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Sample records for masseter temporalis digastric

  1. A comparative study of electromyograms of the masseter, temporalis, and anterior digastric muscles obtained by surface and intramuscular electrodes: raw-EMG.

    PubMed

    Koole, P; de Jongh, H J; Boering, G

    1991-07-01

    Electromyographic activity was synchronously recorded by surface and intramuscular electrodes in the same muscle. The activity of the left masseter, left temporalis, and both bellies of the anterior digastric muscle was studied by this double registration technique. In rest position no electromyographic activity could be detected in any of the muscles by both techniques. Both techniques give comparable results in cyclic jaw movements. In isometric contractions, however, differences in the registered activity were observed between the surface electrode on the depressor group muscles and the intramuscularly recorded anterior digastric muscles. Silent periods evoked in the elevator muscles were of slightly longer duration when recorded by intramuscular electrodes than when recorded by surface electrodes. A protruded position of the mandible results in a silent period of longer duration than the position of the mandible in maximal occlusion during clenching for both techniques.

  2. Heterogeneity of fiber characteristics in the rat masseter and digastric muscles.

    PubMed

    Sano, R; Tanaka, E; Korfage, J A M; Langenbach, G E J; Kawai, Nobuhiko; van Eijden, T M G J; Tanne, K

    2007-10-01

    The functional requirements in muscle use are related to the fiber type composition of the muscles and the cross-sectional area of the individual fibers. We investigated the heterogeneity in the fiber type composition and fiber cross-sectional area in two muscles with an opposing function, namely the digastric and masseter muscles (n = 5 for each muscle) of adult male rats, by means of immunohistochemical staining according to their myosin heavy chain (MyHC) content. The digastric and masseter muscles were taken from Wistar strain male rats 10 weeks old. In the masseter six predefined sample locations were examined; in the digastric four. Most regions showed dominant proportions of type IIA and IIX fibers. However, both muscles also revealed a regional heterogeneity in their fiber type distribution. In the digastric, type I fibers were detected only at the central and deep areas of the anterior and posterior belly, respectively. Meanwhile, the peripheral area of the anterior belly contained a higher proportion of type IIB fibers. In the masseter, the type I fibers were absent. In the superficial masseter the distribution of IIA and IIB fibers was significantly different between the superior and inferior regions. In the deep masseter, regional differences were observed among all four examined areas, of which the posterolateral region contained the highest proportion of type IIB fibers. The cross-sectional areas of type IIB fibers were always the largest, followed by the type IIX and IIA fibers. Only a few differences in cross-sectional area of corresponding fiber types were detected between the various sites. In conclusion, the masseter and digastric muscles showed an obvious heterogeneity of fiber type composition and fiber cross-sectional area. Their heterogeneity reflects the complex role of the both muscles during function. This detailed description of the fiber type composition can serve as a reference for future studies examining the muscular adaptations after

  3. H-reflexes in masseter and temporalis muscles in man.

    PubMed

    Macaluso, G M; De Laat, A

    1995-01-01

    In contrast with limb muscles, studies on H-reflexes in the trigeminal system are scarce. The present report aimed at reevaluating the responses obtained in the masseter and temporalis muscles after electrical stimulation of their nerves. Twenty-four subjects participated in the experiments. The reflexes were elicited in the masseter and temporal muscles by monopolar stimulation and recorded using surface electrodes. Stimulation of the masseteric nerve evoked an M-response in the masseter and an H-reflex in both the masseter and the temporal muscles. In contrast with the masseter muscle, where the homonymous H-reflex disappeared at higher stimulation intensities, the heteronymous temporal H-reflex remained and reached a plateau. Simultaneous stimulation of the masseteric and deep temporal nerves resulted in an M-response and an H-reflex in both the masseter and temporal muscles. Increasing stimulus intensitites led to disappearance of the H-reflex in both muscles. The results were compared with those obtained by others on limb muscles. As in these muscles, the presence of heteronymous H-reflexes in the jaw muscles can be used in future studies of motoneuronal excitability.

  4. Fatigue in the masseter and temporalis muscles at constant load.

    PubMed

    Sforza, Chiarella; Zanotti, Gianfranco; Mantovani, Enrica; Ferrario, Virgilio F

    2007-01-01

    Fatigue is usually defined as the point at which a particular level of force can be no longer maintained. In the present study, surface EMG of the masseter and temporalis anterior muscles was measured in ten healthy young adults performing a unilateral molar (right side) clench. The subjects clenched on a bite force transducer at a fixed force level of 13 kg (127 N) as long as they could (endurance). The test ended when the subjects could no longer produce the required bite force. From the EMG recordings, the median power frequency was calculated at the beginning of the task (T0), after one minute of clenching (T1), and at the end of the task (T2, endurance time). For each subject and muscle, percentage decrements in the median power frequency were also computed at T1 and T2. Endurance time ranged between 79 and 470 s. Significant modifications in the median power frequency in both masseter muscles (right side, p=0.003; left side, p=0.02, analysis of variance) were found, with a significant difference for the median frequency at T2 (p<0.02 at post hoc test). The modifications in the temporalis muscles were not significant (p>0.05). Additionally, at T1, significant percentage decrements in the median power frequency were found for both right side muscles (p<0.05, paired Student's ). The left side muscles modifications (p>0.05) were not significant. A significant effect of side was found (p=0.007, analysis of variance), without effects of muscle and no muscle x side interaction. At T2, both masseter muscles and the right side temporalis had a significant modification in their median power frequency. Overall, the modifications were larger in the masseter than in the temporalis muscles (p=0.022, analysis of variance), without effects of side and no muscle x side interaction. In conclusion, a fixed submaximal muscular contraction provoked fatigue modifications in the EMG power spectra that were well comparable to those obtained in previous investigations using forces

  5. Task-related electromyographic spectral changes in the human masseter and temporalis muscles.

    PubMed

    Farella, Mauro; Van Eijden, Theo; Baccini, Michela; Michelotti, Ambra

    2002-02-01

    The masticatory muscles differ in their fiber type composition. It can therefore be expected that their electromyographic (EMG) power spectra will differ during the performance of different bite force tasks. In the present study, surface EMG activity was picked up from the masseter and from the anterior and posterior temporalis muscles of nine adult subjects. At a bite force level as low as 25 N, the mean power frequency (MPF) values of the posterior temporalis were significantly lower than those of the masseter and anterior temporalis. The MPF values of the masseter muscles decreased with an increase of bite force magnitude, whereas the MPF values of the anterior and posterior temporalis did not change significantly. The MPF values were significantly influenced by the direction of bite force. The observed changes of MPF are possibly related to the recruitment of different fiber types, and support the concept that the masticatory muscles behave heterogeneously.

  6. Mechanism of motor coordination of masseter and temporalis muscles for increased masticatory efficiency in mice.

    PubMed

    Yoshimi, Tomoko; Koga, Yoshiyuki; Nakamura, Aya; Fujishita, Ayumi; Kohara, Haruka; Moriuchi, Emi; Yoshimi, Keiko; Tsai, Chi-Yang; Yoshida, Noriaki

    2017-02-09

    The demand for the use of mice as animal models for elucidating the pathophysiologies and pathogeneses of oral motor disorders has been increasing in recent years, as more and more kinds of genetically modified mice that express functional disorders of the stomatognathic system become available. However, the fundamental characteristics of mouse jaw movements during mastication have yet to be fully elucidated. The purpose of this study was to investigate the roles of the masseter and temporalis muscles, and the mechanisms of motor coordination of these muscles for increasing masticatory efficiency in the closing phase in mice. Twenty-two male Jcl:ICR mice were divided into control (n = 8), masseter hypofunction (n = 7), and temporalis hypofunction groups (n = 7). Botulinum neurotoxin type A (BoNT⁄A) was used to induce muscle hypofunction. The masticatory movement path in the horizontal direction during the occlusal phase became unstable after BoNT⁄A injection into the masseter muscle. BoNT⁄A injection into the temporalis muscle decreased antero-posterior excursion of the late-closing phase corresponding to the power phase of the chewing cycle. These results suggest that the masseter plays an important role in stabilizing the grinding path, where the food bolus is ground by sliding the posterior teeth from back to front during the occlusal phase. The temporalis plays a major role in retracting the mandible more posteriorly in the early phase of closing, extending the grinding path. Masticatory efficiency is thus increased based on the coordination of activities by the masseter and temporalis muscles. This article is protected by copyright. All rights reserved.

  7. Electromyographic analysis of fatigue in temporalis and masseter muscles during continuous chewing.

    PubMed

    Buzinelli, R V; Berzin, F

    2001-12-01

    The aim of this study was to evaluate the electromyographic changes in the anterior temporalis and masseter muscles after fatigue induced by continuous chewing. Surface electrodes were placed bilaterally over the anterior temporalis and masseter muscles of 31 subjects with normal dentition. Recordings were taken every minute from the beginning of chewing to the exact moment the volunteer reported subjective sensation of fatigue in the jaw muscles. The length of endurance period (fatigue threshold) was measured to each subject, as well as the average amplitude and duration of activation phase and duration of relaxation phase through electromyographic recording of each muscle. The average endurance period was about 500 s. No significant change occurred on the average amplitude of activation phase meanwhile the duration of both the activation and relaxation phase diminished after fatigue.

  8. The immediate effect of hard and soft splints on the EMG activity of the masseter and temporalis muscles.

    PubMed

    al-Quran, F A; Lyons, M F

    1999-07-01

    The aim of this study was to compare the effects of hard and soft splints on the activity of the anterior temporalis and masseter muscles. Surface EMG recordings were made from these muscles during clenching at 10% of maximum, 50% of maximum and at maximum clench, both before and after insertion of a hard splint. This sequence was then repeated with a soft splint. The relative level of activity in the anterior temporalis and masseter muscles at all three activity levels was quantified by means of an Activity Index, which provides a measure of the balance of activity in the masseter relative to the activity in the anterior temporalis muscle. It was found that hard splints led to a decrease in EMG activity in relation to activity with no splint in both muscles at maximum clench and particularly the anterior temporalis. Soft splints produced a slight increase in activity of both muscles, but particularly the masseter muscle. The Activity Index indicated a shift in the balance of activity away from the anterior temporalis muscles with both splints, particularly at 10% of the maximum clenching level. It is possible that the decrease in activity of the temporalis muscles relative to the masseter muscles may be a factor in the therapeutic effect of both a hard and a soft splint, although the decrease is clearly greater with the hard splint.

  9. 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. © 2015 Wiley Periodicals, Inc.

  10. Reproducibility of surface EMG in the human masseter and anterior temporalis muscle areas.

    PubMed

    Castroflorio, Tommaso; Icardi, Katia; Torsello, Ferruccio; Deregibus, Andrea; Debernardi, Cesare; Bracco, Pietro

    2005-04-01

    The aim of this study was to test the hypothesis that surface electromyography (sEMG) recordings, made at mandibular rest position from the masseter and temporalis anterior areas, are intra- and inter-session reproducible. A template was designed and built to permit the correct electrode placement from one session to the next session. A sample of 18 subjects was examined. Two groups, homogeneous for age, sex, and craniofacial morphology were selected. The first group included asymptomatic subjects with no signs or symptoms of temporomandibular joint dysfunction (TMD) and the second group included patients suffering from muscle-related TMD. Data were obtained from different sEMG recordings made at mandibular rest position in the same session and in different sessions, repositioning the electrodes using a template designed for that purpose. The electromyograph used in this, study is part of the EMG K6-I Win Diagnostic System. Results showed that reproducibility of sEMG signals from the masseter and anterior temporalis areas at mandibular rest position is possible.

  11. Electromyographic analysis of masseter and anterior temporalis muscle in sleep bruxers after occlusal splint wearing.

    PubMed

    Amorim, Cesar Ferreira; Vasconcelos Paes, Fernando José; de Faria Junior, Newton Santos; de Oliveira, Luis Vicente Franco; Politti, Fabiano

    2012-04-01

    Bruxism is widely defined as an anxiety response to environmental stress. Occlusal splints are frequently used in sleep bruxism, to protect teeth from damage resulting from the contraction force of mandibular muscles, or to reduce the orofacial pain by relaxing masticatory muscles. Surface electromyography (EMG) of the right and left masseter and temporalis muscles was performed in 15 women presenting sleep bruxism and temporomandibular disorders related to occupational stress, after nocturnal use of the occlusal splint. The EMG signals were recorded twice per patient: After a work shift (pre-splint) and after a night of sleep with the occlusal splint (post-splint) before a new workday. The parametric t-paired test was used to compare differences of the RMS amplitude between pre and post-splint records, for resting and maximal clenching effort. The level of significance for each comparison was set to p < 0.05. The results of the study supports the premise that the use of occlusal splint reduces EMG activity in the masseter and anterior temporalis muscles, in patients who presented with sleep bruxism related to occupational stress.

  12. In vitro quantification of strain patterns in the craniofacial skeleton due to masseter and temporalis activities.

    PubMed

    Maloul, Asmaa; Regev, Eran; Whyne, Cari M; Beek, Marteen; Fialkov, Jeffrey A

    2012-09-01

    Many complications in craniofacial surgery can be attributed to a lack of characterization of facial skeletal strain patterns. This study aimed to delineate human midfacial strain patterns under uniform muscle loading. The left sides of 5 fresh-frozen human cadaveric heads were dissected of all soft tissues except the temporalis and masseter muscles. Tensile forces were applied to the free mandibular ends of the muscles. Maxillary alveolar arches were used to restrain the skulls. Eight strain gauges were bonded to the surface of the midface to measure the strain under single muscle loading conditions (100 N). Maxillary strain gauges revealed a biaxial load state for both muscles. Thin antral bone experienced high maximum principal tensile strains (maximum of 685.5 με) and high minimum principal compressive strains (maximum of -722.44 με). Similar biaxial patterns of lower magnitude were measured on the zygoma (maximum of 208.59 με for maximum principal strains and -78.11 με for minimum principal strains). Results, consistent for all specimens and counter to previously accepted concepts of biomechanical behavior of the midface under masticatory muscle loading, included high strain in the thin maxillary antral wall, rotational bending through the maxilla and zygoma, and a previously underestimated contribution of the temporalis muscle. This experimental model produced repeatable strain patterns quantifying the mechanics of the facial skeleton. These new counterintuitive findings underscore the need for accurate characterization of craniofacial strain patterns to address problems in the current treatment methods and develop robust design criteria.

  13. Temporalis and masseter muscle activity in patients with anterior open bite and craniomandibular disorders.

    PubMed

    Bakke, M; Michler, L

    1991-06-01

    Activity in temporalis and masseter muscles, and traits of facial morphology and occlusal stability were studied in 22 patients (19 women, 3 men; 15-45 yr of age) with anterior open bite and symptoms and signs of craniomandibular disorders. Facial morphology was assessed by profile radiographs, occlusal stability by tooth contacts, and craniomandibular function by clinical and radiological examination. Electromyographic activity was recorded by surface electrodes after primary treatment with a reflex-releasing, stabilizing splint. Maximal voluntary contraction was reduced compared to reference values, particularly in subjects with muscular affection, but maximal activity increased significantly when biting on the splint. Maximal voluntary contraction was positively correlated to molar contact and negatively to anterior face height, mandibular inclination, vertical jaw relation and gonial angle. Relative loading of the muscles was markedly increased during resting posture. It was concluded that reduced occlusal stability and long-face morphology were associated with weak elevator muscle activity with disposition overload and tenderness. The results also indicated that increase of occlusal stability might lead to increased muscle strength and possibly reduce risk of physical strain.

  14. Longitudinal changes in muscle activity of masseter and anterior temporalis before and after Lefort I osteotomies, An EMG study.

    PubMed

    Priyadarsini, P; Muthushekar, M R

    2011-07-01

    The aim of this study was to compare the levels of electromyography (EMG) activity of masseter and anterior temporalis present presurgically with changes in the intensity of muscle activity that took place post surgically for a period of 6 months follow up. Ten patients with vertical maxillary excess were selected from the department of Oral and Maxillofacial surgery at Saveetha Dental College and Hospitals, Chennai. Electromyography was used as a kinesiology tool to study muscle function of Masseter and Anterior Temporalis of all ten subjects pre surgically and post surgically with a 6 month follow up. The statistical package SPSSPC+ (Statistical Package for Social Science, Version 4.0.1) was used for statistical analysis. Mean and standard deviation were estimated from the sample. The tests that were used for the statistical analysis were one way ANOVA and student's T test. The final inference elucidates that the muscular activity of masseter and temporalis are improved during chewing and clenching in the postoperative 6 months period when compared to preoperative values. The duration was constant at 7 milliseconds for both the positions. From this study, it can be concluded that there is a strong correlation between vertical maxillary excess and associated weak musculature. Electromyography has been used as an important tool to demonstrate improved muscle activity after surgical correction of vertical maxillary excess and improvement in functional deficits associated with this dentofacial deformity. From this study it can be concluded that surgical correction of vertical maxillary excess improves occlusion, leading to increased eccentric tooth contacts, increased mean amplitude and increased mean power frequency of the muscles all of which translate into improved muscle activity.

  15. Longitudinal changes in muscle activity of masseter and anterior temporalis before and after Lefort I osteotomies, An EMG study

    PubMed Central

    Priyadarsini, P.; Muthushekar, M. R.

    2011-01-01

    Aims: The aim of this study was to compare the levels of electromyography (EMG) activity of masseter and anterior temporalis present presurgically with changes in the intensity of muscle activity that took place post surgically for a period of 6 months follow up. Settings and Design: Ten patients with vertical maxillary excess were selected from the department of Oral and Maxillofacial surgery at Saveetha Dental College and Hospitals, Chennai. Materials and Methods: Electromyography was used as a kinesiology tool to study muscle function of Masseter and Anterior Temporalis of all ten subjects pre surgically and post surgically with a 6 month follow up. Statistical Analysis Used: The statistical package SPSSPC+ (Statistical Package for Social Science, Version 4.0.1) was used for statistical analysis. Mean and standard deviation were estimated from the sample. The tests that were used for the statistical analysis were one way ANOVA and student's T test. Results: The final inference elucidates that the muscular activity of masseter and temporalis are improved during chewing and clenching in the postoperative 6 months period when compared to preoperative values. The duration was constant at 7 milliseconds for both the positions. Conclusions: From this study, it can be concluded that there is a strong correlation between vertical maxillary excess and associated weak musculature. Electromyography has been used as an important tool to demonstrate improved muscle activity after surgical correction of vertical maxillary excess and improvement in functional deficits associated with this dentofacial deformity. From this study it can be concluded that surgical correction of vertical maxillary excess improves occlusion, leading to increased eccentric tooth contacts, increased mean amplitude and increased mean power frequency of the muscles all of which translate into improved muscle activity. PMID:23482429

  16. Fatigue analysis in the masseters and temporalis muscles in patients with temporomandibular disorder during short period of mastication.

    PubMed

    Caria, Paulo H F; Bigaton, Delaine R; de Oliveira, Anamaria S; Bérzin, Fausto

    2009-01-01

    The purpose of this experiment was to look for signals of muscle fatigue in volunteers with Temporomandibular Disorders (TMD) during short period of mastication. Twenty female volunteers selected by Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) participated, 10 with myogenic TMD (experimental) and 10 clinically normal (control). The Masseter and Temporalis muscles were evaluated electromyographically with active differential surface electrodes. The masticatory activity was recorded for 15 seconds and the signals were normalized by 4 seconds of teeth clenching. Three complete masticatory cycles were taken to calculating the median frequency (MF) and electromyographic amplitude (RMS). The data were submitted to statistics analysis and non-parametric tests. The results showed that RMS and median frequency did not change during the mastication period analyzed, indicating the absence of muscle fatigue, for the Masseter and Temporalis muscles in both groups (p> 0.05). These results confirm the absence of signals of muscle fatigue in masticatory muscles during short period of mastication even in individuals with TMD, possibly due to increased of blood flow, consequence of dynamic muscle contraction and the individual characteristics of muscle fiber composition and recruitment.

  17. Pressure pain thresholds assessed over temporalis, masseter, and frontalis muscles in healthy individuals, patients with tension-type headache, and those with migraine--a systematic review.

    PubMed

    Andersen, Sanne; Petersen, Marie Weinreich; Svendsen, Anette Sand; Gazerani, Parisa

    2015-08-01

    A systematic review was conducted to identify and summarize the available scientific literature addressing pressure pain threshold (PPT) values over the temporalis, masseter, and frontalis muscles in healthy humans, patients with tension-type headache (TTH), and those with migraine both in males and females. Six relevant medical databases for the literature search were included: PubMed, Web of Science, Cochrane, CINAHL, BioMed Central, and Embase. The search strategy was performed applying 15 keywords (eg, pressure pain threshold, temporalis muscle, tension type headache, pressure algometer) and their combinations. A total of 156 articles were identified, and 40 relevant articles were included. The main outcomes of the systematic review were extracted, and it was demonstrated that the PPT values in general were lower in patients compared with healthy subjects, and this was especially noted for temporalis in both females (migraine: 231.2 ± 38.3 kPa < TTH: 248.4 ± 39.3 kPa < healthy: 282.1 ± 70.8 kPa) and males (migraine: 225.5 ± 61.2 kPa < TTH: 264.2 ± 32.5 kPa < healthy: 314.8 ± 63.3 kPa). The masseter muscle seemed to be more sensitive than the other 2 muscles, in both females (healthy: masseter 194.1 ± 62.7 kPa < frontalis 277.5 ± 51.1 kPa < temporalis 282.1 ± 70.8 kPa) and males (healthy: masseter 248.2 ± 48.4 kPa < temporalis 314.8 ± 63.3 < frontalis 388 kPa). Females had lower PPT values than those of males in temporalis, masseter, and frontalis muscles. This work is the first to systematically review the scientific literature addressing PPT values over craniofacial muscles of healthy subjects, patients with TTH, and those with migraine to provide the PPT value ranges. Based on these findings, a set of guidelines was established to assist future studies including PPT assessments over craniofacial muscles.

  18. 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. © 2014 John Wiley & Sons Ltd.

  19. Relationship between Occlusal Force Distribution and the Activity of Masseter and Anterior Temporalis Muscles in Asymptomatic Young Adults

    PubMed Central

    Wieczorek, Aneta; Loster, Bartlomiej W.

    2013-01-01

    Healthy subjects have a prevalent side on which they display higher-muscle activity during clenching. The relationship between symmetry of masseter muscle (MM) and anterior temporalis (TA) muscle activities and occlusion has been evaluated on the basis of physiological parameters. The aim of the present study was to investigate whether the symmetry of surface EMG (sEMG) activity in asymptomatic young adults is related to symmetry of occlusal contacts. Material. The study population consisted of seventy-two 18-year-old subjects with no temporomandibular disorder (TMD) symptoms. Method. All the participants underwent an sEMG recording with an 8-channel electromyograph (BioEMG III). A T-Scan III evolution 7.01 device was used to analyze the occlusal contact points. Results. The correlation between the activity of right (R) and left (L) TA and the percentage of occlusal contacts was assessed, but no significant differences were found between the RMM and LMM muscles. The differences in the medium values of sEMG between males and females were not statistically significant. Equilibrated muscular activity between RTA and LTA occurred when occlusal contacts reached the percentage of 65% on the left side. Conclusion. The symmetry of sEMG activity in asymptomatic young adults is not related to symmetry of occlusal contacts. PMID:23509713

  20. The immediate effect of changing mandibular position on the EMG activity of the masseter, temporalis, sternocleidomastoid, and trapezius muscles.

    PubMed

    Ceneviz, Caroline; Mehta, Noshir R; Forgione, Albert; Sands, M J; Abdallah, Emad F; Lobo Lobo, Silvia; Mavroudi, Sofia

    2006-10-01

    This study investigated the immediate effect of changing mandibular position on the electromyographic (EMG) activity of the masseter (MS), temporalis (TM), sternocleidomastoid (SCM) and trapezius (TR) muscles. Thirty-three (33) asymptomatic subjects (16 males and 17 females), ages 23 to 52 were selected. Surface EMG recordings were obtained for all muscles bilaterally with the mandible in a relaxed open position (relaxed) and during maximal voluntary clenching (fullbite) for the following: a non-repositioning appliance (NONREPOS) and repositioning appliance (REPOS). REPOS significantly reduced EMG activity of all muscles bilaterally during fullbite. During relaxation, reduction in EMG activity was only found for TR bilaterally. NONREPOS decreased the EMG activity bilaterally for TM and TR and unilaterally (left) for MS and SCM during fullbite. During relaxation, NONREPOS decreased muscle activity bilaterally for TR and SCM. A unilateral reduction was found for TM (right). These findings suggest that immediate alterations in mandibular position affect the cranio-cervical system. Both mandibular positions tested lowered the EMG activity of masticatory and cervical muscles in the relaxed and fullbite positions. The trapezius muscle was the most responsive to alterations in mandibular position.

  1. Assessment of cross-sectional thickness and activity of masseter, anterior temporalis and orbicularis oris muscles in oral submucous fibrosis patients and healthy controls: an ultrasonography and electromyography study.

    PubMed

    Kant, P; Bhowate, R R; Sharda, N

    2014-01-01

    Oral submucous fibrosis (OSMF) is an insidious chronic disease that is associated with significant functional morbidity and an increased risk for malignancy. It initially affects the lamina propria of the oral mucosa, and, as the disease progresses, it involves the submucosa and deeper tissue, including muscles of the oral cavity, resulting in loss of fibroelasticity. OSMF is a pre-malignant condition mainly caused by areca nut chewing. The aim of this study was to find out the involvement of muscles of mastication and facial expression in patients with OSMF by assessing the cross-sectional thickness and activity of the masseter, anterior temporalis and orbicularis oris muscles by ultrasonography and electromyography and comparing with healthy controls and also to find out any correlation between the ultrasonographic cross-sectional thicknesses of the masseter, anterior temporalis and orbicularis oris muscles with electromyographic activity. 40 patients with OSMF were included in the study group, and the patients were divided into four groups on the basis of interincisal mouth opening, i.e. Group I (mouth opening >35 mm), Group II (mouth opening between 30 and 35 mm), Group III (mouth opening between 20 and 30 mm) and Group IV (mouth opening <20 mm). Ultrasonographic cross-sectional thickness and electromyographic activity (amplitude and duration) of the masseter, anterior temporalis and orbicualris oris muscles were recorded in patients with OSMF and 20 controls. Intergroup comparison of ultrasonographic cross-sectional thickness and activity (amplitude and duration) was done, and Pearson's correlation coefficient was applied to find out any relation between ultrasonographic and electromyographic findings. Thickness and activity of the masseter muscle was significantly reduced in Group IV (mouth opening <20 mm) when compared with the control group. The anterior temporalis and orbicularis oris muscles remained unaffected. A positive correlation was

  2. Assessment of cross-sectional thickness and activity of masseter, anterior temporalis and orbicularis oris muscles in oral submucous fibrosis patients and healthy controls: an ultrasonography and electromyography study

    PubMed Central

    Bhowate, R R; Sharda, N

    2014-01-01

    Objectives: Oral submucous fibrosis (OSMF) is an insidious chronic disease that is associated with significant functional morbidity and an increased risk for malignancy. It initially affects the lamina propria of the oral mucosa, and, as the disease progresses, it involves the submucosa and deeper tissue, including muscles of the oral cavity, resulting in loss of fibroelasticity. OSMF is a pre-malignant condition mainly caused by areca nut chewing. The aim of this study was to find out the involvement of muscles of mastication and facial expression in patients with OSMF by assessing the cross-sectional thickness and activity of the masseter, anterior temporalis and orbicularis oris muscles by ultrasonography and electromyography and comparing with healthy controls and also to find out any correlation between the ultrasonographic cross-sectional thicknesses of the masseter, anterior temporalis and orbicularis oris muscles with electromyographic activity. Methods: 40 patients with OSMF were included in the study group, and the patients were divided into four groups on the basis of interincisal mouth opening, i.e. Group I (mouth opening >35 mm), Group II (mouth opening between 30 and 35 mm), Group III (mouth opening between 20 and 30 mm) and Group IV (mouth opening <20 mm). Ultrasonographic cross-sectional thickness and electromyographic activity (amplitude and duration) of the masseter, anterior temporalis and orbicualris oris muscles were recorded in patients with OSMF and 20 controls. Intergroup comparison of ultrasonographic cross-sectional thickness and activity (amplitude and duration) was done, and Pearson's correlation coefficient was applied to find out any relation between ultrasonographic and electromyographic findings. Results: Thickness and activity of the masseter muscle was significantly reduced in Group IV (mouth opening <20 mm) when compared with the control group. The anterior temporalis and orbicularis oris muscles remained unaffected. A

  3. Quantitative analysis of masseter and temporalis EMGs: a comparison of anterior guided versus balanced occlusal concepts in patients wearing complete dentures.

    PubMed

    Grubwieser, G; Flatz, A; Grunert, I; Kofler, M; Ulmer, H; Gausch, K; Kulmer, S

    1999-09-01

    The lack of easily measurable, objective physiological activity parameters of the masseter and temporalis muscle during jaw movements in humans has led to the consideration to revise data of surface electromyographies (EMGs) by applying a computerized quantification method. The aim of this follow-up analysis was to get quantitative data out of EMG-records of an earlier study. These records were obtained with two different splints, splint 1 providing an anterior front-canine guidance and splint 2 providing bilateral balanced occlusion. Utilizing a computer aided integration method led to numeric results which statistically proves the prediction of the previous investigation. Applying the integration method, the EMG raw signal was transformed into area-values which enabled a statistical work up of the data. Wilcoxon test statistics shows a significant (P<0.05) lower muscle activity in patients wearing dentures providing anterior front-canine guidance compared to those with balanced occlusion. It is concluded that the neuromuscular activity of the elevator muscles is highly reproducible and that the neuromuscular function is similar in edentulous subjects to that found in people with natural teeth. Furthermore, the study statistically proves earlier visual data that all those subjects, whose muscle activities were observed with anterior guidance (splint 1) compared to bilateral balanced occlusion (splint 2) showed significantly lower values with regard to subjects wearing splint 2.

  4. Temporalis function in anthropoids and strepsirrhines: an EMG study.

    PubMed

    Hylander, William L; Wall, Christine E; Vinyard, Christopher J; Ross, Callum; Ravosa, Mathew R; Williams, Susan H; Johnson, Kirk R

    2005-09-01

    The major purpose of this study is to analyze anterior and posterior temporalis muscle force recruitment and firing patterns in various anthropoid and strepsirrhine primates. There are two specific goals for this project. First, we test the hypothesis that in addition to transversely directed muscle force, the evolution of symphyseal fusion in primates may also be linked to vertically directed balancing-side muscle force during chewing (Hylander et al. [2000] Am. J. Phys. Anthropol. 112:469-492). Second, we test the hypothesis of whether strepsirrhines retain the hypothesized primitive mammalian condition for the firing of the anterior temporalis, whereas anthropoids have the derived condition (Weijs [1994] Biomechanics of Feeding in Vertebrates; Berlin: Springer-Verlag, p. 282-320). Electromyographic (EMG) activities of the left and right anterior and posterior temporalis muscles were recorded and analyzed in baboons, macaques, owl monkeys, thick-tailed galagos, and ring-tailed lemurs. In addition, as we used the working-side superficial masseter as a reference muscle, we also recorded and analyzed EMG activity of the left and right superficial masseter in these primates. The data for the anterior temporalis provided no support for the hypothesis that symphyseal fusion in primates is linked to vertically directed jaw muscle forces during mastication. Thus, symphyseal fusion in primates is most likely mainly linked to the timing and recruitment of transversely directed forces from the balancing-side deep masseter (Hylander et al. [2000] Am. J. Phys. Anthropol. 112:469-492). In addition, our data demonstrate that the firing patterns for the working- and balancing-side anterior temporalis muscles are near identical in both strepsirrhines and anthropoids. Their working- and balancing-side anterior temporalis muscles fire asynchronously and reach peak activity during the power stroke. Similarly, their working- and balancing-side posterior temporalis muscles also fire

  5. Masseter tenomyositis.

    PubMed

    DuPont, John S; Brown, Christopher E

    2009-07-01

    The masseter muscle is an integral part of the oral facial complex and one of the muscles of mastication. It functions with the other masticatory muscles in moving and posturing the mandible and in verbalizing, eating and swallowing. When a patient has temporomandibular dysfunction (TMD) or a myogenic disorder, the integrity of the masseter muscle can be compromised resulting in pain, malfunction, inflammation and/or swelling. A careful evaluation of the masseter muscles is necessary in facial pain patients since the pain can originate from a distant site and be referred to this area. One of the little known disorders involving the masseter and its tendinous origin is tenomyositis, in which an inflammation of the muscle and its tendon occurs. In this retrospective study, the charts of 114 consecutive patients (N = 114) were evaluated to determine the prevalence of this disorder and the reported etiology.

  6. Functional organization of the human masseter muscle.

    PubMed

    Gaudy, J F; Zouaoui, A; Bravetti, P; Charrier, J L; Guettaf, A

    2000-01-01

    The authors carried out an anatomic and magnetic resonance imaging study of the architecture of the elevator muscles of the mandible in 169 cadavers. The aim of this study was to define the architectural organization of the human masseter muscle, temporalis and pterygoid muscles. Layered dissections and anatomic sections in different spatial planes showed that the masseter muscle exhibited a typical pennate structure consisting of a succession of alternating musculoaponeurotic layers. The muscle had three well-differentiated parts: the superficial, intermediate and deep masseter muscles. The same pattern was constantly found: 1) for the superficial masseter, two alternate musculoaponeurotic layers oriented at 60 degrees in relation to the plane of occlusion, 2) for the intermediate masseter, a single musculo-aponeurotic layer oriented at 90 degrees in relation to the occlusal plane, 3) for the deep masseter, three musculoaponeurotic layers whose general orientation was at 90 degrees for the bounding layers and 110 degrees for the intermediate layer. The MRI study confirmed the reality of this architectural arrangement.

  7. A rare variation of the digastric muscle

    PubMed Central

    KALNIEV, MANOL; KRASTEV, DIMO; KRASTEV, NIKOLAY; VIDINOV, KALIN; VELTCHEV, LUDMIL; APOSTOLOV, ALEXANDER; MILEVA, MILKA

    2013-01-01

    The digastric muscle is composed by two muscle bellies: an anterior and a posterior, joined by an intermediate tendon. This muscle is situated in the anterior region of the neck. The region between the hyoid bone and the mandible is divided by an anterior belly into two triangles: the submandibular situated laterally and the submental triangle which is located medially. We found that the anatomical variations described in the literature relate mainly to the anterior belly and consist of differences in shape and attachment of the muscle. During routine dissection in February 2013 in the section hall of the Department of Anatomy and Histology in Medical University – Sofia we came across a very interesting variation of the digastric muscle. The digastric muscles that presented anatomical variations were photographed using a Sony Cyber-shot DSC-T1 camera, with a Carl Zeiss Vario-Tessar lens. We found out bilateral variation of the digastric muscle in one cadaver. The anterior bellies were very thin and insert to the hyoid bone. Two anterior bellies connect each other and thus they formed a loop. The anatomical variations observed of our study related only to the anterior belly, as previously described by other authors. It is very important to consider the occurrence of the above mentioned variations in the digastric muscle when surgical procedures are performed on the anterior region of the neck. PMID:26527971

  8. Masseter and medial pterygoid muscle hypertrophy.

    PubMed

    Guruprasad, R; Rishi, Sudhirkumar; Nair, Preeti P; Thomas, Shaji

    2011-09-26

    Hypertrophy refers to an enlargement caused by an increase in the size but not in the number of cells. Generalised masticatory muscle hypertrophy may affect the temporalis muscle, masseters and medial pterygoids in a variety of combinations. Masseteric hypertrophy may present as either unilateral or bilateral painless swelling of unknown origin in the region of angle of mandible. It is a relatively rare condition and presents a diagnostic dilemma. While the history and clinical examination are important in differentiating this benign condition from parotid or dental pathology, they cannot necessarily exclude rare malignant lesion within the muscle. Advanced imaging modalities like CT and MRI are essential to confirm the diagnosis. Here the authors are reporting a unique case of masseter muscle hypertrophy along with medial pterygoid hypertrophy which was missed clinically but confirmed using CT and MRI.

  9. Masseter and medial pterygoid muscle hypertrophy

    PubMed Central

    R, Guruprasad; Rishi, Sudhirkumar; Nair, Preeti P; Thomas, Shaji

    2011-01-01

    Hypertrophy refers to an enlargement caused by an increase in the size but not in the number of cells. Generalised masticatory muscle hypertrophy may affect the temporalis muscle, masseters and medial pterygoids in a variety of combinations. Masseteric hypertrophy may present as either unilateral or bilateral painless swelling of unknown origin in the region of angle of mandible. It is a relatively rare condition and presents a diagnostic dilemma. While the history and clinical examination are important in differentiating this benign condition from parotid or dental pathology, they cannot necessarily exclude rare malignant lesion within the muscle. Advanced imaging modalities like CT and MRI are essential to confirm the diagnosis. Here the authors are reporting a unique case of masseter muscle hypertrophy along with medial pterygoid hypertrophy which was missed clinically but confirmed using CT and MRI. PMID:22679271

  10. Feasibility of eliciting the H reflex in the masseter muscle in patients under general anesthesia.

    PubMed

    Ulkatan, Sedat; Jaramillo, Ana Maria; Téllez, Maria J; Goodman, Robert R; Deletis, Vedran

    2017-01-01

    To explore the feasibility of eliciting the brainstem H reflex in the masseter muscle in patients under general anesthesia. We electrically stimulated the masseteric nerve, a branch of the trigeminal nerve, and recorded ipsilateral masseteric and temporalis muscle responses. We tested eight patients who presented with trigeminal neuralgia; one patient had a temporal bone tumor and one patient had a brainstem arteriovenous malformation. All responses were elicited when patients were under general anesthesia and before the initiation of surgery. The H reflex in the masseter muscle was reliably elicited in 70% of the patients. The reflexes met the usual criteria for the H reflex because they were elicited below the threshold of the direct M response, and their amplitudes decreased when the M response increased with stronger stimuli. The mean onset latencies of the masseter H reflex and the M response were 5.4±1.3ms and 2.6±0.6ms, respectively. In the present study, we provide evidence of the feasibility of eliciting the H reflex in the masseter muscles of patients under general anesthesia. The H reflex of the masseter muscle may represent a new method available for intraoperative monitoring. Specifically, this method may be important for the monitoring of brainstem functional integrity, particularly in the midbrain and mid-pons, in addition to the trigeminal nerve path. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  11. 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.

  12. Botulinum toxin for masseter hypertrophy.

    PubMed

    Al-Muharraqi, Mohammed A; Fedorowicz, Zbys; Al Bareeq, Jaffer; Al Bareeq, Reem; Nasser, Mona

    2009-01-21

    Benign masseter muscle hypertrophy is an uncommon clinical phenomenon of uncertain aetiology which is characterised by a soft swelling near the angle of the mandible. The swelling may on occasion be associated with facial pain and can be prominent enough to be considered cosmetically disfiguring. Varying degrees of success have been reported for some of the treatment options for masseter hypertrophy, which range from simple pharmacotherapy to more invasive surgical reduction. Injection of botulinum toxin type A into the masseter muscle is generally considered a less invasive modality and has been advocated for cosmetic sculpting of the lower face. Botulinum toxin type A is a powerful neurotoxin which is produced by the anaerobic organism Clostridium botulinum and when injected into a muscle causes interference with the neurotransmitter mechanism producing selective paralysis and subsequent atrophy of the muscle. To assess the effects of botulinum toxin type A in the management of benign bilateral masseter hypertrophy. We searched the following databases in August 2008: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, issue 3); MEDLINE (via PubMed) (1950 to August 2008); EMBASE (via embase.com) (1980 to August 2008); and LILACS via BIREME. We searched two bibliographic databases of regional journals which may be expected to contain relevant trials (IndMED and Iranmedex) using free text terms appropriate for this review. Randomised controlled clinical trials (RCTs) and controlled clinical trials (CCTs) comparing intra-masseteric injections of botulinum toxin versus placebo administered for cosmetic facial sculpting in individuals of any age with bilateral benign masseter hypertrophy, which had been self-evaluated and confirmed by clinical and radiological examination. We excluded participants with unilateral or compensatory contralateral masseter hypertrophy resulting from head and neck radiotherapy. Two review authors

  13. Observational study on the occurrence of muscle spindles in human digastric and mylohyoideus muscles.

    PubMed

    Saverino, Daniele; De Santanna, Amleto; Simone, Rita; Cervioni, Stefano; Cattrysse, Erik; Testa, Marco

    2014-01-01

    Although the occurrence of muscle spindles (MS) is quite high in most skeletal muscles of humans, few MS, or even absence, have been reported in digastric and mylohyoideus muscles. Even if this condition is generally accepted and quoted in many papers and books, observational studies are scarce and based on histological sections of a low number of specimens. The aim of the present study is to confirm previous data, assessing MS number in a sample of digastric and mylohyoideus muscles. We investigated 11 digastric and 6 mylohyoideus muscles from 13 donors. Muscle samples were embedded in paraffin wax, cross-sectioned in a rostrocaudal direction, and stained using haematoxylin-eosin. A mean of 5.1 ± 1.1 (range 3-7) MS was found in digastric muscles and mean of 0.5 ± 0.8 (range 0-2) in mylohyoideus muscles. A significant difference (P < 0.001) was found with the control sample, confirming the correctness of the histological procedure. Our results support general belief that the absolute number of spindles is sparse in digastric and mylohyoideus muscles. External forces, such as food resistance during chewing or gravity, do not counteract jaw-opening muscles. It is conceivable that this condition gives them a limited proprioceptive importance and a reduced need for having specific receptors as MS.

  14. Effect of genioglossus, geniohyoid, and digastric advancement on tongue base and hyoid position.

    PubMed

    Kutzner, Emily A; Miot, Christelle; Liu, Yuan; Renk, Elizabeth; Park, Joshua S; Inman, Jared C

    2017-08-01

    To assess the effect of genioglossus, geniohyoid, and anterior digastric muscle advancement on base of tongue and hyoid position. Cadaver experiments. In fresh cadavers, the mandibular attachments of the genioglossus, geniohyoid, and anterior digastric muscles were advanced anteriorly by 6, 10, or 14 mm, and the anterior displacement of the base of tongue and hyoid was measured. The degrees of displacement of the tongue base and hyoid by the individual muscles and combinations of muscles were compared to one another. In 11 cadavers, 462 measurements were taken. Genioglossus advancement alone produced significantly greater tongue base advancement than any other muscle (P < .001). No combination of muscles produced significantly more tongue base advancement than the genioglossus alone. Geniohyoid (P < .001) and anterior digastric muscle (P < .001) advancement both produced significantly greater hyoid advancement than the genioglossus, but there was no difference between the two (p = .615). No combination of muscles produced significantly more hyoid advancement than the geniohyoid or anterior digastric alone. Genioglossus muscle advancement produces the greatest base of tongue advancement. Geniohyoid or anterior digastric muscle advancement produces the greatest hyoid advancement. Advancement of neither base of tongue nor hyoid was superior when combinations of muscles were moved. NA Laryngoscope, 127:1938-1942, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  15. Observational Study on the Occurrence of Muscle Spindles in Human Digastric and Mylohyoideus Muscles

    PubMed Central

    De Santanna, Amleto; Cervioni, Stefano

    2014-01-01

    Although the occurrence of muscle spindles (MS) is quite high in most skeletal muscles of humans, few MS, or even absence, have been reported in digastric and mylohyoideus muscles. Even if this condition is generally accepted and quoted in many papers and books, observational studies are scarce and based on histological sections of a low number of specimens. The aim of the present study is to confirm previous data, assessing MS number in a sample of digastric and mylohyoideus muscles. We investigated 11 digastric and 6 mylohyoideus muscles from 13 donors. Muscle samples were embedded in paraffin wax, cross-sectioned in a rostrocaudal direction, and stained using haematoxylin-eosin. A mean of 5.1 ± 1.1 (range 3–7) MS was found in digastric muscles and mean of 0.5 ± 0.8 (range 0–2) in mylohyoideus muscles. A significant difference (P < 0.001) was found with the control sample, confirming the correctness of the histological procedure. Our results support general belief that the absolute number of spindles is sparse in digastric and mylohyoideus muscles. External forces, such as food resistance during chewing or gravity, do not counteract jaw-opening muscles. It is conceivable that this condition gives them a limited proprioceptive importance and a reduced need for having specific receptors as MS. PMID:25165696

  16. Masseter function and skeletal malocclusion.

    PubMed

    Sciote, J J; Raoul, G; Ferri, J; Close, J; Horton, M J; Rowlerson, A

    2013-04-01

    The aim of this work is to review the relationship between the function of the masseter muscle and the occurrence of malocclusions. An analysis was made of the masseter muscle samples from subjects who underwent mandibular osteotomies. The size and proportion of type-II fibers (fast) decreases as facial height increases. Patients with mandibular asymmetry have more type-II fibers on the side of their deviation. The insulin-like growth factor and myostatin are expressed differently depending on the sex and fiber diameter. These differences in the distribution of fiber types and gene expression of this growth factor may be involved in long-term postoperative stability and require additional investigations. Muscle strength and bone length are two genetically determined factors in facial growth. Myosin 1H (MYOH1) is associated with prognathia in Caucasians. As future objectives, we propose to characterize genetic variations using "Genome Wide Association Studies" data and their relationships with malocclusions.

  17. Bleb Revision With Temporalis Fascia Autograft.

    PubMed

    Qu-Knafo, Lise; Le Du, Brivael; Boumendil, Julien; Nordmann, Jean-Philippe

    2017-01-01

    We report the first description of temporalis fascia autograft to repair a late leakage bleb with scleral defect that occurred long time after trabeculectomy with mitomycin C. A 65-year-old woman was referred to our hospital with chronic late bleb leakage on her right eye. She had previously undergone a trabeculectomy with mitomycin C 3 years ago for a pigmentary glaucoma. Bleb leakage occurred 1½ year after the initial surgery. She underwent 2 surgical revisions consisting of a conjunctival advancement then an autologous conjunctival with partial scleral grafts without success. The initial best-corrected visual acuity of the right eye was 20/50 (Snellen scale). Slit-lamp examination revealed an avascular filtering bleb with leakage (massive positive Seidel test) and a scleral defect. The anterior chamber was deep and intraocular pressure (IOP) was 9 mm Hg.Faced with the risk of blebitis, endophthalmitis, and with the failure of the previous surgeries announced earlier, a surgical revision with autologous superficial temporalis fascia graft was decided to repair the leaking bleb. After local anesthesia, a sample of superficial temporalis fascia was harvested. The necrotic avascular conjunctiva around the bleb was dissected to separate and excise it from the sclera. The autologous fascia graft was sutured on the scleral defect with 10-0 nylon. Subsequently healthy conjunctiva was sutured above the graft. No bleb leakage occurred postoperatively, best-corrected visual acuity improved to 20/25, and IOP remained within normal levels 6 months after surgery without IOP-lowering medication. Superficial temporalis fascia autograft seems to be an effective, safe, and easy technique for ophthalmologists. It is a new procedure in the management of late-onset bleb leakage.

  18. Muscle response to the twin-block appliance: an electromyographic study of the masseter and anterior temporal muscles.

    PubMed

    Aggarwal, P; Kharbanda, O P; Mathur, R; Duggal, R; Parkash, H

    1999-10-01

    An electromyographic study was performed on 10 young growing girls in the age group of 9 to 12 years with Class II Division 1 malocclusion and retruded mandible, who were under treatment with Twin-block appliances. Bilateral EMG activity of elevator muscles of the mandible (ie, anterior temporalis and masseter) was monitored longitudinally with bipolar surface electrodes to determine changes in postural, swallowing, and maximal voluntary clenching activity during an observation period of 6 months. The changes were noted at the start of treatment (0 month), within 1 month of Twin-block insertion, at the end of 3 months, and at the end of 6 months. The results revealed a significant increase in postural and maximal clenching EMG activity in masseter (P <.01) and a numeric increase in anterior temporalis activity during the 6 month period of treatment. The increased electromyographic activity can be attributed to an enhanced stretch (myotatic) reflex of the elevator muscles, contributing to isometric contractions. The main force for Twin-block treatment appears to be provided through increased active tension in the stretched muscles (motor unit stimulation) and from initiation of myotatic reflex activity and not through passive tension (viscoelastic properties) of jaw muscles. The results of this study reaffirm the importance of full-time wear for functional appliances to exert their maximum therapeutic effect by way of neuromuscular adaptation.

  19. 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

  20. Use of the temporalis muscule flap in blanking out orbits.

    PubMed

    Holmes, A D; Marshall, K A

    1979-03-01

    We report the use of the temporalis muscle as a transposition flap to obliterate the orbit in 5 patients. In 4 of the cases we split the muscle coronally and passed the anterior part through a window in the lateral orbital wall. In two of these patients, skin grafts were put on both sides of the temporalis muscle-fascia flap, to restore nasal lining and to cover the facial surface simultaneously. In the remaining patients, the muscle was split sagittally to provide a large surface for coverage. The temporalis muscle flap is a versatile one for filling orbits after exenteration.

  1. 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.

  2. Voluntary and reflex control of the human temporalis muscle.

    PubMed

    Scott, B J J; Mason, A G; Cadden, S W

    2002-07-01

    Electromyographic recordings (EMGs) were made in 10 human subjects from the anterior and posterior parts of the temporalis muscle using skin surface electrodes. The activities produced by voluntary maximal clenching tasks and the reflex responses to electrical stimulation of the muco-gingival junction were studied. In most subjects, maximum activity in both parts of the muscle occurred when clenching in the intercuspal position (anterior temporalis: 7 of 10 subjects; posterior temporalis: 9 of 10 subjects). Clenching maximally in the retruded position usually resulted in less activity; when this activity was expressed as a percentage of the maximum achieved by each subject for that part of the muscle, the median values were: anterior temporalis, 68% and posterior temporalis, 79%. Clenching in the protruded position produced little or no activity (median values: anterior temporalis, 3%; posterior temporalis, 5%). There were no significant differences between the EMG activities of the anterior and posterior parts of the muscle during these tasks when the activities were normalized to the maximum achieved in each part of the muscle. Application of electrical stimuli at the muco-gingival junction (upper incisor region) produced reflex inhibitions and excitations in both parts of the muscle. There were no significant differences in the thresholds of these reflexes between the anterior and posterior parts of the muscle. Furthermore, there was little difference between the two parts of the muscle in terms of the latencies, durations and magnitudes of the responses. Thus the results of the study suggest that there are similar neural control mechanisms for the anterior and posterior parts of the temporalis muscle despite the common view that these parts of the muscle have different functions.

  3. Development of digastric muscles in human fetuses: a review and findings in the flexor digitorum superficialis muscle.

    PubMed

    Rodríguez-Vázquez, José Francisco; Jin, Zhe Wu; Zhao, Peng; Murakami, Gen; Li, Xiang Wu; Jin, Yu

    2017-09-04

    The digastricus and omohyoideus muscles are digastric muscles with two muscle bellies. An insertion tendon of the posterior belly becomes an intermediate tendon in digastricus muscles, whereas a single band-like muscle in omohyoideus muscles may later be interrupted by an intermediate tendon, possibly due to muscle cell death caused by mechanical stress. In human fetuses, an intermediate tendon provides the temporal origins of the tensor veli palatini and tensor tympani muscles. Some reptiles, including snakes, carry multiple series of digastric-like axial muscles, in which each intersegmental septum is likely to become an intermediate tendon. These findings indicate that many pathways are involved in the development of digastric muscles. A review of these morphologies suggested that the flexor digitorum superficialis (FDS) muscle was a digastric muscle, although the intermediate tendon may not be visible in the surface view in adults. The present observations support the hypothesis that the proximal anlage at the elbow develops into a deep muscle slip to a limited finger, while the distal anlage at the wrist develops into the other slips. The findings suggest that, in the FDS muscle, the proximal and distal bellies of the embryonic digastric muscle fuse together to form a laminar structure, in which muscle slips accumulate from the palmar to the deep side of the forearm.

  4. Reflex responses of masseter muscles to sound.

    PubMed

    Deriu, Franca; Giaconi, Elena; Rothwell, John C; Tolu, Eusebio

    2010-10-01

    Acoustic stimuli can evoke reflex EMG responses (acoustic jaw reflex) in the masseter muscle. Although these were previously ascribed to activation of cochlear receptors, high intensity sound can also activate vestibular receptors. Since anatomical and physiological studies, both in animals and humans, have shown that masseter muscles are a target for vestibular inputs we have recently reassessed the vestibular contribution to masseter reflexes. We found that high intensity sound evokes two bilateral and symmetrical short-latency responses in active unrectified masseter EMG of healthy subjects: a high threshold, early p11/n15 wave and a lower threshold, later p16/n21 wave. Both of these reflexes are inhibitory but differ in their threshold, latency and appearance in the rectified EMG average. Experiments in healthy subjects and in patients with selective lesions showed that vestibular receptors were responsible for the p11/n15 wave (vestibulo-masseteric reflex) whereas cochlear receptors were responsible for the p16/n21 wave (acoustic masseteric reflex). The possible functional significance of the double vestibular control over masseter muscles is discussed. Copyright 2010 International Federation of Clinical Neurophysiology. All rights reserved.

  5. Cysticercosis of the masseter: MRI and sonographic correlation

    PubMed Central

    Nagarjuna, M; Belaval, V; Shetty, S; Salins, P C

    2015-01-01

    Cysticercal involvement of the masseter is an uncommon manifestation of a relatively common parasitic infestation. Sonographic evaluation of many isolated cases of cysticercosis has been extensively described. However, there are scanty reports on MRI appearance of cysticercal involvement of the masseter. This report presents classical imaging appearance of cysticercal involvement of the masseter on sonography and MRI. The pattern of the disease and MRI appearance of lesions in the masseter, highlighting the role of diffusion-weighted images, are described. PMID:25734242

  6. Cysticercosis of the masseter: MRI and sonographic correlation.

    PubMed

    Bhat, V; Nagarjuna, M; Belaval, V; Shetty, S; Salins, P C

    2015-01-01

    Cysticercal involvement of the masseter is an uncommon manifestation of a relatively common parasitic infestation. Sonographic evaluation of many isolated cases of cysticercosis has been extensively described. However, there are scanty reports on MRI appearance of cysticercal involvement of the masseter. This report presents classical imaging appearance of cysticercal involvement of the masseter on sonography and MRI. The pattern of the disease and MRI appearance of lesions in the masseter, highlighting the role of diffusion-weighted images, are described.

  7. Bimaxillary protrusion with masseter muscle hypertrophy treated with titanium screw anchorage and masseter surgical reduction.

    PubMed

    Hashimoto, Takashi; Kuroda, Shingo; Kamioka, Hiroshi; Mishima, Katsuaki; Sugahara, Toshio; Takano-Yamamoto, Teruko

    2009-04-01

    This case report describes the treatment of a patient with bimaxillary protrusion and masseter muscle hypertrophy. At age 21 years 7 months, this woman had temporomandibular disorder (TMD) symptoms, severe bimaxillary protrusion, and a prominent mandibular angle with facial asymmetry. After an attempt to alleviate the TMD symptoms with occlusal splint stabilization, portions of the masseter muscle and the mandible were surgically removed. Titanium screws were placed bilaterally in both arches, and a retraction force was applied. After active treatment for 38 months, the convexity of the facial profile with lip protrusion was improved remarkably, and good occlusion was achieved. The prominent mandibular angle with facial asymmetry was improved as a result of the surgical reduction of the masseter muscle and the modeling ostectomy near the masseteric tuberosity. The TMD symptoms disappeared, and the jaw movement pattern became normal. Therefore, our results suggest that this combination treatment would be useful for masseter muscle hypertrophy for morphologic and functional problems.

  8. The relationship between masseter force and masseter electromyogram during mastication in the monkey Macaca fascicularis.

    PubMed

    Hylander, W L; Johnson, K R

    1989-01-01

    In five adult monkeys, electromyograms (EMGs) were recorded from bipolar surface electrodes positioned over the superficial masseter and from bipolar fine-wire electrodes within both the superficial and deep masseter. Relative masseter force was estimated by measuring surface bone strain from the lateral aspect of the zygomatic arch using rosette strain gauges. Multiple step-wise regression procedures demonstrated that peak values of the averaged masseter EMG could often explain a considerable amount of the variation of peak relative masseter force during mastication, i.e. r2 values ranged from 0.23 to 0.96 for the various single-electrode models and R2 values ranged from 0.78 to 0.96 for the various multiple-electrode models. The r2 values for relative masseter force and EMG data from the surface electrodes ranged from 0.69 to 0.96, and, on average, EMG data from surface electrodes provided somewhat more information about overall relative muscle force than data from fine-wire electrodes. The R2 values for a two-electrode model, consisting of data from surface electrodes over the superficial masseter and fine-wire electrodes in the posterior portion of the deep masseter, ranged from 0.78 to 0.95. The latency between the averaged surface EMG and relative muscle force was determined and the data indicated that the surface EMG usually preceded muscle force. This latency tended to decrease gradually throughout the entire power stroke of mastication. At peak values, the surface EMG preceded muscle force by about 22 ms. Towards the end of the power stroke, i.e. the 25% of peak values during unloading, muscle force may actually precede the average EMG.

