shobha

    2015-09-01

    Cocaine- and amphetamine-regulated transcript peptide (CARTp) has emerged as a novel neurotransmitter in the brain. Although the physiological role of the peptide has been intensely investigated in mammals, its role in amphibians has not been investigated. In the present study, an attempt has been undertaken to study the expression of CART in the tadpole brain of frog Sylvirana temporalis, subjected to thermal stress. Cells with strong CART-immunoreactivity were observed in the nucleus preoptic area (NPO) of tadpoles exposed to high temperature (37±2°C) as compared to those in the tadpoles exposed to low (12±2°C) and normal (24±2°C) temperatures. In the ventromedial thalamic nucleus (VM) and nucleus posterocentralis thalami (NPC), moderate CART-ir cells were observed in the control groups while number of cells and intensity of immunoreactivity was increased in tadpoles at low and high temperatures. In the nucleus infundibularis ventralis (NIV) and raphe nucleus (RA), CART immunoreactivity increased in the low as well as high temperature treated groups. Intensely stained CART cells were observed in the pituitary of tadpoles exposed to high temperature as compared to low temperature and control groups. We suggest that CART system in the brain and pituitary of tadpole may play a very important role in mediating responses to temperature variations in the environment. PMID:24983774

  10. Serotonin, glutamate and glycerol are released after the injection of hypertonic saline into human masseter muscles – a microdialysis study

    PubMed Central

    2014-01-01

    Background Chronic myalgia is associated with higher muscle levels of certain algesic biomarkers. The aim of this study was to investigate if hypertonic saline-induced jaw myalgia also leads to release of such biomarkers and if there were any sex differences in this respect. Methods Healthy participants, 15 men and 15 aged-matched women (25.7 ± 4.3 years) participated. Intramuscular microdialysis into masseter muscles was performed to sample serotonin (5-HT), glutamate, lactate, pyruvate, glucose and glycerol. After 2 hours 0.2 mL hypertonic saline (58.5 mg/mL) was injected into the masseter on one side and 0.2 mL isotonic saline (9 mg/mL) into the contralateral masseter close to the microdialysis catheter. Microdialysis continued for 1 hour after the injections. Pressure pain thresholds (PPT) and pain were assessed before and after injections. Results The median (IQR) peak pain intensity (0–100 visual analogue scale) after hypertonic saline was 52.5 (38.0) and after isotonic saline 7.5 (24.0) (p < 0.05). 5-HT, glutamate and glycerol increased after hypertonic saline injection (p < 0.05). Lactate, pyruvate and glucose showed no change. PPT after microdialysis was reduced on both sides (p < 0.05) but without side differences. Pain after hypertonic saline injection correlated positively to 5-HT (p < 0.05) and negatively to glycerol (p < 0.05). Conclusions 5-HT, glutamate and glycerol increased after a painful hypertonic saline injection into the masseter muscle, but without sex differences. Since increased levels of 5-HT and glutamate have been reported in chronic myalgia, this strengthens the validity of the pain model. Glycerol warrants further investigations. PMID:25519464

  11. The human masseter muscle and its biological correlates: A review of published data pertinent to face prediction.

    PubMed

    Stephan, Carl N

    2010-09-10

    The masseter muscle forms a cornerstone of anatomical facial reconstruction (FR) methods, yet it is only scantily described in the FR literature despite relatively intense research focus from other disciplines. This suggests that much more data exists for masseter prediction than that which is currently used in FR. This paper reviews the masseter muscle and finds that highly pertinent anatomical and metric data to be available despite being overlooked in the FR literature. This includes variance and means of the perimeter dimensions, thicknesses, cross-sectional areas, volumes, metrics associated with muscle attachment, and correlations with other biological and craniometric variables (such as sex, age, tooth loss, cranial breadths, facial heights, alveolar thicknesses, and gonial angles). The oversight of these metric data adds to a general pattern seen for other hallmark structures of the face in FR and, taken together, these observations hold major ramifications for longstanding debates of FR accuracy, reliability, and error. Irrespectively, the data reviewed in this manuscript help set an improved basis for quantification of FR techniques. PMID:20338704

  12. Influence of temporomandibular disorder on temporal and masseter muscles and occlusal contacts in adolescents: an electromyographic study

    PubMed Central

    2014-01-01

    Background The aim of the present study was to analyse the influence of temporomandibular disorder (TMD) on electromyographic activity in the masseter and temporal muscles of adolescents and investigate a possible association with the number of occlusal contacts. Methods The Helkimo Index was administered for the diagnosis of TMD and classification of the adolescents into three groups: without TMD; with mild TMD; and with moderate/severe TMD. Carbon paper was used for the determination of occlusal contact points. A standardised electromyographic evaluation was performed on the masticatory muscles at rest, during habitual chewing and during maximum voluntary clenching. The readings were normalised to maximum voluntary clenching. Statistical analysis involved the chi-squared test and Fisher’s exact test. The Kruskal-Wallis test and one-way analysis of variance with Dunn’s post hoc test were used to compare differences between groups. Pearson’s correlation coefficients (r) were calculated for the determination of correlations between the number of occlusal contacts and RMS values. Results Electromyography revealed significant differences in the right and left masseter and temporal muscles at rest and during chewing among the three groups. These differences were not observed during maximum voluntary clenching. No statistically significant differences were found between the groups with and without TMD regarding the number of occlusal contacts. Conclusion Electromyographic activity in the masseter and temporal muscles was greater among adolescents with moderate to severe TMD. PMID:24721559

  13. Functions of miR-1 and miR-133a during the postnatal development of masseter and gastrocnemius muscles.

    PubMed

    Nariyama, Megumi; Mori, Manami; Shimazaki, Emi; Ando, Hitoshi; Ohnuki, Yoshiki; Abo, Tokuhisa; Yamane, Akira; Asada, Yoshinobu

    2015-09-01

    The present study investigated the function of miR-1 and miR-133a during the postnatal development of mouse skeletal muscles. The amounts of miR-1 and miR-133a were measured in mouse masseter and gastrocnemius muscles between 1 and 12 weeks after birth with real-time polymerase chain reaction and those of HDACs, MEF2, MyoD family, MCK, SRF, and Cyclin D1 were measured at 2 and 12 weeks with Western blotting. In both the masseter and gastrocnemius muscles, the amount of miR-1 increased between 1 and 12 weeks, whereas the amount of HADC4 decreased between 2 and 12 weeks. In the masseter muscle, those of MEF2, MyoD, Myogenin, and MCK increased between 2 and 12 weeks, whereas, in the gastrocnemius muscle, only those of MRF4 and MCK increased. The extent of these changes in the masseter muscle was greater than that in the gastrocnemius muscle. The amounts of miR-133a, SRF, and Cyclin D1 did not change significantly in the masseter muscle between 1 and 12 weeks after birth. By contrast, in the gastrocnemius muscle, the amounts of miR-133a and Cyclin D1 increased, whereas that of SRF decreased. Our findings suggest that the regulatory pathway of miR-1 via HDAC4 and MEF2 plays a more prominent role during postnatal development in the masseter muscle than in the gastrocnemius muscle, whereas that of miR-133a via SRF plays a more prominent role in the gastrocnemius muscle than in the masseter muscle. PMID:25981536

  14. Isolation and Pharmacological Characterization of α-Elapitoxin-Ot1a, a Short-Chain Postsynaptic Neurotoxin from the Venom of the Western Desert Taipan, Oxyuranus temporalis

    PubMed Central

    Barber, Carmel M.; Ahmad Rusmili, Muhamad Rusdi; Hodgson, Wayne C.

    2016-01-01

    Taipans (Oxyuranus spp.) are elapids with highly potent venoms containing presynaptic (β) and postsynaptic (α) neurotoxins. O. temporalis (Western Desert taipan), a newly discovered member of this genus, has been shown to possess venom which displays marked in vitro neurotoxicity. No components have been isolated from this venom. We describe the characterization of α-elapitoxin-Ot1a (α-EPTX-Ot1a; 6712 Da), a short-chain postsynaptic neurotoxin, which accounts for approximately 30% of O. temporalis venom. α-Elapitoxin-Ot1a (0.1–1 µM) produced concentration-dependent inhibition of indirect-twitches, and abolished contractile responses to exogenous acetylcholine and carbachol, in the chick biventer cervicis nerve-muscle preparation. The inhibition of indirect twitches by α-elapitoxin-Ot1a (1 µM) was not reversed by washing the tissue. Prior addition of taipan antivenom (10 U/mL) delayed the neurotoxic effects of α-elapitoxin-Ot1a (1 µM) and markedly attenuated the neurotoxic effects of α-elapitoxin-Ot1a (0.1 µM). α-Elapitoxin-Ot1a displayed pseudo-irreversible antagonism of concentration-response curves to carbachol with a pA2 value of 8.02 ± 0.05. De novo sequencing revealed the main sequence of the short-chain postsynaptic neurotoxin (i.e., α-elapitoxin-Ot1a) as well as three other isoforms found in O. temporalis venom. α-Elapitoxin-Ot1a shows high sequence similarity (i.e., >87%) with other taipan short-chain postsynaptic neurotoxins. PMID:26938558

  15. Sarcoglycan Complex in Masseter and Sternocleidomastoid Muscles of Baboons: An Immunohistochemical Study

    PubMed Central

    Cutroneo, G.; Centofanti, A.; Speciale, F.; Rizzo, G.; Favaloro, A.; Santoro, G.; Bruschetta, D.; Milardi, D.; Micali, A.; Di Mauro, D.; Vermiglio, G.; Anastasi, G.; Trimarchi, F.

    2015-01-01

    The sarcoglycan complex consists of a group of single-pass transmembrane glycoproteins that are essential to maintain the integrity of muscle membranes. Any mutation in each sarcoglycan gene causes a series of recessive autosomal dystrophin-positive muscular dystrophies. Negative fibres for sarcoglycans have never been found in healthy humans and animals. In this study, we have investigated whether the social ranking has an influence on the expression of sarcoglycans in the skeletal muscles of healthy baboons. Biopsies of masseter and sternocleidomastoid muscles were processed for confocal immunohistochemical detection of sarcoglycans. Our findings showed that baboons from different social rankings exhibited different sarcoglycan expression profiles. While in dominant baboons almost all muscles were stained for sarcoglycans, only 55% of muscle fibres showed a significant staining. This different expression pattern is likely to be due to the living conditions of these primates. Sarcoglycans which play a key role in muscle activity by controlling contractile forces may influence the phenotype of muscle fibres, thus determining an adaptation to functional conditions. We hypothesize that this intraspecies variation reflects an epigenetic modification of the muscular protein network that allows baboons to adapt progressively to a different social status. PMID:26150161

  16. Biosignal Analysis to Assess Mental Stress in Automatic Driving of Trucks: Palmar Perspiration and Masseter Electromyography

    PubMed Central

    Zheng, Rencheng; Yamabe, Shigeyuki; Nakano, Kimihiko; Suda, Yoshihiro

    2015-01-01

    Nowadays insight into human-machine interaction is a critical topic with the large-scale development of intelligent vehicles. Biosignal analysis can provide a deeper understanding of driver behaviors that may indicate rationally practical use of the automatic technology. Therefore, this study concentrates on biosignal analysis to quantitatively evaluate mental stress of drivers during automatic driving of trucks, with vehicles set at a closed gap distance apart to reduce air resistance to save energy consumption. By application of two wearable sensor systems, a continuous measurement was realized for palmar perspiration and masseter electromyography, and a biosignal processing method was proposed to assess mental stress levels. In a driving simulator experiment, ten participants completed automatic driving with 4, 8, and 12 m gap distances from the preceding vehicle, and manual driving with about 25 m gap distance as a reference. It was found that mental stress significantly increased when the gap distances decreased, and an abrupt increase in mental stress of drivers was also observed accompanying a sudden change of the gap distance during automatic driving, which corresponded to significantly higher ride discomfort according to subjective reports. PMID:25738768

  17. Biosignal analysis to assess mental stress in automatic driving of trucks: palmar perspiration and masseter electromyography.

    PubMed

    Zheng, Rencheng; Yamabe, Shigeyuki; Nakano, Kimihiko; Suda, Yoshihiro

    2015-01-01

    Nowadays insight into human-machine interaction is a critical topic with the large-scale development of intelligent vehicles. Biosignal analysis can provide a deeper understanding of driver behaviors that may indicate rationally practical use of the automatic technology. Therefore, this study concentrates on biosignal analysis to quantitatively evaluate mental stress of drivers during automatic driving of trucks, with vehicles set at a closed gap distance apart to reduce air resistance to save energy consumption. By application of two wearable sensor systems, a continuous measurement was realized for palmar perspiration and masseter electromyography, and a biosignal processing method was proposed to assess mental stress levels. In a driving simulator experiment, ten participants completed automatic driving with 4, 8, and 12 m gap distances from the preceding vehicle, and manual driving with about 25 m gap distance as a reference. It was found that mental stress significantly increased when the gap distances decreased, and an abrupt increase in mental stress of drivers was also observed accompanying a sudden change of the gap distance during automatic driving, which corresponded to significantly higher ride discomfort according to subjective reports. PMID:25738768

  18. Morphological and molecular characterization of Isospora neochmiae n. sp. in a captive-bred red-browed finch (Neochmia temporalis) (Latham, 1802).

    PubMed

    Yang, Rongchang; Brice, Belinda; Ryan, Una

    2016-07-01

    A new Isospora (Apicomplexa: Eimeriidae) species is described from a single red-browed finch (Neochmia temporalis) (subspecies N. temporalis temporalis), that was part of a captive population in Western Australia. Sporulated oocysts of this isolate are spherical, 18.3 (18.2-18.9) × 18.2 (18.2-18.6) μm, with a shape index (length/width) of 1.0; and a smooth and bilayered oocyst wall, 1.2 μm thick (outer layer 0.9 μm, inner 0.3 μm). A polar granule is present, but the oocyst residuum and a micropyle are absent. The sporocysts are ovoid-shaped, 13.3 (9.5-16.4) × 8.6 (6.8-10.0) μm, with a shape index of 1.5. An indistinct Stieda body is present, but the substieda body is absent. A sporocyst residuum is present and composed of numerous granules of different size scattered among the sporozoites. Morphologically, the oocysts from this isolate are different from those of all known valid Isospora spp. Molecular analysis was conducted at 4 loci; the 18S and 28S ribosomal RNA (rRNA), the mitochondrial cytochrome oxidase (COI) gene and the heat shock protein 70 (hsp70) gene. At the 18S locus, this new isolate exhibited 99.9%, 99.8%, 99.7%, and 99.5% similarity to I. sp. MAH-2013a from a superb starling (Lamprotornis superbus), I. MS-2003 from a Southern cape sparrow (Passer melanurus), I. sp. Tokyo from a domestic pigeon (Columba livia domestica) and I. MS-2003 from a Surinam crested oropendula (Psarocolius decumanus). At the 28S locus, this new isolate exhibited 99.7% similarity to both an Isospora sp (MS-2003) from a Northern house sparrow (Passer domesticus) and an Isospora sp. (MS-2003) from a Southern cape sparrow. At the COI locus, this new isolate exhibited 98.9% similarity to an Isospora sp. ex Apodemus flavicollis. At the hsp70 locus, this new isolate exhibited 99% similarity to isolate MS-2003 (AY283879) from a wattled starling (Creatophora cinerea). Based on morphological and molecular data, this isolate is a new species of Isospora, which is named

  19. Effect of experimental jaw-muscle pain on the spatial distribution of surface EMG activity of the human masseter muscle during tooth clenching.

    PubMed

    Castroflorio, T; Falla, D; Wang, K; Svensson, P; Farina, D

    2012-02-01

    This study tested the hypothesis that painful injections of glutamate into the human masseter muscle differentially affect the distribution of the electromyographic (EMG) activity in the masseter muscle at rest and during tooth clenching. Surface EMG signals were recorded bilaterally from the superficial masseter of nine healthy men with a grid of 32 electrodes, before and after intramuscular injection of glutamate or isotonic saline, during rest and isometric contractions at 20%, 40%, 60% and 80% of the maximal voluntary bite force. Intramuscular injection of glutamate evoked moderate pain (0-10 visual analogue scale: 6·4 ± 1·4), with sensory-discriminative characteristics of the perceived pain, evaluated with the use of the McGill Pain Questionnaire (MPQ), similar to those previously reported for patients with temporomandibular disorders. There was no effect of the glutamate injection on EMG amplitude during rest, whereas during tooth clenching, the spatial distribution of the masseter EMG activity on both sides was more uniform in the painful condition compared to the control condition. Moreover, the overall EMG amplitude decreased on both sides during the more forceful tooth clenching following glutamate injection. In conclusion, a unilateral painful stimulation was associated with a bilateral inhibition of the masseter muscles during tooth clenching which resulted in a more uniform distribution of EMG activity. PMID:21848526

  20. A study on synaptic coupling between single orofacial mechanoreceptors and human masseter muscle.

    PubMed

    Türker, Kemal S; Johnsen, Skjalg E; Sowman, Paul F; Trulsson, Mats

    2006-04-01

    The connection between individual orofacial mechanoreceptive afferents and the motoneurones that innervate jaw muscles is not well established. For example, although electrical and mechanical stimulation of orofacial afferents in bulk evokes responses in the jaw closers, whether similar responses can be evoked in the jaw muscles from the discharge of type identified single orofacial mechanoreceptive afferents is not known. Using tungsten microelectrodes, we have recorded from 28 afferents in the inferior alveolar nerve and 21 afferents in the lingual nerve of human volunteers. We have used discharges of single orofacial afferents as the triggers and the electromyogram (EMG) of the masseter as the source to generate spike-triggered averaged records to illustrate time-based EMG modulation by the nerve discharge. We have then used cross correlation analysis to quantify the coupling. Furthermore, we have also used coherence analysis to study frequency-based relationship between the nerve spike trains and the EMG. The discharge patterns of the skin and mucosa receptors around the lip and the gingiva generated significant modulation in EMGs with a success rate of 40% for both cross correlation and coherence analyses. The discharge patterns of the periodontal mechanoreceptors (PMRs) generated more coupling with a success rate of 70% for cross correlation and about 35% for coherence analyses. Finally, the discharges of the tongue receptors displayed significant coupling with the jaw muscle motoneurones with a success rate of about 40% for both analyses. Significant modulation of the jaw muscles by single orofacial receptors suggests that they play important roles in controlling the jaw muscle activity so that mastication and speech functions are executed successfully. PMID:16328261

  1. Involvement of IL-1 in the Maintenance of Masseter Muscle Activity and Glucose Homeostasis

    PubMed Central

    Chiba, Ko; Tsuchiya, Masahiro; Koide, Masashi; Hagiwara, Yoshihiro; Sasaki, Keiichi; Hattori, Yoshinori; Watanabe, Makoto; Sugawara, Shunji; Kanzaki, Makoto; Endo, Yasuo

    2015-01-01

    Physical exercise reportedly stimulates IL-1 production within working skeletal muscles, but its physiological significance remains unknown due to the existence of two distinct IL-1 isoforms, IL-1α and IL-1β. The regulatory complexities of these two isoforms, in terms of which cells in muscles produce them and their distinct/redundant biological actions, have yet to be elucidated. Taking advantage of our masticatory behavior (Restrained/Gnawing) model, we herein show that IL-1α/1β-double-knockout (IL-1-KO) mice exhibit compromised masseter muscle (MM) activity which is at least partially attributable to abnormalities of glucose handling (rapid glycogen depletion along with impaired glucose uptake) and dysfunction of IL-6 upregulation in working MMs. In wild-type mice, masticatory behavior clearly increased IL-1β mRNA expression but no incremental protein abundance was detectable in whole MM homogenates, whereas immunohistochemical staining analysis revealed that both IL-1α- and IL-1β-immunopositive cells were recruited around blood vessels in the perimysium of MMs after masticatory behavior. In addition to the aforementioned phenotype of IL-1-KO mice, we found the IL-6 mRNA and protein levels in MMs after masticatory behavior to be significantly lower in IL-1-KO than in WT. Thus, our findings confirm that the locally-increased IL-1 elicited by masticatory behavior, although present small in amounts, contributes to supporting MM activity by maintaining normal glucose homeostasis in these muscles. Our data also underscore the importance of IL-1-mediated local interplay between autocrine myokines including IL-6 and paracrine cytokines in active skeletal muscles. This interplay is directly involved in MM performance and fatigability, perhaps mediated through maintaining muscular glucose homeostasis. PMID:26599867

  2. Molecular Motor MYO1C, Acetyltransferase KAT6B and Osteogenetic Transcription Factor RUNX2 Expression in Human Masseter Muscle Contributes to Development of Malocclusion

    PubMed Central

    Desh, Heather; Gray, S Lauren; Horton, Michael J; Raoul, Gwenael; Rowlerson, Anthea M; Ferri, Joel; Vieira, Alexandre R; Sciote, James J

    2014-01-01

    Objective Type I myosins are molecular motors necessary for glucose transport in the cytoplasm and initiation of transcription in the nucleus. Two of these, MYO1H and MYO1C, are paralogs which may be important in the development of malocclusion. The objective of this study was to investigate their gene expression in the masseter muscle of malocclusion subjects. Two functionally related proteins known to contribute to malocclusion were also investigated: KAT6B (a chromatin remodeling epigenetic enzyme which is activated by MYO1C) and RUNX2 (a transcription factor regulating osteogenesis which is activated by KAT6B). Design Masseter muscle samples and malocclusion classifications were obtained from orthognathic surgery subjects. Muscle was sectioned and immunostained to determine fiber type properties. RNA was isolated from the remaining sample to determine expression levels for the four genes by TaqMan® RT-PCR. Fiber type properties, gene expression quantities and malocclusion classification were compared. Results There were very significant associations (P<0.0000001) between MYO1C and KAT6B expressions. There were also significant associations (P<0.005) between RUNX2 expression and masseter muscle type II fiber properties. Very few significant associations were identified between MYO1C and masseter muscle fiber type properties. Conclusions The relationship between MYO1C and KAT6B suggests that the two are interacting in chromatin remodeling for gene expression. This is the nuclear myosin1 (NM1) function of MYO1C. A surprising finding is the relationship between RUNX2 and type II masseter muscle fibers, since RUNX2 expression in mature muscle was previously unknown. Further investigations are necessary to elucidate the role of RUNX2 in adult masseter muscle. PMID:24698832

  3. Abundant expression of myosin heavy-chain IIB RNA in a subset of human masseter muscle fibres

    PubMed Central

    Horton, Michael J.; Brandon, Carla A.; Morris, Terence J.; Braun, Thomas W.; Yaw, Kenneth M.; Sciote, James J.

    2013-01-01

    Type IIB fast fibres are typically demonstrated in human skeletal muscle by histochemical staining for the ATPase activity of myosin heavy-chain (MyHC) isoforms. However, the monoclonal antibody specific for the mammalian IIB isoform does not detect MyHC IIB protein in man and MyHC IIX RNA is found in histochemically identified IIB fibres, suggesting that the IIB protein isoform may not be present in man; if this is not so, jaw-closing muscles, which express a diversity of isoforms, are likely candidates for their presence. ATPase histochemistry, immunohistochemistry polyacrylamide gel electrophoresis and in situ hybridization, which included a MyHC IIB-specific mRNA riboprobe, were used to compare the composition and RNA expression of MyHC isoforms in a human jaw-closing muscle, the masseter, an upper limb muscle, the triceps, an abdominal muscle, the external oblique, and a lower limb muscle, the gastrocnemius. The external oblique contained a mixture of histochemically defined type I, IIA and IIB fibres distributed in a mosaic pattern, while the triceps and gastrocnemius contained only type I and IIA fibres. Typical of limb muscle fibres, the MyHC I-specific mRNA probes hybridized with histochemically defined type I fibres, the IIA-specific probes with type IIA fibres and the IIX-specific probes with type IIB fibres. The MyHC IIB mRNA probe hybridized only with a few histochemically defined type I fibres in the sample from the external oblique; in addition to this IIB message, these fibres also expressed RNAs for MyHC I, IIA and IIX. MyHC IIB RNA was abundantly expressed in histochemical and immunohistochemical type IIA fibres of the masseter, together with transcripts for IIA and in some cases IIX. No MyHC IIB protein was detected in fibres and extracts of either the external oblique or masseter by immunohistochemistry, immunoblotting and electrophoresis. Thus, IIB RNA, but not protein, was found in the fibres of two different human skeletal muscles. It is

  4. Assessment of the Potential Role of Muscle Spindle Mechanoreceptor Afferents in Chronic Muscle Pain in the Rat Masseter Muscle

    PubMed Central

    Sadeghi, Somayeh; Athanassiadis, Tuija; Caram Salas, Nadia; Auclair, François; Thivierge, Benoît; Arsenault, Isabel; Rompré, Pierre; Westberg, Karl-Gunnar; Kolta, Arlette

    2010-01-01

    Background The phenotype of large diameter sensory afferent neurons changes in several models of neuropathic pain. We asked if similar changes also occur in “functional” pain syndromes. Methodology/Principal Findings Acidic saline (AS, pH 4.0) injections into the masseter muscle were used to induce persistent myalgia. Controls received saline at pH 7.2. Nocifensive responses of Experimental rats to applications of Von Frey Filaments to the masseters were above control levels 1–38 days post-injection. This effect was bilateral. Expression of c-Fos in the Trigeminal Mesencephalic Nucleus (NVmes), which contains the somata of masseter muscle spindle afferents (MSA), was above baseline levels 1 and 4 days after AS. The resting membrane potentials of neurons exposed to AS (n = 167) were hyperpolarized when compared to their control counterparts (n = 141), as were their thresholds for firing, high frequency membrane oscillations (HFMO), bursting, inward and outward rectification. The amplitude of HFMO was increased and spontaneous ectopic firing occurred in 10% of acid-exposed neurons, but never in Controls. These changes appeared within the same time frame as the observed nocifensive behaviour. Ectopic action potentials can travel centrally, but also antidromically to the peripheral terminals of MSA where they could cause neurotransmitter release and activation of adjacent fibre terminals. Using immunohistochemistry, we confirmed that annulospiral endings of masseter MSA express the glutamate vesicular transporter VGLUT1, indicating that they can release glutamate. Many capsules also contained fine fibers that were labelled by markers associated with nociceptors (calcitonin gene-related peptide, Substance P, P2X3 receptors and TRPV1 receptors) and that expressed the metabotropic glutamate receptor, mGluR5. Antagonists of glutamatergic receptors given together with the 2nd injection of AS prevented the hypersensitivity observed bilaterally but were

  5. Specific increase in non-functional masseter bursts in subjects aware of tooth-clenching during wakefulness.

    PubMed

    Katase-Akiyama, S; Kato, T; Yamashita, S; Masuda, Y; Morimoto, T

    2009-02-01

    Previous studies have reported that subjective awareness of a tooth-clenching habit is associated with increased jaw motor activity (Rao SM, Glaros AG, J Dent Res. 1979;58:1872). The aim of this study was to test the hypothesis that subjects with clenching awareness exhibit different motor expressions specific to non-functional oromotor activity under laboratory conditions without psychological or sensory effects. Polygraphic and audio-video recordings were made for a 30-min period of silent reading by 33 subjects without oro-facial pain. Oro-facial behaviours (e.g. swallowing, lip movements) were scored according to the polygraphic and audio-video records and masseter bursts were quantitatively analysed. Subjective psychological/sensory measures were also recorded before and/or after the polygraphic recording using a visual analogue scale. The subjects were classified into two groups one with 15 subjects who were aware of having a tooth-clenching habit and another with 18 who were not aware of any such habit. There were no differences between the groups with respect to the number of functional oro-facial behaviours or subjective psychological/sensory measures. Masseter bursts unrelated to functional oro-facial behaviours occurred more frequently in subjects with awareness [median (range) = 23 (2-187) bursts] than in those without [9.0 (0-36); P = 0.01], while neither burst activity [12.3 (1.8-34.5) % of maximum voluntary clenching and 10.1 (6.5-25.1) %, respectively] nor duration [1.17 (0.2-2.2) s and 1.28 (0.3-4.1) s, respectively] differed between the groups. The occurrence of functional oro-facial behaviours or other body behaviours (e.g. limb and body movements) did not differ between the two groups. These findings suggest that the increased masseter activity in subjects with tooth-clenching awareness is characterized by a specific increase in non-functional masseter bursts. PMID:18976275

  6. On the anatomy of the temporomandibular joint and the muscles that act upon it: observations on the gray whale, Eschrichtius robustus.

    PubMed

    El Adli, Joseph J; Deméré, Thomas A

    2015-04-01

    The temporomandibular joint and its associated musculature are described in a neonate gray whale (Eschrichtius robustus) and serve as the basis for direct anatomical comparisons with the temporomandibular region in other clades of baleen whales (Mysticeti). Members of the right whale/bowhead whale clade (Balaenidae) are known to possess a synovial lower jaw joint, while members of the rorqual clade (Balaenopteridae) have a nonsynovial temporomandibular joint characterized by a highly flexible fibrocartilaginous pad and no joint capsule. In contrast, the gray whale possesses a modified temporomandibular joint (intermediate condition), with a vestigial joint cavity lacking a fibrous capsule, synovial membrane, and articular disk. In addition, the presence of a rudimentary fibrocartilaginous pad appears to be homologous to that seen in balaenopterid mysticetes. The intrinsic temporomandibular musculature in the gray whale was found to include a multibellied superficial masseter and a single-bellied deep masseter. The digastric and internal pterygoid muscles in E. robustus are enlarged relative to the condition documented in species of Balaenoptera. A relatively complex insertion of the temporalis muscle on the dentary is documented in the gray whale and the low, knob-like process on the gray whale dentary is determined to be homologous with the prominent coronoid process of rorquals. Comparison with the anatomy of the temporomandibular musculature in rorquals reveals an increased importance of alpha rotation of the dentary in the gray whale. This difference in muscular morphology and lines of muscle action is interpreted as representing adaptations for suction feeding. PMID:25737135

  7. The effects of simultaneous but unequal response-independent pay to pairs of human subjects on masseter EMG and bodily movements. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Keenan, D. M.

    1974-01-01

    Electromyographic activity and bodily movement of the masseter muscle were recorded in three pairs of human subjects, where one member of each pair was systematically presented with greater pay and each could reduce the value of money received by the other. The number of biting responses was as high or higher for the subject receiving less money immediately after coin delivery. However, the number of masseter contractions for the subject receiving more money remained higher at other times during the unequal pay conditions. No responses of pay reduction were emitted by any subject toward another.

  8. Comparison of a microsliced modified chondroperichondrium shield graft and a temporalis fascia graft in primary type I tympanoplasty: A prospective randomized controlled trial.

    PubMed

    Bhattacharya, Shambhu Nath; Pal, Sudipta; Saha, Somnath; Gure, Prasanta Kumar; Roy, Anupam

    2016-07-01

    We conducted a prospective, randomized, controlled trial to compare outcomes in type I tympanoplasty patients who received an autologous microsliced modified cartilage perichondrium shield graft (cartilage group) and those who received an autologous temporalis muscle fascia graft (fascia group). Our three outcomes measures were (1) anatomic success rates at 3 months, (2) hearing results at 6 months, and (3) rates of morphologic success (i.e., the absence of reperforation, retraction, and graft displacement) at 2 years among those in each group who had an intact graft at 3 months. Of 56 patients who were initially enrolled and who underwent one of these type I tympanoplasty procedures, 51 completed the study-28 in the cartilage group and 23 in the fascia group. The former was made up of 11 males and 17 females, aged 15 to 48 years (mean: 27.4), and the latter included 9 males and 14 females, aged 15 to 52 years (mean: 31.7). The overall graft take rate at 3 months with respect to perforation closure (anatomic success) was 93.3% in the cartilage group and 91.7% in the fascia group, which was not a statistically significant difference. The mean hearing gain at 6 months was 11.7 ± 7.6 dB in the cartilage group and 12.6 ± 6.0 dB in the fascia group-again, not statistically significant. At 2 years, morphologic success rates were 92.3 and 81.0%, respectively-again, not statistically significant. We conclude that autologous microsliced modified cartilage perichondrium shield graft tympanoplasty is as effective as conventional temporalis fascia tympanoplasty in terms of graft take rates and functional results. Indeed, medium-term outcomes (2-yr follow-up) revealed that sustainable morphologic success was actually better with the cartilage technique than with the fascia technique because it was associated with fewer revision surgeries. PMID:27434476

  9. Brainstem neurons responsible for postural, masseter or pharyngeal muscle atonia during paradoxical sleep in freely-moving cats.