  9. Biting intentions modulate digastric reflex responses to sudden unloading of the jaw.

    PubMed

    Johansson, Anders S; Pruszynski, J Andrew; Edin, Benoni B; Westberg, Karl-Gunnar

    2014-09-01

    Reflex responses in jaw-opening muscles can be evoked when a brittle object cracks between the teeth and suddenly unloads the jaw. We hypothesized that this reflex response is flexible and, as such, is modulated according to the instructed goal of biting through an object. Study participants performed two different biting tasks when holding a peanut half stacked on a chocolate piece between their incisors. In one task, they were asked to split the peanut half only (single-split task), and in the other task, they were asked to split both the peanut and the chocolate in one action (double-split task). In both tasks, the peanut split evoked a jaw-opening muscle response, quantified from electromyogram (EMG) recordings of the digastric muscle in a window 20-60 ms following peanut split. Consistent with our hypothesis, we found that the jaw-opening muscle response in the single-split trials was about twice the size of the jaw-opening muscle response in the double-split trials. A linear model that predicted the jaw-opening muscle response on a single-trial basis indicated that task settings played a significant role in this modulation but also that the presplit digastric muscle activity contributed to the modulation. These findings demonstrate that, like reflex responses to mechanical perturbations in limb muscles, reflex responses in jaw muscles not only show gain-scaling but also are modulated by subject intent.

  10. Painful unilateral temporalis muscle enlargement: reactive masticatory muscle hypertrophy.

    PubMed

    Katsetos, Christos D; Bianchi, Michael A; Jaffery, Fizza; Koutzaki, Sirma; Zarella, Mark; Slater, Robert

    2014-06-01

    An instance of isolated unilateral temporalis muscle hypertrophy (reactive masticatory muscle hypertrophy with fiber type 1 predominance) confirmed by muscle biopsy with histochemical fiber typing and image analysis in a 62 year-old man is reported. The patient presented with bruxism and a painful swelling of the temple. Absence of asymmetry or other abnormalities of the craniofacial skeleton was confirmed by magnetic resonance imaging and cephalometric analyses. The patient achieved symptomatic improvement only after undergoing botulinum toxin injections. Muscle biopsy is key in the diagnosis of reactive masticatory muscle hypertrophy and its distinction from masticatory muscle myopathy (hypertrophic branchial myopathy) and other non-reactive causes of painful asymmetric temporalis muscle enlargement.

  11. Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication.

    PubMed

    Pasinato, Fernanda; Santos-Couto-Paz, Clarissa C; Zeredo, Jorge Luis Lopes; Macedo, Sergio Bruzadelli; Corrêa, Eliane C R

    2016-12-01

    The aim of this study was to verify the effects of induced masseter-muscle pain on the amplitude of muscle activation, symmetry and coactivation of jaw- and neck-muscles during mastication. Twenty-eight male volunteers, mean age±SD 20.6±2.0years, participated in this study. Surface electromyography of the masseter and sternocleidomastoid (SCM) muscles was performed bilaterally during mastication of a gummy candy before and after injections of monosodium glutamate solution and isotonic saline solution. As a result, we observed a decrease in the amplitude of activation of the masseter muscle on the working side (p=0.009; d=0.34) and a reduction in the asymmetry between the working and the balancing side during mastication (p=0.007; d=0.38). No changes were observed either on the craniocervical electromyographic variables. In conclusion, experimentally induced pain reduced the masseter muscle activation on the working side, thereby reducing the physiological masseters' recruitment asymmetry between the two sides during mastication. No effects on SCM activity were detected. These results may partly explain the initial maladaptative changes underlying TMD conditions.

  12. Bilateral temporalis muscle hypertrophy--two case reports.

    PubMed

    Kar, Jugal Kishore; Kar, Manoranjan; Maiti, Saswati; Sen, Eva

    2012-05-01

    Isolated idiopathic bilateral temporalis muscle hypertrophy is a very rare clinical entity. It can change the facial appearance that manifests itself as a morphopsychological conflict for the subject, which is termed as 'Minotaur syndrome' in the medical literature. Here one such case is reported. The second patient sought medical attention for fear of malignancy.

  13. Unilateral hypoplasia with contralateral hypertrophy of anterior belly of digastric muscle: a case report.

    PubMed

    Ochoa-Escudero, Martin; Juliano, Amy F

    2016-10-01

    Anomalies of the anterior belly of the digastric muscle (DM) are uncommon. We present a case of hypoplasia of the anterior belly of the left DM with hypertrophy of the anterior belly of the contralateral DM. The importance of recognizing this finding is to differentiate hypoplasia of the anterior belly of the DM from denervation atrophy, and not to confuse contralateral hypertrophy with a submental mass or lymphadenopathy. In denervation atrophy of the anterior belly of the DM, associated atrophy of the ipsilateral mylohyoid muscle is present. Hypertrophy of the anterior belly of the contralateral DM can be differentiated from a submental mass or lymphadenopathy by recognizing its isodensity on computed tomography and isointensity on magnetic resonance imaging to other muscles, without abnormal contrast enhancement.

  14. Involvement of Trigeminal Transition Zone and Laminated Subnucleus Caudalis in Masseter Muscle Hypersensitivity Associated with Tooth Inflammation

    PubMed Central

    Shimizu, Kohei; Matsumoto, Kunihito; Noma, Noboru; Matsuura, Shingo; Ohara, Kinuyo; Komiya, Hiroki; Watase, Tetsuro; Ogiso, Bunnai; Tsuboi, Yoshiyuki; Shinoda, Masamichi; Hatori, Keisuke; Nakaya, Yuka; Iwata, Koichi

    2014-01-01

    A rat model of pulpitis/periapical periodontitis was used to study mechanisms underlying extraterritorial enhancement of masseter response associated with tooth inflammation. Periapical bone loss gradually increased and peaked at 6 weeks after complete Freund’s adjuvant (CFA) application to the upper molar tooth pulp (M1). On day 3, the number of Fos-immunoreactive (IR) cells was significantly larger in M1 CFA rats compared with M1 vehicle (veh) rats in the trigeminal subnucleus interpolaris/caudalis transition zone (Vi/Vc). The number of Fos-IR cells was significantly larger in M1 CFA and masseter (Mass) capsaicin applied (M1 CFA/Mass cap) rats compared with M1 veh/Mass veh rats in the contralateral Vc and Vi/Vc. The number of phosphorylated extracellular signal-regulated kinase (pERK)-IR cells was significantly larger in M1 CFA/Mass cap and M1 veh/Mass cap rats compared to Mass-vehicle applied rats with M1 vehicle or CFA in the Vi/Vc. Pulpal CFA application caused significant increase in the number of Fos-IR cells in the Vi/Vc but not Vc on week 6. The number of pERK-IR cells was significantly lager in the rats with capsaicin application to the Mass compared to Mass-vehicle treated rats after pulpal CFA- or vehicle-application. However, capsaicin application to the Mass did not further affect the number of Fos-IR cells in the Vi/Vc in pulpal CFA-applied rats. The digastric electromyographic (d-EMG) activity after Mass-capsaicin application was significantly increased on day 3 and lasted longer at 6 weeks after pulpal CFA application, and these increase and duration were significantly attenuated by i.t. PD98059, a MEK1 inhibitor. These findings suggest that Vi/Vc and Vc neuronal excitation is involved in the facilitation of extraterritorial hyperalgesia for Mass primed with periapical periodontitis or acute pulpal-inflammation. Furthermore, phosphorylation of ERK in the Vi/Vc and Vc play pivotal roles in masseter hyperalgesia after pulpitis or periapical

  15. Tympanoplasty: does dry or wet temporalis fascia graft matter?

    PubMed

    Singh, G B; Kumar, D; Aggarwal, K; Garg, S; Arora, R; Kumar, S

    2016-08-01

    To evaluate the success rate of dry and wet temporalis fascia grafts in type I underlay tympanoplasty. A prospective, randomised study was conducted. One hundred adult patients (males and females) with chronic suppurative otitis media (mucosal type) were divided into 2 groups of 50 each: one group underwent dry graft tympanoplasty and the other underwent wet graft tympanoplasty. Fibroblast count was calculated in dry and wet grafts. The dry graft and wet graft groups had overall surgical success rates of 82 and 90 per cent, respectively; this finding was not statistically significant. A statistically significant high fibroblast count was observed in wet grafts, but it did not correlate with surgical success. A dry or wet temporalis fascia graft does not influence the outcome of tympanoplasty type I.

  16. Comparative myology of the hominoid cranial base. I. The muscular relationships and bony attachments of the digastric muscle.

    PubMed

    Dean, M C

    1984-01-01

    This paper aims to document accurately the soft tissue anatomy and bony attachments of the posterior belly of the digastric muscle and other closely related muscles in the mastoid region of extant hominoids and fossil hominids. Five wet specimens including individuals of Pan, Gorilla and Pongo were dissected and described. Eight casts of fossil hominid cranial bases were also studied along with measurements and notes made from the same original fossil hominid specimens to assess their soft tissue markings in the light of the findings for the three great apes. The results indicate that whereas the attachment of the posterior belly of the digastric muscle in Homo sapiens is associated with a deep groove or fossa, it originates from a widened area and leaves no bony markings on the cranial base of the three great apes. Following a change in the position of the foramen magnum and the occipital condyles in hominids and H. sapiens the insertion of the posterior belly of the digastric has remained posteriorly positioned but has become compressed into a deep groove. It is likely that this has come about by the displacement of the more medial soft tissue structures which have been moved laterally away from the occipital condyles.

  17. Prevalence of hyperactive digastric muscles during swallowing as measured by electromyography in patients with myofascial pain dysfunction syndrome.

    PubMed

    Goldstein, L B; Last, F C; Salerno, V M

    1997-01-01

    One purpose of this clinical study is to establish a relationship between the hyper activity of the digastric muscles and predisposition of an individual to MPDS (myofacial pain dysfunction syndrome). If a population predisposed to MPD could be identified by an early diagnosis, intervention and treatment could eliminate potential pain in adulthood. Secondly, can the employment of electromyography to aid in the diagnosis of patients with MPD be helpful in establishing a program of prevention and treatment? Thirty-one patients, male and female, were randomly selected from among those routinely diagnosed as having myofascial pain dysfunction syndrome by the dental staff at the Long Island Center for Craniofacial Pain. Eighteen patients who did not experience any symptoms of facial pain comprised the control group in the study. This study demonstrated that the average trace readings which indicate the activity of the digastric muscles, as measured by the electromyogram from patients experiencing facial pain were significantly higher than those from patients without pain symptoms. In every instance, the correlation between facial pain and abnormal swallow patterns which are a cause of hyperactivity of the digastrics was confirmed.

  18. Fine structure of myotendinous junction between the anterior belly of the digastric muscle and intermediate tendon in adults rats.

    PubMed

    Ciena, Adriano Polican; de Almeida, Sonia Regina Yokomizo; Dias, Fernando José; Bolina, Cristina de Sousa; Issa, João Paulo Mardegan; Iyomasa, Mamie Mizusaki; Ogawa, Koichi; Watanabe, Ii-sei

    2012-02-01

    This study analyzed the ultrastructural characteristics of the myotendinous junction (MTJ) between anterior belly of digastrics muscle and the intermediate tendon in adult rats. Six male Wistar rats were used and were anesthetized with an overdose of urethane and sacrificed by intracardiac perfusion with modified Karnovsky solution, postfixed in 1% osmium tetroxide, dehydrated in increasing series of alcohols and embedded in Spurr resin for transmission electron microscopic analysis. Ultrastructural analysis showed conical shape of the fiber extremity in MTJ region, highlighting the presence of numerous mitochondria arranged in groups in the subsarcolemmal and intermyofibrillary regions. Atypical MTJ characteristics were seen interspersed with bundles of collagen fibers. Classic characteristics such as finger-like processes by means of sarcoplasmic projections were observed among interdigitations. Terminals and periphericals bundles of myofibrils showed close relationship with the adjacent muscle fiber's endomysium through lateral junctions. In the distal portion, it was observed that the communication region of microtendons forming the intermediate tendon of digastric muscle, and it can highlight the columns disposition of tenocytes. In conclusion, the MTJ ultrastructure between the anterior belly of digastric muscle and intermediate tendon of adult rats showed classical morphologic descriptions and presented an atypical region revealed by the subspecialization between the myofibrils bundles and collagen fibers in the MTJ region. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. The temporalis muscle flap and temporoparietal fascial flap.

    PubMed

    Lam, Din; Carlson, Eric R

    2014-08-01

    The temporal arterial system provides reliable vascular anatomy for the temporalis muscle flap and temporoparietal fascial flap that can support multiple reconstructive needs of the oral and maxillofacial region. The minimal donor site morbidity and ease of development of these flaps result in their predictable and successful transfer for reconstructive surgery of the oral and maxillofacial region. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Lower Lip Suspension Using Bilateral Temporalis Muscle Flaps and Fascia Lata Grafts

    DTIC Science & Technology

    2012-01-01

    muscle, as in a Gil- lies-type temporalis flap for facial reanimation (Figs. 1 and 2). A strip of muscle measuring 5 cm wide is then raised from superior...formed procedure. DISCUSSION The temporalis muscle is a robust flap, and its transfer has long had a place in the history of facial reanimation ...temporalis turndown flaps for dynamic lower lip reanimation in 1934.4 McLaughlin de- scribed disinsertion of the muscle from the coro- noid through a

  1. Temporalis myo-osseous flap: an experimental study

    SciTech Connect

    Antonyshyn, O.; Colcleugh, R.G.; Hurst, L.N.; Anderson, C.

    1986-03-01

    The present paper investigates the anatomy and vascularization of the temporalis myo-osseous flap. This is a calvarial bone flap that employs temporalis muscle and its distal pericranial extension as a pedicle. In six human cadavers the flap was raised as an island on the anterior deep temporal artery after transecting the zygomatic arch and coronoid process. Maximal mobilization was thus obtained, allowing rotation of the flap into the mouth for intraoral reconstruction. The arc of rotation and potential surgical applications were noted. A comparative study of the temporalis myo-osseous flap and free calvarial bone graft was then conducted in a rabbit model. Vascularization of the calvarial bone flap was confirmed by technetium scintigraphy performed on the first postoperative day. The uptake of fluorochrome labels immediately after transfer verified the adequacy of the periosteal circulation in maintaining viability and new osteoid formation throughout the full thickness of calvarial bone. The transplantation of free calvarial bone grafts was followed by necrosis of most cellular elements. This was demonstrated by an absence of fluorochrome uptake up to 19 days postoperatively and a predominance of empty lacunae and nonviable marrow.

  2. Masseter muscle tension and chewing ability in older persons.

    PubMed

    Ohara, Yuki; Hirano, Hirohiko; Watanabe, Yutaka; Edahiro, Ayako; Sato, Emiko; Shinkai, Shoji; Yoshida, Hiroto; Mataki, Shiro

    2013-04-01

    Mastication is an important function to maintain, not only for oral health, but also for quality of life. An easy-to-use method to evaluate the chewing ability of elderly people in any environment is necessary. Few studies have discussed the effectiveness of the masseter muscle by palpation. The purpose of this study was to clarify the availability of masseter muscle tension assessment methods by investigating its relationship with oral health status, and comparing it with other methods of assessing chewing ability. This cross-sectional study was carried out with 547 community-dwelling elderly subjects (246 men and 301 women; mean age 73.8 ± 6.2 years) who participated in a comprehensive annual geriatric health examination in 2010 at Kusatsu, Gunma, Japan. Chewing ability was evaluated by masseter muscle tension palpation, differences of masseter muscle thickness, occlusal force, self-reported chewing ability, and the number of remaining and functional teeth. Masseter muscle thickness was measured by ultrasonography. Masseter muscle thickness and occlusal force showed significant differences between males and females. The strength of masseter muscle tension palpation was significantly associated with men's occlusal force, masseter muscle thickness, the number of remaining and functional teeth, and self-reported chewing ability (P < 0.05). Female participants showed a significant association with occlusal force, masseter muscle thickness, the number of remaining teeth, and self-reported chewing ability and results of palpation (P < 0.05). These results showed that the palpation of masseter muscle tension is a reliable and easy-to-use method to evaluate the chewing ability of elderly people. © 2012 Japan Geriatrics Society.

  3. Masseter reflex in childhood and adolescence.

    PubMed

    Koehler, Jürgen; Hölker, Cordula

    2004-05-01

    We report normative data of masseter reflex from a group of 54 children 2-16 years of age. For statistical analysis, the patients were divided into five age groups: 2-4, 5-7, 8-10, 11-13, and 14-16 years of age. A tap to the chin, using a hammer with a trigger device, elicited the masseter reflex. The response was recorded by surface electrodes. The onset latency and peak-to-peak amplitude of the averaged curve of eight reflex responses were measured. The reflex response could be recorded in all children and adolescents of all groups. The mean latency shortened from age 2 to 7 and was stable at the age of 8 years. As a sign of maturation, the increase of amplitude corresponded to the shortening of latency and was also stable at the age of 8 years. Abnormal side differences in latency of 0.9 ms (age group 2-4 years), 1.1 ms (age group 5-7 years), and 0.8 ms (age group 8-16 years) were evaluated. An amplitude ratio (lower amplitude divided by higher one) above 0.33 was calculated as normal.

  4. Traumatic myositis ossificans in the masseter muscle.

    PubMed

    Arima, R; Shiba, R; Hayashi, T

    1984-08-01

    Traumatic myositis ossificans in the left masseter muscle of a 25-year-old man is described. The lesion, which extended intramuscularly from the lateral surface of the zygomatic bone to the mandibular angle, was resected by an intraoral approach. The specimen was composed of mature cortical bone in the outer portion and spongy bone, including degenerated muscle fibers and marrow spaces, in the inner portion. At the lower end of the specimen was a sequence of bone formation involving fibrous connective tissue, cartilage, woven bone, and mature lamellar bone with many osteoblasts. Clinicopathologic features of 26 reported cases of traumatic myositis ossificans of the maxillofacial region are reviewed, and the pathogenesis of the disease is discussed.

  5. Proliferative myositis of the masseter muscle.

    PubMed

    Scher, N; Dobleman, T J; Poe, D S; Panje, W R

    1987-05-01

    The authors present a case of a 33-year-old white man with a 4-month history of a rapidly enlarging, tender, painful, circumscribed facial mass located in the masseter muscle. CT scan and fine needle aspiration cytology, coupled with clinical assessment, suggested the diagnosis of proliferative myositis. Curative intraoral excisional biopsy was done, thereby avoiding a parotidectomy incision and approach to the lesion. The pathology showed proliferative myositis. A review of the literature revealed 36 cases which indicated that proliferative myositis is a relatively rare etiology of a head and neck mass. Careful clinical, radiologic, and pathologic evaluations were required to make this unusual diagnosis and avoid any unnecessary facial mutilation in its treatment.

  6. Treatment of temporomandibular joint ankylosis with temporalis muscle and fascia flap.

    PubMed

    Su-Gwan, K

    2001-06-01

    This study sought to determine the efficacy of interpositional arthroplasty with temporalis muscle and fascia flap in the treatment of unilateral temporomandibular joint (TMJ) ankylosis in adults. This retrospective study of seven cases evaluated the postoperative results of interpositional arthroplasty on temporalis muscle and fascia flap in adults. The operative protocol for unilateral TMJ ankylosis entailed, (1) resection of ankylotic mass, (2) intraoral ipsilateral coronoidectomy, (3) contralateral coronoidectomy when necessary, (4) interpositional tissue transfer to the TMJ with temporalis muscle and fascia flap, (5) maxillomandibular fixation (MMF), and (6) early mobilization and aggressive physiotherapy. The results of this protocol were encouraging, while the functional results of interpositional arthroplasty on temporalis muscle and fascia flap were satisfactory. The findings of this study support the use of temporalis muscle and fascia flap in adult patients with unilateral TMJ ankylosis. Early postoperative initial exercise, physiotherapy, and strict follow-up play an important role in preventing postoperative adhesions.

  7. Lengthening Temporalis Myoplasty: Virtual Animation-Assisted Technical Video.

    PubMed

    Aljudaibi, Nawaf; Bennis, Yasmine; Duquennoy-Martinot, Veronique; Labbé, Daniel; Guerreschi, Pierre

    2016-09-01

    Lengthening temporalis myoplasty is a well-established procedure for dynamic palliative reanimation of the lip in facial palsy sequelae. The particularity of this technique is that the entire temporal muscle is transferred from the coronoid process to the upper half of the lip without interposition of aponeurotic tissue. To date, no video describing the technique was available. This is the first video describing the entire procedure, from preoperative markings through postoperative rehabilitation. In the video presented herein, the authors craft virtual three-dimensional animations in addition to a live operation on a patient performed by Daniel Labbé, who first described this technique 20 years ago.

  8. Bilateral masseter and internal pterygoid muscle hypertrophy: a diagnostic challenge.

    PubMed

    Andreadis, Dimitrios; Stylianou, Florentia; Link-Tsatsouli, Iris; Markopoulos, Anastasios

    2014-01-01

    To describe an unusual case of bilateral masseter and pterygoid muscle hypertrophy. A 53-year-old female patient presented with a bilateral, painless swelling at the parotid areas without improvement after using antibiotics/systemic corticosteroids/nonsteroidal anti-inflammatory agents. Her medical history included thyroid nodules, but no dental/occlusal disorders were observed. The initial differential diagnosis included salivary gland/jaw bone/masseter pathology, but the CT/MRI revealed only an increase in the size of the masseter and pterygoid muscles. The patient was informed of the benign nature of the swelling and was advised to discontinue the use of nonsteroidal anti-inflammatory agents. The bilateral hypertrophy of masseter muscles should be considered in differential diagnosis in cases of unilateral or bilateral swelling of the parotid or lateral mandible area. © 2013 S. Karger AG, Basel.

  9. Characterization of the nociceptive effect of carrageenan: Masseter versus gastrocnemius.

    PubMed

    Bagüés, Ana; Martín-Fontelles, M Isabel; Esteban-Hernández, Jesús; Sánchez-Robles, Eva M

    2017-10-01

    To better understand the pathophysiology of chronic muscle pain, there are multiple animal models that mimic different acute/chronic pain conditions, such as carrageenan injection. Our previous studies demonstrated differences between muscles of different innervation in acute pain. In this study we characterized the effect of carrageenan in 2 muscles: masseter (trigeminal innervation) and gastrocnemius (spinal innervation). Carrageenan (3%, 6%, and 9%) was injected into the masseter and gastrocnemius of rats. Mechanical, heat, and chemical nociceptive thresholds were measured for 14 days. Carrageenan did not induce mechanical allodynia or thermal hypersensitivity in either muscle. Instead, it induced a short-lasting mechanical hyperalgesia, greater in the masseter than in the gastrocnemius. Carrageenan injected into the masseter and gastrocnemius induces a short-lasting hyperalgesia. These results could indicate a higher susceptibility of orofacial muscles to this type of insult and, consequently, a difference between trigeminal and spinal innervation. Muscle Nerve 56: 804-813, 2017. © 2016 Wiley Periodicals, Inc.

  10. The effects of masseter muscle pain on biting performance.

    PubMed

    Shiau, Y Y; Peng, C C; Wen, S C; Lin, L D; Wang, J S; Lou, K L

    2003-10-01

    The present study applied a standardized test food of known hardness to evaluate the biting performance of 20 female patients who had pain mainly in the masseter muscle during palpation. Another 20 women of a similar age group who were pain-free during examination served as controls. Electromyograms (EMG) of the masseter and sternocleidomastoid (SCM) muscles and the jaw position were recorded and measured when the subjects were biting through two types of test foods with known hardness (hard type, 20 kg hardness and extra-hard type, 60 kg hardness). Pressure-pain-threshold (PPT) values of both the patients and the normal subjects were obtained with an algometer. It was found that the PPT of the patients with pain was significantly lower and that the extra-hard food took more masseter muscle activity and more working side jaw movement in both the pain and the normal groups. During both hard and extra-hard food biting, a significantly longer duration of masseter muscle activity was found in pain patients while the total muscle activity was not significantly stronger. Strong correlation existed between SCM and masseter muscle activity during both hard and extra-hard food biting in the patient group, while such correlation was very weak in the normal group. In conclusion, painful masseter muscles required longer masseter and SCM muscle contraction time for breaking through a hard food of 20 kg and more, and co-activation of SCM and masseter muscles existed and was more evident when the food was harder or the pain was more severe.

  11. Localized eosinophilic myositis of the masseter muscle associated with actinomycosis.

    PubMed

    Aufdemorte, T B; Huntington, H W; Ripley, J F; Ramzy, I

    1983-03-01

    A case of eosinophilic myositis of the masseter associated with pseudotumor and trismus is presented. Extensive eosinophilic infiltrates of the masseter are rarely observed in the absence of parasitic infection or the hypereosinophilic syndrome. This case is reported because of the rarity of the phenomenon and its importance to the surgeon from the standpoint of differential diagnosis and treatment. The pathogenesis of the condition and its relation to other lesions of muscle associated with eosinophilic infiltration are discussed.

  12. Screening for variations in anterior digastric musculature prior to correction of post-traumatic anterior open bite by injection of botulinum toxin type A: a technical note.

    PubMed

    Zdilla, Matthew J

    2015-06-01

    It has recently been reported that long-standing post-traumatic open bite can be successfully corrected with botulinum toxin type A (BTX-A) injection into the anterior belly of the digastric muscle (ABDM). The report documented an individual with bilaterally symmetrical and otherwise unremarkable anterior digastric musculature. However, the existence of variant anterior digastric musculature is common and may complicate the management of anterior open bite with BTX-A injection. Screening for variant ABDM can be accomplished via ultrasound, computed tomography, and magnetic resonance imaging. Screening for variant ABDM should be performed prior to BTX-A injection in order to account for musculature that may exert undesired forces, such as inferolateral deviation, on the anterior mandible in patients with anterior open bite.

  13. Masseter reflex potentials in olivo-ponto-cerebellar atrophy.

    PubMed

    Imai, T; Matsumoto, H; Ohmoto, H; Chiba, S; Kobayashi, N

    1998-01-01

    We recorded masseter reflex potentials to examine the correlation between the masseter reflex and the muscle stretch reflexes of limbs in 19 patients with olivo-ponto-cerebellar atrophy (OPCA). The patients were subdivided into hyper- (n = 5), normo- (n = 7) and hypo- (n = 7) reflexia groups according to the degrees of the conventional deep tendon jerks in the upper limbs. The masseter reflex potentials, elicited by tapping the chin with a reflex hammer, were recorded from the bilateral masseters using a pair of surface electrodes. The latency of the potentials in the hyporeflexia was significantly longer than in the other groups, while the amplitude of those in the hyperreflexia group was significantly higher than in the other groups. These results indicate that in patients with OPCA the magnitude and latency of the masseter reflex correlates with the status of the muscle stretch reflexes of the limbs in contrast with Friedreich's ataxia where the masseter reflex has been reported to be normal or hyperactive despite hyporeflexia in the limbs.

  14. Facial reanimation using the masseter-to-facial nerve transfer.

    PubMed

    Klebuc, Michael J A

    2011-05-01

    This article describes facial reanimation using the transfer of the trigeminal motor nerve branch of the masseter muscle (masseter nerve) to the facial nerve (masseter-to-facial nerve transfer). A retrospective review was performed of 10 consecutive facial paralysis patients treated with a masseter-to-facial nerve transfer for reanimation of the midface and perioral region over a 7-year period. Patients were evaluated with physical examination, direct measurement of commissure excursion, and video analysis. All patients regained oral competence, good resting tone, and a smile, with a vector and strength comparable to those of the normal side. Motion developed an average of 5.6 months after masseter-to-facial nerve transfer, with 40 percent of patients developing an effortless smile by postoperative month 19. The masseter-to-facial nerve transfer is an effective method for reanimation of the midface and perioral region in a select group of facial paralysis patients. The technique is advocated for its limited donor-site morbidity, avoidance of interposition nerve grafts, and potential for cerebral adaptation, producing a strong, potentially effortless smile.

  15. An Infiltrative Angioarchitectural Variant of Arteriovenous Malformation of Temporalis

    PubMed Central

    Byatnal, Aditi Amit; Rakheja, Mahima; Byatnal, Amit Raghavendra; Narayanaswamy, Venkadasalapathy

    2014-01-01

    Vascular anomalies of the head and neck region pose a certain diagnostic and therapeutic paradox. Management of arteriovenous malformations (AVM) is a challenge owing to the presence of abnormal vascular communications and high recurrence. We report a case of a 19-year-old male patient, who presented with diffuse swelling in the right temporal region. Magnetic Resonance Angiography (MRA) suggested it to be an AVM in the temporalis muscle, having afferents in the ascending pharyngeal artery, with cavernous angioma. Surgical excision of the lesion was carried out under carotid control. Histopathology of the excised specimen utilizing special stains confirmed the presence of AVM. An absence of distinct nidus concomitant along with the exuberant proliferation of capillaries between the muscle fibres suggested it be an infiltrative angioarchitectural variant. The present case highlights significance of diagnosing AVM in temporalis muscle which is a rare occurrence in head and neck region. Also, the importance of ruling out other closely resembling vascular diathesis, both non neoplastic and malignant is discussed. PMID:25386534

  16. The role of temporalis fascia for free mucosal graft survival in small nasal septal perforation repair.

    PubMed

    Jeon, Eun-Ju; Choi, Jin; Lee, Joo-Hyung; Kim, Sung-Won; Nam, In-Chul; Park, Yong-Su; Jin, Sang-Gyun; Cheon, Byung-Jun

    2014-01-01

    Temporalis fascia has been used widely as a interposition graft for mucosal rotation flap in nasal septal perforation repair. However, the exact role of temporalis fascia in healing process has not yet been clarified. For the pedicle of rotation flap has been considered as a major vehicle for nutrition distribution, the role of temporalis fascia has been devaluated. In this study, we experienced small nasal septal perforation repairs using free mucosal graft not having pedicles but covered by temporalis fascia. Three patients with small nasal septal perforations not larger than 1 × 1 cm were included. In 2 patients, the perforations were repaired using free composite grafts from the inferior turbinate mucosa covered by continuous temporalis fascia not divided, and the surgical results were successful with complete healings. In 1 patient, however, the temporalis fascia was divided into 2 parts to better fit the shape of the perforation, and the graft failed to survive. These surgical results suggest that the temporalis fascia might have an important role in healing process of nasal septal defect and could be used as a beneficial options for small mucosal defect repair surgeries using free mucosal grafts.

  17. Effect of Reflection of Temporalis Muscle During Cranioplasty With Titanium Mesh After Standard Trauma Craniectomy.

    PubMed

    Jin, Yichao; Jiang, Jiyao; Zhang, Xiaohua

    2016-01-01

    Cranioplasty (CP) with titanium mesh after standard trauma craniectomy (STC) has been proven to be a favorable technology. According to reflection of temporalis muscle or not, the CP was divided into 2 operation ways. Effect of reflection of temporalis muscle has not been systematically researched. Thirty-nine patients were enrolled to assess the effect of reflection of temporalis muscle during CP after STC. Cranial index of symmetry was adopted to evaluate the aesthetic results, transcranial Doppler was used to assess change of cerebral blood flow (CBF), functional independence measurements were performed to monitor the improvement of neuronal function, and complications associated with CP were also recorded. The results displayed that reflection of temporalis muscle or not had no effect on the anesthetic results. Both operation ways could improve CBF and neuronal function. Cranioplasty with reflection of temporalis muscle could improve CBF and neuronal function more significantly. Furthermore, reflection of temporalis muscle would not increase complications associated with CP. Reflection of temporalis muscle during CP with titanium mesh after STC proves to be an effective and safe operation way.

  18. Lengthening Temporalis Myoplasty for Single-Stage Smile Reconstruction in Children with Facial Paralysis.

    PubMed

    Panossian, Andre

    2016-04-01

    Free muscle transfer for dynamic smile reanimation in facial paralysis is not always predictable with regard to cosmesis. Hospital stays range from 5 to 7 days. Prolonged operative times, longer hospital stays, and excessive cheek bulk are associated with free flap options. Lengthening temporalis myoplasty offers single-stage smile reanimation with theoretical advantages over free tissue transfer. From 2012 to 2014, 18 lengthening temporalis myoplasties were performed in 14 children for smile reconstruction. A retrospective chart review was completed for demographics, operative times, length of hospital stay, and perioperative complications. Fourteen consecutive patients with complete facial paralysis were included. Four patients underwent single-stage bilateral reconstruction, and 10 underwent unilateral procedures. Diagnoses included Möbius syndrome (n = 5), posterior cranial fossa tumors (n = 4), posttraumatic (n = 2), hemifacial microsomia (n = 1), and idiopathic (n = 2). Average patient age was 10.1 years. Average operative time was 410 minutes (499 minutes for bilateral lengthening temporalis myoplasty and 373 for unilateral lengthening temporalis myoplasty). Average length of stay was 3.3 days (4.75 days for bilateral lengthening temporalis myoplasty and 2.8 for unilateral lengthening temporalis myoplasty). Nine patients required minor revisions. Lengthening temporalis myoplasty is a safe alternative to free tissue transfer for dynamic smile reconstruction in children with facial paralysis. Limited donor-site morbidity, shorter operative times, and shorter hospital stays are some benefits over free flap options. However, revisions are required frequently secondary to tendon avulsions and adhesions. Therapeutic, IV.

  19. Mini-temporalis transfer as an adjunct procedure for smile restoration.

    PubMed

    Terzis, Julia K; Olivares, Fatima S

    2009-02-01

    The versatility of the temporalis muscle justifies its wide popularity in reconstructive craniomaxillofacial surgery. In late facial paralysis, results of neural reconstructive techniques such as cross-facial grafting or mini-hypoglossal-to-facial nerve transfer are partial at best. In this series, the authors have used a segmental temporalis transfer, the "mini-temporalis," to augment the function attained with neural microsurgery. The aim of this present study was to present the experience of the authors' center with the use of the mini-temporalis as an adjuvant to facial nerve microsurgery for smile restoration. Data were collected from 31 patients who underwent mini-temporalis transfer for smile restoration. In all patients, the mini-temporalis was used to augment the results of neural reconstructive techniques. Opting for the mini-temporalis related to a variety of reasons, after preoperative evaluation was weighed against the advantages and disadvantages of different reconstructive strategies on individual bases. Aesthetic and functional outcomes were evaluated by a panel of five independent observers using a five-category scale ranging from poor to excellent. All patients observed a follow-up longer than 3 months. Of 31 patients, 61.3 percent achieved excellent or good results and 29 percent achieved moderate results. All patients demonstrated an increase in the observers' scores after mini-temporalis transfer in comparison with the scores granted preoperatively or after neural microsurgery. Highly motivated patients committed to postoperative motor reeducation exhibited the best results. The clinical data presented support the use of mini-temporalis transposition in association with facial nerve microsurgery as a valuable alternative to free muscle transfer in selected cases.

  20. Facial reanimation by staged, split masseter muscle transfer.

    PubMed

    Lesavoy, Malcolm A; Fan, Kenneth L; Goldberg, Andrew G; Dickinson, Brian P; Herrera, Fernando

    2014-07-01

    Facial paralysis of the lower face presents severe functional and aesthetic disturbance to patients. The gamut of facial paralysis correction is diverse and must be tailored to the patient. When nerve repair or free functional muscle transfer is unavailable, regional muscle transfer has become a staple in surgical management of facial paralysis. Previous masseter transfers relied on orbicularis oris attachment, which may be atrophic, adhered, or lengthened. Using fascia lata grafts, we describe the senior author's method of staged, split masseter transfer as a reliable method for reanimating the lower third of the face in appropriate candidates. The staged, split masseter muscle transfer is a 3-part repair. The first stage places a hemioral fascia lata graft to act as an anchor reinforcement. The second stage transfers the split masseter muscle, suturing to the fascia lata reinforced oral commissure. The third stage, a reefing procedure, is performed 6 to 10 months later under local anesthesia to reinforce attachments. Six patients underwent the staged, split masseter muscle transfer. Mean age was 43 (15-67) years. Mean time to surgery from onset of deficit was 174 months (3 months to 65 years). All patients had significant improvement over preoperative symptoms. Symmetry was restored in repose. On movement, commissure excursion went from 0 to 6.67 mm in the superolateral vector. Of the 6 patients, 5 required an average of 1.5 outpatient revisions to achieve satisfactory results on average of 4.67 (4-127) months after the final stage. The staged, split masseter transfer is useful for restoring subtle reanimation in patients presenting with facial paralysis. The staged, split masseter transfer provides bulk and restores both static and dynamic function. We present a case series demonstrating excellent long-term functional results.

  1. Developmental and functional considerations of masseter muscle partitioning.

    PubMed

    Widmer, C G; English, A W; Morris-Wiman, J

    2007-04-01

    The masseter muscle participates in a wide variety of activities including mastication, swallowing and speech. The functional demands for accurate mandibular positioning and generation of forces during incising or a power stroke require a diverse set of forces that are determined by the innate muscle form. The complex internal tendon architecture subdivides the masseter into multiple partitions that can be further subdivided into neuromuscular compartments representing small motor unit territories. Individual masseter compartments have unique biomechanical properties that, when activated individually or in groups, can generate a wide range of sagittal and off-sagittal torques about the temporomandibular joint. The myosin heavy chain (MyHC) fibre-type distribution in the adult masseter is sexually dimorphic and is influenced by hormones such as testosterone. These testosterone-dependent changes cause a phenotype switch from slower to faster fibre-types in the male. The development of the complex organization of the masseter muscle, the MyHC fibre-type message and protein expression, and the formation of endplates appear to be pre-programmed and not under control of the muscle nerve. However, secondary myotube generation and endplate maturation are nerve dependent. The delayed development of the masseter muscle compared with the facial, tongue and jaw-opening muscles may be related to the delayed functional requirements for chewing. In summary, masseter muscle form is pre-programmed prior to birth while muscle fibre contractile characteristics are refined postnatally in response to functional requirements. The motor control mechanisms that are required to coordinate the activation of discrete functional elements of this muscle remain to be determined.

  2. Peripheral primitive neuroectodermal tumor in masseter muscle.

    PubMed

    Yazc, Haşmet; Yiğit, Barş; Doğan, Sedat; Sunter, Ahmet Volkan; Behzatoğlu, Kemal

    2013-05-01

    Primitive neuroectodermal tumor is a member of malignant small round cell tumors. These tumors especially originate from the central and autonomous nervous system. However, these tumors may be originated from peripheral tissues and are called peripheral primitive neuroectodermal tumor. A 14-year-old girl attended to the Ear Nose Throat Clinic with the complaint of progressive painless swelling mass for 2 months on the right side of the face. Neck magnetic resonance imaging showed 3.5 × 2.5 × 2-cm isointense mass on T1 and hyperintense on T2 sequences. There was no pathological lymphadenopathy on computed tomographic scan. As a result of mandibular cortical invasion seen on computed tomographic scan, radical surgical excision was decided as surgical treatment. Total parotidectomy with preserving facial nerve and partial mandibulectomy with a 2-cm margin of safety were done, and reconstruction plaque applied to the mandible. Two lymph nodes were seen at the submandibular region. For this reason, prophylactic supraomohyoid neck dissection had also been performed. Pathological assessment proved the diagnosis of PNET, and chemoradiotherapy was planned for the patient.To our knowledge, this is the second reported case in literature. In this present case, peripheral neuroectodermal tumor in the masseter muscle and its diagnosis and treatment process were reported with literature review.

  3. Modification of the Labbé Procedure: Integration of the Deep Temporalis Fascia Turnover Flap.

    PubMed

    Teven, Chad M; Bank, Jonathan; Gottlieb, Lawrence J; Reid, Russell R

    2015-06-01

    Modification of the lengthening temporalis myoplasty for reanimation of facial paralysis is presented. A patient experienced traumatic laceration of the left facial nerve resulting in left hemifacial paralysis. Multiple attempts at nerve repair were unsuccessful. For smile restoration, a Labbé procedure was performed. Because of inadequate length, the temporalis tendon could not be directly secured to the modiolus. Therefore, an inferiorly based temporalis fascia flap was recruited from the deep temporal fascia and reflected inferiorly to provide additional length by which the tendon could be secured to the modiolus. This technique provided immediate smile restoration and required no additional donor site.

  4. [Relationship between jaws and the masseter muscle by superimposing MR images on the cephalogram].

    PubMed

    Higashino, Ryoji

    2006-03-01

    The purpose of this study was to observe the morphological relationship between maxillofacial skeleton and masseter by superimposing the masseter image constructed by MR image scanning on the cephalogram. Sixteen subjects with different mandibular plane angle were examined in this study. Cephalogram and MR images of each subject were taken, and the images were input to a computer by using a digitizer. The areas of masseter were selected in each MR scan image which were projected to the mid-sagittal layer of the MR scan images. The synthesized image of cephalogram and masseter was obtained by completely superimposing sagittal images of the masseter with the mid-sagittal-plane MR image on the cephalogram. The inclination of masseter was determined by the center of gravity on the cross-section of masseter. These synthesized images of cephalogram and masseter showed various shapes of masseter according to different mandibular plane angle. The inclination of masseter had a close correlation with some skeletal parameters (mandibular plane angle, ANB, Y-axis, facial angle, saddle angle) of cephalometric analysis. The volume of the masseter also had a close correlation with skeletal parameters (mandibular plane angle, gonial angle, Y-axis). These results revealed that morphometric analysis using synthesized images of cephalogram and masseter is useful, and that the inclination and the volume of masseter may have an influence on the shape of the mandibular bone and its vertical and anteroposterior development.

  5. Hypoglossal nucleus projections to the rat masseter muscle.

    PubMed

    Mameli, O; Stanzani, S; Russo, A; Pellitteri, R; Spatuzza, M; Caria, M A; Mulliri, G; De Riu, P L

    2009-08-04

    We investigated in the rat whether hypoglossal innervation extended to facial muscles other than the extrinsic musculature of the mystacial pad. Results showed that hypoglossal neurons also innervate the masseter muscle. Dil injected into the XII nucleus showed hypoglossal axons in the ipsilateral main trunk of the trigeminal nerve. After Gasser's ganglion crossing, the axons entered into the infraorbital division of the trigeminal nerve and targeted the extrinsic muscles of the mystacial pad. They also spread into the masseter branch of the trigeminal nerve to target the polar portions of the masseter muscle spindles. Retrograde double labelling, performed by injecting Dil into the pad and True Blue into the ipsilateral masseter muscle, showed labelled hypoglossal neurons in the medio-dorsal portion of the XII nucleus. The majority of these neurons were small (15-20 microm diameter), showed fluorescence for Dil and projected to the mystacial pad. Other medium-size neurons (25 microm diameter) were instead labelled with True Blue and projected to the masseter muscle. Finally, in the same area, other small hypoglossal neurons showed double labelling and projected to both structures. Functional hypotheses on the role of these hypoglossal projections have been discussed.

  6. Hemimaxillectomy for desmoplastic ameloblastoma with immediate temporalis flap reconstruction.

    PubMed

    Elo, Jeffrey A; Tandon, Rahul; Allen, Chad N; Murray, Matthew D

    2014-08-01

    Ameloblastoma is one of the most common odontogenic tumors encountered, occurring more frequently than all other tumors combined, if one excludes the keratocystic odontogenic tumor. These tumors can cause severe expansion of the cortical bones and gross anatomic deformities. They can affect the dentition, causing tooth mobility and displacement. Fortunately, morbidity can be minimized with recognition on routine radiographic examination. The tissue may be unilocular or multilocular and has been described as having a "soap-bubble" appearance. Nevertheless, its radiographic appearance is insufficient to make a definitive diagnosis, because other tumors have similar appearance. Although the anatomic distribution and progression of ameloblastoma remain fairly consistent, alternative manifestations follow an atypical clinical course. One such variant is the desmoplastic ameloblastoma. We present a case of maxillary desmoplastic ameloblastoma treated with hemimaxillectomy and immediate reconstruction with temporalis flap that was recurrence-free at 36 months. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Myositis ossificans traumatica of temporalis and medial pterygoid muscle

    PubMed Central

    Reddy, Shyam Prasad D; Prakash, Ajay P; Keerthi, M; Rao, Brahmaji J

    2014-01-01

    Myositis ossificans is a rare disease that is characterized by bone deposition in the muscle or soft tissues. Myositis ossificans of the masticatory muscles is an uncommon finding. The condition is benign and results in heterotopic bone formation in the muscles of mastication, usually producing limitation of opening of the jaws. It is important to know the exact cause of the limitation of opening of the jaws for successful treatment. Computed tomographic scan and panoramic radiographs along with histological findings are essential diagnostic aids for evaluating conditions such as myositis ossificans. A rare case of myositis ossificans traumatica of temporalis and medial pterygoid muscle is presented here along with the discussion of clinical, radiological and histological features. The present case emphasizes not only on the importance of considering myositis ossificans in the differential diagnosis of limitation of opening of the jaws but also on the improvement of the overall mouth opening and treatment results. PMID:25328311

  8. Myositis ossificans traumatica of temporalis and medial pterygoid muscle.

    PubMed

    Reddy, Shyam Prasad D; Prakash, Ajay P; Keerthi, M; Rao, Brahmaji J

    2014-05-01

    Myositis ossificans is a rare disease that is characterized by bone deposition in the muscle or soft tissues. Myositis ossificans of the masticatory muscles is an uncommon finding. The condition is benign and results in heterotopic bone formation in the muscles of mastication, usually producing limitation of opening of the jaws. It is important to know the exact cause of the limitation of opening of the jaws for successful treatment. Computed tomographic scan and panoramic radiographs along with histological findings are essential diagnostic aids for evaluating conditions such as myositis ossificans. A rare case of myositis ossificans traumatica of temporalis and medial pterygoid muscle is presented here along with the discussion of clinical, radiological and histological features. The present case emphasizes not only on the importance of considering myositis ossificans in the differential diagnosis of limitation of opening of the jaws but also on the improvement of the overall mouth opening and treatment results.

  9. 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

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

    2013-08-01

    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.

  10. 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

  11. Lengthening temporalis myoplasty and facial paralysis from birth.

    PubMed

    Veyssière, A; Labbé, D; Bénateau, H

    2015-03-01

    Congenital facial paralysis (FP) is present from birth. It can produce major esthetic and functional disorders. It can be from two different etiologies: developmental and acquired. There is no curative treatment for congenital FP and the aim for the plastic surgeon is to restore a smile as symmetrical and as dynamic as possible. For this, two opposite techniques can be used: muscular free flaps and locoregional flaps whose lengthening temporalis myoplasty. We report our series of 34 congenital FP patients who were operated by lengthening temporalis myoplasty (LTM). We divided the patients into three categories: acquired FP (11 cases), isolated developmental FP (13 cases), and syndromic developmental FP (10 cases). The evaluation of the smile is based on the quality of the commissural course compared to the healthy side and the spontaneity of it. In the acquired FP group, 100% obtained a spontaneous smile with a postoperative delay of 9.5 months, 12 of the 13 cases of isolated developmental FP (92.7%) after 7.3 months postoperatively, and finally, in the 10 cases of syndromic FP, nine (90%) had a spontaneous smile after 9.7 months. Muscular free flaps continue to be the gold standard for the reanimation of smile on the FP. To our knowledge, no articles comparing smile restoration using free flap and smile restoration using LTM exist. A comparison of the success rates from different studies shows that both these techniques yield good results and can be used for smile restoration in FP. This technique is faster and easier than a free flap and has a same result, which is why we consider this technique as a reference on smile reanimation in FP. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

  12. Dimensions and geometry of the temporomandibular joint and masseter muscles.

    PubMed

    Zurowski, R; Gosek, M; Aleksandrowicz, R

    1976-01-01

    The bio-engineering team presents its suggestion of a method for the measurement of the temporomandibular joint and masseter muscles in order to determine the parameters necessary for exact sciences and indispensable for unified and objective cognitive studies. Ten formalin-fixed human cadavers served for the studies. The preparations were prepared by the modified method of anatomical procedure. Linear and angular measurements of temporomandibular joint and masseter muscles were carried out with the use of the three-dimensional Cartesian system of OXYZ coordinates in relation to frontal, sagittal and horizontal planes. The physiological cross-sections of the masseter, temporal, lateral and medial pterygoid muscles were also determined. The collected data make it possible to develop a mathematical three-dimensioned model of the osseo-articulo-muscular system of the mastication organ.

  13. Distribution of periodontal afferent input to motoneurons of human masseter.

    PubMed

    Yang, J; Türker, K S

    2001-11-01

    The distribution of the synaptic input from the periodontal mechanoreceptors onto the motoneurons of the human masseter is studied. Periodontal mechanoreceptors were activated using slowly rising force profiles of 2.5 N, which are known to induce predominantly excitatory reflex responses in the surface electromyogram (EMG) of the masseter. The reflex responses of single motor units (SMUs) were recorded to quantify the distribution of the periodontal input onto the masseter motoneurons. The relative sizes of motoneurons were estimated by comparing the peak-to-peak amplitude of the MacroRep (i.e. the representation of the SMU in the Macro EMG record). It was found that the larger SMUs had more excitatory and less inhibitory reflex responses than those of smaller size. This study demonstrates that the inputs from the periodontal mechanoreceptors, activated by slowly rising force profiles, are not distributed equally to the masseteric motoneurons. This may cause recruitment of motoneurons contrary to the size principle under some circumstances.

  14. Comparative study of sliced tragal cartilage and temporalis fascia in type I tympanoplasty.

    PubMed

    Khan, M M; Parab, S R

    2015-01-01

    To compare anatomical and audiological results using sliced tragal cartilage and temporalis fascia in type I tympanoplasty. A retrospective review was undertaken of primary tympanoplasties using sliced tragal cartilage and temporalis fascia from May 2005 to January 2008. In total, 223 ears were operated on using sliced tragal cartilage graft and 167 using temporalis fascia. Statistical analysis of the outcome data was performed. At the two-year and four-year follow ups, successful closure of the tympanic membrane was achieved in 98.20 per cent and 97.75 per cent, respectively, of the cartilage group compared with 87.42 per cent and 82.63 per cent, respectively, of the temporalis fascia group. At the four-year follow up, the average air-bone gap was 7.10 ± 3.01 dB in the cartilage group and 8.05 ± 3.22 dB in the temporalis fascia group. The overall success rate for primary cartilage tympanoplasty is higher when using sliced cartilage than with temporalis fascia grafting.

  15. Retrospective outcome analysis of temporalis muscle transfer for the treatment of paralytic lagophthalmos.

    PubMed

    Miyamoto, Shimpei; Takushima, Akihiko; Okazaki, Mutsumi; Momosawa, Akira; Asato, Hirotaka; Harii, Kiyonori

    2009-09-01

    Temporalis muscle transfer for paralytic lagophthalmos, which was first proposed by Gillies and later developed by Andersen, has been one of the most common treatment modalities for paralytic lagophthalmos. However, there have been no scientific reports statistically analysing the efficacy of temporalis muscle transfer. We, therefore, retrospectively analysed the functional and aesthetic results of temporalis muscle transfer. Between 1994 and 2006, we carried out temporalis muscle transfer (the so-called Gillies-Andersen method) on 95 established facial paralysis patients. We sent a postal questionnaire to these patients and 47 of them responded. The functional and aesthetic results were analysed based on the patients' replies together with clinical records and photographs, and unfavourable factors of this procedure were investigated. After surgery, most ocular symptoms (mechanical irritation, dry eye, soreness, and discharge) improved significantly. Achievement rate of complete eye closure was 78.7%. A morphometric study revealed that possible unfavourable factors (old age, intracranial disease, use of dentures, etc.) did not affect the achievement rates of complete eye closure. Deformity of eyelid fissure due to undue tension of the temporal fascia fixation was found in nine patients (19.1%) and six of these patients underwent secondary revision. Unlike lid loading with a gold implant, the results of temporalis muscle transfer depend greatly on the surgeon's skill. However, if this procedure is performed properly, strong eye closure can be obtained. We, therefore, recommend temporalis muscle transfer as the preferred option for reconstruction of paralytic lagophthalmos.

  16. Reconstruction of composite oral cavity defects with temporalis flaps after prior treatment.

    PubMed

    Zenga, Joseph; Nussenbaum, Brian; Rich, Jason T; Sclaroff, Allen; Diaz, Jason A

    2015-01-01

    Reconstruction of composite oral cavity defects in the setting of prior surgery and radiotherapy presents a significant challenge. Although free tissue transfer has shown success in such situations, it is not without considerable risk. Regional pedicled flaps may provide a more suitable alternative. In certain patients, however, severe soft tissue fibrosis makes more conventional regional flaps impractical or impossible. In these situations, temporalis flaps (temporalis muscle and temporoparietal fascia flaps) are versatile options for coverage of complex defects. To report our experience using pedicled temporalis flaps for reconstruction of composite oral cavity defects in patients with significant co-morbidities and prior treatment. Three patients were identified and their medical records were reviewed. Their clinical courses and functional outcomes are described. We include a discussion of the operative technique and relevant literature. All patients had previously undergone extensive treatment. One patient needed reconstruction after resection of a third head and neck malignancy and two patients presented for treatment of osteoradionecrosis. A temporalis muscle flap was used to reconstruct composite oral cavity defects in two patients and a combined temporalis muscle and temporoparietal fascia flap was used for independent defects in one patient. All flaps survived. Functional status and pain improved or stabilized in all patients. There were no major or minor complications. In previously treated fields, where more conventional flaps are impractical, temporalis flaps are a suitable alternative to achieve a stable healing wound and prevent worsening of functional status. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Management of Unilateral Masseter Hypertrophy and Hypertrophic Scar—A Case Report

    PubMed Central

    Shetty, Naresh; Malaviya, Rajanikanth K.; Gupta, M. K.

    2012-01-01

    Masseter muscle hypertrophy is a rare condition of idiopathic cause. It clinically presents as an enlargement of one or both masseter muscles. Most patients complain of facial asymmetry; however, symptoms such as trismus, protrusion, and bruxism may also occur. Several treatment options reported for masseter hypertrophy are present, which range from simple pharmacotherapy to more invasive surgical reduction. Keloid scar with unilateral masseter hypertrophy is a rarely seen in clinical practice. This paper reports a case of unilateral masseter hypertrophy with keloid scar in the angle of the mandible for which surgical treatment was rendered to the patient by using a single approach. PMID:22844620

  18. Association between facial growth pattern and facial muscle activity: A prospective cross-sectional study.

    PubMed

    Alabdullah, Mohannad; Saltaji, Humam; Abou-Hamed, Hussein; Youssef, Mohamed

    2015-06-01

    To evaluate the relationship between facial growth pattern and electromyography (EMG) of facial muscles: anterior temporalis, masseter, buccinators, orbicularis oris, mentalis and anterior digastric. The sample consisted of 77 subjects aged between 18-28 years (mean age 21.10±2.03), with dental Class I relationship, normal overjet and overbite, balanced facial profile, no signs of temporomandibular disorders, and no previous orthodontic treatment. Facial growth pattern was determined on the lateral cephalograms according to the Björk sum (sum of the N-S-Ar, S-Ar-Go, and Ar-Go-Me angles) dividing the sample into three groups: horizontal facial pattern group (24 subjects), normal facial pattern group (41 subjects), and vertical facial pattern group (12 subjects). The EMG of anterior temporalis, masseter, buccinator, orbicularis oris, mentalis and anterior digastric muscles were examined for each patient in the rest position and in functional positions (central maximum intercuspation, chewing on right side, chewing on left side and swallowing). Mean values and standard deviation of EMG were obtained and compared between the three groups. At rest, the EMG of the masseter, orbicularis oris and anterior digastric were higher in the vertical facial pattern group compared with the other two groups, with a moderate positive correlation between the EMG of these muscles and the Björk sum (P<.01). In contrast, during central maximum intercuspation, the activity of the anterior temporalis, masseter and buccinator was significantly lower in the vertical facial pattern group compared with the two other groups, with a moderate negative correlation between the Björk sum and EMG in the maximum central intercuspation position of these muscles (P<.01). A significant relationship was found between facial muscle activity and facial growth pattern. The findings suggest that the activity of masticatory and perioral muscles could play a role in the direction of the facial growth

  19. [Benefits and limits of sonography of the masseter muscle].

    PubMed

    Siegert, R; Wimmer, L

    1990-07-01

    A sonographic method for diagnosis, follow-up and quantification of normal and hypertrophied masseter muscles is presented. This technique lends itself to diagnosis of macroscopic structural alterations of the muscle as well as tumors in the vicinity. Functional or microscopic tissue changes like trigger points in myofacial pain-dysfunction syndrome cannot be detected sonographically.

  20. 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.