    PubMed

    Sakai, K; Neuzeret, P-C

    2011-12-01

    In this mini review, we summarize our findings regarding the brainstem neurons responsible for the postural, masseter, or pharyngeal muscle atonia observed during paradoxical sleep (PS) in freely moving cats. Both the pons and medulla contain neurons showing tonic activation selective to PS and atonia, referred to as PS/atonia-on-neurons. The PS/atonia-on neurons, characterized by their most slow conducting property and located in the peri-locus coeruleus alpha (peri-LCa) and adjacent LCa of the mediodorsal pontine tegmentum, play a critical executive role in the somatic and orofacial muscle atonia observed during PS. Slow conducting medullary PS/atonia-on neurons located in the nuclei reticularis magnocellularis (Mc) and parvocellularis (Pc) may play a critical executive role in the generation of, respectively, antigravity or orofacial muscle atonia during PS. In addition, either tonic or phasic cessation of activity of medullary serotonergic neurons may play an important role in the atonia of genioglossus muscles during PS via a mechanism of disfacilitation. PMID:22205587

  10. What Determines Habitat Quality for a Declining Woodland Bird in a Fragmented Environment: The Grey-Crowned Babbler Pomatostomus temporalis in South-Eastern Australia?

    PubMed Central

    Stevens, Kate P.; Holland, Greg J.; Clarke, Rohan H.; Cooke, Raylene; Bennett, Andrew F.

    2015-01-01

    Understanding what constitutes high quality habitat is crucial for the conservation of species, especially those threatened with extinction. Habitat quality frequently is inferred by comparing the attributes of sites where a species is present with those where it is absent. However, species presence may not always indicate high quality habitat. Demographic parameters are likely to provide a more biologically relevant measure of quality, including a species’ ability to successfully reproduce. We examined factors believed to influence territory quality for the grey-crowned babbler (Pomatostomus temporalis), a cooperatively breeding woodland bird that has experienced major range contraction and population decline in south-eastern Australia. Across three broad regions, we identified active territories and determined the presence of fledglings and the size of family groups, as surrogates of territory quality. These measures were modelled in relation to habitat attributes within territories, the extent of surrounding wooded vegetation, isolation from neighbouring groups, and the size of the neighbourhood population. Fledgling presence was strongly positively associated with group size, indicating that helpers enhance breeding success. Surprisingly, no other territory or landscape-scale variables predicted territory quality, as inferred from either breeding success or group size. Relationships between group size and environmental variables may be obscured by longer-term dynamics in group size. Variation in biotic interactions, notably competition from the noisy miner (Manorina melanocephala), also may contribute. Conservation actions that enhance the number and size of family groups will contribute towards reversing declines of this species. Despite associated challenges, demographic studies have potential to identify mechanistic processes that underpin population performance; critical knowledge for effective conservation management. PMID:26098355

  11. Noradrenergic modulation of masseter muscle activity during natural rapid eye movement sleep requires glutamatergic signalling at the trigeminal motor nucleus.

    PubMed

    Schwarz, Peter B; Mir, Saba; Peever, John H

    2014-08-15

    Noradrenergic neurotransmission in the brainstem is closely coupled to changes in muscle activity across the sleep-wake cycle, and noradrenaline is considered to be a key excitatory neuromodulator that reinforces the arousal-related stimulus on motoneurons to drive movement. However, it is unknown if α-1 noradrenoceptor activation increases motoneuron responsiveness to excitatory glutamate (AMPA) receptor-mediated inputs during natural behaviour. We studied the effects of noradrenaline on AMPA receptor-mediated motor activity at the motoneuron level in freely behaving rats, particularly during rapid eye movement (REM) sleep, a period during which both AMPA receptor-triggered muscle twitches and periods of muscle quiescence in which AMPA drive is silent are exhibited. Male rats were subjected to electromyography and electroencephalography recording to monitor sleep and waking behaviour. The implantation of a cannula into the trigeminal motor nucleus of the brainstem allowed us to perfuse noradrenergic and glutamatergic drugs by reverse microdialysis, and thus to use masseter muscle activity as an index of motoneuronal output. We found that endogenous excitation of both α-1 noradrenoceptor and AMPA receptors during waking are coupled to motor activity; however, REM sleep exhibits an absence of endogenous α-1 noradrenoceptor activity. Importantly, exogenous α-1 noradrenoceptor stimulation cannot reverse the muscle twitch suppression induced by AMPA receptor blockade and nor can it elevate muscle activity during quiet REM, a phase when endogenous AMPA receptor activity is subthreshold. We conclude that the presence of an endogenous glutamatergic drive is necessary for noradrenaline to trigger muscle activity at the level of the motoneuron in an animal behaving naturally. PMID:24860176

  12. Role of cyclic AMP sensor Epac1 in masseter muscle hypertrophy and myosin heavy chain transition induced by β2-adrenoceptor stimulation.

    PubMed

    Ohnuki, Yoshiki; Umeki, Daisuke; Mototani, Yasumasa; Jin, Huiling; Cai, Wenqian; Shiozawa, Kouichi; Suita, Kenji; Saeki, Yasutake; Fujita, Takayuki; Ishikawa, Yoshihiro; Okumura, Satoshi

    2014-12-15

    The predominant isoform of β-adrenoceptor (β-AR) in skeletal muscle is β2-AR and that in the cardiac muscle is β1-AR. We have reported that Epac1 (exchange protein directly activated by cAMP 1), a new protein kinase A-independent cAMP sensor, does not affect cardiac hypertrophy in response to pressure overload or chronic isoproterenol (isoprenaline) infusion. However, the role of Epac1 in skeletal muscle hypertrophy remains poorly understood. We thus examined the effect of disruption of Epac1, the major Epac isoform in skeletal muscle, on masseter muscle hypertrophy induced by chronic β2-AR stimulation with clenbuterol (CB) in Epac1-null mice (Epac1KO). The masseter muscle weight/tibial length ratio was similar in wild-type (WT) and Epac1KO at baseline and was significantly increased in WT after CB infusion, but this increase was suppressed in Epac1KO. CB treatment significantly increased the proportion of myosin heavy chain (MHC) IIb at the expense of that of MHC IId/x in both WT and Epac1KO, indicating that Epac1 did not mediate the CB-induced MHC isoform transition towards the faster isoform. The mechanism of suppression of CB-mediated hypertrophy in Epac1KO is considered to involve decreased activation of Akt signalling. In addition, CB-induced histone deacetylase 4 (HDAC4) phosphorylation on serine 246 mediated by calmodulin kinase II (CaMKII), which plays a role in skeletal muscle hypertrophy, was suppressed in Epac1KO. Our findings suggest that Epac1 plays a role in β2-AR-mediated masseter muscle hypertrophy, probably through activation of both Akt signalling and CaMKII/HDAC4 signalling. PMID:25344550

  13. Non-specific esterases and esterproteases in masticatory muscles from the muscular dystrophic mouse.

    PubMed

    Kirkeby, S; Moe, D; Vilmann, H

    1989-03-01

    With the aid of histochemical and electrophoretic techniques activities for esterase and esterprotease were investigated in the digastric and masseter muscles from normal and dystrophic mice. The substrates used were alpha-naphthyl acetate and N-acetyl-L-alanine alpha-naphthyl ester. According to the microscopic observations of the dystrophic muscles the histopathological changes in the masseter muscle were much more pronounced than in the digastric muscle. The connective tissue surrounding the myofibers of the dystrophic masseter contained a large number of cells with pronounced enzyme activity. Among them were mast cells that were strongly stained for esterprotease. The connective tissue of the dystrophic digastricus was much less infiltrated with cellular elements reacting for esterprotease. In zymograms the normal digastricus, the dystrophic masseter and the dystrophic digastricus showed a strong activity for certain isoenzymes that were absent or weakly expressed in the normal masseter. PMID:2657470

  14. Jaw Dysfunction Related to Pterygoid and Masseter Muscle Dosimetry After Radiation Therapy in Children and Young Adults With Head-and-Neck Sarcomas

    SciTech Connect

    Krasin, Matthew J.; Wiese, Kristin M.; Spunt, Sheri L.; Hua, Chia-ho; Daw, Najat; Navid, Fariba; Davidoff, Andrew M.; McGregor, Lisa; Merchant, Thomas E.; Kun, Larry E.; McCrarey, Lola; and others

    2012-01-01

    Purpose: To investigate the relationship between jaw function, patient and treatment variables, and radiation dosimetry of the mandibular muscles and joints in children and young adults receiving radiation for soft-tissue and bone sarcomas. Methods and Materials: Twenty-four pediatric and young adult patients with head-and-neck sarcomas were treated on an institutional review board-approved prospective study of focal radiation therapy for local tumor control. Serial jaw depression measurements were related to radiation dosimetry delivered to the medial and lateral pterygoid muscles, masseter muscles, and temporomandibular joints to generate mathematical models of jaw function. Results: Baseline jaw depression was only influenced by the degree of surgical resection. In the first 12 weeks from initiation of radiation, surgical procedures greater than a biopsy, administration of cyclophosphamide containing chemotherapy regimes, and large gross tumor volumes adversely affected jaw depression. Increasing dose to the pterygoid and masseter muscles above 40 Gy predicted loss of jaw function over the full course of follow-up. Conclusions: Clinical and treatment factors are related to initial and subsequent jaw dysfunction. Understanding these complex interactions and the affect of specific radiation doses may help reduce the risk for jaw dysfunction in future children and young adults undergoing radiation therapy for the management of soft-tissue and bone sarcomas.

  15. Effects of excitation of sensory pathways on the membrane potential of cat masseter motoneurons before and during cholinergically induced motor atonia.

    PubMed

    Kohlmeier, K A; López-Rodríguez, F; Morales, F R; Chase, M H

    1998-09-01

    Electrical stimulation of the nucleus pontis oralis during wakefulness enhances somatic reflex activity; identical stimuli during the motor atonia of active (rapid eye movement) sleep induces reflex suppression. This phenomenon, which is called reticular response-reversal, is based upon the generation of excitatory postsynaptic potential activity in motoneurons during wakefulness and inhibitory postsynaptic potential activity during the motor atonia of active sleep. In the present study, instead of utilizing artificial electrical stimulation to directly excite brainstem structures, we sought to examine the effects on motoneurons of activation of sensory pathways by exogenously applied stimuli (auditory) and by stimulation of a peripheral (sciatic) nerve. Accordingly, we examined the synaptic response of masseter motoneurons prior to and during cholinergically induced motor atonia in a pharmacological model of active sleep-specific motor atonia, the alpha-chloralose-anesthetized cat, to two different types of afferent input, one of which has been previously demonstrated to elicit excitatory motor responses during wakefulness. Following the pontine injection of carbachol, auditory stimuli (95 dB clicks) elicited a hyperpolarizing potential in masseter motoneurons. Similar responses were obtained upon stimulation of the sciatic nerve. Responses of this nature were never seen prior to the injection of carbachol. Thus, stimulation of two different afferent pathways (auditory and somatosensory) that produce excitatory motor responses during wakefulness instead, during motor atonia, results in the inhibition of masseter motoneurons. The switching of the net result of the synaptic response from one of potential motor excitation to primarily inhibition in response to the activation of sensory pathways was comparable to the phenomenon of reticular response-reversal. This is the first report to examine the synaptic mechanisms whereby exogenously or peripherally applied

  16. Re-examination of the surface EMG activity of the masseter muscle in young adults during chewing of two test foods.

    PubMed

    Karkazis, H C; Kossioni, A E

    1997-03-01

    The purpose of this study was to investigate the effect of the texture of food on the masseter EMG activity during chewing. Fresh raw carrots and non-adhesive chewing gums of similar size and weight were used as representing a hard and a soft food respectively. The mean values for the IEMG activity, the duration of the chewing cycle, the chewing rate and the relative contraction time during chewing were significantly higher for the carrots while no significant difference was found in the chewing burst duration between the two test foods. Finally a strong inverse correlation was found between chewing rate and cycle duration. It was concluded that the texture of food has an obvious effect on EMG activity during chewing and that adjustments to changes in food consistency are made mainly by altering the chewing rate, the duration of the chewing cycle and the IEMG activity. PMID:9131477

  17. Bilateral myositis ossificans of the masseter muscle after chemoradiotherapy and critical illness neuropathy- report of a rare entity and review of literature

    PubMed Central

    Kruse, Astrid L; Dannemann, Christine; Grätz, Klaus W

    2009-01-01

    Myositis ossificans in the head and neck is a rare heterotropic bone formation within a muscle. Besides fibrodysplasia ossificans progressiva, traumatic and neurogenic forms are described in the literature. We are presenting the case of a 35-year-old female patient with a very rare form of MO of both masseter muscles after 4 weeks of intensive care because of complications (critical illness neuropathy) after chemotherapy. Therefore, special attention should be paid to surgical trauma. As in the present case, radiotherapy, long-time intubation with immobilization and critical myopathy and neuropathy can cause MO with severe problems, such as trismus and reduced mouth hygiene, which can lead to reduced quality of life. PMID:19674466

  18. Test-Retest Reliability of Detection Time Data Measured Using a Masseter Electromyogram in Healthy Young Adults: Preliminary Analysis of Data.

    PubMed

    Miyaoka, Satomi; Miyaoka, Yozo

    2016-04-01

    Few studies have assessed test-retest reliability of flavor detection time in semisolid and solid foods. In this study, test-retest reliability was assessed in 16 healthy young adults (22.6 ± 5.5 years old) on the data collected using a masseter electromyography-based system between two experimental sessions approximately 35 days apart. The overall correlation coefficients were calculated across five test foods; the correlation coefficient for the entire sample was statistically significant. Five correlation coefficients were calculated for individual test foods, but only orange-flavored gummy candy was significantly correlated across the two sessions. These results suggested that flavor detection time measured by the electromyography-based system is basically reliable over time, with considerable variation among flavors. PMID:27166330

  19. Exteroceptive silent period of masseter muscle activity evoked by electrical mental nerve stimulation: relation to non-pain and pain sensations.

    PubMed

    Strenge, H; Zichner, V; Niederberger, U

    1996-01-01

    Exteroceptive silent periods (ESPs) of masseter muscle activity evoked by electrical stimulation of the mental nerve were studied over a large range of prepain intensities and at pain threshold in 44 normal subjects. Seven levels of stimulus intensity, based on individual sensory and pain thresholds, were applied and the relationship between ESPs, stimulus intensity and perception, as manifested by the subjective verbal response, was investigated. The analysis revealed that the occurrence of ESPs was not related to the stimulus intensity at the pain threshold. There were individually different patterns of progressive response to increasing current intensities within the pre-pain range in many cases. On the other hand, almost half of all the subjects investigated showed no or only occasional ESPs. In view of this variability the concept of ESPs being a nociceptive behavioural response has to be questioned. PMID:8936454

  20. Peripheral G protein-coupled inwardly rectifying potassium (GIRK) channels are involved in delta opioid receptor-mediated anti-hyperalgesia in rat masseter muscle

    PubMed Central

    Chung, Man-Kyo; Cho, Yi Sul; Bae, Young Chul; Lee, Jongseok; Zhang, Xia; Ro, Jin Y.

    2014-01-01

    Background Although the efficacy of peripherally administered opioid has been demonstrated in preclinical and clinical studies, the underlying mechanisms of its anti-hyperalgesic effects are poorly understood. G protein-coupled inwardly rectifying potassium (GIRK) channels are linked to opioid receptors in the brain. However, the role of peripheral GIRK channels in analgesia induced by peripherally administered opioid, especially in trigeminal system, is not clear. Methods Expression of GIRK subunits in rat trigeminal ganglia (TG) was examined with RT-PCR, western blot and immunohistochemistry. Chemical profiles of GIRK expressing neurons in TG were further characterized. Behavioral and Fos experiments were performed to examine the functional involvement of GIRK channels in delta opioid receptor (DOR)-mediated anti-hyperalgesia under an acute myositis condition. Results TG expressed mRNA and proteins for GIRK1 and GIRK2 subunits. Majority of GIRK1- and GIRK2-expressing neurons were non-peptidergic afferents. Inhibition of peripheral GIRK using Tertiapin-Q (TPQ) attenuated anti-nociceptive effects of peripherally administered DOR agonist, DPDPE, on mechanical hypersensitivity in masseter muscle. Furthermore, TPQ attenuated the suppressive effects of peripheral DPDPE on neuronal activation in the subnucleus caudalis of the trigeminal nucleus (Vc) following masseteric injection of capsaicin. Conclusions Our data indicate that peripheral DOR agonist-induced suppression of mechanical hypersensitivity in the masseter muscle involves the activity of peripheral GIRK channels. These results could provide a rationale for developing a novel therapeutic approach using peripheral GIRK channel openers to mimic or supplement the effects of peripheral opioid agonist. PMID:23740773

  1. A Preliminary Analysis of the Relationship between Jaw-Muscle Architecture and Jaw-Muscle Electromyography during Chewing Across Primates

    PubMed Central

    Vinyard, Christopher J.; Taylor, Andrea B.

    2011-01-01

    The architectural arrangement of the fibers within a muscle has a significant impact on how a muscle functions. Recent work on primate jaw-muscle architecture demonstrates significant associations with dietary variation and feeding behaviors. In this study, the relationship between masseter and temporalis muscle architecture and jaw-muscle activity patterns is explored using Belanger's treeshrews and 11 primate species, including three genera of strepsirrhines (Lemur, Otolemur) and five genera of anthropoids (Aotus, Callithrix, Cebus, Macaca, Papio). Jaw-muscle weights, fiber lengths and physiologic cross-sectional areas (PCSA) were quantified for this preliminary analysis or collected from the literature and compared to published electromyographic (EMG) recordings from these muscles. Results indicate that masseter architecture is unrelated to the superficial masseter working-side/balancing-side (W/B) ratio across primate species. Alternatively, relative temporalis architecture is correlated with temporalis W/B ratios across primates. Specifically, relative temporalis PCSA is inversely related to the W/B ratio for the anterior temporalis indicating that as animals recruit a larger relative percentage of their balancing-side temporalis, they possess the ability to generate relatively larger amounts of force from these muscles. These findings support three broader conclusions. First, masseter muscle architecture may have experienced divergent evolution across different primate clades related to novel functional roles in different groups. Second, the temporalis may be functionally constrained (relative to the masseter) across primates in its functional role of creating vertical occlusal forces during chewing. Finally, the contrasting results for the masseter and temporalis suggest that the fiber architecture of these muscles has evolved as distinct functional units in primates. PMID:20235313

  2. Tooth Eruption Results from Bone Remodelling Driven by Bite Forces Sensed by Soft Tissue Dental Follicles: A Finite Element Analysis

    PubMed Central

    Sarrafpour, Babak; Swain, Michael; Li, Qing; Zoellner, Hans

    2013-01-01

    Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true ‘eruptive force’ is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, ‘biological response units’ in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of

  3. Influence of forward head posture on condylar position.

    PubMed

    Ohmure, H; Miyawaki, S; Nagata, J; Ikeda, K; Yamasaki, K; Al-Kalaly, A

    2008-11-01

    There are several reports suggesting that forward head posture is associated with temporomandibular disorders and restraint of mandibular growth, possibly due to mandibular displacement posteriorly. However, there have been few reports in which the condylar position was examined in forward head posture. The purpose of this study was to test the hypothesis that the condyle moves posteriorly in the forward head posture. The condylar position and electromyography from the masseter, temporal and digastric muscles were recorded on 15 healthy male adults at mandibular rest position in the natural head posture and deliberate forward head posture. The condylar position in the deliberate forward head posture was significantly more posterior than that in the natural head posture. The activity of the masseter and digastric muscles in the deliberate forward head posture was slightly increased. These results suggest that the condyle moves posteriorly in subjects with forward head posture. PMID:18808377

  4. Brain-derived neurotrophic factor enhances the excitability of small-diameter trigeminal ganglion neurons projecting to the trigeminal nucleus interpolaris/caudalis transition zone following masseter muscle inflammation

    PubMed Central

    2013-01-01

    Background The trigeminal subnuclei interpolaris/caudalis transition zones (Vi/Vc) play an important role in orofacial deep pain, however, the role of primary afferent projections to the Vi/Vc remains to be determined. This study investigated the functional significance of hyperalgesia to the brain-derived neurotrophic factor (BDNF)-tyrosine kinase B (trkB) signaling system in trigeminal ganglion (TRG) neurons projecting to the Vi/Vc transition zone following masseter muscle (MM) inflammation. Results The escape threshold from mechanical stimulation applied to skin above the inflamed MM was significantly lower than in naïve rats. Fluorogold (FG) labeling was used to identify the TRG neurons innervating the MM, while microbeads (MB) were used to label neurons projecting to the Vi/Vc region. FG/MB-labeled TRG neurons were immunoreactive (IR) for BDNF and trkB. The mean number of BDNF/trkB-IR small/medium-diameter TRG neurons was significantly higher in inflamed rats than in naïve rats. In whole-cell current-clamp experiments, the majority of dissociated small-diameter TRG neurons showed a depolarization response to BDNF that was associated with spike discharge, and the concentration of BDNF that evoked a depolarizing response was significantly lower in the inflamed rats. In addition, the relative number of BDNF-induced spikes during current injection was significantly higher in inflamed rats. The BDNF-induced changes in TRG neuron excitability was abolished by tyrosine kinase inhibitor, K252a. Conclusion The present study provided evidence that BDNF enhances the excitability of the small-diameter TRG neurons projecting onto the Vi/Vc following MM inflammation. These findings suggest that ganglionic BDNF-trkB signaling is a therapeutic target for the treatment of trigeminal inflammatory hyperalgesia. PMID:24073832

  5. Muscle fibre types in the suprahyoid muscles of the rat

    PubMed Central

    COBOS, A. R.; SEGADE, L. A. G.; FUENTES, I.

    2001-01-01

    Five muscle fibre types (I, IIc, IIa, IIx and IIb) were found in the suprahyoid muscles (mylohyoid, geniohyoid, and the anterior and posterior bellies of the digastric) of the rat using immuno and enzyme histochemical techniques. More than 90% of fibres in the muscles examined were fast contracting fibres (types IIa, IIx and IIb). The geniohyoid and the anterior belly of the digastric had the greatest number of IIb fibres, whilst the mylohyoid was almost exclusively formed by aerobic fibres. The posterior belly of the digastric contained a greater percentage of aerobic fibres (83.4%) than the anterior belly (67.8%). With the exception of the geniohyoid, the percentage of type I and IIc fibres, which have slow myosin heavy chain (MHCβ), was relatively high and greater than has been previously reported in the jaw-closing muscles of the rat, such as the superficial masseter. The geniohyoid and mylohyoid exhibited a mosaic fibre type distribution, without any apparent regionalisation, although in the later MHCβ-containing fibres (types I and IIc) were primarily located in the rostral 2/3 region. In contrast, the anterior and posterior bellies of the digastric revealed a clear regionalisation. In the anterior belly of the digastric 2 regions were observed: both a central region, which was almost exclusively formed by aerobic fibres and where all of the type I and IIc fibres were located, and a peripheral region, where type IIb fibres predominated. The posterior belly of the digastric showed a deep aerobic region which was greater in size and where type I and IIc fibres were confined, and a superficial region, where primarily type IIx and IIb fibres were observed. PMID:11322721

  6. Thermographic characterization of masticatory muscle regions in volunteers with and without myogenous temporomandibular disorder: preliminary results

    PubMed Central

    Brioschi, M L; Vardasca, R; Weber, M; Crosato, E M; Arita, E S

    2014-01-01

    Objectives: This study aims to conduct a non-invasive measurement of the cutaneous temperature of selected masticatory muscle regions of volunteers with and without myogenous temporomandibular disorder (TMD), using infrared thermography. Methods: 23 females (10 myogenous TMD volunteers and 13 controls) were recruited and studied. The temperature at the surface of the facial area over the anterior temporalis and masseter muscles was assessed by medical thermography, using regional lateral views and clinical examination. Results: The temperature levels measured at the masseter and anterior temporalis muscle regions in myogenous TMD volunteers (32.85 ± 0.85 and 34.37 ± 0.64 ºC, respectively) were significantly lower (p < 0.05) than those measured in controls (33.49 ± 0.92 and 34.78 ± 0.44 ºC, respectively). Medical infrared imaging indicated a mean difference of 1.4 ºC between the masseter and anterior temporalis regions. Analysis of the comparison between the absolute and normalized mean temperatures was performed using the pairwise comparison of receiver operating characteristic curves, and no statistically significant difference was observed (p > 0.05). The sensitivity and specificity of the thermographic assessment for the masseter region was of 70% and 73%, respectively and for the anterior temporalis region was of 80% and 62%, respectively. Conclusions: This method of evaluating masticatory muscle regions of this preliminary study seems to indicate that it can be used as an aid in complimentary diagnosing of TMDs. PMID:25144605

  7. Comparative jaw muscle anatomy in kangaroos, wallabies, and rat-kangaroos (marsupialia: macropodoidea).

    PubMed

    Warburton, Natalie Marina

    2009-06-01

    The jaw muscles were studied in seven genera of macropodoid marsupials with diets ranging from mainly fungi in Potorous to grass in Macropus. Relative size, attachments, and lamination within the jaw adductor muscles varied between macropodoid species. Among macropodine species, the jaw adductor muscle proportions vary with feeding type. The relative mass of the masseter is roughly consistent, but grazers and mixed-feeders (Macropus and Lagostrophus) had relatively larger medial pterygoids and smaller temporalis muscles than the browsers (Dendrolagus, Dorcopsulus, and Setonix). Grazing macropods show similar jaw muscle proportions to "ungulate-grinding" type placental mammals. The internal architecture of the jaw muscles also varies between grazing and browsing macropods, most significantly, the anatomy of the medial pterygoid muscle. Potoroines have distinctly different jaw muscle proportions to macropodines. The masseter muscle group, in particular, the superficial masseter is enlarged, while the temporalis group is relatively reduced. Lagostrophus fasciatus is anatomically distinct from other macropods with respect to its masticatory muscle anatomy, including enlarged superficial medial pterygoid and deep temporalis muscles, an anteriorly inflected masseteric process, and the shape of the mandibular condyle. The enlarged triangular pterygoid process of the sphenoid bone, in particular, is distinctive of Lagsotrophus. PMID:19462457

  8. Mastication and the Postorbital Ligament: Dynamic Strain in Soft Tissues

    PubMed Central

    Herring, Susan W.; Rafferty, Katherine L.; Liu, Zi Jun; Lemme, Michael

    2011-01-01

    Although the FEED database focuses on muscle activity patterns, it is equally suitable for other physiological recording and especially for synthesizing different types of information. The present contribution addresses the interaction between muscle activity and ligamentary stretch during mastication. The postorbital ligament is the thickened edge of a septum dividing the orbital contents from the temporal fossa and is continuous with the temporal fascia. As a tensile element, this fascial complex could support the zygomatic arch against the pull of the masseter muscle. An ossified postorbital bar has evolved repeatedly in mammals, enabling resistance to compression and shear in addition to tension. Although such ossification clearly reinforces the skull against muscle pull, the most accepted explanation is that it helps isolate the orbital contents from contractions of the temporalis muscle. However, it has never been demonstrated that the contraction of jaw muscles deforms the unossified ligament. We examined linear deformation of the postorbital ligament in minipigs, Sus scrofa, along with electromyography of the jaw muscles and an assessment of changes in pressure and shape in the temporalis. During chewing, the ligament elongated (average 0.9%, maximum 2.8%) in synchrony with the contraction of the elevator muscles of the jaw. Although the temporalis bulged outward and created substantial pressure against the braincase, the superficial fibers usually retracted caudally, away from the postorbital ligament. In anesthetized animals, stimulating either the temporalis or the masseter muscle in isolation usually elongated the ligament (average 0.4–0.7%). These results confirm that contraction of the masticatory muscles can potentially distort the orbital contents and further suggest that the postorbital ligament does function as a tension member resisting the pull of the masseter on the zygomatic arch. PMID:21593142

  9. An investigation of the simultaneously recorded occlusal contact and surface electromyographic activity of jaw-closing muscles for patients with temporomandibular disorders and a scissors-bite relationship.

    PubMed

    Qi, Kun; Guo, Shao-Xiong; Xu, YiFei; Deng, Qi; Liu, Lu; Li, Baoyong; Wang, Mei-Qing

    2016-06-01

    Surface electromyographic (SEMG) activity of the masseter and anterior temporalis (TA) muscles has been reported to be associated with occlusion and orofacial pain. However, our recent report did not reveal an association between the side of orofacial pain and the side showing higher or lower level of SEMG activity of masseter or TA. The present purpose was to re-test this association in patients who had unilateral scissors-bite relationship. Thirty-two unilateral scissors-bite femalepatients complaining of unilateral orofacial pain (n=15) or TMJ sounds (n=17) were enrolled to simultaneously record contacts, force distribution of occlusion, and SEMG activity of masseter and TA during centric maximal voluntary clenching (MVC). The results indicated that neither orofacial pain nor the TMJ sounds had an association with the masseter's SEMG values, while scissors-bite had (P<0.05). A lower SEMG value for masseter was found on the scissors-bite side where there was a smaller number of contacts and a lower biting force distribution (P<0.05). No such association was revealed in TA. In conclusion, in patients with unilateral TMD symptom(s) and scissors-bite, the jawclosing muscles' SEMG activity during centric MVC was associated with the scissors-bite rather than the symptoms of orofacial pain or TMJ sounds. PMID:27111032

  10. Electromyographic Evaluation of the Effect of Lined Dentures on Masticatory Muscle Activity in Edentulous Subjects

    PubMed Central

    Srivastava, Shitij; Gaur, Abhishek; Dupare, Arun; Rastogi, Shiksha; Kamatagi, Laxmikant

    2015-01-01

    Aim The purpose of this study was to examine changes in relative electromyographic (EMG) activities of temporal and masseter muscles after relining the dentures with silicone and acrylic-resin based denture liners. Materials and Methods Conventional complete dentures were fabricated for 20 edentulous patients. One month after completing adjustments of the dentures, electromyography of the masseter and temporalis muscle during maximum intercuspation was recorded. The dentures were then relined with a silicone denture liner and after an adaptation period of one month, were again subjected for electromyographic evaluation. Further, the dentures were relined with acrylic denture liner and subjected to electromyographic evaluation. Data was analysed using Statistical Package for Social Sciences (SPSS) version 15.0. Intergroup comparisons were done using ANOVA followed by post-hoc assessments using Tukey HSD test. Results Mean amplitude and duration with conventional dentures was found to be significantly lower as compared to silicone lined and acrylic lined dentures for all the comparisons. Statistically, no significant difference between silicone lined and acrylic lined dentures was observed for any of the comparisons. Conclusion Within the limitations of this experimental design, it was concluded that relining significantly increases electromyographic activity of the masseter and temporalis muscles. Thus, resulting in an improved biting force, chewing efficiency and masticatory performance. There were no significant differences between silicone and acrylic based denture liners for both electromyographic variables. PMID:26436054

  11. Effectiveness of botulinum toxin type A treatment of neck pain related to nocturnal bruxism: a case report

    PubMed Central

    Santamato, Andrea; Panza, Francesco; Di Venere, Daniela; Solfrizzi, Vincenzo; Frisardi, Vincenza; Ranieri, Maurizio; Fiore, Pietro

    2010-01-01

    Objective This case report describes a patient with nocturnal bruxism and related neck pain treated with botulinum toxin type A (BTX-A). Clinical Features The patient was a 27-year-old man with nocturnal bruxism and difficulty in active mouth opening and chewing and neck pain at rest. His numeric pain score was 7 of 10. Surface electromyography of the temporalis and masseter muscles showed typical signs of hyperactivity, characterized by compound muscle action potential amplitude alterations. Intervention and Outcome After clinical evaluation, he was treated with BTX-A to reduce masseter and temporalis muscle hyperactivity. After 3 days of treatment with BTX-A, with each masseter muscle injected with a dose of about 40 mouse units with a dilution of 1 mL and with temporal muscle bilaterally injected with 25 mouse units with the same dilution, a decrease in bruxism symptoms was reported. Neck pain also decreased after the first treatment (visual analog scale of 2/10) and then resolved completely. After 4 weeks, electromyography showed the reduction of muscle hyperactivity with a decrease in the amplitude of the motor action potential. The same reduction in signs and symptoms was still present at assessment 3 months posttreatment. Conclusion These findings suggest that BTX-A may be a therapeutic option for the treatment of bruxism and related disorders. PMID:22027036

  12. The effect of tongue position and resulting vertical dimension on masticatory muscle activity. A cross-sectional study.