  1. Relationship between masseter muscle size and maxillary morphology.

    PubMed

    Uchida, Yasuki; Motoyoshi, Mitsuru; Shigeeda, Toru; Shinohara, Akihiko; Igarashi, Yu; Sakaguchi, Masahito; Shimizu, Noriyoshi

    2011-12-01

    The aim of this study was to investigate the relationship between masseter muscle size and craniofacial morphology, focusing on the maxilla. Twenty-four patients (11 males and 13 females; mean age 27.6 ± 5.6 years) underwent cephalometric analyses. Ultrasonography was used to measure the cross-sectional area (CSA) of the masseter muscle and bite force was measured using pressure sensitive film. The results showed that CSA-relaxed was positively correlated with upper anterior face height (UAFH)/total anterior face height (TAFH) and negatively with lower anterior face height (LAFH)/TAFH and LAFH (P < 0.05). CSA-clenched was correlated positively with SN-palatal, FH-palatal, UAFH/TAFH, and lower posterior face height (LPFH)/total posterior face height (TPFH) and negatively with LAFH/TAFH, LAFH, upper posterior face height (UPFH)/TPFH, and UPFH (P < 0.05). Bite force was positively correlated with LPFH/TPFH and negatively with UPFH/TPFH (P < 0.05). As the masseter became larger, the anterior maxillary region tended to shift downwards relative to the cranial base, whereas the posterior region tended to shift upwards. The decrease in LAFH/TAFH and increase in LPFH/TPFH as the size of the masseter muscle increases may be influenced not only by the inclination of the mandibular plane but also by the clockwise rotation of the maxilla.

  2. Comparative studies of the venom of a new Taipan species, Oxyuranus temporalis, with other members of its genus.

    PubMed

    Barber, Carmel M; Madaras, Frank; Turnbull, Richard K; Morley, Terry; Dunstan, Nathan; Allen, Luke; Kuchel, Tim; Mirtschin, Peter; Hodgson, Wayne C

    2014-07-02

    Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified "profile" compared to other taipan venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans.

  3. Comparative Studies of the Venom of a New Taipan Species, Oxyuranus temporalis, with Other Members of Its Genus

    PubMed Central

    Barber, Carmel M.; Madaras, Frank; Turnbull, Richard K.; Morley, Terry; Dunstan, Nathan; Allen, Luke; Kuchel, Tim; Mirtschin, Peter; Hodgson, Wayne C.

    2014-01-01

    Taipans are highly venomous Australo-Papuan elapids. A new species of taipan, the Western Desert Taipan (Oxyuranus temporalis), has been discovered with two specimens housed in captivity at the Adelaide Zoo. This study is the first investigation of O. temporalis venom and seeks to characterise and compare the neurotoxicity, lethality and biochemical properties of O. temporalis venom with other taipan venoms. Analysis of O. temporalis venom using size-exclusion and reverse-phase HPLC indicated a markedly simplified “profile” compared to other taipan venoms. SDS-PAGE and agarose gel electrophoresis analysis also indicated a relatively simple composition. Murine LD50 studies showed that O. temporalis venom is less lethal than O. microlepidotus venom. Venoms were tested in vitro, using the chick biventer cervicis nerve-muscle preparation. Based on t90 values, O. temporalis venom is highly neurotoxic abolishing indirect twitches far more rapidly than other taipan venoms. O. temporalis venom also abolished responses to exogenous acetylcholine and carbachol, indicating the presence of postsynaptic neurotoxins. Prior administration of CSL Taipan antivenom (CSL Limited) neutralised the inhibitory effects of all taipan venoms. The results of this study suggest that the venom of the O. temporalis is highly neurotoxic in vitro and may contain procoagulant toxins, making this snake potentially dangerous to humans. PMID:24992081

  4. Impact of the nature of the temporalis fascia graft on the outcome of type I underlay tympanoplasty.

    PubMed

    Jiang, Z; Lou, Z

    2017-06-01

    Temporalis fascia has become the most widely used graft for tympanoplasty, as it is strong, durable, and easy to procure and handle. However, the type of temporalis fascia graft to use (i.e. dry or wet) remains controversial. The present review aimed to evaluate the success rates of dry and wet temporalis fascia grafts in type I underlay tympanoplasty. A literature search was performed, using PubMed up to August 2016, to identify all studies of dry and wet temporalis fascia grafts in type I underlay tympanoplasty. The initial search using the key words 'temporalis fascia' and 'tympanoplasty' identified 130 articles; these were screened by reviewing the titles or abstracts based on the inclusion and exclusion criteria. Ultimately, this review included seven articles. A dry or wet temporalis fascia graft did not affect the outcome of type I underlay tympanoplasty. However, using wet temporalis fascia could shorten the duration of surgery in type I underlay tympanoplasty. Concerns that the fibroblast count of temporalis fascia may beneficially affect success rate have not been substantiated in clinical reports thus far.

  5. The course of the buccal nerve: relationships with the temporalis muscle during the prenatal period

    PubMed Central

    MÉRIDA-VELASCO, J. R.; RODRÍGUEZ-VÁZQUEZ, J. F.; CUADRA, C.; MÉRIDA-VELASCO, J. A.; JIMÉNEZ-COLLADO, J.

    2001-01-01

    The aim of this study was to describe the course of the buccal nerve and its relationships with the temporalis muscle during the prenatal period. Serial sections of 90 human fetal specimens ranging from 9 to 17 wk development were studied by light microscopy. Each fetal specimen was studied on both right and left sides, making a total of 180 cases for study. A 3-D reconstruction of the region analysed in one of the specimens was made. In 89 cases the buccal nerve was located medial to the temporalis muscle; in 73 cases it penetrated the muscle; in 15 cases it lay in a canal formed by the muscle fibres and was covered by fascia, and finally, in 3 cases it was a branch of the inferior alveolar nerve. The study has revealed that in a large number of cases the buccal nerve maintains an intimate association with the temporalis muscle. PMID:11327204

  6. Acoustic myography, electromyography and bite force in the masseter muscle.

    PubMed

    Tortopidis, D; Lyons, M F; Baxendale, R H

    1998-12-01

    Acoustic myography (AMG) offers some advantages over electromyography (EMG) in certain circumstances, but the use of AMG on the jaw-closing muscles has not been fully tested. The purpose of this study was to examine the relationship between AMG, EMG and force in the masseter muscles of nine healthy male subjects. The AMG was recorded using a piezoelectric crystal microphone and the EMG was recorded simultaneously with surface electrodes. Force was recorded between the anterior teeth with a strain-gauge transducer. Analysis showed that Pearson's correlation coefficient was 0.913 for force/AMG and 0.973 for force/EMG in all subjects, indicating a linear relationship between force, AMG and EMG at the four different force levels tested (25-75% of maximum). It is apparent that AMG may be used as an accurate monitor of masseter muscle force production, although some care is required in the technique.

  7. Temporalis Muscle Tendon Unit Transfer for Smile Restoration After Facial Paralysis.

    PubMed

    Owusu Boahene, Kofi D

    2016-02-01

    Temporalis muscle tendon unit (MTU) transfer may be used as a single-stage procedure for dynamic reanimation of the paralyzed face. Principles and biomechanics of muscle function and tendon transposition are essential in optimizing outcome. Critical steps and pearls for success include minimizing scarring, maintaining glide plains, mobilizing adequate tendon length, insertion of MTU at ideal tension based on intraoperative dynamic tension-excursion relationship, and insertion of tendon as close to the lip margin as possible. Because muscles adapt to tension, load, and task changes by altering their sarcomere arrangement and muscle fiber composition, physiotherapy should be initiated to use the repurposed temporalis MTU for smile restoration.

  8. Ultrasound measurements of the masseter muscle as predictors of cephalometric indices in orthodontics: a pilot study.

    PubMed

    Naser-Ud-Din, S; Sampson, W J; Dreyer, C W; Thoirs, K

    2010-09-01

    This study investigated the potential of ultrasound measurements of the masseter muscle to accurately predict indices normally derived from cephalograms. Masseter muscle measurements on 11 adults (22 to 30 y) were made using lateral cephalometrics and extended field-of-view ultrasound. The ultrasound technique was validated in a simulation pilot study using 12 dry skulls and raw chicken breasts. Twenty cephalometric variables were analyzed against four ultrasound measurements of the masseter muscle. Highly significant correlations (r = 0.81-0.85, p = 0.001-0.002) between ultrasound measurements of the masseter muscle and cephalometric measurements representing the length of the superficial masseter muscle, the length and shape of the mandible and vertical facial proportions were demonstrated. Predictive equations from regression analyses were constructed to deduce ramus length and shape from the ultrasound measurements. The results provide pilot data suggesting that ultrasound is a potential clinical tool for sequential evaluation of masseter muscle length in orthodontics and facial muscle growth studies.

  9. 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

  10. Diverse firing properties of single motor units in the inner and outer portions of the guinea pig anterior digastric muscle.

    PubMed

    Lev-Tov, A; Tal, M; Lavy, R

    1993-02-01

    Microwire recordings from the histochemically heterogeneous inner compartment of the guinea pig anterior digastric muscle (ADG) revealed tonic firing of single motor units, which were spontaneously active and could also be recruited following orofacial afferent stimulation and during rhythmic jaw movements (RJM). As units with tonic firing were not observed in the homogeneously fast-twitch outer ADG, the tonic units were classified as slow-twitch motor units. Irregular patterns of motor-unit firing at variable frequencies were observed after orofacial stimulation and during RJM in the outer and inner compartments. The irregular firing pattern of units in the fast-twitch outer compartment was characterized by shorter and less variable bursts than that of units in the heterogeneous inner compartment. A phasic, centrally driven firing pattern was observed during RJM in outer and inner ADG units. The firing frequency of some of these units was modulated during the rhythmical bursts. It is suggested that, as in limb muscles, functionally specialized ADG motor units are recruited in an orderly sequence, starting with spontaneously active, slow-twitch units in the inner compartment, continuing with fast-twitch units recruited upon enhancement of the synaptic drive (as in the case of orofacial stimulation), and ending with massive, rhythmical recruitment of slow- and fast-twitch units during RJM.

  11. Recruitment stability in masseter motor units during isometric voluntary contractions.

    PubMed

    Scutter, S D; Türker, K S

    1998-10-01

    Recruitment of single motor units (SMUs) of the masseter muscle was studied using macro representation (MacroRep) as the indicator of motor unit size. When subjects followed a slow isometric force ramp, units were usually recruited in order of MacroRep size. However, pooling the data from repeated ramps in the same subject resulted in a weak relationship between MacroRep size and force recruitment threshold, probably due to marked variations in the relative contributions of the jaw muscles, and varying levels of cocontraction, in the development of total bite force in each ramp. The force recruitment thresholds of individual SMUs showed marked variability, but recruitment threshold stability was improved when expressed as a percentage of maximum surface electromyographic (SEMG) activity in the ipsilateral masseter. Therefore the SEMG recruitment threshold was concluded to be a more stable and accurate indicator of the SMU's position in the recruitment hierarchy in a given muscle. It was concluded that SMUs in masseter are recruited according to the size principle, and that when investigating recruitment in jaw muscles, SEMG recruitment threshold should be used in preference to force recruitment threshold.

  12. Simultaneous Bilateral Hypertrophies of the Parotid Gland and Masseter Muscle: Case Report.

    PubMed

    Prabhu, Rohan; Mandel, Louis

    2017-01-01

    Increased salivary demand can lead to enlarged parotid salivary glands, and increased activity of the masseter muscles can cause masseter hypertrophy. This report describes a most unusual case of simultaneous bilateral hypertrophies of the parotid gland and masseter muscle originating from the very extensive habit of chewing gum. An extensive literature review uncovered many cases of the independent existence of masseteric or parotid hypertrophy, but no example of the simultaneous occurrence of these 2 conditions.

  13. Prolonging the duration of masseter muscle reduction by adjusting the masticatory movements after the treatment of masseter muscle hypertrophy with botulinum toxin type a injection.

    PubMed

    Wei, Jiao; Xu, Hua; Dong, Jiasheng; Li, Qingfeng; Dai, Chuanchang

    2015-01-01

    Botulinum toxin type A (BTX-A) is widely used for the clinical treatment of masseteric hypertrophy. Until now, few reports have discussed how to prolong the duration of its effectiveness. This study evaluated that purposely adjusting the masticatory movements is possible of postponing the masseter muscle rehypertrophy. Ninety-eight patients were randomly and equally divided into 2 groups, and 35 U BTX-A per side was injected into the masseters. The thickness and volume of the masticatory muscles were measured by ultrasound and computerized tomography, respectively. Patients in Group 1 were instructed to strengthen their masticatory effort during the denervated atrophic stage of the masseter (the interval was evaluated by real-time ultrasound monitoring), whereas patients in Group 2 were not given this instruction. When the masseter muscle began to recover, patients in both groups were instructed to reduce their chewing. The duration of the masseter muscle rehypertrophy was significantly prolonged in Group 1 patients. The thickness and the volume of the other masticatory muscles were significantly increased in Group 1 but were either slightly decreased or insignificantly different in Group 2. Purposely strengthening masticatory muscle movement during the denervated atrophic stage of the masseter can prolong the duration of masseter rehypertrophy.

  14. Endoscopic Transmaxillary Transposition of Temporalis Flap for Recurrent Cerebrospinal Fluid Leak Closure.

    PubMed

    Thomas, Regi; Girishan, Shabari; Chacko, Ari George

    2016-12-01

    Objective To describe the technique of endoscopic transmaxillary temporalis muscle flap transposition for the repair of a persistent postoperative sphenoidal cerebrospinal fluid leak. Design The repair of a recurrent cerebrospinal fluid leak for a patient who had undergone endoscopic transsphenoidal excision of an invasive silent corticotroph Hardy C and Knosp Grade IV pituitary adenoma was undertaken. The patient had completed postoperative radiotherapy for the residual tumor and presented with cerebrospinal fluid leak, 1 year later. The initial two attempts to repair the cerebrospinal fluid leak with free grafts failed. Therefore, an endoscopic transmaxillary transposition of the temporalis muscle flap was attempted to stop the cerebrospinal fluid leak. Results The endoscopic transmaxillary transposition of the vascularized temporalis muscle flap onto the cerebrospinal fluid leak repair site resulted in successful closure of the cerebrospinal fluid leak. Conclusion Endoscopic transmaxillary transposition of the temporalis flap resulted in closure of recurrent cerebrospinal fluid leak in a patient with recurrent pituitary adenoma, who had undergone previous surgery and radiotherapy. This technique has advantages over the endoscopic transpterygoid transposition of the same flap and could be used as a complementary technique in selected patients.

  15. Autologous Vascularized Dural Wrapping for Temporalis Muscle Preservation and Reconstruction After Decompressive Craniectomy: Report of Twenty-five Cases

    PubMed Central

    Di Rienzo, Alessandro; Iacoangeli, Maurizio; Alvaro, Lorenzo; Colasanti, Roberto; Nocchi, Niccolo; Di Somma, Lucia Giovanna Maria; Scerrati, Massimo

    2013-01-01

    Temporalis muscle reconstruction is a necessary step during frontotemporal cranioplasty ensuing decompressive craniectomy (DC). During this procedure, scarring between the temporalis muscle and the dural layer may lead to complicated muscle dissection, which carries an increased risk of dura and muscle damage. At time of DC, temporalis muscle wrapping by an autologous vascularized dural flap can later on facilitate dissection and rebuilding during the subsequent cranioplasty. In a span of 2 years, we performed 57 DCs for different etiologies. In 30 cases, the temporalis muscle was isolated by wrapping its inner surface using the autologous dura. At cranioplasty, the muscle could easily be dissected from the duraplasty. The inner surface was easily freed from the autologous dural envelope, and reconstruction achieved in an almost physiological position. Follow-up examinations were held at regular intervals to disclose signs of temporalis muscle depletion. Twenty-five patients survived to undergo cranioplasty. Muscle dissection could always be performed with no injury to the dural layer. No complications related to temporalis muscle wrapping were recorded. Face asymmetry developed in four cases but it was always with bone resorption. None of the patients with a good neurological recovery reported functional or aesthetic complaints. In our experience, temporalis muscle wrapping by vascularized autologous dura proved to be effective in preserving its bulk and reducing its adhesion to duraplasty, thereby improving muscle dissection and reconstruction during cranioplasty. Functional and aesthetic results were satisfying, except in cases of bone resorption. PMID:24067769

  16. The vascular anatomy of the human temporalis muscle: implications for surgical splitting techniques.

    PubMed

    Cheung, L K

    1996-12-01

    Despite the wide application of the temporalis muscle flap and its modifications, understanding of the vascular pattern and territories within the muscle remains poor. This study aimed to evaluate the vascular architecture in the human temporalis muscle for surgical application. The material comprised 15 fresh cadavers (30 muscle specimens), which were divided into three groups for vascular infusion by either Indian ink solution, lead oxide solution, or methylmethacrylate resin. The vascular network in the temporalis muscle was analyzed by stereomicroscopy, radiography, and scanning electron microscopy. The human temporalis muscle was found to have vascular supply from three primary arteries: the anterior deep temporal artery (ADTA), the posterior deep temporal artery (PDTA), and the middle temporal artery (MTA). Each primary artery branched into the secondary arterioles and then the terminal arterioles. The venous network accompanied the arteries, and double veins pairing one artery was a common finding. The capillaries formed a dense, interlacing network with orientation along the muscle fibres. Arteriovenous anastomosis was absent. In the coronal plane, the vessels were located mainly on the lateral and medial aspects of the muscle with a significantly lower vascular density in the midline. Morphometric analysis of the arterial network showed that the PDTA was larger in size at primary and secondary branching levels than the ADTA and the MTA, whereas no differences were present at the terminal arteriolar levels. The distribution of the arterial territories was as follows: the ADTA occupied 21% anteriorly, the PDTA occupied 41% in the middle region, and the MTA occupied 38% in the posterior region. This improved understanding of the vascular architecture within the temporalis muscle complements the anatomic basis of the flap-splitting technique and increases the safety of its application.

  17. Anterior temporalis and suprahyoid EMG activity during jaw clenching and tooth grinding.

    PubMed

    Aldana, Karina; Miralles, Rodolfo; Fuentes, Aler; Valenzuela, Saúl; Fresno, María Javiera; Santander, Hugo; Gutiérrez, Mario Felipe

    2011-10-01

    The aim of this study was to evaluate the anterior temporalis and suprahyoid electromyographic (EMG) activity during jaw clenching and tooth grinding at different jaw posture tasks. The study included 30 healthy subjects with natural dentition and bilateral molar support, incisive protrusive guidance and bilateral laterotrusive canine guidance. Bipolar surface electrodes were located on the right anterior temporalis and suprahyoid muscles. Three EMG recordings in the standing position were performed in the following tasks: C. clenching in the intercuspal position (IP); P1. eccentric grinding from IP to protrusive edge-to-edge contact position; P2. clenching in protrusive edge-to-edge contact position; P3. concentric grinding from protrusive edge-to-edge contact position to IP; L1. eccentric grinding from IP to laterotrusive edge-to-edge contact position; L2. clenching in laterotrusive edge-to-edge contact position; L3. concentric grinding from laterotrusive edge-to-edge contact position to IP. EMG activity during protrusive and laterotrusive tasks was lower than intercuspal position in the anterior temporalis, whereas an opposite EMG pattern was observed in the suprahyoid muscles activity, excepting recorded activity in L2 (mixed model with unstructured covariance matrix). Anterior temporalis activity was higher during P3 than P1 and P2 tasks and during L3 than L1 and L2 tasks, whereas in the suprahyoid muscles, activity was higher during P1 than P2 tasks and during L1 than L2 and L3 tasks. These results could support the idea of a differential modulation of the motor neuron pools of anterior temporalis and suprahyoid muscles of peripheral and/or central origin.

  18. Use of mini-temporalis transposition to improve free muscle outcomes for smile.

    PubMed

    Terzis, Julia K; Olivares, Fatima S

    2008-12-01

    In managing late facial paralysis, association of cross-facial nerve grafting and free muscle transfer proves superior to any other method of mid-face reanimation. Nevertheless, predicting functional recovery remains a struggle, and in a minority of patients, results are deceiving. In this study, cases of fair or moderate outcomes from a free muscle transfer received a segmental temporalis transposition to upgrade the functional and aesthetic results. From 1981 to 2007, 153 patients received a free muscle transfer for smile restoration in the authors' center. Of all patients, 72 percent (110 patients) required a third stage of revisions. In 41 cases, mini-temporalis transfer was used to augment moderate outcomes of a free muscle transfer. The exclusion criterion was less than 3 months' follow-up; thus, six patients were not evaluated. Each patient was videotaped at three successive time points (preoperatively, following free muscle transfer, and following mini-temporalis transfer). Five independent observers graded patients' videos using a five-category scale from poor to excellent. In all of the patients, the averaged scores were higher after free muscle transfer in comparison with the preoperative scores (Wilcoxon signed rank test, p < 0.0001). After mini-temporalis transfer, 97.1 percent of the patients had scores that were increased further and 2.8 percent had the same scores. Alopecia along the coronal incision was seen in four patients, and hollowing of the infratemporal fossa was seen in five. Analysis of these clinical data supports the use of mini-temporalis transfer as a safe and reliable method of correcting imperfect outcomes following a free muscle transfer for smile restoration.

  19. Elevated Fractalkine (CX3CL1) Levels in the Trigeminal Ganglion Mechanically Sensitize Temporalis Muscle Nociceptors.

    PubMed

    Cairns, Brian E; O'Brien, Melissa; Dong, Xu-Dong; Gazerani, Parisa

    2016-05-21

    It has been proposed that after nerve injury or tissue inflammation, fractalkine (CX3CL1) released from dorsal root ganglion neurons acts on satellite glial cells (SGCs) through CX3C receptor 1 (CX3CR1) to induce neuroplastic changes. The existence and importance of fractalkine/CX3CR1 signaling in the trigeminal ganglia has not yet been clarified. This study investigated (1) whether trigeminal ganglion neurons that innervate temporalis muscle and their associated SGCs contain fractalkine and/or express CX3CR1, (2) if intraganglionic injection of fractalkine increases the mechanical sensitivity of temporalis muscle afferent fibers, (3) whether complete Freund's adjuvant (CFA)-induced inflammation of the temporalis muscle alters the expression of fractalkine or its receptor in the trigeminal ganglion, and (4) if intraganglionic administration of CX3CR1 antibodies alters afferent mechanical sensitivity. Immunohistochemistry and in vivo electrophysiological recordings in male and female rats were used to address these questions. It was found that ∼50 % of temporalis ganglion neurons and ∼25 % of their associated SGCs express CX3CR1, while only neurons expressed fractalkine. Temporalis muscle inflammation increased the expression of fractalkine, but only in male rats. Intraganglionic injection of fractalkine (25 g/ml; 3 μl) induced prolonged afferent mechanical sensitization. Intraganglionic injection of CX3CR1 antibody increased afferent mechanical threshold, but this effect was greater in controls than in rats with CFA-induced muscle inflammation. These findings raise the possibility that basal fractalkine signalling within the trigeminal ganglion plays an important role in mechanical sensitivity of masticatory muscle sensory afferent fibers and that inhibition of CX3CR1 signaling within the trigeminal ganglia may induce analgesia through a peripheral mechanism.

  20. Modelling relative masseter force from surface electromyograms during mastication in non-human primates.

    PubMed

    Hylander, W L; Johnson, K R

    1993-03-01

    The purpose was to analyse the relation between masseter electromyograms (EMGs) and relative masseter force during the power stroke of mastication. The electromyographic activity of the masseter was characterized by recording from bipolar surface electrodes placed over the superficial portion of the muscle; relative masseter force was estimated by characterizing surface bone strain along the lateral aspect of the zygomatic arch. The subjects were six adult macaques and one adult baboon. Masseter EMGs were quantified by r.m.s. analysis of the raw digitized EMG. The length of the time interval (the time constant) during which the r.m.s. values were calculated was repeatedly altered so as to determine which time constant was optimal for producing an EMG-derived waveform that best mimicked relative masseter force during the near-isometric phase of muscle contraction. The data indicate that between subjects this time constant varied from 35 to 72 ms, with an overall median of 42 ms and a grand mean of 49 ms. The use of a 42-ms time constant for all of the subjects resulted in an average latency between the masseter EMG waveform and relative masseter force of about 30 ms during the latter portion of the power stroke of mastication. This analysis provides, as a first approximation, an empirical basis for modelling relative jaw-muscle force using surface EMGs recorded during that portion of the power stroke of mastication when the jaw-closing muscles are contracting under near isometric conditions.

  1. Functional compartmentalization of the human superficial masseter muscle.

    PubMed

    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).

  2. 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

  3. Anatomical relationship between the position of the sigmoid sinus, tympanic membrane and digastric ridge with the mastoid segment of the facial nerve.

    PubMed

    Boemo, R L; Navarrete, M L; Lareo, S; Pumarola, F; Chamizo, J; Perelló, E

    2008-04-01

    Our study was carried out to examine the relationships of the sigmoid sinus, tympanic membrane and digastric ridge with the mastoid segment of the facial nerve. We studied 33 adult temporal bones. The distances among these structures were evaluated according specific landmarks that can be repeated in a simple manner. We found a good relation, in a proportional and lineal order, between these three structures and the facial nerve. This study indicated a correlation between the position of these three structures and the mastoid segment of the facial nerve through a simple morphometric method.

  4. 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

  5. Assessment of functional outcomes of temporalis muscle transfers for patients with longstanding facial paralysis.

    PubMed

    Scaglioni, Mario F; Verdini, Federica; Marchesini, Andrea; Neuendorf, Alexander Dietrich; Coccia, Daniele; Leo, Tommaso; Riccio, Michele

    2016-04-01

    Usually, clinical evaluation of facial reanimation provides accurate information about contraction of the mimetic muscles and phonation but fails to identify smile recovery and to quantify the motility of the lower third of the face during a smile. The purpose of this study was to verify that, in longstanding facial palsy, the modified temporalis muscle transfer (MTMT) can result in the ability to smile, not only voluntarily with chewing, but also spontaneously with a sudden emotional stimulus, and to confirm that a symmetric smile can be obtained. Ten patients of the treated group (group T; 4 women and 6 men) were randomly selected from a population of 24 patients with longstanding facial palsy treated by MTMT. Five normal subjects of the control group (group C; 3 women and 2 men) were enrolled as the control population. Functional outcomes after transposed temporalis muscle were examined and measured through clinical assessment by using a scored smile symmetry grading system, video recording, and surface electromyography (sEMG). In addition, the voluntary smile test (VST) and the not-voluntary smile test (NVST) were performed to study voluntary and spontaneous smiling. Subjects in the VST group (group T) were able to smile voluntarily and the expression was characterized by symmetry. In the NVST group, they were able to smile spontaneously and the symmetry of the smile was maintained for 8 subjects and only partially for 2 subjects. During both tests, the temporalis muscle of the treated side and the orbicularis oris muscle of the not-treated side were activated during smiling, indicating spontaneous activity of the transposed temporalis muscle with an emotional stimulus. For the control group, smiles during VST and NVST were symmetric and the temporalis muscles were not activated during smiling, whereas the orbicularis oris muscles were. Our study shows that the Morrison MTMT is able to restore the voluntary smile ability. Particularly, this technique allows for

  6. Medullary infarcts may cause ipsilateral masseter reflex abnormalities.

    PubMed

    Thömke, Frank; Marx, Jürgen J; Cruccu, Giorgio; Stoeter, Peter; Hopf, Hanns C

    2007-10-01

    There is a suprasegmental influence on the masseter reflex (MassR) in animals, which is mediated via the fifth nerve spinal nucleus (5SpN). Corresponding data in humans are lacking. Out of 268 prospectively recruited patients with clinical signs of acute brainstem infarctions, we identified 38 with magnetic resonance imaging (MRI)-documented unilateral infarcts caudal to the levels of the fifth nerve motor and main sensory nuclei. All had biplanar T2- and echo planar diffusion-weighted MRI and MassR testing. Five patients (13%) had ipsilateral MassR abnormalities. In all, the infarcts involved the region of the 5SpN. Patients with medullary infarcts involving the region of the 5SpN may thus have ipsilateral MassR abnormalities. This possibly represents an interruption of an excitatory projection mediated via the 5SpN to masseter motoneurons in the fifth nerve motor nucleus. MassR abnormalities with medullary lesions restrict the topodiagnostic value of the MassR.

  7. Suspension of the tongue to the digastric tendon following resection of the anterior mandibular arch for oral cancer prevents postoperative tongue fall and avoids the need for tracheostomy.

    PubMed

    Pandey, D

    2012-01-01

    Resection of the anterior arch of the mandible leads to tongue fall and postoperative stridor because of the detachment of tongue musculature from the mandible. In this article, a simple method of tongue suspension is described which would prevent such complications and the need for tracheostomy. This study was carried out on patients with oral cancer requiring resection of the anterior arch of the mandible as a part of the surgical resection at a tertiary centre. This study was performed on 32 patients with oral cancer requiring resection of the anterior arch of the mandible as a part of the surgical resection. Following an appropriate resection of the oral cancer (including the anterior mandibular arch) and neck dissection, a silk suture is used to loop the tongue musculature on either side to the intermediate tendon of the digastric muscle. This technique of tongue suspension was used in 32 patients who required resection of the anterior mandibular arch for oral cancer. Prophylactic tracheostomy was not performed. One patient developed stridor at extubation and required temporary tracheostomy. All other patients could be successfully extubated within 12 h of surgery and none experienced postoperative stridor or sleep apnea. One other patient required temporary tracheostomy for pulmonary toilet as he developed aspiration pneumonitis related to nasogastric feed. This simple method of tongue suspension to the digastric tendon prevents postoperative tongue fall and obviates the need for tracheostomy in most instances.

  8. Task-dependence of jaw elevator and depressor co-activation.

    PubMed

    Proeschel, P A; Raum, J

    2003-08-01

    Elevator muscle activity per unit bite-force has been shown to be higher in chewing than in isometric biting. We tested the hypothesis that surplus elevator activity is evoked in response to a possible co-activation of jaw-opener muscles during the masticatory power stroke. In 32 subjects, digastric and bilateral masseter and temporalis activities were recorded during unilateral chewing of test foods, isometric biting on a force transducer, and during balancing of the jaw against maximum effort of depressor muscles. During elevator peak effort in chewing, the digastric activity was 113% higher than during peak effort in isometric biting. Comparison of balancing and chewing trials revealed that a 6% increase of elevator activity would suffice to compensate for this increased depressor action. Elevator activity in chewing, however, was up to 130% higher than in clenching. We conclude that depressor counteraction could have only a minor influence on the generation of surplus muscle activity in chewing.

  9. Reconstruction of the Orbit With a Temporalis Muscle Flap After Orbital Exenteration

    PubMed Central

    Uyar, Yavuz; Yıldırım, Güven; Kuzdere, Mustafa; Arbağ, Hamdi; Jorayev, Chary; Kılıç, Mehmet Vefa; Gümrükçü, Said Serdar

    2015-01-01

    Objectives This study presents the role of the temporalis muscle flap in primary reconstruction after orbital exenteration. Methods A retrospective nonrandomized study of orbital exenterations performed between 1990 and 2010 for malignant tumors of the skin, paranasal sinus, and nasal cavity is presented. Results The study included 13 patients (nine men, four women; age range, 30-82 years) with paranasal sinus, nasal cavity, or skin carcinomas. Primary reconstruction of the cavity was performed in all patients after orbital exenteration. No visible defects in the muscle flap donor site were present. Local recurrences were readily followed up with nasal endoscopy, whereas radiology helped to diagnose intracranial involvement in three patients. Two patients died of systemic metastases and five died for other reasons Conclusion The temporalis muscle flap is readily used to close the defect after orbital exenteration, and does not prevent the detection of recurrence. PMID:25729496

  10. Effects on craniofacial growth and development of unilateral botulinum neurotoxin injection into the masseter muscle.

    PubMed

    Tsai, Chi-Yang; Chiu, Wan Chi; Liao, Yi-Hsuan; Tsai, Chih-Mong

    2009-02-01

    The effects of botulinum neurotoxin type A (BoNT/A) on masseter muscles, when injected for cosmetic purposes (volumetric reduction) or treatment of excessive muscle activity (bruxism), have been investigated. However, the full anatomic effects of treatment are not known, particularly with respect to the mandible and relevant anthropometric measurements. The intent of this study was to use unilaterial BoNT/A injections to induce localized masseter atrophy and paresis and then to measure the effects of muscle influence on craniofacial growth and development. Growing male Wistar rats, 30 days old, were studied. The experimental group consisted of 8 rats. One side of the masseter muscle was injected with BoNT/A and the other side of the masseter muscle was injected with saline. The side with BoNT/A belonged to 1 group and the side with saline was the sham group. Three rats without injections was the control. After 45 days, the masseter muscles were dissected and weighed. Dry skulls were prepared, and anthropometric measurements determined. One-way ANOVA showed that the animals maintained their weight in both groups; however, the muscles injected with BoNT/A were smaller than the sham or control muscles. Anthropometric measurements of the bony structures attached to the masseter muscle showed a significant treatment effect. After localized masseter muscle atrophy induced by BoNT/A injection, alterations of craniofacial bone growth and development were seen. The results agree with the functional matrix theory that soft tissues regulate bone growth.

  11. Topographic anatomy of the masseter muscle focusing on the tendinous digitation.

    PubMed

    Lee, Ju-Young; Kim, Jeong-Nam; Yoo, Ja-Young; Hu, Kyung-Seok; Kim, Hee-Jin; Song, Wu-Chul; Koh, Ki-Seok

    2012-10-01

    The masseter muscle has superficial tendons that interdigitate like a saw (tendinous digitations), but a detailed description of these tendons is lacking in anatomic textbooks and atlases. The aim of the present study was to elucidate the topographic anatomy of the masseter muscle, focusing on its tendinous digitation. Sixty-five adult faces (113 sides) were dissected. Five parameters, including the lengths, widths, and thickness of the muscle, were measured. The number and morphology of tendinous digitations were also investigated. The length and width of the masseter muscle were longer and wider in male specimens than in female specimens. The number of masseter muscle tendinous digitations was predominantly two in males and three in females. The length of the tendinous digitations tended to be about three-quarters of that of the muscle. The second tendinous digitation was the longest in male specimens, while the first tendinous digitation was the longest in females. Based on our results, the external morphology of the masseter muscle does not match that described in anatomical atlases and textbooks. These findings may be helpful as a basic reference and in the treatment of masseter muscle hypertrophy and masseter tenomyositis. Copyright © 2012 Wiley Periodicals, Inc.

  12. Bilateral hypertrophy of masseteric and temporalis muscles, our fifteen patients and review of literature.

    PubMed

    Graziano, P; Dell'Aversana Orabona, G; Astarita, F; Ponzo, L M; Nunziata, R; Salzano, G; Maglitto, F; Solari, D; Santella, A; Cappabianca, M; Iaconetta, G; Califano, L

    2016-01-01

    The association of bilateral hypertrophy of temporalis and masseteric muscles is a rare clinical entity. The origin of the condition is unclear, causing cosmetic problems, pain, and functional impairment. In this paper we analyzed 15 patients treated at the Department of Maxillo-Facial Surgery of the University of Naples Federico II, from 2000 to 2013, for temporalis and/or masseteric muscle hypertrophy, and in particular, a rare case of a patient with a marked bilateral swelling of the temporalis and masseteric region, in conjunction with a review of the literature. Fourteen patients have not any kind of postoperatively problems. The last patient had been aware of the swelling for many years and complained of recurrent headaches. We adopted a new protocol fort this patients and the patient was very pleased with the treatment results, and reported a reduction in headaches and a continuation of his well-being, in addition to greater self-confidence. The last follow-up was performed three years after the first treatment, and the patient showed a complete resolution of his symptoms, and just a small increase of the swelling. The treatment of temporalis and masseteric hypertrophy with Botulin toxin could be an effective option compared to conservative treatment or surgical intervention, although the review of the literature shows that this is only a temporary treatment. In fact, surgery still remains the best option. The treatment must be repeated every 4/6 months for 2-3 consecutive years before having stable benefits. To overcome this problem, an association with a bite treatment allowed us to achieve more lasting and more stable results over time without a recurrence of symptoms between the treatments. Furthermore, this association has enabled us to obtain a more rapid reduction of the hypertrophy.

  13. Oronasal fistula repair utilizing a temporalis muscle flap in a dog with severe trismus.

    PubMed

    Cavanaugh, Ryan P; Farese, James P; Bacon, Nicholas J; Lurie, David M; Milner, Rowan J

    2011-01-01

    A 9 yr old spayed female cocker spaniel presented for evaluation of an invasive maxillary squamous cell carcinoma. Curative intent surgery and radiation therapy allowed for local control of the neoplasm; however, the development of a persistent oronasal fistula prevented a complete recovery. A temporalis myofascial rotation flap allowed for successful resolution of the maxillary defect. Implementation of the flap was relatively simple and was associated with few complications.

  14. Autogenous temporalis fascia patch graft for porous polyethylene (Medpor) sphere orbital implant exposure

    PubMed Central

    Sagoo, M S; Olver, J M

    2004-01-01

    Background: Temporalis fascia has been recommended for hydroxyapatite sphere exposure. The aim of this study was to identify potential risk factors for exposure of porous polyethylene (Medpor) sphere implants and evaluate the use of autogenous temporalis fascia as a patch graft for exposure. Methods: A retrospective review of consecutive cases of porous polyethylene sphere orbital implant exposure. Results: Five cases presented between May 2000 and October 2001 (three males, two females; mean age 44.5 years). Three had enucleation (two with primary implants) and two had evisceration (one with primary implant). Exposure occurred in one primary, two secondary, and two replacement implants. Orbital implant diameter was 20 mm in four cases and 16 mm in one case (contracted socket). The mean time from implantation to exposure was 23 months (range 0.7–42.6). Three patients had secondary motility peg placement before exposure. The average time from last procedure (sphere implant or peg insertion) to exposure was 3 months (range 0.7–12.6). Four patients required surgical intervention, of which three needed more than one procedure. Autogenous temporalis fascia grafting successfully closed the defect without re-exposure in three of these four patients. The grafts were left bare in three patients, with a mean time to conjunctivalise of 2.4 months (range 1.6–3.2). Conclusions: Exposed porous polyethylene sphere implants were treated successfully with autogenous temporalis fascia graft in three of four patients. This technique is useful, the graft easy to harvest, and did not lead to prolonged socket inflammation, infection, or extrusion. PMID:15205243

  15. Autogenous temporalis fascia patch graft for porous polyethylene (Medpor) sphere orbital implant exposure.

    PubMed

    Sagoo, M S; Olver, J M

    2004-07-01

    Temporalis fascia has been recommended for hydroxyapatite sphere exposure. The aim of this study was to identify potential risk factors for exposure of porous polyethylene (Medpor) sphere implants and evaluate the use of autogenous temporalis fascia as a patch graft for exposure. A retrospective review of consecutive cases of porous polyethylene sphere orbital implant exposure. Five cases presented between May 2000 and October 2001 (three males, two females; mean age 44.5 years). Three had enucleation (two with primary implants) and two had evisceration (one with primary implant). Exposure occurred in one primary, two secondary, and two replacement implants. Orbital implant diameter was 20 mm in four cases and 16 mm in one case (contracted socket). The mean time from implantation to exposure was 23 months (range 0.7-42.6). Three patients had secondary motility peg placement before exposure. The average time from last procedure (sphere implant or peg insertion) to exposure was 3 months (range 0.7-12.6). Four patients required surgical intervention, of which three needed more than one procedure. Autogenous temporalis fascia grafting successfully closed the defect without re-exposure in three of these four patients. The grafts were left bare in three patients, with a mean time to conjunctivalise of 2.4 months (range 1.6-3.2). Exposed porous polyethylene sphere implants were treated successfully with autogenous temporalis fascia graft in three of four patients. This technique is useful, the graft easy to harvest, and did not lead to prolonged socket inflammation, infection, or extrusion.

  16. Is the long-latency stretch reflex in human masseter transcortical?

    PubMed

    Pearce, Sophie L; Miles, Timothy S; Thompson, Philip D; Nordstrom, Michael A

    2003-06-01

    A long-latency stretch reflex (LLSR) has been described in the human masseter muscle, but its pathway remains uncertain. To investigate this, the excitability of corticomotoneuronal (CM) cells projecting to masseter motoneurons during the LLSR was assessed with transcranial magnetic stimulation (TMS). A facilitated response to TMS would be evidence of a LLSR pathway that traverses the motor cortex. Surface electromyogram electrodes were placed over the left or right masseter, and subjects ( n=10) bit on bars with their incisor teeth at 10% of maximal electromyographic activity (EMG). Servo-controlled displacements were imposed on the lower jaw to evoke a short- and long-latency stretch reflex in masseter. TMS intensity was just suprathreshold for a response in contralateral masseter. Trials consisted of: (1) stretch alone, (2) TMS alone, and (3) TMS with a preceding conditioning stretch at varied conditioning-testing (C-T) intervals chosen to combine TMS with the short-latency stretch reflex (3 ms, 5 ms) and the LLSR (23-41 ms). Masseter EMG was rectified and averaged. With TMS alone, mean (+/- SE) MEP area above baseline was 56+/-9%. The area of masseter MEPs above baseline in the C-T trials was calculated from each EMG average following subtraction of the response to stretch alone. Conditioning muscle stretch had no significant effect on masseter MEPs evoked by TMS with any C-T interval (ANOVA; P=0.90). In addition, subjects were unable to modify the SLSR or LLSR by voluntary command. It is concluded that the long-latency stretch reflex in the masseter does not involve the motor cortex and is not influenced by "motor set".

  17. Role of temporalis muscle over activity in chronic tension type headache: effect of yoga based management.

    PubMed

    Bhatia, R; Dureja, G P; Tripathi, M; Bhattacharjee, M; Bijlani, R L; Mathur, R

    2007-01-01

    The role of central versus peripheral mechanisms has always been questioned while explaining the etiopathogenesis of chronic tension type headache (CTTH). The following study was done to study the role of muscle spasm in CTTH. 15 patients of CTTH and 7 age matched controls were included in the study and their m. temporalis EMG was recorded for one minute each during rest, mental activity and maximal voluntary contraction and subjective pain scoring was done by visual analogue scale. The results revealed significant overactivity of m.temporalis in CTTH patients at rest when compared with control subjects (P = 0.01 and 0.03 left and right side respectively). After respective interventions namely non steroidal anti inflammatory drugs, botulinum toxin injections and yogic life style course, the EMG records revealed decrease in the mean EMG amplitude of m. temporalis during rest and mental activity more significantly after yoga based interventions (P = 0.03) and subjective pain scores decreased from 7.00 +/- 2.10 to 2.00 +/- 1.26 (P = 0.02) supporting the beneficial effect of such non invasive techniques.

  18. Revisiting Orthodromic Temporalis Transfer in Treating Long-Standing Facial Paralysis

    PubMed Central

    Elbarbary, Amir S.; Hemeda, Mostafa; Amr, Adel H.

    2010-01-01

    The treatment of long-standing facial paralysis through temporalis muscle transfer has stood the test of time. Herein, we present a modification in temporalis muscle transfer for lower facial reanimation. Instead of the traditional stripping of the temporalis muscle from its origin, its insertion is stripped from the coronoid process through an intraoral approach. The detached fibers were then sutured to a fascia lata graft, which was passed and secured to the orbicularis oris to reanimate the corner of the mouth. The procedure is less extensive and provides a direct “orthodromic” line of pull with good muscular excursion and power. This simple procedure has been applied to 12 consecutive cases with long-standing complete facial paralysis presenting to the Plastic and Reconstructive Surgery Clinic at the Ain-Shams University Hospital over the past 2 years. In addition to symmetry at rest, this easy procedure allowed for good movement of the corner of the mouth with restoration of a balanced smile. PMID:22110814

  19. Nociceptive temporalis inhibitory reflexes evoked by CO2-laser stimulation in tension-type headache.

    PubMed

    de Tommaso, M; Guido, M; Libro, G; Losito, L; Sciruicchio, V; Specchio, L M; Puca, F

    2003-06-01

    The aim of the study was to evaluate the laser-induced suppression periods of the temporalis muscle in patients with tension-type headache, compared with the pattern of temporalis activity suppression induced by electrical stimulation. Fifteen patients with chronic and 10 with episodic tension-type headaches were selected. Suppression periods were recorded simultaneously from both temporalis muscles using both electrical stimuli and CO2-laser stimuli. A significant reduction in the later electrically induced suppression period was found in both tension-type headache groups. Laser stimulation induced a first suppression period (LSP1) with a latency of about 50 ms in all patients. The features of LSP1 were similar across groups. The LSP1 should correspond to the first suppression period induced by electrical stimulus, which is partly a nociceptive response, whereas the second period seemed negligibly linked with the activation of pain-related afferents, though probably their activation may contribute to increase the reflex duration and to emphasize abnormalities in tension-type headache.

  20. The influence of pain on masseter spindle afferent discharge.

    PubMed

    Capra, Norman F; Hisley, Calvin K; Masri, Radi M

    2007-04-01

    Muscle spindles provide proprioceptive feedback supporting normal patterns of motor activity and kinesthetic sensibility. During mastication, jaw muscle spindles play an important role in monitoring and regulating the chewing cycle and the bite forces generated during mastication. Both acute and chronic orofacial pain disorders are associated with changes in proprioceptive feedback and motor function. Experimental jaw muscle pain also alters the normal response of masseter spindle afferents to ramp and hold jaw movements. It has been proposed that altered motor function and proprioceptive input results from group III muscle afferent modulation of the fusimotor system which alters spindle afferent sensitivity in limb muscles. The response to nociceptive stimuli may enhance or reduce the response of spindle afferents to proprioceptive stimuli. Several experimental observations suggesting the possibility that a similar mechanism also functions in jaw muscles are presented in this report. First, evidence is provided to show that nociceptive stimulation of the masseter muscle primarily influences the amplitude sensitivity of spindle afferents with relatively little effect on the dynamic sensitivity. Second, reversible inactivation of the caudal trigeminal nuclei attenuates the nociceptive modulation of spindle afferents. Finally, functionally identified gamma-motoneurons in the trigeminal motor nucleus are modulated by intramuscular injection with algesic substances. Taken together, these results suggest that pain-induced modulation of spindle afferent responses are mediated by small diameter muscle afferents and that this modulation is dependent, in part, on the relay of muscle nociceptive information from trigeminal subnucleus caudalis onto trigeminal gamma-motoneurons. The implication of these results will be considered in light of current theories on the relationship between jaw muscle pain and oral motor function.

  1. The Influence of Pain on Masseter Spindle Afferent Discharge

    PubMed Central

    Capra, Norman F.; Hisley, Calvin K.; Masri, Radi M.

    2007-01-01

    Summary Muscle spindles provide proprioceptive feedback supporting normal patterns of motor activity and kinesthetic sensibility. During mastication, jaw muscle spindles play an important role in monitoring and regulating the chewing cycle and the bite forces generated during mastication. Both acute and chronic orofacial pain disorders are associated with changes in proprioceptive feedback and motor function. Experimental jaw muscle pain also alters the normal response of masseter spindle afferents to ramp and hold jaw movements [1]. It has been proposed that altered motor function and proprioceptive input results from group III muscle afferent modulation of the fusimotor system which alters spindle afferent sensitivity in limb muscles[2]. The response to nociceptive stimuli may enhance or reduce the response of spindle afferents to proprioceptive stimuli. Several experimental observations suggesting the possibility that a similar mechanism also functions in jaw muscles are presented in this report. First, evidence is provided to show that nociceptive stimulation of the masseter muscle primarily influences the amplitude sensitivity of spindle afferents with relatively little effect on the dynamic sensitivity [3]. Second, reversible inactivation of the caudal trigeminal nuclei attenuates the nociceptive modulation of spindle afferents. Finally, functionally identified gamma-motoneurons in the trigeminal motor nucleus are modulated by intramuscular injection with algesic substances. Taken together, these results suggest that pain-induced modulation of spindle afferent responses are mediated by small diameter muscle afferents and that this modulation is dependent, in part, on the relay of muscle nociceptive information from trigeminal subnucleus caudalis onto trigeminal gamma-motoneurons. The implication of these results will be considered in light of current theories on the relationship between jaw muscle pain and oral motor function. PMID:17126284

  2. Genetic stretching factors in masseter muscle after orthognathic surgery.

    PubMed

    Breuel, Wiebke; Krause, Micaela; Schneider, Matthias; Harzer, Winfried

    2013-09-01

    Up to 30% of patients relapse after orthognathic operations, and one reason might be incomplete neuromuscular adaptation of the masticatory muscles. Displacement of the mandible in sagittal or vertical directions, or both, leads to stretching or compression of these muscles. The aim of this study was to analyse stretching factors in 35 patients with retrognathism or prognathism of the mandible (Classes II and III). Tissue samples were taken from both sides of the masseter muscle (anterior and posterior) both before and 6 months after operation. Developmental myosin heavy chains MYH3 and MYH8, the fast and slow MYH 1, 2, and 7, and cyclo-oxygenase (COX) 2, forkhead transcription factor (FOX)O3a, calcineurin, and nuclear factor of activated T cells (NFAT)1c (stretching and regeneration-specific), were analysed by real time polymerase chain reaction (PCR). Correlations of Class II and III with sagittal and vertical cephalometric measurements ANB and ML-NL-angle were examined, and the results showed significant differences in amounts of MYH8 (p<0.05), MYH1 (p<0.05), and FOXO3a (p<0.05) between the 2 groups. Regeneration factor COX2 is more dominant in Class II. Surgically, bite opening (ML/NL angle) correlated with stretching indicators FOXO3a, calcineurin, and NFAT1c only in Class II patients. This means that stretching of the masseter muscle caused by lengthening of the mandible and raising of the bite in Class II patients was more likely to lead to relapse (similar to that in patients with open bite) than in Class III patients. In conclusion, deep bite should be reduced more by incisor intrusion than by skeletal opening. The focus in these patients should be directed towards physiotherapeutic strengthening of the muscles of mastication, and more consideration should be given to change in the vertical dimension.

  3. 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.

  4. Reduction of pain and EMG activity in the masseter region by trapezius trigger point injection.

    PubMed

    Carlson, C R; Okeson, J P; Falace, D A; Nitz, A J; Lindroth, J E

    1993-12-01

    In this open, uncontrolled trial, 20 patients with upper trapezius muscle trigger point pain and ipsilateral masseter muscle pain received a single trigger point injection of 2% lidocaine solution (without epinephrine) in the upper trapezius muscle. Following the trapezius injection, there was a significant (P < 0.001) reduction in pain intensity ratings for pain in the masseter region. In addition, there was a significant (P < 0.03) reduction in EMG activity in the masseter muscle. Overall, however, a significant relationship between EMG activity in the masseter and the self-report of pain was not found with the present data set. These clinical findings support the contention that sources of deep pain can produce heterotopic sensory and motor changes in distant anatomical regions.

  5. Malignant myoepithelioma arising in salivary tissue on the masseter muscle: US, CT, and MR findings

    SciTech Connect

    Martinoli, C.; Cittadini, G.; Derchi, L.E.; Rollandi, G.A.

    1996-01-01

    We report the US, CT, and MR appearances of a malignant myoepithelioma arising on the masseter muscle from aberrant salivary tissue, associated with postobstructive atrophy of the main parotid gland. 13 refs., 4 figs.

  6. Ultrasonographic thickness and electromyographic activity of masseter muscle of human females.

    PubMed

    Georgiakaki, I; Tortopidis, D; Garefis, P; Kiliaridis, S

    2007-02-01

    The aims of this study were to assess the thickness of the masseter muscle by means of ultrasonography and to investigate the relationship between masseter electromyographic activity and muscle thickness bilaterally, during maximum voluntary clenches. Participants in the study consisted of 52 young female adults (mean age 23.7 +/- 2.5 years) without craniomandibular disorders and with full natural dentitions. The thickness of the masseter muscle was measured with a real-time ultrasound equipment. Electromyographic activity was recorded with bipolar surface electrodes, during maximum voluntary clenches. The error of the methods was calculated by double recordings in 15 subjects in a 4-week interval. The measurement error for the right muscle was 0.16 mm in thickness and 16.44 microV in electromyographic activity. For the left masseter the corresponding values were 0.19 mm and 18.01 microV. The relationship of masseter muscle thickness to its electromyographic activity was estimated by Pearson's correlation coefficient. The mean masseter thickness under contracted conditions was 13.9 +/- 1.5 mm for the right side and 13.9 +/- 1.4 mm for the left side. The mean maximum electromyographic activity was 379.0 +/- 56.0 microV for the right muscle and 372.3 +/- 73.2 microV for the left. Muscle thickness was strongly correlated to electromyographic maximum activity in the right masseter (r = 0.721, P < or = 0.001) and moderately correlated in the left muscle (r = 0.407, P < or = 0.01). The difference between the two sides is possibly because of the larger method error in the left side. It is apparent that ultrasonography can be used as a useful tool to assess masseter muscle functional capacity during full effort in healthy individuals.

  7. Reduced masticatory function is related to lower satellite cell numbers in masseter muscle.

    PubMed

    Kuijpers, M A R; Grefte, S; Bronkhorst, E M; Carels, C E L; Kiliaridis, S; Von den Hoff, J W

    2014-06-01

    The physiology of masseter muscles is known to change in response to functional demands, but the effect on the satellite cell (SC) population is not known. In this study, the hypothesis is tested that a decreased functional demand of the masseter muscle causes a reduction of SCs. To this end, twelve 5-week-old male Sprague-Dawley rats were put on a soft diet (SD, n = 6) or a hard diet (HD, n = 6) and sacrificed after 14 days. Paraffin sections of the superficial masseter and the m. digastricus (control muscle) were stained with haematoxylin and eosin for tissue survey and with anti-myosin heavy chain (MHC) for slow and fast fibres. Frozen sections of both muscles were double-stained for collagen type IV and Pax7. Slow MHC fibres were equally distributed in the m. digastricus but only localized in a small area of the m. masseter. No differences between HD or SD for the m. digastricus were found. The m. masseter had more SCs per fibre in HD than in SD (0.093 ± 0.007 and 0.081 ± 0.008, respectively; P = 0.027). The m. masseter had more fibres per surface area than the m. digastricus in rats with an SD group (758.1 ± 101.6 and 568.4 ± 85.6, P = 0.047) and a HD group (737.7 ± 32.6 and 592.2 ± 82.2; P = 0.007). The m. digastricus had more SCs per fibre than the m. masseter in the SD group (0.094 ± 0.01 and 0.081 ± 0.008; P = 0.039). These results suggest that reduced masseter muscle function is related to a lower number of SCs. Reduced muscle function might decrease microdamage and hence the requirement of SCs in the muscle fibres.

  8. Muscle force recruitment and biomechanical modeling: an analysis of masseter muscle function during mastication in Macaca fascicularis.

    PubMed

    Hylander, W L; Johnson, K R; Crompton, A W

    1992-07-01

    The main purpose of this study is to test the hypothesis that as subjects chew with increasing levels of force, the ratio of the working- to balancing-side jaw-muscle force (W/B) decreases and begins to approach 1.0. We did this by analyzing relative masseter force in Macaca fascicularis using both strain gage and surface electromyographic (EMG) techniques. In addition, we also analyzed: 1) the relationship between jaw position using cineradiographic techniques and relative masseter force, 2) the timing differences between relative masseter force from the working and balancing sides, and 3) the loading and unloading characteristics of the masseter muscle. Our findings indicate that when macaques increase the amount of overall masticatory force during chewing, the W/B ratio for masseter force frequently (but not always) decreases and begins to approach 1.0. Therefore, our working hypothesis is not completely supported because the W/B ratio does not decrease with increasing levels of force in all subjects. The data also demonstrate timing differences in masseter force. During apple-skin mastication, the average peak masseter force on the working side occurs immediately at or slightly after the initial occurrence of maximum intercuspation, whereas the average peak masseter force on the balancing side occurs well before maximum intercuspation. On average, we found that peak force from the balancing-side masseter precedes the working-side masseter by about 26 msec. The greater the asynchrony between working- and balancing-side masseter force, the greater the difference in the relative magnitude of these forces. For example, in the subject with the greatest asynchrony, the balancing-side masseter had already fallen to about one-half of peak force when the working-side masseter reached peak force. Our data also indicate that the loading and unloading characteristics of the masseter differ between the working and balancing sides. Loading (from 50 to 100% of peak force) and

  9. In vivo excursion of the temporalis muscle-tendon unit using electrical stimulation: application in the design of smile restoration surgery following facial paralysis.

    PubMed

    Boahene, Kofi D O; Ishii, Lisa E; Byrne, Patrick J

    2014-01-01

    The temporalis muscle has the potential to substitute for the function of paralyzed facial muscles in a single-stage procedure when transferred as a muscle-tendon unit (MTU). To measure the available excursion of the temporalis MTU after release from the coronoid. DESIGN, SETTING, AND PARTICIPANTS Thirteen consecutive patients undergoing the temporalis MTU transfer procedure for facial reanimation participated in this study in an academic research setting. Using transcutaneous electrical stimulation of the temporalis muscle, excursion of the temporalis muscle after its release as an MTU was recorded. Tension was varied on the released tendon during electrical stimulation of the muscle to determine the optimal muscle length at which the maximum excursion could be achieved. The tendon was inserted at the modiolus at the determined muscle length, and excursion of the oral commissure was recorded. Excursion data were then measured from the video recordings. RESULTS The mean excursion of the temporalis tendon after its detachment from the mandible and stimulation at an optimized passive tension was 20.6 mm (range, 14-30 mm) (n = 9). Following tendon insertion, the mean oral commissure excursion was 15.5 mm (range, 8-23 mm) (n = 13). The temporalis MTU has adequate available excursion following mobilization for dynamic reanimation of the paralyzed face. Electrical stimulation of the released temporalis tendon gives useful information that is reproducible and can be an important intraoperative adjunct to setting the MTU at an optimal tension to maximize force generation and excursion. NA.