    PubMed

    Valdés, C; Gutiérrez, M; Falace, D; Astaburuaga, F; Manns, A

    2013-09-01

    The purpose of this study was to: (a) compare the tonic electromyographic (EMG) activity of the temporalis and masseter muscles between two tongue positions, (b) compare the vertical dimension (VD) resulting from each tongue position and (c) determine the influence of the VD on the tonic EMG activity for each tongue position. Thirty-three healthy dental students with natural dentition and bilateral molar support, between the ages of 18 and 22 years, with no prior history of oro-facial injury, or current or past pain in the jaw, mouth, or tongue participated in the study. Tonic masseteric and temporalis EMG activities were recorded using surface electrodes. Subjects were instructed to passively place the tongue either on the anterior hard palate or in the floor of the mouth. At each tongue position, the resulting EMG and VD were recorded. No significant difference in EMG activity was found for either the masseter (P-value = 0·5376) or temporalis muscle (P-value = 0·7410), between the two tongue positions. However, there was a significant difference in the VD resulting from the two different tongue positions, being greater with the tongue placed in the floor of the mouth. There was no statistically significant correlation between VD and EMG activity for both tongue positions. In spite of the lack of difference in the effect of both tongue positions on the masseteric and temporalis EMG activity, an increment of the VD was registered for the floor of mouth-tongue position. However, VD was not correlated with EMG activity for both tongue positions. PMID:23855557

  13. Vascular lesion of the masseter presenting with phlebolith.

    PubMed

    Hessel, A C; Vora, N; Kountakis, S E; Chang, C Y

    1999-04-01

    When evaluating an intramuscular soft tissue mass, a large differential diagnosis including both benign and malignant lesions must be considered. Because the treatment of these masses can range from simple observation to radical surgical excision, a minimally invasive but accurate method of diagnosis is desired. The workup should include radiographic imaging. MRI is the modality of choice for differentiating soft tissue lesions, although CT may be helpful in identifying calcifications such as a phlebolith. Although usually unnecessary, a sialogram can verify that a calcification lies within or outside the salivary ductal system. In most cases a biopsy specimen is required to confirm the diagnosis. However, if the imaging studies show characteristics consistent with a vascular soft tissue mass, the finding of a phlebolith is pathognomonic for a benign vascular lesion. If such a lesion is not causing significant cosmetic or functional disability, it can be observed without the need for invasive biopsy or treatment. PMID:10187954

  14. [Electromyographic study on motor skill in chewing movement. A new concept on relating electromyographic analysis to chewing movements].

    PubMed

    Ishigaki, S; Tanaka, K; Nakatani, E; Yoshikawa, K; Omae, T; Inoue, S; Okuda, T; Akanishi, M; Maruyama, T

    1990-04-01

    This article was aimed to propose a new concept on evaluating electromyographic activities of masticatory muscles during chewing movements viewed from the standpoint of motor skill. Correlation coefficients between the ratio of lateral distance to ten vertical level set at 0.5 mm to 5.0 mm with 0.5 mm step from the end of closing phase and activities of bilateral masseter, anterior and posterior temporalis in each chewing stroke were evaluated using raisin, peanut, soft and hard testing gum in five subjects. Habitual chewing side always demonstrated less numbers of subjects who showed high correlation coefficients especially in the case of soft testing gum. PMID:2134796

  15. Morphology of the Jaw-Closing Musculature in the Common Wombat (Vombatus ursinus) Using Digital Dissection and Magnetic Resonance Imaging

    PubMed Central

    Sharp, Alana C.; Trusler, Peter W.

    2015-01-01

    Wombats are unique among marsupials in having one pair of upper incisors, and hypsodont molars for processing tough, abrasive vegetation. Of the three extant species, the most abundant, the common wombat (Vombatus ursinus), has had the least attention in terms of masticatory muscle morphology, and has never been thoroughly described. Using MRI and digital dissection to compliment traditional gross dissections, the major jaw adductor muscles, the masseter, temporalis and pterygoids, were described. The masseter and medial pterygoid muscles are greatly enlarged compared to other marsupials. This, in combination with the distinctive form and function of the dentition, most likely facilitates processing a tough, abrasive diet. The broad, flat skull and large masticatory muscles are well suited to generate a very high bite force. MRI scans allow more detail of the muscle morphology to be observed and the technique of digital dissections greatly enhances the knowledge obtained from gross dissections. PMID:25707001

  16. Morphology of the jaw-closing musculature in the common wombat (Vombatus ursinus) using digital dissection and magnetic resonance imaging.

    PubMed

    Sharp, Alana C; Trusler, Peter W

    2015-01-01

    Wombats are unique among marsupials in having one pair of upper incisors, and hypsodont molars for processing tough, abrasive vegetation. Of the three extant species, the most abundant, the common wombat (Vombatus ursinus), has had the least attention in terms of masticatory muscle morphology, and has never been thoroughly described. Using MRI and digital dissection to compliment traditional gross dissections, the major jaw adductor muscles, the masseter, temporalis and pterygoids, were described. The masseter and medial pterygoid muscles are greatly enlarged compared to other marsupials. This, in combination with the distinctive form and function of the dentition, most likely facilitates processing a tough, abrasive diet. The broad, flat skull and large masticatory muscles are well suited to generate a very high bite force. MRI scans allow more detail of the muscle morphology to be observed and the technique of digital dissections greatly enhances the knowledge obtained from gross dissections. PMID:25707001

  17. Can palpation-induced muscle pain pattern contribute to the differential diagnosis among temporomandibular disorders, primary headaches phenotypes and possible bruxism?

    PubMed Central

    Porporatti, André-Luís; Calderon, Patrícia-dos-Santos; Conti, Paulo-César-Rodrigues; Bonjardim, Leonardo-Rigoldi

    2016-01-01

    Background The evaluation of possible differences in the distribution or characteristics of palpation-induced pain in the masticatory muscles could be valuable in terms of diagnostic assessment. The aim of this study was to evaluate the impact of different combinations of anterior temporalis (AT) and masseter palpation-induced pain in the diagnostic of temporomandibular disorder (TMD), primary headaches and bruxism. Material and Methods A total of 1200 dental records of orofacial pain adult patients were analyzed. The outcomes were dichotomously classified (presence/absence) as following: a) AT and/or masseter palpation-induced pain; b) myogenous TMD; c) temporomandibular joint (TMJ) arthralgia (arthrogenous TMD); d) migraine; e) tension-type headache (TTH); f) self-reported bruxism. Binomial logistic regression model (α = 5%) was applied to the data considering the palpation-induced muscle pain as the dependent variable. Results Mean age (SD) were 35.7 years (13.4) for 635 included dental records (83% females). Myogenous and arthrogenous TMD, migraine, TTH and bruxism were mainly associated with, respectively, masseter palpation-induced pain (p<0.001 - OR=5.77, 95%CI 3.86-8.62), AT or masseter palpation-induced pain (p<0.001 - OR=2.39, 95%CI 1.57-3.63), bilateral AT palpation-induced pain (p<0.001 - OR=2.67, 95%CI 1.64-4.32), masseter and AT palpation-induced pain (p=0.009 - OR=1.62, 95%CI 1.12-2.33) and bilateral masseter palpation-induced pain (p=0.01 - OR=1.74, 95%CI 1.13-2.69). Conclusions Palpation-induced pain in the masticatory muscles may play a role in the differential diagnosis among painful TMD, primary headaches and bruxism. Key words:Diagnosis, temporomandibular joint disorders, migraine, tension-type headache, bruxism. PMID:26615507

  18. Electromyographic power spectrum of jaw muscles during clenching in unilateral temporomandibular joint osteoarthritis patients.

    PubMed

    Park, I H; McCall, W D; Chung, J W

    2012-09-01

    The relationship between temporomandibular joints (TMJ) osteoarthritis and masticatory muscle disorders is poorly understood. The data are sparse, the results are conflicting, and electromyographic (EMG) power spectrum analysis has not been used. The aims of this study were to compare the differences in EMG power spectrum during, and pressure pain thresholds (PPTs) before and after, sustained clenching in patients with unilateral TMJ osteoarthritis and healthy control subjects. Nineteen patients with unilateral TMJ osteoarthritis without masticatory muscle pain and 20 control subjects were evaluated. We measured EMG amplitudes at maximum voluntary contraction, median frequency from the EMG power spectrum during sustained clenching at 70% and PPTs before and after the clenching in both temporalis and masseter muscles. There were no significant differences in PPT decrease between muscles or between groups during sustained clenching. There were no significant differences in maximum voluntary contraction EMG activity ratios of affected to unaffected sides between groups, or of masseter to temporalis muscles between affected and unaffected side of patients with TMJ osteoarthritis. Median frequencies decreased from the beginning to the end of the sustained clench, and the interaction between group and clench was significant: the median frequency decrease was larger in the osteoarthritis group. Our results suggested that masticatory muscles of patients with unilateral TMJ osteoarthritis are more easily fatigued during sustained clenching than normal subjects. PMID:22672238

  19. The morphology of the mouse masticatory musculature.

    PubMed

    Baverstock, Hester; Jeffery, Nathan S; Cobb, Samuel N

    2013-07-01

    The mouse has been the dominant model organism in studies on the development, genetics and evolution of the mammalian skull and associated soft-tissue for decades. There is the potential to take advantage of this well studied model and the range of mutant, knockin and knockout organisms with diverse craniofacial phenotypes to investigate the functional significance of variation and the role of mechanical forces on the development of the integrated craniofacial skeleton and musculature by using computational mechanical modelling methods (e.g. finite element and multibody dynamic modelling). Currently, there are no detailed published data of the mouse masticatory musculature available. Here, using a combination of micro-dissection and non-invasive segmentation of iodine-enhanced micro-computed tomography, we document the anatomy, architecture and proportions of the mouse masticatory muscles. We report on the superficial masseter (muscle, tendon and pars reflecta), deep masseter, zygomaticomandibularis (anterior, posterior, infraorbital and tendinous parts), temporalis (lateral and medial parts), external and internal pterygoid muscles. Additionally, we report a lateral expansion of the attachment of the temporalis onto the zygomatic arch, which may play a role in stabilising this bone during downwards loading. The data presented in this paper now provide a detailed reference for phenotypic comparison in mouse models and allow the mouse to be used as a model organism in biomechanical and functional modelling and simulation studies of the craniofacial skeleton and particularly the masticatory system. PMID:23692055

  20. The morphology of the mouse masticatory musculature

    PubMed Central

    Baverstock, Hester; Jeffery, Nathan S; Cobb, Samuel N

    2013-01-01

    The mouse has been the dominant model organism in studies on the development, genetics and evolution of the mammalian skull and associated soft-tissue for decades. There is the potential to take advantage of this well studied model and the range of mutant, knockin and knockout organisms with diverse craniofacial phenotypes to investigate the functional significance of variation and the role of mechanical forces on the development of the integrated craniofacial skeleton and musculature by using computational mechanical modelling methods (e.g. finite element and multibody dynamic modelling). Currently, there are no detailed published data of the mouse masticatory musculature available. Here, using a combination of micro-dissection and non-invasive segmentation of iodine-enhanced micro-computed tomography, we document the anatomy, architecture and proportions of the mouse masticatory muscles. We report on the superficial masseter (muscle, tendon and pars reflecta), deep masseter, zygomaticomandibularis (anterior, posterior, infraorbital and tendinous parts), temporalis (lateral and medial parts), external and internal pterygoid muscles. Additionally, we report a lateral expansion of the attachment of the temporalis onto the zygomatic arch, which may play a role in stabilising this bone during downwards loading. The data presented in this paper now provide a detailed reference for phenotypic comparison in mouse models and allow the mouse to be used as a model organism in biomechanical and functional modelling and simulation studies of the craniofacial skeleton and particularly the masticatory system. PMID:23692055

  1. Jaw muscles of New World squirrels.

    PubMed

    Ball, S S; Roth, V L

    1995-06-01

    The jaw, suprahyoid, and extrinsic tongue muscles are described for eight species of New World squirrels, spanning more than an order of magnitude in body mass. Anatomical differences are discussed in the light of body size, natural history, and phylogeny. The relative sizes of different muscles, their orientations, and the shapes and positions of their areas of attachment vary but show few trends in relation to body size. The anatomical differences are likewise not readily explained by the mechanical requirements of the animals' diets, which are similar. The most marked anatomical differences occur in Sciurillus (the pygmy tree squirrel), as well as those genera--Glaucomys (the flying squirrel) and Tamias (the chipmunk)--that are taxonomically most distinct from the tree squirrels. Sciurillus is noteworthy for its unusually small temporalis and an anterior deep masseter that is oriented to assist in retraction of the jaw. Tamias has a more vertically oriented temporalis and greater inclination in the anterior masseter muscles than the other squirrels, features that may be associated with its large diastema and relatively posteriorly situated cheek teeth, which in turn may relate to its having cheek pouches. Our results form a valuable database of information to be used in further studies of functional morphology and phylogeny. PMID:7541086

  2. Effect of β-hydroxy-β-methylbutyrate in masticatory muscles of rats.

    PubMed

    Daré, Leticia R; Dias, Daniel V; Rosa Junior, Geraldo M; Bueno, Cleuber R S; Buchaim, Rogerio L; Rodrigues, Antonio de C; Andreo, Jesus C

    2015-01-01

    The aim of this research was to examine the influence of β-hydroxy-β-methylbutyrate (HMB) on changes in the profile of muscle fibers, whether these alterations were similar between the elevator and depressor muscles of the jaw, and whether the effects would be similar in male and female animals. Fifty-eight rats aged 60 days (29 animals of each gender) were divided into four groups: the initial control group (ICG) was sacrificed at the beginning of the experiment; the placebo control group (PCG) received saline and was fed ad libitum; the experimental group (EG) received 0.3 g kg(-1) of HMB daily for 4 weeks by gavage as well as the same amount of food consumed by the PCG in the previous day; and the experimental ad libitum group (EAG) received the same dose of the supplement along with food ad libitum. Samples included the digastric and masseter muscles for the histoenzymological analysis. Data were subjected to statistical analysis with a significance level of P < 0.05. Use of HMB caused a decrease in the percentage of fast twitch glycolytic (FG) fibers and an increase in fast twitch oxidative glycolytic (FOG) fibers in males in both experimental groups (EG and EAG). However, it produced no increase in the muscle fiber area, in either gender, in the masseter muscle. In the digastric muscle, the HMB did not change the frequency or the area of any muscle fiber types in either gender. Our data suggest that the use of HMB caused small changes in the enzymological profile of fibers of the mastication muscles; the changes were different in the elevator and depressor muscles of the jaw and the results were different depending on gender. PMID:25400135

  3. Botulinum toxin in masticatory muscles of the adult rat induces bone loss at the condyle and alveolar regions of the mandible associated with a bone proliferation at a muscle enthesis.

    PubMed

    Kün-Darbois, Jean-Daniel; Libouban, Hélène; Chappard, Daniel

    2015-08-01

    In man, botulinum toxin type A (BTX) is injected in masticatory muscles for several indications such as trismus, bruxism, or masseter hypertrophy. Bone changes in the mandible following BTX injections in adult animal have therefore became a subject of interest. The aim of this study was to analyze condylar and alveolar bone changes following BTX unilateral injections in masseter and temporal muscles in adult rats. Mature male rats (n = 15) were randomized into 2 groups: control (CTRL; n = 6) and BTX group (n= 9). Rats of the BTX group received a single injection of BTX into right masseter and temporal muscles. Rats of the CTRL group were similarly injected with saline solution. Rats were sacrificed 4 weeks after injections. Masticatory muscles examination and microcomputed tomography (microCT) were performed. A significant difference of weight was found between the 2 groups at weeks 2, 3 and 4 (p < 0.05). Atrophy of the right masseter and temporal muscles was observed in all BTX rats. MicroCT analysis showed significant bone loss in the right alveolar and condylar areas in BTX rats. Decrease in bone volume reached -20% for right alveolar bone and -35% for right condylar bone. A hypertrophic bone metaplasia at the digastric muscle enthesis was found on every right hemimandible in the BTX group and none in the CTRL group. BTX injection in masticatory muscles leads to a significant and major mandible bone loss. These alterations can represent a risk factor for fractures in human. The occurrence of a hypertrophic bone metaplasia at the Mus Digastricus enthesis may constitute an etiological factor for tori. PMID:25857689

  4. Effect of Postnatal Myostatin Inhibition on Bite Mechanics in Mice.

    PubMed

    Williams, Susan H; Lozier, Nicholas R; Montuelle, Stéphane J; de Lacalle, Sonsoles

    2015-01-01

    As a negative regulator of muscle size, myostatin (Mstn) impacts the force-production capabilities of skeletal muscles. In the masticatory system, measures of temporalis-stimulated bite forces in constitutive myostatin KOs suggest an absolute, but not relative, increase in jaw-muscle force. Here, we assess the phenotypic and physiologic impact of postnatal myostatin inhibition on bite mechanics using an inducible conditional KO mouse in which myostatin is inhibited with doxycycline (DOX). Given the increased control over the timing of gene inactivation in this model, it may be more clinically-relevant for developing interventions for age-associated changes in the musculoskeletal system. DOX was administered for 12 weeks starting at age 4 months, during which time food intake was monitored. Sex, age and strain-matched controls were given the same food without DOX. Bite forces were recorded just prior to euthanasia after which muscle and skeletal data were collected. Food intake did not differ between control or DOX animals within each sex. DOX males were significantly larger and had significantly larger masseters than controls, but DOX and control females did not differ. Although there was a tendency towards higher absolute bite forces in DOX animals, this was not significant, and bite forces normalized to masseter mass did not differ. Mechanical advantage for incisor biting increased in the DOX group due to longer masseter moment arms, likely due to a more anteriorly-placed masseter insertion. Despite only a moderate increase in bite force in DOX males and none in DOX females, the increase in masseter mass in males indicates a potentially positive impact on jaw muscles. Our data suggest a sexual dimorphism in the role of mstn, and as such investigations into the sex-specific outcomes is warranted. PMID:26252892

  5. Effect of Postnatal Myostatin Inhibition on Bite Mechanics in Mice

    PubMed Central

    Williams, Susan H.; Lozier, Nicholas R.; Montuelle, Stéphane J.; de Lacalle, Sonsoles

    2015-01-01

    As a negative regulator of muscle size, myostatin (Mstn) impacts the force-production capabilities of skeletal muscles. In the masticatory system, measures of temporalis-stimulated bite forces in constitutive myostatin KOs suggest an absolute, but not relative, increase in jaw-muscle force. Here, we assess the phenotypic and physiologic impact of postnatal myostatin inhibition on bite mechanics using an inducible conditional KO mouse in which myostatin is inhibited with doxycycline (DOX). Given the increased control over the timing of gene inactivation in this model, it may be more clinically-relevant for developing interventions for age-associated changes in the musculoskeletal system. DOX was administered for 12 weeks starting at age 4 months, during which time food intake was monitored. Sex, age and strain-matched controls were given the same food without DOX. Bite forces were recorded just prior to euthanasia after which muscle and skeletal data were collected. Food intake did not differ between control or DOX animals within each sex. DOX males were significantly larger and had significantly larger masseters than controls, but DOX and control females did not differ. Although there was a tendency towards higher absolute bite forces in DOX animals, this was not significant, and bite forces normalized to masseter mass did not differ. Mechanical advantage for incisor biting increased in the DOX group due to longer masseter moment arms, likely due to a more anteriorly-placed masseter insertion. Despite only a moderate increase in bite force in DOX males and none in DOX females, the increase in masseter mass in males indicates a potentially positive impact on jaw muscles. Our data suggest a sexual dimorphism in the role of mstn, and as such investigations into the sex-specific outcomes is warranted. PMID:26252892

  6. Excitation of a single atom with a temporaly shaped light pulses

    NASA Astrophysics Data System (ADS)

    Maslennikov, Gleb; Aljunid, Syed; Hoang Lan, Dao; Durak, Kadir; Leong, Victor; Kurtsiefer, Christian

    2012-06-01

    We investigate the interaction between a single atom and coherent optical pulses with a controlled temporal envelope. By switching the temporal shape from rising exponential to square profile, we show that the rising exponential envelope leads to higher excitation probability using lower photon number in a pulse. The atomic transition saturates for 100 photons in a pulse. Rabi oscillations with 100,Hz frequency are visible in detected fluorescence for excitations powers of 1300 photons in a 15,s pulse. A possibility to excite the atom with pulses in a Fock states is discussed and the theoretical treatment is presented. [4pt] [1] Yimin Wang et al., Phys. Rev. A. 83 063842 (2011)[0pt] [2] M. Stobinska et al., EPL 86 14007 (2009)[0pt] [3] I. Gerhardt et al., Phys. Rev. A 79 011402(R) (2009)

  7. Campylorrhinus lateralis, Bilateral microphthalmia and odontoma temporalis in an Oldenburg Foal.

    PubMed

    Casteleyn, C; Cornillie, P; Tüllmann, V; Van Cruchten, S; Van Ginneken, C

    2016-04-01

    An Oldenburg colt with wry nose was autopsied after having lived for only 30 min. It presented cyanotic oral mucosae, underdeveloped eyes and a right-sided temporal osseous mass. The applicable nomenclature for the defects is discussed, and the potential etiopathogenesis is explored by describing the normal embryonic development of the affected body parts. PMID:26825866

  8. Digital dissection of the masticatory muscles of the naked mole-rat, Heterocephalus glaber (Mammalia, Rodentia)

    PubMed Central

    Faulkes, Chris G.

    2014-01-01

    The naked mole-rat, Heterocephalus glaber, of the family Bathyergidae is a subterranean rodent that feeds on underground roots and tubers and digs extensive tunnel systems with its incisors. It is a highly unusual mammal with regard to its social structure, longevity, pain insensitivity and cancer resistance, all of which have made it the subject of a great deal of research in recent years. Yet, much of the basic anatomy of this species remains undocumented. In this paper, we describe the morphology of the jaw-closing musculature of the naked mole-rat, as revealed by contrast-enhanced micro-computed tomography. This technique uses an iodine stain to enable the imaging of soft tissues with microCT. The iodine-enhanced scans were used to create 3D reconstructions of the naked mole-rat masticatory muscles from which muscle masses were calculated. The jaw-closing musculature of Heterocephalus glaber is relatively very large compared to other rodents and is dominated by the superficial masseter, the deep masseter and the temporalis. The temporalis in particular is large for a rodent, covering the entirety of the braincase and much of the rear part of the orbit. The morphology of the masseter complex described here differs from two other published descriptions of bathyergid masticatory muscles, but is more similar to the arrangement seen in other rodent families. The zygomaticomandibularis (ZM) muscle does not protrude through the infraorbital foramen on to the rostrum and thus the naked mole-rat should be considered protrogomorphous rather than hystricomorphous, and the morphology is consistent with secondarily lost hystricomorphy as has been previously suggested for Bathyergidae. Overall, the morphology of the masticatory musculature indicates a species with a high bite force and a wide gape–both important adaptations for a life dominated by digging with the incisors. PMID:25024917

  9. Electromyographic standardized indices in healthy Brazilian young adults and data reproducibility.

    PubMed

    De Felício, C M; Sidequersky, F V; Tartaglia, G M; Sforza, C

    2009-08-01

    The determination of normal parameters is an important procedure in the evaluation of the stomatognathic system. We used the surface electromyography standardization protocol described by Ferrario et al. (J Oral Rehabil. 2000;27:33-40, 2006;33:341) to determine reference values of the electromyographic standardized indices for the assessment of muscular symmetry (left and right side, percentage overlapping coefficient, POC), potential lateral displacing components (unbalanced contractile activities of contralateral masseter and temporalis muscles, TC), relative activity (most prevalent pair of masticatory muscles, ATTIV) and total activity (integrated areas of the electromyographic potentials over time, IMPACT) in healthy Brazilian young adults, and the relevant data reproducibility. Electromyography of the right and left masseter and temporalis muscles was performed during maximum teeth clenching in 20 healthy subjects (10 women and 10 men, mean age 23 years, s.d. 3), free from periodontal problems, temporomandibular disorders, oro-facial myofunctional disorder, and with full permanent dentition (28 teeth at least). Data reproducibility was computed for 75% of the sample. The values obtained were POC Temporal (88.11 +/- 1.45%), POC masseter (87.11 +/- 1.60%), TC (8.79 +/- 1.20%), ATTIV (-0.33 +/- 9.65%) and IMPACT (110.40 +/- 23.69 microV/microV.s %). There were no statistical differences between test and retest values (P > 0.05). The Technical Errors of Measurement (TEM) for 50% of subjects assessed during the same session were 1.5, 1.39, 1.06, 3.83 and 10.04. For 25% of the subjects assessed after a 6-month interval, the TEM were 0.80, 1.03, 0.73, 12.70 and 19.10. For all indices, there was good reproducibility. These electromyographic indices could be used in the assessment of patients with stomatognathic dysfunction. PMID:19548958

  10. Cranial functional morphology of fossil dogs and adaptation for durophagy in Borophagus and Epicyon (Carnivora, Mammalia).

    PubMed

    Tseng, Zhijie Jack; Wang, Xiaoming

    2010-11-01

    Morphological specialization is a complex interplay of adaptation and constraint, as similarly specialized features often evolve convergently in unrelated species, indicating that there are universally adaptive aspects to these morphologies. The evolutionary history of carnivores offers outstanding examples of convergent specialization. Among larger predators, borophagine canids were highly abundant during the tertiary of North America and are regarded as the ecological vicars of Afro-Eurasian hyenas. Borophaginae is an extinct group of 60+ species, the largest forms evolving robust skulls with prominently domed foreheads, short snouts, and hypertrophied fourth premolars. These specializations have been speculated to enhance bone cracking. To test the extent that the skulls of derived borophagines were adapted for producing large bite forces and withstanding the mechanical stresses associated with bone cracking relative to their nonrobust sister clades, we manipulated muscle forces in models of six canid skulls and analyzed their mechanical response using 3D finite element analysis. Performance measures of bite force production efficiency and deformation minimization showed that skulls of derived borophagines Borophagus secundus and Epicyon haydeni are particularly strong in the frontal region; maximum stresses are lower and more evenly distributed over the skull than in other canids. Frontal strength is potentially coupled with a temporalis-driven bite to minimize cranial stress during biting in the two derived genera, as tensile stress incurred by contracting temporalis muscles is dissipated rostro-ventrally across the forehead and face. Comparison of estimated masticatory muscle cross section areas suggests that the temporalis-masseter ratio is not strongly associated with morphological adaptations for bone cracking in Borophagus and Epicyon; larger body size may explain relatively larger temporalis muscles in the latter. When compared with previous studies, the

  11. Masticatory muscle architecture in the Laotian rock rat Laonastes aenigmamus (Mammalia, Rodentia): new insights into the evolution of hystricognathy

    PubMed Central

    Hautier, Lionel; Saksiri, Soonchan

    2009-01-01

    We present the first descriptive comparison of the skull, mandible and jaw muscles of the recently recovered Laotian rock rat Laonastes aenigmamus. The gross anatomy of five specimens captured in Laos and internal architecture of the jaw musculature were studied using dissections. The following muscles are described: temporal, masseter, pterygoids, digastric, mylohyoid, geniohyoid and transverse mandibular. The description of the masticatory apparatus of L. aenigmamus offers a rare opportunity to assess the order of establishment of the morphological characters during the evolution of Ctenohystrica. Striking convergences have occurred during the evolution of Diatomyidae and L. aenigmamus presents a unique combination of myological features that corresponds to a mixture of sciurognathous and hystricognathous characters. If L. aenigmamus is a sciurognathous rodent, we have to assume that it independently acquired a pars reflexa of the superficial masseter. We show for the first time that the development of this pars reflexa has occurred several times during the evolution of Ctenohystrica and can no longer be considered a synapomorphic feature of ‘Hystricognathi’. These results bring new insights into the evolution of hystricognathy and have profound implications for the interpretation of the fossil record of early hystricognath rodents. PMID:19694873

  12. Effects of cervical mobilization and exercise on pain, movement and function in subjects with temporomandibular disorders: a single group pre-post test

    PubMed Central

    CALIXTRE, Letícia Bojikian; GRÜNINGER, Bruno Leonardo da Silva; HAIK, Melina Nevoeiro; ALBURQUERQUE-SENDÍN, Francisco; OLIVEIRA, Ana Beatriz

    2016-01-01

    ABSTRACT Objective To investigate the effect of a rehabilitation program based on cervical mobilization and exercise on clinical signs and mandibular function in subjects with temporomandibular disorder (TMD). Material and Methods: Single-group pre-post test, with baseline comparison. Subjects Twelve women (22.08±2.23 years) with myofascial pain and mixed TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders. Outcome measures Subjects were evaluated three times: twice before (baseline phase) and once after intervention. Self-reported pain, jaw function [according to the Mandibular Functional Impairment Questionnaire (MFIQ)], pain-free maximum mouth opening (MMO), and pressure pain thresholds (PPTs) of both masseter and temporalis muscles were obtained. Baseline and post-intervention differences were investigated, and effect size was estimated through Cohen’s d coefficient. Results Jaw function improved 7 points on the scale after the intervention (P=0.019), and self-reported pain was significantly reduced (P=0.009). Pain-free MMO varied from 32.3±8.8 mm to 38±8.8 mm and showed significant improvement (P=0.017) with moderate effect size when compared to the baseline phase. PPT also increased with moderate effect size, and subjects had the baseline values changed from 1.23±0.2 kg/cm2 to 1.4±0.2 kg/cm2 in the left masseter (P=0.03), from 1.31±0.28 kg/cm2 to 1.51±0.2 kg/cm2 in the right masseter (P>0.05), from 1.32±0.2 kg/cm2 to 1.46±0.2 kg/cm2 in the left temporalis (P=0.047), and from 1.4±0.2 kg/cm2 to 1.67±0.3 kg/cm2 in the right temporalis (P=0.06). Conclusions The protocol caused significant changes in pain-free MMO, self-reported pain, and functionality of the stomatognathic system in subjects with myofascial TMD, regardless of joint involvement. Even though these differences are statistically significant, their clinical relevance is still questionable. PMID:27383698

  13. Feeding mechanics and dietary implications in the fossil sloth Neocnus (Mammalia: Xenarthra: Megalonychidae) from Haiti.

    PubMed

    McAfee, Robert K

    2011-10-01

    Haitian species of the extinct ground sloth genus Neocnus (Mammalia: Pilosa: Megalonychidae) have previously been hypothesized to have a much reduced jugal bone and a correspondingly reduced masseter musculature but a paucity of specimens has prevented further investigation of this hypothesis. Recent discovery of jugal bones belonging to Haitian specimens of Neocnus within the University of Florida Museum collections enables the element to be more accurately described. The discovery also makes it possible to explore mastication in these sloths. Osteological characters related to feeding were examined, along with comparative estimations of bite force with the extant tree sloths, Bradypus and Choloepus, and their known dietary habits as a means to infer aspects of the paleodiet of Neocnus. There is a significant difference in moment arm calculations for m. masseter between predicted and actual jugals, but the overall significance for bite force is lost and hampered by small sample size. Neocnus demonstrates a variety of characters that are similar to those of Bradypus and not to Choloepus, which is a close phylogenetic relative. The masticatory musculature of Neocnus enabled a chewing cycle emphasizing a grinding combination of mesiodistal and linguobuccal movements of the molariform dentition. The orientations of m. masseter and m. temporalis are estimated to produce relatively high bite force ratios that imply a masticatory system with stronger versus faster components. Because of the similarity of bite forces and jaw mechanics to those of Bradypus, in addition to a number of osteological adaptations indicative of herbivorous grazers (elevated mandibular condyle, large and complex masseter, and robust angular process), the Haitian forms of Neocnus are considered to have been selective feeders with a folivorous diet. PMID:21638306

  14. Reviewing the morphology of the jaw-closing musculature in squirrels, rats, and guinea pigs with contrast-enhanced microCT.

    PubMed

    Cox, Philip G; Jeffery, Nathan

    2011-06-01

    Rodents are defined by their unique masticatory apparatus and are frequently separated into three nonmonophyletic groups--sciuromorphs, hystricomorphs, and myomorphs--based on the morphology of their masticatory muscles. Despite several comprehensive dissections in previous work, inconsistencies persist as to the exact morphology of the rodent jaw-closing musculature, particularly, the masseter. Here, we review the literature and document for the first time the muscle architecture noninvasively and in 3D by using iodine-enhanced microCT. Observations and measurements were recorded with reference to images of three individuals, each belonging to one of the three muscle morphotypes (squirrel, guinea pig, and rat). Results revealed an enlarged superficial masseter muscle in the guinea pig compared with the rat and squirrel, but a reduced deep masseter (possibly indicating reduced efficiency at the incisors). The deep masseter had expanded forward to take an origin on the rostrum and was also separated into anterior and posterior parts in the rat and squirrel. The zygomaticomandibularis muscle was split into anterior and posterior parts in all the three specimens by the masseteric nerve, and in the rat and guinea pig had an additional rostral expansion through the infraorbital foramen. The temporalis muscle was found to be considerably larger in the rat, and its separation into anterior and posterior parts was only evident in the rat and squirrel. The pterygoid muscles were broadly similar in all three specimens, although the internal pterygoid was somewhat enlarged in the guinea pig implying greater lateral movement of the mandible during chewing in this species. PMID:21538924

  15. A Case of Bruxism-Induced Otalgia

    PubMed Central

    2016-01-01

    Here, the author presents a case of bruxism-induced otalgia in a 29-year-old female patient. The pain was sharp and penetrating in character. It was usually worse in the morning and frequently radiated to the right temporal area. She had received unsuccessful medical treatments for migraine headache. The otoendoscopic examination revealed a normal tympanic membrane. A thorough inspection of her teeth revealed excessive wear on the incisal edges, and the cause of her otalgia was identified as bruxism-related temporomandibular joint disorder. After the use of an occlusal splint and repeated botulinum toxin injections in the masseter and anterior temporalis muscles, along with good sleep hygiene, she experienced significant relief of pain and symptoms. The author suggests that multidisciplinary cooperation between ENT clinicians and dentists is necessary for the quick and accurate diagnosis and treatment of bruxism and the consequential referred otalgia. PMID:27626088

  16. An intriguing case of locked jaw secondary to melioidosis.

    PubMed

    Vaid, Tejasvini; Rao, Karthik; Hande, Handattu Manjunath

    2015-01-01

    A 56-year-old woman presented with fever, pain and restriction of movement of the right temporomandibular joint. She was premorbidly diagnosed to have type 2 diabetes mellitus and rheumatoid arthritis. Local examination revealed a poorly demarcated severely tender, erythematous swelling in the right preauricular region. All haematological and biochemical investigations were within normal limits. MRI of the neck revealed the presence of a masticator space infection with intramuscular abscess involving the masseter and the temporalis muscles along with intracranial extension. Osteomyelitic changes were detected in the right mandibular condyle, temporal bone and in the temporomandibular joint. Melioidosis was suspected due to this unique clinical presentation of an abscess at an unusual and atypical site. Blood cultures identified the Gram-negative bacilli Burkholderia pseudomallei, which established the diagnosis of Melioidosis. Remarkable improvement was attained with antibiotics meropenem and cotrimoxazole, deferring the need for any surgical intervention. PMID:26628312

  17. Trismus and diffuse polymyalgia: an unusual presentation of recurrent metastatic ovarian cancer.

    PubMed

    Benjamin, Ramsis; Zhai, Jing; Morgan, Robert; Prakash, Neal

    2014-01-01

    A 22-year-old woman first presented in 2009 with abdominal distention. The diagnosis of stage IA right ovarian tumour was made by fertility-sparing surgery. In the subsequent years, the involvement of the left ovary and metastasis to the lungs prompted further surgical intervention and chemotherapy. By 2013, she experienced insidious, debilitating and diffuse musculoskeletal pain with trismus. Polymyositis or diffuse radiculitis was suspected. Imaging studies identified enhancing lesions in the thigh musculature, temporalis, parotid gland, pterygoid, masseter, tongue, cerebellum and leptomeninges. Biopsy of one of the thigh lesions confirmed the diagnosis of mucinous adenocarcinoma. She succumbed to the disease in November 2013. This case illustrates the aggressive nature of mucinous epithelial ovarian cancer and its resilience to conventional chemotherapy. On account of its high death rate, it is recommended that the epithelial-mesenchymal transition be researched and early therapy targeted at the k-ras oncogene initiated in spite of the tumour's lower initial staging. PMID:24835804

  18. Treatment of displaced mandibular condylar fracture with botulinum toxin A.

    PubMed

    Akbay, Ercan; Cevik, Cengiz; Damlar, Ibrahim; Altan, Ahmet

    2014-04-01

    The aim of this case report is to discuss the effect on condylar reduction of botulinum toxin A treatment used in a child with displaced fracture at condylar neck of mandible. A 3-years old boy was admitted to our clinic for incomplete fracture of mandibular symphysis and displaced condylar fracture at the left side. An asymmetrical occlusal splint with intermaxillary fixation was used instead of open reduction and internal fixation because of incomplete fracture of symphysis and possible complications of condyle surgery. However, it was observed that condylar angulation persisted despite this procedure. Thus, botulinum toxin A was administered to masseter, temporalis and pterygoideus medialis muscles. At the end of first month, it was seen that mandibular condyle was almost completely recovered and that fusion was achieved. In conclusion, Botulinum A toxin injection aiming the suppression of masticatory muscle strength facilitates the reduction in the conservative management of displaced condyle in pediatric patients. PMID:24156980

  19. The measurement and facilitation of cooperative task performance. [reactions of humans to stress exposure

    NASA Technical Reports Server (NTRS)

    Hutchinson, R. R.

    1975-01-01

    Experiments were conducted to determine under what conditions jaw clenching will occur in humans as a response to stress exposure. The method for measuring reactions to stress involves a series of electrical recordings of the masseter and temporalis muscles. A high fixed-ratio response requirement in the first series of experiments shows that jaw clenching in humans occurs in situations analogous to those which produce biting in infrahuman subjects. In the second series, reduction in the amounts of money recieved by subjects is shown to cause increases in the jaw clench response and other negative effect motor behaviors. The third series demonstrates that perception of more favorable conditions existing for another person can increase anger and hostility in the subject.

  20. Hemimasticatory Spasm: Report of a Case and Review of the Literature†

    PubMed Central

    Christie, Corina; Rodríguez-Quiroga, Sergio Alejandro; Arakaki, Tomoko; Rey, Roberto Daniel; Garretto, Nélida Susana

    2014-01-01

    Background Hemimasticatory spasm is a very rare movement disorder characterized by unilateral, involuntary, paroxysmal contractions of the jaw-closing muscles, causing clinically brief twitches and/or spasms. Case Report A 62-year-old female consulted us with a 30-year history of unusual involuntary twitches in the preauricular region and spasms that hampered jaw opening. During these spasms, she could not open her mouth. On physical examination, we also observed hypertrophy of the masseter and temporalis muscles, which can be features of hemimasticatory spasm. She was treated with botulinum toxin type A, with excellent response. Here, we present her case and review the literature. Discussion Hemimasticatory spasm is a rare movement disorder. Given the excellent response to botulinum toxin type A treatment, it should be considered within the spectrum of facial spasms. PMID:24757582

  1. Trismus and diffuse polymyalgia: an unusual presentation of recurrent metastatic ovarian cancer

    PubMed Central

    Benjamin, Ramsis; Zhai, Jing; Morgan, Robert; Prakash, Neal

    2014-01-01

    A 22-year-old woman first presented in 2009 with abdominal distention. The diagnosis of stage IA right ovarian tumour was made by fertility-sparing surgery. In the subsequent years, the involvement of the left ovary and metastasis to the lungs prompted further surgical intervention and chemotherapy. By 2013, she experienced insidious, debilitating and diffuse musculoskeletal pain with trismus. Polymyositis or diffuse radiculitis was suspected. Imaging studies identified enhancing lesions in the thigh musculature, temporalis, parotid gland, pterygoid, masseter, tongue, cerebellum and leptomeninges. Biopsy of one of the thigh lesions confirmed the diagnosis of mucinous adenocarcinoma. She succumbed to the disease in November 2013. This case illustrates the aggressive nature of mucinous epithelial ovarian cancer and its resilience to conventional chemotherapy. On account of its high death rate, it is recommended that the epithelial–mesenchymal transition be researched and early therapy targeted at the k-ras oncogene initiated in spite of the tumour's lower initial staging. PMID:24835804

  2. A Case of Bruxism-Induced Otalgia.

    PubMed

    Kim, Se-Hyung

    2016-09-01

    Here, the author presents a case of bruxism-induced otalgia in a 29-year-old female patient. The pain was sharp and penetrating in character. It was usually worse in the morning and frequently radiated to the right temporal area. She had received unsuccessful medical treatments for migraine headache. The otoendoscopic examination revealed a normal tympanic membrane. A thorough inspection of her teeth revealed excessive wear on the incisal edges, and the cause of her otalgia was identified as bruxism-related temporomandibular joint disorder. After the use of an occlusal splint and repeated botulinum toxin injections in the masseter and anterior temporalis muscles, along with good sleep hygiene, she experienced significant relief of pain and symptoms. The author suggests that multidisciplinary cooperation between ENT clinicians and dentists is necessary for the quick and accurate diagnosis and treatment of bruxism and the consequential referred otalgia. PMID:27626088

  3. Endocranial and masticatory muscle volumes in myostatin-deficient mice

    PubMed Central

    Jeffery, Nathan; Mendias, Christopher

    2014-01-01

    Structural and functional trade-offs are integral to the evolution of the mammalian skull and its development. This paper examines the potential for enlargement of the masticatory musculature to limit the size of the endocranial cavity by studying a myostatin-deficient mouse model of hypermuscularity (MSTN−/−). The study tests the null prediction that the larger MSTN−/− mice have larger brains compared with wild-type (WT) mice in order to service the larger muscles. Eleven post-mortem MSTN−/− mice and 12 WT mice were imaged at high resolution using contrast enhanced micro-CT. Masticatory muscle volumes (temporalis, masseter, internal and external pterygoids) and endocranial volumes were measured on the basis of two-dimensional manual tracings and the Cavalieri principle. Volumes were compared using Kruskal–Wallis and Student's t-tests. Results showed that the masticatory muscles of the MSTN−/− mice were significantly larger than in the WT mice. Increases were in the region of 17–36% depending on the muscle. Muscles increased in proportion to each other, maintaining percentages in the region of 5, 10, 21 and 62% of total muscle volume for the external ptyergoid, internal pterygoid, temporalis and masseter, respectively. Kruskal–Wallis and t-tests demonstrated that the endocranial volume was significantly larger in the WT mice, approximately 16% larger on average than that seen in the MSTN−/− mice. This comparative reduction of MSTN−/− endocranial size could not be explained in terms of observer bias, ageing, sexual dimorphism or body size scaling. That the results showed a reduction of brain size associated with an increase of muscle size falsifies the null prediction and lends tentative support to the view that the musculature influences brain growth. It remains to be determined whether the observed effect is primarily physical, nutritional, metabolic or molecular in nature. PMID:26064569

  4. Modeling of muscle forces in humans with and without temporomandibular joint disorders

    PubMed Central

    Iwasaki, LR; Liu, H; Gonzalez, YM; Marx, DB; Nickel, JC

    2015-01-01

    Objectives Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces. Setting and Sample Population School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in 4 groups based on presence/absence (+/-) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD). Material & Methods Validated numerical models employed an organizational objective and subjects’ anatomy to calculate masticatory muscle forces during static biting. ANOVA and Holm step-down procedure post-hoc tests assessed group differences. Theoretical geometries, representing the range of subjects’ muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect-size (Cohen’s d) and ANOVA/post-hoc tests assessed group differences in key muscle orientations. Results +P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (P<0.01) for bite-forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly-directed for temporalis muscles (all Cohen’s d ≥0.8). Conclusion Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations. PMID:25865546

  5. Effects of mouthguards on vertical dimension, muscle activation, and athlete preference: a prospective cross-sectional study.

    PubMed

    Gage, C Colby; Huxel Bliven, Kellie C; Bay, R Curtis; Sturgill, Jeremiah S; Park, Jae Hyun

    2015-01-01

    Mandibular repositioning and subsequent neuromuscular signaling are proposed mechanisms of action for commercial mouthguards marketed for performance enhancement. A prospective cross-sectional study of 24 healthy adult weightlifters with normal occlusal relationships was designed to determine whether 2 self-fit performance mouthguards; a custom-fabricated, bilaterally balanced, dual-laminated mouthguard; and no mouthguard (control) differed in their effects on vertical dimension, muscle activation, and user preference during a 75% maximum power clean lift. Each subject was tested for each of the mouthguard categories: Power Balance POWERUP, Under Armour ArmourBite, custom, and no mouthguard. Interocclusal distance was measured at baseline and with each mouthguard. Mean and peak activity of the anterior temporalis, masseter, sternocleidomastoid, and cervical paraspinal muscles was measured during sitting and during a 75% maximum power clean lift. A mouthguard preference questionnaire was completed. Analyses were conducted to determine whether interocclusal distance differed among mouthguard type and to examine the effect of mouthguard type on mean and peak muscle activation during the clean lift. Interocclusal distance was affected by mouthguard type (P = 0.01). Mean and peak activity of the anterior temporalis and masseter muscles and mean activity of the sternocleidomastoid muscle differed among mouthguards (P < 0.05). Mouthguard type did not influence muscle activation of the cervical paraspinal muscle group. Overall, the Power Balance mouthguard produced more muscle activity. Participants preferred custom mouthguards nearly 2:1 over self-fit performance mouthguards (P = 0.05). Participants perceived that they were stronger and were less encumbered when using a custom mouthguard during submaximum power clean lifts. PMID:26545275

  6. Surface electromyography pattern of human swallowing

    PubMed Central

    Monaco, Annalisa; Cattaneo, Ruggero; Spadaro, Alessandro; Giannoni, Mario

    2008-01-01

    Background The physiology of swallowing is characterized by a complex and coordinated activation of many stomatognathic, pharyngeal, and laryngeal muscles. Kinetics and electromyographic studies have widely investigated the pharyngeal and laryngeal pattern of deglutition in order to point out the differences between normal and dysphagic people. In the dental field, muscular activation during swallowing is believed to be the cause of malocclusion. Despite the clinical importance given to spontaneous swallowing, few physiologic works have studied stomatognathic muscular activation and mandibular movement during spontaneous saliva swallowing. The aim of our study was to investigate the activity patterns of the mandibular elevator muscles (masseter and anterior temporalis muscles), the submental muscles, and the neck muscles (sternocleidomastoid muscles) in healthy people during spontaneous swallowing of saliva and to relate the muscular activities to mandibular movement. Methods The spontaneous swallowing of saliva of 111 healthy individuals was analyzed using surface electromyography (SEMG) and a computerized kinesiography of mandibular movement. Results Fifty-seven of 111 patients swallowed without occlusal contact (SNOC) and 54 individuals had occlusal contact (SOC). The sternocleidomastoid muscles showed a slight, but constant activation during swallowing. The SEMG of the submental and sternocleidomastoid muscles showed no differences between the two groups. The SEMG of the anterior temporalis and masseter muscles showed significant differences (p < 0.0001). The duration of swallowing was significantly higher in the SNOC subjects. Gender and age were not related to electromyographic activation. Healthy SOC and SNOC behaved in different ways. Conclusion The data suggest that there is not a single "normal" or "typical" pattern for spontaneous saliva swallowing. The polygraph seemed a valuable, simple, non-invasive and reliable tool to study the physiology of

  7. Morphological adaptation to diet in platyrrhine primates.

    PubMed

    Anapol, F; Lee, S

    1994-06-01

    Morphological features of the jaws and teeth are examined in eight species of platyrrhine monkeys that coexist in the Suriname rainforest. Z-scores calculated from geometric predictions for several features of the feeding apparatus thought to have some functional significance (e.g., tooth dimensions, jaw robusticity, leverage of primary jaw elevators) are compared to a profile of the naturalistic dietary behavior of these species (i.e., proportions of fruit mesocarp, seeds, leaves, and fauna eaten). Several features are found exclusively in those platyrrhines whose dietary preferences are the most limited. Such specializations appear to be associated with a particular protein source exploited by a species to supplement a largely frugivorous diet. Ateles paniscus, which feeds primarily on the mesocarp of ripe fruit, has an adaptive morphology that emphasizes broad incisors. Chiropotes satanas (and to a slightly lesser extent, Pithecia pithecia) is a frugivore/seed predator with large upper and lower canines and a robust mandible. The frugivore/folivore Alouatta seniculus has a relatively large total molar area and effective mandibular condyle height. In all four of these strictly vegetarian species, the leverage of the masseter muscle is greater than that of temporalis. Of the omnivorous species, Cebus apella and C. nigrivittatus exploit both fauna and seeds for protein and exhibit an array of many of the above features, such as large teeth and thick mandibles. Saimiri sciureus, not particularly known for seed predation, departs from Cebus in having less robust canines and a more gracile mandible. All three cebid omnivores have a temporalis with greater leverage than the masseter, indicating a requirement for resisting anteriorly directed forces, for example, using the jaws for vigorous foraging. The lack of any enlarged features, other than incisors, in the omnivorous Saguinus midas may be attributable to the functional constraints of small body size. Because the

  8. The relationship between the temporomandibular joint capsule, articular disc and jaw muscles.

    PubMed Central

    Schmolke, C

    1994-01-01

    The anatomy of the temporomandibular joint capsule and its possible relationships to other structures near the joint are not fully understood. A 3-dimensional analysis based on sagittal, frontal and horizontal serial sections through the human temporomandibular joint region was therefore undertaken. Capsular elements which directly connect the temporal bone with the mandible were seen only on the lateral side of the joint. In the posterior, anterior and medial regions of the joint the upper and lower laminae of the articular disc are attached separately either to the temporal bone or to the mandibular condyle. The shaping of the articular cavities and the texture of the joint capsule permit movements of the articular disc predominantly in the anteromedial direction. On the entire medial side of the joint the articular disc and its capsular attachments are in close contact with the fascia of the lateral pterygoid muscle whereby a small portion of the upper head of this muscle inserts directly into the anteromedial part of the articular disc. Thus both the upper and the lower heads of the lateral pterygoid muscle are likely to influence the position of the articular disc directly during temporomandibular joint movements. Laterally, the articular disc is attached to the fascia of the masseter muscle, and part of the lateral ligament inserts into the temporalis fascia. Since these attachments are relatively weak, neither the temporalis nor the masseter muscles are considered to act directly on the articular disc; instead, via afferents from muscle spindles, they may take part in signalling the position of the temporomandibular joint components, including that of the articular disc. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8014124

  9. Deep pain sensitivity is correlated with oral-health-related quality of life but not with prosthetic factors in complete denture wearers.

    PubMed

    Costa, Yuri Martins; Porporatti, André Luís; Hilgenberg-Sydney, Priscila Brenner; Bonjardim, Leonardo Rigoldi; Conti, Paulo César Rodrigues

    2015-01-01

    Low pressure Pain Threshold (PPT) is considered a risk factor for Temporomandibular Disorders (TMD) and is influenced by psychological variables. Objectives To correlate deep pain sensitivity of masticatory muscles with prosthetic factors and Oral-Health-Related Quality of Life (OHRQoL) in completely edentulous subjects. Material and Methods A total of 29 complete denture wearers were recruited. The variables were: a) Pressure Pain Threshold (PPT) of the masseter and temporalis; b) retention, stability, and tooth wear of dentures; c) Vertical Dimension of Occlusion (VDO); d) Oral Health Impact Profile (OHIP) adapted to orofacial pain. The Kolmogorov-Smirnov test, the Pearson Product-Moment correlation coefficient, the Spearman Rank correlation coefficient, the Point-Biserial correlation coefficient, and the Bonferroni correction (α=1%) were applied to the data. Results The mean age (standard deviation) of the participants was of 70.1 years (9.5) and 82% of them were females. There were no significant correlations with prosthetic factors, but significant negative correlations were found between the OHIP and the PPT of the anterior temporalis (r=-0.50, 95% CI-0.73 to 0.17, p=0.005). Discussion The deep pain sensitivity of masticatory muscles in complete dentures wearers is associated with OHRQoL, but not with prosthetic factors. PMID:26814457

  10. Deep pain sensitivity is correlated with oral-health-related quality of life but not with prosthetic factors in complete denture wearers

    PubMed Central

    COSTA, Yuri Martins; PORPORATTI, André Luís; HILGENBERG-SYDNEY, Priscila Brenner; BONJARDIM, Leonardo Rigoldi; CONTI, Paulo César Rodrigues

    2015-01-01

    ABSTRACT Low pressure Pain Threshold (PPT) is considered a risk factor for Temporomandibular Disorders (TMD) and is influenced by psychological variables. Objectives To correlate deep pain sensitivity of masticatory muscles with prosthetic factors and Oral-Health-Related Quality of Life (OHRQoL) in completely edentulous subjects. Material and Methods A total of 29 complete denture wearers were recruited. The variables were: a) Pressure Pain Threshold (PPT) of the masseter and temporalis; b) retention, stability, and tooth wear of dentures; c) Vertical Dimension of Occlusion (VDO); d) Oral Health Impact Profile (OHIP) adapted to orofacial pain. The Kolmogorov-Smirnov test, the Pearson Product-Moment correlation coefficient, the Spearman Rank correlation coefficient, the Point-Biserial correlation coefficient, and the Bonferroni correction (α=1%) were applied to the data. Results The mean age (standard deviation) of the participants was of 70.1 years (9.5) and 82% of them were females. There were no significant correlations with prosthetic factors, but significant negative correlations were found between the OHIP and the PPT of the anterior temporalis (r=-0.50, 95% CI-0.73 to 0.17, p=0.005). Discussion The deep pain sensitivity of masticatory muscles in complete dentures wearers is associated with OHRQoL, but not with prosthetic factors. PMID:26814457

  11. [A clinical study on the relationship between chewing movements and masticatory muscle activities].

    PubMed

    Higashi, K

    1989-06-01

    Chewing movement is one of the most important functional and physiological jaw movements, and it is coordinated by the three elements of the functional occlusion system (teeth, TMJs and masticatory muscles). However, the relationship between chewing movement and these elements has not been clarified. The purpose of this study was to investigate the relationship between chewing movement and the activity of the masticatory muscles which directly control jaw movements. 25 subjects with normal stomatognathic function, 5 patients with MPD syndrome (muscle dysfunction group) and 5 patients with unilateral TMJ internal derangement (TMJ dysfunction group) were selected. 6 gums with different hardness were used as the test bolus. Sirognathograph Electromyograph Analysing System was used to simultaneously record chewing movements and electromyograms of the right and left masseter, anterior temporal, posterior temporal and anterior belly of digastric muscles. Using the analysing software which was developed for this study, chewing movements and muscle activities were analysed. The results were as follow; A. In normal subjects 1. Gum hardness influenced durations of the closing and occluding phases, maximum opening and closing speed, opening degree and deviation of opening and closing path. 2. Gum hardness influenced muscle activities except of the time factors of digastric bursts. 3. Durations of the closing and occluding phases were found to be related with the elevator muscle activities. Maximum closing speed was related with the masseter and anterior temporal muscle activities. Deviation of closing path was related with the anterior and posterior temporal muscle activities. B. In abnormal subjects 1. The changes mainly observed in the muscle activities were found to be significantly different between the muscle dysfunction group and normal group. Similarly, the changes mainly observed in the chewing movements were different between the TMJ dysfunction group and normal

  12. Effects on non-human primate mastication of reversible inactivation by cooling of the face primary somatosensory cortex.

    PubMed

    Lin, L D; Murray, G M; Sessle, B J

    1998-02-01

    Rhythmical jaw movements can be evoked by intracortical microstimulation within four physiologically defined regions, one of which is the primary face somatosensory cortex (face SI). It has been proposed that these regions may be involved in the selection and/or control of masticatory patterns generated at the brainstem level. The aim here was to determine if mastication is affected by reversible, cooling-induced inactivation of the face SI. Two cranial chambers were chronically implanted in two monkeys (Macaca fascicularis) to allow access bilaterally to the face SI. A thermode was placed on the dura or pia overlying each SI that had been shown with micro-electrode recordings to receive intraoral inputs. A hot or cold alcohol-water solution was pumped through the thermodes while the monkey chewed a small piece of apple or a sultana during precool (thermode temperature, 37 degree C), cool (2-4 degrees C), and postcool (37 degrees C) conditions. Electromyographic (EMG) activity was recorded intramuscularly from the masseter, genioglossus, and anterior digastric. Cooling of SI impaired rhythmical jaw and tongue movements and EMG activity associated with mastication in one monkey (H5), and modified the pattern of EMG activity in the other (H6). The total masticatory time (i.e., time taken for chewing and manipulation of the bolus before swallowing) was increased. This was due principally to an increase in the oral transport time (i.e., time taken for manipulation of bolus after chewing and before swallowing: monkey H6, control, 2.7 sec; cool, 5.2 sec, p < 0.05); the bolus was manipulated by the tongue during this period before swallowing. Within the chewing time (i.e., time during which chewing occurred), cooling resulted in a significant increase in anterior digastric muscle duration, a significant delay in the onset of masseter EMG activity, and a significant increase in the variance of genioglossus EMG duration. The data support the view that the face SI plays a

  13. Boomerang-Shaped Chondro-Perichondral Graft Versus Temporalis Muscle Fascia Graft: Which One is to be Trusted?

    PubMed

    Dundar, Riza; Kulduk, Erkan; Soy, Fatih Kemal; Aslan, Mehmet; Yükkaldiran, Ahmet; Çiftçi, Mehmet Ali

    2016-09-01

    The aim of this study was to compare anatomical and audiological results of boomerang-shaped chondroperichondrial graft (BSCPG) with temporal muscle fascia in type 1 tympanoplasties. Sixty-eight patients in BSCPG group and 54 patients in fascia group were evaluated. Otomicroscopic examination was done periodically till 24 months as for graft perforation, lateralization and retraction and mean air conduction threshold and airbone gap values were measured. At long term controls, in BSCPG group, rates of neomembrane, perforation, retraction and lateralization were 91.17 % (n = 62), 8.82 % (n = 6), 4.41 % (n = 3) and 0 % (n = 0), respectively. In fascia group, the corresponding rates were 79.62 % (n = 43), 20.37 % (n = 11), 12.96 % (n = 7) and 3.7 % (n = 2), respectively. In both groups, mean postoperative PTA and ABG values were significantly better while postoperative same values were significantly different between groups (p = 0.044 and 0.032, respectively). Compared to fascia, BSCPG is an ideal grafting technique in the repair of tympanic membrane perforations. PMID:27508137

  14. Adaptation of the muscles of mastication to the flat skull feature in the polar bear (Ursus maritimus).

    PubMed

    Sasaki, M; Endo, H; Yamagiwa, D; Takagi, H; Arishima, K; Makita, T; Hayashi, Y

    2000-01-01

    The muscles of mastication of the polar bear (Ursus maritimus) and those of the brown bear (U. arctos) were examined by anatomical approach. In addition, the examination of the skull was carried out in the polar bear, brown bear and giant panda (Ailuropoda melanoleuca). In the polar bear, the rostro-ventral part of the superficial layer of the M. masseter possessed the abundant fleshy portion folded in the rostral and lateral directions like an accordion. Moreover, the rostro-medial area of the superficial layer became hollow in the nuchal direction when the mouth was closed. The M. temporalis of the polar bear covered up the anterior border of the coronoid process of the mandible and occupied the almost entire area of the cranial surface. The M. pterygoideus medialis of the polar bear was inserted on the ventral border of the mandible and on the ventral part of the temporal bone more widely than that of the brown bear. As results of our measurements of the mandible, an effect of the leverage in the polar bear was the smallest in three species. In the polar bear, the skull was flat, and the space between zygomatic arch and ventral border of the mandible, occupied by the M. masseter was the narrowest. It is suggested that the muscles of mastication of the polar bear is adapted to the flat skull feature for supplementing the functions. PMID:10676883

  15. Evaluation of low-level laser therapy in the treatment of masticatory muscles spasticity in children with cerebral palsy

    NASA Astrophysics Data System (ADS)

    Santos, Maria Teresa Botti Rodrigues; Diniz, Michele Baffi; Gouw-Soares, Sheila Cynthia; Lopes-Martins, Rodrigo Alvaro Brandão; Frigo, Lucio; Baeder, Fernando Martins

    2016-02-01

    Spasticity is a motor disorder frequently present in individuals with cerebral palsy (CP). This study aimed to evaluate the effect of low-level laser therapy (LLLT) on the spasticity of the masseter and anterior temporal muscle fibers in children with CP over three weeks of intermittent laser exposures. The bite force (BF) of the masticatory muscles and the amplitude of mouth opening were evaluated before and after laser irradiation in 30 children with CP. Both sides of the masseter and temporalis muscles were irradiated with low-intensity diode laser pulses of 808-nm wavelength six times over three consecutive weeks. During the subsequent three weeks of postlaser exposures, although no laser treatment was applied, the evaluation parameters were measured and recorded. A significant improvement in the amplitude of mouth opening and a decrease in the BF were observed in the weeks following LLLT (P<0.05). However, by the sixth week post-LLLT, the BF and the amplitude of mouth opening reverted to values equivalent to those obtained before the first application of LLLT. Our investigation revealed low-level energy exposures from a 808-nm diode laser to be an effective short-term therapeutic tool. This method increased the amplitude of mouth opening and decreased the muscle tonus of children with spastic CP over a time course of three weeks of intermittent laser applications.

  16. Evaluation of low-level laser therapy in the treatment of masticatory muscles spasticity in children with cerebral palsy.

    PubMed

    Santos, Maria Teresa Botti Rodrigues; Diniz, Michele Baffi; Gouw-Soares, Sheila Cynthia; Lopes-Martins, Rodrigo Alvaro Brandão; Frigo, Lucio; Baeder, Fernando Martins

    2016-02-01

    Spasticity is a motor disorder frequently present in individuals with cerebral palsy (CP). This study aimed to evaluate the effect of low-level laser therapy (LLLT) on the spasticity of the masseter and anterior temporal muscle fibers in children with CP over three weeks of intermittent laser exposures. The bite force (BF) of the masticatory muscles and the amplitude of mouth opening were evaluated before and after laser irradiation in 30 children with CP. Both sides of the masseter and temporalis muscles were irradiated with low-intensity diode laser pulses of 808-nm wavelength six times over three consecutive weeks. During the subsequent three weeks of postlaser exposures, although no laser treatment was applied, the evaluation parameters were measured and recorded. A significant improvement in the amplitude of mouth opening and a decrease in the BF were observed in the weeks following LLLT (P<0.05 ). However, by the sixth week post-LLLT, the BF and the amplitude of mouth opening reverted to values equivalent to those obtained before the first application of LLLT. Our investigation revealed low-level energy exposures from a 808-nm diode laser to be an effective short-term therapeutic tool. This method increased the amplitude of mouth opening and decreased the muscle tonus of children with spastic CP over a time course of three weeks of intermittent laser applications. PMID:26882450

  17. A pilot study of ambulatory masticatory muscle activities in TMJD diagnostic groups

    PubMed Central

    Iwasaki, LR; Gonzalez, YM; Liu, H; Marx, DB; Gallo, LM; Nickel, JC

    2015-01-01

    Objective To determine differences in masticatory muscle usage between TMJD diagnostic groups. Setting and Sample Population Seventy-one informed and consented subjects (27 men; 44 women) participated at the University at Buffalo. Material and Methods Research Diagnostic Criteria and imaging data were used to categorize subjects according to presence/absence (+/−) of TMJ disc placement (DD) and chronic pain (P) (+DD+P, n=18; +DD-P, n =14; −DD-P, n=39). EMG/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20 N bite-force (T20N, μV). Over 3 days and nights subjects collected EMG recordings. Duty factors (DFs, % of recording time) were determined based on threshold intervals (5–9, 10–24, 25–49, 50–79, ≥80%T20N). ANOVA and Tukey-Kramer post-hoc tests identified (i) diagnostic group differences in T20N, and (ii) effects of diagnostic group, gender, time, and interval, and on muscle DFs. Results Mean (±standard error) temporalis T20N in +DD+P subjects was significantly higher (71.4±8.8 μV) than masseter T20N in these subjects (19.6±8.8 μV; P=0.001) and in −DD-P subjects (25.3±6.0 μV, P=0.0007). Masseter DFs at 5–9%T20N were significantly higher in +DD-P women (3.48%) than +DD-P men (0.85%) and women and men in both other diagnostic groups (all P<0.03); and in +DD+P women (2.00%) compared to −DD-P men (0.83%; P=0.029). Night-time DFs at 5–9%T20N in +DD-P women (1.97%) were significantly higher than in −DD-P men (0.47%) and women (0.24%; all P<0.01). Conclusions Between-group differences were found in masticatory muscle activities in both laboratory and natural environmental settings. PMID:25865543

  18. Influence of playing wind instruments on activity of masticatory muscles.

    PubMed

    Gotouda, A; Yamaguchi, T; Okada, K; Matsuki, T; Gotouda, S; Inoue, N

    2007-09-01

    The aim of this study was to elucidate the influence of change in sound tone of playing wind instruments on activity of jaw-closing muscles and the effect of sustained playing for a long time on fatigue of jaw-closing muscles. Electromyograms (EMG) of 19 brass instrument players and 14 woodwind instrument players were measured while playing instruments in tuning tone and high tone and under other conditions. Nine brass instrument players and nine woodwind instrument players played instruments for 90 min. Before and after the exercise, power spectral analyses of EMG from masseter muscles at 50% of maximum voluntary clenching level were performed and mean power frequency (MPF) were calculated. Root mean square (RMS) of EMG in masseter and temporal muscles while playing were slightly larger than those at rest but extremely small in comparison with those during maximum clenching. Root mean square in orbicularis oris and digastric muscles were relatively large when playing instruments. In the brass instrument group, RMS in high tone was significantly higher than that in tuning tone in all muscles examined. In the woodwind instrument group, RMS in high tone was not significantly higher than that in tuning tone in those muscles. Mean power frequency was not decreased after sustained playing in both instrument groups. These findings indicate that contractive load to jaw-closing muscles when playing a wind instrument in both medium and high tone is very small and playing an instrument for a long time does not obviously induce fatigue of jaw-closing muscles. PMID:17716263

  19. Electromyography of Swallowing with Fine Wire Intramuscular Electrodes in Healthy Human: Amplitude Difference of Selected Hyoid Muscles.