  10. A comprehensive approach to long-standing facial paralysis based on lengthening temporalis myoplasty.

    PubMed

    Labbè, D; Bussu, F; Iodice, A

    2012-06-01

    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 20(th) 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 20(th) 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 comprehensive

  11. Principles and biomechanics of muscle tendon unit transfer: application in temporalis muscle tendon transposition for smile improvement in facial paralysis.

    PubMed

    Boahene, Kofi D O

    2013-02-01

    Muscle tendon unit (MTU) transfer is a common procedure performed to restore hand function after peripheral nerve or spinal cord injury. The principles of MTU transfer established for hand surgery can be adopted to optimize the dynamic excursion of the temporalis tendon transfer procedure for facial reanimation. Additionally, the force generating ability of a transferred MTU depends on the ideal length-tension relationship of the donor muscle. There are unclear guideline for selecting the ideal tension at which a transferred MTU will generate maximum force and excursion and current practice often leads to overstretch and suboptimal actin myosin interaction. The use of intraoperative electrical stimulation is an option for determining the ideal tension to optimize excursion of transferred temporalis tendon units in simile restoration. Understanding the biomechanics and principles of MTU and applying it to the temporalis tendon transfer procedure is necessary to improve its use in facial reanimation. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  12. Comparative analysis of masseter fiber architecture in tree-gouging (Callithrix jacchus) and nongouging (Saguinus oedipus) callitrichids.

    PubMed

    Taylor, Andrea B; Vinyard, Christopher J

    2004-09-01

    Common marmosets (Callithrix jacchus) and cotton-top tamarins (Saguinus oedipus) (Callitrichidae, Primates) share a broadly similar diet of fruits, insects, and tree exudates. Common marmosets, however, differ from tamarins by actively gouging trees with their anterior teeth to elicit tree exudate flow. During tree gouging, marmosets produce relatively large jaw gapes, but do not necessarily produce relatively large bite forces at the anterior teeth. We compared the fiber architecture of the masseter muscle in tree-gouging Callithrix jacchus (n = 10) to nongouging Saguinus oedipus (n = 8) to determine whether the marmoset masseter facilitates producing these large gapes during tree gouging. We predict that the marmoset masseter has relatively longer fibers and, hence, greater potential muscle excursion (i.e., a greater range of motion through increased muscle stretch). Conversely, because of the expected trade-off between excursion and force production in muscle architecture, we predict that the cotton-top tamarin masseter has more pinnate fibers and increased physiological cross-sectional area (PCSA) as compared to common marmosets. Likewise, the S. oedipus masseter is predicted to have a greater proportion of tendon relative to muscle fiber as compared to the common marmoset masseter. Common marmosets have absolutely and relatively longer masseter fibers than cotton-top tamarins. Given that fiber length is directly proportional to muscle excursion and by extension contraction velocity, this result suggests that marmosets have masseters designed for relatively greater stretching and, hence, larger gapes. Conversely, the cotton-top tamarin masseter has a greater angle of pinnation (but not significantly so), larger PCSA, and higher proportion of tendon. The significantly larger PCSA in the tamarin masseter suggests that their masseter has relatively greater force production capabilities as compared to marmosets. Collectively, these results suggest that the fiber

  13. Lengthening Temporalis Myoplasty: Objective Outcomes and Site-Specific Quality-of-Life Assessment.

    PubMed

    Panciera, Davide Thomas; Sampieri, Claudio; Deganello, Alberto; Danesi, Giovanni

    2017-06-01

    Objective Evaluate outcomes of the lengthening temporalis myoplasty in facial reanimations. Study Design Case series with planned data collection. Setting Ospedali Riuniti, Bergamo, and AOUC Careggi, Florence, Italy. Subjects and Methods From 2011 to 2016, 11 patients underwent lengthening temporalis myoplasty; demographic data were collected for each. Pre- and postoperative photographs and videos were recorded and used to measure the smile angle and the excursion of the oral commissure, according to the SMILE system (Scaled Measurements of Improvement in Lip Excursion). All patients were tested with the Facial Disability Index, and they also completed a questionnaire about the adherence to physiotherapy indications. Results All patients demonstrated a significant improvement in functional parameters and in quality of life. On the reanimated side, the mean z-line and a-value, measured when smiling, significantly improved in all patients: from 22.6 mm (95% CI, 20.23-25.05) before surgery to 30.9 mm (95% CI, 27.82-33.99) after surgery ( P < .001) and from 100.5° (95% CI, 93.96°-107.13°) to 111.6° (95% CI, 105.63°-117.64°; P < .001), respectively. The mean postoperative dynamic gain, passing from rest to a full smile at the reanimated side, was 3.1 mm (95% CI, 1.30-4.88) for the z-line and 3.3° (95% CI, 1.26°-5.29°) for the a-value. The Facial Disability Index score increased from a preoperative mean of 33.4 points (95% CI, 28.25-38.66) to 49.9 points (95% CI, 47.21-52.60) postoperatively ( P < .001). Conclusions The lengthening temporalis myoplasty can be successfully used for smile reanimation, with satisfying functional and quality-of-life outcomes.

  14. Effect of conditioning electrical stimuli on temporalis electromyographic activity during sleep.

    PubMed

    Jadidi, F; Castrillon, E; Svensson, P

    2008-03-01

    Inhibitory reflexes during voluntary contractions are well described; however, few studies have attempted to use such reflex-mechanisms to modulate electromyographic (EMG) activity in jaw-closing muscles during sleep. The aim was to apply a new intelligent biofeedback device (Grindcare(R)) using electrical pulses to inhibit EMG activity in the temporalis muscle during sleep. Fourteen volunteers participated who were aware of jaw-clenching activity as indicated by complaints from sleep partner, soreness or pain in the jaw-muscle upon awakening and tooth wear facets. The EMG activity was recorded from the temporalis muscle, online analysed and the frequency content determined using a signal recognition algorithm. Based on specific individual parameters for pattern recognition, an electrical square-wave pulse train, which was adjusted to a clear, but non-painful intensity (range 1-7 mA) was applied through the EMG electrodes, if jaw-clenching activity was detected. All volunteers had baseline EMG recordings for five to seven consecutive nights, followed by 3-weeks EMG recordings with the feedback turned on, 2 weeks without the feedback and finally 3 weeks with the biofeedback on. There were no session effects on the average duration of sleep hours (P = 0.626). The number of EMG episodes/hour sleep was significantly reduced during the two sessions with biofeedback (54 +/- 14%; 55 +/- 17%, P < 0.001) compared with baseline EMG activity and the session without biofeedback. The present study suggests that biofeedback with electrical pulses does not cause major disruption in sleep and is associated with pronounced reduction in temporalis EMG activity during sleep.

  15. The epithelialization process in the healing temporalis myofascial flap in oral reconstruction.

    PubMed

    Cheung, L K

    1997-08-01

    The aim of this study was to investigate prospectively the epithelialization process in the healing temporalis myofascial flap (TMF). Eight cats underwent maxillectomy and immediate reconstruction with TMF. They were killed at the determined time and the reconstructed maxillae were processed for examination by light microscopy and scanning electron microscopy. Results revealed that epithelialization of the healing TMF was initiated by hyperplastic changes followed by active migration of epithelial cells deriving from the wound margins. The partial maxillectomy wound was completely covered by a smooth oral mucosa at postoperative week 24. The mucosa had histological and ultrastructural features different from normal palatal mucosa.

  16. Activation of the masseter muscle during normal smile production and the implications for dynamic reanimation surgery for facial paralysis.

    PubMed

    Schaverien, Mark; Moran, Gregory; Stewart, Ken; Addison, Patrick

    2011-12-01

    In cases of unilateral facial paralysis, free muscle transfer with coaptation to the motor nerve of the Masseter is gaining popularity as a primary alternative to cross-facial nerve grafting. Despite initial expectations, a majority of these subjects can achieve a spontaneous smile. The mechanism behind this spontaneity is unclear. Plasticity of the cerebral cortex as well as the relative proximity of the motor centres of the mimetic and Masseter muscles has been used in explanation. This study demonstrates the involvement of the Masseter muscle during normal smile production, suggesting a more direct explanation for the spontaneous smile seen following reanimation procedures innervated by the Masseter nerve. Twenty healthy volunteers were subjected to electromyography of the Masseter muscle bilaterally to demonstrate whether contraction of the Masseter muscle occurred during voluntary and involuntary smile production. Patient age ranged from 20 to 61 years (mean 41.6 years) with an equal male to female ratio. Activation of the Masseter occurred in 40 percent of individual muscles during smile production, occurring bilaterally in six participants, and unilaterally in four. There was no correlation between muscle activation and patient age or gender. Natural contraction of the Masseter muscle during normal smile production helps to explain the high rate of spontaneous smile development in subjects with facial paralysis who have undergone a free muscle reanimation procedure powered by the nerve to the Masseter muscle. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Technique for fixing a temporalis muscle using a titanium plate to the implanted hydroxyapatite ceramics for bone defects.

    PubMed

    Ono, I; Tateshita, T; Sasaki, T; Matsumoto, M; Kodama, N

    2001-05-01

    We devised a technique to fix the temporalis muscle to the transplanted hydroxyapatite implant by using a titanium plate, which is fixed to the hydroxyapatite ceramic implant by screws and achieves good clinical results. The size, shape, and curvature of the hydroxyapatite ceramic implants were determined according to full-scale models fabricated using the laser lithographic modeling method from computed tomography data. A titanium plate was then fixed with screws on the implant before implantation, and then the temporalis muscle was refixed to the holes at both ends of the plate. The application of this technique reduced the hospitalization time and achieved good results esthetically.

  18. 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.

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

    PubMed

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

    2015-01-01

    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. 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. 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-induced muscle atrophy.

  20. Botulinum neurotoxin effects on masseter muscle fibre in WNIN obese rats-Scanning electron microscope analysis.

    PubMed

    Nemani, Shivaram; Putchha, Uday K; Periketi, Madhusudhanachary; Pothana, Sailaja; Nappanveettil, Giridharan; Nemani, Harishankar

    2016-09-01

    WNIN/Ob obese mutant rats are unique in comparison to similar rodent models of obesity established in the West. The present study is aimed to evaluate the masticatory function and histological changes in masseter muscle fibres treated with botulinum toxin type A (BoNT/A) in WNIN/Ob rats. Twelve WNIN/Ob obese rats and 12 lean rats at 35 days of age were taken and divided into four groups (6 rats in each group): Group-I (WNIN/Ob) and Group-II (lean) rats were injected with BoNT/A (1 unit) into right side of masseter muscle. For control left masseter of both phenotypes was injected with saline. Group-III (WNIN/Ob) and Group-IV (lean) rats were without any treatment. Growth and food intake was monitored daily for 45 days. Rats were euthanized and gross necropsy was carried out to check any abnormalities. Masseter muscles were dissected and mean muscle mass was recorded. Small portion of muscle was stored in 10% formalin for hematoxylin-eosin (H&E) staining and remaining tissue stored in gluteraldehyde for scanning electron microscopy (SEM). There is a significant decrease in the body weights and food intake of BoNT/A treated obese rats. The H&E staining of the masseter muscle in both groups showed normal morphology and orientation. The SEM analysis showed that, fibre size in BoNT/A treated masseter muscle of obese rats increased more than the saline treated side and in control rats. The increase in the muscle fibre size and transition of muscle fibre subtypes may be due to the reduced masticatory function of the masseter muscle. SCANNING 38:396-402, 2016. © 2015 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

  1. 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

  2. Modulation of an inhibitory reflex in single motor units in human masseter by tonic painful stimulation.

    PubMed

    Svensson, P; McMillan, A S; Graven-Nielsen, T; Wang, K; Arendt-Nielsen, L

    1999-12-01

    Perioral electrical stimuli cause inhibitory reflex responses in single motor-units (SMU) and surface electromyographic (EMG) recordings from voluntary contracted human jaw-closing muscles. Tonic experimental masseter pain has recently been shown to reduce the inhibitory reflex response in surface EMG recordings but the effect on SMU activity has not been described. In this study, motor-unit action potentials were recorded with wire electrodes inserted into the left masseter in eleven subjects. The subjects kept the SMU firing rate around 10 Hz by feedback. Ninety-nine electrical stimuli were applied sequentially to the left mental nerve with increasing stimulus delays in steps of 1 ms after the preceding motor unit action potential. The inhibitory reflex in SMU was recorded before, during and after infusion of hypertonic saline (5%) into the ipsilateral masseter muscle. Spike train data were used to calculate (1) the mean pre- and post-stimulus inter-spike-intervals (ISI) in all of the 99 trials, (2) cumulative changes in firing probability, and (3) estimation of the compound inhibitory post-synaptic potential (IPSP) in the masseter motoneuron. Tonic masseter pain did not change pre-stimulus SMU firing characteristics but the mean ISI for the first post-stimulus discharge (158.2+/-9.2 ms) was significantly decreased compared to the pre-pain (175.8+/-11.3 ms, P<0.05) and post-pain conditions (172. 6+/-11.6 ms, P<0.05). The post-stimulus firing probability was significantly increased and the relative amplitude of the estimated IPSP significantly decreased during tonic masseter pain compared to pre-pain and post-pain conditions. In conclusion, this study indicates that tonic masseter pain has a net excitatory effect on the inhibitory jaw-reflexes, which could be mediated by presynaptic mechanisms on the involved motoneurons.

  3. [Blink and masseter inhibitory reflexes in Parkinson's disease].

    PubMed

    Stamenović, Jelena; Djurić, Stojanka; Djurić, Vanja

    2010-03-01

    Idiopathic Parkinson's disease (PD) is a chronic, progressive, neurodegenerative disorder with prevalence from 60 to 187 per 100 000 persons in general population. The aim of the study was to determine the abnormalities of the blink reflex (BR) and the masseter inhibitory reflex (MIR) in parkinsonian patients, as indices of the functional status of brainstem neuronal network, and abnormality level dependence on disease progression. The investigation was conducted at the Clinic of Neurology, Clinical Center Nis, comprising a group of 60 subjects of both sexes, suffering from idiopathic Parkinson's disease in I-IV stages, according to the Hoehn and Yahr scale. The control group included 30 healthy subjects of both sexes and corresponding age. Testing of the patients was performed during the "on" phase by registering MIR and BR. Latency of polysynaptic R2 and R2' blink reflex responses and latency of polysynaptic S2 response, as well as a silent period of MIR, are linearly shortened in the subjects with PD, and more expressed in the subsequent stages of the disease compared to the control group. There is a positive correlation between the applied neurophysiological tests results and clinical stage of PD.

  4. Replicability of electromyographic recordings of the masseter muscle during mastication.

    PubMed

    Garrett, N R; Kapur, K K

    1986-03-01

    This study evaluates the reliability of a method to duplicate the location of surface electrodes for recording the electromyographic activity of masseter muscles during mastication and quantifying the activity by a microcomputer system. A plastic framework consisting of a bite fork and electrode positioners was used to place the electrodes by relating the positioners to an occlusal index and keeping this relationship constant at subsequent sittings. EMG recordings were repeated on two different days for each of 10 subjects while they performed standardized masticatory performance tests with peanuts and carrots. The muscle activity recorded with hardware integrators was an average of 26.7% of the computerized software integrations but measures derived from the two methods of integration were highly correlated (r = 0.965) and yielded similar results. Significant correlations were found between test sessions for each measure of masticatory performance and integrated EMG activity for ipsilateral and contralateral muscles. For each subject, no significant differences were found between sessions for any masticatory performance or EMG variable. The results indicate that reliable inter session EMG recordings during mastication can be made by using the template for positioning of the electrodes. In addition, the microcomputer data acquisition system provides results comparable to those obtained with conventional hardware integrators, with the added benefit of providing information on each individual stroke and its various components.

  5. The role of P2X3 receptors in bilateral masseter muscle allodynia in rats

    PubMed Central

    Tariba Knežević, Petra; Vukman, Robert; Antonić, Robert; Kovač, Zoran; Uhač, Ivone; Simonić-Kocijan, Sunčana

    2016-01-01

    Aim To determine the relationship between bilateral allodynia induced by masseter muscle inflammation and P2X3 receptor expression changes in trigeminal ganglia (TRG) and the influence of intramasseteric P2X3 antagonist administration on bilateral masseter allodynia. Methods To induce bilateral allodynia, rats received a unilateral injection of complete Freund’s adjuvant (CFA) into the masseter muscle. Bilateral head withdrawal threshold (HWT) was measured 4 days later. Behavioral measurements were followed by bilateral masseter muscle and TRG dissection. Masseter tissue was evaluated histopathologically and TRG tissue was analyzed for P2X3 receptor mRNA expression by using quantitative real-time polymerase chain reaction (PCR) analysis. To assess the P2X3 receptor involvement in nocifensive behavior, two doses (6 and 60 μg/50 μL) of selective P2X3 antagonist A-317491 were administrated into the inflamed masseter muscle 4 days after the CFA injection. Bilateral HWT was measured at 15-, 30-, 60-, and 120-minute time points after A-317491 administration. Results HWT was bilaterally reduced after the CFA injection (P < 0.001). Intramasseteric inflammation was confirmed ipsilaterally to the CFA injection. Quantitative real-time PCR analysis demonstrated enhanced P2X3 expression in TRG ipsilaterally to CFA administration (P < 0.01). In comparison with controls, the dose of 6 μg of A-317491 significantly increased bilateral HWT at 15-, 30-, and 60-minute time points after the A-317491 administration (P < 0.001), whereas the dose of 60 μg of A-317491 was efficient at all time points ipsilaterally (P = 0.004) and at 15-, 30-, and 60-minute time points contralaterally (P < 0.001). Conclusion Unilateral masseter inflammation can induce bilateral allodynia in rats. The study provided evidence that P2X3 receptors can functionally influence masseter muscle allodynia and suggested that P2X3 receptors expressed in TRG neurons are involved in masseter

  6. [Adaptive change of masseter muscle after the ostectomy of mandibular angle in rabbits].

    PubMed

    Jia, Xue-feng; Huang, Jin-long

    2006-11-01

    To study the changes of masseter muscle after reducing the mandibular by measuring some relative index after ostectomy of the mandibular angle along arch line. Left mandibular angle ostectomy was performed on New Zealand female rabbits aged three months. The right was not operated as control groups. Five rabbits were examined at the following intervals: 2, 4, 8, 12 and 24 weeks. There were remarkable decreases in the experimented masseter muscle masses and the same type muscle fiber areas compared with the control group (P < 0.05). As for the fiber types, a decrease in type I fibers and an increase in type II fibers were noticed on operative side masseters (P <0.05). Sarcomere lengths in the operative side muscles were significantly reduced and showed statistical significance during first 4 weeks (P < 0.05), but there was no difference between the operative group and the control group after 8 weeks (P > 0.05). The changes of masseter fibres show reconstruction of masseter muscle after mandibular angle ostectomy.

  7. Efficacy of massage treatment technique in masseter muscle hardness: robotic experimental approach.

    PubMed

    Hiraiwa, Yuichiro; Ariji, Yoshiko; Kise, Yoshitaka; Sakuma, Shigemitsu; Kurita, Kenichi; Ariji, Eiichiro

    2013-10-01

    The study aimed to clarify the masseter muscle hardness in patients with myofascial pain, to examine their changes after massage, and to analyze whether the hardness can be an index for massage treatment. Sixteen patients with myofascial pain (12 with unilateral and 4 with bilateral masseter muscle pain) and 24 healthy volunteers were enrolled in this study. The masseter hardness between patients and the healthy volunteers was compared. The changes in the hardness in patients after massage were examined. The relation of the hardness with massage regimens and efficacies was analyzed. There was a significant right-and-left difference of the hardness in patients, although there was no difference in the healthy volunteers. The hardness decreased after massage. The pretreatment asymmetry index of the hardness showed a significant correlation with the massage pressure. It was concluded that there was a significant difference between the right and left masseter hardness in patients with myofascial pain. After massage treatment, the masseter hardness and right-and-left difference decreased. The hardness may be an index for determining the massage pressure.

  8. TRPV1 channel-mediated bilateral allodynia induced by unilateral masseter muscle inflammation in rats.

    PubMed

    Simonic-Kocijan, Suncana; Zhao, Xuehong; Liu, Wen; Wu, Yuwei; Uhac, Ivone; Wang, KeWei

    2013-12-30

    Pain in masticatory muscles is among the most prominent symptoms of temperomandibular disorders (TMDs) that have diverse and complex etiology. A common complaint of TMD is that unilateral pain of craniofacial muscle can cause a widespread of bilateral pain sensation, although the underlying mechanism remains unknown. To investigate whether unilateral inflammation of masseter muscle can cause a bilateral allodynia, we generated masseter muscle inflammation induced by unilateral injection of complete Freund's adjuvant (CFA) in rats, and measured the bilateral head withdrawal threshold at different time points using a von Frey anesthesiometer. After behavioral assessment, both right and left trigeminal ganglia (TRG) were dissected and examined for histopathology and transient receptor potential vanilloid 1 (TRPV1) mRNA expression using quantitative real-time PCR analysis. A significant increase in TRPV1 mRNA expression occurred in TRG ipsilateral to CFA injected masseter muscle, whereas no significant alteration in TRPV1 occurred in the contralateral TRG. Interestingly, central injection of TRPV1 antagonist 5-iodoresiniferatoxin into the hippocampus significantly attenuated the head withdrawal response of both CFA injected and non-CFA injected contralateral masseter muscle. Our findings show that unilateral inflammation of masseter muscle is capable of inducing bilateral allodynia in rats. Upregulation of TRPV1 at the TRG level is due to nociception caused by inflammation, whereas contralateral nocifensive behavior in masticatory muscle nociception is likely mediated by central TRPV1, pointing to the involvement of altered information processing in higher centers.

  9. [The relationships between the EMG excitation pattern of the masseter muscle and the facial skeletal morphology].

    PubMed

    Hönicke, K; Harzer, W; Eckardt, L

    1995-09-01

    The purpose of this study was to investigate the correlations between malocclusions and the electromyographic activity of the orofacial muscles as this activity reveals itself through multi-channel, simultaneous recording of surface potentials from the masseter muscle. Thirty adults with class II or class III malocclusion formed the study's patient base. Surgical correction of the anomaly was planned for all patients. Ten patients served as the control group. In addition to the standard diagnosis, EMG were recorded during various stress situations such as maximal intercuspidations, chewing, swallowing, and mandible protrusion. We obtained a so-called "myomap" by means of the simultaneous multi-channel recording of the surface potential of the right masseter. Comparison of the EMG revealed a higher activity from the masticatory muscles in the class II cases than in the class III cases. The analysis of the masseter excitation pattern brought to light interesting differences. A higher activity on the lower margin of mandible in the area of the superficial part of masseter was found in the class II cases, whereas contrary to this an increase in EMG activity was found above the deep part of masseter in class III cases. The differing distribution of excitation of the 2 parts of the muscle in class II and class III malocclusions confirms the correlation between muscle function and morphology.

  10. Changes of masseter muscle activity following injection of botulinum toxin type A in adult rats.

    PubMed

    Tsai, C Y; Lei, Y Y; Yang, L Y; Chiu, W C

    2015-11-01

    To investigate changes in masseter muscle function following intramuscular injection of different dose-dependent botulinum toxin type A (BTXA). Department of Orthodontics at Taipei Medical University. Fifty-two, 70-day-old male Wistar rats were randomly divided into four groups. Group I received 7.5 U of BTXA (0.3 ml), Group II received 5.0 U, and Group III received 2.5 U in the right masseter muscle, respectively. Group IV is the control and received no BTXA injection. A wire electrode device was implanted to record muscle activity. One week after implantation, the rats were fed every 2 h and EMG signals were recorded during the first hour. All signals were recorded for 12 weeks. Thereafter, EMG data were analyzed for statistical calculation and weights of masseter muscles were measured. Masseter muscle activity decreased 99% during the first week after BTXA injection and gradually recovered from the 3rd week on in Groups I-III. By the 12th week, muscle activity recovered to 41% in Groups I and II and 56.26% in Group III. No significant changes of muscle activity were observed in Group IV. BTXA induced a reduction in masseter muscle activity and an increased toxin dose resulted in greater depression of muscle activity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Distribution of LYVE-1 and CD31 in postnatal rat masseter muscle.

    PubMed

    Sato, Iwao; Imura, Kosuke; Miwa, Yoko; Miyado, Mami; Sunohara, Masataka

    2008-01-01

    During the development of blood vascular systems in the masseter muscle, one functional property of the blood supply via capillaries is altered by the change in feeding pattern from suckling to mastication. The lymphatic vessel hyaluronan receptor-1 (LYVE-1) is a marker of lymphatic endothelial cells. The PECAM (CD31) is also an important marker of vascular endothelial cells and lymphatic cells. The mechanisms by which circulating lymphatic endothelial cells from blood vessels in masseter muscle form a network of lymphatic capillaries and vessels functioning in jaw muscle movement remain unknown. In our results, LYVE-1- and CD31- positive reactions were located in almost identical regions at the stages examined using double immunofluorescence staining. However, the level of protein for LYVE-1 and CD31 differed between superficial and deep regions in postnatal rat masseter muscle using Western blotting analysis. The different distribution of LYVE-1 and CD31 antibody reactions was found in the deep region in contrast to that of the superficial area in 3-7-week-old rat masseter muscles. Concomitant with the increased level of protein for CD31 in the deep region, many small vessels branch in this region during development in rat masseter muscle. Therefore, different levels of protein and immunohistochemical reactions for CD31- and LYVE-1-positive cells may reflect alterations in the functional properties of the blood supply and collection via capillaries due to the changes in feeding pattern.

  12. Distribution of slow muscle fiber of muscle spindle in postnatal rat masseter muscle.

    PubMed

    Sato, Iwao; Imura, Kosuke; Miwa, Yoko; Ide, Yoshiaki; Murata, Megumi; Sunohara, Masataka

    2007-11-01

    We investigated the properties of the muscle spindle in the masseter muscle at an immunohistochemical level in rats fed for 6 weeks. Slow myosin heavy chain (MyHC) isoforms were measured and intrafusal fibers in the muscle spindle were studied to determine the relationship between the superficial and deep regions of rat masseter muscle after alternated feeding pattern. However, muscle spindles were found in both regions, mainly in the deep region of the posterior superficial region of masseter muscle. The total number of the slow fiber in the intrafusal fiber and number of muscle spindle in the deep region were high from 5 to 8 weeks old in spite of various dimensions of data such as diameter and the compositions of the intrafusal fiber. The relationship of the protein expression of slow MyHC in the two regions at 5 weeks old reversed five weeks later (10 weeks old). This period is an important stage because the mastication system in masseter muscle with muscle spindle may be changed during the alternated feeding pattern of suckling to mastication. The changes may be a marker of the feeding system and of the control by the tension receptor of muscle spindle in this stage of masseter muscle after postnatal development.

  13. The trophic effect of ciliary neurotrophic factor on injured masseter muscle in rat

    PubMed Central

    Zhang, Yujun; Wang, Xiaohui; Zhang, Mengmeng; Lin, Xuefen; Wu, Qingting; Yang, Yingying; Kong, Jingjing; Ji, Ping

    2015-01-01

    Objective(s): Occlusal trauma is one of the most common forms of oral biting dysfunction. Long-term occlusal trauma could weaken the stomatognathic system; especially damage one’s masticatory muscle. Through using the rat model, this study investigated the trophic effect of ciliary neurotrophic factor (CNTF) on injured masseter muscle. Materials and Methods: Male Wistar rats (n=36) were randomly divided into five experimental groups and one control group (6 rats per group). Animals in the experimental group were cemented modified crowns on their mandibular first molars to artificially induce occlusal trauma in 1, 3, 7, 14, and 28 days. Control group was sham-treated with forced mouth-opening for about 5 min, while no crowns were placed. After 28 days of treatment, all rats were euthanized and their masseter muscle was collected. Through immunofluorescence and real-time quantitative PCR, the expression of desmin, CNTF, and CNTFRα was investigated in rat masseter muscle. The microstructure of masseter muscle was observed by transmission electron microscope. Results: The expression of desmin showed a time-dependent decrease on traumatic and non-traumatic sides masseter, until reached the nadir at the 14th day, then restored to its normal level at the 28th day; however, the expression of CNTF and CNTFRα on the traumatic and non-traumatic sides increased from day 7, reached the peak at the 14th day, and returned to normal level on the 28th day. Conclusion: CNTF, as an important neurotrophic factor, was tightly associated to the restoring of rat injured masseter muscle, which provides new target and treatment method for clinical application. PMID:26526387

  14. Muscle spindle composition and distribution in human young masseter and biceps brachii muscles reveal early growth and maturation.

    PubMed

    Osterlund, Catharina; Liu, Jing-Xia; Thornell, Lars-Eric; Eriksson, Per-Olof

    2011-04-01

    Significant changes in extrafusal fiber type composition take place in the human masseter muscle from young age, 3-7 years, to adulthood, in parallel with jaw-face skeleton growth, changes of dentitions and improvement of jaw functions. As motor and sensory control systems of muscles are interlinked, also the intrafusal fiber population, that is, muscle spindles, should undergo age-related changes in fiber type appearance. To test this hypothesis, we examined muscle spindles in the young masseter muscle and compared the result with previous data on adult masseter spindles. Also muscle spindles in the young biceps brachii muscle were examined. The result showed that muscle spindle composition and distribution were alike in young and adult masseter. As for the adult masseter, young masseter contained exceptionally large muscle spindles, and with the highest spindle density and most complex spindles found in the deep masseter portion. Hence, contrary to our hypothesis, masseter spindles do not undergo major morphological changes between young age and adulthood. Also in the biceps, young spindles were alike adult spindles. Taken together, the results showed that human masseter and biceps muscle spindles are morphologically mature already at young age. We conclude that muscle spindles in the human young masseter and biceps precede the extrafusal fiber population in growth and maturation. This in turn suggests early reflex control and proprioceptive demands in learning and maturation of jaw motor skills. Similarly, well-developed muscle spindles in young biceps reflect early need of reflex control in learning and performing arm motor behavior. Copyright © 2011 Wiley-Liss, Inc.

  15. 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.

  16. Intraoral transposition of pedicled temporalis muscle flap followed by zygomatic implant placement.

    PubMed

    Pia, Francesco; Aluffi, Paolo; Crespi, Maria Cristina; Arcuri, Francesco; Brucoli, Matteo; Benech, Arnaldo

    2012-09-01

    Despite the recent advances of sophisticated reconstructive surgical techniques, management of maxillectomy defects continues to be challenging. For a selected group of patients, who cannot sustain a sophisticated microsurgical reconstructive procedure, a prosthetic obturator is indicated to separate the oral cavity from the sinonasal cavities. After the development of the osseointegration concept, dental implants have proven to be indicated for the rehabilitation of patients who underwent maxillectomy. Recently, surgeons can use a computer-assisted software package, which enables them to insert implants after a detailed analysis of the residual bone. For some patients with limited amount of residual maxillary bone, unusual surgical sites such as the zygomatic complex have been tested. We introduce a successful 2-step surgical procedure using a pedicled temporalis muscle flap and zygomatic implant placement to reconstruct a maxillary defect after oncological resection.

  17. Three novel antimicrobial peptides from the skin of the Indian bronzed frog Hylarana temporalis (Anura: Ranidae).

    PubMed

    Reshmy, V; Preeji, V; Parvin, A; Santhoshkumar, K; George, S

    2011-05-01

    Amphibian skin secretion is considered as a rich source of bioactive peptides. The present work describes the successful identification of three novel peptides named brevinin-1TEa, brevinin-2TEa and brevinin-2TEb present in the skin secretion of Indian bronzed frog Hylarana temporalis. The deduced open reading frame encoding the biosynthetic precursor of brevinin-1TEa consisted of 70 amino acid residues and brevinin-2TEa and brevinin-2TEb consisted of 71 and 72 amino acids, respectively. All the three peptides showed higher antimicrobial activity against Gram-negative than against Gram-positive bacteria. On the basis of the antibacterial and haemolytic activity, brevinin-2TEb is the most potent peptide reported in the present study. Further research on these peptides may provide potential clue towards newer drug development to combat various microbial diseases. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.

  18. Lengthening temporalis myoplasty and brain plasticity: a functional magnetic resonance imaging study.

    PubMed

    Garmi, R; Labbé, D; Coskun, O; Compère, J-F; Bénateau, H

    2013-08-01

    Lengthening temporalis myoplasty (LTM) is a technique developed since ten years for facial paralysis. A spontaneous smile is acquired after this surgery explains by brain plasticity and the aim of the study is to confirm this plasticity by functional magnetic resonance imaging. A functional magnetic resonance imaging (fMRI) was performed at various time points in ten patients who were operated on LTM during one year. Two different areas were found to be involved in chewing and smiling. We observed changes in the areas involved in smiling and chewing three months after surgery, and these changes persisted for at least one year. Our findings thus confirm that brain plasticity underlies the clinical observation of acquisition of a spontaneous smile. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  19. Refinements in smile reanimation: 10-year experience with the lengthening Temporalis Myoplasty.

    PubMed

    Nduka, Charles; Hallam, Marc-James; Labbe, Daniel

    2012-07-01

    The lengthening Temporalis Myoplasty (LTM) is an innovative dynamic facial reanimation procedure that has been used to great effect following its conception during the early 1990s by the senior author. Since its first description in the literature the technique has been refined and it has become clear from correspondence that certain technical aspects of the procedure require particular attention to detail. We discuss from experience of more than a hundred cases and highlight not only the important technical aspects of the procedure but also the importance of pre-operative assessment and the avoidance of complications. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Temporalis pull-through vs fascia lata augmentation in facial reanimation for facial paralysis

    PubMed Central

    Balaji, S. M.

    2016-01-01

    Objectives: Surgical rehabilitation of facial palsy is challenging as each case is unique and success rate is often unpredictable. In one technique, temporalis is elevated from origin preserving vessels, and this elevation increases the length which is tunneled into buccal tissues (pull-through technique, Group A). In the other technique, a harvested fascia lata is attached to temporalis after a coronoidectomy release and the fascia lata is attached to the modiolus (Group B). The aim of this study is to compare the two different surgical techniques. Materials and Methods: Case records of 22 cases, 15 females, and 7 males who were operated between 2008 and 2012 for facial palsy with at least 1-year follow-up, using either of the techniques were assessed for pull of muscle, postoperative pain, recovery time, motor control, and symmetry at rest. Descriptive statistics are presented. Results: The Group A (n = 7) and Group B (n = 15) formed the study group. In the Group A, residual asymmetry (n = 3), poor postoperative muscle pull (n = 2) were noticed while in the modified group it was 2 and 3, respectively. The technique used in Group B had better pull of muscle, symmetry, faster recovery time, and better motor control at 1-year follow-up than the conventional technique. Discussion and Conclusion: The difference between the two groups is due to preservation of original muscular architecture, vascular channel supply. As the muscle is not traumatized, no fibrosis occurs aiding regaining of normal function. In addition, the facial reanimation is more successful in the Group B. The mechanism and success behind the technique used in Group B is discussed elaborately in terms of localregional anatomy and physiology PMID:28299269

  1. [Study of the influence of emotion stress on mechanical hyperalgesia of masseter muscles in rats].

    PubMed

    Huang, Fei; Miao, Li; Chen, Yong-Jin; Chen, Jun

    2008-06-01

    To study the influence of emotion stress on mechanical hyperalgesia of masseter muscles in rats through the equipment of communication box. 50 Sprague-Dawley rats were randomly divided into 5 groups: Control group, emotion stress (ES) group, drug control group, saline treated control group and footshock (FS) group, 10 rats each group. Footshock group only induced emotion stress and was not concerned with the result of the experiment. The last four groups of the rats were placed in communication box and bred under the same conditions during the experiment time. According to Rens' method, von Frey filaments were used to assess the muscle mechanical threshold, head withdrawal, leg raising and crying were observed as pain action. 1) During the adaptive period of 7 days before the emotion stress experiment, mechanical pain values of bilateral masseter muscles were descent and were stabilized in the 5 th to 7 th day. In emotion stress period, hyperalgesia of emotion stress group was induced in bilateral masseter muscles, and the peak time was the 7 th day, then it alleviated in the following days and was stabilized in the 12 th to 14 th day, but its pain threshold was lower than blank control group. 2)During the emotion stress period, the change of drug control group was similar to stress group but its pain threshold was higher. It is suggested that emotion stress can lead to the hyperalgesia of masseter muscles and antidepressant drug can lower the hyperalgsia resulted of emotion stress.

  2. Oxygen saturation and electromyographic changes in masseter muscle during experimental chewing of gum with harder texture.

    PubMed

    Horikoshi, Emiko; Ishikawa, Hiroyuki; Yoshida, Tomoharu; Tamaoki, Sachio; Kajii, Takashi S

    2013-11-01

    The purpose of this study was to clarify the relationship between changes in masseter muscle oxygenation measured by near-infrared spectroscopy (NIRS) and changes in the electromyographic (EMG) power spectrum during experimental chewing of gum with harder texture, to improve the understanding of the use of NIRS in assessing masseter muscle fatigue. Ten female volunteers with normal occlusion were examined. Mean age (standard deviation) was 28.4 (3.8) years. Mean fracture stress of gum was 12.5 × 10(4) N/m(2). Subjects were instructed to chew gum for 60 s (75 strokes) on the voluntary chewing side at a pace of 1.25 strokes/s. Simultaneous recordings of NIRS and EMG signals from masseter muscle were performed during gum chewing. Oxygen saturation levels decreased from the start of chewing, then stabilized with a break point between the two phases. The normalized EMG amplitude increased and the mean frequency of the EMG power spectrum decreased during gum chewing. The timing of break point appearance was related to the timing of a significant decrease in median frequency, but no clear relationships were found between break point appearance and increased EMG amplitude. These results suggest that the break point of the oxygen saturation curve, as obtained from NIRS measurements, could be used as an indicator of masseter muscle fatigue as assessed by a shift in the EMG power spectrum to lower frequencies.

  3. Masseter Muscle Activity in Track and Field Athletes: A Pilot Study.

    PubMed

    Nukaga, Hideyuki; Takeda, Tomotaka; Nakajima, Kazunori; Narimatsu, Keishiro; Ozawa, Takamitsu; Ishigami, Keiichi; Funato, Kazuo

    2016-01-01

    Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles' activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps.

  4. Lower facial remodeling with botulinum toxin type A for the treatment of masseter hypertrophy*

    PubMed Central

    Klein, Fernanda Homem de Mello de Souza; Brenner, Fabiane Mulinari; Sato, Maurício Shigeru; Robert, Fernanda Manfron Batista Rosas; Helmer, Karin Adriane

    2014-01-01

    BACKGROUND Masseter hypertrophy has been treated with botulinum toxin injections because of esthetic complaints especially in Asians. OBJECTIVES The goal of the present study was to evaluate the efficacy of abobotulin toxin use in masseter hipertrophy treatment in Brazilians. METHODS Ten Brazilian female patients with masseter hypertrophy were subjected to injections of 90U of abobotulinum toxin A applied on each side respecting the safety zone stabilished in literature and were followed up for 24 weeks. RESULTS When analyzing the coefficients between measures of middle and lower third of the face obtained from standardized photographs, an increase was observed, with statistical significance at 2 weeks (p=0.005) and 12 weeks (p=0.001). The progression of lower third reduction was 3.94%, 5.26%, 11.99%, and 5.47% (2, 4, 12, and 24 weeks respectively). All patients showed improvement in bruxism after treatment. Observed adverse effects were masticatory fatigue, smile limitation, and smile asymmetry. CONCLUSION The use of abobotulinum toxin A for masseter hypertrophy is effective in Brazilians and reached its maximum effect of facial thinning at 12 weeks. Smile limitation had a higher incidence compared to that reported in the literature and may result from risorius muscle blockage caused by toxin dissemination. Despite its side effects, 80% of the patients would like to repeat the treatment. PMID:25387491

  5. Masseter thickness, endurance and exercise-induced pain in subjects with different vertical craniofacial morphology.

    PubMed

    Farella, Mauro; Bakke, Merete; Michelotti, Ambra; Rapuano, Alessia; Martina, Roberto

    2003-06-01

    The aim of the study was to compare neuromuscular features of the masseter muscle in subjects with different vertical craniofacial morphology. Fifteen short-faced (mandibular plane-Frankfurt plane angle < 15 degrees) and 15 normal- to long-faced (mandibular plane-Frankfurt plane angle > or = 23 degrees) male students participated. The thickness of the masseter was assessed by ultrasonography. Onset and endurance of exercise pain were recorded during sustained biting at a level of 15% of maximum voluntary contraction and 30 micro V electromyographic activity. Pain and fatigue was measured on visual analog scales before and after the biting, as well as before and after 10 min chewing. Statistical comparison showed that the masseter muscle was significantly thicker (+15%) in the short-faced than the normal- to long-faced subjects. The pain onset time and endurance time were also consistently shorter in short-faced subjects, whereas the intensity of pain and fatigue did not differ significantly between the two groups. Multiple stepwise regression showed positive influence from the mandibular plane inclination and the masseter thickness on the pain onset time and endurance time. The present findings support the concept that subjects with different craniofacial morphology show neuromuscular differences.

  6. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in healthy subjects.

    PubMed

    Miralles, R; Palazzi, C; Ormeño, G; Giannini, R; Verdugo, F; Valenzuela, S; Santander, H

    1998-04-01

    This study was conducted in order to determine the effects of body position on integrated electromyographic (IEMG) activity of sternocleidomastoid and masseter muscles in 20 healthy subjects. EMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual side of sleeping of each subject), in the following body positions: standing, seated, supine, and lateral decubitus position. Significant higher EMG activities were recorded in the sternocleidomastoid muscle in the lateral decubitus position, whereas significant lower EMG activities were recorded in the masseter muscle in the supine position. This finding supports the idea that there may exist a differential modulation of the motor neuron pools of the sternocleidomastoid and masseter muscles of peripheral and/or central origin. Significant differences in the EMG pattern as well as in the levels of EMG activities upon variations in body positions were observed between healthy subjects and patients with myogenic craniomandibular dysfunction reported by Palazzi, et al.

  7. Antero-posterior activity changes in the superficial masseter muscle after exposure to experimental pain.

    PubMed

    Türp, Jens C; Schindler, Hans J; Pritsch, Maria; Rong, Qiguo

    2002-04-01

    The aim of this randomized, controlled, double-blind study was to examine how the activation pattern of the masseter muscle changes during natural function when experimental pain is induced in a discrete anterior area of the muscle. In 20 subjects, three bipolar surface electrodes and three intramuscular fine-wire electrodes (antero-posterior mapping) were simultaneously attached above and in the right masseter muscle to record the electromyographic (EMG) activity during unilateral chewing before and after infusion of a 0.9% isotonic and 5% hypertonic saline bolus in the anterior area of the muscle. The activity of the contralateral masseter muscle was registered by surface electrodes. In addition, the development of pain intensity was quantitatively measured with a numerical rating scale (NRS). While both saline concentrations caused pain, the hypertonic solution evoked stronger pain. The experiments also provided evidence of a significant although differential activity reduction of the ipsilateral masseter muscle in the antero-posterior direction. The activity reduction decreased with increasing distance from the location of the infusion. The results support the idea that the strategy of differential activation protects the injured muscle while simultaneously maintaining optimal function.

  8. Botulinum neurotoxin type A in the masseter muscle: Effects on incisor eruption in rabbits

    PubMed Central

    Navarrete, Alfonso L.; Rafferty, Katherine L.; Liu, Zi Jun; Ye, Wenmin; Greenlee, Geoffrey M.; Herring, Susan W.

    2015-01-01

    Introduction Botulinum neurotoxins are responsible for the paralytic food poisoning, botulism. Commercial formulations such as botulinum neurotoxin type A are increasingly used for various conditions, including cosmetic recontouring of the lower face by injection of the large masseter muscles. The paralysis of a major muscle of mastication lowers occlusal force and thus might affect tooth eruption. The purpose of this study was to investigate the effects of unilateral masseter muscle injection of botulinum neurotoxin type A on the rate of eruption of incisors in a rabbit model. We hypothesized that the teeth would overerupt in an underloaded environment. Methods Forty rabbits were injected with either botulinum neurotoxin type A or saline solution in 1 masseter muscle. Mastication and muscle force production were monitored, and incisor eruption rate was assessed by caliper measurement of grooved teeth. Results The injection of saline solution had no effect. The masseter muscle injected with botulinum neurotoxin type A showed a dramatic loss of force 3 weeks after injection despite apparently normal mastication. Incisor eruption rate was significantly decreased for the botulinum neurotoxin type A group, an effect attributed to decreased attrition. Conclusions This study has implications for orthodontics. Although findings from ever-growing rabbit incisors cannot be extrapolated to human teeth, it is clear that botulinum neurotoxin type A caused a decrease in bite force that could influence dental eruption. PMID:23561411

  9. Clenching and grinding: effect on masseter and sternocleidomastoid electromyographic activity in healthy subjects.

    PubMed

    Venegas, Macarena; Valdivia, José; Fresno, María Javiera; Miralles, Rodolfo; Gutiérrez, Mario Felipe; Valenzuela, Saúl; Fuentes, Aler

    2009-07-01

    This study compares the effect of clenching and grinding on masseter and sternocleidomastoid electromyographic (EMG) activity during different jaw posture tasks in the sagittal plane. The study included 34 healthy subjects with natural dentition, Class I bilateral molar Angle relationship, and absence of posterior occlusal contacts during mandibular protrusion. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the right masseter and sternocleidomastoid muscles. EMG activity was recorded while the subjects were in standing position, during the following jaw posture tasks: A. maximal clenching in the intercuspal position; B. grinding from intercuspal position to edge-to-edge protrusive contact position; C. maximal clenching in the edge-to-edge protrusive contact position; D. grinding from edge-to-edge protrusive contact position to intercuspal position; E. grinding from retrusive contact position to intercuspal position. EMG activities in tasks B, C, D, and E were significantly lower than in task A in both muscles (mixed model with unstructured covariance matrix). EMG activity among tasks B, C, D, and E did not show significant differences in both muscles, except between tasks D and E in the masseter muscle. A higher effect was observed on the masseter than on the sternocleidomastoid muscle to avoid excessive muscular activity during clenching and grinding. The EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding.

  10. Body position effects on sternocleidomastoid and masseter EMG pattern activity in patients undergoing occlusal splint therapy.

    PubMed

    Ormeño, G; Miralles, R; Santander, H; Casassus, R; Ferrer, P; Palazzi, C; Moya, H

    1997-10-01

    This study was conducted in order to determine the effects of body position on electromyographic (EMG) activity of sternocleidomastoid and masseter muscles, in 15 patients with myogenic cranio-cervical-mandibular dysfunction undergoing occlusal splint therapy. EMG activity was recorded by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual sleeping side of each patient). EMG activity at rest and during swallowing of saliva and maximal voluntary clenching was recorded in the following body positions: standing, supine and lateral decubitus. In the sternocleidomastoid muscle significant higher EMG activities at rest and during swallowing were recorded in the lateral decubitus position, whereas during maximal voluntary clenching EMG activity did not change. In the masseter muscle significant higher EMG activity during maximal voluntary clenching in a standing position was observed, whereas EMG activity at rest and during swallowing did not change. The opposite pattern of EMG activity supports the idea that there may exist a differential modulation of the motor neuron pools of the sternocleidomastoid and masseter muscles, of peripheral and/or central origin. This suggests that the presence of parafunctional habits and body position could be closely correlated with the clinical symptomatology in these muscles in patients with myogenic craniomandibular dysfunction.

  11. Effects of experimental nasal obstruction on human masseter and suprahyoid muscle activities during sleep.

    PubMed

    Hiyama, Shigetoshi; Ono, Takashi; Ishiwata, Yasuo; Kuroda, Takayuki; Ohyama, Kimie

    2003-04-01

    The effect of nasal obstruction on nocturnal masseter and suprahyoid muscle activities using a newly developed portable electromygram (EMG)-recording unit was examined. Ten healthy Japanese males participated in this study. EMG activities of both the right masseter and bilateral suprahyoid muscles were recorded with a portable EMG-recording unit. At midnight, the subject was asked to lie on a bed after complete preparation with surface electrodes. After maximal clenching and jaw-opening effort (100% maximum voluntary contribution), the subject was allowed to fall asleep. In the first half of the night, EMG activities were recorded for about three hours of sleep without nasal obstruction. In the second half of the night, EMG activities were recorded for about three hours of sleep with nasal obstruction. In both muscles, there were no significant changes in either the maximal EMG activities or the number of events beyond 40% MVC with nasal obstruction. But in an evaluation based on the distribution of muscle activities, the EMG activity of the masseter muscle tended to decrease (P = .07) and that of the suprahyoid muscles increased significantly (P = .02) with nasal obstruction. These results suggest that nasal obstruction could modulate the activities of the masseter and suprahyoid muscles during sleep.

  12. Masseter Muscle Activity in Track and Field Athletes: A Pilot Study

    PubMed Central

    Nukaga, Hideyuki; Takeda, Tomotaka; Nakajima, Kazunori; Narimatsu, Keishiro; Ozawa, Takamitsu; Ishigami, Keiichi; Funato, Kazuo

    2016-01-01

    Teeth clenching has been shown to improve remote muscle activity (by augmentation of the Hoffmann reflex), and joint fixation (by decreased reciprocal inhibition) in the entire body. Clenching could help maintain balance, improve systemic function, and enhance safety. Teeth clenching from a sports dentistry viewpoint was thought to be important and challenging. Therefore, it is quite important to investigate mastication muscles’ activity and function during sports events for clarifying a physiological role of the mastication muscle itself and involvement of mastication muscle function in whole body movement. Running is a basic motion of a lot of sports; however, a mastication muscles activity during this motion was not clarified. Throwing and jumping operation were in a same situation. The purpose of this study was to investigate the presence or absence of masseter muscle activity during track and field events. In total, 28 track and field athletes took part in the study. The Multichannel Telemetry system was used to monitor muscle activity, and the electromyograms obtained were synchronized with digital video imaging. The masseter muscle activity threshold was set 15% of maximum voluntary clenching. As results, with few exceptions, masseter muscle activity were observed during all analyzed phases of the 5 activities, and that phases in which most participants showed masseter muscle activity were characterized by initial acceleration, such as in the short sprint, from the commencement of throwing to release in both the javelin throw and shot put, and at the take-off and landing phases in both jumps. PMID:27708727

  13. Rocuronium pharmacokinetics and pharmacodynamics in the adductor pollicis and masseter muscles.

    PubMed

    Vega, E A; Ibacache, M E; Anderson, B J; Holford, N H G; Nazar, C E; Solari, S; Allende, F A; Cortínez, L I

    2016-07-01

    The aim of this study was to characterize the dose-effect relationship of rocuronium at the adductor pollicis and masseter muscles. Ten, ASA I, adult patients, received a bolus dose of rocuronium 0.3 mg/kg during propofol based anesthesia. Train-of-four (TOF) was simultaneously monitored at the masseter and the adductor pollicis muscles until recovery. Rocuronium arterial serum concentrations were measured during 120 min. The first twitch of the TOF response was used to characterize the time-effect profile of both muscles using pharmacokinetic-pharmacodynamic analysis in NONMEM. A decrease in NONMEM objective function (∆OFV) of 3.84 points for an added parameter was considered significant at the 0.05 level. Onset time at the masseter (mean ± SD, 1.5 ± 0.9 min) was faster than at the adductor pollicis (2.7 ± 1.4 min, P < 0.05). Recovery, measured as the time to TOF ratio = 0.9 was similar between muscles 29.9 ± 6.7 (adductor pollicis) vs. 29.3 ± 8.1 (masseter). (P = 0.77). The estimated pharmacodynamic parameters [mean (95% CI)] of the adductor pollicis muscle and the masseter muscle were; plasma effect-site equilibration half-time (teq) 3.25 (2.34, 3.69) min vs. 2.86 (1.83, 3.29) min, (∆OFV 383.665); Ce50 of 1.24 (1.13, 1.56) mg/l vs. 1.19 (1.00, 1.21) mg/l, (∆OFV 184.284); Hill coefficient of 3.97 (3.82, 5.62) vs. 4.68 (3.83, 5.71), (∆OFV 78.906). We found that the masseter muscle has faster onset of blockade and similar recovery profile than adductor pollicis muscle. These findings were best, explained by a faster plasma effect-site equilibration of the masseter muscle to rocuronium. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  14. The pedicled masseter muscle transfer for smile reconstruction in facial paralysis: repositioning the origin and insertion.

    PubMed

    Matic, Damir B; Yoo, John

    2012-08-01

    The pedicled masseter muscle transfer (PMMT) is introduced as a new reconstructive option for dynamic smile restoration in patients with facial paralysis. The masseter muscle is detached from both its origin and insertion and transferred to a new position to imitate the function of the native zygomaticus major muscle. Part one of this study consisted of cadaveric dissections of 4 heads (eight sides) in order to determine whether the masseter muscle could be (a) pedicled solely by its dominant neurovascular bundle and (b) repositioned directly over the native zygomaticus major. The second part of the study consisted of clinical assessments in three patients in order to confirm the applicability of this muscle transfer. Commissure excursion and vector of contraction following PMMT were compared to the non-paralyzed side. In all eight sides, the masseter muscles were successfully isolated on their pedicle and transposed on top of and in-line with the ipsilateral zygomaticus major. The mean length of the masseter and its angle from Frankfurt's horizontal line after transposition compared favorably to the native zygomaticus major muscle. In the clinical cases, the mean commissure movements of the paralyzed and normal sides were 7 mm and 12 mm respectively. The mean angles of commissural movement for the paralyzed and normal sides were 62° and 59° respectively. The PMMT can be used as a dynamic reconstruction for patients with permanent facial paralysis. As we gain experience with the PMMT, it may be possible to use it as a first-line option for patients not eligible for free micro-neurovascular reconstruction. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  15. NGF-induced mechanical sensitization of the masseter muscle is mediated through peripheral NMDA receptors.

    PubMed

    Wong, H; Kang, I; Dong, X-D; Christidis, N; Ernberg, M; Svensson, P; Cairns, B E

    2014-06-06

    Intramuscular injection of nerve growth factor (NGF) in healthy humans mimics some of the symptoms of myofascial temporomandibular disorders (M-TMD). We hypothesized that NGF induces a prolonged myofascial mechanical sensitization by increasing peripheral N-methyl-d-aspartate (NMDA) receptor expression, leading to an enhanced response of muscle nociceptors to endogenous glutamate. Behavioral experiments with an injection of NGF (25 μg/ml, 10 μl) into the masseter muscle reduced the mechanical withdrawal threshold for 1 day in male rats and 5 days in female rats. These results mirror the sex-related differences found in NGF-induced mechanical sensitization in humans. Intramuscular injection with the competitive NMDA receptor antagonist dl-2-amino-5-phosphonovaleric acid (APV, 0.020 g/ml, 10 μl) reversed the mechanical sensitization in male but not in female rats. NGF increased the number of NMDA receptor subtype 2B (NR2B)-expressing rat trigeminal masseter ganglion neurons in both sexes, which peaked at 3 days post injection. There was an association between the levels of NR2B expression and NGF-induced mechanical sensitization. The average soma size of NR2B-expressing neurons increased significantly. Increased expression of neuropeptides (CGRP and SP) was observed in NR2B-expressing masseter ganglion neurons in female but not in male rats. In healthy men and women, comparable basal expression levels of NR2B and SP were found in peripheral fibers from masseter muscle microbiopsies. This study suggests that NGF-induced sensitization of masseter nociceptors is mediated, in part, by enhanced peripheral NMDA receptor expression. Measurement of peripheral NMDA receptor expression may be useful as a biomarker for M-TMD pain.

  16. Transcriptome analysis of trigeminal ganglia following masseter muscle inflammation in rats.

    PubMed

    Chung, Man-Kyo; Park, Jennifer; Asgar, Jamila; Ro, Jin Y

    2016-01-01

    Chronic pain in masticatory muscles is a major medical problem. Although mechanisms underlying persistent pain in masticatory muscles are not fully understood, sensitization of nociceptive primary afferents following muscle inflammation or injury contributes to muscle hyperalgesia. It is well known that craniofacial muscle injury or inflammation induces regulation of multiple genes in trigeminal ganglia, which is associated with muscle hyperalgesia. However, overall transcriptional profiles within trigeminal ganglia following masseter inflammation have not yet been determined. In the present study, we performed RNA sequencing assay in rat trigeminal ganglia to identify transcriptome profiles of genes relevant to hyperalgesia following inflammation of the rat masseter muscle. Masseter inflammation differentially regulated >3500 genes in trigeminal ganglia. Predominant biological pathways were predicted to be related with activation of resident non-neuronal cells within trigeminal ganglia or recruitment of immune cells. To focus our analysis on the genes more relevant to nociceptors, we selected genes implicated in pain mechanisms, genes enriched in small- to medium-sized sensory neurons, and genes enriched in TRPV1-lineage nociceptors. Among the 2320 candidate genes, 622 genes showed differential expression following masseter inflammation. When the analysis was limited to these candidate genes, pathways related with G protein-coupled signaling and synaptic plasticity were predicted to be enriched. Inspection of individual gene expression changes confirmed the transcriptional changes of multiple nociceptor genes associated with masseter hyperalgesia (e.g., Trpv1, Trpa1, P2rx3, Tac1, and Bdnf) and also suggested a number of novel probable contributors (e.g., Piezo2, Tmem100, and Hdac9). These findings should further advance our understanding of peripheral mechanisms involved in persistent craniofacial muscle pain conditions and provide a rational basis for identifying

  17. Dietary consistency and plasticity of masseter fiber architecture in postweaning rabbits.

    PubMed

    Taylor, Andrea B; Jones, Kelly E; Kunwar, Ravinder; Ravosa, Matthew J

    2006-10-01

    Dietary consistency has been shown to influence cross-sectional area and fiber type composition of the masticatory muscles. However, little is known about the effects of dietary consistency on masticatory muscle fiber architecture. In this study, we explore the effects of dietary consistency on the internal architecture of rabbit masseter muscle. Because activity patterns of the rabbit chewing muscles show inter- and intramuscular heterogeneity, we evaluate if alterations in fiber architecture are homogeneous across various portions of the superficial masseter muscle. We compared masseter muscle fiber architecture between two groups of weanling rabbits raised on different diets for 105 days. One group was raised on a diet of ground rabbit pellets to model underuse of the masticatory complex, while the other group was fed a diet of intact pellets and hay blocks to model an overuse diet. In all portions of the superficial masseter, physiological cross-sectional areas (PCSAs) are greater in the overuse compared to underuse diet rabbits. Thus, the mechanical demands for larger muscle and bite forces associated with early and prolonged exposure to a tough diet are met by an increase in PCSA of the superficial masseter. The larger PCSA is due entirely to increased muscle mass, as the two rabbit groups show no differences in either fiber length or angle of pinnation. Thus, increasing pinnation angle is not a necessary biomechanical solution to improving muscle and bite force during growth. The change in PCSA but not fiber length suggests that variation in dietary consistency has an impact on maximum force production but not necessarily on excursion or contraction velocity.

  18. Transcriptome analysis of trigeminal ganglia following masseter muscle inflammation in rats

    PubMed Central

    Park, Jennifer; Asgar, Jamila; Ro, Jin Y.

    2016-01-01

    Background Chronic pain in masticatory muscles is a major medical problem. Although mechanisms underlying persistent pain in masticatory muscles are not fully understood, sensitization of nociceptive primary afferents following muscle inflammation or injury contributes to muscle hyperalgesia. It is well known that craniofacial muscle injury or inflammation induces regulation of multiple genes in trigeminal ganglia, which is associated with muscle hyperalgesia. However, overall transcriptional profiles within trigeminal ganglia following masseter inflammation have not yet been determined. In the present study, we performed RNA sequencing assay in rat trigeminal ganglia to identify transcriptome profiles of genes relevant to hyperalgesia following inflammation of the rat masseter muscle. Results Masseter inflammation differentially regulated >3500 genes in trigeminal ganglia. Predominant biological pathways were predicted to be related with activation of resident non-neuronal cells within trigeminal ganglia or recruitment of immune cells. To focus our analysis on the genes more relevant to nociceptors, we selected genes implicated in pain mechanisms, genes enriched in small- to medium-sized sensory neurons, and genes enriched in TRPV1-lineage nociceptors. Among the 2320 candidate genes, 622 genes showed differential expression following masseter inflammation. When the analysis was limited to these candidate genes, pathways related with G protein-coupled signaling and synaptic plasticity were predicted to be enriched. Inspection of individual gene expression changes confirmed the transcriptional changes of multiple nociceptor genes associated with masseter hyperalgesia (e.g., Trpv1, Trpa1, P2rx3, Tac1, and Bdnf) and also suggested a number of novel probable contributors (e.g., Piezo2, Tmem100, and Hdac9). Conclusion These findings should further advance our understanding of peripheral mechanisms involved in persistent craniofacial muscle pain conditions and provide a

  19. 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.

  20. How to minimize ischemic complication related to swollen temporalis muscle following indirect revascularization surgery in moyamoya disease: a technical report.

    PubMed

    Joo, Sung Pil; Kim, Tae Sun; Moon, Hyung Sik

    2014-05-01

    There are several reports in the literature of postoperative ischemic events due to swelling of the temporalis muscle after indirect revascularization surgery. Here, we report our surgical technique for preventing ischemic events during the acute postoperative recovery period in moyamoya patients. We used various types of titanium mesh to cover the bony defect area in 8 patients (10 operations) with moyamoya disease. The mesh was cut and manipulated according to the shape of the bony defect. Surgical results were favorable, with no newly developed ischemic event or infarction in the acute recovery period. The mesh formed an outer table of skull, so there was no compressive effect on the temporalis muscle and no cosmetic defects. The titanium mesh appears to be effective and useful for prevention of ischemic insult in the treatment of moyamoya disease. The choice of this procedure depends on both the operative findings of temporalis muscle thickness and the status of ischemic vulnerability of moyamoya brain. Georg Thieme Verlag KG Stuttgart · New York.

  1. MRI displays involvement of the temporalis muscle and the deep temporal artery in patients with giant cell arteritis.

    PubMed

    Veldhoen, Simon; Klink, Thorsten; Geiger, Julia; Vaith, Peter; Glaser, Cornelia; Ness, Thomas; Duwendag, Dirk; Both, Marcus; Bley, Thorsten A

    2014-11-01

    To assess deep temporal artery and temporalis muscle involvement in patients with giant cell arteritis (GCA). Ninety-nine patients who received magnetic resonance imaging (MRI) and superficial temporal artery biopsy (TAB) were included in this study. Patients with positive TAB (n = 61) were defined as GCA patients, those with negative TAB (n = 38) as the GCA-negative reference group. Contrast-enhanced T1w-images were acquired utilizing 1.5 T and 3 T MRI. Two radiologists assessed the images. Mural contrast-hyperenhancement and wall thickening of the deep temporal artery and hyperenhancement of the muscle were defined as inflammation. MRI results were correlated with jaw claudication in 70 patients. The two observers found temporalis muscle involvement in 19.7 % (n = 12) and 21.3 % (n = 13) of GCA patients. It occurred bilaterally in 100 %. Specificities were 92/97 % and sensitivities were 20/21 %. Deep temporal artery involvement was found in 34.4 % (n = 21) and 49.2 % (n = 30) and occurred bilaterally in 80/90.5 %. Specificities were 84/95 % and sensitivities were 34/49 %. Both structures were affected simultaneously in 18/21.3 %. Jaw claudication correlated moderately with inflammation of the temporalis muscle (r = 0.31; p < 0.05) and the deep temporal artery (r = 0.38; p = 0.01). MRI visualizes changes in the temporalis muscle and the deep temporal artery in GCA. Moderate correlation of clinical symptoms with MRI results was observed. • Approximately 20 % of GCA patients presented with temporalis muscle inflammation. • A total of 34-49 % of GCA patients presented with vasculitis of the deep temporal artery. • In approximately 20 % of GCA patients, both structures were simultaneously involved. • Involvement of both structures correlated moderately with presence of jaw claudication. • MRI is a suitable tool for the assessment of vasculitis and muscle inflammation.

  2. The contribution of the deep fibers of the masseter muscle to selected tooth-clenching and chewing tasks.

    PubMed

    Belser, U C; Hannam, A G

    1986-11-01

    Anatomically, the human masseter muscle consists of at least two portions (pars superficialis, pars profunda) with distinctly different fiber directions. The purpose of this study was to describe functional behavior in the deep fibers of the masseter muscle and to define any differences in its behavior from that of the superficial fibers. In 20 subjects, EMG activity of the superficial and the deep portions of the masseter muscle was recorded during specific parafunctional (intercuspal and eccentric tooth clenching) and functional (unilateral chewing) tests. Superficial and deep activity was measured with bipolar surface electrodes and intramuscular fine-wire electrodes. Simultaneously, displacement of a lower incisor point was recorded in three dimensions. The data were collected and stored for analysis by a disk-based computer system. The results indicated that changes in the direction of effort, in mandibular position, and in the side used for chewing all influenced activity in both parts of the muscle to different extents. The most distinct separation of activity occurred when intercuspal clenching was directed retrusively; the deep fibers of the masseter muscle response reduced to 47.5% of its maximum value while that of the superficial fibers of the masseter muscle fell to 5.5%. During chewing, activity in the deep fibers of masseter muscle was distributed evenly bilaterally, whereas that in the superficial fibers of the masseter muscle was biased significantly toward the chewing side. Differentiation of activity within the masseter muscle may be relevant to the distribution of regional tenderness in the muscle when it is involved in parafunctional activity.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Alternative male mating tactics of the substrate brooding cichlid Telmatochromis temporalis in Lake Tanganyika.

    PubMed

    Katoh, Rei; Munehara, Hiroyuki; Kohda, Masanori

    2005-05-01

    Telmatochromis temporalis is a bi-parental substrate brooding cichlid endemic to Lake Tanganyika. Paired males were always larger than their mates and had territories around nests against conspecific males. However, males smaller than the paired females were found in 18% of the nests. Here we report a reproductive tactic of these small males. The small males had as heavy gonads as paired males, and the gonad somatic index (GSI) of the small males was much higher than that of the latter. The examinations of the paternity and maternity using microsatellite-DNA as a genetic marker revealed that the small males were not genetically related to the pair members, and sired some young in 3 of 5 nests. These small males did not guard the broods, suggesting that they are likely to perform reproductive parasitism as sneakers. Paired males could not enter their spawning nests due to their large size, which made it difficult to chase out sneakers once they entered the nest. Some males as small as the sneakers were found outside the territories of paired males, and their gonads were quite small. Circumstantial evidence suggests that small males have two alternative investment patterns: investing in gonad to be sneakers, and investing in growth to probably be territorial males.

  4. 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.

  5. 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.

  6. Bilateral reconstruction of smile through muscular transplants neurotized to masseter nerves.

    PubMed

    Hontanilla, Bernardo; Rodriguez-Losada, Gonzalo

    2011-05-01

    In recent years, microsurgical transplant of the gracilis muscle has been the most widely used technique in the dynamic rehabilitation of the smile. The most frequently used donor nerve is the seventh cranial nerve, as it allows for the most physiological rehabilitation, including the rehabilitation of spontaneous smile. An exception to this is the case of bilateral facial paralyses, in which there is no contralateral nerve to be used as a donor. In these cases, it is necessary to use other nerves such as the hypoglossal, the accessory nerve, or the masseter branch of the trigeminal nerve. In this article, we describe a case of dynamic bilateral facial rehabilitation with a bilateral transplant of the gracilis muscle neurotized to the masseter nerve to achieve a strong, symmetrical smile, which is properly controlled by the patient.

  7. Intramuscular Cavernous Haemangioma of Masseter Muscle – A Case Report of Surgical Excision

    PubMed Central

    Rattan, Vidya; Rai, Sachin; Kaur, Kamaljit; Gupta, Akshat

    2015-01-01

    Intramuscular haemangioma are rare benign congenital neoplasm of proliferative vascular in nature due to increased endothelial cell turnover. Less than 20% of these are found in head and neck region. The masseter muscle accounts for 5% of all intramuscular haemangioma of head and neck region. They are non metastasizing tumours which may suddenly start growing in later stages. The present article will discuss the clinical presentation, diagnostic modalities and surgical treatment of cavernous Haemangioma involving masseter muscle in a 15-year-old young female patient in whom a surgical excision of whole lesion was done under general anaesthesia and no reoccurrence of the lesion was observed after one year of follow up. PMID:26023649

  8. Effects of chewing frequency and bolus hardness on human incisor trajectory and masseter muscle activity.

    PubMed

    Bishop, B; Plesh, O; McCall, W D

    1990-01-01

    Nine adults with no orofacial dysfunctions were instructed to chew a standardized piece of soft or hard gum on the right side in time with a metronome set at 46, 100 or 160 beats/min. Jaw movements were recorded with a Myotronics kinesiograph and masseter electromyograms were detected with surface electrodes. The chewing patterns on either gum were not significantly different in any of their spatial or temporal aspects, in mean or peak opening or closing velocities, or in the timing or level of activity in either masseter at any of the three chewing frequencies. These findings suggest that during metronome-paced chewing the change in sensory feedback resulting from a change in gum hardness exerts little or no effect on either the spatial or temporal aspects of masticatory motor output.

  9. Electromyographic study of the masseter muscle in individuals with Class II malocclusion.

    PubMed

    Palomari, E T; Vitti, M; Tosello, D de Oliveira; Semprini, M; Rodrigues, A L

    2002-03-01

    The objective of this work was to study the action of the masseter muscle through electromyography and to analyze the difference of action potential generated by several pre-established jaw movements in individuals with Class II malocclusion. It was studied nine young individuals from both sexes, with ages ranging from 17 to 35, with no history of orthodontic treatment and/or having some kind of alteration in the temporomandibular joint (T.M.J.). In order to collect the electromyographic signs we have used a TECA TE-4 Electromygraph and surface electrodes type Beckman. The data were submitted to nonparametric statistical analysis by Friedman test. The response variables left occlusive contact, free protraction, protraction with occlusive contact, incisor mastication, right molar mastication and forced central occlusion movements showed significant outcomes. Thus we have concluded that as the occlusive balance suffers alterations, the malocclusions become predominant and the masseter muscle undergoes functional and structural modifications.

  10. [Electromyographic (EMG) electrode impedance and EMG activity from anterior temporal muscle and masseter muscle].

    PubMed

    Takarada, T; Alvarado Larrinaga, G; Nishida, F; Nishino, M

    1989-01-01

    The value and change with time of the impedance of surface EMG electrodes and the effects of their difference between the bipolar electrodes on the electromyographic activity from the anterior temporal muscle and the masseter muscle in six adult male subjects with normal occlusion were studied. The results were as follows: 1. In the anterior temporal muscle, if the impedance of the electrode was under 20 k omega it was stable from just after the electrode disc was applied to the skin. In the masseter muscle, if the impedance was under 30 k omega it became stable within two minutes after the electrode was applied. 2. The difference of impedance between the bipolar EMG electrodes did not correlate with EMG activity.

  11. Motor-evoked potentials in masseter muscle by electrical and magnetic stimulation in intact alert man.

    PubMed

    Macaluso, G M; Pavesi, G; Bonanini, M; Mancia, D; Gennari, P U

    1990-01-01

    The electromyographic responses of the masseter after different types of transcranial stimulation were recorded with surface and needle electrodes. Magnetic stimulation at 4 cm lateral to the vertex on the biauricular line elicited MEPs in the contralateral masseter (latency 6.9 ms) due to activation of motor cortex or adjacent elements along the cortico-nuclear pathway. The ipsilateral responses to the same stimuli and to more lateral ones had shorter latencies and were ascribed to direct stimulation of the trigeminal nerve, probably its intracisternal portion. This was also the probable origin of the ipsilateral MEPs after both anodic and cathodic bipolar electrical stimulation at 7 and 11 cm lateral to the vertex on the biauricular line.

  12. A new method for eliciting and studying H-reflexes in the human masseter.

    PubMed

    Scutter, S D; Türker, K S; Yang, J

    1997-05-01

    A non-invasive method is presented for transmuscular stimulation of the masseteric nerve, using a frame to apply a cathode to the mandibular notch and an anode to the inside of the mouth. The H-reflex response was recorded using surface, macro and single motor-unit (SMU) electromyography (EMG) from the masseter. The latency of the reflex response representing the H-reflex in SMUs was determined from the cumulative sum of the peristimulus time histogram. This latency was then corrected using a spike-trigger averaging technique, where the SMU spikes were used as triggers and the macro EMG recording as the source. SMU latencies for the H-reflex in masseter were in the range 5.9-8.8 msec, whereas H-reflex latencies for surface EMG varied between 5.4 and 6.4 msec.

  13. Entropy of Masseter Muscle Pain Sensitivity: A New Technique for Pain Assessment.

    PubMed

    Castrillon, Eduardo E; Exposto, Fernando G; Sato, Hitoshi; Tanosoto, Tomohiro; Arima, Taro; Baad-Hansen, Lene; Svensson, Peter

    2017-01-01

    To test whether manipulation of mechanical pain sensitivity (MPS) of the masseter muscle is reflected in quantitative measures of entropy. In a randomized, single-blinded, placebo-controlled design, 20 healthy volunteers had glutamate, lidocaine, and isotonic saline injected into the masseter muscle. Self-assessed pain intensity on a numeric rating scale (NRS) was evaluated up to 10 minutes following the injection, and MPS was evaluated after application (at 5 minutes and 30 minutes) of three different forces (0.5 kg, 1 kg, and 2 kg) to 15 different sites of the masseter muscle. Finally, the entropy and center of gravity (COG) of the pain sensitivity scores were calculated. Analysis of variance was used to test differences in means of tested outcomes and Tukey post hoc tests were used to adjust for multiple comparisons. The main findings were: (1) Compared with both lidocaine and isotonic saline, glutamate injections caused an increase in peak, duration, and area under the NRS pain curve (P < .01); (2) A pressure of 2 kg caused the highest NRS pain scores (P < .03) and entropy values (P < .02); (3) Glutamate injections caused increases in entropy values when assessed with 0.5 kg and 1.0 kg but not with 2.0 kg of pressure; and (4) COG coordinates revealed differences between the x coordinates for time (P < .01) and time and force for the y coordinates (P < .01). These results suggest that manipulation of MPS of the masseter muscle with painful glutamate injections can increase the diversity of MPS, which is reflected in entropy measures. Entropy allows quantification of the diversity of MPS, which may be important in clinical assessment of pain states such as myofascial temporomandibular disorders.

  14. Effect of triiodothyronine on the maxilla and masseter muscles of the rat stomatognathic system.

    PubMed

    Mariúba, M V; Goulart-Silva, F; Bordin, S; Nunes, M T

    2011-07-01

    The maxilla and masseter muscles are components of the stomatognathic system involved in chewing, which is frequently affected by physical forces such as gravity, and by dental, orthodontic and orthopedic procedures. Thyroid hormones (TH) are known to regulate the expression of genes that control bone mass and the oxidative properties of muscles; however, little is known about the effects of TH on the stomatognathic system. This study investigated this issue by evaluating: i) osteoprotegerin (OPG) and osteopontine (OPN) mRNA expression in the maxilla and ii) myoglobin (Mb) mRNA and protein expression, as well as fiber composition of the masseter. Male Wistar rats (~250 g) were divided into thyroidectomized (Tx) and sham-operated (SO) groups (N = 24/group) treated with T3 or saline (0.9%) for 15 days. Thyroidectomy increased OPG (~40%) and OPN (~75%) mRNA expression, while T3 treatment reduced OPG (~40%) and OPN (~75%) in Tx, and both (~50%) in SO rats. Masseter Mb mRNA expression and fiber type composition remained unchanged, despite the induction of hypo- and hyperthyroidism. However, Mb content was decreased in Tx rats even after T3 treatment. Since OPG and OPN are key proteins involved in the osteoclastogenesis inhibition and bone mineralization, respectively, and that Mb functions as a muscle store of O2 allowing muscles to be more resistant to fatigue, the present data indicate that TH also interfere with maxilla remodeling and the oxidative properties of the masseter, influencing the function of the stomatognathic system, which may require attention during dental, orthodontic and orthopedic procedures in patients with thyroid diseases.

  15. Measurement of the size and orientation of human masseter and medial pterygoid muscles.

    PubMed

    Hsu, C W; Shiau, Y Y; Chen, C M; Chen, K C; Liu, H M

    2001-01-01

    To gain a better understanding of biting and chewing performance, the size and orientation of the masseter and medial pterygoid muscles in living humans were studied. Twenty-seven young males having complete dentition, class I dental occlusion and normal muscle and jaw function were examined using magnetic resonance images of the head between the zygomatic arch and hyoid bone. The sections were parallel to the palatal plane, and the thickness was 3 mm without a gap. A computer software program (Medical Dental Image, MDI) was developed to identify and calculate the area of each cross section of the muscle, and the volume of the muscle was then estimated. The axis of the muscle was determined by connecting the centroids of the sections in the lower and upper 1/3 of the whole muscle. The effective muscle cross section area was then calculated by resectioning the muscle perpendicularly to the muscle axis. It was found that the mean masseter muscle volume was around 31 cm3, and that the mean medial pterygoid muscle volume was 11 cm3. Their mean effective cross section areas were around 6.2 cm2 and 3.5 cm2, respectively. The axis of the masseter muscle was more perpendicular to the palatal plane and parallel to the sagittal plane than was the medial pterygoid muscle. The results suggest that the use of magnetic resonance images (MRI) is an effective noninvasive measurement technique for determining the size and orientation of masseter and medial pterygoid muscles. This technique can be employed in future studies on human bite force evaluation and masticatory function.

  16. Jaw-opening accuracy is not affected by masseter muscle vibration in healthy men.

    PubMed

    Wiesinger, B; Häggman-Henrikson, B; Wänman, A; Lindkvist, M; Hellström, F

    2014-11-01

    There is a functional integration between the jaw and neck regions with head extension-flexion movements during jaw-opening/closing tasks. We recently reported that trigeminal nociceptive input by injection of hypertonic saline into the masseter muscle altered this integrated jaw-neck function during jaw-opening/closing tasks. Thus, in jaw-opening to a predefined position, the head-neck component increased during pain. Previous studies have indicated that muscle spindle stimulation by vibration of the masseter muscle may influence jaw movement amplitudes, but the possible effect on the integrated jaw-neck function is unknown. The aim of this study was to investigate the effect of masseter muscle vibration on jaw-head movements during a continuous jaw-opening/closing task to a target position. Sixteen healthy men performed two trials without vibration (Control) and two trials with bilateral masseter muscle vibration (Vibration). Movements of the mandible and the head were registered with a wireless three-dimensional optoelectronic recording system. Differences in jaw-opening and head movement amplitudes between Control and Vibration, as well as achievement of the predefined jaw-opening target position, were analysed with Wilcoxon's matched pairs test. No significant group effects from vibration were found for jaw or head movement amplitudes, or in the achievement of the target jaw-opening position. A covariation between the jaw and head movement amplitudes was observed. The results imply a high stability for the jaw motor system in a target jaw-opening task and that this task was achieved with the head-neck and jaw working as an integrated system.

  17. SURFACE ELECTROMYOGRAPHY OF MASSETER AND TEMPORAL MUSCLES WITH USE PERCENTAGE WHILE CHEWING ON CANDIDATES FOR GASTROPLASTY

    PubMed Central

    dos SANTOS, Andréa Cavalcante; da SILVA, Carlos Antonio Bruno

    2016-01-01

    ABSTRACT Background: Surface electromyography identifies changes in the electrical potential of the muscles during each contraction. The percentage of use is a way to treat values enabling comparison between groups. Aim: To analyze the electrical activity and the percentage of use of masseter and temporal muscles during chewing in candidates for gastric bypass. Methods: It was used Surface Electromyography Miotool 200,400 (Miotec (r), Porto Alegre/RS, Brazil) integrated with Miograph 2.0 software, involving patients between 20-40 years old. Were included data on electrical activity simultaneously and in pairs of temporal muscle groups and masseter at rest, maximum intercuspation and during the chewing of food previously classified. Results: Were enrolled 39 patients (59 women), mean age 27.1+/-5.7. The percentage of use focused on temporal muscle, in a range of 11-20, female literacy (n=11; 47.82) on the left side and 15 (65.21) on the right-hand side. In the male, nine (56.25) at left and 12 (75.00) on the right-hand side. In masseter, also in the range of 11 to 20, female literacy (n=10; 43.48) on the left side and 11 (47.83) on the right-hand side. In the male, nine (56.25) at left and eight (50.00) on the right-hand side. Conclusion: 40-50% of the sample showed electrical activity in muscles (masseter and temporal) with variable values, and after processing into percentage value, facilitating the comparison of load of used electrical activity between the group, as well as usage percentage was obtained of muscle fibers 11-20% values involving, representing a range that is considered as a reference to the group studied. The gender was not a variable. PMID:27683776

  18. Analysis of masseter muscle oxygenation and mandibular movement during experimental gum chewing with different hardness.

    PubMed

    Yoshida, Tomoharu; Ishikawa, Hiroyuki; Yoshida, Norio; Hisanaga, Yutaka

    2009-01-01

    The purpose of this study was to analyze masseter muscle oxygenation changes and mandibular movements in the experimental chewing of gums with different hardness. Subjects for this experiment comprised 23 male volunteers with normal occlusion. Mean age (SD) was 28.3 (2.2) years. Three kinds of gum with mean fracture stresses of 3.52 x 10(4) N/m(2) (Gum 1), 5.35 x 10(4) N/m(2) (Gum 2), and 14.0 x 10(4) N/m(2) (Gum 3) were used. The subjects were instructed to chew gum for 80 s (100 strokes) on the voluntary chewing side at a pace of 1.25 strokes/s. Oxygen saturation in the masseter muscle and mandibular movement during gum chewing were recorded simultaneously using near-infrared spectroscopy tissue oximetry and mandibular kinesiography. For Gum 1, no subjects showed any significant changes in oxygen saturation during gum chewing. For Gum 2, 10 subjects showed no significant changes, whereas the other 13 showed significant decreases in oxygen saturation. For Gum 3, significant decreases were seen in all subjects. Chewing motions were larger and velocity was higher in gum chewing with decreases in masseter muscle oxygen saturation compared to chewing showing no significant changes. The results suggest that the harder texture of gum enlarges chewing motion and increases chewing velocity, with an increase in the contribution of anaerobic metabolism to energy yield in masseter muscle. Differences in the responses to gum hardness may indicate individual differences in muscle fatigue tendencies when chewing harder foods.

  19. Changes in intramuscular cytokine levels during masseter inflammation in male and female rats.

    PubMed

    Niu, Katelyn Y; Ro, Jin Y

    2011-01-07

    The present study was conducted to examine cytokine profiles in the masseter muscle before and after complete Freund's adjuvant (CFA)-induced inflammation and possible sex differences in the cytokine levels. Age matched male and female Sprague Dawley rats were injected with CFA in the mid-region of the masseter muscle. Muscle tissue surrounding the injection site was extracted 6h, 1, 3 and 7 days after the injection to measure TNF-α, IL-1β, IL-6 and IL-4 levels with Luminex multi-analyte profiling (xMAP) technology. The cytokine levels were compared to those obtained from naïve rats. CFA injection into the masseter muscle led to a significant time effect in the level of TNF-α compared to that of naïve rats. The pattern of changes in TNF-α level after CFA injection was significantly different between the male and female rats owing to the differences in basal levels. CFA injection induced significant time-dependent increases in the levels of IL-1β and IL-6 in the masseter muscle in both male and female rats. The level of IL-4 was slightly, but significantly, reduced in both sexes at 6h and 3 days after CFA-induced inflammation. No significant sex differences were observed in the levels of IL-1β, IL-6 or IL-4. The results provided novel information about distinct cytokine profiles during CFA-induced muscle inflammation, and the basis for further pursuing contributions of each cytokine in pain processing and analgesic responses in both sexes. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  20. Analysis of masseter deformation patterns during a maximum exertion clenching in patients with unilateral chewing

    PubMed Central

    BUSATO, A.; BALCONI, G.; VISMARA, V.; BERTELÈ, L.; GARO, G.; DE GREGORIO, D.

    2016-01-01

    SUMMARY Purpose The aim of the following study is to examine both masseter muscles (left/right) in a group of patients suffering from unilateral chewing during a maximum exertion isometric contraction using the deformation pattern analysis of ultrasound videos and compare them with the results obtained by studying patients with alternate bilateral chewing patterns. Materials and methods This study has been conducted by use of an ultrasound machine and a linear probe which allowed us to record a video (DCM) comprised of 45 frames per second (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5–12 MHz 40 mm). The probe was fixed to a brace and the patients were asked to clench their teeth as hard as possible, obtain the muscle’s maximum exertion, for 5 seconds three times, with 30 seconds intervals in between. Both right and left masseter muscles were analyzed. We applied to the ultrasound video a dedicated software (Mudy 1.7.7.2 AMID Sulmona Italy) for the analysis of muscle deformation patterns. The total number of patients for this study is 150. Out of this number, 50 belong to Group A, mono lateral chewing on the left side arch, and 50 to Group B, mono lateral chewing on the right side arch. The remains patients belong to Group C, bilateral alternate chewing. The deformation pattern analysis of the skeletal muscles on ultrasound videos allows us to highlight with ease the clear difference in the clenching capabilities and strain management between the dominant masseter and the subordinate masseter in a unilaterally chewing patient. Results In the sample investigated both in Group A and Group B the unilateral chewing is associated with a series of parameters (number, shape, volume, position and orientation of the teeth) and is also associated with the extension of the cutting surface really available. PMID:28280533

  1. Circulating adrenaline released by sympathoadrenal activation elicits acute vasodilatation in the rat masseter muscle.

    PubMed

    Ishii, Hisayoshi; Niioka, Takeharu; Izumi, Hiroshi

    2009-05-01

    The present study was designed to examine the effects of circulating catecholamines released by sympathoadrenal system on the haemodynamics of the masseter muscle in deeply urethane-anaesthetized, artificially ventilated, cervically vagotomized and sympathectomized rats. Intravenous administration of adrenaline induced a biphasic change of blood flow in the masseter muscle (MBF). The change of blood flow showed an initial marked increase and successive slight decrease in a dose-dependent manner (0.01-1 microg/kg). The administration of noradrenaline had no significant effect on the MBF. The increase in the MBF evoked by exogenously applied adrenaline was markedly reduced by the intravenous administration of propranolol (100 microg/kg), whereas pretreatment with either hexamethonium (10 mg/kg), atropine (100 microg/kg), or phentolamine (1 mg/kg) failed to affect the MBF increase. Electrical stimulation of splanchnic nerve (SPLN) preganglionic neurones projecting to the adrenal medulla elicited frequency-dependent (1-20 Hz) increases in the MBF. The intravenous administration of the beta(2)-adrenergic receptor selective antagonist, ICI 118551 (0.5 mg/kg), almost abolished the MBF increase induced by SPLN stimulation, but pretreatment with the beta(1)-adrenergic receptor selective antagonist, atenolol (1 mg/kg), had no effect on this response. The results of the present study indicate that circulating adrenaline elicits acute vasodilatation through a beta-adrenergic mechanism in the rat masseter muscle. Vascular beta(2)-adrenergic receptors in the masseter muscle may be activated preferentially by adrenaline released from the adrenal medulla, suggesting that the sympathoadrenal system is involved in the marked MBF increase during sympathoexcitation.

  2. Differential activity patterns in the masseter muscle under simulated clenching and grinding forces.

    PubMed

    Schindler, H J; Türp, J C; Blaser, R; Lenz, J

    2005-08-01

    The aim of this study was to investigate (i) whether the masseter muscle shows differential activation under experimental conditions which simulate force generation during clenching and grinding activities; and (ii) whether there are (a) preferentially active muscle regions or (b) force directions which show enhanced muscle activation. To answer these questions, the electromyographic (EMG) activity of the right masseter muscle was recorded with five intramuscular electrodes placed in two deep muscle areas and in three surface regions. Intraoral force transfer and force measurement were achieved by a central bearing pin device equipped with three strain gauges (SG). The activity distribution in the muscle was recorded in four different mandibular positions (central, left, right, anterior). In each position, maximum voluntary contraction (MVC) was exerted in vertical, posterior, anterior, medial and lateral directions. The investigated muscle regions showed different amount of EMG activity. The relative intensity of the activation, with respect to other regions, changed depending on the task. In other words, the muscle regions demonstrated heterogeneous changes of the EMG pattern for the various motor tasks. The resultant force vectors demonstrated similar amounts in all horizontal bite directions. Protrusive force directions revealed the highest relative activation of the masseter muscle. The posterior deep muscle region seemed to be the most active compartment during the different motor tasks. The results indicate a heterogeneous activation of the masseter muscle under test conditions simulating force generation during clenching and grinding. Protrusively directed bite forces were accompanied by the highest activation in the muscle, with the posterior deep region as the most active area.

  3. 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

  4. 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

  5. A shape prior-based MRF model for 3D masseter muscle segmentation

    NASA Astrophysics Data System (ADS)

    Majeed, Tahir; Fundana, Ketut; Lüthi, Marcel; Beinemann, Jörg; Cattin, Philippe

    2012-02-01

    Medical image segmentation is generally an ill-posed problem that can only be solved by incorporating prior knowledge. The ambiguities arise due to the presence of noise, weak edges, imaging artifacts, inhomogeneous interior and adjacent anatomical structures having similar intensity profile as the target structure. In this paper we propose a novel approach to segment the masseter muscle using the graph-cut incorporating additional 3D shape priors in CT datasets, which is robust to noise; artifacts; and shape deformations. The main contribution of this paper is in translating the 3D shape knowledge into both unary and pairwise potentials of the Markov Random Field (MRF). The segmentation task is casted as a Maximum-A-Posteriori (MAP) estimation of the MRF. Graph-cut is then used to obtain the global minimum which results in the segmentation of the masseter muscle. The method is tested on 21 CT datasets of the masseter muscle, which are noisy with almost all possessing mild to severe imaging artifacts such as high-density artifacts caused by e.g. the very common dental fillings and dental implants. We show that the proposed technique produces clinically acceptable results to the challenging problem of muscle segmentation, and further provide a quantitative and qualitative comparison with other methods. We statistically show that adding additional shape prior into both unary and pairwise potentials can increase the robustness of the proposed method in noisy datasets.

  6. Muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction.

    PubMed

    Woźniak, Krzysztof; Lipski, Mariusz; Lichota, Damian; Szyszka-Sommerfeld, Liliana

    2015-01-01

    The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD). Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97) participated in this study. Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC) of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF%) revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P < 0.0000). The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction.

  7. Use of the masseter motor nerve in facial animation with free muscle transfer.

    PubMed

    Bianchi, Bernardo; Copelli, Chiara; Ferrari, Silvano; Ferri, Andrea; Sesenna, Enrico

    2012-10-01

    Facial paralysis is either congenital or acquired, and of varying severity, which leads to an asymmetrical or absent facial expression. It is an important disability both from the aesthetic and functional points of view. Between 2003 and 2008, at the Department of Maxillofacial Surgery, University of Parma, Italy, 21 patients with facial paralysis had their faces reanimated with a gracilis transplant reinnervated by the masseter motor nerve. All free-muscle transplants survived the transfer, and no flap was lost. Facial symmetry at rest and while smiling was excellent or good in most cases, and we found an appreciable improvement in both speech and oral competence. We consider that the masseter motor nerve is a powerful and reliable donor nerve, which allows us to obtain movement of the commissure and upper lip similar to those of the normal site for degree and direction. There may be a role for the masseter motor nerve in innervation of patients with facial paralysis. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  8. 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.

  9. Histological study of masseter muscle in a mouse muscular dystrophy model (mdx mouse).

    PubMed

    Abe, S; Kasahara, N; Amano, M; Yoshii, M; Watanabe, H; Ide, Y

    2000-08-01

    Histological changes in the masseter muscle were observed over time in mdx mice, a muscular dystrophy model. It was found that marked necrosis occurs about the time of weaning at around 4 weeks of age; then the tissue actively regenerates at 8 weeks and stabilizes as regenerated muscle with centronuclei at 15 weeks old. This study examined the centronucleus in regenerated muscle. The process from necrosis to regeneration in muscle fibers occurs a little later in the masseter muscle than in other limbic muscles. Regenerated muscles observed around 15 weeks after birth showed a moth-eaten appearance. Transmission Electron Microscope (TEM) observation of transverse sections of muscle fibers revealed that myofibrils surrounded lost regions in the area showing a moth-eaten appearance. Thus, some defensive mechanism may affect the ability of muscle fibers to maintain a function close to normal in mdx mice even though the muscle fibers develop muscular dystrophy. The function of the masseter muscle drastically changes from sucking to mastication behavior at around 4 weeks, and this was considered to influence the morphological changes in the muscle tissue. The moth-eaten appearance seen at 15 weeks may represent an appropriate myofibril reconstruction preventing invasion of the lost regions.

  10. Growth effects of botulinum toxin type A injected into masseter muscle on a developing rat mandible.

    PubMed

    Kim, J-Y; Kim, S-T; Cho, S-W; Jung, H-S; Park, K-T; Son, H-K

    2008-10-01

    Botulinum toxin type A (BTX-A) reduces the muscular contractions by temporarily inhibiting the release of acetylcholine at the neuromuscular junction. The purpose of this study was to investigate the effects of the BTX-A injected into the masseter muscle of a developing rat mandible. Four-week-old male (no. 80) Sprague-Dawley rats were divided into four groups: control group, saline group, BTX-A group and baseline control group. Rats of baseline group were sacrificed at 0 day to provide baseline values of the mandibular measurements. The masseter muscle of rats in the saline and the BTX-A group were administered with saline and BTX-A solutions respectively. Experimental animals were sacrificed after 4 weeks. The BTX-A group demonstrated smaller mandibular dimension compared with the other groups (P < 0.05). Their condylar cartilages showed increased apoptosis at the proliferation stage of the reserve zone and masseter muscle fibers demonstrated atrophic changes. The result demonstrated BTX-A influence on inhibitory action of the developing mandible because of apoptosis at the proliferation stage of the reserve zone of the condylar cartilage in developing rat mandible.

  11. Masseter muscles electromyography study of individuals with and without malocclusion during dental clenching.

    PubMed

    Rodrigues, K A; Ferreira, L P

    2004-01-01

    The present study had as an objective to verify the electromyographic activity of the masseter muscles during intercuspal maximal clenching in individuals with and without malocclusion. For such purpose, 37 individuals participated, constituting three distinct groups according to the classification of the occlusion: 9 individuals with clinically normal occlusion (G1), 17 individuals with Angle Class I malocclusion (G2) and 11 individuals with Angle Class II division 1 malocclusion (G3). Allparticipants were female, between the ages of 20 years, 7 months to 30 years, 8 months, with permanent natural teeth. The selection of the individuals was made with the application of a specific protocol, being complemented with an oral clinical myofunctional exam. The activity of the bilateral muscle masseter was investigated, in its superficial portion, by means of electromyographic evaluation with surface electrodes. Three consecutive intercuspal maximal clenching were recorded. The results showed that there was not significant statistical difference from the eletromyographic activity between the three groups. The conclusion was that the malocclusion did not interfere in the eletromyographic activity of the masseter muscles.

  12. Electromyographic evaluation of the masseter and temporal muscles activity in volunteers submitted to acupuncture.

    PubMed

    de Sousa, R A; Semprini, M; Vitti, M; Borsatto, M C; Hallak Regalo, S C

    2007-07-01

    To assess the effect of acupuncture on the temporal and masseter muscles activity employing surface electromyography. Thirty volunteers were evaluated according to three groups of acupuncture application: selected local points, selected points at distance and association of local and distant points. Bipolar surface electrodes were positioned bilaterally on the anterior portion of temporal muscle, as well as in the median region of masseter muscle. An electromyograph connected to a computer and a specific software registered the muscular activity before and after acupuncture, in the following experimental conditions: 1- Rest Position (RP); 2- Maximum Intercuspation Clenching (MIC); 3- Bilateral Molar Clenching with Cotton Rolls (BMCCR). The mean values obtained for the activities of the studied muscles were submitted to Analysis of Variance and Tukey complementary test. The electromyographic activity of the studied muscles was lower after the application of the methods of acupuncture in the Rest, and higher after the application of the acupuncture in the Maximum Intercuspation Clenching; the electromyographic activity of the temporal muscle was higher than the masseter muscle in the Rest and lower in the Bilateral molar clenching with cotton rolls; the electromyographic activity showed to be modified after the three used methods of acupuncture in the Maximum Intercuspation Clenching. In this clinical condition, the method of long-distance acupuncture was higher than the application of local needles and the associated method. Acupuncture provided alterations in the activity of the studied muscles, favoring conditions of rest and muscular tightness.

  13. Comparative study of excitation patterns in the masseter muscle before and after orthognathic surgery.

    PubMed

    Eckardt, L; Harzer, W; Schneevoigt, R

    1997-12-01

    This study was designed to inquire into changes occurring in the electromyographic activity throughout the masseter muscle after orthognathic surgical treatment of various bite anomalies. A total of 32 adult patients showing distinct class II (n = 15) or class III malocclusions (n = 17) were entered into the investigation. All patients had monopolar surface electromyograms of the masseter muscle taken prior to presurgical orthodontic treatment and after removal of their orthodontic appliances after surgery. Twenty eugnathic adult patients served as controls. Unlike bipolar lead readings, simultaneous sampling from 16 electrodes permits the registration of the overall excitation pattern in the entire muscle. Recordings were taken during clenching, chewing and protrusion of the lower jaw against a defined force. Comparison with preoperative EMGs proved postsurgical distribution of excitation in class 11 patients to approximate the excitation pattern of eugnathic patients. By contrast, correction in class III malocclusions produced a shift in excitation maxima in the sense of a cranial advance. Harmonization, as evident in class II patients, did not occur. The postoperative discords in masseter excitation patterns, as observed after correction of class III anomalies, are indicative of the risk of relapse and the prolonged phase of retention associated with these conditions.

  14. Muscle Fatigue in the Temporal and Masseter Muscles in Patients with Temporomandibular Dysfunction

    PubMed Central

    Woźniak, Krzysztof; Lipski, Mariusz; Lichota, Damian

    2015-01-01

    The aim of this study is to evaluate muscle fatigue in the temporal and masseter muscles in patients with temporomandibular dysfunction (TMD). Two hundred volunteers aged 19.3 to 27.8 years (mean 21.50, SD 0.97) participated in this study. Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Muscle fatigue was evaluated on the basis of a maximum effort test. The test was performed during a 10-second maximum isometric contraction (MVC) of the jaws. An analysis of changes in the mean power frequency of the two pairs of temporal and masseter muscles (MPF%) revealed significant differences in the groups of patients with varying degrees of temporomandibular disorders according to Di (P < 0.0000). The study showed an increase in the muscle fatigue of the temporal and masseter muscles correlated with the intensity of temporomandibular dysfunction symptoms in patients. The use of surface electromyography in assessing muscle fatigue is an excellent diagnostic tool for identifying patients with temporomandibular dysfunction. PMID:25883949

  15. Comparison of temporalis fascia muscle and full-thickness cartilage grafts in type 1 pediatric tympanoplasties.

    PubMed

    Yegin, Yakup; Çelik, Mustafa; Koç, Arzu Karaman; Küfeciler, Levent; Elbistanlı, Mustafa Suphi; Kayhan, Fatma Tülin

    Various graft materials have been used to close tympanic membrane perforations. In the literature, there are few studies in pediatric populations comparing different graft materials. To our knowledge, there is no reported study that measured the thickness of the tragal cartilage in pediatric tympanoplasties. The tragal cartilage is not of uniform thickness in every patient. To compare anatomical and functional outcomes of temporalis fascia muscle and full-thickness tragal cartilage in type 1 pediatric tympanoplasties. In total, 78 patients (38 males, 40 females; average age 10.02±1.98 years; range, 7-18 years) who underwent type 1 tympanoplasties in our clinic were included. Demographics, anatomical, and functional outcomes were collected. Temporalis fascia muscle and tragal cartilage were used as graft materials. Tragal cartilage was used without thinning, and the thickness of tragal cartilage was measured using a micrometer. Anatomical and functional outcomes of cartilage and fascia were compared. Audiometric results comparing the cartilage and fascia groups were conducted at 6 months, and we continued to follow the patients to 1 year after surgery. An intact graft and an air-bone gap≤20dB were regarded as a surgical success. Results with a p-value<0.05 were considered statistically significant. The graft success rate was 92.1% for the cartilage group compared with 65.0% for the temporal fascia group. In the fascia group, the preoperative air-bone gap was 33.68±11.44 dB and postoperative air-bone gap was 24.25±12.68dB. In the cartilage group, the preoperative air-bone gap was 35.68±12.94dB and postoperative air-bone gap was 26.11±12.87dB. The anatomical success rate in the cartilage group was significantly better than that for the fascia group (p<0.01). There was no statistically significant difference in functional outcomes between the fascia and cartilage groups (p>0.05). The average thickness of tragal cartilage in the pediatric population was 0.693±0

  16. Is cartilage better than temporalis muscle fascia in type I tympanoplasty? Implications for current surgical practice.

    PubMed

    Iacovou, Emily; Vlastarakos, Petros V; Papacharalampous, George; Kyrodimos, Efthymios; Nikolopoulos, Thomas P

    2013-11-01

    The aim of this study was to compare the hearing results and graft integration rates in patients undergoing myringoplasty for the reconstruction of the tympanic membrane, with the use of either cartilage or temporalis muscle fascia (TMF). A systematic literature review in Medline and other database sources up to February 2012 was carried out, and the pooled data were meta-analyzed. Twelve studies were systematically analyzed. One represented level I, one level II and ten level III evidence. The total number of treated patients was 1,286. Cartilage reconstruction was used in 536, TMF in 750 cases. Two level III studies showed a significant difference between the pre- and postoperative air-bone gap closure, in favor of cartilage grafting. The mean graft integration rate was 92.4 % in the cartilage group and 84.3 % in the TMF group (p < 0.05). The rates of re-perforations were 7.6 and 15.5 %, respectively (p < 0.05). Among the other complications of type I tympanoplasty, retraction pockets, otitis media with effusion, anterior blunting, and graft lateralization were usually surgically managed, whereas most of the rest were minor and could be dealt with conservatively. The graft integration rate in myringoplasty is higher after using cartilage, in comparison with fascia reconstructions (grade C strength of recommendation), and the rate of re-perforation is significantly lower. Although cartilage is primarily used as grafting material in cases of Eustachian tube dysfunction, adhesive otitis media, and subtotal perforation in everyday surgical practice, a wider utilization for the reconstruction of the tympanic membrane in myringoplasties can be recommended.

  17. Clinical advantages of cartilage palisades over temporalis fascia in type I tympanoplasty.

    PubMed

    Vashishth, Ashish; Mathur, Neeraj Narayan; Choudhary, Santosha Ram; Bhardwaj, Abhishek

    2014-10-01

    To compare the post-operative outcomes in using temporalis fascia and full thickness broad cartilage palisades as graft in type I tympanoplasty. This study, conducted at a tertiary referral institute, included 90 consecutive patients with mucosal type chronic otitis media requiring type I tympanoplasty with a 60/30 distribution of cases with fascia and cartilage palisades, respectively. The fascia group consisted of primary cases in adults and excluded revision cases, near-total or total perforations and pediatric cases. The cartilage group included pediatric, revision cases and near-total or total perforations. The fascia group utilized the underlay technique for grafting, whereas the cartilage group used tragal full thickness broad cartilage palisades with perichondrium attached on one side placed in an underlay or over-underlay manner. Post-operative graft take-up and hearing outcomes were evaluated after 6 months and 1 year with subjective assessment and pure tone audiometry. The graft take-up rate was 83.3% in the fascia group and 90% in the cartilage palisade group. The mean pure tone air-bone gaps pre- and post-operatively in the fascia group were 30.43 ± 5.75 dB and 17.5 ± 6.94 dB, respectively, whereas for the cartilage group, these values were 29 ± 6.21 dB and 7.33 ± 3.88 dB, respectively. Cartilage grafting with full thickness palisades is more effective than fascia as graft material, particularly in "difficult" tympanoplasties fraught with higher failure rates otherwise. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Comparison of cartilage with temporalis fascia tympanoplasty: A meta-analysis of comparative studies.

    PubMed

    Jalali, Mir Mohammad; Motasaddi, Masoud; Kouhi, Ali; Dabiri, Sasan; Soleimani, Robabeh

    2017-09-01

    To systematically review the results of type 1 tympanoplasty with temporalis fascia (TF) versus cartilage in patients with chronic otitis media (COM) for graft integration and hearing improvement. The English language literature (until June 1, 2016) was searched, using Medline (via PubMed), Scopus, ProQuest, Ovid, Cochrane database, and Google Scholar. A comprehensive review of the literature was performed. Prospective and retrospective studies enrolling patients with COM were included. Relevance and validity of selected articles were evaluated. Heterogeneity was assessed using I(2) statistics. For dichotomous variables, absolute rate differences, and number needed to treat (NNT) were calculated. For continuous variables, standard mean differences were calculated. A total of 11 prospective and 26 retrospective studies involving 3,606 patients were included. In general, the overall graft integration rates of cartilage and fascia tympanoplasty were 92% and 82%, respectively (NNT = 11.1, P < 0.001). Although there was no significant difference in the air-bone gap (ABG) closure of < 10 dB between the two groups, the subanalysis of prospective studies showed that patients in the TF group had less mean postoperative ABG (P = 0.02). Subgroup analysis of palisade grafts compared with that of TF graft revealed a significant difference in the graft integration rate favoring cartilage tympanoplasty (P = 0.01). Cartilage grafting seemed to show a higher graft integration rate compared with TF grafting. Both cartilage and fascia tympanoplasty provided similar improvements in the hearing outcome postoperatively. Large prospective trials are necessary to collect high-quality data. NA. Laryngoscope, 127:2139-2148, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  19. Efficacy of temporalis muscle transfer for correction of lagophthalmos in leprosy.

    PubMed

    Das, Premal; Kumar, Julius; Karthikeyan, G; Rao, P S S

    2011-09-01

    Temporalis Muscle Transfer (TMT) is a surgical technique used to correct lagophthalmos in leprosy patients. We have evaluated the degree of success of TMT in achieving full lid closure, which is important in preventing damage to the cornea. A retrospective study was carried out on 69 patients who had TMT done, at one centre, on 101 eyes during the period of 1998-2009. Lid gaps on direct gaze and with both gentle and forced closure, as well as voluntary muscle testing of eye lid closure, were assessed using standard measuring techniques by a qualified physiotherapist. Associated problems due to lagophthalmos were recorded both pre- and post- operatively. Data were abstracted on to a special proforma and subjected to statistical analysis using SPSS. On completion of post-operative physiotherapy, 85% of the eyes could achieve full lid closure with no measurable gap. The mean (SD) lid gap on forced closure was 48 (2.8) mm pre-operatively and 0.2 (0.5) mm at the end of the in-patient stay. The mean (SD) lid gap on gentle closure was 7.9 (2.6) mm preoperatively and 2.4 (1.8) mm post-operatively. The mean (SD) vertical inter-palpebral distance, during straight gaze, was reduced from 12.6 (1.6) pre-operatively to 9.8 (1.2) postoperatively. Exposure keratitis cleared in 16 of 27 eyes (60%) and Epiphora cleared or improved in 31 eyes. It is concluded that the TMT is a successful option (cosmetically and functionally) for correction of lagophthalmos.

  20. Modified silicone sling assisted temporalis muscle transfer in the management of lagophthalmos

    PubMed Central

    Gupta, Ramesh C; Kushwaha, Raj NS; Budhiraja, Ina; Gupta, Priyanka; Singh, Parul

    2014-01-01

    Aim: To evaluate the efficacy of modified temporalis muscle transfer (TMT) by silicone sling for the management of paralytic lagophthalmos. Settings and Design: Prospective interventional study. Materials and Methods: Ten patients of lagophthalmos due to facial palsy underwent modified TMT using silicone sling. The patients were followed-up for a period of 3 months. Palpebral aperture in primary gaze and during eye closure were assessed both pre- and postoperatively along with problems associated with lagophthalmos like exposure keratopathy and lacrimation. Statistical Analysis: Paired t-test was applied to measure the statistical outcome. Results: Eight patients achieved full correction of lagophthalmos with no lid gap on closing the eye. The mean (standard deviation (SD)) lid gap on eye closure was 7.7 (0.86) mm preoperatively, 0.5 (0.47) mm at 1st postoperative day, and 0.7 (0.75) mm at 3rd month. There was a reduction in mean lid gap on eye closure of 7 mm at 3 months (P < 0.0001) which is highly significant. The mean (SD) vertical interpalpebral distance during primary gaze was 12.05 (1.12) mm preoperatively, 10 (0.94) mm at 1st postoperative day, and 10.35 (1.08) mm at 3rd month. There was a reduction in mean vertical inter palpebral distance of 1.7 mm at 3 months (P = 0.001) which is significant. Exposure keratitis decreased in five out of six patients at 3 months. Conclusion: Modified TMT by silicone sling is a useful procedure with lesser morbidity and good outcomes for the treatment of paralytic lagophthalmos due to long standing facial palsy. PMID:24618488

  1. Modified silicone sling assisted temporalis muscle transfer in the management of lagophthalmos.

    PubMed

    Gupta, Ramesh C; Kushwaha, Raj N S; Budhiraja, Ina; Gupta, Priyanka; Singh, Parul

    2014-02-01

    To evaluate the efficacy of modified temporalis muscle transfer (TMT) by silicone sling for the management of paralytic lagophthalmos. Prospective interventional study. Ten patients of lagophthalmos due to facial palsy underwent modified TMT using silicone sling. The patients were followed-up for a period of 3 months. Palpebral aperture in primary gaze and during eye closure were assessed both pre- and postoperatively along with problems associated with lagophthalmos like exposure keratopathy and lacrimation. Paired t-test was applied to measure the statistical outcome. Eight patients achieved full correction of lagophthalmos with no lid gap on closing the eye. The mean (standard deviation (SD)) lid gap on eye closure was 7.7 (0.86) mm preoperatively, 0.5 (0.47) mm at 1 st postoperative day, and 0.7 (0.75) mm at 3 rd month. There was a reduction in mean lid gap on eye closure of 7 mm at 3 months (P < 0.0001) which is highly significant. The mean (SD) vertical interpalpebral distance during primary gaze was 12.05 (1.12) mm preoperatively, 10 (0.94) mm at 1 st postoperative day, and 10.35 (1.08) mm at 3 rd month. There was a reduction in mean vertical inter palpebral distance of 1.7 mm at 3 months (P = 0.001) which is significant. Exposure keratitis decreased in five out of six patients at 3 months. Modified TMT by silicone sling is a useful procedure with lesser morbidity and good outcomes for the treatment of paralytic lagophthalmos due to long standing facial palsy.

  2. [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.

  3. Mini-temporalis transposition: a less invasive procedure of smile restoration for long-standing incomplete facial paralysis.

    PubMed

    Chen, Gang; Yang, Xianxian; Wang, Wei; Li, Qingfeng

    2015-03-01

    Facial paralysis is a common craniofacial deformity that is responsible for significant psychological and functional impairment. Free muscle transfer in 2 stages and latissimus dorsi transfer in one stage may be the most effective surgical procedure for achieving a symmetrical spontaneous smile for a patient with complete facial paralysis. However, these 2 procedures are unsuitable for many incomplete patients. The authors introduce a less invasive procedure, termed mini-temporalis transposition that is able to achieve a symmetrical spontaneous smile in incomplete patients. Through a zigzag incision into the temporal region, the middle third of the temporalis is transferred and elongated with the palmaris longus tendon or combined with the deep temporal fascia. The strips are anchored to key points at the modiolus and the middle of the ipsilateral orbicularis oris muscle through a small intraoral incision and subcutaneous tunnel. The key points are marked during preoperative smile analysis. This procedure was applied to 15 patients with long-standing incomplete facial paralysis. All patients obtained improvements in smile symmetry after the operation, and patients' satisfaction was high. In addition, no damage to residual facial nerve functions or development of procedure-induced complications (such as a facial contour defect, lip eversion or puckering, or skin tethering) was observed in any of the patients. Nevertheless, slight temporal hollowing was observed in 4 patients, and mild bulkiness over the zygomatic arch was a common observation. In summary, the mini-temporalis transfer technique is a safe and effective method of smile restoration for long-standing incomplete facial paralysis.

  4. [Quantitative topographic characterization of the myoelectric activity distribution of the masseter muscle: mapping of spectral EMG parameters].

    PubMed

    Scholle, H C; Schumann, N P; Anders, C; Mey, E

    1992-09-01

    A new method for quantitative characterization of myoelectrical masseter activity distribution by mapping of spectral EMG-parameters is described. The surface electromyograms of M. masseter were monopolarly recorded (16 channels). On the basis of registered EMG intervals (512 ms) the spectral EMG power of several frequency bands was calculated (Fast Fourier Transformation). The spectral EMG parameters between the 16 electrode positions were estimated by linear interpolation (4-nearest neighbours algorithm). Afterwards the spectral EMG parameters were fitted in a grey-tone or colour scale with 10 intervals. The so obtained EMG activity maps ("EMG-Maps") permit a quantitative-topographic characterization of myoelectrical masseter activity during different functional load procedures. The frequency range which is to consider in masseter surface-EMG investigations encloses frequencies between 15 and 500 Hz. The topography of EMG activation pattern of M. masseter is only described in a comprehensive manner when the electrode array consists of 16 electrodes and more. During defined motor tasks like clenching with controlled forces the reproducibility of EMG-Maps which respect to the topography of EMG activity pattern is very high. The absolute values of spectral EMG power as well as power changes of selected band ranges during clenching correlate to the extent of chewing forces.