    PubMed

    Inokuchi, Haruhi; González-Fernández, Marlís; Matsuo, Koichiro; Brodsky, Martin B; Yoda, Mitsumasa; Taniguchi, Hiroshige; Okazaki, Hideto; Hiraoka, Takashi; Palmer, Jeffrey B

    2016-02-01

    Few studies have examined the intensity of muscle activity during swallowing in healthy humans. We examined selected hyoid muscles using fine wire intramuscular electromyography (EMG) during swallowing of four food consistencies. Thirteen healthy adults were studied using videofluorography and EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), and masseter (MA; surface electrodes) while ingesting thin liquid (three trials) and solid food of three consistencies (banana, tofu, and cookie, three trials each). After rectification, integration, and normalization, peak EMG amplitudes for each muscle in each trial were measured. Hyoid displacements were measured in two dimensions. Data were analyzed using repeated measures ANOVA with Bonferroni correction. GH had the highest adjusted amplitude for both solids and liquid. For MA and ABD, amplitude was highest with triturated cookie. For ABD, amplitude was lowest with liquid. There were no significant food consistency effects for GH or SH. Hyoid displacements were greatest for cookie and the lowest for liquid. EMG amplitude varied with initial food consistency. The high peak EMG amplitude of GH is consistent with its essential role in opening the upper esophageal sphincter. High MA amplitude with hard solid foods is likely due to the higher tongue-palate pressure with triturated solids. The higher ABD amplitude with solid food is associated with greater hyoid displacement. These findings support the existence of a central pattern generator that modifies the level of muscle activity during pharyngeal swallowing in response to input from mechanoreceptors in the oral cavity. PMID:26487062

  20. Temporomandibular joint health status in war veterans with post-traumatic stress disorder

    PubMed Central

    Mottaghi, Ahmad; Zamani, Elham

    2014-01-01

    Background and Aim: The objective of this study was to determine the prevalence of signs and symptoms of temporomandibular joint dysfunction (TMJD) in the Iran/Iraq war veterans suffering from post-traumatic stress disorder. Materials and Methods: A total of 120 subjects in the age range of 27 to 55 years were included; it included case group (30 war veterans with PTSD) and three control groups (30 patients with PTSD who had not participated in the War, 30 healthy war veterans, and 30 healthy subjects who had not participated in the War). All subjects underwent a clinical TMJ examination that involved the clinical assessment of the TMJ signs and symptoms. Results: The groups of veterans had high prevalence of TMJD signs and symptoms vs. other groups; history of Trauma to joint was significantly higher in subjects who had participated in the war compare with subjects who had not participated in the war (P = 0.0006). Furthermore, pain in palpation of masseter, temporal, pterygoideus, digastric, and sternocleidomastoid muscles in the groups of veterans was significantly greater than other groups (P < 0.0001). Clicking noise during mouth chewing was significantly different between groups (P = 0.01). And, there was significant difference in the frequencies of maximum opening of the mouth between groups (P = 0.001). Conclusion: The results of this study showed that subjects’ war veterans with PTSD have significantly poorer TMJ functional status than the control subjects. PMID:25077153

  1. Differential involvement of two cortical masticatory areas in submandibular salivary secretion in rats.

    PubMed

    Maeda, Naoto; Kobashi, Motoi; Mitoh, Yoshihiro; Fujita, Masako; Minagi, Shogo; Matsuo, Ryuji

    2014-01-16

    To evaluate the role of the masticatory area in the cerebral cortex in the masticatory-salivary reflex, we investigated submandibular salivary secretion, jaw-movement trajectory and electromyographic activity of the jaw-opener (digastric) and jaw-closer (masseter) muscles evoked by repetitive electrical stimulation of the cortical masticatory area in anesthetized rats. Rats have two cortical masticatory areas: the anterior area (A-area) in the orofacial motor cortex, and the posterior area (P-area) in the insular cortex. Our defined P-area extended more caudally than the previous reported one. P-area stimulation induced vigorous salivary secretion (about 20 µl/min) and rhythmical jaw movements (3-4 Hz) resembling masticatory movements. Salivary flow persisted even after minimizing jaw movements by curarization. A-area stimulation induced small and fast rhythmical jaw movements (6-8 Hz) resembling licking of solutions, but not salivary secretion. These findings suggest that P-area controls salivary secretion as well as mastication, and may be involved in the masticatory-salivary reflex. PMID:24309141

  2. Effects of Botulinum Toxin on Jaw Motor Events during Sleep in Sleep Bruxism Patients: A Polysomnographic Evaluation

    PubMed Central

    Shim, Young Joo; Lee, Moon Kyu; Kato, Takafumi; Park, Hyung Uk; Heo, Kyoung; Kim, Seong Taek

    2014-01-01

    Study Objectives: To investigate the effects of botulinum toxin type A (BoNT-A) injection on jaw motor episodes during sleep in patients with or without orofacial pain who did not respond to oral splint treatment. Methods: Twenty subjects with a clinical diagnosis of SB completed this study. Ten subjects received bilateral BoNT-A injections (25 U per muscle) into the masseter muscles only (group A), and the other 10 received the injections into both the masseter and temporalis muscles (group B). Video-polysomnographic (vPSG) recordings were made before and at 4 weeks after injection. Rhythmic masticatory muscle activity (RMMA) and orofacial activity (OFA) were scored and analyzed for several parameters (e.g., frequency of episodes, bursts per episode, episode duration). The peak amplitude of electromyographic (EMG) activity in the two muscles was also measured. Results: BoNT-A injection did not reduce the frequency, number of bursts, or duration for RMMA episodes in the two groups. The injection decreased the peak amplitude of EMG burst of RMMA episodes in the injected muscles (p < 0.001, repeated measure ANOVA) in both groups. At 4 weeks after injection, 9 subjects self-reported reduction of tooth grinding and 18 subjects self-reported reduction of morning jaw stiffness. Conclusions: A single BoNT-A injection is an effective strategy for controlling SB for at least a month. It reduces the intensity rather than the generation of the contraction in jaw-closing muscles. Future investigations on the efficacy and safety in larger samples over a longer follow-up period are needed before establishing management strategies for SB with BoNT-A. Citation: Shim YJ; Lee MK; Kato T; Park HU; Heo K; Kim ST. Effects of botulinum toxin on jaw motor events during sleep in sleep bruxism patients: a polysomnographic evaluation. J Clin Sleep Med 2014;10(3):291-298. PMID:24634627

  3. Effects of Neuromuscular Electrical Stimulation on the Masticatory Muscles and Physiologic Sleep Variables in Adults with Cerebral Palsy: A Novel Therapeutic Approach

    PubMed Central

    Giannasi, Lilian Chrystiane; Matsui, Miriam Yumi; Freitas, Sandra Regina Batista; Caldas, Bruna F.; Grossmann, Eduardo; Amorim, José Benedito O.; dos Santos, Israel dos Reis; Oliveira, Luis Vicente Franco; Oliveira, Claudia Santos; Gomes, Monica Fernandes

    2015-01-01

    Cerebral palsy (CP) is a term employed to define a group of non-progressive neuromotor disorders caused by damage to the immature or developing brain, with consequent limitations regarding movement and posture. CP may impair orapharygeal muscle tone, leading to a compromised chewing function and to sleep disorders (such as obstructive sleep apnea). Thirteen adults with CP underwent bilateral masseter and temporalis neuromuscular electrical stimulation (NMES) therapy. The effects on the masticatory muscles and sleep variables were evaluated using electromyography (EMG) and polysomnography (PSG), respectively, prior and after 2 months of NMES. EMG consisted of 3 tests in different positions: rest, mouth opening and maximum clenching effort (MCE). EMG values in the rest position were 100% higher than values recorded prior to therapy for all muscles analyzed (p < 0.05); mean mouth opening increased from 38.0 ± 8.0 to 44.0 ± 10.0 cm (p = 0.03). A significant difference in MCE was found only for the right masseter. PSG revealed an improved in the AHI from 7.2±7.0/h to 2.3±1.5/h (p < 0.05); total sleep time improved from 185 min to 250 min (p = 0.04) and minimun SaO2 improved from 83.6 ± 3.0 to 86.4 ± 4.0 (p = 0.04). NMES performed over a two-month period led to improvements in the electrical activity of the masticatory muscles at rest, mouth opening, isometric contraction and sleep variables, including the elimination of obstructive sleep apnea events in patients with CP. Trial Registration ReBEC RBR994XFS http://www.ensaiosclinicos.gov.br PMID:26247208

  4. The effect of culture on pain sensitivity.

    PubMed

    Al-Harthy, M; Ohrbach, R; Michelotti, A; List, T

    2016-02-01

    Cross-cultural differences in pain sensitivity have been identified in pain-free subjects as well as in chronic pain patients. The aim was to assess the impact of culture on psychophysical measures using mechanical and electrical stimuli in patients with temporomandibular disorder (TMD) pain and pain-free matched controls in three cultures. This case-control study compared 122 female cases of chronic TMD pain (39 Saudis, 41 Swedes and 42 Italians) with equal numbers of age- and gender-matched TMD-free controls. Pressure pain threshold (PPT) and tolerance (PPTo) were measured over one hand and two masticatory muscles. Electrical perception threshold and electrical pain threshold (EPT) and tolerance (EPTo) were recorded between the thumb and index fingers. Italian females reported significantly lower PPT in the masseter muscle than other cultures (P < 0.001) and in the temporalis muscle than Saudis (P = 0.003). Swedes reported significantly higher PPT in the thenar muscle than other cultures (P = 0.017). Italians reported significantly lower PPTo in all muscles than Swedes (P ≤ 0.006) and in the masseter muscle than Saudis (P < 0.001). Italians reported significantly lower EPTo than other cultures (P = 0.01). Temporomandibular disorder cases, compared to TMD-free controls, reported lower PPT and PPTo in all the three muscles (P < 0.001). This study found cultural differences between groups in the PPT, PPTo and EPTo. Overall, Italian females reported the highest sensitivity to both mechanical and electrical stimulation, while Swedes reported the lowest sensitivity. Mechanical pain thresholds differed more across cultures than did electrical pain thresholds. Cultural factors may influence response to type of pain test. PMID:26371794

  5. New method of neck surface electromyography for the evaluation of tongue-lifting activity.

    PubMed

    Manda, Y; Maeda, N; Pan, Q; Sugimoto, K; Hashimoto, Y; Tanaka, Y; Kodama, N; Minagi, S

    2016-06-01

    Elevation of the posterior part of the tongue is important for normal deglutition and speech. The purpose of this study was to develop a new surface electromyography (EMG) method to non-invasively and objectively evaluate activity in the muscles that control lifting movement in the posterior tongue. Neck surface EMG (N-EMG) was recorded using differential surface electrodes placed on the neck, 1 cm posterior to the posterior border of the mylohyoid muscle on a line orthogonal to the lower border of the mandible. Experiment 1: Three healthy volunteers (three men, mean age 37·7 years) participated in an evaluation of detection method of the posterior tongue lifting up movement. EMG recordings from the masseter, temporalis and submental muscles and N-EMG revealed that i) N-EMG was not affected by masseter muscle EMG and ii) N-EMG activity was not observed during simple jaw opening and tongue protrusion, revealing the functional difference between submental surface EMG and N-EMG. Experiment 2: Seven healthy volunteers (six men and one woman, mean age 27·9 years) participated in a quantitative evaluation of muscle activity. Tongue-lifting tasks were perfor-med, exerting a prescribed force of 20, 50, 100 and 150 gf with visual feedback. For all subjects, a significant linear relationship was observed bet-ween the tongue-lifting force and N-EMG activity (P < 0·01). These findings indicate that N-EMG can be used to quantify the force of posterior tongue lifting and could be useful to evaluate the effect of tongue rehabilitation in future studies. PMID:26860767

  6. The clenching-grinding spectrum and fear circuitry disorders: clinical insights from the neuroscience/paleoanthropology interface.

    PubMed

    Bracha, H Stefan; Ralston, Tyler C; Williams, Andrew E; Yamashita, Jennifer M; Bracha, Adam S

    2005-04-01

    This review discusses the clenching-grinding spectrum from the neuropsychiatric/neuroevolutionary perspective. In neuropsychiatry, signs of jaw clenching may be a useful objective marker for detecting or substantiating a self-report of current subjective emotional distress. Similarly, accelerated tooth wear may be an objective clinical sign for detecting, or substantiating, long-lasting anxiety. Clenching-grinding behaviors affect at least 8 percent of the population. We argue that during the early paleolithic environment of evolutionary adaptedness, jaw clenching was an adaptive trait because it rapidly strengthened the masseter and temporalis muscles, enabling a stronger, deeper and therefore more lethal bite in expectation of conflict (warfare) with conspecifics. Similarly, sharper incisors produced by teeth grinding may have served as weaponry during early human combat. We posit that alleles predisposing to fear-induced clenching-grinding were evolutionarily conserved in the human clade (lineage) since they remained adaptive for anatomically and mitochondrially modern humans (Homo sapiens) well into the mid-paleolithic. Clenching-grinding, sleep bruxism, myofacial pain, craniomaxillofacial musculoskeletal pain, temporomandibular disorders, oro-facial pain, and the fibromyalgia/chronic fatigue spectrum disorders are linked. A 2003 Cochrane meta-analysis concluded that dental procedures for the above spectrum disorders are not evidence based. There is a need for early detection of clenching-grinding in anxiety disorder clinics and for research into science-based interventions. Finally, research needs to examine the possible utility of incorporating physical signs into Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition posttraumatic stress disorder diagnostic criteria. One of the diagnostic criterion that may need to undergo a revision in Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition is Criterion D (persistent fear

  7. Evaluation of jaw and neck muscle activities while chewing using EMG-EMG transfer function and EMG-EMG coherence function analyses in healthy subjects.

    PubMed

    Ishii, Tomohiro; Narita, Noriyuki; Endo, Hiroshi

    2016-06-01

    This study aims to quantitatively clarify the physiological features in rhythmically coordinated jaw and neck muscle EMG activities while chewing gum using EMG-EMG transfer function and EMG-EMG coherence function analyses in 20 healthy subjects. The chewing side masseter muscle EMG signal was used as the reference signal, while the other jaw (non-chewing side masseter muscle, bilateral anterior temporal muscles, and bilateral anterior digastric muscles) and neck muscle (bilateral sternocleidomastoid muscles) EMG signals were used as the examined signals in EMG-EMG transfer function and EMG-EMG coherence function analyses. Chewing-related jaw and neck muscle activities were aggregated in the first peak of the power spectrum in rhythmic chewing. The gain in the peak frequency represented the power relationships between jaw and neck muscle activities during rhythmic chewing. The phase in the peak frequency represented the temporal relationships between the jaw and neck muscle activities, while the non-chewing side neck muscle presented a broad range of distributions across jaw closing and opening phases. Coherence in the peak frequency represented the synergistic features in bilateral jaw closing muscles and chewing side neck muscle activities. The coherence and phase in non-chewing side neck muscle activities exhibited a significant negative correlation. From above, the bilateral coordination between the jaw and neck muscle activities is estimated while chewing when the non-chewing side neck muscle is synchronously activated with the jaw closing muscles, while the unilateral coordination is estimated when the non-chewing side neck muscle is irregularly activated in the jaw opening phase. Thus, the occurrence of bilateral or unilateral coordinated features in the jaw and neck muscle activities may correspond to the phase characteristics in the non-chewing side neck muscle activities during rhythmical chewing. Considering these novel findings in healthy subjects, EMG

  8. Dental Implants – Perceiving Patients’ Satisfaction in Relation to Clinical and Electromyography Study on Implant Patients

    PubMed Central

    Saha, Soumendra

    2015-01-01

    The aim of this study is to evaluate the satisfaction of patients with posterior implants in relation to the clinical success criteria and surface electromyography (sEMG) findings of the masseter and temporalis muscles. Total 42 subjects were investigated. Twenty one subjects with posterior dental implants were interviewed using a questionnaire and the clinical success criteria were determined based on The International Congress of Oral Implantologists. The myofunction of the masticatory muscles were assessed using sEMG (21 subjects) and compared to the control group of subjects without implants (21 subjects). Out of 21 subjects, all were satisfied with the aesthetics of their implant. Twenty of them (95.2%) were satisfied with its function and stability. As for clinical criteria, 100% (50) of the implants were successful with no pain, mobility or exudates. sEMG findings showed that patients have significantly lower (p<0.01) basal or resting median power frequency but with muscle burst. During chewing, control subjects showed faster chewing action. There was no difference in reaction and recovery time of clenching for both groups. In conclusion, the satisfaction of implant patients was high, and which was in relation to the successful clinical success criteria and sEMG findings. PMID:26465146

  9. Methotrexate pharmacotherapy for implant-related temporomandibular joint pain: a case report.

    PubMed

    Edwards, J Paul; Peterson, Erik J; Durham, Justin; Nixdorf, Donald R

    2014-08-01

    This article presents a patient experiencing several years of pain associated with bilateral failed temporomandibular joint (TMJ) Proplast/Teflon fossa prostheses. Despite surgical removal of the prostheses and comprehensive conservative management, including typical pharmacotherapy approaches for chronic pain, pain was still not relieved, and management was revised to target a putative chronic inflammatory disorder. Methotrexate was prescribed because of its known efficacy for inflammation and pain reduction in rheumatoid arthritis. Titration of methotrexate dosage over 5 months to a weekly dose of 20 mg resulted in reduced pain intensity at rest, increased pain-free maximal jaw opening, and a reduction in the sensory component of the McGill Pain Questionnaire. Maximum assisted jaw opening remained the same, as did the palpation tenderness of both TMJs and of the masseter and temporalis muscles. Methotrexate pharmacotherapy may represent a viable option when conservative treatments have failed to provide significant pain relief in patients who have had Proplast/Teflon TMJ implants. PMID:25047933

  10. Caramel as a Model System for Evaluating the Roles of Mechanical Properties and Oral Processing on Sensory Perception of Texture.

    PubMed

    Wagoner, Ty B; Luck, Paige J; Foegeding, E Allen

    2016-03-01

    Food formulation can have a significant impact on texture perception during oral processing. We hypothesized that slight modifications to caramel formulations would significantly alter mechanical and masticatory parameters, which can be used to explain differences in texture perception. A multidisciplinary approach was applied by evaluating relationships among mechanical properties, sensory texture, and oral processing. Caramels were utilized as a highly adhesive and cohesive model system and the formulation was adjusted to generate distinct differences in sensory hardness and adhesiveness. Descriptive analysis was used to determine sensory texture, and mechanical properties were evaluated by oscillatory rheology, creep recovery, and pressure sensitive tack measurements. Oral processing was measured by determining activity of anterior temporalis and masseter muscles via electromyography and tracking jaw movement during chewing. The substitution of agar or gelatin for corn syrup at 0.6% w/w of the total formulation resulted in increased sensory hardness and decreased adhesiveness. Creep recovery and pressure sensitive tack testing were more effective at differentiating among treatments than oscillatory rheology. Hardness correlated inversely with creep compliance, and both stickiness and tooth adhesiveness correlated with pressure sensitive adhesive force. Harder samples, despite being less adhesive, were associated with increased muscle activity and jaw movement during mastication. Tooth packing, not linked with any mechanical property, correlated with altered jaw movement. The combination of material properties and oral processing parameters were able to explain all sensory texture differences in a highly adhesive food. PMID:26823092

  11. High resolution bone material property assignment yields robust subject specific finite element models of complex thin bone structures.

    PubMed

    Pakdel, Amirreza; Fialkov, Jeffrey; Whyne, Cari M

    2016-06-14

    Accurate finite element (FE) modeling of complex skeletal anatomy requires high resolution in both meshing and the heterogeneous mapping of material properties onto the generated mesh. This study introduces Node-based elastic Modulus Assignment with Partial-volume correction (NMAP) as a new approach for FE material property assignment to thin bone structures. The NMAP approach incorporates point spread function based deblurring of CT images, partial-volume correction of CT image voxel intensities and anisotropic interpolation and mapping of CT intensity assignment to FE mesh nodes. The NMAP procedure combined with a derived craniomaxillo-facial skeleton (CMFS) specific density-isotropic elastic modulus relationship was applied to produce specimen-specific FE models of 6 cadaveric heads. The NMAP procedure successfully generated models of the complex thin bone structures with surface elastic moduli reflective of cortical bone material properties. The specimen-specific CMFS FE models were able to accurately predict experimental strains measured under in vitro temporalis and masseter muscle loading (r=0.93, slope=1.01, n=5). The strength of this correlation represents a robust validation for CMFS FE modeling that can be used to better understand load transfer in this complex musculoskeletal system. The developed methodology offers a systematic process-flow able to address the complexity of the CMFS that can be further applied to create high-fidelity models of any musculoskeletal anatomy. PMID:27033728

  12. Tetanus: pathophysiology, treatment, and the possibility of using botulinum toxin against tetanus-induced rigidity and spasms.

    PubMed

    Hassel, Bjørnar

    2013-01-01

    Tetanus toxin, the product of Clostridium tetani, is the cause of tetanus symptoms. Tetanus toxin is taken up into terminals of lower motor neurons and transported axonally to the spinal cord and/or brainstem. Here the toxin moves trans-synaptically into inhibitory nerve terminals, where vesicular release of inhibitory neurotransmitters becomes blocked, leading to disinhibition of lower motor neurons. Muscle rigidity and spasms ensue, often manifesting as trismus/lockjaw, dysphagia, opistotonus, or rigidity and spasms of respiratory, laryngeal, and abdominal muscles, which may cause respiratory failure. Botulinum toxin, in contrast, largely remains in lower motor neuron terminals, inhibiting acetylcholine release and muscle activity. Therefore, botulinum toxin may reduce tetanus symptoms. Trismus may be treated with botulinum toxin injections into the masseter and temporalis muscles. This should probably be done early in the course of tetanus to reduce the risk of pulmonary aspiration, involuntary tongue biting, anorexia and dental caries. Other muscle groups are also amenable to botulinum toxin treatment. Six tetanus patients have been successfully treated with botulinum toxin A. This review discusses the use of botulinum toxin for tetanus in the context of the pathophysiology, symptomatology, and medical treatment of Clostridium tetani infection. PMID:23299659

  13. Static balancing behaviour of the mandible.

    PubMed

    Hellmann, Daniel; Brüstle, Fabian; Terebesi, Sophia; Giannakopoulos, Nikolaos N; Eberhard, Lydia; Rammelsberg, Peter; Schindler, Hans J

    2015-12-01

    The objective of this study was to investigate the mechanisms of physiological control of the craniomandibular system during force-controlled biting: in intercuspation, restricted by predetermined anatomic-geometrical conditions [i.e. biting in intercuspation (BIC)]; and on a hydrostatic system [i.e. auto-balanced static equilibrium of the mandible (BAL)], in which the mandible is balanced under unrestricted occlusal conditions. For 20 healthy subjects, the spatial positions of the condyles, the lower molars, and the incisal point were measured, and the electromyographic (EMG) activity of the musculus masseter and musculus temporalis anterior were recorded bilaterally, during force-controlled biting (50, 75, 100 N) on a hydrostatic device. The results were compared with those obtained during BIC. During BAL, the neuromuscular system stabilizes one condyle, so it behaves as a virtual fulcrum, and all available biomechanical degrees of freedom of the opposite side are used to achieve a bilaterally equal vertical distance between the upper and lower dental arches. The variability of the positions of the molars was significantly smaller than for the condyles. The EMG co-contraction ratios calculated for homonymous muscle regions revealed significant differences between BIC and BAL, specifically, greater symmetry during BAL with substantial asymmetry of approximately 25% remaining. In conclusion, the results revealed precise neuromuscular control of the position of the lower dental arch; this information might form the basis for interference-free tracking of the mandible in intercuspation under different conditions. PMID:26446049

  14. Effects of prolonged gum chewing on pain and fatigue in human jaw muscles.

    PubMed

    Farella, M; Bakke, M; Michelotti, A; Martina, R

    2001-04-01

    Gum chewing has been accepted as an adjunct to oral hygiene, as salivary stimulant and vehicle for various agents, as well as for jaw muscle training. The aim of this study was to investigate the effects of prolonged gum chewing on pain, fatigue and pressure tenderness of the masticatory muscles. Fifteen women without temporomandibular disorders (TMD) were requested to perform one of the following chewing tasks in three separate sessions: chewing a very hard gum, chewing a soft gum, and empty-chewing with no bolus. Unilateral chewing of gum or empty chewing was performed for 40 min at a constant rate of 80 cycles/min. In each session, perceived muscle pain and masticatory fatigue were rated on visual analog scales (VAS) before, throughout, and after the chewing task. Pressure pain thresholds (PPTs) of masseter and anterior temporalis muscles were assessed before and immediately after the chewing tasks, and again after 24 h. The VAS scores for pain and fatigue significantly increased only during the hard gum chewing, and after 10 min of recovery VAS scores had decreased again, almost to their baseline values. No significant changes were found for PPTs either after hard or soft gum chewing. The findings indicate that the jaw muscles recover quickly from prolonged chewing activity in subjects without TMD. PMID:11347660

  15. An investigation on the simultaneously recorded occlusion contact and surface electromyographic activity for patients with unilateral temporomandibular disorders pain.

    PubMed

    Li, Bao-Yong; Zhou, Li-Juan; Guo, Shao-Xiong; Zhang, Yuan; Lu, Lei; Wang, Mei-Qing

    2016-06-01

    The present study examined if unilateral pain from temporomandibular disorders (TMD) was associated with the occlusion contacts and surface electromyographic (SEMG) activities of jaw-closing muscles. Eleven patients with unilateral TMD pain and 20 healthy volunteers who all had Angle's Class-I occlusions were enrolled. The numbers and load distributions of the occlusion contacts and the SEMG activities of the anterior temporalis (TA) muscles and masseters muscles (MM) during maximal voluntary clenching (MVC) in the centric and eccentric positions were simultaneously recorded on both sides. The pain was not associated with occlusal contact numbers or load distributions. The SEMG activities of the pain-side TA and bilateral MM were lower during centric MVC compared with controls. The SEMG activities of the non-pain-side TA and the normalized SEMG activities of the bilateral TAs and MMs were higher during protrusive MVC (p<0.05). During pain-side MVC, the normalized SEMG activities of the working-side MM and balancing-side TA were higher than those of the controls. In conclusion, the TMD pain side was not associated with the occlusal contacts, but the patients with TMD had TA and MM SEMG activities during different tasks that differed from controls and that did not seem related to the pain side. PMID:26643794

  16. Sensitivity analysis of a validated subject-specific finite element model of the human craniofacial skeleton.

    PubMed

    Szwedowski, T D; Fialkov, J; Whyne, C M

    2011-01-01

    Developing a more complete understanding of the mechanical response of the craniofacial skeleton (CFS) to physiological loads is fundamental to improving treatment for traumatic injuries, reconstruction due to neoplasia, and deformities. Characterization of the biomechanics of the CFS is challenging due to its highly complex structure and heterogeneity, motivating the utilization of experimentally validated computational models. As such, the objective of this study was to develop, experimentally validate, and parametrically analyse a patient-specific finite element (FE) model of the CFS to elucidate a better understanding of the factors that are of intrinsic importance to the skeletal structural behaviour of the human CFS. An FE model of a cadaveric craniofacial skeleton was created from subject-specific computed tomography data. The model was validated based on bone strain measurements taken under simulated physiological-like loading through the masseter and temporalis muscles (which are responsible for the majority of craniofacial physiologic loading due to mastication). The baseline subject-specific model using locally defined cortical bone thicknesses produced the strongest correlation to the experimental data (r2 = 0.73). Large effects on strain patterns arising from small parametric changes in cortical thickness suggest that the very thin bony structures present in the CFS are crucial to characterizing the local load distribution in the CFS accurately. PMID:21381488

  17. A new biomechanical model for evaluation of fixation systems of maxillofacial fractures.

    PubMed

    Ji, Baohui; Wang, Chun; Song, Fumin; Chen, Mengshi; Wang, Hang

    2012-07-01

    The aim of this study was to develop a new type of biomechanical model for biomechanical researches of maxillofacial fractures and then evaluate it. Twenty synthetic polyurethane maxillary and mandibular models were used to simulate the mandible and maxilla. Springs were used to represent the forces of masseter, medial pterygoid, temporalis, and lateral pterygoid muscles acting on the models. Four masticatory conditions, namely clenching in the intercuspal position (ICP), incisal clenching (INC), left unilateral molar clenching (L-MOL, contralateral side of fracture) and right unilateral molar clenching (R-MOL, fracture side) were simulated. The strain on a miniplates placed across a simulated fracture was measured using strain gauges attached to the plate surface. During INC and L-MOL, the strain on the miniplates confirmed the findings of Champy. The upper miniplate was subjected to tension force and the lower miniplate to compression. When the bite point moved to the fracture, the tension-compression zone reversed, with the upper miniplate relatively compressed and the lower miniplate tension. During ICP, the tension-compression zone changed again, with both miniplates tension. In conclusion, we have successfully developed a model which is much closer to physiological conditions than models used previously. It is reliable and useful for biomechanical tests of mandibular fractures. Models including soft tissue need developing to further understand fracture healing biomechanics. PMID:21865052

  18. Conservative gap arthroplasty in temporomandibular ankylosis not involving the sigmoid notch: a selected age group study.

    PubMed

    Temerek, Ahmed Talaat

    2016-06-01

    In this prospective, cohort, clinical follow-up study we aimed to investigate the role of conservative gap arthroplasty without interpositional material in managing ankylosis of the temporomandibular joint (TMJ). Thirteen patients (15 joints) with ankylosis who fulfilled the other inclusion criteria were enrolled. The ankylotic mass was excised to create a gap of 7-9mm. No interpositional material was used. Ipsilateral or bilateral masseter reflection, pterygomasseteric sling, and temporalis tendon release plus coronoidectomy were considered if maximum mouth opening failed to reach 35mm. A physiotherapy protocol was started on the first day. Patients' ages ranged from 13-38 (mean (SD) 18 (7) years). Trauma was the main cause. Duration of ankylosis at presentation ranged from 1-17 years (mean (SD) 5 (4) years). Eleven patients had unilateral, and two bilateral, ankylosis that did not involve the sigmoid notch. The mean (SD) maximum incisal opening (mm) was 38 (4) two years' postoperatively. The facial nerve was affected temporarily in two patients. Mean (SD) duration of follow-up was 4 (2) years without recurrence. Within our selection criteria, conservative gap arthroplasty of 7-9mm without interpositional material and with vigorous postoperative physiotherapy has a role in treating ankylosis of the TMJ and preventing its recurrence for more than four years. PMID:26972420

  19. Oral Health, Temporomandibular Disorder, and Masticatory Performance in Patients with Charcot-Marie-Tooth Type 2

    PubMed Central

    Rezende, Rejane L. S.; Bonjardim, Leonardo R.; Neves, Eduardo L. A.; Santos, Lidiane C. L.; Nunes, Paula S.; Garcez, Catarina A.; Souza, Cynthia C.; Araújo, Adriano A. S.

    2013-01-01

    Background. The aim of this study was to evaluate the oral health status of temporomandibular disorders (TMD) and bruxism, as well as to measure masticatory performance of subjects with Charcot-Marie-Tooth type 2 (CMT2). Methods and Results. The average number of decayed, missing, and filled teeth (DMFT) for both groups, control (CG) and CMT2, was considered low (CG = 2.46; CMT2 = 1.85, P = 0.227). The OHIP-14 score was considered low (CG = 2.86, CMT2 = 5.83, P = 0.899). The prevalence of self-reported TMD was 33.3% and 38.9% (P = 0.718) in CG and CMT2 respectively and for self-reported bruxism was 4.8% (CG) and 22.2% (CMT2), without significant difference between groups (P = 0.162). The most common clinical sign of TMD was masseter (CG = 38.1%; CMT2 = 66.7%) and temporalis (CG = 19.0%; GCMT2 = 33.3%) muscle pain. The geometric mean diameter (GMD) was not significantly different between groups (CG = 4369; CMT2 = 4627, P = 0.157). Conclusion. We conclude that the CMT2 disease did not negatively have influence either on oral health status in the presence and severity of TMD and bruxism or on masticatory performance. PMID:24391462

  20. Predicting bite force in mammals: two-dimensional versus three-dimensional lever models.

    PubMed

    Davis, J L; Santana, S E; Dumont, E R; Grosse, I R

    2010-06-01

    Bite force is a measure of whole-organism performance that is often used to investigate the relationships between performance, morphology and fitness. When in vivo measurements of bite force are unavailable, researchers often turn to lever models to predict bite forces. This study demonstrates that bite force predictions based on two-dimensional (2-D) lever models can be improved by including three-dimensional (3-D) geometry and realistic physiological cross-sectional areas derived from dissections. Widely used, the 2-D method does a reasonable job of predicting bite force. However, it does so by over predicting physiological cross-sectional areas for the masseter and pterygoid muscles and under predicting physiological cross-sectional areas for the temporalis muscle. We found that lever models that include the three dimensional structure of the skull and mandible and physiological cross-sectional areas calculated from dissected muscles provide the best predictions of bite force. Models that accurately represent the biting mechanics strengthen our understanding of which variables are functionally relevant and how they are relevant to feeding performance. PMID:20472771

  1. The effect of flexible acrylic resin on masticatory muscle activity in implant-supported mandibular overdentures: a controlled clinical trial

    PubMed Central

    Ibraheem, Eman Mostafa Ahmed; Nassani, Mohammad Zakaria

    2016-01-01

    Background It is not yet clear from the current literature to what extent masticatory muscle activity is affected by the use of flexible acrylic resin in the construction of implant-supported mandibular overdentures. Objective To compare masticatory muscle activity between patients who were provided with implant-supported mandibular overdentures constructed from flexible acrylic resin and those who were provided with implant-supported mandibular overdentures constructed from heat-cured conventional acrylic resin. Methods In this clinical trial, 12 completely edentulous patients were selected and randomly allocated into two equal treatment groups. Each patient in Group 1 received two implants to support a mandibular overdenture made of conventional acrylic resin. In Group 2, the patients received two implants to support mandibular overdentures constructed from “Versacryl” flexible acrylic resin. The maxillary edentulous arch for patients in both groups was restored by conventional complete dentures. For all patients, masseter and temporalis muscle activity was evaluated using surface electromyography (sEMG). Results The results showed a significant decrease in masticatory muscle activity among patients with implant-supported mandibular overdentures constructed from flexible acrylic resin. Conclusion The use of “Versacryl” flexible acrylic resin in the construction of implant-supported mandibular overdentures resulted in decreased masticatory muscle activity. PMID:26955445

  2. Effect of experimental chewing on masticatory muscle pain onset

    PubMed Central

    CONTI, Paulo César Rodrigues; SILVA, Rafael dos Santos; de ARAUJO, Carlos dos Reis Pereira; ROSSETI, Leylha Maria N.; YASSUDA, Shigueharu; da SILVA, Renato Oliveira Ferreira; PEGORARO, Luiz Fernando

    2011-01-01

    Objectives To evaluate the effect of a chewing exercise on pain intensity and pressurepain threshold in patients with myofascial pain. Methods Twenty-nine consecutive women diagnosed with myofascial pain (MFP) according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS) every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT) was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. Results Patients with myofascial pain reported increase (76%) and no change (24%) on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. Conclusion The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls. PMID:21437467

  3. Tetanus: Pathophysiology, Treatment, and the Possibility of Using Botulinum Toxin against Tetanus-Induced Rigidity and Spasms

    PubMed Central

    Hassel, Bjørnar

    2013-01-01

    Tetanus toxin, the product of Clostridium tetani, is the cause of tetanus symptoms. Tetanus toxin is taken up into terminals of lower motor neurons and transported axonally to the spinal cord and/or brainstem. Here the toxin moves trans-synaptically into inhibitory nerve terminals, where vesicular release of inhibitory neurotransmitters becomes blocked, leading to disinhibition of lower motor neurons. Muscle rigidity and spasms ensue, often manifesting as trismus/lockjaw, dysphagia, opistotonus, or rigidity and spasms of respiratory, laryngeal, and abdominal muscles, which may cause respiratory failure. Botulinum toxin, in contrast, largely remains in lower motor neuron terminals, inhibiting acetylcholine release and muscle activity. Therefore, botulinum toxin may reduce tetanus symptoms. Trismus may be treated with botulinum toxin injections into the masseter and temporalis muscles. This should probably be done early in the course of tetanus to reduce the risk of pulmonary aspiration, involuntary tongue biting, anorexia and dental caries. Other muscle groups are also amenable to botulinum toxin treatment. Six tetanus patients have been successfully treated with botulinum toxin A. This review discusses the use of botulinum toxin for tetanus in the context of the pathophysiology, symptomatology, and medical treatment of Clostridium tetani infection. PMID:23299659

  4. "Bochdalek's" skull: morphology report and reconstruction of face.

    PubMed

    Klepáček, Ivo; Malá, Pavla Zedníková

    2012-12-01

    The objective of this study was to create a real model of a face using the well preserved "Bochdalek's skull" (from an eighteenth Century female aged 18 years) kept in the museum of anatomy (Institute of Anatomy, 1st Medical Faculty, Charles University in Prague). The skull had previously been appraised as a deformed skull with an adhesion present on both sides of the jaw, most likely of post-traumatic origin (bilateral syngnathia). In an attempt to find the best description for it, and to identify the spatial relationships between the surface of the facial bones which had changed in shape, as well as the formation of soft tissue on the face, we decided to perform a 3D reconstruction of the face. Due to the necessity of preserving the unique original undamaged skull, we created an exact digital "casting" of the facial bone structure on a computer first, which we then converted into a three-dimensional model using a 3D RepRap printer. We needed to take into consideration the fact that we had no portrait of the girl, just the skull. For this reason, we opted for a selected combination of anthropologic steps (the modified Manchester technique), which in our view, allows for optimum creation of the topography of the face in keeping with the deformed skull. The resulting reconstructed face was old in appearance with an overhanging lower lip and flattened surfaces in the areas of the temporalis and masseter muscles. PMID:22918853

  5. Electromyography of swallowing with fine wire intramuscular electrodes in healthy human: activation sequence of selected hyoid muscles.

    PubMed

    Inokuchi, Haruhi; González-Fernández, Marlís; Matsuo, Koichiro; Brodsky, Martin B; Yoda, Mitsumasa; Taniguchi, Hiroshige; Okazaki, Hideto; Hiraoka, Takashi; Palmer, Jeffrey B

    2014-12-01

    Few studies have reported the activation sequence of the swallowing muscles in healthy human participants. We examined temporal characteristics of selected hyoid muscles using fine wire intramuscular electromyography (EMG). Thirteen healthy adults were studied using EMG of the anterior belly of digastric (ABD), geniohyoid (GH), sternohyoid (SH), and masseter (MA, with surface electrodes) while ingesting thin liquid, banana, tofu, and cookie (3 trials each). Onset timing was measured from rectified and integrated EMG. Data were analyzed using repeated-measures ANOVA with Bonferroni correction. When drinking thin liquid, MA, GH, and ABD were activated almost simultaneously, but SH was activated later (using GH onset as 0 s, MA -0.07 (-0.20 to 0.17) second [median (interquartile range)]; ABD 0.00 (-0.10 to 0.07) second; SH 0.17 (0.02 to 0.37) second; P < 0.01). With solid foods, MA contraction preceded GH and ABD; SH was last and delayed relative to liquid swallows (GH 0 s; MA -0.17 (-0.27 to 0.07) second; ABD 0.00 (-0.03 to 0.03) second; SH 0.37 (0.23 to 0.50) second; P < 0.01). The role of the MA differs between solids and liquids so the variation in its timing is expected. The synchronous contraction of GH and ABD was consistent with their role in hyolaryngeal elevation. The SH contracted later with solids, perhaps because if the longer duration of the swallow. The consistent pattern among foods supports the concept of a central pattern generator for pharyngeal swallowing. PMID:25142242

  6. P2X and NMDA receptor involvement in temporomandibular joint-evoked reflex activity in rat jaw muscles.

    PubMed

    Watanabe, T; Tsuboi, Y; Sessle, B J; Iwata, K; Hu, J W

    2010-07-30

    We have previously shown that injection of the excitatory amino glutamate into the rat temporomandibular joint (TMJ) evokes reflex activity in both anterior digastric (DIG) and masseter (MASS) muscles that can be attenuated by prior TMJ injection of an N-methyl-d-aspartate (NMDA) receptor antagonist. The aim of the present study was to test if jaw muscle activity could also be evoked by P2X receptor agonist injection into the rat TMJ region and if the reflex activity could be modulated by TMJ injection of P2X receptor antagonist or NMDA receptor antagonist. The selective P2X subtype agonist alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-me ATP) and vehicle (phosphate-buffered saline) or the selective P2X antagonist, 2'-(or-3')-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP) or the selective NMDA antagonist (+/-)-d-2-amino-5-phosphonovalerate(APV) were injected into the rat TMJ region. Electromyographic (EMG) reflex activity was recorded in both DIG and MASS muscles. Compared with the baseline EMG activity, alpha,beta-me-ATP injection into the TMJ (but not its systemic administration) following pre-injection of the vehicle significantly increased the magnitude and the duration of ipsilateral DIG and MASS EMG activity in a dose-dependent manner. The alpha,beta-me-ATP-evoked responses could be antagonized by pre-injection of TNP-ATP into the same TMJ site but contralateral TMJ injection of TNP-ATP proved ineffective. Furthermore, the alpha,beta-me-ATP-evoked responses could also be antagonized by APV injected into the same TMJ site but not by its systemic injection. These results indicate the interaction of peripheral purinergic as well as glutamatergic receptor mechanisms in the processing of TMJ nociceptive afferent inputs that evoke reflex activity in jaw muscles. PMID:20501327

  7. Fusimotor influence on jaw muscle spindle activity during swallowing-related movements in the cat.

    PubMed Central

    Taylor, A; Hidaka, O; Durbaba, R; Ellaway, P H

    1997-01-01

    1. The activity patterns of muscle spindle afferents in jaw-closer muscles were studied during reflex swallowing movements in anaesthetized cats. Simultaneous records were made of the electromyogram (EMG) in masseter and anterior digastric muscles and of the unloaded jaw movements. The underlying patterns of fusimotor activity were deduced by comparing afferent discharges occurring during active swallowing with those occurring when exactly the same movements were imposed passively. The interpretation of spindle behaviour was greatly facilitated by characterizing the afferents according to the evidence for their contact with the various intrafusal muscle fibres, derived from testing with succinylcholine. It was also valuable to have two different types of afferent recorded simultaneously. 2. There was clear evidence of fusimotor activity occurring during active jaw closing so as to oppose the spindle silencing. This effect was most marked in b2c-type afferents (probably secondaries) and was therefore attributed to a modulation of static fusimotor discharge approximately in parallel with alpha-activity. 3. Afferents with evidence of bag1 fibre contacts (primaries) showed much greater sensitivity to muscle lengthening during active movement than when the movement was imposed. This difference was exaggerated when anaesthesia was deepened for the passive movements. This was interpreted as evidence for a higher level of dynamic fusimotor activity maintained during active movements than at rest. 4. The results support the view that for a variety of active jaw movements, static fusimotor neurone firing is modulated roughly in parallel with alpha-activity but leading it so as to counteract spindle unloading. Dynamic fusimotor neurone firing appears to be set at a raised level during active movements. Anaesthesia appears to depress activity in the alpha-motoneurones more than in gamma-motoneurones. PMID:9288683

  8. Systemic Pregabalin Attenuates Sensorimotor Responses and Medullary Glutamate Release in Inflammatory Tooth Pain Model

    PubMed Central

    Narita, Noriyuki; Kumar, Naresh; Cherkas, Pavel S.; Chiang, Chen Yu; Dostrovsky, Jonathan O.; Coderre, Terence J.; Sessle, Barry J.

    2012-01-01

    Our previous studies have demonstrated that application to the tooth pulp of the inflammatory irritant mustard oil (MO) induces medullary glutamate release and central sensitization in the rat medullary dorsal horn (MDH), as well as nociceptive sensorimotor responses in craniofacial muscles in rats. There is recent evidence that anticonvulsant drugs such as pregabalin that influence glutamatergic neurotransmission are effective in several pain states. The aim of this study was to examine whether systemic administration of pregabalin attenuated glutamate release in the medulla as well as these nociceptive effects reflected in increased electromyographic (EMG) activity induced by MO application to the tooth pulp. Male adult rats were anesthetized with isofluorane (1.0~1.2 %), and jaw and tongue muscle EMG activities were recorded by needle electrodes inserted bilaterally into masseter and anterior digastric muscles and into the genioglossus muscle, and also the medullary release of glutamate was assessed by in vivo microdialysis. Pregabalin or vehicle control (isotonic saline) was administered 30 min before the pulpal application of MO or vehicle control (mineral oil). Application of mineral oil to the maxillary first molar tooth pulp produced no change in baseline EMG activity and glutamate release. However, application of MO to the pulp significantly increased both the medullary release of glutamate and EMG activity in the jaw and tongue muscles for several minutes. In contrast, pre-medication with pregabalin, but not vehicle control, significantly and dose-dependently attenuated the medullary glutamate release and EMG activity in these muscles after MO application to the tooth pulp (ANOVA, p<0.05). These results suggest that pregabalin may attenuate the medullary release of glutamate and associated nociceptive sensorimotor responses in this acute inflammatory pulpal pain model, and that it may prove useful for the treatment of orofacial inflammatory pain states

  9. Computed tomography and magnetic resonance diagnosis of variations in the anatomical location of the major salivary glands in 1680 dogs and 187 cats.

    PubMed

    Durand, A; Finck, M; Sullivan, M; Hammond, G

    2016-03-01

    During assessment of routine clinical magnetic resonance imaging (MRI) of the heads of dogs, variations in the location of mandibular and zygomatic salivary glands (SGs) were observed incidentally. The aims of this retrospective study were to describe anatomical variations of the major SGs found on MRI and computed tomography (CT) studies of the head in dogs and cats and to investigate possible clinical relevancy. No anatomical variation of the SGs was seen in cats, but in dogs, although variation of the parotid SG was not identified, that of the mandibular SG was found in 33/1680 animals (2%), either unilaterally (6/33 right-sided, 13/33 left-sided) or bilaterally (14/33). The Border terrier breed (19/33, 58%) was over-represented. Each atypically located mandibular SG was positioned medial to the digastric muscle and rostral to the retropharyngeal lymph node. The sublingual glands were difficult to delineate from the mandibular glands. Anatomical variation of one zygomatic gland (3/4 left-sided) was identified in four small-breed dogs (0.2%). Each atypically located zygomatic gland was tilted at the ventrorostral aspect of the masseter muscle underneath the skin surface. MRI and CT characteristics were not different between typically and atypically located SGs. None of the dogs had clinical signs related with SG disease. It was concluded that, with suspected breed predispositions, incidental unilateral or bilateral anatomical variations of mandibular and zygomatic SGs can be encountered in dogs and an awareness of these possible variations may be important in pre-surgical planning. PMID:26832809

  10. Systemic pregabalin attenuates sensorimotor responses and medullary glutamate release in inflammatory tooth pain model.

    PubMed

    Narita, N; Kumar, N; Cherkas, P S; Chiang, C Y; Dostrovsky, J O; Coderre, T J; Sessle, B J

    2012-08-30

    Our previous studies have demonstrated that application of inflammatory irritant mustard oil (MO) to the tooth pulp induces medullary glutamate release and central sensitization in the rat medullary dorsal horn (MDH), as well as nociceptive sensorimotor responses in craniofacial muscles in rats. There is recent evidence that anticonvulsant drugs such as pregabalin that influence glutamatergic neurotransmission are effective in several pain states. The aim of this study was to examine whether systemic administration of pregabalin attenuated glutamate release in the medulla as well as these nociceptive effects reflected in increased electromyographic (EMG) activity induced by MO application to the tooth pulp. Male adult rats were anesthetized with isofluorane (1.0-1.2%), and jaw and tongue muscle EMG activities were recorded by needle electrodes inserted bilaterally into masseter and anterior digastric muscles and into the genioglossus muscle, and also the medullary release of glutamate was assessed by in vivo microdialysis. Pregabalin or vehicle control (isotonic saline) was administered 30 min before the pulpal application of MO or vehicle control (mineral oil). Application of mineral oil to the maxillary first molar tooth pulp produced no change in baseline EMG activity and glutamate release. However, application of MO to the pulp significantly increased both the medullary release of glutamate and EMG activity in the jaw and tongue muscles for several minutes. In contrast, pre-medication with pregabalin, but not vehicle control, significantly and dose-dependently attenuated the medullary glutamate release and EMG activity in these muscles after MO application to the tooth pulp (analysis of variance (ANOVA), p<0.05). These results suggest that pregabalin may attenuate the medullary release of glutamate and associated nociceptive sensorimotor responses in this acute inflammatory pulpal pain model, and that it may prove useful for the treatment of orofacial

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

    PubMed

    Augusti, Davide; Augusti, Gabriele; Re, Dino; Dellavia, Claudia; Giannì, Aldo Bruno

    2015-08-01

    This study evaluated the influence of two different occlusal indicators (articulating papers of 40μm and 200μm) on muscular activity of the temporalis anterior (TA) and superficial masseter (MS) during maximum voluntary clenches (MVC), using surface electromyography (SEMG). It was hypothesized that an articulating paper positioned between dental arches during MVC elicits a different muscular activity compared with the occlusion on natural dentition (without the occlusal indicator). 30 healthy adult subjects with a complete, natural dentition were recruited; SEMG activity was recorded in the following experimental conditions: MVC with cotton rolls for standardization purposes; MVC on natural dentition; MVC onto the 40μm or 200μm paper indicator positioned on right or left side of the dental arch. Percentage Overlapping Coefficient (POC; separate values obtained for TA and MS), antero-posterior coefficient (APC) and total muscle activities (IMP) were the analyzed SEMG parameters. The use of an occlusal indicator statistically changed POC_TA, POC_MS and IMP median values (p<0.05). Both 40μm and 200μm occlusal papers did not significantly affect APC values (P=0.86). A pronounced asymmetric muscular activity has been recorded with the introduction of an interocclusal media. All indices of muscular activity did not differ between sexes (Kruskal Wallis test, P>0.05). In conclusion, the examined articulating papers affected two specific SEMG parameters (POC and IMP); the recorded muscular activity with the occlusal indicator varied regardless left or right side positioning, and independently from tested paper thicknesses. PMID:25956545

  12. Cardiovascular responses in humans to experimental chewing of gums of different consistencies.

    PubMed

    Farella, M; Bakke, M; Michelotti, A; Marotta, G; Martina, R

    1999-10-01

    Although the cardiovascular effects of exercise have been extensively investigated in man, little attention has been paid to such responses to jaw muscle activity. The aim here was to investigate the general cardiovascular effects of chewing activity in a single-blind, cross-over design. Ten healthy individuals performed one of the following chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a bolus. Unilateral chewing of gum or empty chewing was performed for 20 min on the participant's most convenient chewing side at a constant rate of 80 cycles/min. In each session, heart rate and arterial blood pressure were recorded together with electromyographic activity in the masseter and anterior temporalis muscles on the chewing side. Ratings of perceived masticatory fatigue were recorded with visual analogue scales. The heart rate and blood pressure were significantly increased (ANOVA; p < or= 0.01) during the chewing tasks and the increases were, in parallel with the muscle activity, more pronounced the harder the gum. With the very hard gum, heart rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was 11 mmHg (1.5kPa) higher. The perceived fatigue was proportional to the level of muscle activity. After 10 min of recovery from exercise, heart rate and arterial blood pressures were slightly but still significantly elevated. The results demonstrate that chewing is associated with general circulatory effects proportional to the bolus resistance. PMID:10530916

  13. Prevalence of signs and symptoms of craniomandibular disorders and orofacial parafunction in 4-6-year-old African-American and Caucasian children.

    PubMed

    Widmalm, S E; Christiansen, R L; Gunn, S M; Hawley, L M

    1995-02-01

    Children, 4-6 years old, 153 Caucasian and 50 African-American, from a pre-school and kindergarten programme in a low income industrial area, who participated in a voluntary oral health examination, were questioned and examined for signs and symptoms of craniomandibular disorders (CMD) and of oral parafunctions. Most of the CMD signs and symptoms were mild. Eight per cent had recurrent (at least 1-2 times per week) TMJ pain, and 5% had recurrent neck pain, African-American children more often than Caucasian children (P < 0.05). Seventeen per cent had recurrent headache. Three per cent had recurrent earache. Pain or tiredness in the jaws during chewing was reported by 25% of the children, more often by African-American than by Caucasian children (P < 0.001) and more often by girls than by boys (P < 0.05). Pain at jaw opening occurred in 10% of the children, more often in the African-American than in the Caucasian group (P < 0.001). Thirteen per cent of the children had problems in opening the mouth. Deviation during opening was observed in 17% and reduced opening in 2%. Reduced lateral movements, locking or luxation were not observed in any child. Palpation pain was found in the lateral TMJ area in 16%, in the posterior TMJ area in 25%, in the temporalis and masseter areas in 10%, and pain for all regions was found more often in the African-American than in the Caucasian children (P < 0.01). Thirty-four per cent of the African-American, and 15% of the Caucasian children admitted to having ear noises (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7722749

  14. Can masticatory electromyography be normalised to submaximal bite force?

    PubMed

    Crawford, S R; Burden, A M; Yates, J M; Zioupos, P; Winwood, K

    2015-05-01

    The combination of bite force and jaw muscle electromyography (EMG) provides an insight into the performance of the stomatognathic system, especially in relation to dynamic movement tasks. Literature has extensively investigated possible methods for normalising EMG data encapsulating many different approaches. However, bite force literature trends towards normalising EMG to a maximal voluntary contraction (MVC), which could be difficult for ageing populations or those with poor dental health or limiting conditions such as temporomandibular disorder. The objectives of this study were to (i) determine whether jaw-closing muscle activity is linearly correlated with incremental submaximal and maximal bite force levels and (ii) assess whether normalising maximal and submaximal muscle activity to that produced when performing a low submaximal bite force (20 N) improves repeatability of EMG values. Thirty healthy adults (15 men, 15 women; mean age 21 ± 1·2 years) had bite force measurements obtained using a custom-made button strain gauge load cell. Masseter and anterior temporalis muscle activities were collected bilaterally using surface EMG sensors whilst participants performed maximal biting and three levels of submaximal biting. Furthermore, a small group (n = 4 females) were retested for reliability purposes. Coefficients of variation and intra-class correlation coefficients showed markedly improved reliability when EMG data were normalised compared to non-normalised. This study shows that jaw muscle EMG may be successfully normalised to a very low bite force. This may open possibilities for comparisons between at-risk sample groups that may otherwise find it difficult to produce maximal bite force values. PMID:25600826

  15. Involvement of trigeminal subnucleus caudalis (medullary dorsal horn) in craniofacial nociceptive reflex activity.

    PubMed

    Tsai, C M; Chiang, C Y; Yu, X M; Sessle, B J

    1999-05-01

    We have previously shown that an increase in electromyographic (EMG) activity of digastric (DIG) and masseter (MASS) muscles can be reflexly evoked by injection into the rat's temporomandibular joint (TMJ) region of the small-fibre excitant and inflammatory irritant mustard oil (MO). Since the trigeminal (V) subnucleus caudalis (Vc, i.e. medullary dorsal horn) has traditionally been viewed as an essential brainstem relay site of nociceptive information from craniofacial tissues, an EMG study was carried out in 45 anaesthetized rats to determine if Vc is involved in the MO-evoked increases in jaw muscle EMG activity. The effects of histologically confirmed surgical or chemical lesions of Vc on this evoked EMG activity were tested in different groups of rats. MO injection into the left TMJ region of intact rats evoked bilateral increases in EMG activity of DIG and MASS which could be significantly reduced by surgical transection of the left caudal brainstem at the obex level; MO injection into the right TMJ region in these same rats still readily evoked increases in EMG activity. A sagittal section medial to Vc or transection at the level of the second cervical spinal segment did not produce any significant reduction in the reflexly evoked EMG activity. Neurones in Vc, as opposed to fibres of passage, appear to be important for the MO-evoked EMG activity, since injection into Vc of the neurotoxic chemical ibotenic acid significantly reduced the mustard oil-evoked EMG activity. The Vc also appears to play a role in the activation of contralateral V motoneurons, as evidenced by the activation of the contralateral DIG and MASS muscles by the injection of MO into the left TMJ region of intact rats and by the reduction of this evoked EMG activity in the contralateral DIG and MASS of rats with a surgical transection or ibotenic acid lesion of the left Vc. These findings suggest that Vc may be a critical element in the neural pathways underlying the reflex responses evoked

  16. Glutamate dysregulation in the trigeminal ganglion: a novel mechanism for peripheral sensitization of the craniofacial region.

    PubMed

    Laursen, J C; Cairns, B E; Dong, X D; Kumar, U; Somvanshi, R K; Arendt-Nielsen, L; Gazerani, P

    2014-01-01

    In the trigeminal ganglion (TG), satellite glial cells (SGCs) form a functional unit with neurons. It has been proposed that SGCs participate in regulating extracellular glutamate levels and that dysfunction of this SGC capacity can impact nociceptive transmission in craniofacial pain conditions. This study investigated whether SGCs release glutamate and whether elevation of TG glutamate concentration alters response properties of trigeminal afferent fibers. Immunohistochemistry was used to assess glutamate content and the expression of excitatory amino acid transporter (EAAT)1 and EAAT2 in TG sections. SGCs contained glutamate and expressed EAAT1 and EAAT2. Potassium chloride (10 mM) was used to evoke glutamate release from cultured rat SGCs treated with the EAAT1/2 inhibitor (3S)-3-[[3-[[4-(trifluoromethyl)ben zoyl]amino]phenyl]methoxy]-L-aspartic acid (TFB-TBOA) or control. Treatment with TFB-TBOA (1 and 10 μM) significantly reduced the glutamate concentration from 10.6 ± 1.1 to 5.8 ± 1.4 μM and 3.0 ± 0.8 μM, respectively (p<0.05). Electrophysiology experiments were conducted in anaesthetized rats to determine the effect of intraganglionic injections of glutamate on the response properties of ganglion neurons that innervated either the temporalis or masseter muscle. Intraganglionic injection of glutamate (500 mM, 3 μl) evoked afferent discharge and significantly reduced muscle afferent mechanical threshold. Glutamate-evoked discharge was attenuated bythe N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovalerate (APV) and increased by TFB-TBOA, whereas mechanical sensitization was only sensitive to APV. Antidromic invasion of muscle afferent fibers by electrical stimulation of the caudal brainstem (10 Hz) or local anesthesia of the brainstem with lidocaine did not alter glutamate-induced mechanical sensitization. These findings provide a novel mechanism whereby dysfunctional trigeminal SGCs could contribute to cranial muscle tenderness in

  17. Effective Botulinum Toxin Injection Guide for Treatment of Temporal Headache.

    PubMed

    Choi, You-Jin; Lee, Won-Jae; Lee, Hyung-Jin; Lee, Kang-Woo; Kim, Hee-Jin; Hu, Kyung-Seok

    2016-01-01

    This study involved an extensive analysis of published research on the morphology of the temporalis muscle in order to provide an anatomical guideline on how to distinguish the temporalis muscle and temporalis tendon by observing the surface of the patient's face. Twenty-one hemifaces of cadavers were used in this study. The temporalis muscles were dissected clearly for morphological analysis between the temporalis muscle and tendon. The posterior border of the temporalis tendon was classified into three types: in Type I the posterior border of the temporalis tendon is located in front of reference line L2 (4.8%, 1/21), in Type II it is located between reference lines L2 and L3 (85.7%, 18/21), and in Type III it is located between reference lines L3 and L4 (9.5%, 2/21). The vertical distances between the horizontal line passing through the jugale (LH) and the temporalis tendon along each of reference lines L0, L1, L2, L3, and L4 were 29.7 ± 6.8 mm, 45.0 ± 8.8 mm, 37.7 ± 11.1 mm, 42.5 ± 7.5 mm, and 32.1 ± 0.4 mm, respectively. BoNT-A should be injected into the temporalis muscle at least 45 mm vertically above the zygomatic arch. This will ensure that the muscle region is targeted and so produce the greatest clinical effect with the minimum concentration of BoNT-A. PMID:27618099

  18. Quantitative Contributions of the Muscles of the Tongue, Floor-of-Mouth, Jaw, and Velum to Tongue-to-Palate Pressure Generation

    ERIC Educational Resources Information Center

    Palmer, Phyllis M.; Jaffe, Debra M.; McCulloch, Timothy M.; Finnegan, Eileen M.; Van Daele, Douglas J.; Luschei, Erich S.

    2008-01-01

    Purpose: The purpose of this investigation was to evaluate the relationship between tongue-to-palate pressure and the electromyography (EMG) measured from the mylohyoid, anterior belly of the digastric, geniohyoid, medial pterygoid, velum, genioglossus, and intrinsic tongue muscles. Methods: Seven healthy adults performed tongue-to-palate pressure…

  19. Identification of facial nerve during parotidectomy: a combined anatomical & surgical study.

    PubMed

    Saha, Somnath; Pal, Sudipta; Sengupta, Moushumi; Chowdhury, Kanishka; Saha, Vedula Padmini; Mondal, Lopamudra

    2014-01-01

    To find out the most easily identifiable and anatomically consistent landmark for identification of facial nerve during parotid surgery. Ten cadaveric dissections and ten live parotid surgeries for different types of parotid tumours were done. Cadaveric dissection was performed in the Department of Anatomy and the surgeries were done in the Department of ENT and Head and Neck surgery of R. G. Kar Medical College of Kolkata. The distance of the facial nerve trunk from three most commonly used landmarks (viz., tympanomastoid suture, tragal pointer and posterior belly of digastric muscle) was measured in both cadaver and live patients. The ease of identification of the nerve trunk using each of the landmarks, particularly during live surgery was also assessed. The mean distance of the tympanomastoid suture from the facial nerve trunk was 3.5 mm (cadaver) and 3.87 mm (live surgery), the tragal pointer was found to be at a mean distance of 16.61 mm (cadaver) and 16.36 mm (live surgery) and in case of the posterior belly of digastric muscle it was 7.41 mm (cadaver) and 8.03 mm (live surgery). During live surgery the posterior belly of digastric was found to be the most easily identifiable landmark with a consistent anatomical relationship with the nerve trunk. The posterior belly of digastric muscle is the most easily identifiable and a very consistent landmark for facial nerve dissection during parotidectomy. When supplemented with the tragal pointer, accuracy in identifying the facial nerve trunk is very high, thereby avoiding inadvertent injury to the nerve trunk. PMID:24605304

  20. PubMed Central

    Mahieu, R.; Russo, S.; Gualtieri, T.; Colletti, G.