  5. Interpositional Gap Arthroplasty by Versatile Pedicled Temporalis Myofascial Flap in the Management of Temporomandibular Joint Ankylosis- A Case Series Study

    PubMed Central

    Aneja, Vikas; Bansal, Anupam; Kumawat, Vinod; Kaur, Jasleen; Shaikh, Ahemer Arif

    2016-01-01

    Temporomandibular Joint (TMJ) ankylosis is a situation in which the mandibular condyle is fused to the glenoid fossa by bone or fibrous tissue. The management of TMJ ankylosis has a complicated chore and it is challenging for the maxillofacial surgeon because of technical hitches and high rate of re-ankylosis. Interpositional gap arthroplasty is one of the modalities for its management. A range of inter-positional materials have been used to avert recurrence after gap arthroplasty in TMJ ankylosis. The aim of this series was to evaluate the effectiveness of the temporomyofacial flap in the treatment of TMJ ankylosis as an interpositional gap arthroplasty. A total of 10 cases with unilateral TMJ ankylosis were treated by interpositional gap arthroplasty by pedicled temporalis myofacial flap and evaluated with a follow-up of 6 months to 5 years (Mean 3.3 years) for the functional stability of TMJ. All the patients were successfully treated. There were no signs of recurrence in any patients up to last follow up visit. The result showed that temporalis myofascial flap is a preferable choice for inter-positional gap arthroplasty which proves its versatility as an inter-positional material. PMID:27891496

  6. Pedicle Temporalis Fascial Flap with Axial Scalp Flap Obviates Need of Free Flap in Extensive Scalp Wound

    PubMed Central

    Khainga, S. O.

    2017-01-01

    Extensive scalp defect with exposed bone is best reconstructed with flaps. Majority of these wounds are now routinely reconstructed with free flaps in many centers. Free flaps however require lengthy operative time and may not be available to all patients, where possible less extensive options should thus be encouraged. A sixty-eight-year-old patient presented to us with a Marjolin's ulcer on the vertex of the scalp. After wide local excision a defect of about 17 cm and 12 cm was left. The defect was successfully covered with a combination of an ipsilateral pedicle temporalis fascial flap and an axial supraorbital scalp flap with good outcome. In conclusion wide defects of the scalp can be fully covered with a combination of local flaps. The axial scalp flap and the pedicle temporalis fascial flap where applicable provide an easy and less demanding option in covering such wounds. These flaps are reliable with good blood supply and have got less donor side morbidity. PMID:28194294

  7. Electromyography of masticatory muscles in craniomandibular disorders.

    PubMed

    Cooper, B C; Cooper, D L; Lucente, F E

    1991-02-01

    Patients presenting to the otolaryngologist with complaints such as otalgia, dizziness, tinnitus, or fullness in the ear may be experiencing the effects of craniomandibular disorders. These disorders can involve dysfunction in the delicate interrelationship of the skull, mandible, cervical vertebrae, and neuromuscular apparatus and can present as myofacial pain. Electromyographic recordings using surface electrodes were made bilaterally on the masseter, anterior temporalis, and digastric muscles in 641 craniomandibular patients, before and after transcutaneous electrical neural stimulation, at their initial presentation and following the insertion of mandibular orthopedic appliances. In the presenting patient, muscle-resting levels significantly decreased from hyperactive levels with transcutaneous electrical neural stimulation therapy. The creation of a new occlusal position with an orthotic appliance was found to correlate with a significant reduction in otolaryngologic symptoms as well as an increase in maximum muscle activity in function and coordination of muscle groups during mandibular movement. Thus, clinical electromyographic studies are an important aid in the treatment of craniomandibular disorders.

  8. Human Masseter Muscle Fiber Type Properties, Skeletal Malocclusions, and Muscle Growth Factor Expression

    PubMed Central

    Sciote, James Joseph; Horton, Michael J.; Rowlerson, Anthea M.; Ferri, Joel; Close, John M.; Raoul, Gwenael

    2013-01-01

    Purpose We identified masseter muscle fiber type property differences in subjects with dentofacial deformities. Patients and Methods Samples of masseter muscle were collected from 139 young adults during mandibular osteotomy procedures to assess mean fiber areas and percent tissue occupancies for the 4 fiber types that comprise the muscle. Subjects were classified into 1 of 6 malocclusion groups based on the presence of a skeletal Class II or III sagittal dimension malocclusion and either a skeletal open, deep, or normal bite vertical dimension malocclusion. In a subpopulation, relative quantities of the muscle growth factors IGF-I and GDF-8 gene expression were quantified by real-time polymerase chain reaction. Results Fiber properties were not different in the sagittal malocclusion groups, but were very different in the vertical malocclusion groups (P ≤ .0004). There were significant mean fiber area differences for type II (P ≤ .0004) and type neonatal—atrial (P = .001) fiber types and for fiber percent occupancy differences for both type I–II hybrid fibers and type II fibers (P ≤ .0004). Growth factor expression differed by gender for IGF-I (P = .02) and GDF-8 (P < .01). The ratio of IGF-I:GDF-8 expression associates with type I and II mean fiber areas. Conclusion Fiber type properties are very closely associated with variations in vertical growth of the face, with statistical significance for overall comparisons at P ≤ .0004. An increase in masseter muscle type II fiber mean fiber areas and percent tissue occupancies is inversely related to increases in vertical facial dimension. PMID:21821327

  9. Changes in masseter muscle trigger points following strain-counterstrain or neuro-muscular technique.

    PubMed

    Ibáñez-García, Jordi; Alburquerque-Sendín, Francisco; Rodríguez-Blanco, Cleofás; Girao, Didac; Atienza-Meseguer, Albert; Planella-Abella, Sergi; Fernández-de-Las Peñas, César

    2009-01-01

    The aim of this study was to compare the immediate effects, on pressure pain sensitivity and active mouth opening, following the application of neuromuscular or strain/counter-strain technique in latent myofascial trigger points (MTrPs) in the masseter muscle. Seventy-one subjects, 34 men and 37 women, aged 20-65 years old, participated in this study. Subjects underwent a screening process to establish the presence of MTrPs in the masseter muscle. Subjects were divided randomly into three groups: group A which was treated with a neuromuscular intervention, group B treated with the strain/counter-strain technique, and group C as control group. Each treatment group received a weekly treatment session during 3 consecutive weeks. Outcomes measures were pressure pain thresholds (PPTs), active mouth opening and local pain (visual analogue scale, VAS) elicited by the application of 2.5kg/cm(2) of pressure over the MTrP. They were captured at baseline and 1 week after discharge by an assessor blinded to the treatment allocation of the subject. The ANOVA found a significant groupxtime interaction (F=25.3; p<0.001) for changes in PPT, changes in active mouth opening (F=10.5; p<0.001), and local pain evoked by 2.5kg/cm(2) of pressure (F=10.1; p<0.001). Within-group effect sizes were large (d>1) for PPT and mouth opening, and moderate for local pain (d<0.7, 0.5) in both intervention groups; but small (d<0.2) for the control group in all outcomes. No significant differences between both intervention groups were found for any outcome (p>0.8). Our results suggest that neuromuscular or strain/counter-strain technique might be employed in the management of latent MTrPs in the masseter muscle.

  10. Fiber-type differences in masseter muscle associated with different facial morphologies

    PubMed Central

    Rowlerson, Anthea; Raoul, Gwénaël; Daniel, Yousif; Close, John; Maurage, Claude-Alain; Ferri, Joel; Sciote, James J.

    2013-01-01

    Background The influence of muscle forces and associated physiologic behaviors on dental and skeletal development is well recognized but difficult to quantify because of the limited understanding of the interrelationships between physiologic and other mechanisms during growth. Methods The purpose of this study was to characterize fiber-type composition of masseter muscle in 44 subjects during surgical correction of malocclusion. Four fiber types were identified after immunostaining of biopsy sections with myosin heavy chain-specific antibodies, and the average fiber diameter and percentage of muscle occupancy of the fiber types were determined in each of 6 subject groups (Class II or Class III and open bite, normal bite, or deepbite). A 2 × 3 × 4 analysis of variance was used to determine significant differences between mean areas for fiber types, vertical relationships, and sagittal relationships. Results There were significant differences in percentage of occupancy of fiber types in masseter muscle in bite groups with different vertical dimensions. Type I fiber occupancy increased in open bites, and conversely, type II fiber occupancy increased in deepbites. The association between sagittal jaw relationships and mean fiber area was less strong, but, in the Class III group, the average fiber area was significantly different between the open bite, normal bite, and deepbite subjects. In the Class III subjects, type I and I/II hybrid fiber areas were greatly increased in subjects with deepbite. Conclusions Given the variation between subjects in fiber areas and fiber numbers, larger subject populations will be needed to demonstrate more significant associations between sagittal relationships and muscle composition. However, the robust influence of jaw-closing muscles on vertical dimension allowed us to conclude that vertical bite characteristics vary according to the fiber type composition of masseter muscle. PMID:15643413

  11. Conditioning of the masseter inhibitory reflex by homotopically applied painful heat in humans.

    PubMed

    Andersen, O K; Svensson, P; Ellrich, J; Arendt-Nielsen, L

    1998-12-01

    During contraction of the jaw-closing muscles, afferent input from the intraoral and perioral region can elicit two bilateral suppression periods (SP1 and SP2, respectively) in the masseter electromyogram (EMG). Non-painful electrical stimulation 2 cm from the left labial commissure was used in the present study to evoke these trigeminal inhibitory reflexes. The subjects maintained a level of 50% of their maximum masseter EMG. The degree of suppression was quantified as the percentage suppression of the mean EMG activity in a fixed post-stimulus interval (SP2, 40-90 ms). Further, brief (200 ms) painful radiant heat conditioning stimuli were delivered to the ipsilateral cheek, in order to investigate the influence of nociceptive input on the (non-nociceptive) trigeminal masseter inhibitory reflex. Nine different conditions combining radiant heat and electrical stimuli were used. Twelve stimuli were presented for each condition. The radiant heat preceded the electrical test stimuli by fixed inter-stimulus intervals (ISI), ranging from 100 ms to 500 ms. At 250-350 ms ISIs, the bilateral SP2 suppression was significantly reduced to less than 10%, in comparison to an average suppression degree of 32.5% without conditioning stimuli. The subjects perceived the heat stimulus before the electrical stimulus for a majority of the 12 pairs of stimuli at these ISIs. No differences were found in the VAS ratings for the different conditions. For the contralateral SP1, larger suppression was seen for the 300 ms ISI compared with stimulation without conditioning heat stimuli. Onset and offset for the SP1 was, however, only detected in three subjects using a criteria of 20% suppression of the pre-stimulus activity. A pre-pulse inhibitory effect onto inter-neurons in the SP2 pathways or habituation of the same inter-neurons by the heat stimuli are suggested as possible explanations for the interaction between the non-nociceptive and nociceptive input in the present study.

  12. Masseter length determines muscle spindle reflex excitability during jaw-closing movements.

    PubMed

    Naser-Ud-Din, Shazia; Sowman, Paul F; Sampson, Wayne J; Dreyer, Craig W; Türker, Kemal Sitki

    2011-04-01

    The masticatory muscles are considered to be important determinants of facial form, but little is known of the muscle spindle reflex characteristics and their relationship, if any, to face height. The aim of this study was to determine whether spindle reflexes, evoked by mechanical stimulation of an incisor and recorded on the masseter muscle, correlated with different facial patterns. Twenty-eight adult volunteers (16 women; ages, 19-38 years) underwent 2-N tap stimuli to their maxillary left central incisor during simulated mastication. Reflexes were recorded during local anesthesia of the stimulated tooth to eliminate the contribution from periodontal mechanoreceptors. Surface electromyograms of the reflex responses of the jaw muscles to these taps were recorded via bipolar electrodes on the masseter muscle and interpreted by using spike-triggered averaging of the surface electromyograms. Lateral cephalometric analysis was carried out with software (version 10.5, Dolphin, Los Angeles, Calif; and Mona Lisa, Canberra, Australia). Two-newton tooth taps produced principally excitatory reflex responses beginning at 17 ms poststimulus. Correlation analysis showed a significant relationship between these muscle spindle reflexes and facial heights: specifically, shorter face heights were associated with stronger spindle reflexes. This correlation was strongest between the derived measure of masseter length and the spindle reflex strength during jaw closure (r = -0.49, P = 0.008). These results suggest that a similar muscle spindle stimulus will generate a stronger reflex activation in the jaw muscles of patients with shorter faces compared with those with longer faces. This finding might help to explain the higher incidence of clenching or bruxism in those with short faces and also might, in the future, influence the design of orthodontic appliances and dental prostheses. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights

  13. Responses of single motor units in human masseter to transcranial magnetic stimulation of either hemisphere

    PubMed Central

    Pearce, Sophie L; Miles, Timothy S; Thompson, Philip D; Nordstrom, Michael A

    2003-01-01

    The corticobulbar inputs to single masseter motoneurons from the contra- and ipsilateral motor cortex were examined using focal transcranial magnetic stimulation (TMS) with a figure-of-eight stimulating coil. Fine-wire electrodes were inserted into the masseter muscle of six subjects, and the responses of 30 motor units were examined. All were tested with contralateral TMS, and 87 % showed a short-latency excitation in the peristimulus time histogram at 7.0 ± 0.3 ms. The response was a single peak of 1.5 ± 0.2 ms duration, consistent with monosynaptic excitation via a single D- or I1-wave volley elicited by the stimulus. Increased TMS intensity produced a higher response probability (n = 13, paired t test, P < 0.05) but did not affect response latency. Of the remaining motor units tested with contralateral TMS, 7 % did not respond at intensities tested, and 7 % had reduced firing probability without any preceding excitation. Sixteen of these motor units were also tested with ipsilateral TMS and four (25 %) showed short-latency excitation at 6.7 ± 0.6 ms, with a duration of 1.5 ± 0.3 ms. Latency and duration of excitatory peaks for these four motor units did not differ significantly with ipsilateral vs. contralateral TMS (paired t tests, P > 0.05). Of the motor units tested with ipsilateral TMS, 56 % responded with a reduced firing probability without a preceding excitation, and 19 % did not respond. These data suggest that masseter motoneurons receive monosynaptic input from the motor cortex that is asymmetrical from each hemisphere, with most low threshold motoneurons receiving short-latency excitatory input from the contralateral hemisphere only. PMID:12692177

  14. The influence of the type of contraction on the masseter muscle EMG power spectrum.

    PubMed

    Nadeau, S; Bilodeau, M; Delisle, A; Chmielewski, W; Arsenault, A B; Gravel, D

    1993-01-01

    Different behaviours of the EMG power spectrum across increasing force levels have been reported for the masseter muscle. A factor that could explain these different behaviours may be the type of contraction used, as was recently shown for certain upper limb muscles(5). The purpose of this study was to compare, between two types of isometric contractions, the behaviour of EMG power spectrum statistics (median frequency (MF) and mean power frequency (MPF)) obtained across increasing force levels. Ten women exerted, while biting in the intercuspal position, three 5 s ramp contractions that increased linearly from 0 to 100% of the maximal voluntary contraction (MVC). They also completed three step contractions (constant EMG amplitude) at each of the following levels: 20, 40, 60 and 80% MVC. EMG signals from the masseter muscle were recorded with miniature surface electrodes. The RMS, as well as the MPF and MF of the power spectrum were calculated at 20, 40, 60 and 80% MVC for each type of contraction. As expected, the RMS values showed similar increases with increasing levels of effort for both types of contractions. Different behaviours for both MPF (contraction(∗)force interaction, ANOVA, P<0.05) and MF (contraction(∗)force interaction, ANOVA, P>0.05) across increasing levels of effort were found between the two types of contraction. The use of step contractions gave rise to a decrease of both MPF and MF with increasing force, while the use of ramp contractions gave rise to an increase in both statistics up to at least 40% MVC followed by a decrease at higher force levels. These findings suggest that the type of contraction used does influence the behaviour of the spectral statistics across increasing force levels and that this could explain the differences obtained in previous studies for the masseter muscle. Copyright © 1993. Published by Elsevier Ltd.

  15. 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

  16. 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

  17. [INVESTIATION OF ELECTROMYOGRAPHIC ACTIVITY OF TEMPORAL AND MASSETER MUSCLES AFTER ORTHODONTIC TREATMENT OF MALOCCLUSION COMPLICATED BY DENTAL CROWDING].

    PubMed

    Dmitrenko, M I

    2014-01-01

    The results of investigation showed that it is necessary to use complex methods of orthodontic treatment in patients with malocclusion complicated by dental crowding. Orthodontic appliance therapy should be accompanied by differentiated massage and mioymnastics to improve functional state of masseter and temporal muscles. It was found that after the treatment electromyographic potential amplitude of temporal muscles is on the average in 1.5 times lower as compared with pretreatment records (P < 0.05). It was observed increase on the average in 1.5 times in electromyographic potential oscillation amplitude of masseter muscles during clenching after the treatment of maxillary and mandibular dental crowding (P < 0.05). Treatment of dental crowding resulted in restoration of masseter muscles functional symmetry. During clenching index MASI(MM) significantly decreased in all groups in comparison with pretreatment indices (P < 0.05).

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

    PubMed

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

    2016-04-01

    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. 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. 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. Myositis ossificans, myositis ossificans traumatica, masticatory muscles, masseter muscle, trauma.

  19. [Long-term results of two temporalis muscle transfer procedures in correction of paralytic lagophthalmos].

    PubMed

    Qian, Jiange; Yan, Liangbin; Zhang, Guocheng

    2004-11-01

    To compare the long-term results and possible complications of a modified temporalis muscle transfer (TMT) with the Johnson's procedure in correction of paralytic lagophthalmos. From September 1997 to March 2000, paralytic lagophthalmos due to leprosy in 92 patients were corrected with TMT. The 89 cases (127 to eyes including 51 unilateral and 38 bilateral) followed up 3 years after operation were analyzed. There were 69 males and 20 females with ages ranging from 18 to 65 years (52 years on average). The duration of lagophthalmos was 1-22 years with an average of 8.2 years. And 36 eyes were complicated with lower eyelid ectropion. Sixty-five eyes were corrected with Johnson's procedure (Johnson's TMT group), 62 with the modified TMT procedure (modified TMT group). The modifications were as follows: (1) omitting the fascial strip in the lower eyelid to avoid postoperative ectropion. (2) fixing the fascial strip of the upper eyelid to the middle or inner margin of the tarsal palate depending on the degree of the lagophthalmos to avoid possible ptosis of the upper eyelid. In Johnson's TMT group, the mean lid gap on light closure was reduced to 3.1 mm postoperatively from 7.7 mm preoperatively; and the mean lid gap on tight closure was reduced to 0.5 mm postoperatively from 6.1 mm preoperatively. The symptoms of redness (73.7%) and tearing (63.7%) disappeared or were improved postoperatively. However, ectropion and ptosis occurred in 24 eyes and 9 eyes respectively. The overall excellent and good rate was 58.5%. In the modified TMT group, the mean lid gap on light closure was reduced to 3.3 mm postoperatively from 7.5 mm preoperatively; and the mean lid gap on tight closure was reduced to 0. 6 mm postoperatively from 6. 3 mm preoperatively. The symptoms of redness (90.9%) and tearing (71.0%) disappeared or were improved postoperatively, and no ectropion or ptosis was found except one ectropion. The overall excellent and good rate was 87.1%, which was significantly

  20. 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

  1. Circumscribed myositis ossificans of the masseter muscle: report of a case

    PubMed Central

    PIOMBINO, P.; ORABONA, G. DELL’AVERSANA; ABBATE, V.; FINI, G.; LIBERATORE, G.M.; MICI, E.; BELLI, E.

    2013-01-01

    Summary Myositis Ossificans (MO) is an unusual pathological entity still largely unknown, characterized by dystrophic calcification leading to heterotopic ossification of intramuscular connective tissue. The masticatory muscles are exceptionally involved. Four distinct types of myositis ossificans have been described: MO Progressiva, which is a genetic disorder involving several muscular groups; MO Circumscripta, limited to a single muscle and generally due to calcification of an intramuscular haematoma following severe trauma and progressive ossification; MO Pseudo-malignant limited to soft tissue and not associated to any trauma; MO associated to paraplegia. A case of circumscribed myositis ossificans of the masseter muscle in a 62 years-old woma is reportedn. PMID:24629814

  2. Circumscribed myositis ossificans of the masseter muscle: report of a case.

    PubMed

    Piombino, P; Dell'Aversana Orabona, G; Abbate, V; Fini, G; Liberatore, G M; Mici, E; Belli, E

    2013-01-01

    Myositis Ossificans (MO) is an unusual pathological entity still largely unknown, characterized by dystrophic calcification leading to heterotopic ossification of intramuscular connective tissue. The masticatory muscles are exceptionally involved. Four distinct types of myositis ossificans have been described: MO Progressiva, which is a genetic disorder involving several muscular groups; MO Circumscripta, limited to a single muscle and generally due to calcification of an intramuscular haematoma following severe trauma and progressive ossification; MO Pseudo-malignant limited to soft tissue and not associated to any trauma; MO associated to paraplegia. A case of circumscribed myositis ossificans of the masseter muscle in a 62 years-old woman is reported.

  3. [The characteristics of masticatory muscle activity in bruxers].

    PubMed

    Li, Xue-ling; Lin, Xue-feng; Teng, Wei; Li, Shao-hua

    2008-12-01

    To evaluate the effects of bruxism on masticatory muscle electromyographic (EMG) activity. Twenty-four bruxers and sixteen asymptomatic control subjects were included through questionnaire and clinical examination. EMG activity was recorded by placing surface electrodes on bilateral anterior temporalis (TA), masseters (MM), anterior digastrics (DA) and sternocleidomastoid (SCM) muscles. EMG activities at rest, during maximal voluntary clenching in intercuspal position and swallowing were recorded by means of Bio PAK system. EMG activities of TA and MM at rest were significantly higher in bruxism group than in control group (P<0.05). When subjects clenched their teeth in intercuspal position, the activities of TA and MM were much lower in bruxism group than in control one (P<0.05). EMG activity during swallowing was no significant difference between the two groups. The asymmetry index of bilateral TA and MM in bruxism group was a little higher than the control group, but there was no significant difference between the two groups (P>0.05). Masticatory muscle dysfunction of bruxers is mainly represented as higher potential in postural position and lower potential during maximal voluntary clenching in intercuspal position of anterior temporalis and masseters.

  4. Involvement of medullary dorsal horn glial cell activation in mediation of masseter mechanical allodynia induced by experimental tooth movement.

    PubMed

    Liu, Xiao-Dong; Wang, Jing-Jie; Sun, Lei; Chen, Liang-Wei; Rao, Zhi-Ren; Duan, Li; Cao, Rong; Wang, Mei-Qing

    2009-12-01

    To investigate the involvement of microglial and astrocytic activation in the medullary dorsal horn (MDH) during the mediation of masseter area allodynia induced by experimental tooth movement (ETM). Five groups of adult Sprague-Dawley rats (n=60) were divided into control (CON), minocycline (MIN), ETM, and 10mg/kg or 30mg/kg MIN plus ETM (METM) groups. The upper-first-molar was moved mesially for rats in ETM and METM groups. Rats were pre-injected with minocycline in the MIN (30mg/kg) and METM (10mg/kg or 30mg/kg) groups. Pressure pain threshold (PPT) in masseter area was tested from day 0 to 14 for all 5 groups. Immunohistochemistry against OX42 (microglial marker) or GFAP (astrocytic maker) in the MDH was examined at days 1, 3, 7 and 14 for CON, MIN and 30mg/kg METM groups. Baseline PPT was expectedly seen in either CON or MIN groups, masseter mechanical allodynia was detected in the ETM group from day 4 to 13 (P<0.05). OX42 expression level at days 1, 3 and 7, and GFAP expression level at days 3, 7 and 14 were higher in ETM (P<0.05), but not in 30mg/kg METM, than in CON group. Minocycline reduced activation of microglia and astrocytes, and significantly attenuated the development of masseter mechanical allodynia in this model. These results indicate that mechanical allodynia in the masseter area induced by ETM can be attenuated by minocycline. Activation of microglia, possibly together with subsequent activation of astrocytes, seems to contribute to masseter mechanical allodynia.

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

    PubMed

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

    2014-01-01

    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. Investigate the association between masseter muscle tension, dental status, and physical fitness parameters. 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. 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 index, BCMI, and activities of daily living. In a

  6. 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

  7. Changes in rabbit jaw-muscle activity parameters in response to reduced masticatory load.

    PubMed

    Grünheid, T; Brugman, P; Zentner, A; Langenbach, G E J

    2010-03-01

    Mechanical food properties influence the neuromuscular activity of jaw-closing muscles during mastication. It is, however, unknown how the activity profiles of the jaw muscles are influenced by long-term alterations in masticatory load. In order to elucidate the effect of reduced masticatory load on the daily habitual activity profiles of three functionally different jaw muscles, the electromyograms of the masseter, temporalis and digastric muscles were recorded telemetrically in 16 male rabbits between seven and 20 weeks of age. Starting at eight weeks of age the experimental animals were fed significantly softer pellets than the control animals. Daily muscle activity was quantified by the relative duration of muscle use (duty time), burst number and burst length in relation to multiple activity levels. The daily duty time and burst number of the masseter muscle were significantly lower in the experimental group than in the control group at 5% and 10% of the maximum activity during the two weeks following the change in food hardness. By contrast, altered food hardness did not significantly influence the activity characteristics of the temporalis and digastric muscles. The findings suggest that a reduction in masticatory load decreases the neuromuscular activity of the jaw-closing muscles that are primarily responsible for force generation during mastication. This decrease is most pronounced in the weeks immediately following the change in food hardness and is limited to the activity levels that reflect muscle contractions during chewing. These findings support the conclusion that the masticatory system manifests few diet-specific long-term changes in the activity profiles of jaw muscles.

  8. The masticatory system under varying functional load. Part 1: Structural adaptation of rabbit jaw muscles to reduced masticatory load.

    PubMed

    Vreeke, Marloes; Langenbach, Geerling E J; Korfage, Joannes A M; Zentner, Andrej; Grünheid, Thorsten

    2011-08-01

    Skeletal muscle fibres can change their myosin heavy-chain (MyHC) isoform and cross-sectional area, which determine their contraction velocity and maximum force generation, respectively, to adapt to varying functional loads. In general, reduced muscle activity induces transition towards faster fibres and a decrease in fibre cross-sectional area. In order to investigate the effect of a reduction in masticatory load on three functionally different jaw muscles, the MyHC composition and the corresponding cross-sectional area of fibres were determined in the superficial masseter, superficial temporalis, and digastric muscles of male juvenile New Zealand White rabbits that had been raised on a soft diet (n=8) from 8 to 20 weeks of age and in those of normal diet controls (n=8). Differences between groups were tested for statistical significance using a Mann-Whitney rank sum test. The proportion and cross-sectional area of fibres co-expressing MyHC-I and MyHC-cardiac alpha were significantly smaller in the masseter muscles of the animals that had been fed soft food than in those of the controls. In contrast, the proportions and cross-sectional areas of the various fibre types in the temporalis and digastric muscles did not differ significantly between the groups. The results suggest that reducing the masticatory load during development affects the contraction velocity and maximum force generation of the jaw-closing muscles that are primarily responsible for force generation during chewing. These muscles adapt structurally to the reduced functional load with changes in the MyHC composition and cross-sectional area mainly within their slow fibre compartment.

  9. The local and referred pain from myofascial trigger points in the temporalis muscle contributes to pain profile in chronic tension-type headache.

    PubMed

    Fernández-de-Las-Peñas, César; Ge, Hong-You; Arendt-Nielsen, Lars; Cuadrado, Maria Luz; Pareja, Juan A

    2007-01-01

    To assess the local and referred pain areas and pain characteristics evoked from temporalis muscle trigger points (TrPs) in chronic tension-type headache (CTTH). Thirty CTTH patients and 30 age and sex-matched controls were studied. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history. Both temporalis muscles were examined for the presence of myofascial TrPs in a blinded fashion. The local and referred pain intensities, referred pain pattern, and pressure pain threshold were recorded. Referred pain was evoked in 87% and 54% on the dominant and nondominant sides in CTTH patients, which was significantly higher (P<0.001) than in controls (10% vs. 17%, respectively). Referred pain spread to the temple ipsilateral to the stimulated muscle in both patients and controls, with additional referral behind the eyes in most patients, but none in controls. CTTH patients reported a higher local [visual analog scale (VAS): 5.6+/-1.2 right side, 5.3+/-1.4 left side] and referred pain (VAS: 4.7+/-2 right side, 3.5+/-2.8 left side) intensity than healthy controls (VAS: 0.8+/-0.7 right side, 0.7+/-0.7 left side for local pain; and 0.3+/-0.2 right side, 0.4+/-0.3 left side for referred pain) in both temporalis muscles (both, P<0.001). The local and referred pain areas were larger in patients than in controls (P<0.001). Twenty-three out of 30 CTTH patients (77%) had active TrPs in the temporalis muscle leading to their usual headache (17 patients on the right side; 12 on the left side, whereas 6 with bilateral active TrPs). CTTH patients with active TrPs in either right or left temporalis muscle showed longer headache duration than those with latent TrPs (P=0.004). CTTH patients showed significantly (P<0.001) lower pressure pain threshold (1.1+/-0.2 right side, 1.2+/-0.3 left side) as compared with controls (2.5+/-0.5 right side, 2.6+/-0.4 left side). In CTTH patients, the evoked local and referred pain from active TrPs in the temporalis

  10. Quantitative evaluation of the tonic vibration reflex (TVR) in the masseter muscle.

    PubMed

    Takata, Y; Nakajima, T; Yamada, Y

    1996-11-01

    This study evaluated the efficacy of the tonic vibration reflex (TVR) elicited by high-frequency vibration in evaluating masticatory muscle excitability. The experiment was performed on 16 male adult volunteers, 20 to 45 years of age, without spontaneous pain or tenderness in the masticatory muscles. The subjects were seated in a chair in a fixed head position with the mouth kept open with a bite block. TVR was elicited by vibratory stimulation applied to the mandible (approximately 15 m/s2, 160 Hz). An electromyogram (EMG) was recorded bilaterally from the masseter muscles and analyzed quantitatively using an arbitrary index (TVR index) calculated from the response. Bite force was measured during clenching using a pressure-sensitive foil. Wide variations in the TVR index (maximum, 22.7%; minimum, 0.9%, average, 7.7%) were observed among individuals. The mean index for five subjects with a clenching habit was significantly higher than that for 11 subjects without a history of clenching. Tolperisone HCl (100 mg taken orally), a gamma-drive depressant, was found to reduce the response for 2 hours. There was a negative correlation (r = -.504, P < .05) between bite force and TVR index when the values on both sides were compared. The TVR may be of use in evaluating masseter muscle excitability.

  11. Action potentials and twitch forces of rabbit masseter motor units at optimum jaw angle.

    PubMed

    van Eijden, T M G J; Turkawski, S J J

    2002-08-01

    This study examines mutual correlations between electrical and contractile motor-unit properties. Action potentials and twitch force responses of 42 masseter motor units were recorded in 14 rabbits. Motor units were excited by stimulating motoneurones in the trigeminal motor nucleus. Action potentials and twitches were measured at different jaw gapes between 0 and 21 degrees, in steps of 3 degrees. For each motor unit, the jaw angle-active force interrelation was determined and variables for action potential and force were compared at the jaw angle at which the motor unit produced the largest force. The results showed a large variation in variables for action potential and force, possibly related to the variation in motor-unit morphology. A weak correlation was found between the variables for action-potential amplitude and the magnitude of optimum force, indicating that motor units producing larger forces tended to have action potentials with larger amplitudes. Twitch-contraction time and the moment arm of the motor unit correlated positively with both the median frequency and the duration of the action potential. This indicates that slower contracting motor units had longer action potentials and is in accord with the earlier observation that slower motor units are preferentially located in the anterior regions of the masseter.

  12. Age, fatigue, and excitation-contraction coupling in masseter muscles of rats.

    PubMed

    Norton, M W; Mejia, W; McCarter, R J

    2001-02-01

    The purpose of this study was to determine if masseter muscle endurance changes with increasing age and, if so, to examine mechanisms of fatigue. Characteristics of fatigue were measured under isometric conditions using high-frequency stimulation of anterior deep masseter (ADM) muscles of male Fischer 344 rats, 5 to 24 months old, and fed a hard (HD) or a soft (SD) diet. Potentiating effects of caffeine on ADM muscle performance in vitro were also examined. Fatigability increased by 48% with age in muscles of HD rats. Muscles of SD rats were highly fatigable at all ages. Increased HD fatigability was associated with significantly decreased concentrations of Na+/K+-adenosine triphosphatase (22%) and decreased responsiveness to caffeine postfatigue (29%). The pH levels decreased similarly in fatigued muscles of all groups. We conclude that the age-related increase in fatigability is associated with alterations in excitation-contraction coupling mechanisms. However, differences between SD and HD on ADM muscles represent possible fiber-type transitions.

  13. 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.

  14. Electrical activity of the anterior temporal and masseter muscles in mouth and nasal breathing children.

    PubMed

    Ferla, Aline; Silva, Ana Maria Toniolo da; Corrêa, Eliane Castilhos Rodrigues

    2008-01-01

    Mouth breathing has been associated with severe impact on the development of the stomatognathic system. This paper aims to analyze the electromyographical findings and patterns of electrical activity of the anterior temporal and masseter muscles in mouth and nasal breathing children. The patients were divided into two groups: mouth breathers (n=17) and nasal breathers (n=12). The children underwent bilateral electromyographic examination of the anterior temporal and masseter muscles at maximal intercuspal position and during usual mastication. A Myosystem Br-1 electromyograph with 12 acquisition channels, amplification with total gain of 5938, rate of acquisition of 4000 Hz, and band-pass filter of 20-1000Hz, was used in the examination. The signal was processed in Root Mean Square(RMS), measured in microV, analyzed and expressed as a normalized percentage. The data set was statistically treated with the T-test (Student). The observed level of electrical activity in the mouth breathing (MB) group was lower in all analyzed muscles, with statistical significance found only in the left temporal muscle; during mastication, mouth breathers also presented increased electrical activity on the right side and on the temporal muscle. Mouth breathing impacts the electrical activity of the muscles studied at maximal intercuspal position and during usual mastication.

  15. Motor unit activity within the depth of the masseter characterized by an adapted scanning EMG technique.

    PubMed

    van Dijk, J P; Eiglsperger, U; Hellmann, D; Giannakopoulos, N N; McGill, K C; Schindler, H J; Lapatki, B G

    2016-09-01

    To study motor unit activity in the medio-lateral extension of the masseter using an adapted scanning EMG technique that allows studying the territories of multiple motor units (MUs) in one scan. We studied the m. masseter of 10 healthy volunteers in whom two scans were performed. A monopolar scanning needle and two pairs of fine-wire electrodes were inserted into the belly of the muscle. The signals of the fine wire electrodes were decomposed into the contribution of single MUs and used as a trigger for the scanning needle. In this manner multiple MU territory scans were obtained simultaneously. We determined 161 MU territories. The maximum number of territories obtained in one scan was 15. The median territory size was 4.0mm. Larger and smaller MU territories were found throughout the muscle. The presented technique showed its feasibility in obtaining multiple MU territories in one scan. MUs were active throughout the depth of the muscle. The distribution of electrical and anatomical size of MUs substantiates the heterogeneous distribution of MUs throughout the muscle volume. This distributed activity may be of functional significance for the stabilization of the muscle during force generation. Copyright © 2016 International Federation of Clinical Neurophysiology. All rights reserved.

  16. [Muscle action potential and masticatory rhythm of anterior temporal and masseter muscles in children and adults].

    PubMed

    Alvarado Larrinaga, G; Takarada, T; Nishida, F; Nishino, M

    1989-01-01

    For the investigation of the functional change of the masticatory muscles along with growth and development, electromyographic evaluation was carried out. The subjects were 6 children (5 males and 1 female) with full deciduous dentition (Hellman's dental age IIA) aged 4.5 +/- 0.2 years and 6 adults (4 males and 2 females) with full permanent dentition aged 27.7 +/- 3.8 years. EMG signals were recorded bilaterally by means of bipolar silver surface electrodes from the anterior temporal and masseter muscles when the subjects were chewing chewing gum or performing maximum clenches in intercuspal position. The cumulative power values from 62.5 to 1000 Hz in the EMG power spectrum during chewing or clenching were calculated as the muscle action potential. The ratio of the action potential of each muscle to the total action potential of four muscles were analyzed. Masticatory rhythm during chewing was analyzed by means of the time parameter (duration, interval and cycle) and their coefficients of variation. The results were as follows: 1. In children the temporal muscles predominated in chewing and clenching, whereas in adults there were three types with Temporal muscles predominating, Masseter muscles predominating and both muscles sharing equally. 2. No statistically significant differences between children and adults were observed in the duration, interval and cycle. 3. In adults the coefficients of variation of the duration, interval and cycle were smaller and the masticatory rhythm was more stable than in children.

  17. [Motor unit activities of human masseter muscle during sustained voluntary contractions].

    PubMed

    Shimizu, T

    1990-02-01

    The purpose of this paper is to investigate the motor unit activities of the human masseter muscle during sustained the bite force at a constant level. The electrical activities recorded with surface and inserted electrodes were studied, with the following results. 1. The masseter muscle had the changes of activities in two phases as a contraction progressed. 2. In the first phase, surface EMG activities decreased and discharge frequency of motor units also decreased. 3. In the second phase, surface EMG activities increased and discharge frequency of motor units also increased. 4. In the first phase, it was suggested that the bite force was maintained by an increase in the twitch tension produced by a motor unit and that there were no recruitment of additional motor units. 5. In the second phase, it was indicated that the bite force was maintained by the recruitment of new motor units and an increase in the discharge frequency of motor units to compensate a loss of force resulted from the contractile element fatigue.

  18. Characterization and morphological comparison of human dura mater, temporalis fascia, and pericranium for the correct selection of an autograft in duraplasty procedures.

    PubMed

    Morales-Avalos, Rodolfo; Soto-Domínguez, Adolfo; García-Juárez, Jaime; Saucedo-Cardenas, Odila; Bonilla-Galvan, José R; Cardenas-Serna, Marcela; Guzmán-López, Santos; Elizondo-Omaña, Rodrigo E

    2017-01-01

    The objective of this study was to characterize and compare the morphological characteristics of the dura mater, the pericranium, and the temporal fascia to ascertain the most adequate tissue to use as a dura graft. 20 dura mater, 20 pericranium and 20 temporalis fascia samples were analyzed. Each of the samples was stained with hematoxylin and eosin, orcein, Van Gieson, Masson's trichrome and Verhoeff-Van Gieson (600 slides in total) for a general morphological evaluation, as well as a quantitative, morphometric and densitometric analysis of elastic fibers present in each of the tissues. The micro-densitometric analysis of the tissues indicated that the area occupied by the elastic fibers showed values of 1.766 ± 1.376, 4.580 ± 3.041, and 8.253 ± 4.467 % for the dura mater, the temporalis fascia and the pericranium, respectively (p < 0.05, all pairs). The values observed in the analysis of the density intensity were 3.42E+06 ± 2.57E+06, 1.41E+07 ± 1.28E+07, and 1.63E+07 ± 9.19E+06 for the dura mater, the temporalis fascia and the pericranium, respectively (p < 0.05), dura mater vs. temporalis fascia and dura mater vs. pericranium). This is the first study to compare the dura mater with tissues for dural autograft and to quantify the elastic component present in these tissues. The results indicate that the temporalis fascia is a better dural graft because of its intrinsic tissue properties.

  19. 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

  20. [Changes of productions of energy metabolism in masseter of rats induced by occlusal interference].

    PubMed

    Xu, X X; Cao, Y; Fu, K Y; Xie, Q F

    2017-02-18

    To investigate the effect of occlusal interference on the energy metabolism of masticatory muscle by studying the changes of adenosine triphosphate (ATP), adenosine diphosphate (ADP), inosine monophosphate (IMP), phosphocreatine, creatine, lactate and pH level in masseter muscles of rats after occlusal interference. Fifty male Sprague-Dawley rats were randomly assigned into experimental group (n=40) and control group (n=10). In experimental group, 0.4 mm thick metal crown was cemented to the upper right first molar of the rat, and maintained for 3, 7, 10, 14 d separately (n=10 for each time point). No occlusal interference was applied for control group. Bilateral masseter muscles of all the rats were acquired under general anesthesia. The samples of 5 rats in each group were fully homogenized with 0.4 mol/L perchlorate (10 mL/g). The homogenates were centrifuged, filtered and analyzed for ATP, ADP, IMP, phosphocreatine, creatine and lactate content by high performance liquid chromatography. The other samples in each group were mixed with homogenates containing 5 mmol/L sodium iodoacetate (10 mL/g), then homogenized and measured for pH value by pH meter in thermostatic water bathunder 37 degrees centigrade. Compared with control group, ATP content in bilateral masseter of the rats increased 3 d after occlusal interference [right side:(5.36±0.13) μmol/g,left side:(5.77±0.25) μmol/g] (P<0.05), and back to normal on 7, 10 and 14 d. There was an increase in IMP [right side:(0.21±0.03) μmol/g,left side:(0.19±0.03) μmol/g]and creatine content [right side:(24.76±2.94) μmol/g,left side:(27.75±2.23) μmol/g]in bilateral masseter of the rats 7 d after occlusal interference (P<0.05) and no difference was detected on 3, 10, and 14. Phosphocreatine content in bilateral masseter started to decline 7 d after occlusal interference and maintained the low level on 10 and 14 d [right side:(10.70±0.71) μmol/g, (11.57±0.52) μmol/g, (10.74±1.39) μmol/g, left side:(10.05

  1. Shear-wave sonoelastography for assessing masseter muscle hardness in comparison with strain sonoelastography: study with phantoms and healthy volunteers.

    PubMed

    Ariji, Yoshiko; Nakayama, Miwa; Nishiyama, Wataru; Nozawa, Michihito; Ariji, Eiichiro

    2016-01-01

    Objectives Shear-wave sonoelastography is expected to facilitate low operator dependency, high reproducibility and quantitative evaluation, whereas there are few reports on available normative values of in vivo tissue in head and neck fields. The purpose of this study was to examine the reliabilities on measuring hardness using shear-wave sonoelastography and to clarify normal values of masseter muscle hardness in healthy volunteers. Methods Phantoms with known hardness ranging from 20 to 140 kPa were scanned with shear-wave sonoelastography, and inter- and intraoperator reliabilities were examined compared with strain sonoelastography. The relationships between the actual and measured hardness were analyzed. The masseter muscle hardness in 30 healthy volunteers was measured using shear-wave sonoelastography. The inter- and intraoperator intraclass correlation coefficients were almost perfect. Strong correlations were seen between the actual and measured hardness. The mean hardness of the masseter muscles in healthy volunteers was 42.82 ± 5.56 kPa at rest and 53.36 ± 8.46 kPa during jaw clenching. The hardness measured with shear-wave sonoelastography showed high-level reliability. Shear-wave sonoelastography may be suitable for evaluation of the masseter muscles.

  2. Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography.

    PubMed

    Nakayama, M; Ariji, Y; Nishiyama, W; Ariji, E

    2015-01-01

    To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers. Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter- and intraexaminer agreement. Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching. The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching.

  3. Evaluation of the masseter muscle elasticity with the use of acoustic coupling agents as references in strain sonoelastography

    PubMed Central

    Ariji, Y; Nishiyama, W; Ariji, E

    2015-01-01

    Objectives: To verify the use of a single coupling agent as a reference to obtain the elasticity index (EI) ratios and to investigate the EI ratios of the masseter muscles of healthy volunteers. Methods: Muscle phantoms with known elasticity (20, 40 and 60 kPa in the Young's modulus) were examined by strain-type sonoelastography using a coupling agent as the reference. Eight examiners tested soft (with 7 kPa) and hard (with 40 kpa) reference coupling agents separately. The correlation coefficients were determined between the EI ratio and Young's modulus of muscle phantoms. The interclass correlation coefficients were calculated for inter- and intraexaminer agreement. Results: Strong correlations were found between the EI ratios and Young's modulus for both soft and hard references. The variations of the EI ratios were larger with soft coupling agents than those with hard coupling agents, and they increased in phantoms with 60 kPa elasticity. There were no differences in the EI ratios of the masseter muscle at rest between males and females or between the right and left sides. The ratio increased during clenching. Conclusions: The hard reference coupling agent was suitable for obtaining EI ratio of the masseter muscle. No differences were found in the EI ratios of the masseter muscle either between sexes or between the right and left sides at rest, and the ratios increased with the widening of their variations during clenching. PMID:25411712

  4. Shear-wave sonoelastography for assessing masseter muscle hardness in comparison with strain sonoelastography: study with phantoms and healthy volunteers

    PubMed Central

    Nakayama, Miwa; Nishiyama, Wataru; Nozawa, Michihito

    2016-01-01

    Objectives Shear-wave sonoelastography is expected to facilitate low operator dependency, high reproducibility and quantitative evaluation, whereas there are few reports on available normative values of in vivo tissue in head and neck fields. The purpose of this study was to examine the reliabilities on measuring hardness using shear-wave sonoelastography and to clarify normal values of masseter muscle hardness in healthy volunteers. Methods Phantoms with known hardness ranging from 20 to 140 kPa were scanned with shear-wave sonoelastography, and inter- and intraoperator reliabilities were examined compared with strain sonoelastography. The relationships between the actual and measured hardness were analyzed. The masseter muscle hardness in 30 healthy volunteers was measured using shear-wave sonoelastography. Results: The inter- and intraoperator intraclass correlation coefficients were almost perfect. Strong correlations were seen between the actual and measured hardness. The mean hardness of the masseter muscles in healthy volunteers was 42.82 ± 5.56 kPa at rest and 53.36 ± 8.46 kPa during jaw clenching. Conclusions: The hardness measured with shear-wave sonoelastography showed high-level reliability. Shear-wave sonoelastography may be suitable for evaluation of the masseter muscles. PMID:26624000

  5. 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.

  6. Temporal profile and amplitude of human masseter muscle activity is adapted to food properties during individual chewing cycles.

    PubMed

    Grigoriadis, A; Johansson, R S; Trulsson, M

    2014-05-01

    Jaw actions adapt to the changing properties of food that occur during a masticatory sequence. In the present study, we investigated how the time-varying activation profile of the masseter muscle changes during natural chewing in humans and how food hardness affects the profile. We recorded surface electromyography (EMG) of the masseter muscle together with the movement of the lower jaw in 14 healthy young adults (mean age 22) when chewing gelatin-based model food of two different hardness. The muscle activity and the jaw kinematics were analysed for different phases of the chewing cycles. The increase in the excitatory drive of the masseter muscle was biphasic during the jaw-closing phase showing early and late components. The transition between these components occurred approximately at the time of tooth-food contact. During the masticatory sequence, when the food was particularised, the size of the early component as well as the peak amplitude of the EMG significantly decreased along with a reduction in the duration of the jaw-closing phase. Except for amplitude scaling, food hardness did not appreciably affect the muscle's activation profile. In conclusion, when chewing food during natural conditions, masseter muscle activation adapted throughout the masticatory sequence, principally during the jaw-closing phase and influenced both early and late muscle activation components. Furthermore, the adaptation of jaw actions to food hardness was affected by amplitude scaling of the magnitude of the muscle activity throughout the masticatory sequence. © 2014 John Wiley & Sons Ltd.

  7. Temporomandibular joint-evoked responses by spinomedullary neurons and masseter muscle are enhanced after repeated psychophysical stress

    PubMed Central

    Okamoto, Keiichiro; Tashiro, Akimasa; Chang, Zheng; Thompson, Randall; Bereiter, David A.

    2012-01-01

    Psychological stress is a risk factor to develop musculoskeletal pain of the head and neck; however, the basis for this relationship remains uncertain. This study tested the hypothesis that psychophysical stress alone was sufficient to alter the encoding properties of spinomedullary dorsal horn neurons and masseter muscle activity in male rats. Repeated forced swim conditioning increased markedly both the background firing rate and temporomandibular joint (TMJ)-evoked activity of neurons in deep dorsal horn, while neurons in superficial laminae were less affected. Stress also increased the responses to stimulation of facial skin overlying the TMJ of neurons in deep and superficial dorsal horn. TMJ-evoked masseter muscle activity was enhanced significantly in stressed rats, an effect that was reduced by prior blockade of the spinomedullary junction region. These data indicated that repeated psychophysical stress induced widespread effects on the properties of medullary dorsal horn neurons and masseter muscle activity. The effects of stress were seen preferentially on neurons in deep dorsal horn and included enhanced responses to chemosensory input from the TMJ and mechanical input from overlying facial skin. The stress-induced elevation in TMJ-evoked masseter muscle activity matched well the changes seen in dorsal horn neurons. It is concluded that the spinomedullary junction region plays a critical role in the integration of psychophysical stress and sensory information relevant for nociception involving deep craniofacial tissues. PMID:22519876

  8. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in patients with myogenic cranio-cervical-mandibular dysfunction.

    PubMed

    Palazzi, C; Miralles, R; Soto, M A; Santander, H; Zuñiga, C; Moya, H

    1996-07-01

    This study was conducted in order to determine the effects of body position on integrated electromyographic (IEMG) activity of sternocleidomastoid and masseter muscles in 17 patients with myogenic cranio-cervical-mandibular dysfunction. EMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual side of sleeping of each patient), in the following body positions: standing, seated, supine, and lateral decubitus position. Significant higher EMG activities were recorded in the sternocleidomastoid muscle in the lateral decubitus position and in the supine position (except during swallowing), whereas a significant higher EMG activity was recorded in the masseter muscle during maximal voluntary clenching in standing and seated positions. The EMG pattern observed suggests that the presence of parafunctional habits and body position could be closely correlated with the clinical symptomatology in the sternocleidomastoid and masseter muscles at wakening and during waking hours, respectively, in patients with myogenic cranio-cervical-mandibular dysfunction.

  9. The temporalis muscle flap for reconstruction of soft palate and lateral oropharyngeal wall after transoral robotic surgery.

    PubMed

    Meccariello, Giuseppe; Montevecchi, Filippo; Deganello, Alberto; D'Agostino, Giovanni; Bellini, Chiara; Zeccardo, Ermelinda; Vicini, Claudio

    2016-12-20

    Trans Oral robotic surgery (TORS) is a prominent surgical approach for the resection of oropharyngeal tumors without division of the lip and mandible. The current practice following TORS is to allow the defect to heal by secondary intention, but some defects following TORS are large and complex enough to benefit soft-tissue coverage. In the free flap era, regional flaps are often overlooked albeit they still represent a valid alternative. In terms of cost-effectiveness, the use of alternative pedicled flaps in TORS framework probably reduced the risks of postoperative complications, with consequent expenditure restraints and reducing treatment costs arising from operating room duration and double surgical team. In this report we described the successfully use of the pedicled temporalis muscle flap for the reconstruction of the soft palate and lateral pharyngeal wall following TORS. This versatile and reliable flap may be a valid option in TORS framework. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Three-dimensional CT might be a potential evaluation modality in correction of asymmetrical masseter muscle hypertrophy by botulinum toxin injection.

    PubMed

    No, Yeon A; Ahn, Byeong Heon; Kim, Beom Joon; Kim, Myeung Nam; Hong, Chang Kwon

    2016-01-01

    For correction of this asymmetrical hypertrophy, botulinum toxin type A (BTxA) injection is one of convenient treatment modalities. Unfortunately, physical examination of masseter muscle is not enough to estimate the exact volume of muscle hypertrophy difference. Two Koreans, male and female, of bilateral masseter hypertrophy with asymmetricity were evaluated. BTxA (NABOTA(®), Daewoong, Co. Ltd., Seoul, Korea) was injected at master muscle site with total 50 U (25 U at each side) and volume change was evaluated with three-dimensional (3D) CT image analysis. Maximum reduction of masseter hypertrophy was recognized at 2-month follow-up and reduced muscle size started to restore after 3 months. Mean reduction of masseter muscle volume was 36% compared with baseline. More hypertrophied side of masseter muscle presented 42% of volume reduction at 2-month follow-up but less hypertrophied side of masseter muscle showed 30% of volume shrinkage. In conclusion, 3D CT image analysis might be the exact evaluation tool for correction of asymmetrical masseter hypertrophy by botulinum toxin injection.

  11. 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.

  12. Smile Reanimation after Unilateral Facial Palsy by Lengthening Temporalis Myoplasty: Objective and Subjective Evaluation on 25 Cases.

    PubMed

    Foirest, Claire; Granger, Benjamin; Gatignol, Peggy; Bernat, Isabelle; Nguyen, Yann; Lamas, Georges; Tankere, Frederic

    2017-04-01

    Comparison of functional results of lengthening temporalis myoplasty relies in current practice on subjective scales. The goal of this study was to define a simple, reproducible, objective scale validated through a comparison with a subjective scale for smile symmetrization results after temporal muscle myoplasty. A retrospective study was conducted on 25 patients having a unilateral facial palsy and rehabilitated with lengthening temporalis myoplasty. Evaluation consisted of objective measures: smile horizontal symmetry between left and right sides, vertical symmetry, and smile width on healthy and paretic sides on preoperative and postoperative photographs. Subjective scales were also used (i.e., a numeric scale and the Terzis and Noah scale) by a jury (four professionals and four nonprofessionals) and the patient himself or herself. Each evaluation was performed in three conditions: at rest, at intermediary smile, and at maximum smile. Comparison of objective measures on the impaired side showed a postoperative improvement in the three conditions evaluation. Reproducibility of the numeric scale was weak for evaluation at rest and fair for maximum smile evaluation (intraclass correlation coefficient of 0.57). The Terzis and Noah scale was not reproducible from one observer to another. At maximum smile, a correlation between smile symmetry in the vertical plane, smile symmetry in the horizontal plane, and professional evaluation with the numeric scale on the one hand and global patient satisfaction on the other hand was observed. Postoperative smile horizontal symmetry between left and right sides, and smile vertical symmetry, are good indicators with which to assess postoperative results of facial palsy rehabilitation.

  13. Autophagic-lysosomal pathway functions in the masseter and tongue muscles in the klotho mouse, a mouse model for aging.

    PubMed

    Iida, Ryo-hei; Kanko, Syuhei; Suga, Takeo; Morito, Mitsuhiko; Yamane, Akira

    2011-02-01

    Klotho mutant (kl/kl) mice, a type of short-lived mouse models, display several aging-related phenotypes. To investigate whether the atrophy of skeletal muscles is induced in these mice via activation of the ubiquitin-proteasomal pathway and/or the autophagic-lysosomal pathway through an alteration of insulin/IGF-I signaling, we analyzed the activity of the two pathways for protein degradation and components of the insulin/IGF signaling pathway in their skeletal muscles. The masseter, tongue, and gastrocnemius muscles in kl/kl showed marked reductions in muscle weight and in myofiber diameter compared with +/+. The autophagic-lysosomal pathway in kl/kl was activated in the masseter and tongue, but not in the gastrocnemius, compared with that in +/+, whereas the ubiquitin-proteasomal pathway in these three muscles of kl/kl was not altered. No marked difference in the phosphorylation levels of insulin/IGF-I signaling components, such as insulin/IGF-I receptor, Akt, and FoxO in three muscles studied were found between kl/kl and +/+, but the phosphorylation levels of signaling component at the downstream of mTOR such as 4E-BP1 and p70 S6K were suppressed in the masseter and tongue of kl/kl compared with +/+. Deficiency of essential amino acids is reported to activate the autophagy-lysosomal pathway through the down-regulation of mTOR, not through IGF-Akt-FoxO. The masseter and tongue seem to be more actively moved than limb muscles in kl/kl, because they are essential for survival activities such as mastication, swallowing, and respiration. Thus, the deficiency of amino acid by the active movement of the masseter and tongue seems to stimulate the autophagic-lysosomal pathway via the down-regulation of mTOR signalling pathway.

  14. The postoperative trismus, nerve injury and secondary angle formation after partial masseter muscle resection combined with mandibular angle reduction: a case report

    PubMed Central

    2017-01-01

    A patient, who underwent partial masseter muscle resection and mandibular angle reduction at a plastic surgery clinic, visited this hospital with major complaints of trismus and dysesthesia. A secondary angle formation due to a wrong surgical method was observed via clinical and radiological examinations, and the patient complained of trismus due to the postoperative scars and muscular atrophy caused by the masseter muscle resection. The need for a masseter muscle resection in square jaw patients must be approached with caution. In addition, surgical techniques must be carefully selected in order to prevent complications, and obtain effective and satisfactory surgery results. PMID:28280710

  15. Multiple active myofascial trigger points and pressure pain sensitivity maps in the temporalis muscle are related in women with chronic tension type headache.