    2016-01-01

    SUMMARY The purpose of this report is to highlight how an unusual, outdated, unpopular and overlooked reconstructive method such as the masseter flap can be a reliable, straightforward and effective solution for oral reconstruction in selected cases. We report the transposition of the masseter crossover flap in two previously pre-treated patients presenting a second primary oral squamous cell carcinoma; excellent functional results with satisfactory cosmetic appearance were obtained in both cases. In the literature, only 60 cases of oral cavity and oropharyngeal reconstructions using the masseter flap have been reported. The possible clinical utility of this flap, even in modern head and neck reconstructive surgery, is presented and discussed. We believe that the masseter flap should enter in the armamentarium of every head and neck surgeon and be kept in mind as a possible solution since it provides an elegant and extremely simple procedure in suboptimal cases for microvascular reconstruction. PMID:27196079

  1. Anomalous course of the external carotid artery.

    PubMed

    Kawai, Katsushi

    2016-09-01

    The course and the branching patterns of the external carotid artery were investigated macroscopically in a total of 550 bodies or 1100 head sides of Japanese subjects, donated for student dissection at Kumamoto University from 1994 to 2014. With the exception of 14 head sides, the external carotid arteries running between the posterior belly of the digastric and stylohyoid muscles were found in 42 (3.87 %) out of 1086 head sides. Strictly speaking, they passed between the stylohyoid muscle and the stylohyoid branch of the facial nerve in 23 out of these 42 head sides. In the remaining 19 instances, the stylohyoid branch of the facial nerve was cut and its relationship to the external carotid artery was not clear. The external carotid artery running lateral to the intact stylohyoid branch of the facial nerve, medial to the digastric muscle was not found. The external carotid arteries running lateral to the digastric muscle were found in 4 (0.37 %) out of 1086 head sides. As a result, it is proposed that plural, potential courses of the external carotid artery originally exist and that some parts of such potential courses remain as branches of the external carotid artery in the usual instance, while the anomalous courses of the external carotid artery are induced mainly by anastomosis between the muscular branches supplying the wall of the head and neck in contrast to the usual external carotid artery induced mainly by the branches originally supplying the pharynx. PMID:26439732

  2. Neck hairline incision for simultaneous harvesting of temporal and mastoid fasciae: a technical note.

    PubMed

    Nazari, Shahriar; Bohluli, Behnam; Besharatizadeh, Rozina; Sadr-Eshkevari, Pooyan; Rashad, Ashkan

    2013-09-01

    Fasciae are known reservoirs of ideal graft material. The temporalis and mastoid fasciae are 2 of the most important graft reservoirs used by plastic surgeons, otolaryngologists, and oral and maxillofacial surgeons. The temporalis fascia is harvested predominantly by plastic surgeons, whereas otolaryngologists often prefer the mastoid fascia. In either case, graft harvesting might be accompanied by donor-site complications, such as hair loss, bleeding, hematoma, and scar formation, which can limit its application. To gain access to the temporal and mastoid fasciae simultaneously, the authors combined conventional techniques to develop a modified single-approach incision line that would minimize most donor-site complications. PMID:23706275

  3. Botulinum toxin in masticatory muscles: Short- and long-term effects on muscle, bone, and craniofacial function in adult rabbits

    PubMed Central

    Rafferty, Katherine L.; Liu, Zi Jun; Ye, Wenmin; Navarrete, Alfonso L.; Nguyen, Thao Tuong; Salamati, Atriya; Herring, Susan W.

    2012-01-01

    Paralysis of the masticatory muscles using botulinum toxin (BTX) is a common treatment for cosmetic reduction of the masseters as well as for conditions involving muscle spasm and pain. The effects of this treatment on mastication have not been evaluated, and claims that the treatment unloads the jaw joint and mandible have not been validated. If BTX treatment does decrease mandibular loading, osteopenia might ensue as an adverse result. Rabbits received a single dose of BTX or saline into one randomly chosen masseter muscle and were followed for 4 or 12 weeks. Masticatory muscle activity was assessed weekly, and incisor bite force elicited by stimulation of each masseter was measured periodically. At the endpoint, strain gages were installed on the neck of the mandibular condyle and on the molar area of the mandible for in vivo bone strain recording during mastication and muscle stimulation. After termination, muscles were weighed and mandibular segments were scanned with micro CT. BTX paralysis of one masseter did not alter chewing side or rate, in part because of compensation by the medial pterygoid muscle. Masseter-induced bite force was dramatically decreased. Analysis of bone strain data suggested that at 4 weeks, the mandibular condyle of the BTX-injected side was underloaded, as were both sides of the molar area. Bone quantity and quality were severely decreased specifically at these underloaded locations, especially the injection-side condylar head. At 12 weeks, most functional parameters were near their pre-injection levels, but the injected masseter still exhibited atrophy and percent bone area was still low in the condylar head. In conclusion, although the performance of mastication was only minimally harmed by BTX paralysis of the masseter, the resulting underloading was sufficient to cause notable and persistent bone loss, particularly at the temporomandibular joint. PMID:22155510

  4. Use of autologous grafts in the treatment of acquired penile curvature: An experience of 33 cases

    PubMed Central

    Khawaja, Abdul Rouf; Dar, Tanveer Iqbal; Zahur, Suhael; Tariq, Sheikh; Hamid, Arf; Wani, M. S.; Wazir, B. S.; Iqbal, Arsheed

    2016-01-01

    Aim: The objective was to compare the use of autologous dermal and temporalis fascia grafts in the treatment of acquired penile curvatures. Materials and Methods: It was a prospective observational study of 33 cases, conducted in Sher-i-Kashmir Institute of Medical Sciences, Srinagar from March 2007 to September 2013. All the patients had stable Peyronies disease (PD). Dorsal, dorsolateral and vental curvatures with good preoperative erections were included. PD index with visual analog scales for curvature was used preoperatively. An informed written consent was taken from all the patients with main emphasis on erectile dysfunction. Results: After an average follow up of 2 years, complete straightening of penis was observed in all patients with satisfactory sexual intercourse in 30 patients (90%). Three patients (10%) required frequent use of type 5 phosphodiesterase inhibitors for adequate erections. Overall 91% of patients and partners were satisfied with the procedure and cosmetically donor site was better in temporalis fascia graft site. No rejection of any graft was noted and glans hypoesthesia was noticed in 4 patients (12%). None of the patients required penile prosthesis. Total operative time for harvesting and application of the graft was more in dermal grafts (>3 hrs) than for temporalis fascia graft (2 hrs). Conclusion: Tunical lengthening procedures by autologous free grafts represents a safe and reproducible technique. A good preoperative erectile function is required for tunical lengthening procedure. Temporalis fascia graft is thin, tough membrane and effective graft for PD with good cosmetic and functional results. PMID:27141196

  5. Modified T-Plate Interpositional Arthroplasty for Temporomandibular Joint Ankylosis: A New and Versatile Option

    PubMed Central

    Ahmad, Imran; Bariar, Lalit Mohan

    2015-01-01

    Background This study has been conducted with the aim of evaluating modified T-plate interpositional arthroplasty. Methods A prospective comparative study in patients admitted with temporomandibular joint ankylosis. Ankylotic temporomandibular joint arthroplasty included condylectomy gap arthroplasty in 7, temporalis muscle flap interpositional arthroplasty in 8, and modified T-plate interpositional arthroplasty in 13 cases. The patients were followed for three years. Collected data were tabulated and subjected to Fisher's exact test, chi-square test and probability estimation. Results A significant increase in interincisal distance of 32 mm was seen in 12 (92.31%) patients in the T-plate interposition group, in 2 (25%) cases of the temporalis muscle flap interposition group, and in 1 case (14.28%) of the condylectomy group at 12, 24, and 36 months. Re-ankylosis was observed in 1 case (9.69%) of the T-plate interposition group, while as it was observed in 4 (50%) cases in the temporalis muscle flap interposition group and 4 (57.14%) cases in the condylectomy group, and these differences were statistically significant. Conclusions Our clinical experience with the use of the T-plate over the past 5 years has been encouraging, and our physiotherapy technique is quite simple. Even illiterate parents can assess it easily. Hence, we recommend this easy technique that does not damage the temporalis muscle for the management of temporomandibular joint ankylosis. PMID:26618118

  6. Local Applications of Myostatin-siRNA with Atelocollagen Increase Skeletal Muscle Mass and Recovery of Muscle Function

    PubMed Central

    Kawakami, Emi; Kawai, Nobuhiko; Kinouchi, Nao; Mori, Hiroyo; Ohsawa, Yutaka; Ishimaru, Naozumi; Sunada, Yoshihide; Noji, Sumihare; Tanaka, Eiji

    2013-01-01

    Background Growing evidence suggests that small-interfering RNA (siRNA) can promote gene silencing in mammalian cells without induction of interferon synthesis or nonspecific gene suppression. Recently, a number of highly specific siRNAs targeted against disease-causing or disease-promoting genes have been developed. In this study, we evaluate the effectiveness of atelocollagen (ATCOL)-mediated application of siRNA targeting myostatin (Mst), a negative regulator of skeletal muscle growth, into skeletal muscles of muscular dystrophy model mice. Methods and Findings We injected a nanoparticle complex containing myostatin-siRNA and ATCOL (Mst-siRNA/ATCOL) into the masseter muscles of mutant caveolin-3 transgenic (mCAV-3Tg) mice, an animal model for muscular dystrophy. Scrambled (scr) -siRNA/ATCOL complex was injected into the contralateral muscles as a control. Two weeks after injection, the masseter muscles were dissected for histometric analyses. To investigate changes in masseter muscle activity by local administration of Mst-siRNA/ATCOL complex, mouse masseter electromyography (EMG) was measured throughout the experimental period via telemetry. After local application of the Mst-siRNA/ATCOL complex, masseter muscles were enlarged, while no significant change was observed on the contralateral side. Histological analysis showed that myofibrils of masseter muscles treated with the Mst-siRNA/ATCOL complex were significantly larger than those of the control side. Real-time PCR analysis revealed a significant downregulation of Mst expression in the treated masseters of mCAV-3Tg mice. In addition, expression of myogenic transcription factors was upregulated in the Mst-siRNA-treated masseter muscle, while expression of adipogenic transcription factors was significantly downregulated. EMG results indicate that masseter muscle activity in mCAV-3Tg mice was increased by local administration of the Mst-siRNA/ATCOL complex. Conclusion These data suggest local administration of

  7. Repeated tongue lift movement induces neuroplasticity in corticomotor control of tongue and jaw muscles in humans.

    PubMed

    Komoda, Yoshihiro; Iida, Takashi; Kothari, Mohit; Komiyama, Osamu; Baad-Hansen, Lene; Kawara, Misao; Sessle, Barry; Svensson, Peter

    2015-11-19

    This study investigated the effect of repeated tongue lift training (TLT) on the excitability of the corticomotor representation of the human tongue and jaw musculature. Sixteen participants performed three series of TLT for 41 min on each of 5 consecutive days. Each TLT series consisted of two pressure levels (5 kPa and 10 kPa). All participants underwent transcranial magnetic stimulation (TMS) and electromyographic (EMG) recordings of motor evoked potentials (MEPs) in four sessions: (1) before TLT on Day 1 (baseline), (2) after TLT on Day 1, (3) before TLT on Day 5, and (4) after TLT on Day 5. EMG recordings from the left and right tongue dorsum and masseter muscles were made at three pressure levels (5 kPa, 10 kPa, 100% tongue lift), and tongue, masseter, and first dorsal interosseous (FDI) MEPs were measured. There were no significant day-to-day differences in the tongue pressure during maximum voluntary contractions. The amplitudes and thresholds of tongue and masseter MEPs after TLT on Day 5 were respectively higher and lower than before TLT on Day 1 (P<0.005), and there was also a significant increase in tongue and masseter MEP areas; no significant changes occurred in MEP onset latencies. FDI MEP parameters (amplitude, threshold, area, latency) were not significantly different between the four sessions. Our findings suggest that repeated TLT can trigger neuroplasticity reflected in increased excitability of the corticomotor representation of not only the tongue muscles but also the masseter muscles. PMID:26399776

  8. A clinical diagnosis of diurnal (non-sleep) bruxism in denture wearers.

    PubMed

    Piquero, K; Sakurai, K

    2000-06-01

    The purpose of this study was to establish a clinical method for diagnosing diurnal bruxism in denture wearers by recording masseter and anterior temporal electromyograph (EMG) activity. Seven suspected bruxists and five normal patients who wore complete dentures and/or distal extension base removable partial dentures were selected for participation. EMG activity in both the masseter and the anterior temporal muscles was recorded bilaterally during silent reading (10 min), maximal voluntary clenching (MVC), tapping in centric occlusion, lateral movements, chewing and swallowing. No significant differences of EMG activity were found between the groups during tapping, lateral movement, chewing and swallowing (P> 0.05). However, during 10 min of silent reading, a significant difference was found between the groups when comparing masseter muscle activity (P < 0.05). A threshold of 10% of MVC of at least 3-s duration was used to define an individual bruxism event. When the muscle activity recorded during silent reading was further analysed using these criteria, the control group displayed no bruxing activity while the suspected bruxist group displayed a mean frequency of six bruxism events (range 2-10). It was concluded that: (a) masseter muscle activity recorded during 10 min of silent reading showed significant difference between the groups; (b) the criteria selected in this study for the detection of sleep bruxism can also be used to assess diurnal bruxism; and (c) it is possible to diagnose diurnal bruxism in denture wearers by measuring the masseter EMG activity during 10 min of silent reading. PMID:10888274

  9. Morphomic analysis as an aid for preoperative risk stratification in patients undergoing major head and neck cancer surgery

    PubMed Central

    Rinkinen, Jacob; Agarwal, Shailesh; Beauregard, Jeff; Aliu, Oluseyi; Benedict, Matthew; Buchman, Steven R.; Wang, Stewart C.; Levi, Benjamin

    2016-01-01

    Background Patients undergoing major head and neck cancer surgery (MHNCS) may develop significant postoperative complications. To minimize the risk of complications, clinicians often assess multiple measures of preoperative health in terms of medical comorbidities. One emerging method to decrease surgical complications is preoperative assessment of patient frailty measured by specific tissue characteristics. We hypothesize that morphomic characteristics of the temporalis region serve as predictive markers for the development of complications after MHNCS. Methods We performed a retrospective review of 69 patients with available computed tomography (CT) imaging who underwent MHNCS from 2006–2012. To measure temporalis region characteristics, we used morphomic analysis of available preoperative CT scans to map out the region. All available CT scans had been performed as part of the patient’s routine work-up and were not ordered for morphomic analysis. We describe the correlation among temporalis fat pad volume (TFPV), mean zygomatic arch thickness, and incidence of postoperative complications. Results We noted significant difference in the zygomatic bone thickness and TFPV between patients who had medical complications, surgical complications, or total major complications and those who did not. Furthermore, by use of binary logistic regression, our data suggest decreased TFPV and zygomatic arch thickness are stronger predictors of developing postoperative complications than previously studies preoperative characteristics. Conclusions We describe morphomic analysis of the temporalis region in patients undergoing MHNCS to identify patients at risk for complications. Regional anatomic morphology may serve as a marker to objectively determine a patient’s overall health. Use of the temporalis region is appropriate in patients undergoing MHNCS because of the availability of preoperative scans as part of routine work up for head and/or neck cancer. PMID:25456114

  10. Multiple Muscular Variations in the Neck, Upper Extremity, and Lower Extremity Biased toward the Left Side of a Single Cadaver

    PubMed Central

    2015-01-01

    Although numerous reports have found accessory or supernumerary muscles throughout the human body, multiple appearances of these variations biased toward one side of body are rare. We report a 76-yr-old male cadaver with an accessory head of the biceps brachii and palmaris profundus, and a muscular slip between the biceps femoris and semitendinosus on the left side in addition to a bilateral accessory belly of the digastric muscle. No remarkable nervous, vascular, or visceral variation accompanied these variations. An interruption of normal somitogenesis or myogenesis may be a cause of these variations. PMID:25829821

  11. Rabies RNA synthesis, detected with cDNA probes, as a marker for virus transport in the rat nervous system.

    PubMed

    Ermine, A; Ceccaldi, P E; Masson, G; Tsiang, H

    1993-02-01

    The kinetics of viral RNA synthesis in different parts of the rat brain, infected with fixed or street rabies virus strains, is correlated with their anatomical neuronal connections with the masseter muscles, using hybridization with rabies cDNA probes. Viral RNA synthesis is first detected in the brain-stem and in the pons where the direct anatomical projection of the masseter muscle nervous arborization into the sensory and motor nuclei is located, through the trigeminus nerve. Rabies RNA detection is delayed in the other regions of the rat brain depending on the time course of virus transport from the trigeminal nuclei through multiple nervous connections. PMID:7681151

  12. The temporal bones from Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Spain). A phylogenetic approach.

    PubMed

    Martínez, I; Arsuaga, J L

    1997-01-01

    Three well-preserved crania and 22 temporal bones were recovered from the Sima de los Huesos Middle Pleistocene site up to and including the 1994 field season. This is the largest sample of hominid temporal bones known from a single Middle Pleistocene site and it offers the chance to characterize the temporal bone morphology of an European Middle Pleistocene population and to study the phylogenetic relationships of the SH sample with other Upper and Middle Pleistocene hominids. We have carried out a cladistic analysis based on nine traits commonly used in phylogenetic analysis of Middle and Late Pleistocene hominids: shape of the temporal squama superior border, articular eminence morphology, contribution of the sphenoid bone to the median glenoid wall, postglenoid process projection, tympanic plate orientation, presence of the styloid process, mastoid process projection, digastric groove morphology and anterior mastoid tubercle. We have found two autapomorphies on the Home erectus temporal bone: strong reduction of the postglenoid process and absence of the styloid process. Modern humans, Neandertals and the Middle Pleistocene fossils from Europe and Africa constitute a clade characterized by a convex superior border of the temporal squama. The European Middle Pleistocene fossils from Sima de los Huesos, Petralona, Steinheim, Bilzingsleben and Castel di Guido share a Neandertal apomorphy: a relatively flat articular eminence. The fossils from Ehringsdorf, La Chaise Suardi and Biache-Saint-Vaast also display another Neandertal derived trait: an anteriorly obliterated digastric groove. Modern humans and the African Middle Pleistocene fossils share a synapomorphy: a sagittally orientated tympanic plate. PMID:9300344

  13. Spontaneous Cerebrospinal Fluid Leaks in Congenital and Acquired Temporal Bone Defects—A Long-Term Follow-Up

    PubMed Central

    Wiet, Richard J.; Micco, Alan G.; Zhao, Jin-cheng

    1994-01-01

    Twelve patients presenting with tegmen defects and requiring surgical repair were retrospectively reviewed from 1982 to 1993. One half of the patients presented with a cerebrospinal fluid leak at some time in the course of their illness. Nine cases were considered to be acquired, secondary to previous mastoid surgery or trauma. All 9 had encephalocoeles. Three spontaneous leaks were considered congenital; 2 of these patients had encephalocoeles. This report represents a long-term follow-up of these cases, with an average follow-up of 7,6 years. Computed tomography and magnetic resonance imaging technology, as well as contrast studies, have tremendously aided in diagnosis and planning of surgical repair. Nine repairs were done through a dual transmastoid and middle fossa approach, with the other 3 done via a transmastoid approach only. We favored temporalis muscle flaps and temporalis fascia over synthetic materials for defect repairs. The long-term results and complications are discussed. PMID:17170935

  14. Evaluation of Fermentation, Drying, and/or High Pressure Processing on Viability of Listeria monocytogenes, Escherichia coli O157:H7, Salmonella spp., and Trichinella spiralis in Raw Pork and Genoa Salami

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the present study, we evaluated the effect of fermentation/drying on viability of T. spiralis in Genoa salami. We also evaluated HPP for efficacy towards T. spiralis larvae in trichinae-infected pig masseter muscle as an alternate to curing for trichinae control. We also validated the integrated ...

  15. Evaluation of Efficacy of Ultrasonography in the Assessment of Transcutaneous Electrical Nerve Stimulation in Subjects with Myositis and Myofascial Pain

    PubMed Central

    Patil, Seema; Iyengar, Asha R; B V, Subash; Joshi, Revan Kumar

    2016-01-01

    Background The study aimed to determine if ultrasonography of masseter can be used to evaluate the outcome of transcutaneous electrical nerve stimulation (TENS) in subjects with temporomandibular disorders (TMDs) such as myositis and myofascial pain. Methods Fifteen TMD subjects with myofascial pain/myositis who satisfied the RDC/McNeil criteria were included in the study. All the subjects were administered TENS therapy for a period of 6 days (30 minutes per session). The mouth opening (in millimeters) and severity of pain (visual analogue scale score) and ultrasonographic thickness of the masseter (in millimeters) in the region of trigger/tender areas was assessed in all the subjects both prior and post TENS therapy. A comparison of the pre-treatment and post-treatment values of the VAS score, mouth opening and masseter thickness was done with the help of a t-test. Results There was a significant reduction in the thickness of masseter muscle (P = 0.028) and VAS scores (P < 0.001) post TENS therapy. There was also a significant improvement in the mouth opening (P = 0.011) post TENS therapy. Conclusions In the present study, ultrasonography was found to be an effective measuring tool in the assessment of TENS therapy in subjects with myositis and myofascial pain. PMID:26839665

  16. [EMG functional changes in masticatory muscles by elastopositioner use in patients with TMJ dysfunction].

    PubMed

    Arsenina, O I; Popova, N V; Komarova, A V; Popova, A V; Pogabalo, I V; Ivanova, Yu A

    2015-01-01

    The analysis of the results of EMG studies in patients with TMJ dysfunction was carried out before and after use of elastpositioner "Corrector". The study revealed significant functional disturbances of the masticatory muscles, which were corrected after applying elastpositioner: there was a trend to decreased activity of masseter and temporal muscles, especially in the stagе of rest. PMID:26271702

  17. Effects of neuromuscular electrical stimulation on masticatory muscles in elderly stroke patients

    PubMed Central

    Wang, Joong-San; Lee, Ju-Hwan; Kim, Nyeon-Jun

    2015-01-01

    [Purpose] This study aimed to examine the effects of neuromuscular electrical stimulation on masticatory muscle activation in elderly stroke patients. [Subjects and Methods] The subjects included 20 elderly patients diagnosed with stroke and 10 healthy elderly individuals. The neuromuscular electrical stimulation group received stimulation on the masseter muscle in the affected side for 30 min each day, 3 times per week for 8 weeks. In all the subjects, surface electromyography was used to measure activity of the masseter and temporal muscles in both sides under resting and clenching conditions. [Results] In the neuromuscular electrical stimulation group, after the intervention, an increase in the activity of all of the masticatory muscles was observed during clenching, with a significant increase in the activity of the masseter muscle in the affected side. Significant differences between the groups were not observed after the interventions. [Conclusion] The results of this study suggest that application of neuromuscular electrical stimulation effectively improves muscle activity in elderly stroke patients during clenching, and that this technique can be applied particularly for the improvement of the clenching activity of the masseter muscle in the affected side. PMID:26504289

  18. Utility of Electromyographic Biological Feedback in Chronic Stuttering: A Clinical Study with Follow-Up.

    ERIC Educational Resources Information Center

    Manschreck, Theo C.; And Others

    1980-01-01

    Eight chronic adult stutterers underwent an electromyographic (EMG) biological feedback training program to reduce masseter muscle tension in an effort to improve fluency. All subjects mastered the program within 10 30-minute sessions. Measures of muscle tension and fluency indicated improvements that were maintained three to six months later.…

  19. [The dynamic complex of the temporomandibular meniscus].

    PubMed

    Couly, G; Hureau, J; Vaillant, J M

    1975-12-01

    The existence of meniscocapsular insertions of the temporal, masseter and external pterygoid muscles complicates the scheme of capsulo-meniscal dynamics. Our findings do indeed agree with those of DUBECQ (Bordeaux); but we think that the insertions of the masseter and the temporal are not only fine tracts. In the embryon, the meniscus is the preglossal mekelian conjunctival blastema, which receives the 3 masticatory muscles on its anterior border. In the adult, menisco-capsulo-muscular relationships are not modified; inspite of considerable functional adaptation of the articulation to varied stimuli, the menisco-capsular apparatus seems to be triply controlled by 3 musculo-masticatory bands, owing to the anterior premeniscal tendinous lamina, in histological continuity with the meniscus and rich in corpuscles of deep sensitivity. The resultant of the tridirectional muscular traction of the masseter, external pterygoid and temporal is a force in the postero-anterior oblique direction, downwards and forwards, which allows the meniscus to stretch, as was shown by Pr Delaire, and thus to have a sub-temporal sliding pathway of 8 to 12 mm. The three muscle bundles external pterygoid, temporal and masseter constitute the dynamic complex of the meniscus. PMID:1063432

  20. Repair of Temporal Bone Encephalocele following Canal Wall Down Mastoidectomy

    PubMed Central

    Magras, Ioannis; Kouskouras, Konstantinos

    2014-01-01

    We report a rare case of a temporal bone encephalocele after a canal wall down mastoidectomy performed to treat chronic otitis media with cholesteatoma. The patient was treated successfully via an intracranial approach. An enhanced layer-by-layer repair of the encephalocele and skull base deficit was achieved from intradurally to extradurally, using temporalis fascia, nasal septum cartilage, and artificial dural graft. After a 22-month follow-up period the patient remains symptom free and no recurrence is noted. PMID:25328738

  1. Effects of experimental craniofacial pain on fine jaw motor control: a placebo-controlled double-blinded study.

    PubMed

    Kumar, Abhishek; Castrillon, Eduardo; Svensson, Krister G; Baad-Hansen, Lene; Trulsson, Mats; Svensson, Peter

    2015-06-01

    The aim of the experiment was to test the hypothesis that experimental pain in the masseter muscle or temporomandibular joint (TMJ) would perturb the oral fine motor control, reflected in bigger variability of bite force values and jaw muscle activity, during repeated splitting of food morsels. Twenty healthy volunteers participated in four sessions. An intervention was made by injection of either 0.2 ml of monosodium glutamate/isotonic saline (MSG/IS) (randomized) in either the masseter or TMJ (randomized). The participants were asked to hold and split a flat-faced placebo tablet with their anterior teeth, thirty times each at baseline, during intervention and post-intervention. Pain was measured using a 0-10 visual analog scale. The force applied by the teeth to "hold" and "split" the tablet along with the corresponding electromyographic (EMG) activity of the jaw muscles and subject-based reports on perception of pain was recorded. The data analysis included a three-way analysis of variance model. The peak pain intensity was significantly higher during the painful MSG injections in the TMJ (6.1 ± 0.4) than the injections in masseter muscle (5.5 ± 0.5) (P = 0.037). Variability of hold force was significantly smaller during the MSG injection than IS injection in the masseter (P = 0.024). However, there was no significant effect of intervention on the variability of split force during the masseter injections (P = 0.769) and variability of hold and split force during the TMJ injections (P = 0.481, P = 0.545). The variability of the EMG activity of the jaw muscles did not show significant effects of intervention. Subject-based reports revealed that pain did not interfere in the ability to hold the tablet in 57.9 and 78.9 %, and the ability to split the tablet in 78.9 and 68.4 %, of the participants, respectively, during painful masseter and TMJ injections. Hence, experimental pain in the masseter muscle or TMJ did not have any robust effect in terms of bigger

  2. Multi-step EMG Classification Algorithm for Human-Computer Interaction

    NASA Astrophysics Data System (ADS)

    Ren, Peng; Barreto, Armando; Adjouadi, Malek

    A three-electrode human-computer interaction system, based on digital processing of the Electromyogram (EMG) signal, is presented. This system can effectively help disabled individuals paralyzed from the neck down to interact with computers or communicate with people through computers using point-and-click graphic interfaces. The three electrodes are placed on the right frontalis, the left temporalis and the right temporalis muscles in the head, respectively. The signal processing algorithm used translates the EMG signals during five kinds of facial movements (left jaw clenching, right jaw clenching, eyebrows up, eyebrows down, simultaneous left & right jaw clenching) into five corresponding types of cursor movements (left, right, up, down and left-click), to provide basic mouse control. The classification strategy is based on three principles: the EMG energy of one channel is typically larger than the others during one specific muscle contraction; the spectral characteristics of the EMG signals produced by the frontalis and temporalis muscles during different movements are different; the EMG signals from adjacent channels typically have correlated energy profiles. The algorithm is evaluated on 20 pre-recorded EMG signal sets, using Matlab simulations. The results show that this method provides improvements and is more robust than other previous approaches.

  3. Effect of clenching with a mouthguard on head acceleration during heading of a soccer ball.

    PubMed

    Narimatsu, Keishiro; Takeda, Tomotaka; Nakajima, Kazunori; Konno, Michiyo; Ozawa, Takamitsu; Ishigami, Keiichi

    2015-01-01

    Concussions are acceleration-deceleration injuries that occur when biomechanical forces are transmitted to the cerebral tissues. By limiting acceleration of the head, enhanced cervical muscle activity derived from clenching with a mouthguard (MG) may reduce the incidence or severity of concussions following impact. The purpose of this study was to investigate the effect of voluntary clenching with a proper MG on acceleration of the head during "heading" of a soccer ball. Eleven male high school soccer players (mean age, 16.8 years) participated in the study. Each player was given a customized MG. An automated soccer machine was used to project the ball at the participants at a constant speed. The participants headed the ball under 3 different oral conditions: drill 1, heading freely performed without instruction and without the MG; drill 2, heading performed as the subject was instructed to clench the masseter muscles tightly while not wearing the MG; drill 3, heading performed as the subject was instructed to clench tightly while wearing the MG. Each participant repeated each drill 5 times. Linear acceleration of the head was measured with a 3-axis accelerometer. Activity of the masseter and sternocleidomastoid muscles was measured by wireless electromyography. Weak masseter and sternocleidomastoid muscle activity was observed during drill 1. After the soccer players had been instructed to clench their masseter muscles (drills 2 and 3), statistically significant decreases in head acceleration and increases in masseter and sternocleidomastoid muscle activity were observed (P < 0.05; paired t test). The effect was stronger when the players wore the MG. Dentists should encourage soccer players to habitually clench while wearing a proper mouthguard to strengthen cervical muscle resistance as a way to mitigate the damage caused by heading. PMID:26545274

  4. Expression of 5-HT3 receptors and TTX resistant sodium channels (NaV1.8) on muscle nerve fibers in pain-free humans and patients with chronic myofascial temporomandibular disorders

    PubMed Central

    2014-01-01

    Background Previous studies have shown that 5-HT3-antagonists reduce muscle pain, but there are no studies that have investigated the expression of 5-HT3-receptors in human muscles. Also, tetrodotoxin resistant voltage gated sodium-channels (NaV) are involved in peripheral sensitization and found in trigeminal ganglion neurons innervating the rat masseter muscle. This study aimed to investigate the frequency of nerve fibers that express 5-HT3A-receptors alone and in combination with NaV1.8 sodium-channels in human muscles and to compare it between healthy pain-free men and women, the pain-free masseter and tibialis anterior muscles, and patients with myofascial temporomandibular disorders (TMD) and pain-free controls. Methods Three microbiopsies were obtained from the most bulky part of the tibialis and masseter muscles of seven and six healthy men and seven and six age-matched healthy women, respectively, while traditional open biopsies were obtained from the most painful spot of the masseter of five female patients and from a similar region of the masseter muscle of five healthy, age-matched women. The biopsies were processed by routine immunohistochemical methods. The biopsy sections were incubated with monoclonal antibodies against the specific axonal marker PGP 9.5, and polyclonal antibodies against the 5-HT3A-receptors and NaV1.8 sodium-channels. Results A similar percentage of nerve fibers in the healthy masseter (85.2%) and tibialis (88.7%) muscles expressed 5-HT3A-receptors. The expression of NaV1.8 by 5-HT3A positive nerve fibers associated with connective tissue was significantly higher than nerve fibers associated with myocytes (P < .001). In the patients, significantly more fibers per section were found with an average of 3.8 ± 3 fibers per section in the masseter muscle compared to 2.7 ± 0.2 in the healthy controls (P = .024). Further, the frequency of nerve fibers that co-expressed NaV1.8 and 5-HT3A receptors was significantly

  5. Neck muscle atrophy and soft-tissue fibrosis after neck dissection and postoperative radiotherapy for oral cancer

    PubMed Central

    Kim, Jinu; Shin, Eun Seow; Kim, Jeong Eon; Yoon, Sang Pil

    2015-01-01

    Late complications of head and neck cancer survivors include neck muscle atrophy and soft-tissue fibrosis. We present an autopsy case of neck muscle atrophy and soft-tissue fibrosis (sternocleidomastoid, omohyoid, digastric, sternohyoid, sternothyroid, and platysma muscles) within the radiation field after modified radical neck dissection type I and postoperative radiotherapy for floor of mouth cancer. A 70-year-old man underwent primary tumor resection of the left floor of mouth, left marginal mandibulectomy, left modified radical neck dissection type I, and reconstruction with a radial forearm free flap. The patient received adjuvant radiotherapy. The dose to the primary tumor bed and involved neck nodes was 63 Gy in 35 fractions over 7 weeks. Areas of subclinical disease (left lower neck) received 50 Gy in 25 fractions over 5 weeks. Adjuvant chemotherapy was not administered. PMID:26756035

  6. [Conservative forehead facelift. Design and preliminary results].

    PubMed

    Gola, R

    1999-06-01

    The digastric occipitofrontalis muscle, as described in classical anatomy text books, does not exist. The epicranial aponeurosis or galea aponeurotica receives the occipitalis muscle on its deep surface and the frontalis muscle on its superficial surface. This revised anatomy of the concept of the frontal cutaneo-musculo-aponeurotic unit, combining skin, galea and frontalis muscle (frontal CMAU) is the basis for a new forehead facelift which corrects ageing of the forehead, essentially related to recession of the forehead and relaxation of the galea. The essential advantage of this new facelift is preservation of the frontalis muscle which plays a fundamental role not only in forehead expression, but also in support and elevation of the eyelids. The absence of any direct procedure on the frontalis muscle decreases the extent of skin resection and avoids or minimizes sensory or motor neurological complications. PMID:10427829

  7. Anatomic landmarks for localization of the spinal accessory nerve.

    PubMed

    Durazzo, Marcelo D; Furlan, Julio C; Teixeira, Gilberto V; Friguglietti, Celso U M; Kulcsar, Marco A V; Magalhães, Roberto P; Ferraz, Alberto R; Brandão, Lenine G

    2009-05-01

    This anatomical study examines the anatomic topography and landmarks for localization of the spinal accessory nerve (SAN) during surgical dissections in 40 fresh human cadavers (2 females and 38 males; ages from 22 to 89 years with a mean of 60 years). In the submandibular region, the SAN was found anteriorly to the transverse process of the atlas in 77.5% of the dissections. When the SAN crossed the posterior belly of the digastric muscle, the mean distance from the point of crossing to the tendon of the muscle was 1.75 +/- 0.54 cm. Distally, the SAN crossed between the two heads of the SCM muscle in 45% of the dissections and deep to the muscle in 55%. The SAN exited the posterior border of the sternocleidomastoid muscle in a point superior to the nerve point with a mean distance between these two anatomic parameters of 0.97 +/- 0.46 cm. The mean overall extracranial length of the SAN was 12.02 +/- 2.32 cm, whereas the mean length of the SAN in the posterior triangle was 5.27 +/- 1.52 cm. There were 2-10 lymph nodes in the SAN chain. In conclusion, the nerve point is one of the most reliable anatomic landmarks for localization of the SAN in surgical neck dissections. Although other anatomic parameters including the transverse process of the atlas and the digastric muscle can also be used to localize the SAN, the surgeon should be aware of the possibility of anatomic variations of those parameters. Similar to previous investigations, our results suggest that the number of lymph nodes of the SAN chain greatly varies. PMID:19373901

  8. Transcervical excision of intramasseteric cavernous hemangioma: A case report

    PubMed Central

    CHENG, YU-TING; LAI, CHIEN-CHUNG

    2016-01-01

    Intramuscular hemangiomas (IMHs) of the masseter muscle are extremely rare in the head and neck region and, thus, are often misdiagnosed as parotid tumors prior to surgery. Excisional resection remains the standard treatment for IMH. Since these tumors are located on the proximal side of the facial nerve, it is important to preserve the facial nerve during surgery. This study reports the case of a 57-year-old male who presented with a progressive tender swelling on the right side of the face, which had been present for >6 months. Computed tomography of the neck revealed a heterogeneous highly-vascularized mass located in the superficial layer of the masseter muscle. The patient subsequently underwent surgical resection via a collar incision, and pathological examination revealed a cavernous IMH. During the one-year follow-up period, the patient exhibited a good prognosis, and one-year magnetic resonance imaging revealed no local recurrence. PMID:26998058

  9. Schwannoma arising from intramasseteric region.

    PubMed

    He, Yue; Fu, Hong Hai; He, Jie; Zhu, Han Guang; Zhang, Zhi Yuan

    2010-11-01

    Schwannoma in the head and neck is usually arising in the parapharyngeal space, but intramasseteric schwannoma is very rare. We report a schwannoma arising from masseter muscle in a middle-aged woman, who presented with a history of a painless right cheek mass for 3 years. Computed tomography scan suggested that the mass was located within the masseter muscle. Fine-needle aspiration was performed and showed spindle neoplastic cells, which were suspected to be of mesenchymal tissue origin. The mass was completely resected under general anesthesia. It was a well-circumscribed and lobulated mass, 4 × 3 × 2 cm in size. Histological examination gave the diagnosis of schwannoma, which was also confirmed by immunohistochemical stainings for S-100 and vimentin. Neurologic sequelae and recurrence were not found at 2 years after surgery. PMID:21119484

  10. [Anesthetic Management of a Patient with Facioscapulohumeral Muscular Dystrophy: Importance of Monitoring Neuromuscular Function at Multiple Sites].

    PubMed

    Matsui, Shuhei; Tanaka, Satoshi; Kiyosawa, Kenkichi; Tanaka, Toshiyuki; Kawamata, Mikito

    2015-12-01

    A 39-year-old female with facioscapulohumeral muscular dystrophy (FSHD) was scheduled for thoracoscopic resection of an anterior mediastinal tumor. She had slowly progressive weakness and atrophy in the fascial and shoulder girdle muscles. General anesthesia was induced and maintained with propofol, remifentanil, and fentanyl combined with thoracic paravertebral block. Rocuronium-induced neuromuscular blockade was evaluated with acceleromyography at the corrugator supercilii, masseter, and adductor pollicis muscles. There was no reaction at the atrophic corrugator supercilii muscle in response to train-of-four (TOF) stimulation even before rocuronium administration. In contrast twitch responses at the masseter and adductor pollicis muscles to TOF stimulation could be evoked and the duration of action of rocuronium was found to be similar to that of the normal population. The perioperative course was uneventful. Neuromuscular monitoring sites should be carefully selected in FSHD patients because of possible inability to monitor neuromuscular function at the atrophic muscles. PMID:26790332

  11. Frowning and Jaw Clenching Muscle Activity Reflects the Perception of Effort During Incremental Workload Cycling

    PubMed Central

    Huang, Ding-Hau; Chou, Shih-Wei; Chen, Yi-Lang; Chiou, Wen-Ko

    2014-01-01

    The present study aimed to investigate whether facial electromyography (EMG) recordings reflect the perception of effort and primary active lower limb muscle activity during incremental workload cycling. The effects of exercise intensity on EMG activity of the corrugator supercilii (CS), masseter and vastus lateralis (VL) muscles, heart rate (HR) and the rating of perceived exertion (RPE) were investigated, and the correlations among these parameters were determined. Eighteen males and 15 females performed continuous incremental workload cycling exercise until exhaustion. CS, masseter and VL muscle activities were continuously recorded using EMG during exercise. HR was also continuously monitored during the test. During the final 30 s of each stage of cycle ergometer exercise, participants were asked to report their feeling of exertion on the adult OMNI-Cycle RPE. HR and EMG activity of the facial muscles and the primary active lower limb muscle were strongly correlated with RPE; they increased with power output. Furthermore, facial muscle activity increased significantly during high-intensity exercise. Masseter muscle activity was strongly and positively correlated with HR, RPE and VL activity. The present investigation supports the view that facial EMG activity reflects the perception of effort. The jaw clenching facial expression can be considered an important factor for improving the reporting of perceived effort during high-intensity exercise in males and females. Key points Frowning and jaw clenching muscle activity reflects the perception of effort during incremental workload cycling. EMG activity of the masseter muscle was strongly and positively correlated with RPE, HR and lower limb EMG activity during incremental workload cycling. The jaw clenching facial expression can be considered an important factor for estimating the intensity of effort. PMID:25435786

  12. Neglected conditions producing preauricular and referred pain.

    PubMed Central

    Friedman, M H; Agus, B; Weisberg, J

    1983-01-01

    Various theories regarding temporomandibular joint symptoms are reviewed. Two hundred and forty six patients suffering from head, neck, or facial pain, or masticatory dysfunction were studied. In 108 of these patients, the diagnosis of temporomandibular joint synovitis, lateral pterygoid muscle dysfunction, or tenomyositis of the masseter muscle was made. Examination procedures, diagnosis, frequency of occurrence, and initial treatment of these conditions are described. Images PMID:6663304

  13. [Experimental study of oral hyperactivity caused by mental stress, in particular by aggression].

    PubMed

    Heggendorn, H; Vogt, H P; Graber, G

    1979-11-01

    18 patients without stomatognathic symptoms were examined by three psychological tests (Foto-Hand test, Freiburg personal inventory, and Giessen Test). Aggression had had the strongest effect upon masticatory muscles. Various other effects were studied, like ECG, respiration, pulse, tremor, skin resistance, masseter, biceps and triceps. Because of the visible effect upon the stomatognathic system it is plausible that disease in this organic system is to be expected at an early stage. PMID:293912

  14. Sialolithiasis of an accessory parotid gland: an unusual case.

    PubMed

    Debnath, S C; Adhyapok, A K

    2015-09-01

    We report a rare case of sialolithiasis of an accessory parotid gland, which was located anteromedial to the masseter muscle and isolated from the main parotid gland. The calculus developed from this accessory gland, and the main gland was free of lithiasis and inflammation. To our knowledge, there is no reported case of 14 stones in an accessory parotid salivary gland. The calculus was removed through a standard incision without injury to the facial nerve or a salivary fistula. PMID:26048098

  15. Aesthetic use of BoNT: Options and outcomes.

    PubMed

    Gendler, Ellen; Nagler, Arielle

    2015-12-01

    There are a multitude of uses for BoNT in the aesthetic realm. Efficacy has been shown in softening glabellar creases, crows feet, forehead rhytides, and in correcting facial asymmetries, including mild eyelid ptosis. Facial shape can be altered through injections of BoNT into masseter, and smiles can be altered with BoNT. Clinical examples of the above will be shown, as well as adverse outcomes with inaccurate injection techniques. PMID:26368007

  16. Surgical Intervention for Masticatory Muscle Tendon-Aponeurosis Hyperplasia Based on the Diagnosis Using the Four-Dimensional Muscle Model

    PubMed Central

    Nakaoka, Kazutoshi; Hamada, Yoshiki; Nakatani, Hayaki; Shigeta, Yuko; Hirai, Shinya; Ikawa, Tomoko; Mishima, Akira; Ogawa, Takumi

    2015-01-01

    Objectives: The surgical target of Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is the masseter or temporal muscle. In our clinic, the 4-dimentional muscle model (4DMM) has been used to decide if we should approach to the masseter or temporal muscle. The aim of this study is validate the clinical usefulness of 4DMM on the basis of the surgical results. Methods: The 4DMM was constructed from the digital data of 3D-CT and 4-dimentional mandibular movements of the patients. It made us to able to visually observe the expansion rate of masticatory muscles at maximum mouth opening comparing to their length at closed mouth position. Fifteen patients were applied the 4DMM before the surgical treatment and 2 healthy volunteers were enrolled as control group. Results: The expansion rate of temporal muscle at the maximum mouth opening in the patient group was significantly less than that in the control group (P < 0.05). On the other hand, the masseter muscles of all patients were expanded as same as the control group. Therefore the main cause of limitation of mouth-opening was suggested to be a contracture of the temporal muscle. Consequently, we performed successful bilateral coronoidectomy with no surgical intervention to the masseter muscles in all patients. Conclusion: The present 4DMM would be valuable modality to decide the target muscle of surgical treatment for patients with MMTAH. In this pathology, contracture of the temporal muscle seems to be main cause of limited mouth opening. PMID:26352365

  17. A relationship between bruxism and orofacial-dystonia? A trigeminal electrophysiological approach in a case report of pineal cavernoma

    PubMed Central

    2013-01-01

    Background In some clinical cases, bruxism may be correlated to central nervous system hyperexcitability, suggesting that bruxism may represent a subclinical form of dystonia. To examine this hypothesis, we performed an electrophysiological evaluation of the excitability of the trigeminal nervous system in a patient affected by pineal cavernoma with pain symptoms in the orofacial region and pronounced bruxism. Methods Electrophysiological studies included bilateral electrical transcranial stimulation of the trigeminal roots, analysis of the jaw jerk reflex, recovery cycle of masseter inhibitory reflex, and a magnetic resonance imaging study of the brain. Results The neuromuscular responses of the left- and right-side bilateral trigeminal motor potentials showed a high degree of symmetry in latency (1.92 ms and 1.96 ms, respectively) and amplitude (11 mV and 11.4 mV, respectively), whereas the jaw jerk reflex amplitude of the right and left masseters was 5.1 mV and 8.9 mV, respectively. The test stimulus for the recovery cycle of masseter inhibitory reflex evoked both silent periods at an interstimulus interval of 150 ms. The duration of the second silent period evoked by the test stimulus was 61 ms and 54 ms on the right and left masseters, respectively, which was greater than that evoked by the conditioning stimulus (39 ms and 35 ms, respectively). Conclusions We found evidence of activation and peripheral sensitization of the nociceptive fibers, the primary and secondary nociceptive neurons in the central nervous system, and the endogenous pain control systems (including both the inhibitory and facilitatory processes), in the tested subject. These data suggest that bruxism and central orofacial pain can coexist, but are two independent symptoms, which may explain why numerous experimental and clinical studies fail to reach unequivocal conclusions. PMID:24165294

  18. PubMed Central

    LABBÈ, D.; BUSSU, F.; IODICE, A.

    2012-01-01

    SUMMARY Long-standing peripheral monolateral facial paralysis in the adult has challenged otolaryngologists, neurologists and plastic surgeons for centuries. Notwithstanding, the ultimate goal of normality of the paralyzed hemi-face with symmetry at rest, and the achievement of a spontaneous symmetrical smile with corneal protection, has not been fully reached. At the beginning of the 20th century, the main options were neural reconstructions including accessory to facial nerve transfer and hypoglossal to facial nerve crossover. In the first half of the 20th century, various techniques for static correction with autologous temporalis muscle and fascia grafts were proposed as the techniques of Gillies (1934) and McLaughlin (1949). Cross-facial nerve grafts have been performed since the beginning of the 1970s often with the attempt to transplant free-muscle to restore active movements. However, these transplants were non-vascularized, and further evaluations revealed central fibrosis and minimal return of function. A major step was taken in the second half of the 1970s, with the introduction of microneurovascular muscle transfer in facial reanimation, which, often combined in two steps with a cross-facial nerve graft, has become the most popular option for the comprehensive treatment of long-standing facial paralysis. In the second half of the 1990s in France, a regional muscle transfer technique with the definite advantages of being one-step, technically easier and relatively fast, namely lengthening temporalis myoplasty, acquired popularity and consensus among surgeons treating facial paralysis. A total of 111 patients with facial paralysis were treated in Caen between 1997 and 2005 by a single surgeon who developed 2 variants of the technique (V1, V2), each with its advantages and disadvantages, but both based on the same anatomo-functional background and aim, which is transfer of the temporalis muscle tendon on the coronoid process to the lips. For a

  19. Effect of surgically assisted rapid maxillary expansion on masticatory muscle activity: A pilot study

    PubMed Central

    Sverzut, Cássio E.; Martorelli, Karinna; Jabur, Roberto; Petri, Alice D.; Trivellato, Alexandre E.; Siéssere, Selma; Regalo, Simone C. H.

    2011-01-01

    Background: The aim of the present study was to analyze the electromyographic (EMG) activity of masseter and temporal muscles of adult patients submitted to surgically assisted rapid maxillary expansion (SARME) before and after the surgery. Materials and Methods: The sample consisted of 19 adults, with ages ranging from 20 to 47 years (mean 25.4 years), with bilateral posterior cross bite requiring SARME treatment. The electromyographic activity of masseter and temporal muscles was analyzed before treatment (T1) and after the surgical procedure (T2). The mean interval between the two electromyographic analyses was 15 days. Results: The muscular active was electromyographically analyzed during the clinical situation of habitual gum chewing (10 sec), dental clenching (4 sec), mouth opening and closing (10 sec), rest (10 sec), protrusion (10 sec), and right and left laterality (10 sec). The measured differences between T1 and T2 data were evaluated using the paired t-test (SPSS 17.0 for Windows). The electromyographic analysis showed that the activity of the masseter and temporal muscles decreased significantly after the SARME in all the clinical situations after the surgery. Conclusion: According to the results of the present study, individuals after SARME surgery presented patterns of electromyographic contraction similar to those developed by dentate individuals during the movements of mandibular excursion. PMID:23482404

  20. Eating tools in hand activate the brain systems for eating action: a transcranial magnetic stimulation study.

    PubMed

    Yamaguchi, Kaori; Nakamura, Kimihiro; Oga, Tatsuhide; Nakajima, Yasoichi

    2014-07-01

    There is increasing neuroimaging evidence suggesting that visually presented tools automatically activate the human sensorimotor system coding learned motor actions relevant to the visual stimuli. Such crossmodal activation may reflect a general functional property of the human motor memory and thus can be operating in other, non-limb effector organs, such as the orofacial system involved in eating. In the present study, we predicted that somatosensory signals produced by eating tools in hand covertly activate the neuromuscular systems involved in eating action. In Experiments 1 and 2, we measured motor evoked response (MEP) of the masseter muscle in normal humans to examine the possible impact of tools in hand (chopsticks and scissors) on the neuromuscular systems during the observation of food stimuli. We found that eating tools (chopsticks) enhanced the masseter MEPs more greatly than other tools (scissors) during the visual recognition of food, although this covert change in motor excitability was not detectable at the behavioral level. In Experiment 3, we further observed that chopsticks overall increased MEPs more greatly than scissors and this tool-driven increase of MEPs was greater when participants viewed food stimuli than when they viewed non-food stimuli. A joint analysis of the three experiments confirmed a significant impact of eating tools on the masseter MEPs during food recognition. Taken together, these results suggest that eating tools in hand exert a category-specific impact on the neuromuscular system for eating. PMID:24835403

  1. Changes in masticatory muscle activity according to food size in experimental human mastication.

    PubMed

    Miyawaki, S; Ohkochi, N; Kawakami, T; Sugimura, M

    2001-08-01

    The purpose of this study was to investigate the changes in masticatory muscle activity according to food size in human mastication. Sixteen subjects performed deliberate unilateral chewing of similarly cone shaped hard gummy jellies weighing 5 and 10 g. The masseter and anterior temporal muscle activity on both sides was recorded for the first 10 strokes. The normalized muscle activity during the chewing of the 10 g jelly was significantly higher than that of the 5-g jelly, and there was a considerably high significant correlationship between the muscle activity during the chewing of the 10- and 5-g jellies in each muscle on each side. The 10 g/5 g jelly ratio for the masseter muscle activity on the non-chewing side almost coincided with the theoretical energy ratio required to shear, although that of the chewing side was lower than the ratio. The 10 g/5 g jelly ratio for the temporal muscle activity on both sides almost coincided with the food height ratio. The results suggest that anterior temporal and masseter muscle activity changes according to the rate of change in the height of hard coherent food bolus and food resistance required to shear, respectively, during mastication. PMID:11556960

  2. PubMed Central

    Nozaki, S.; Kawai, M.; Shimoyama, R.; Futamura, N.; Matsumura, T.; Adachi, K.; Kikuchi, Y.

    2010-01-01

    The purpose of this study is to evaluate whether the range of motion exercise of the temporo-mandibular joint (jaw ROM exercise) with a hot pack and massage of the masseter muscle improve biting disorder in Duchenne muscular dystrophy (DMD). The subjects were 18 DMD patients (21.3 ± 4.1 years old). The jaw ROM exercise consisted of therapist-assisted training (2 times a week) and self-training (before each meal every day). The therapist-assisted training consisted of the application of a hot pack on the cheek of the masseter muscle region (15 minutes), the massage of the masseter (10 minutes), and jaw ROM exercise (5 minutes). The self-training involved jaw ROM exercise by opening the mouth to the maximum degree, ten times. These trainings continued for six months. Outcomes were evaluated by measuring the greatest occlusal force and the distance at the maximum degree of mouth opening between an incisor of the top and that of the bottom. Six months later, the greatest occlusal force had increased significantly compared with that at the start of jaw ROM exercise (intermediate values: from 73.8N to 97.3N) (p = 0.005) as determined by the Friedman test and Scheffé's nonparametric test. The patients' satisfaction with meals increased. However, the maximum degree of mouth opening did not change after six months of jaw ROM exercise. Jaw ROM exercise in DMD is effective for increasing the greatest occlusal force. PMID:21574523

  3. Functional and anatomical basis for brain plasticity in facial palsy rehabilitation using the masseteric nerve.

    PubMed

    Buendia, Javier; Loayza, Francis R; Luis, Elkin O; Celorrio, Marta; Pastor, Maria A; Hontanilla, Bernardo

    2016-03-01

    Several techniques have been described for smile restoration after facial nerve paralysis. When a nerve other than the contralateral facial nerve is used to restore the smile, some controversy appears because of the nonphysiological mechanism of smile recovering. Different authors have reported natural results with the masseter nerve. The physiological pathways which determine whether this is achieved continue to remain unclear. Using functional magnetic resonance imaging, brain activation pattern measuring blood-oxygen-level-dependent (BOLD) signal during smiling and jaw clenching was recorded in a group of 24 healthy subjects (11 females). Effective connectivity of premotor regions was also compared in both tasks. The brain activation pattern was similar for smile and jaw-clenching tasks. Smile activations showed topographic overlap though more extended for smile than clenching. Gender comparisons during facial movements, according to kinematics and BOLD signal, did not reveal significant differences. Effective connectivity results of psychophysiological interaction (PPI) from the same seeds located in bilateral facial premotor regions showed significant task and gender differences (p < 0.001). The hypothesis of brain plasticity between the facial nerve and masseter nerve areas is supported by the broad cortical overlap in the representation of facial and masseter muscles. PMID:26683008

  4. Dark/light transition and vigilance states modulate jaw-closing muscle activity level in mice.

    PubMed

    Katayama, Keisuke; Mochizuki, Ayako; Kato, Takafumi; Ikeda, Minako; Ikawa, Yasuha; Nakamura, Shiro; Nakayama, Kiyomi; Wakabayashi, Noriyuki; Baba, Kazuyoshi; Inoue, Tomio

    2015-12-01

    Bruxism is associated with an increase in the activity of the jaw-closing muscles during sleep and wakefulness. However, the changes in jaw-closing muscle activity across states of vigilance over a 24-h period are unclear. In this study, we investigated the effects of dark/light transition and sleep/wake state on EMG activity of the masseter (jaw-closing) muscle in comparison with the activity of the upper trapezius muscle (a neck muscle) over a 24-h period in mice. The activities of the masseter and neck muscles during wakefulness were much greater than during non-REM and REM sleep. In contrast, the activities of both muscles slightly, but significantly, decreased during the transition period from dark to light. Histograms of masseter activity during wakefulness and non-REM sleep showed bimodal distributions, whereas the neck muscle showed unimodal activation in all states. These results suggest that the activities of jaw-closing and neck muscles are modulated by both sleep/wake state and dark/light transition, with the latter being to a lesser degree. Furthermore, even during non-REM sleep, jaw-closing muscles display bimodal activation, which may contribute to the occurrence of exaggerated aberrant muscle activity, such as sleep bruxism. PMID:26188127

  5. Use of Theraflex-TMJ topical cream for the treatment of temporomandibular joint and muscle pain.

    PubMed

    Lobo, Silvia Lobo; Mehta, Noshir; Forgione, Albert G; Melis, Marcello; Al-Badawi, Emad; Ceneviz, Caroline; Zawawi, Khalid H

    2004-04-01

    This randomized, double-blind study was designed to evaluate the effectiveness of the topical cream Theraflex-TMJ (NaBob/Rx, San Mateo, CA) in patients with masseter muscle pain and temporomandibular joint (TMJ) pain. Fifty-two subjects (5 males and 47 females) were instructed to apply a cream over the afflicted masseter muscle(s) or over the jaw joint(s) twice daily for two weeks. Theraflex-TMJ cream was used by the experimental group, while a placebo cream was used by the control group. The means of pain ratings were calculated prior to the application of the cream (baseline), after ten days of tx (period 1), and 15 days of tx (period 2) days of treatment and five days after stopping the treatment (follow-up). There was a significant decrease in reported pain levels from baseline in the experimental group for period 1 (p < 0.01), period 2 (p < 0.001), and follow-up (p < 0.01). For the control group, no significant differences were found between the different time periods (p > 0.05). There was evidence of minor side effects such as skin irritation and/or burning on the site of the application in two subjects in the experimental as well as two subjects in the control groups. The data strongly suggest that Theraflex-TMJ topical cream is safe and effective for reducing pain in the masseter muscle and the temporomandibular joint. PMID:15134414

  6. Change of Distribution and Timing of Bite Force after Botulinum Toxin Type A Injection Evaluated by a Computerized Occlusion Analysis System

    PubMed Central

    Song, Ji Hee; Cho, Eunae S.; Kim, Seong Taek

    2014-01-01

    Purpose The aim of this study was to determine the force distribution and pattern of mastication after injection of botulinum toxin type A (BTX-A) into both masseter muscles. The hypothesis to be tested was that the difference between right and left balance of occlusal force diminishes over time following BTX-A injection. Materials and Methods Fifteen patients were submitted to BTX-A injection therapy for subjective masseter hypertrophy. A total of 25 U of BTX-A (50 U in total) was injected into two points located 1 cm apart at the center of the lower one-third of both masseter muscles. All patients were examined using the T-Scan occlusion analysis system before and 4, 8, 12, and 24 weeks after BTX-A injection. Results A significant change in force balance was found between the right and left sides over time and the difference between the two sides decreased with the time post-injection, reaching a minimum at 12 weeks. Comparison of the force balance between the anterior and posterior occlusions revealed no significant difference at any of the time points. The occlusion and disclusion times (right and left sides) did not differ significantly with time since BTX-A injection. Conclusion A decline in the difference in the clenching force between the left and right sides was found with increasing time up to 12 weeks following BTX-A injection. PMID:24954346

  7. Mastication Improvement After Partial Implant-supported Prosthesis Use

    PubMed Central

    Gonçalves, T.M.S.V.; Campos, C.H.; Gonçalves, G.M.; de Moraes, M.; Rodrigues Garcia, R.C.M.

    2013-01-01

    Partially edentulous patients may be rehabilitated by the placement of removable dental prostheses, implant-supported removable dental prostheses, or partial implant fixed dental prostheses. However, it is unclear the impact of each prosthesis type over the masticatory aspects, which represents the objective of this paired clinical trial. Twelve patients sequentially received and used each of these 3 prosthesis types for 2 months, after which maximum bite force was assessed by a strain sensor and food comminution index was determined with the sieving method. Masseter and temporal muscle thicknesses during rest and maximal clenching were also evaluated by ultrasonography. Each maxillary arch received a new complete denture that was used throughout the study. Data were analyzed by analysis of variance for repeated measures, followed by the Tukey test (p < .05). Maximum bite force and food comminution index increased (p < .0001) after implant-supported dental prosthesis and implant fixed dental prosthesis use, with the higher improvement found after the latter’s use. Regardless of implant-retained prosthesis type, masseter muscle thickness during maximal clenching also increased (p < .05) after implant insertion. Partial implant-supported prostheses significantly improved masseter muscle thickness and mastication, and the magnitude of this effect was related to prosthesis type (International Clinical Trial Registration RBR-9J26XD). PMID:24158344

  8. Effectiveness of global postural reeducation in the treatment of temporomandibular disorder: case report.

    PubMed

    Monteiro, Wagner; Francisco de Oliveira Dantas da Gama, Thomaz; dos Santos, Robiana Maria; Collange Grecco, Luanda André; Pasini Neto, Hugo; Oliveira, Claudia Santos

    2013-01-01

    The aim of the present study was to evaluate the effectiveness of global postural reeducation in the treatment of temporomandibular disorder through bilateral surface electromyographic (EMG) analysis of the masseter muscle in a 23-year-old volunteer. EMG values for the masseter were collected at rest (baseline) and during a maximal occlusion. There was a change in EMG activity both at rest and during maximal occlusion following the intervention, evidencing neuromuscular rebalancing between both sides after treatment as well as an increase in EMG activity during maximal occlusion, with direct improvement in the recruitment of motor units during contractile activity and a decrease in muscle tension between sides at rest. The improvement in postural patterns of the cervical spine provided an improvement in aspects of the EMG signal of the masseter muscle in this patient. However, a multidisciplinary study is needed in order to determine the effect of different forms of treatment on this condition and compare benefits between interventions. Therefore, this study can provide a direction regarding the application of this technique in patients with temporomandibular disorder. PMID:23294684

  9. Deformation of Nasal Septal Cartilage During Mastication

    PubMed Central

    Dayeh, Ayman A. Al; Rafferty, Katherine L.; Egbert, Mark; Herring, Susan W.

    2009-01-01

    The cartilaginous nasal septum plays a major role in structural integrity and growth of the face, but its internal location has made physiologic study difficult. By surgically implanting transducers in 10 miniature pigs (Sus scrofa), we recorded in vivo strains generated in the nasal septum during mastication and masseter stimulation. The goals were (1) to determine whether the cartilage should be considered as a vertical strut supporting the nasal cavity and preventing its collapse, or as a damper of stresses generated during mastication and (2) to shed light on the overall pattern of snout deformation during mastication. Strains were recorded simultaneously at the septo-ethmoid junction and nasofrontal suture during mastication. A third location in the anterior part of the cartilage was added during masseter stimulation and manipulation. Contraction of jaw closing muscles during mastication was accompanied by anteroposterior compressive strains (around −1,000 με) in the septo-ethmoid junction. Both the orientation and the magnitude of the strain suggest that the septum does not act as a vertical strut but may act in absorbing loads generated during mastication. The results from masseter stimulation and manipulation further suggest that the masticatory strain pattern arises from a combination of dorsal bending and/or shearing and anteroposterior compression of the snout. J. Morphol. PMID:19434723

  10. Effects of temperature on blood flow in facial tissues

    SciTech Connect

    Kwon, H.J.; Rhee, J.G.; Song, C.W.; Waite, D.E.

    1986-10-01

    This study evaluated the effect of temperature on blood flow by using rubidium 86 to determine the fraction of cardiac output going to specific facial tissues of rats. Seventy-seven male Holtzman rats were divided into two groups and various subgroups. The intraoral subgroups were categorized according to the temperature of the water irrigating the oral cavity (11, 39, 41, 43, or 45/sup 0/C). The extraoral subgroups were categorized according to whether heat or ice was applied to the cheek of the rats and the duration of application (10 or 20 minutes). Rats were killed within 60 seconds after injection of 86Rb, and tissue samples were taken from the buccal mucosa, facial skin, masseter muscle, mandible, tongue, and maxilla. The fraction of isotope uptake in each gram of these tissues (FU/g) was then calculated. For the intraoral group, the bath temperature of 39/sup 0/C increased the FU/g in all tissues except masseter muscle and tongue. Higher bath temperature did not further alter the FU/g. Lowering the temperature to 11 degrees C changed the FU/g significantly only in the tongue. For the extraoral group, 20-minute application of ice was required to reduce FU/g significantly in all tissues but masseter muscle and skin. Extraoral heat application for 10 minutes increased FU/g significantly in skin and tongue, but no further change was seen after 20 minutes of application.