    PubMed

    Fernández-de-las-Peñas, César; Caminero, Ana B; Madeleine, Pascal; Guillem-Mesado, Amparo; Ge, Hong-You; Arendt-Nielsen, Lars; Pareja, Juan A

    2009-01-01

    To describe the common locations of active trigger points (TrPs) in the temporalis muscle and their referred pain patterns in chronic tension type headache (CTTH), and to determine if pressure sensitivity maps of this muscle can be used to describe the spatial distribution of active TrPs. Forty women with CTTH were included. An electronic pressure algometer was used to assess pressure pain thresholds (PPT) from 9 points over each temporalis muscle: 3 points in the anterior, medial and posterior part, respectively. Both muscles were examined for the presence of active TrPs over each of the 9 points. The referred pain pattern of each active TrP was assessed. Two-way analysis of variance detected significant differences in mean PPT levels between the measurement points (F=30.3; P<0.001), but not between sides (F=2.1; P=0.2). PPT scores decreased from the posterior to the anterior column (P<0.001). No differences were found in the number of active TrPs (F=0.3; P=0.9) between the dominant side the nondominant side. Significant differences were found in the distribution of the active TrPs (chi2=12.2; P<0.001): active TrPs were mostly found in the anterior column and in the middle of the muscle belly. The analysis of variance did not detect significant differences in the referred pain pattern between active TrPs (F=1.1, P=0.4). The topographical pressure pain sensitivity maps showed the distinct distribution of the TrPs indicated by locations with low PPTs. Multiple active TrPs in the temporalis muscle were found, particularly in the anterior column and in the middle of the muscle belly. Bilateral posterior to anterior decreased distribution of PPTs in the temporalis muscle in women with CTTH was found. The locations of active TrPs in the temporalis muscle corresponded well to the muscle areas with lower PPT, supporting the relationship between multiple active muscle TrPs and topographical pressure sensitivity maps in the temporalis muscle in women with CTTH.

  16. Nocturnal electromyographic evaluation of masseter muscle activity in the complete denture patient.

    PubMed

    von Gonten, A S; Palik, J F; Oberlander, B A; Rugh, J D

    1986-11-01

    Nocturnal oral activity was evaluated in 12 complete denture wearers by means of EMG measurements of the masseter muscle. Patients who had worn dentures for at least 6 months were selected. EMG levels were compared when subjects slept with and without the dentures in the mouth. Three subjects appeared to have reduced EMG values when sleeping with the dentures. However, no overall group trends or significant differences were obtained. High variability in nightly EMG values could not be explained by a post hoc analysis of patient oral symptoms or denture characteristics. Efforts should be directed at improved methodology to study the specific mechanism of the effect of denture wearing on nocturnal muscle activity levels. Additional knowledge is needed on the occurrence and effects of parafunctional habits in the edentulous patients.

  17. Proliferative myositis of the masseter muscle. A case report and a review of the literature.

    PubMed

    Orlowski, W; Freedman, P D; Lumerman, H

    1983-09-01

    A case of proliferative myositis of the masseter muscle in a 62-year-old woman is presented and pertinent literature is reviewed. This benign pseudosarcomatous proliferative lesion has not been previously reported in any of the muscles of mastication. Clinically the patient presented with pain and difficulty in opening of the mouth. On initial examination, a malignant salivary gland tumor was suspected. The proliferative myositis exhibits a disturbing microscopic appearance characterized by the presence of numerous hyperchromatic fibroblasts and oval or spindle-shaped giant cells which resemble malignant rhabdomyoblasts. These lesions have been often misdiagnosed as rhabdomyosarcoma and other types of sarcomas. Awareness of the microscopic characteristics of proliferative myositis and the possibility of its occurrence in the perioral soft tissues is important in avoiding misdiagnosis of this benign condition.

  18. Surface electromyographic evaluation of the asymptomatic human masseter muscle with turns and amplitude analysis.

    PubMed

    Kashima, K; Rahman, O I; Sakoda, S; Shiba, R

    2000-04-01

    Electromyographic turns, or reversals of direction, per second (TS) and mean amplitude per turn (AT) are variables that have been widely used to assist and support an electrodiagnosis in neuromuscular disorders. The purpose of this study was to explore the feasibility of utilizing the TS and AT in conjunction with surface electrodes as a method for assessing masticatory muscle function. Ten normal subjects were instructed to exert brief isometric contractions at various levels, and the TS and AT were calculated from the surface electromyographic signals of the masseter muscle. Our results showed that the AT increased with contraction at all contraction levels, demonstrating a linear relationship, while the TS showed a nonlinear increase characterized by an initial steep rise followed by a plateau, which was simulated with a third polynomial function. It is considered that the TS and AT may provide valuable physiological information about the underlying mechanisms of recruitment and the firing of motor units.

  19. EMG power spectrum patterns of anterior temporal and masseter muscles in children and adults.

    PubMed

    Yuen, S W; Hwang, J C; Poon, P W

    1989-05-01

    The power spectrum of electromyograms (EMG) has been demonstrated to vary with muscles having different muscle fiber type compositions. This study investigated the variations in EMG power spectrum patterns of the masticatory muscles with age and gender by comparison of the mean power frequency (MPF) of the anterior temporal and masseter muscles in children and adults. Surface EMG signals were sampled bilaterally from the muscles when the subjects were performing maximum voluntary isometric clenches at maximal intercuspal position. The results indicated that MPF values were age-dependent (p less than 0.001), and sexual dimorphism was evident (p less than 0.001), with lower MPF values in male and adult muscles. While male adults had the lowest and female children had the highest MPF values, female adults had MPF values closer to values obtained from male children. These differences or similarities could be attributed to the degree of differentiation of the muscles during growth and development of the craniofacial morphology.

  20. The role of masseter muscle EMG during DISE to predict the effectiveness of MAD: preliminary results.

    PubMed

    Marchese, M R; Scarano, E; Rizzotto, G; Grippaudo, C; Paludetti, G

    2016-12-01

    The use of a mandibular advancement device (MAD) increases the activity of the temporo-mandibular (TM) complex and masseter (MM) muscles with the risk of reducing treatment compliance. Predictors of treatment outcome are of importance in selecting patients who might benefit from MAD without side effects. The role of mandibular advancement (MA) during drug-induced sleep endoscopy (DISE) is controversial. In three cases (BMI < 30) affected by non-severe OSAS (AHI < 30 e/h), we recorded the surface EMG signal of MM activity during DISE. At follow-up all cases improved the AHI, two cases that showed transient increase of MM activity did not suffer from changes of overjet and did not complain of discomfort with the use of MAD. The case that showed a continuing increase of MM activity reported TM discomfort without changes of dental occlusion. EMG of MM during DISE may contribute to ameliorate the selection of cases amenable to treatment with MAD.

  1. Cold pressor stimulus temperature and resting masseter muscle haemodynamics in normal humans.

    PubMed

    Maekawa, K; Kuboki, T; Clark, G T; Shinoda, M; Yamashita, A

    1998-11-01

    Cold pressor stimulation reportedly increases sympathetic nerve activity in human skeletal muscles. This study examined the effect of cold pressor stimulation on the resting haemodynamics of the right masseter muscle in normal individuals, using near-infrared spectroscopy. Nine healthy non-smoking males with no history of chronic muscle pain or vascular headaches participated. Their right hand was immersed in a water bath (4, 10, 15 degrees C) for exactly 1 min. Each trial lasted 7 min (1 min before, 1 min during, 5 min after stimulation) and a strictly random order was utilized for the three test temperatures and the mock trial. Masseter muscle haemoglobin concentration and oxygen saturation, as well as heart rate and blood pressure, were continuously recorded in each trial. After completing the four trials, each participant produced and sustained a 30-s maximum voluntary clench in the intercuspal position. Data across the four trials were baseline-corrected and then magnitude-normalized to the individual's highest absolute haemoglobin and oxygen signal during the 30-s maximal clenching effort. Haemoglobin and oxygen saturation increased progressively during cold pressor stimulation as the water temperature decreased (Hb, p < 0.0001; O2, p = 0.0327); very little effect was seen during the mock trial. Heart rate and blood pressure also increased progressively during the stimulation as the temperature decreased (heart rate, p = 0.0013; systolic blood pressure, p = 0.0042; diastolic blood pressure, p = 0.0156). These data suggest that cold pressor, stimulation induces a strong increase in intramuscular blood volume which appears to be due to both a local vasodilative response and increased cardiac output.

  2. Influence of gum-chewing on the haemodynamics in female masseter muscle.

    PubMed

    Abe, N; Yashiro, K; Hidaka, O; Takada, K

    2009-04-01

    Blood flow in active skeletal muscles provides energy substrate, oxygen and reduction of excessive heat and metabolic by-products. Although cyclic jaw motions such as those during mastication and speech articulation are the primitive oro-facial functions, possible effects of the cyclic muscle contractions on the intramuscular haemodynamics of the jaw muscles remains scarcely known. We investigated the masseteric haemodynamics during and after gum-chewing. Ten healthy female adults participated in the study. Electromyography, kinetics of masseter muscle oxygenation, electrocardiogram and blood pressure were recorded simultaneously. The subjects were asked to perform gum-chewing and cyclic jaw motion without gum bolus (empty-chewing task). The haemodynamics parameters were compared between the two experimental conditions. During gum-chewing task, deoxygenated haemoglobin and sympathetic nerve activity increased, while tissue blood oxygen saturation decreased. Blood pressure and parasympathetic nerve activity did not change. The overall behaviour of haemodynamic parameters during empty-chewing task was similar to that observed during gum-chewing task. However, the latency periods from the end of chewing until significant changes in the haemodynamic parameters were notably shorter (P < 0.05) in gum-chewing task as compared with those associated with empty-chewing task. The duration of the changes was shorter with empty-chewing than with gum-chewing. Fluctuations in masseter muscle haemodynamics associated with chewing jaw movement differed depending on the level of muscle contraction during movement. The differences became statistically significant immediately after the commencement of chewing and after the cessation movement. During the chewing movement, automatic nerve activities increased in response to the level of muscle contraction during movement.

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

    PubMed

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

    2016-06-01

    To assess the impact of aging on masticatory muscle function according to changes in hardness of solid food. 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 (5×10(3), 2×10(4), 5×10(4), and 5×10(5) N/m(2)) 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. 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). 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.

  4. Distribution of muscle fiber conduction velocity of m. masseter during voluntary isometric contraction.

    PubMed

    Mito, K; Sakamoto, K

    2000-01-01

    Muscle fiber conduction velocity (MFCV) is the velocity of an interference wave due to muscle fiber action potentials. In general, it has been reported that the value of MFCV in m. masseter is larger than that in limb and trunk muscles. But the values of MFCV in the reports were measured in part of the muscle, and the distribution of MFCV in the whole muscle including the end-plate and the tendon has not been measured. In this study, surface myoelectric signals are recorded in m. masseter during voluntary isometric contractions of 20, 30, and 40% MVC (maximum voluntary contraction) in eleven healthy male subjects with the use of array electrodes. The value of MFCV is found directly using an averaging method. The end-plate zone is concentrated in the lower quarter of the muscle. The distribution of MFCV depends on the location of the measured electrode. The largest value of MFCV of more than 20.0 m/s is obtained in the locations of the end-plate and the tendon. The minimum value of MFCV is obtained at the location of 10 mm measured from the end-plate along the direction of the muscle fiber to the tendon of the upper side. The mean values with the standard deviations during 20, 30, and 40% MVC are 10.3 +/- 0.7, 11.6 +/- 0.7, and 12.2 +/- 0.8 m/s, respectively. The MFCVs between the different neighboring locations are compared and found to be significant by a level of 1% for each contraction level. The MFCVs increase depending on the contraction levels for various electrode locations on the muscle.

  5. Influence of laterotrusive occlusal scheme on bilateral masseter EMG activity during clenching and grinding.

    PubMed

    Campillo, María José; Miralles, Rodolfo; Santander, Hugo; Valenzuela, Saúl; Fresno, María Javiera; Fuentes, Aler; Zúñiga, Claudia

    2008-10-01

    This study was designed to determine the effect of the occlusal scheme on masseter EMG activity at different jaw posture tasks. The sample included 30 healthy subjects with natural dentition and bilateral molar support, 15 with bilateral canine guidance, and 15 with bilateral group function. An inclusion criterion was that subjects had to be free of signs and symptoms of any dysfunction of the masticatory system. Bipolar surface electrodes were located on the left and right masseter muscles. EMG activity was recorded during the following jaw posture tasks: A. maximal clenching in the intercuspal position; B. grinding from intercuspal position to edge-to-edge lateral contact position; C. maximal clenching in the edge-to-edge lateral contact position; D. grinding from edge-to-edge lateral contact position to intercuspal position. EMG activity in tasks B, C, and D was lower than in task A (mixed model with unstructured covariance matrix). EMG activity was not significantly different with canine guidance or group function. EMG activity recorded on the nonworking side was higher than the working side during task C, and no different between tasks B or D. On the nonworking side, EMG activity in task B was significantly lower than C and D, and similar between task C and D. On the working side, EMG activity was significantly higher in task D than C and B, and in task B significantly higher than task C. The EMG patterns observed could be of clinical importance in the presence of parafunctional habits, i.e., clenching and/or grinding.

  6. Electromyographical analysis of the masseter muscle in dentulous and partially toothless patients with temporomandibular joint disorders.

    PubMed

    da Silva, M A M Rodrigues; Issa, J P M; Vitti, M; da Silva, A M Rodrigues; Semprini, M; Regalo, S C H

    2006-09-01

    This study had as objective to analyze with computerized electromyography the masseter muscles bilaterally in twenty individuals with temporomandibular joint dysfunction (DTM), being: the group I consisting of ten individuals with complete dentition and group II constituted by ten individuals with posterior dental absences; comparing nine clinical activities: rest before and after exercises, maximum habitual intercuspation (MIH), right and left laterality, forced centric occlusion, protrusion, bilateral molar bite and chewing. It was utilized the Electromyography K6I-Myotronics, with eight canals and surface silver electrodes. By means of the results analysis, we verified significant differences between the groups (p < 0.01), being group I, presented greater electromyographic activity (32.98 microvolts), than the group II (22.31 microvolts), suggesting that this individuals presented low muscular activity. The interaction between the groups and the clinical activities was significant (p < 0.01), as well as between the groups, clinical activities and muscles (p < 0.05). To clarify which amongst the relative averages the clinical activities were different, calculated the critical value of Tukey, being that rest before and after exercises, MIH, right and left laterality, presented averages with similar distributions, with values below of the values of Tukey, as well as forced centric occlusion, protrusion, bilateral molar bite and chewing presented higher values than Tukey. Based on this research's data, we concluded that the electromyographical analysis of the masseter muscles in Individuals with TMD, dentulous and with dental absence showed that individuals with TMD, dentulous or not, presented elevated muscular activity in rest position and individuals with TMD, dentulous, presented higher electromyographical activity than the individuals with TMD and lacking posterior teeth.

  7. 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

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

    PubMed

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

    2016-01-01

    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. 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. 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. 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 are not available.

  9. 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

  10. Electromyographic biofeedback training for reducing muscle pain and tension on masseter and temporal muscles: A pilot study.

    PubMed

    Criado, Laura; de La Fuente, Antonio; Heredia, Margarita; Montero, Javier; Albaladejo, Alberto; Criado, José-María

    2016-12-01

    Due to the absence of agreement about an effective unified treatment for temporomandibular disorders, non-invasive therapies such as EMG-biofeedback generate a greater interest. Furthermore, most studies to the present show methodological deficiencies that must be solved in the future, which makes important to emphasize this line of studies. Fourteen patients were selected for this case series study, and replied to a questionnaire concerning awareness of bruxism, painful muscles, and muscle tension. They also practiced an intraoral exploration (occlusal analysis and mandibular dynamics), and an extraoral exploration of the head and neck muscles and the temporomandibular joint. Before each session, patients responded to a questionnaire about the subjective perceived improvement. In each session, a period of three minutes of pre-biofeedback EMG activity of right masseter and temporal muscles was registered, then patients performed 30 iterations of visual EMG-biofeedback training and finally, a period of three minutes of post-EMG activity was also registered for those muscles. Patients performed four sessions. A decrease in painful symptoms was found for all patients since the first session. EMG activity decreases (p<0,05) in both muscles during the biofeedback training stage, in the four sessions. It is also observed a decrease (p<0,05) in EMG activity in the masseter muscle at the post-biofeedback stage, in the second and third sessions. There is likewise a decrease in EMG post-biofeedback activity of the temporal muscle (p<0,05) in sessions two, three, and four. EMG-biofeedback training produces a decrease in EMG activity in both masseter and temporal muscles during the session. This decrease persists during the post-biofeedback period since the second session. Also there is a decrease in painful symptoms for all patients. Key words:Muscle tension, muscle pain, EMG-biofeedback, masseter muscle, temporal muscle.

  11. 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

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

    PubMed

    Louca, Sofia; Christidis, Nikolaos; Ghafouri, Bijar; Gerdle, Björn; Svensson, Peter; List, Thomas; Ernberg, Malin

    2014-12-17

    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. 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. 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). 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.

  13. Management and control of isotonic contraction generated stress: evaluation of masseter muscle deformation pattern by means of ecography

    PubMed Central

    BUSATO, A.; BALCONI, G.; VISMARA, V.; BERTELÈ, L.; GARO, G.; DE GREGORIO, D.

    2016-01-01

    SUMMARY Purpose The objective of the following study is to observe the behavior of the six layers of the masseter during an isometric contraction at maximum exertion with the deformation pattern analysis method. Materials and methods This study has been conducted by use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5–12 MHz 40 mm) which allowed us to record a video (DCM) comprised of 45 frames per second. The probe was fixed to a brace and the patient was asked to clench their teeth as hard as possible, obtain the muscle’s maximum exertion, for 5 seconds three times, with 30 seconds intervals in between. Both right and left masseter muscles were analyzed. Then we applied to the resulting video a software (Mudy 1.7.7.2 AMID Sulmona Italy) for the analysis of muscle deformation patterns (contraction, dilatation, cross-plane, vertical strain, horizontal strain, vertical shear, horizontal shear, horizontal displacement, vertical displacement). The number of videos of masseter muscles in contraction at maximum exertion due to dental clenching made during this research is around 12,000. Out of these we chose 1,200 videos which examine 200 patients (100 females, 100 males). Results The analysis of the deformation patterns of the masseter allows us to observe how the six layers of the muscle have different and specific functions each, which vary depending on the applied force (application point, magnitude and direction) so that we find it impossible to assign to one of the three sections of the muscle a mechanical predominance. Therefore it appears that the three parts of the muscle have specific and synergistic tasks PMID:28280532

  14. Electromyographic biofeedback training for reducing muscle pain and tension on masseter and temporal muscles: A pilot study

    PubMed Central

    de La Fuente, Antonio; Heredia, Margarita; Montero, Javier; Albaladejo, Alberto; Criado, José-María

    2016-01-01

    Background Due to the absence of agreement about an effective unified treatment for temporomandibular disorders, non-invasive therapies such as EMG-biofeedback generate a greater interest. Furthermore, most studies to the present show methodological deficiencies that must be solved in the future, which makes important to emphasize this line of studies. Material and Methods Fourteen patients were selected for this case series study, and replied to a questionnaire concerning awareness of bruxism, painful muscles, and muscle tension. They also practiced an intraoral exploration (occlusal analysis and mandibular dynamics), and an extraoral exploration of the head and neck muscles and the temporomandibular joint. Before each session, patients responded to a questionnaire about the subjective perceived improvement. In each session, a period of three minutes of pre-biofeedback EMG activity of right masseter and temporal muscles was registered, then patients performed 30 iterations of visual EMG-biofeedback training and finally, a period of three minutes of post-EMG activity was also registered for those muscles. Patients performed four sessions. Results A decrease in painful symptoms was found for all patients since the first session. EMG activity decreases (p<0,05) in both muscles during the biofeedback training stage, in the four sessions. It is also observed a decrease (p<0,05) in EMG activity in the masseter muscle at the post-biofeedback stage, in the second and third sessions. There is likewise a decrease in EMG post-biofeedback activity of the temporal muscle (p<0,05) in sessions two, three, and four. Conclusions EMG-biofeedback training produces a decrease in EMG activity in both masseter and temporal muscles during the session. This decrease persists during the post-biofeedback period since the second session. Also there is a decrease in painful symptoms for all patients. Key words:Muscle tension, muscle pain, EMG-biofeedback, masseter muscle, temporal muscle

  15. [A preliminary study on the effects of the exogenous creatine phosphate on rat masseter muscle after unilateral chew].

    PubMed

    Xu, Long-bo; Wang, Zi-xian; Qi, Dong; Lin, Xue-fen; Ying, Wang-gui; Sun, Sheng-jun; Chen, Bin; Ji, Ping

    2010-08-01

    To study the effect of energy therapy on Ca2+ concentration and Ca2+ -ATP enzyme activity in rat master muscle after unilateral chew, and to discuss the protective action of the exogenous creatine phosphate on rat masseter muscle after unilateral chew. The 20 rats were randomly divided into 4 groups, A: Creatine phosphate normal control group; B: Creatine phosphate experimental group; C: Saline normal control group; D: Saline experimental group. The Ca2+ concentration were determined by atomic absorption spectrophotometry, the activity of the Ca2+ -ATP enzyme were determined by super-micro volume Ca2+ -ATP enzyme kit. (1) The Ca2+ concentration of the extraction side of group D which received the saline injection had significant difference compared with the non-extraction side (P = 0.007), the group C (P = 0.009) and the extraction side of group B (P = 0.01); (2) Ca2+ -ATP enzyme activity of group D were higher than its non-extraction side (P = 0.001), group C (P = 0.003) and the extraction side of group B (P = 0.001); (3) The ultrastructural changes of the rat masseter muscle under transmission electron microscope were as follows: The extraction side of group D have more severe pathological manifestations than non-extraction side. Both the extraction side and the non-extraction side of group B had a similar manifestation to the normal control group. Exogenous energy material, creatine phosphate, may have certain degree of protective effect on rat masseter muscles after unilateral chew. And it may become a possible way to improve the injury of the masseter muscle.

  16. Adaptation of rat jaw muscle fibers in postnatal development with a different food consistency: an immunohistochemical and electromyographic study

    PubMed Central

    Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Kinouchi, Nao; Kawakami, Emi; Tanne, Kazuo; Langenbach, Geerling E J; Tanaka, Eiji

    2010-01-01

    The development of the craniofacial system occurs, among other reasons, as a response to functional needs. In particular, the deficiency of the proper masticatory stimulus affects the growth. The purpose of this study was to relate alterations of muscle activity during postnatal development to adaptational changes in the muscle fibers. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a solid (hard-diet group) or a powder (soft-diet group) diet for 63 days. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time), the total burst number and their average length exceeding specified levels of the peak activity (5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of fibers by means of immunohistochemical staining and their cross-sectional area was measured. All muscle fibers were identified as slow type I and fast type IIA, IIX or IIB (respectively, with increasing twitch contraction speed and fatigability). At lower activity levels (exceeding 5% of the peak activity), the duty time of the anterior belly of the digastric muscle was significantly higher in the soft-diet group than in the hard-diet group (P < 0.05). At higher activity levels (exceeding 20 and 50% of the peak activity), the duty time of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.05). There was no difference in the duty time of the anterior temporalis muscle at any muscle activity level. The percentage of type IIA fibers of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P< 0.01) and the opposite was true with regard to type IIB fibers (P< 0

  17. Adaptation of rat jaw muscle fibers in postnatal development with a different food consistency: an immunohistochemical and electromyographic study.

    PubMed

    Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Kinouchi, Nao; Kawakami, Emi; Tanne, Kazuo; Langenbach, Geerling E J; Tanaka, Eiji

    2010-06-01

    The development of the craniofacial system occurs, among other reasons, as a response to functional needs. In particular, the deficiency of the proper masticatory stimulus affects the growth. The purpose of this study was to relate alterations of muscle activity during postnatal development to adaptational changes in the muscle fibers. Fourteen 21-day-old Wistar strain male rats were randomly divided into two groups and fed on either a solid (hard-diet group) or a powder (soft-diet group) diet for 63 days. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time), the total burst number and their average length exceeding specified levels of the peak activity (5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of fibers by means of immunohistochemical staining and their cross-sectional area was measured. All muscle fibers were identified as slow type I and fast type IIA, IIX or IIB (respectively, with increasing twitch contraction speed and fatigability). At lower activity levels (exceeding 5% of the peak activity), the duty time of the anterior belly of the digastric muscle was significantly higher in the soft-diet group than in the hard-diet group (P < 0.05). At higher activity levels (exceeding 20 and 50% of the peak activity), the duty time of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.05). There was no difference in the duty time of the anterior temporalis muscle at any muscle activity level. The percentage of type IIA fibers of the superficial masseter muscle in the soft-diet group was significantly lower than that in the hard-diet group (P < 0.01) and the opposite was true with regard to type IIB fibers (P < 0

  18. Effect of time of contraction and rest on the masseter and anterior temporal muscles activity in subjects with temporomandibular disorder.

    PubMed

    Ries, Lilian Gerdi Kittel; Graciosa, Maylli Daiani; Soares, Licerry Palma; Sperandio, Fabiana Flores; Santos, Gilmar Moraes; Degan, Viviane Veroni; Gadotti, Inaê Caroline

    2016-04-01

    Purpose The main objective of this study was to investigate the effect of time of contraction and rest on the masseter and temporal muscles activity. Methods 49 female subjects between 18 and 30 years of age were divided into TMD (n: 26) and control groups (n: 23). Surface electromyograph was used to evaluate the anterior temporal and masseter muscles during contraction and rest protocols. The root means square, median frequency and slope coefficient of the linear regression line parameters were analyzed. Results A significant effect of time in the contraction and rest muscle protocols was found. TMD patients showed a significant decrease in median frequency in the right masseter muscle and the slope coefficient in the right temporal muscle during the contraction protocol to control subjects. Conclusion Despite the TMD patients presented with higher fatigue susceptibility compared to the control group, both groups must meet the maximum time of 5 s of maximum voluntary contraction and at least 30 s rest between successive contractions of masticatory muscles during clinical or research assessment protocols.

  19. 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. Published by Elsevier Ireland Ltd.

  20. 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

  1. Association of Masseter Muscle Activities during Awake and Sleep Periods with Self-Reported Anxiety, Depression, and Somatic Symptoms

    PubMed Central

    Khawaja, Shehryar N; Iwasaki, Laura R; Dunford, Robert; Nickel, Jeffrey C; McCall, Willard; Crow, Heidi C; Gonzalez, Yoly

    2015-01-01

    Aim and background The objective of this study was to determine if duty factors (DF) of low-magnitude MMA during awake and sleep periods were associated with self-reports of anxiety, depression, and somatic symptoms, and if so, whether or not any associations were modified by gender or the presence of pain. Limited information is currently available in the literature regarding the association of low-magnitude masseter muscle activities (MMA) in habitual environmental settings and the presence of psychological symptoms. Materials and methods Sixty-eight consenting participants were classified using the Diagnostic Criteria for Temporomandibular Disorders examination and validated self-reporting psychological symptom evaluation questionnaires. Each subject also had masseter electromyography recordings during standardized biting tasks in 2 laboratory sessions to calibrate the in-field MMA collected during 3 awake and 3 sleep periods. Results During awake periods, subjects with self-reported depression and somatic symptoms had statistically high odds of having higher DF of low-magnitude MMA (defined by ≥ 75th percentile of sample). The association between high DF of low-magnitude MMA and self-reported depression symptoms was significantly augmented among male participants, whereas, the association between high DF of low-magnitude MMA and self-reported somatic symptoms was significantly increased among female participants without pain. Conclusion These pilot data support associations of low-magnitude masseter muscle activities with self-reported depression and somatic symptoms during awake periods. PMID:26709387

  2. Inhibitory effect of sympathetic stimulation on activities of masseter muscle spindles and the jaw jerk reflex in rats.

    PubMed Central

    Matsuo, R; Ikehara, A; Nokubi, T; Morimoto, T

    1995-01-01

    1. To evaluate sympathetic effects on jaw muscles, the discharges of masseter muscle spindle afferents, jaw muscle electromyographic (EMG) activities and blood flow changes were compared in anaesthetized decerebrate rats before and during electrical stimulation of the cervical sympathetic trunk. 2. To eliminate the possibility of efferent control from the trigeminal motoneurones, muscle spindle activity was recorded from the cut peripheral end of the masseter nerve. The absence of a sympathetic component in the masseter nerve was confirmed by the horseradish peroxidase method. 3. Electrical stimulation of the sympathetic nerve at frequencies within the physiological range reduced muscle spindle afferent discharges evoked by passive jaw opening. 4. Sympathetic stimulation also reduced the EMG activity evoked by the jaw jerk reflex, which may reflect a sympathetic effect on spindle afferents. After cessation of stimulation, a transient increase in EMG activity was observed, which may be due to efferent supply from the trigeminal motoneurones. During rhythmical jaw movements, no sympathetic effect on EMG activity was detected. 5. The above sympathetic effect on muscle spindle afferents and EMG activity was independent of blood flow changes. PMID:7776235

  3. Study on the association of ultrasonographic thickness and electromyographic activity of masseter muscle in young females with different vertical craniofacial morphology.

    PubMed

    Li, Hai-Tao; Cui, Chuan-Jiang; Lu, Shu-Lai; He, Kai-Yun

    2008-10-01

    To study the relationship between ultrasonographic thickness and EMG activity of the masseter muscle in subjects with different vertical craniofacial morphology. Thirty female students were separated into two groups (14 cases with high-angle, 16 cases with low-angle) based on SN-MP angle, FH-MP angle, and FHI. The thickness of the masseter muscle under relaxed conditions and during maximal clenching was assessed by ultrasonography. EMG activity of the masseter muscle under relaxed conditions and during maximal clenching was recorded with bipolar surface electrodes.All measurements were analyzed with SPSS 11.0 software package. Differences between groups were tested for statistical significance using Student's t test. The relationship between masseter muscle thickness and its EMG activity was estimated by Pearson's correlation coefficient. The thickness of the masseter muscle in the low-angle individuals was significantly greater than that in the high-angle individuals under relaxed conditions (P=0.009) and during maximal clenching (P=0.000). Although there was no significant difference in resting EMG activity between the two groups, the EMG activity of masseter muscle in the low-angle individuals was also significantly higher than that in the high-angle individuals during maximal clenching(P=0.022). Relaxed thickness of masseter muscle was significantly correlated with its mean maximum EMG activity in the low-angle group (r=0.61, P=0.003) and moderately correlated with that in the high-angle group (r=0.38, P=0.023). Similar correlation was found between contracted thickness of masseter muscle and the mean maximum EMG activity, being significantly correlated in the low-angle group (r=0.73, P=0.002) and moderately correlated in the high-angle group(r=0.53, P=0.006). The present findings support the concept that subjects with different vertical craniofacial morphology have different form and function of masseter muscle. The ultrasonographic thickness and EMG activity

  4. Electromyographic analysis of the masseter and temporal muscles in oralized deaf individuals.

    PubMed

    Regalo, S C H; Vitti, M; Semprini, M; Rosa, L B; Martinez, F H R M; Santos, C M; Hallak, J E C

    2006-01-01

    Deaf individuals show a number of difficulties related to the functionality of the stomatognathic system, mainly by reason of the little or no use of facial musculature during speech either due to the use of sign language or to the difficulty that these individuals have in articulating words. The stomatognathic system muscles play important roles in functions such as mastication, deglutition, and phonation. This study aimed to assess, by means of computerized bilateral electromyography (EMG), masseter and temporal muscles of 12 oralized deaf individuals in clinical activities that involve part of this masticatory musculature and compare this system's functionality with that of 12 normal listening individuals, performing the same activities. An 8-channel K6-I EMG Light Channel Surface Electromyography device was used (Myo-Tronics Co.Seattle, WA, USA), in addition to disposable double electrodes covered with silver chloride (Duotrodes; Myo-tronics Co., Seattle, WA) containing a conductor gel (Myogel- Myo-tronics Co., Seatlle, WA). The averaged rectified EMG values were normalized with reference to the EMG amplitude induced by a maximum bite force. The statistical analysis confirmed that there were any significant differences between the groups, clinical activities, and muscles, and also effects of interaction among them. The analysis made use of Variance Analysis (ANOVA). Significant differences (p < 0.01) for both muscles were found among the clinical conditions, with deaf individuals showing greater electromyographic activity for both muscles for the clinical activity protrusion. Deaf individuals showed a lower muscular activity for clinical activities that demanded a greater masseter and temporal muscular activity such as mastication, mouth opening and closing, and dental compression. Greater electromyographic values were found for both deaf individuals and healthy controls during clinical activities of mastication and dental compression. Based on the obtained

  5. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. 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

  7. Myosin heavy chain mRNA isoforms in masseter muscle before and after orthognathic surgery.

    PubMed

    Harzer, Winfried; Worm, Margret; Gedrange, Tomasz; Schneider, Matthias; Wolf, Peter

    2007-10-01

    Orthognathic surgery leads to changed jaw position and force vector of mastication to which the muscles must adapt. The aim of the present study was to determine the relative expression of myosin heavy chain (MyHC) messenger RNA (mRNA) isoforms in different types of human masseter muscle fiber under consideration of change in the number of occlusal contacts before and 6 months after surgery. Muscle biopsies were taken from the anterior and posterior parts of both sides in 30 patients with prognathic and retrognathic mandibles. Specific mRNA MyHC analysis was made by real-time polymerase chain reaction to quantify the isoforms I, IIa, and IId/x. There was a shift in the relative content from type I (46% before, 37% after) to type IIa (29% before, 42% after). This shift correlates with number of teeth in occlusion. Correlation between isoform shift and number of teeth in occlusion indicates higher mastication force which stabilizes the treatment result.

  8. 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

    2015-03-02

    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.

  9. Reflex responses of human masseter motor units to mechanical stimulation of the teeth.

    PubMed

    Uginčius, P; Atiş, E S; Türker, K S

    2014-01-01

    Our aim was to investigate the jaw reflexes using both the probability- and the discharge rate-based analysis methods. Twelve consenting volunteer subjects participated in this study. Subjects bit gently on bite bars that carried the impression of their teeth. Surface and intramuscular electrical activity of the masseter was recorded. With the help of audio feedback from one motor unit, each subject bit to discharge the unit at a fixed rate. While the subject continuously activated the selected motor unit, 4-N stimuli were delivered to the upper right central incisor either at a rapid or a slow rate. For each trial, ≥300 stimuli were delivered, and, once a trial was completed, local anesthetic block was applied around the stimulated tooth, and the experiment was repeated. While preceding local anesthesia, the rapid-rate stimuli ("tap") induced substantial inhibitory reflex responses; during local anesthetic block, the same stimulus induced excitatory and inhibitory reflex responses. Slow-rate stimuli ("push"), on the other hand, usually generated a combination of inhibitory and excitatory responses that disappeared completely during the local anesthetic block. This study discovered that the strength of the inhibitory reflex response to a tooth-tap stimulus was much larger than previously reported. This study also found that whereas the probability-based analyses were better for illustrating the existence and latency of small earlier responses, the discharge rate-based method was better for indicating the duration of earlier responses and the existence, sign, and duration of later responses.

  10. Schedule-induced masseter EMG in facial pain subjects vs. no-pain controls.

    PubMed

    Gramling, S E; Grayson, R L; Sullivan, T N; Schwartz, S

    1997-02-01

    Empirical reports suggest that oral habits (e.g., teeth clenching) may be behavioral mediators linking stress to muscle hyperreactivity and the development of facial pain. Another report suggests that excessive behavioral adjuncts develop in conjunction with fixed-time stimulus presentation. The present study assessed the extent to which the oral habits exhibited by facial pain patients are schedule-induced. Subjects with Temporomandibular Disorder (TMD) symptomatology (n = 15) and pain-free controls (n = 15) participated in a 4-phase experiment (adaptation, baseline, task, recovery) designed to elicit schedule-induced behaviors. Self-report of oral habits and negative affect were recorded after each phase. Objective measures of oral habits were obtained via behavioral observation and masseter EMG recordings. Results revealed that negative arousal significantly increased during the fixed-time (FT) task and was also associated with increased oral habits among the TMD subjects. Moreover, 40% of the TMD subjects and none of the controls exhibited a pattern of EMG elevations in the early part of the inter-stimulus interval that met a strict criteria for scheduled-induced behavior per se. Taken together, these results suggest that the TMD subjects were engaging in schedule-induced oral habits. The adjunctive behavior literature seems to provide a plausible explanation as to how oral habits develop and are maintained in TMD patients, despite their painful consequences.

  11. Estimation of tendon-plane orientation within human masseter muscle from reconstructed magnetic resonance images.

    PubMed

    Lam, E W; Hannam, A G; Christiansen, E L

    1991-01-01

    The human masseter is a powerful multipennate jaw elevator with complex internal architecture. The three-dimensional disposition of tendon planes within the muscle is thought to be an important determinant of function. We selected five adult subjects and used cephalometric radiography, magnetic resonance imaging and graphical, three-dimensional reconstruction to describe the organization of these planes within the muscle. Putative tendon planes were fitted to the surfaces of the three-dimensional reconstructions, and these were related to the mid-sagittal plane in the coronal and transverse views. To confirm whether putative planes disclosed by magnetic resonance represented true anatomical entities, a fresh human cadaver head was imaged and the magnetic resonance slices were compared with cryosections obtained in the same planes. Tendon-plane angulation appeared to be related to ramal length and lower face height measured cephalometrically. In the transverse view, the tendon planes appeared roughly to follow the angulations of the zygomatic arch and the lateral face of the mandibular ramus. These findings suggest that the angulation of tendon planes, and possibly pennation angles, are different depending on the viewing angle. Rather than reporting pennation angle as a single angle, alpha, which has been the convention, it may be more appropriate to express it as a three-dimensional angle relative to the normal of a particular tendon plane. The inference is that muscle fibres inserting on either side of a central tendon may need to develop different tensile forces if translation is to occur directly along the tendon axis.

  12. Functional relationships between the masseter and sternocleidomastoid muscle activities during gum chewing:.

    PubMed

    Shimazaki, Kazuo; Matsubara, Nozomu; Hisano, Masataka; Soma, Kunimichi

    2006-05-01

    The purpose of this study was to investigate the functional relationship between masseter muscle (MM) and sternocleidomastoid muscle (SCM) activities and between mandibular and head movements during mastication, under experimental muscle fatigue. The sample consisted of 12 adults with individually normal occlusion. The subjects were asked to chew gum at three different times: before maximum clenching, immediately after maximum clenching, and 3 minutes after maximum clenching. At these times, we examined the activity of the MM and SCM as well as the movement of the mandible and head. The activity and movement were simultaneously measured using both electromyography and the motion capture system. The MM activity time after clenching was significantly shorter than that before clenching, whereas the SCM activity time was significantly longer after clenching. There was no significant difference in the changes of three-dimensional distance of the mandibular movement between the respective times. On the other hand, the changes in the three-dimensional distance of head movement after clenching increased when compared with before clenching. Furthermore, the difference in the time of MM and SCM activity onset and of mandibular and head movement onset after clenching was shorter than that before clenching. A functional relationship exists between the MM and SCM activities and between mandibular and head movements during mastication.

  13. Sarcoglycan complex in masseter and sternocleidomastoid muscles of baboons: an immunohistochemical study.

    PubMed

    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

    2015-06-05

    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.

  14. SURFACE ELECTROMYOGRAPHY OF MASSETER AND TEMPORAL MUSCLES WITH USE PERCENTAGE WHILE CHEWING ON CANDIDATES FOR GASTROPLASTY.

    PubMed

    Santos, Andréa Cavalcante Dos; Silva, Carlos Antonio Bruno da

    Surface electromyography identifies changes in the electrical potential of the muscles during each contraction. The percentage of use is a way to treat values enabling comparison between groups. To analyze the electrical activity and the percentage of use of masseter and temporal muscles during chewing in candidates for gastric bypass. It was used Surface Electromyography Miotool 200,400 (Miotec (r), Porto Alegre/RS, Brazil) integrated with Miograph 2.0 software, involving patients between 20-40 years old. Were included data on electrical activity simultaneously and in pairs of temporal muscle groups and masseter at rest, maximum intercuspation and during the chewing of food previously classified. Were enrolled 39 patients (59 women), mean age 27.1+/-5.7. The percentage of use focused on temporal muscle, in a range of 11-20, female literacy (n=11; 47.82) on the left side and 15 (65.21) on the right-hand side. In the male, nine (56.25) at left and 12 (75.00) on the right-hand side. In masseter, also in the range of 11 to 20, female literacy (n=10; 43.48) on the left side and 11 (47.83) on the right-hand side. In the male, nine (56.25) at left and eight (50.00) on the right-hand side. 40-50% of the sample showed electrical activity in muscles (masseter and temporal) with variable values, and after processing into percentage value, facilitating the comparison of load of used electrical activity between the group, as well as usage percentage was obtained of muscle fibers 11-20% values involving, representing a range that is considered as a reference to the group studied. The gender was not a variable. A eletromiografia de superfície identifica variações dos potenciais elétricos dos músculos durante cada contração realizada. O percentual de uso é uma forma de tratar valores possibilitando comparação entre grupos. Analisar a atividade elétrica e o percentual de uso dos músculos masséteres e temporais durante a mastigação em candidatos à gastroplastia

  15. Immunohistochemical localization of alpha(1a)-adrenoreceptors in muscle spindles of rabbit masseter muscle.

    PubMed

    Bombardi, C; Grandis, A; Chiocchetti, R; Bortolami, R; Johansson, H; Lucchi, M L

    2006-04-01

    The expression of alpha(1a)-adrenoreceptors (alpha(1a)-ARs) within the muscle spindles of rabbit masseter muscle was investigated. The alpha(1a)-ARs were detected by immunohistochemical fluorescent method and examined along the entire length of 109 cross serially sectioned spindles. The sympathetic fibers were visualized by the immunofluorescent labeling of the noradrenaline synthesizing enzymes tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH). In order to recognize the intrafusal muscle fiber types, antibodies for different myosin heavy chain isoforms (MyHCI) were used. TH and DBH immunolabeled nerve fibers have been observed within the capsule lamellar layers, in the periaxial fluid space and close to intrafusal muscle fibers. The alpha(1a)-ARs were detected on the smooth muscle cells of the blood vessels coursing in the muscle and in the capsule lamellar layers or within the periaxial fluid space of the spindles. Moreover, at the polar regions of a high percentage (88.1%) of muscle spindles a strong alpha(1a)-ARs immunoreactivity was present on the intrafusal muscle fibers. In double immunostained sections for alpha(1a)-ARs and MyHCI it was evidenced that both bag, and nuclear chain fibers express alpha(1a)-ARs. The receptors that we have detected by immunofluorescence may support a direct control by adrenergic fibers on muscle spindle.

  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. Frequency analyses of EMG power spectra of anterior temporal and masseter muscles in children and adults.

    PubMed

    Takarada, T; Larrinaga, G A; Nishida, F; Nishino, M

    1990-01-01

    To study the functional change of masticatory muscles during growth and development, frequency analyses of surface electromyogram (EMG) power spectra were carried out. The subjects were six children (five males and one female), aged 4.5 +/- 0.2 years, having full deciduous dentition (Hellman's dental age IIA) and six adults (four males and two females), aged 27.7 +/- 3.8 years, having full permanent dentition. EMG signals were recorded bilaterally by using bipolar silver-surface electrodes from the anterior temporal and masseter muscles while the subjects were chewing gum and while performing maximum clenching in the intercuspal position. A fast Fourier transform algorithm was used to obtain the power-spectral density function and the power spectra of the EMG signals. Since the total power value from 62.5 to 1000 Hz was 100 percent, the frequencies at 25, 50, 75, and 90 percent of the cumulative power were calculated. The results showed that the frequencies at every percent of the cumulative power were age-dependent and that the EMG power spectra patterns in adult muscles were shifted to significantly lower frequencies than those in child muscles. The shift was probably caused by differences in the proportion of fiber type and fiber size between muscles of children and adults.

  18. Functional characteristics of the rat jaw muscles: daily muscle activity and fiber type composition

    PubMed Central

    Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Tanaka, Eiji; van Wessel, Tim; Langenbach, Geerling E J; Tanne, Kazuo

    2009-01-01

    Skeletal muscles have a heterogeneous fiber type composition, which reflects their functional demand. The daily muscle use and the percentage of slow-type fibers have been shown to be positively correlated in skeletal muscles of larger animals but for smaller animals there is no information. The examination of this relationship in adult rats was the purpose of this study. We hypothesized a positive relationship between the percentage of fatigue-resistant fibers in each muscle and its total duration of use per day. Fourteen Wistar strain male rats (410–450 g) were used. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, deep masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time) exceeding specified levels of the peak activity (2, 5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of the fibers by means of immunohistochemical staining. At lower activity levels (exceeding 2 and 5% of the peak activity), the duty time of the anterior belly of digastric muscle was significantly (P < 0.01) longer than those of the other muscles. The anterior belly of digastric muscle also contained the highest percentage of slow-type fibers (type I fiber and hybrid fiber co-expressing myosin heavy chain I + IIA) (ca. 11%; P < 0.05). By regression analysis for all four muscles, an inter-muscular comparison showed a positive relationship between the duty time (exceeding 50% of the peak activity) and the percentage of type IIX fibers (P < 0.05), which demonstrate intermediate physiological properties relative to type IIA and IIB fibers. For the jaw muscles of adult male rats, the variations of fiber type composition and muscle use suggest that the muscle containing the largest amounts of slow-type fibers (the anterior belly of digastric muscle) is mainly

  19. Functional characteristics of the rat jaw muscles: daily muscle activity and fiber type composition.

    PubMed

    Kawai, Nobuhiko; Sano, Ryota; Korfage, Joannes A M; Nakamura, Saika; Tanaka, Eiji; van Wessel, Tim; Langenbach, Geerling E J; Tanne, Kazuo

    2009-12-01

    Skeletal muscles have a heterogeneous fiber type composition, which reflects their functional demand. The daily muscle use and the percentage of slow-type fibers have been shown to be positively correlated in skeletal muscles of larger animals but for smaller animals there is no information. The examination of this relationship in adult rats was the purpose of this study. We hypothesized a positive relationship between the percentage of fatigue-resistant fibers in each muscle and its total duration of use per day. Fourteen Wistar strain male rats (410-450 g) were used. A radio-telemetric device was implanted to record muscle activity continuously from the superficial masseter, deep masseter, anterior belly of digastric and anterior temporalis muscles. The degree of daily muscle use was quantified by the total duration of muscle activity per day (duty time) exceeding specified levels of the peak activity (2, 5, 20 and 50%). The fiber type composition of the muscles was examined by the myosin heavy chain content of the fibers by means of immunohistochemical staining. At lower activity levels (exceeding 2 and 5% of the peak activity), the duty time of the anterior belly of digastric muscle was significantly (P < 0.01) longer than those of the other muscles. The anterior belly of digastric muscle also contained the highest percentage of slow-type fibers (type I fiber and hybrid fiber co-expressing myosin heavy chain I + IIA) (ca. 11%; P < 0.05). By regression analysis for all four muscles, an inter-muscular comparison showed a positive relationship between the duty time (exceeding 50% of the peak activity) and the percentage of type IIX fibers (P < 0.05), which demonstrate intermediate physiological properties relative to type IIA and IIB fibers. For the jaw muscles of adult male rats, the variations of fiber type composition and muscle use suggest that the muscle containing the largest amounts of slow-type fibers (the anterior belly of digastric muscle) is mainly

  20. Effects of chronic Akt/mTOR inhibition by rapamycin on mechanical overload-induced hypertrophy and myosin heavy chain transition in masseter muscle.

    PubMed

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

    2013-01-01

    To examine the effects of the Akt/mammalian target of rapamycin (mTOR) pathway on masseter muscle hypertrophy and myosin heavy chain (MHC) transition in response to mechanical overload, we analyzed the effects of bite-opening (BO) on the hypertrophy and MHC composition of masseter muscle of BO-rats treated or not treated with rapamycin (RAPA), a selective mTOR inhibitor. The masseter muscle weight in BO-rats was significantly greater than that in controls, and this increase was attenuated by RAPA treatment. Expression of slow-twitch MHC isoforms was significantly increased in BO-rats with/without RAPA treatment, compared with controls, but the magnitude of the increase was much smaller in RAPA-treated BO-rats. Phosphorylation of p44/42 MAPK (ERK1/2), which preserves fast-twitch MHC isoforms in skeletal muscle, was significantly decreased in BO-rats, but the decrease was abrogated by RAPA treatment. Calcineurin signaling is known to be important for masseter muscle hypertrophy and fast-to-slow MHC isoform transition, but expression of known calcineurin activity modulators was unaffected by RAPA treatment. Taken together, these results indicate that the Akt/mTOR pathway is involved in both development of masseter muscle hypertrophy and fast-to-slow MHC isoform transition in response to mechanical overload with inhibition of the ERK1/2 pathway and operates independently of the calcineurin pathway.

  1. The efficiency of botulinum toxin type A for the treatment of masseter muscle pain in patients with temporomandibular joint dysfunction and tension-type headache.

    PubMed

    Pihut, Malgorzata; Ferendiuk, Ewa; Szewczyk, Michal; Kasprzyk, Katarzyna; Wieckiewicz, Mieszko

    2016-01-01

    Temporomandibular joint dysfunction are often accompanied by symptoms of headache such as tension-type headache which is the most frequent spontaneous primary headache. Masseter muscle pain is commonly reported in this group. The purpose of the study was to assess the efficiency of intramuscular botulinum toxin type A injections for treating masseter muscle pain in patients with temporomandibular joint dysfunction and tension-type headache. This prospective outcome study consisted of 42 subjects of both genders aged 19-48 years diagnosed with masseter muscle pain related to temporomandibular joint dysfunction and tension-type headache. The subjects were treated by the intramuscular injection of 21 U (mice units) of botulinum toxin type A (Botox, Allergan) in the area of the greatest cross-section surface of both masseter bellies. Pain intensity was evaluated using visual analogue scale (VAS) and verbal numerical rating scale (VNRS) 1 week before the treatment and 24 weeks after the treatment. The obtained data were analyzed using the Wilcoxon matched pairs test (p ≤ 0,005). The results of this study showed a decrease in the number of referred pain episodes including a decrease in pain in the temporal region bilaterally, a reduction of analgesic drugs intake as well as a decrease in reported values of VAS and VNRS after injections (p = 0,000). The intramuscular botulinum toxin type A injections have been an efficient method of treatment for masseter muscle pain in patients with temporomandibular joint dysfunction and tension-type headache.

  2. 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. © 2011 Blackwell Publishing Ltd.

  3. Noninvasive estimation of the location of the end plate in the human masseter muscle using surface electromyograms with an electrode array.

    PubMed

    Iwasaki, S; Tokunaga, T; Baba, S; Tanaka, M; Kawazoe, T

    1990-10-01

    The purpose of this study was to estimate the location of the end plate in the masseter muscle, and to decide the appropriate position of surface electrodes for recording electromyograms (EMG) in humans. The subjects were 16 males who had no signs or symptoms of muscular disease. Identical electrode arrays were placed on the masseter muscles on each side. Each subject was asked to clench in the intercuspal position at various levels of maximum EMG amplitude. Eleven amplified EMGs were monitored simultaneously using a linear electrode array consisting of 12 stainless steel contacts. Various values were observed in different regions of the masseter muscle for the root mean square rectified EMG during brief isometric contraction. The superior region of the muscle had lower values than the inferior. The end-plate zone, which is in the center of the lower half of the masseter muscle, showed a lower amplitude than other regions. The propagation of motor unit action potentials was also observed. It was concluded that, aside from the end-plate zone, a position within the lower half of the muscle was most suitable for recording the surface EMG of the masseter muscle.

  4. Spontaneous Blinking Kinetics on Paralytic Lagophthalmos After Lid Load with Gold Weight or Autogenous Temporalis Fascia Sling.

    PubMed

    Wambier, Sarah P F; Garcia, Denny M; Cruz, Antonio A V; Messias, Andre

    2016-04-01

    To assess the upper eyelid kinematics during spontaneous blinking in unilateral paralytic lagophthalmos before and after upper eyelid load with gold weight (GW) or autogenous temporalis fascia (TF) sling. Comparative case series. Patients with long-standing unresolved unilateral facial palsy who underwent surgical treatment with GW (n = 8) or upper lid cerclage with TF (n = 10). The contralateral eyelid served as the control for each patient (control group). Preoperative and postoperative measurements of spontaneous blink kinematics with magnetic search coil and clinical assessment of lid margin position, lagophthalmos and ocular surface exposure, and determine amplitude, maximum velocity and main sequence of spontaneous blinks; relative amplitude of blinks to the pupil center; ocular surface exposure scores; magnitude of lagophthalmos and mid-pupil lid distances. The mean (±SE) down-phase amplitude ratio between paralyzed and contralateral eyelids (blink gain) was 10.0% preoperatively for both groups and significantly increased to 29 ± 6% for the GW group (p < 0.05) and 23 ± 4% for the TF group (p < 0.05). At 6 months the gain was significant for the GW group only (32 ± 7%, p < 0.05). There was no effect on the maximum velocity of the blinks or the main sequence of paretic and contralateral blinks with either surgery. Both procedures lowered the lid margin increasing the number of blinks that reached the pupil center. At 6 months this effect was prominent only for the GW group. Exposure keratopathy scores and lagophthalmos decreased postoperatively especially in the GW group. The beneficial effect of lid load surgeries result from a combination of a small increase on the spontaneous blink amplitude and a static effect due to the reduction of the distance between the lid margin and pupil center.

  5. [Effectiveness of digital three-dimensional titanium mesh in repairing skull defect under temporalis and reconstructing temporal muscle attachment points].

    PubMed

    Feng, Jiafeng; Yang, Cheng; Cui, Wei

    2014-05-01

    To investigate the technique and the effectiveness of digital three-dimensional (3-D) titanium mesh in repairing skull defect under the temporalis and reconstructing temporal muscle attachment points. Between January 2009 and December 2012, 58 patients with skull defect after decompressive craniectomy at the frontal temporal region were treated. Of 58 patients, 33 were male and 25 were female, aged 17-62 years (mean, 36.2 years). The disease duration was 15 weeks to 25 months (mean, 5.8 months). The size of skull defect ranged from 8 cm x 6 cm to 15 cm x 12 cm. The patients underwent skull impairment patch surgery with digital 3-D titanium mesh and reconstruction of the temporal muscle attachment points at titanium mesh temporal corresponding position. The operation time was 60-100 minutes (mean, 87 minutes). After operation, 2 cases had slight red swelling with little exudation at skin incision margin, which was cured after symptomatic treatment; 2 cases had symptom of headache, which disappeared after incision healing; primary healing of incision was obtained in the other patients. Fifty-eight patients were followed up 6-24 months (mean, 16 months). The patients were satisfied with shaping, and had no chewing pain. Head CT after operation showed good fixation of titanium mesh and titanium nail, and satisfactory skull shape symmetry; no postoperative complication of subcutaneous effusion, intracranial bleeding, titanium mesh loosening, or titanium mesh exposure occurred. The surgery technique of digital 3-D titanium mesh to repair skull defect in frontal temporal region and to reconstruct temporal muscle attachment points at the corresponding position of titanium mesh, basically can obtain anatomical reduction of the skull, frontal temporal, and each layer of scalp. It has the advantages of less complication, less titanium nail, and satisfactory shape.

  6. 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

  7. 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

  8. Classification of muscle spindle afferents innervating the masseter muscle in rats.

    PubMed

    Masri, Radi; Ro, Jin Y; Dessem, Dean; Capra, Norman

    2006-09-01

    Taylor et al. [Taylor, A., Durbaba, R., Rodgers, J.F., 1992a. The classification of afferents from muscle spindles of the jaw-closing muscles of the cat. J Physiol 456, 609-628] developed a method to classify muscle spindle afferents using succinylcholine (Sch) and ramp and hold stretches. They demonstrated that cat jaw muscle spindle afferents show high proportion of intermediate responses to ramp and hold jaw stretch. Together with observations on the responses to Sch their data suggests that the majority of jaw muscle spindle afferents are influenced by a combination of nuclear bag(2) and nuclear chain fibres. Relatively few are influenced solely by nuclear bag(1) fibres. The purpose of this study was to categorize jaw muscle spindle afferent in rodents in response to ramp and hold stretches. Several measures were used to classify spindle afferents including (1) conduction velocity, (2) coefficient of variation (C.V.) of the interspike interval during jaw opening, and (3) the dynamic sensitivity and the initial discharge of spindle afferents before and after succinylcholine infusion (Sch, 100mg/kg, i.v.). Consistent with observations in the cat jaw muscles, the distribution of the conduction velocity and the C.V. of Vmes masseter afferents were unimodal. Therefore, these parameters were of little value in functional classification of spindle innervation. Succinylcholine injection either markedly increased the dynamic sensitivity or produced no change in Vmes afferents. Unlike cat jaw muscle spindle afferents, the effect of Sch on the initial discharge was not clearly separable from those responding or not responding to Sch. These results suggest that rat jaw muscle spindle afferents, have physiological properties that are primarily intermediate in nature and are likely to reflect a predominance of influence from nuclear bag(2) and chain fibres. However, the distinction between bag(2) and chain fibres influences is not as clearly defined in the rat compared to

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

    PubMed

    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.

  10. The effect of a cholecystokinin agonist on masseter muscle activity in the cat.

    PubMed

    Sitthisomwong, P; Weiner, S; Levin, L; Reisman, S; Siegel, A

    2000-10-01

    The CCK(B) agonist, pentagastrin, has been shown to induce anxiety in human subjects. Similarly, in the cat model, pentagastrin facilitates the expression of hypothalamically activated emotional behavior. Because hypothalamically mediated emotional behavior is also accompanied by increased EMG activity in the jaw muscles, these experiments were designed to examine the combined effects of administration of pentagastrin with activation of hypothalamically mediated emotional behavior upon jaw muscle EMG activity. Electrodes were carefully lowered through previously placed guide tubes overlying the hypothalamus until a behavioral site was identified. Following the establishment of a stable threshold current for eliciting an emotional behavioral response, the skin overlying the ipsilateral masseter muscle was shaved and cleaned with alcohol, and surface electrodes were attached. The EMG was recorded, amplified, digitized, and stored in a microcomputer for analysis. Mean power frequencies (MPF) and latencies for behavior were calculated for baseline prior to infusion of all drugs. Following this, the effects of intravenous administration of pentagastrin and the CCK(B) antagonist LY288513 on the MPF were determined. The infusion of the CCK(B) agonist, pentagastrin (0.77, 1.92, and 3.84 microg/kg), decreased MPF in a time-related manner. The effects of pentagastrin 1.92 microg/kg were blocked by the CCK(B) antagonist, LY288513 (6.54 microg/kg). In addition, the infusion of LY288513 alone increased MPF. These results are surprising in that pentagastrin's anxiogenic properties would appear to make it likely to facilitate motor activity, not suppress it.

  11. Mechanoreceptors around the tooth evoke inhibitory and excitatory reflexes in the human masseter muscle.

    PubMed Central

    Brodin, P; Türker, K S; Miles, T S

    1993-01-01

    1. The reflex responses evoked in the human masseter muscle by controlled mechanical stimulation of an incisor tooth were examined electromyographically. The stimuli were (slow) pushes and (brisk) taps of about 0.5-3 N peak force, applied orthogonally to the labial surface. 2. The brisk taps elicited a short-latency inhibitory reflex that was often followed by an excitatory peak, as has been described earlier. The inhibition increased as the taps became stronger. 3. Slow pushes evoked a long-latency, primarily excitatory response. The excitation increased with stronger, faster rise-time pushes; however, with the stronger stimuli, the short-latency inhibitory response often became evident before the onset of the excitation. 4. The reflex responses to 3 N pushes and 2 N taps were abolished when the receptors around the tooth were blocked with local anaesthetic, indicating that the response was elicited from receptors located within the periodontal area. 5. Prolonged, rapid-onset displacements evoked a complex reflex response that combined the characteristics of the taps and the pushes. 6. The most likely explanation for the different responses evoked by the pushes and taps is that the patterns of afferent activity elicited by the slow and fast tooth displacements activated different interneuronal pathways to motoneurones. 7. The inhibitory response to taps is essentially a protective reflex which probably serves to reduce the activity of the jaw-closing muscles when one bites unexpectedly on hard objects. It is suggested that the excitatory response may contribute to the muscle activity required to hold food between the teeth during chewing, or may act as a load compensation reflex to control chewing force. PMID:8229826

  12. Ultrasound and analysis of the deformation patterns of the masseter muscle: comparing surgical anatomy, ultrasound and functional anatomy

    PubMed Central

    BUSATO, A.; BALCONI, G.; VISMARA, V.; BERTELÈ, L.; GARO, G.; DE GREGORIO, D.

    2016-01-01

    SUMMARY Purpose We have tried to demonstrate whether the analysis of the muscle strain allows us to identify the three distinct functional areas of the architecture of the masseter, as one would see them by performing or viewing an anatomical dissection of said muscle, and whether these sections have behave differently in terms of origin and coping of the strain they face (quantitative analysis). Materials and methods This work has been elaborated by the use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5–12 MHz 40 mm) which allowed us to record a 45 frame per second video (DCM). Videos has been elaborated by use of an ultrasound machine (MicrUs ext-1H Telemed Medical Systems Milano) and a linear probe (L12-5l40S-3 5–12 MHz 40 mm) which allowed us to record a 45 frame per second video (DCM). We applied to the resulting video a software (Mudy 1.7.7.2 AMID Sulmona Italy) for the analysis of muscle deformation patters (contraction, dilatation, cross-plane, vertical strain, horizontal strain, vertical shear, horizontal shear, horizontal displacement, vertical displacement). The number of videos of masseter muscles in contraction at maximum exertion due to dental clenching made during this research is around 12,000. Out of these we chose 1,200 videos which examine 200 patients (100 females, 100 males). Results The deformation pattern analysis of the skeletal muscle on ultrasound basis seems to be an adequate instrument to use during the investigation of the functional structure of the masseter muscle given its ability to highlight the distinct activity of each separate part of the muscle. Conclusions Moreover the strain does not apply to the muscle uniformly; instead it varies according to the observed area. PMID:28280530

  13. Potential clinical application of masseter and temporal muscle massage treatment using an oral rehabilitation robot in temporomandibular disorder patients with myofascial pain.

    PubMed

    Ariji, Yoshiko; Nakayama, Miwa; Nishiyama, Wataru; Ogi, Nobumi; Sakuma, Shigemitsu; Katsumata, Akitoshi; Kurita, Kenichi; Ariji, Eiichiro

    2015-10-01

    To investigate the safety, suitable treatment regimen, and efficacy of masseter and temporal muscle massage treatment using an oral rehabilitation robot. Forty-one temporomandibular disorder (TMD) patients with myofascial pain (8 men, 33 women, median age: 46 years) were enrolled. The safety, suitable massage regimen, and efficacy of this treatment were investigated. Changes in masseter muscle thickness were evaluated on sonograms. No adverse events occurred with any of the treatment sessions. Suitable massage was at pressure of 10 N for 16 minutes. Five sessions were performed every 2 weeks. Total duration of treatment was 9·5 weeks in median. Massage treatment was effective in 70·3% of patients. Masseter muscle thickness decreased with treatment in the therapy-effective group. This study confirmed the safety of massage treatment, and established a suitable regimen. Massage was effective in 70·3% of patients and appeared to have a potential as one of the effective treatments for myofascial pain.

  14. 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

  15. Spatiotemporal Profiles of Proprioception Processed by the Masseter Muscle Spindles in Rat Cerebral Cortex: An Optical Imaging Study

    PubMed Central

    Fujita, Satoshi; Kaneko, Mari; Nakamura, Hiroko; Kobayashi, Masayuki

    2017-01-01

    Muscle spindles in the jaw-closing muscles, which are innervated by trigeminal mesencephalic neurons (MesV neurons), control the strength of occlusion and the position of the mandible. The mechanisms underlying cortical processing of proprioceptive information are critical to understanding how sensory information from the masticatory muscles regulates orofacial motor function. However, these mechanisms are mostly unknown. The present study aimed to identify the regions that process proprioception of the jaw-closing muscles using in vivo optical imaging with a voltage-sensitive dye in rats under urethane anesthesia. First, jaw opening that was produced by mechanically pulling down the mandible evoked an optical response, which reflects neural excitation, in two cortical regions: the most rostroventral part of the primary somatosensory cortex (S1) and the border between the ventral part of the secondary somatosensory cortex (S2) and the insular oral region (IOR). The kinetics of the optical signal, including the latency, amplitude, rise time, decay time and half duration, in the S1 region for the response with the largest amplitude were comparable to those in the region with the largest response in S2/IOR. Second, we visualized the regions responding to electrical stimulation of the masseter nerve, which activates both motor efferent fibers and somatosensory afferent fibers, including those that transmit nociceptive and proprioceptive information. Masseter nerve stimulation initially excited the rostral part of the S2/IOR region, and an adjacent region responded to jaw opening. The caudal part of the region showing the maximum response overlapped with the region responding to jaw opening, whereas the rostral part overlapped with the region responding to electrical stimulation of the maxillary and mandibular molar pulps. These findings suggest that proprioception of the masseter is processed in S1 and S2/IOR. Other sensory information, such as nociception, is

  16. 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

  17. 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.

  18. 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. © 2015 Wiley Periodicals, Inc.

  19. Random control trial of dermis-fat graft and interposition of temporalis fascia in the management of temporomandibular ankylosis in children.

    PubMed

    Mehrotra, D; Pradhan, R; Mohammad, S; Jaiswara, C

    2008-10-01

    Temporomandibular ankylosis is a disabling condition that affects hygiene and cosmetic appearance. Several interpositional grafts such as meniscus, muscle, fascia, skin, cartilage, fat, dura, alloplastic materials and xenografts have been used to prevent recurrence of ankylosis. We studied the advantages and disadvantages of dermis fat graft as an interposition material after arthroplasty and compared it with temporalis fascia interposition. Seventeen patients with temporomandibular ankylosis involving 20 joints were randomly divided into two groups; the first group had operations for interposition of dermis-fat graft that was taken from the groin. Patients in control group had operations to interpose temporalis fascia and muscle from the same surgical site. All were assessed by age, sex, etiology, clinical features and post surgical complications. The groups were matched in age and the male: female ratio was 0.89:1.The median duration of ankylosis was 7.3 (range 2-11) years. Postoperative and follow up interincisal mouth opening was satisfactory with good healing of the dermis-fat graft donor site. We conclude that the use of dermis fat grafts has minimal donor site morbidity, and is a safe and effective interposition material to prevent the recurrence of temporomandibular ankylosis.

  20. Comparative Evaluation of Mastoid Cavity Obliteration by Vascularised Temporalis Myofascial Flap and Deep Temporal Fascial-Periosteal Flap in Canal Wall Down Mastoidectomy

    PubMed Central

    Sharma, Dinesh Kumar; Singh, Jagdeepak

    2016-01-01

    Introduction A consensus is emerging amongst otologists that obliteration of the mastoid cavity that results after modified radical mastoidectomy is a sound option to prevent cavity related problems such as otorrhoea, infection, granulation tissue and hearing loss. A variety of techniques have been proposed to perform the obliteration. Aim The present study aimed to compare the conventional method of mastoid cavity obliteration by vascularised temporalis myofascial flap with deep temporal fascial-periosteal flap in canal wall down mastoidectomy. Materials and Methods The prospective study (conducted between July 2012 and August 2013) randomly assigned patients with evidence of attico-antral disease to two groups (20 in each group). After canal wall down mastoidectomy, a superior based vascularised temporalis myofascial flap was used to obliterate the resultant mastoid cavity in group 1 patients and an inferior based deep temporal fascial-periosteal flap was used in group 2 patients for the cavity obliteration. They were then followed up till day 90. Results Cavity obliteration was better in group 2 (90%) as compared to group 1 (80%). Similarly, the final status of epithelisation of cavity at 90th day was clinically superior in patients of group 2 (85%) as compared to group 1 (75%). However, these difference were not statistically significant. Conclusion The clinical superiority of the results with temporal fascial-periosteal flap can be attributed to less frequent complications (partial obliteration and epithelisation of resultant mastoid cavities, residual perforation and persistent ear discharge) as compared to myofascial flap. PMID:28208893

  1. Pain and intramuscular release of algesic substances in the masseter muscle after experimental tooth-clenching exercises in healthy subjects.

    PubMed

    Dawson, Andreas; Ghafouri, Bijar; Gerdle, Björn; List, Thomas; Svensson, Peter; Ernberg, Malin

    2013-01-01

    To investigate whether experimental tooth clenching leads to a release of algesic substances in the masseter muscle. Thirty healthy subjects (16 females, 14 males) participated. During two sessions, separated by at least 1 week, intramuscular microdialysis was performed to collect masseter muscle 5-hydroxytryptamine (5-HT) and glutamate as well as the metabolic markers pyruvate and lactate. Two hours after the start of microdialysis, participants were randomized to a 20-min repetitive experimental tooth-clenching task (50% of maximal voluntary contraction) or a control session (no clenching). Pain and fatigue were measured throughout. The Friedman and Wilcoxon tests were used for statistical analyses. No alterations were observed in the concentrations of 5-HT, glutamate, pyruvate, and lactate over time in the clenching or control session, or between sessions at various time points. Pain (P < .01) and fatigue (P < .01) increased significantly over time in the clenching session and were significantly higher after clenching than in the control session (P < .01). Low levels of pain and fatigue developed with this experimental tooth-clenching model, but they were not associated with an altered release of 5-HT, glutamate, lactate, or pyruvate. More research is required to elucidate the peripheral release of algesic substances in response to tooth clenching.

  2. Effects of an occlusal splint on integrated electromyography of masseter muscle in experimental tooth clenching in man.

    PubMed

    Christensen, L V

    1980-07-01

    Six male subjects exercised maximal voluntary tooth clenching until fatigue appeared in the masseter muscle and until pains and exhaustion of this muscle could no longer be endured; that is, the fatigue threshold and the pain tolerance of the muscle were determined in seconds. An occlusal splint was inserted and the clenching exercises were repeated. During these exercises, and also during 10s of clenching, the electrical activity in the masseter muscle was recorded by bipolar surface electrodes and linearly integrated. Use of the splint did not result in significant changes in the subjective sensations of onset of fatigue and endurance of pain. As the periods of clenching increased, after insertion of the splint, the electrical activity decreased consistently, and use of the splint caused a significant decrease in the electrical activity of the pain tolerance test. As induced by the splint, there was no orderly pattern in changes of the fatigue thresholds and pain tolerances in relation to changes in the electrical activities of these parameters. The mode of action of the splint, in reducing the muscle activity, might have been that of stretching the elevator jaw muscles beyond their resting length.

  3. [Frequency analysis of the EMG power spectrum of the anterior temporal and masseter muscles in children and adults].

    PubMed

    Takarada, T; Alvarado Larrinaga, G; Nishida, F; Nishino, M

    1989-01-01

    For the investigation of the functional change of the masticatory muscles along with growth and development, the frequency analysis of the EMG power spectrum was carried out. The subjects were 6 children (5 males and 1 female) with full deciduous dentition (Hellman's dental age IIA) aged 4.5 +/- 0.2 years and 6 adults (4 males and 2 females) with full permanent dentition aged 27.7 +/- 3.8 years. EMG signals were recorded bilaterally by means of bipolar silver surface electrodes from the anterior temporal and masseter muscles when the subjects were chewing chewing gum or performing maximum clenches in the intercuspal position. A fast Fourier transform (FFT) algorithm was used to obtain the power spectrum of the EMG signal. As the total power value from 62.5 to 1000 Hz was 100 per cent, the mean frequencies at 25, 50, 75 and 90 per cent of the cumulative power were calculated. The results were as follows: 1. The mean frequencies at each ratio of the cumulative power were age-dependent and EMG power spectrum patterns significantly shifted to lower frequencies in the muscles of the adults. 2. No statistically significant differences between the chewing and clenching, the anterior temporal and masseter muscle and the left and right side were observed in each group.

  4. Location of the neuromuscular junction of the human masseter muscle estimated from the low frequency component of the surface electromyogram.

    PubMed

    Kumai, Toshifumi

    2005-02-01

    The position of the neuromuscular junction of the human masseter muscle has estimated from the low frequency component of the surface electromyogram. Monopolar surface electromyograms were recorded in response to clenching from eight sites with the reference electrode placed on the tip of the nose in six healthy male subjects. Component of the slow wave was separated from the raw recordings using digital filter, and the difference of the polarity and magnitude with the sites was examined. The base line of the recordings deflected either negatively or positively depending on the recording sites. These deflections coincided with bursts of muscular action potentials. Deflection of the slow wave component was largely negative over the inferior masseter close to the mandibular ramus but shifted to positive over the superior part. The greatest magnitude of the muscular action potential coincided with the most negative deflection of the slow wave. The phase of the muscular action potential burst also reversed near the site of the polarity change of the slow wave. These findings suggest that the slow wave, as detected by this method, originates mainly from the synaptic potential at the meuromuscular junction and that this is located on the inferior part of the muscle close to the mandibular ramus.

  5. The electrical activity of the temporal and masseter muscles in patients with TMD and unilateral posterior crossbite.

    PubMed

    Woźniak, Krzysztof; Szyszka-Sommerfeld, Liliana; Lichota, Damian

    2015-01-01

    The aim of this study was to assess the influence of unilateral posterior crossbite on the electrical activity of the temporal and masseter muscles in patients with subjective symptoms of temporomandibular dysfunctions (TMD). The sample consisted of 50 patients (22 female and 28 male) aged 18.4 to 26.3 years (mean 20.84, SD 1.14) with subjective symptoms of TMD and unilateral posterior crossbite malocclusion and 100 patients without subjective symptoms of TMD and malocclusion (54 female and 46 male) aged between 18.4 and 28.7 years (mean 21.42, SD 1.06). The anamnestic interviews were conducted according to a three-point anamnestic index of temporomandibular dysfunction (Ai). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Recordings were carried out in the mandibular rest position and during maximum voluntary contraction (MVC). Analysis of the results of the EMG recordings confirmed the influence of unilateral posterior crossbite on variations in spontaneous muscle activity in the mandibular rest position and maximum voluntary contraction. In addition, there was a significant increase in the Asymmetry Index (As) and Torque Coefficient (Tc), responsible for a laterodeviating effect on the mandible caused by unbalanced right and left masseter and temporal muscles.

  6. The Electrical Activity of the Temporal and Masseter Muscles in Patients with TMD and Unilateral Posterior Crossbite

    PubMed Central

    Woźniak, Krzysztof; Lichota, Damian

    2015-01-01

    The aim of this study was to assess the influence of unilateral posterior crossbite on the electrical activity of the temporal and masseter muscles in patients with subjective symptoms of temporomandibular dysfunctions (TMD). The sample consisted of 50 patients (22 female and 28 male) aged 18.4 to 26.3 years (mean 20.84, SD 1.14) with subjective symptoms of TMD and unilateral posterior crossbite malocclusion and 100 patients without subjective symptoms of TMD and malocclusion (54 female and 46 male) aged between 18.4 and 28.7 years (mean 21.42, SD 1.06). The anamnestic interviews were conducted according to a three-point anamnestic index of temporomandibular dysfunction (Ai). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany). Recordings were carried out in the mandibular rest position and during maximum voluntary contraction (MVC). Analysis of the results of the EMG recordings confirmed the influence of unilateral posterior crossbite on variations in spontaneous muscle activity in the mandibular rest position and maximum voluntary contraction. In addition, there was a significant increase in the Asymmetry Index (As) and Torque Coefficient (Tc), responsible for a laterodeviating effect on the mandible caused by unbalanced right and left masseter and temporal muscles. PMID:25883948

  7. Comments on standardization of reflex measurements in human masseter muscle, including silent periods.

    PubMed

    van der Glas, H W; van Steenberghe, D

    1989-11-01

    The following comments are given on the guidelines suggested by Türker (1988) for studies on oral reflexes using the surface EMG of the masseter muscles in man, including the silent period. (i) Attention should not be confined to electrical stimulation since mechanoreceptors in the periodontium, especially in the periodontal ligament, can only be activated by mechanical stimulation of a tooth. Furthermore, different modes of stimulation and stimulation sites do not yield equivalent reflex complexes. Weak and transient mechanical stimulation of a tooth while clenching at a low level of 5 or 10% MVC is a selective model (89%) to study the influence of periodontal receptors. (ii) Statistical criteria should be applied on rectified and averaged EMG records to prevent any subjective bias in the measurements of reflex variables. Whether a period of increased EMG activity is due to clustering of action potentials of motor units firing of which was delayed by a preceding inhibition, or to a real excitatory influence, can be assessed by applying statistical criteria on averaged and subsequently rectified records. (iii) The clenching level should be less than 25% of MVC to avoid muscle fatigue, and to elicit pronounced reflexes with a weak and therefore more selective stimulus. (iv) The stimulus intensity should be much less than six times the threshold if selectivity for mechanoreceptors is desired. Furthermore, periods of increased activity in surface EMG resulting from a weak stimulus are probably due to real excitatory influences and not to clustering of motor unit action potentials after an inhibition. (v) Jaw separation and the use of a force transducer are not always advantageous. If mechanical stimulation is applied to a tooth, clenching in full habitual occlusion causes a complete suppression of the influence of muscle spindles. A shift in activity between the various elevator muscles, and hence a change in activity of the muscle studied, may occur during an

  8. Comparison of clinical marking and ultrasound-guided injection of Botulinum type A toxin into the masseter muscles for treating bruxism and its cosmetic effects.

    PubMed

    Quezada-Gaon, Natacha; Wortsman, Ximena; Peñaloza, Osvaldo; Carrasco, Juan Eduardo

    2016-09-01

    Botulinum toxin type A has been used for treating the hypertrophy of the masseter muscles and its cosmetic effects. Ultrasound is increasingly used in dermatology, along with the guidance of mini-invasive procedures. To evaluate the role of ultrasound for guiding the application of Botulinum A toxin in patients with cosmetic alterations due to bruxism, correlate the clinical landmarks with the ultrasound findings, and study the effect on the symptoms, cosmetics, and quality of life. Twenty individuals with bruxism and cosmetic alterations underwent an ultrasound-guided injection of Botulinum toxin type A in each masseter muscle. Clinical and ultrasound marking of the procedure was compared. Clinical and sonographic evaluation was performed at the time of injection and 3 months later. Ten normal individuals underwent ultrasound of the masseter muscles as a control group. Up to 65% of individuals showed anatomical variants of the salivary glands. The method for clinically marking the skin showed a frequently erroneous location of the anterior point (up to 40% of cases) that was proven by ultrasound to be out of the muscle. In 20% of cases, ultrasound showed that the needle should be longer to enter the muscle. After injection, most of the patients demonstrated a decrease of the symptoms and cosmetic and quality of life improvements. Ultrasound can be a potent tool for guiding the injection of Botulinum toxin into the masseter muscles. It may contribute to a more personalized procedure, better cosmetic results, and help to avoid potential complications. © 2016 Wiley Periodicals, Inc.

  9. Effect of pain on the timing pattern of masseter muscle activity during the open-close-clench cycle in the migraine without aura and tension type headaches

    PubMed Central

    Talebian, Saeed; Hashemirad, Fahimeh; Ghaffarpour, Majid

    2012-01-01

    Background The existence of a pathophysiological link between headaches and muscle activity pattern is still being debated. The purpose of this study was to investigate the effect of pain on the timing pattern of the masseter muscle in patients with tension-type headache (TTH) and migraine without aura (MOA). Methods 57 women (22 controls, 19 MOA and 16 TTH) participated in the study. The electromyographic (EMG) activity of masseter during the open-close-clench cycle (OCC) was recorded in the interictal and ictal stages. Results In the interictal stage, the results showed no significant difference in EMG activity between patients and control groups. However, masseter muscles in subjects with TTH (both sides) and in MOA patients (left side) activated significantly earlier than the control in the ictal stage. The duration of left masseter was also significantly greater in the TTH than in the control group (P < 0.05). Conclusion The findings of this study showed that activity pattern of masticatory muscles in headaches patients were affected by existence of pain. Furthermore, this study confirmed that temporal variables of EMG such as onset and duration rather than amplitude could be more reliable to identify altered activity pattern of muscles. PMID:24250884

  10. Short-term effects of dry needling of active myofascial trigger points in the masseter muscle in patients with temporomandibular disorders.

    PubMed

    Fernández-Carnero, Josué; La Touche, Roy; Ortega-Santiago, Ricardo; Galan-del-Rio, Fernando; Pesquera, Jorge; Ge, Hong-You; Fernández-de-Las-Peñas, César

    2010-01-01

    To investigate the effects of dry needling over active trigger points (TrPs) in the masseter muscle in patients with temporomandibular disorders (TMD). Twelve females, aged 20 to 41 years old (mean = 25, standard deviation +/- 6 years) diagnosed with myofascial TMD were recruited. Each patient attended two treatment sessions on two separate days and received one intervention assigned in a random fashion, at each visit: deep dry needling (experimental) or sham dry needling (placebo) at the most painful point on the masseter muscle TrP. Pressure pain threshold (PPT) over the masseter muscle TrP and the mandibular condyle and pain-free active jaw opening were assessed pre- and 5 minutes postintervention by an examiner blinded to the treatment allocation of the subject. A two-way repeated-measures analysis of variance (ANOVA) with intervention as the between-subjects variable and time as the within-subjects variable was used to examine the effects of the intervention. The ANOVA detected a significant interaction between intervention and time for PPT levels in the masseter muscle (F = 62.5; P < .001) and condyle (F = 50.4; P < .001), and pain-free active mouth opening (F = 34.9; P < .001). Subjects showed greater improvements in all the outcomes when receiving the deep dry needling compared to the sham dry needling (P < .001). The application of dry needling into active TrPs in the masseter muscle induced significant increases in PPT levels and maximal jaw opening when compared to the sham dry needling in patients with myofascial TMD.

  11. Efficacy of photobiomodulation therapy on masseter thickness and oral health-related quality of life in children with spastic cerebral palsy.

    PubMed

    Santos, Maria Teresa Botti Rodrigues; Nascimento, Karla Santos; Carazzato, Simone; Barros, Alina Oliveira; Mendes, Fausto Medeiros; Diniz, Michele Baffi

    2017-08-01

    The study aimed to evaluate the efficacy of photobiomodulation therapy (PBMT) on bilateral masseter muscle thickness and amplitude of mouth opening in children with spastic cerebral palsy (CP), and the impact on their oral health-related quality of life (OHRQOL). Three groups were included: experimental CP group (EG: n = 26 with oral complaints), positive control CP group (PCG: n = 26 without complaints), and negative control group (NCG: n = 26 without CP). In the EG, the masseter muscles on both sides were irradiated with an infrared low-level Ga-Al-As laser (λ = 808 ± 3 nm, 120 mW) using a 3 J/cm(2) energy dose per site, with a 20 s exposure time per site (spot area: 4 mm(2); irradiance: 3 W/cm(2); energy delivery per point: 2.4 J) six times over six consecutive weeks. Masseter thickness, assessed through ultrasonography, and the amplitude of mouth opening were measured in the EG before and after six applications of PBMT and once in the PCG and NCG. The Parental-Caregiver Perception Questionnaire (P-CPQ) was used to evaluate OHRQOL. ANOVA, chi-square, t tests, and multilevel linear regression were used for statistical analysis. In the EG, the study results revealed average increments of 0.77 (0.08) millimeter in masseter thickness (P < 0.05) and 7.39 (0.58) millimeter for mouth opening (P < 0.05) and reduction in all P-CPQ domains (P < 0.001), except for social well-being. The six applications of PBMT increased masseter thickness and mouth opening amplitude and reduced the impact of spastic CP on OHRQOL.

  12. Histological changes and changes in the myosin mRNA content of the porcine masticatory muscles after masseter treatment with botulinum toxin A.

    PubMed

    Gedrange, T; Gredes, T; Spassov, A; Mai, R; Kuhn, D U; Dominiak, M; Kunert-Keil, C

    2013-04-01

    Botulinum toxin A (Botox) is increasingly used for treatment of muscle hyperfunction. For a better understanding of the possible morphologic and chewing changes in patients induced by a therapy with Botox, muscle fiber and myosin heavy chain (MyHC) mRNA alterations were examined in this animal study. The investigation was carried out on 14-week-old pigs (seven treated animals, eight controls; calculated animal size with a power of 0.5). To initialise the total immobilisation of the right masseter, the Botox injection was distributed into ten areas. After a 56-day period, muscle tissue was taken from the left and right side of the masseter (three regions), temporal (two regions), medial pterygoid and geniohyoid muscles using a standardized method. The muscle fiber cross sections were examined immunohistochemically. Fiber staining was accomplished with antibodies to specific MyHC isoforms. The MyHC mRNA changes were analysed using real-time RT-PCR. Muscles adapt to such stress by changing fiber types and MyHC mRNA content. Paralysed masseters display atrophic changes while other masticatory muscles show hypertrophic changes. The results indicated that the typical distributions of type IIa und IIb fiber types in masticatory muscles were increased in the masseter muscles due to Botox application. On the other hand, the masseters without Botox in the treated group showed a significant increase of type I MyHC. Application of Botox may lead to uncontrolled structural changes in affected and unaffected muscles. Treatment of muscle hypertrophy with Botox may cause muscle imbalance.

  13. Masseter-to-facial nerve transfer: a highly effective technique for facial reanimation after acoustic neuroma resection.

    PubMed

    Wang, Wei; Yang, Chuan; Li, Qingfeng; Li, Wei; Yang, Xianxian; Zhang, Yi Xin

    2014-09-01

    Masseter-to-facial nerve transfer is a new procedure for patients who acquire a proximal injury to the facial nerve. This article reports that this procedure is effective and associated with minimal morbidities. From November 2010 to February 2013, 16 patients underwent a masseter-to-facial nerve transfer. Their denervation periods varied from 2 to 18 months, with an average of 10.1±4.1 months. Their ages varied from 22 to 70 years, with an average of 34.7±15.4 years. The etiology of denervation was tumor resection in the cerebellopontine angle in all cases. All of the patients were followed up several times. The outcomes of the first follow-up at 3 months postoperatively and the last follow-up at a minimum 12 months postoperatively were documented. Using Terzis' and Metha's scales, the smile outcomes and synkinetic movements as visualized using standardized videos were graded preoperatively and postoperatively. The periods between the operation and the onset of mimetic muscle contraction were documented. A questionnaire was administered to evaluate the donor-site morbidity and the ability to smile without biting. The final outcomes for smile function were as follows: 9 patients (56.3%) had excellent or good function, 5 patients (31.3%) had moderate function, and 2 patients (12.5%) had poor function. There was significant improvement between the preoperative and postoperative time points and between the outcomes at the first and last follow-ups (P<0.05). Additionally, 13 (81.3%) patients had the ability to smile without biting 12 months postoperatively. The onset of muscle motion varied from 56 to 365 days and was positively correlated with age in the group of patients older than 40 years and negatively correlated with the outcome of the first follow-up. Four (25%) patients complained of concavity at the parotideomasseteric region, but none complained of disturbance in food intake. Synkinetic movements were observed in all patients and were rated as mild. The

  14. Sarcopenia as a predictor of mortality in elderly blunt trauma patients: Comparing the masseter to the psoas using computed tomography.

    PubMed

    Wallace, James D; Calvo, Richard Y; Lewis, Paul R; Brill, Jason B; Shackford, Steven R; Sise, Michael J; Sise, C Beth; Bansal, Vishal

    2017-01-01

    Sarcopenia, or age-related loss of muscle mass, is measurable by computed tomography (CT). In elderly trauma patients, increased mortality is associated with decreased psoas muscle cross-sectional area (P-Area) on abdominal CT. Fall is the leading cause of injury in the elderly, and head CT is more often obtained. Masseter muscle cross-sectional area (M-Area) is readily measured on head CT. Hypothesizing that M-Area is a satisfactory surrogate for P-Area, we compared the two as markers of sarcopenia and increased mortality in elderly trauma patients. All blunt-injured patients aged 65 years or older admitted to our trauma center during 2010 were included. Two-year postdischarge mortality was identified by matching records to county, state, and national death indices. Bilateral M-Area was measured on admission head CT at 2 cm below the zygomatic arch. Bilateral P-Area was measured on abdominal CT at the fourth vertebral body. Average M-Area and P-Area values were calculated for each patient. Cox proportional hazards models evaluated the relationship of M-Area and P-Area with mortality. Model predictive performance was calculated using concordance statistics. Among 487 patients, 357 with M-Area and 226 with P-Area were identified. Females had smaller M-Area (3.43 cm vs 4.18 cm; p < 0.050) and P-Area (6.50 cm vs 10.9 cm; p < 0.050) than males. Masseter muscle cross-sectional area correlated with P-Area (rho, 0.38; p < 0.001). Adjusted Cox regression models revealed decreased survival associated with declining M-Area (hazard ratio, 0.76; 95% confidence interval, 0.60-0.96) and P-Area (hazard ratio, 0.68; 95% confidence interval, 0.46-1.00). Masseter muscle cross-sectional area and P-Area discriminated equally well in best-fit models. In elderly trauma patients, M-Area is an equally valid and more readily available marker of sarcopenia and 2-year mortality than P-Area. Future study should validate M-Area as a metric to identify at-risk patients who may benefit from

  15. 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.

  16. Comparison of results of graft uptake using tragal cartilage perichondrium composite graft versus temporalis fascia in patients undergoing surgery for chronic otitis media - squamous type.

    PubMed

    Khalilullah, S; Shah, Shankar P; Yadav, D; Shrivastav, R P; Bhattarai, H

    2016-08-02

    To assess, analyze and compare the results of graft uptake using Tragal Cartilage-Perichondrium Composite (TCPC) graft with Temporalis Fascia (TF) graft in patients who undergoing surgery for chronic otitis media - squamous type. Patients aged 13 years and above with diagnosis of chronic otitis media - squamous type undergoing modified radical mastoidectomy, either primary or revision surgery with grafting of tympanic membrane (TM) and patients undergoing excision of postero-superior retraction pocket (PSRP) were included in this study. Patients were divided in two groups: Group A-patients undergoing TCPC graft and Group B -patients undergoing TF graft. Graft uptake results were assessed between 8-12 weeks of surgery. In both Groups there were 30 patients each. In Group A successful graft uptake was seen in 27 patients (90 %) and failure of graft uptake was seen in 3 patients(10 %). In Group B successful graft uptake was seen in 28 patients (93.3 %) and failure in 2 patients (6.67 %).Out of the total 60 patients, 11 patients had PSRP. All 6 patients with PSRP in Group A had successful graft uptake and no retraction. Among the 5 patients with PSRP in Group B all patients had sucessful graft uptake, however, in 2 patients retraction of the tympanic membrane was seen similar to the preoperative findings. There was no statistical difference (p = 0.433) between the use of temporalis fascia or tragal cartilage perichondrium in patients undergoing surgery for chronic otitis media - squamous type.

  17. Functional interactions between NMDA receptors and TRPV1 in trigeminal sensory neurons mediate mechanical hyperalgesia in the rat masseter muscle

    PubMed Central

    Lee, Jongseok; Saloman, Jami L.; Weiland, Gustave; Auh, Q-Schick; Chung, Man-Kyo; Ro, Jin Y.

    2012-01-01

    NMDA and TRPV1 receptors that are expressed in sensory neurons have been independently demonstrated to play important roles in peripheral pain mechanisms. In the present study, we investigated whether the two receptor-channel systems form a functional complex that provides the basis for the development of mechanical hyperalgesia. In the masseter muscle, direct application of NMDA induced a time dependent increase in mechanical sensitivity, which was significantly blocked when the muscle was pretreated with a specific TRPV1 antagonist, AMG9810. The NR1 subunit of the NMDA receptor and TRPV1 were co-expressed in 32% of masseter afferents in trigeminal ganglia (TG). Furthermore, NR1 and NR2B formed protein-protein complexes with TRPV1 in TG as demonstrated by co-immunoprecipitation experiments. Calcium imaging analyses further corroborated that NMDA and TRPV1 receptors functionally interact. In TG culture, application of NMDA resulted in phosphorylation of serine, but not threonine or tyrosine, residues of TRPV1 in a time course similar to that of the development of NMDA-induced mechanical hyperalgesia. The NMDA-induced phosphorylation was significantly attenuated by CaMKII and PKC inhibitors, but not by a PKA inhibitor. Consistent with the biochemical data, the NMDA-induced mechanical hyperalgesia was also effectively blocked when the muscle was pretreated with a CaMKII or PKC inhibitor. Thus, NMDA receptors and TRPV1 functionally interact via CaMKII and PKC signaling cascades and contribute to mechanical hyperalgesia. These data offer novel mechanisms by which two ligand-gated channels in sensory neurons interact and reinforce the notion that TRPV1 functions as a “signal integrator” under pathological conditions. PMID:22609428

  18. Smile reconstruction in adults with free muscle transfer innervated by the masseter motor nerve: effectiveness and cerebral adaptation.

    PubMed

    Manktelow, Ralph T; Tomat, Laura R; Zuker, Ron M; Chang, Mary

    2006-09-15

    This study assesses the ability of the masseter motor nerve-innervated microneurovascular muscle transfer to produce an effective smile in adult patients with bilateral and unilateral facial paralysis. The operation consists of a one-stage microneurovascular transfer of a portion of the gracilis muscle that is innervated with the masseter motor nerve. The muscle is inserted into the cheek and attached to the mouth to produce a smile. The outcomes assessed were the amount of movement of the transferred muscle; the aesthetic quality of the smile; the control, use, and spontaneity of the smile; and the functional effects on eating, drinking, and speech. The study included 27 patients aged 16 to 61 years who received 45 muscle transfers. All 45 muscle transfers developed movement. The commissure movement averaged 13.0 +/- 4.7 mm at an angle of 47 +/- 15 degrees above the horizontal, and the mid upper lip movement averaged 8.3 +/- 3.0 mm at 42 +/- 17 degrees. Age did not affect the amount of movement. Patients older than 50 years had the same amount of movement as patients younger than 26 years (p = 0.605). Ninety-six percent of patients were satisfied with their smile. A spontaneous smile, the ability to smile without thinking about it, occurred routinely in 59 percent and occasionally in 29 percent of patients. Eighty-five percent of patients learned to smile without biting. Age did not affect the degree of spontaneity of smiling or the patient's ability to smile without biting.

  19. Symmetry restoration at rest after masseter-to-facial nerve transfer: Is it as efficient as smile reanimation?

    PubMed

    Chen, Gang; Wang, Wenjin; Wang, Wei; Ding, Wei; Yang, Xianxian

    2017-06-14

    Masseter-to-facial nerve transfer is a highly efficient technique for reanimating paralyzed muscle and has been reported to restore facial symmetry at rest. However, no systematic studies have been performed, and the effects of preoperative droop oral commissure on postoperative symmetry at rest have rarely been reported. The authors retrospectively analyzed 35 patients with masseteric-facial nerve anastomosis and assessed the quality and quantity of the dynamic recovery and the oral commissure symmetry at rest. The dynamic and static effects were then compared. All of the patients' Terzis scores were increased post-operatively, and over half of the patients presented restored symmetrical smiles (Terzis scores of 4 or 5). The postoperative symmetry scale of oral commissure at rest improved in 18 of 35 patients. Both the mean postoperative AD-OCE (altitude difference of oral commissure excursion) and the postoperative AD-OCP (altitude difference of bilateral oral commissure position) were decreased compared to preoperative values. The preoperative symmetry had a significant effect on the postoperative AD-OCP. The effects of the dynamic and static symmetry improvements were transformed to a comparable factor 'α'. The dynamic α was significantly greater than static α. Masseter-to-facial nerve transfer is a reliable technique for smile reanimation. However, it has only a limited effect on the improvement of symmetry at rest. Assessing the preoperative symmetry of oral commissure at rest can be used to predict postoperative outcomes, and patients with severely droop oral commissure (symmetry scale III or IV) should receive static suspension.

  20. Relationship between dimensions of muscles of mastication (masseter and lateral pterygoid) and skeletal dimensions: study of 40 cases.

    PubMed

    Azaroual, Mohammed Faouzi; Fikri, Meriem; Abouqal, Redouan; Benyahya, Hicham; Zaoui, Fatima

    2014-03-01

    The masticatory muscles play an important part in determining the morphology of the facial skeleton. Skeletal typology and the characteristics of the masticatory muscles are closely linked. Several authors have studied muscle characteristics as related to facial typology. The aim of this work is to study the relationship between vertical and transverse skeletal dimensions and the dimensions (length, width and thickness) of two muscles of mastication, the masseter and the lateral pterygoid. Our study was based on CT-scan examinations of a sample composed of patients consulting the X-ray department of the Rabat-Salé Teaching Hospital, and for whom a CT-scan had been requested. Forty CT examinations of the skull, performed in the context of sinus explorations or pre-surgical work-ups in the radiology department of the Rabat-Salé Teaching Hospital, were selected for this study. The sample comprised 19 women and 21 men aged between 20 and 45, with a mean of 40.9 ± 12.8. A Siemens 32-row 64-slice spiral CT-scan device was used for spiral acquisition of data around the facial bones, with the mouth closed. The study was carried out in the parenchymal window for the muscle measurements, in the axial and coronal planes. Bone measurements were performed after 3D reconstruction in VRT mode. Our study showed that, for the masseter muscle, thickness is the dimension that correlates significantly with skeletal dimensions in the vertical, transverse and sagittal directions. For the lateral pterygoid muscle, length and width both present significant correlations with transverse skeletal dimensions. Analysis of these results shows that the dimensional characteristics of the masticatory muscles vary according to the vertical and transverse skeletal typology of the subjects concerned. Copyright © 2013. Published by Elsevier Masson SAS.

  1. Evaluation of Internal Echogenic Pattern of Masseter in Subjects with Myofascial Pain/ Myositis, Oral Submucous Fibrosis, Chewers, Bruxers and Healthy Individuals- A Preliminary Ultrasonographic Study

    PubMed Central

    Raghunandan Iyengar, Asha; Patil, Seema; Guddannanavar Karibasappa, Ganga; Beloor Vasudev, Subash; Kumar Joshi, Revan

    2016-01-01

    Statement of the Problem: The masseter is generally involved in myofascial pain, myositis, oral submucous fibrosis (OSMF), bruxism, and in subjects with habitual tobacco/arecanut chewing. In all the above conditions, changes in the internal echogenic pattern on ultrasonography of the muscle may be observed. Purpose: The present study aimed at evaluating the internal echogenic pattern of masseter by ultrasonography in subjects with various conditions affecting masster muscle. Materials and Method: The study subjects were categorized into 5 groups consisting of 20 subjects each with the following conditions; Group 1: myofascial pain or myositis, Group 2: oral submucous fibrosis (OSMF), Group 3: habitual chewing of tobacco/arecanut without OSMF, Group 4: bruxism. Group 5 consisted of 20 healthy subjects. An ultrasonographic examination of masseter was performed in all subjects and the echogenic pattern was classified into Types I, II and III. The images were examined by two observers and inter-observer variability was assessed. Differences in internal echogenic pattern between study groups and control group was evaluated using Chi- square test. Results: A good inter observer agreement was noted (k value= 0.8). An equal distribution of Types II and III echogenic pattern was noted in myofascial pain/myositis group. Type II was predominant in subjects with OSMF, habitual tobacco/arecanut chewing and bruxism. Type I was predominant in controls. The echogenic pattern differed significantly from controls in subjects with myofascial pain/myositis and OSMF (p=0.00001*, 0.0237* respectively), whereas in subjects with habitual tobacco/ arecanut chewing and bruxism, it did not differ significantly from controls (p=0.2482, 0.1223 respectively). Conclusion: Ultrasonographic examination of the echogenic pattern may help in understanding the nature of the disease process affecting the masseter muscle in various conditions. PMID:27942553

  2. Evaluation of Internal Echogenic Pattern of Masseter in Subjects with Myofascial Pain/ Myositis, Oral Submucous Fibrosis, Chewers, Bruxers and Healthy Individuals- A Preliminary Ultrasonographic Study.

    PubMed

    Raghunandan Iyengar, Asha; Patil, Seema; Guddannanavar Karibasappa, Ganga; Beloor Vasudev, Subash; Kumar Joshi, Revan

    2016-12-01

    The masseter is generally involved in myofascial pain, myositis, oral submucous fibrosis (OSMF), bruxism, and in subjects with habitual tobacco/arecanut chewing. In all the above conditions, changes in the internal echogenic pattern on ultrasonography of the muscle may be observed. The present study aimed at evaluating the internal echogenic pattern of masseter by ultrasonography in subjects with various conditions affecting masster muscle. The study subjects were categorized into 5 groups consisting of 20 subjects each with the following conditions; Group 1: myofascial pain or myositis, Group 2: oral submucous fibrosis (OSMF), Group 3: habitual chewing of tobacco/arecanut without OSMF, Group 4: bruxism. Group 5 consisted of 20 healthy subjects. An ultrasonographic examination of masseter was performed in all subjects and the echogenic pattern was classified into Types I, II and III. The images were examined by two observers and inter-observer variability was assessed. Differences in internal echogenic pattern between study groups and control group was evaluated using Chi- square test. A good inter observer agreement was noted (k value= 0.8). An equal distribution of Types II and III echogenic pattern was noted in myofascial pain/myositis group. Type II was predominant in subjects with OSMF, habitual tobacco/arecanut chewing and bruxism. Type I was predominant in controls. The echogenic pattern differed significantly from controls in subjects with myofascial pain/myositis and OSMF (p=0.00001*, 0.0237* respectively), whereas in subjects with habitual tobacco/ arecanut chewing and bruxism, it did not differ significantly from controls (p=0.2482, 0.1223 respectively). Ultrasonographic examination of the echogenic pattern may help in understanding the nature of the disease process affecting the masseter muscle in various conditions.

  3. Effect of single dose intramuscular methylprednisolone injection into the masseter muscle on the surgical extraction of impacted lower third molars: a randomized controlled trial.

    PubMed

    Vyas, N; Agarwal, S; Shah, N; Patel, D; Aapaliya, P

    2014-01-01

    Lower impacted third molar surgical extraction usually causes post-surgical sequelae like pain, trismus and swelling as a result of postoperative inflammatory response. The aim of this study was to evaluate and compare the efficacy of single dose 40-mg (1 cc) of methylprednisolone acetate, injected into the masseter muscle, preoperatively one hour before the surgery or post-operatively, immediately following the surgical removal of impacted lower third molars, in controlling most common postoperative sequelae, i.e. trismus, pain and swelling of facial soft tissue. A randomized control study was done of 60 patients. Each patient was categorized in two groups, group I and group II, according to the time of receiving methylprednisolone acetate. Group I was injected 40 mg of methylprednisolone acetate into the masseter muscle via the intrabuccal approach, one hour before the surgery. Group II was injected 40 mg of methylprednisolone acetate into the masseter muscle via the intrabuccal approach, immediately after suturing of the surgical wound. The washout period was one month after the first operation. Evaluation were made of postoperative pain, trismus and swelling. The numeric pain scale (NPS) was used for pain assessment. When the patients were administered methylprednisolone acetate preoperatively, showed superior results in terms of oral aperture, pain and all the facial swelling parameters, with statistically significant differences versus the postoperatively administered methylprednisolone acetate (p < 0.05). A single dose of 40 mg (1 cc) methylprednisolone acetate injected into the masseter muscle preoperatively is more effective in reducing pain, trismus and swelling, when compared to that administered postoperatively.

  4. [Alteration of metabolic characteristics on the masseter muscle fiber of unilateral chewing rats and its adenosine monophosphate activated protein kinase regulatory mechanism].

    PubMed

    Andi, Shi; Lin, Zeng; Jing, Liu

    2017-06-01

    This study aims to determine the influence of unilateral chewing on metabolic characteristics of masseter muscle fibers in rats and the regulatory effect of an adenosine monophosphate activated protein kinase (AMPK) signal pathway on metabolism. Rats were submitted to exodontia of all the right maxillary molars and divided into 2, 4, 6, and 8 weeks groups, and corresponding control groups were set as well. Sections were stained by nicotine adenine dinucleotide tetrazolim reductase(NADH-TRase) to demonstrate the types, proportion, and density of masseter muscle fibers. AMPKα1 and p-AMPK(Thr172) levels in bilateral masseter muscles were detected by Western blot. In the 2-week group, the percentage of dark fibers augmented in the ipsilateral side, whereas the percentage of intermediary fibers in the contralateral side was increased accompanied by a decrease of light fibers, compared with the control group (P<0.05). The percentage of dark fibers was increased in the bilateral sides, whereas the percentage of dark fiber in the ipsilateral sides surpassed that of the contralateral sides in the 4, 6, and 8-week groups. The percentage of intermediary fibers was decreased in the bilateral sides in the 6 and 8-week groups (P<0.05). The percentage of light fibers was reduced in the ipsilateral sides in the 8-week group, whereas no alteration was observed in contralateral sides (P>0.05). In the ipsilateral sides, p-AMPK (Thr172)/AMPKα1 levels were increased in the 2 and 4-week groups (P<0.05), whereas no change was observed in the contralateral sides in either group (P>0.05). Unilateral chewing increases the oxidative metabolic ability in bilateral masseter muscle fibers especially in the non-working side accompanied with change of muscle fiber types. The improvement of aerobic metabolism ability is related to the AMPK signal pathway.
.

  5. Potential clinical application of masseter and temporal muscle massage treatment using an oral rehabilitation robot in temporomandibular disorder patients with myofascial pain.

    PubMed

    Ariji, Yoshiko; Nakayama, Miwa; Nishiyama, Wataru; Ogi, Nobumi; Sakuma, Shigemitsu; Katsumata, Akitoshi; Kurita, Kenichi; Ariji, Eiichiro

    2014-11-11

    Objectives: To investigate the safety, suitable treatment regimen, and efficacy of masseter and temporal muscle massage treatment using an oral rehabilitation robot. Methods: Forty-one temporomandibular disorder (TMD) patients with myofascial pain (8 men, 33 women, median age: 46 years) were enrolled. The safety, suitable massage regimen, and efficacy of this treatment were investigated. Changes in masseter muscle thickness were evaluated on sonograms. Results: No adverse events occurred with any of the treatment sessions. Suitable massage was at pressure of 10 N for 16 minutes. Five sessions were performed every 2 weeks. Total duration of treatment was 9·5 weeks in median. Massage treatment was effective in 70·3% of patients. Masseter muscle thickness decreased with treatment in the therapy-effective group. Conclusion: This study confirmed the safety of massage treatment, and established a suitable regimen. Massage was effective in 70·3% of patients and appeared to have a potential as one of the effective treatments for myofascial pain.

  6. The effect of sensory level electrical stimulation of the masseter muscle in early stroke patients with dysphagia: A randomized controlled study.

    PubMed

    Umay, Ebru K; Yaylaci, Atilay; Saylam, Guleser; Gundogdu, Ibrahim; Gurcay, Eda; Akcapinar, Dehen; Kirac, Zeynep

    2017-01-01

    Dysphagia is a serious cause of morbidity and mortality in stroke patients. As the first study in literature, we aimed to evaluate the effects of sensory-level electrical stimulation (SES) to bilateral masseter muscles in early stroke patients with dysphagia. This study was conducted at the Physical Medicine and Rehabilitation Clinic of our hospital between 2013 and 2015. Ninety-eight patients with dysphagia within the first month after ischemic stroke were included in this study. Patients were evaluated by bedside screening tests (Bedside Dysphagia Score, Neurological Examination Dysphagia Score, Total Dysphagia Score, and Mann Assessment of Swallowing Ability test) and by flexible fibreoptic endoscopic evaluation of swallowing (FEES) methods. All patients were included in a traditional swallowing therapy. Patients were divided into two groups, namely the "stimulation group" and "sham group." SES was applied to bilateral masseter muscles. Evaluation parameters were compared between the groups before and after therapy. The Friedman test, Wilcoxon Signed Rank test, Mann-Whitney U test, and Fisher exact test were used in this study. There was a significant improvement in dysphagia severity scores evaluated by bedside screening tests and FEES in cognitive and total functionality levels except in motor functional independence level in the stimulation group. In the sham group, there were no significant changes in the evaluation parameters. SES applied to bilateral masseter muscles may provide an effective treatment for both dysphagia and cognitive function in early stroke patients.

  7. TMJ inflammation increases Fos expression in the nucleus raphe magnus induced by subsequent formalin injection of the masseter or hindpaw of rats.

    PubMed

    Oh, Sang-Hoon; Imbe, Hiroki; Iwai-Liao, Yasutomo

    2006-08-01

    The study was designed to examine the effect of persistent temporomandibular joint (TMJ) inflammation on neuronal activation in the descending pain modulatory system in response to noxious stimulus. Formalin was injected into the left masseter muscle or hindpaw of rats 10 days after injection of the left TMJ with saline or complete Freund's adjuvant (CFA). The results showed that 10-day persistent TMJ inflammation (induced by CFA) alone did not induce a significant increase in Fos-like immunoreactive (Fos-LI) neurons in the rostral ventromedial medulla (RVM) or locus coeruleus (LC), but that formalin injection of the masseter muscle or hindpaw induced a significant increase in Fos-LI neurons in the RVM and LC of rats with and without TMJ inflammation (P < 0.05). However, persistent TMJ inflammation significantly increased Fos-LI neurons in the nucleus raphe magnus (NRM) induced by subsequent formalin injection of the masseter muscle and hindpaw (70.2% increase and 53.8% increase, respectively, over the control TMJ-saline-injected rats; P < 0.05). The results suggest that persistent TMJ inflammation increases neuronal activity, in particularly in the NRM, by the plastic change of the descending pain modulatory system after ipsilateral application of a noxious stimulus to either orofacial area or a spatially remote body area.

  8. The power features of Masseter muscle activity in tension-type and migraine without aura headache during open-close clench cycles.

    PubMed

    Alizadeh Savareh, Behrouz; Ghanjal, Ali; Bashiri, Azadeh; Motaqi, Monireh; Hatef, Boshra

    2017-01-01

    Different types of headaches and TMJ click influence the masseter muscle activity. The aim of this study was to assess the trend of energy level of the electromyography (EMG) activity of the masseter muscle during open-close clench cycles in migraine without aura (MOA) and tension-type headache (TTH) with or without TMJ click. Twenty-five women with MOA and twenty four women with TTH participated in the study. They matched with 25 healthy subjects, in terms of class of occlusion and prevalence of temporomandibular joint (TMJ) with click. The EMG of both masseter muscles were recorded during open-close clench cycles at a rate of 80 cycles per minute for 15 seconds. The mouth opening was restricted to two centimeters by mandibular motion frame. Signal processing steps have been done on the EMG as: noise removing, smoothing, feature extraction, and statistical analyzing. The six statistical parameters of energy computed were mean, Variance, Skewness, Kurtosis, and first and second half energy over all signal energy. A three-way ANOVA indicated that during all the cycles, the mean of energy was more and there was a delay in showing the peak of energy in the masseter of the left side with clicked TMJ in MOA group compared to the two other groups, while this pattern occurred inversely in the side with no-clicked TMJ (P < 0.009). The variation of energy was significantly less in MOA group compared to the two other groups in the no-clicked TMJ (P < 0.003). However, the proportion of the first or second part of signal energy to all energy showed that TTH group had less energy in the first part and more energy in the second part in comparison to the two other groups (P < 0.05). The study showed different changes in the energy distribution of masseter muscle activity during cycles in MOA and TTH. MOA, in contrast to TTH, had lateralization effect on EMG and interacted with TMJ click.

  9. The power features of Masseter muscle activity in tension-type and migraine without aura headache during open-close clench cycles

    PubMed Central

    Alizadeh Savareh, Behrouz; Ghanjal, Ali; Bashiri, Azadeh; Motaqi, Monireh

    2017-01-01

    Introduction Different types of headaches and TMJ click influence the masseter muscle activity. The aim of this study was to assess the trend of energy level of the electromyography (EMG) activity of the masseter muscle during open-close clench cycles in migraine without aura (MOA) and tension-type headache (TTH) with or without TMJ click. Methods Twenty-five women with MOA and twenty four women with TTH participated in the study. They matched with 25 healthy subjects, in terms of class of occlusion and prevalence of temporomandibular joint (TMJ) with click. The EMG of both masseter muscles were recorded during open-close clench cycles at a rate of 80 cycles per minute for 15 seconds. The mouth opening was restricted to two centimeters by mandibular motion frame. Signal processing steps have been done on the EMG as: noise removing, smoothing, feature extraction, and statistical analyzing. The six statistical parameters of energy computed were mean, Variance, Skewness, Kurtosis, and first and second half energy over all signal energy. Results A three-way ANOVA indicated that during all the cycles, the mean of energy was more and there was a delay in showing the peak of energy in the masseter of the left side with clicked TMJ in MOA group compared to the two other groups, while this pattern occurred inversely in the side with no-clicked TMJ (P < 0.009). The variation of energy was significantly less in MOA group compared to the two other groups in the no-clicked TMJ (P < 0.003). However, the proportion of the first or second part of signal energy to all energy showed that TTH group had less energy in the first part and more energy in the second part in comparison to the two other groups (P < 0.05). Conclusion The study showed different changes in the energy distribution of masseter muscle activity during cycles in MOA and TTH. MOA, in contrast to TTH, had lateralization effect on EMG and interacted with TMJ click. PMID:28775915

  10. Compression-induced hyperaemia in the rabbit masseter muscle: a model to investigate vascular mechano-sensitivity of skeletal muscle.

    PubMed

    Turturici, Marco; Roatta, Silvestro

    2013-03-01

    Recent evidence suggests that the mechano-sensitivity of the vascular network may underlie rapid dilatory events in skeletal muscles. Previous investigations have been mostly based either on in vitro or on whole-limb studies, neither preparation allowing one to assess the musculo-vascular specificity under physiological conditions. The aim of this work is to characterize the mechano-sensitivity of an exclusively-muscular vascular bed in vivo. In five anesthetized rabbits, muscle blood flow was continuously monitored in the masseteric artery, bilaterally (n = 10). Hyperaemic responses were evoked by compressive stimuli of different extent (50, 100 and 200 mm Hg) and duration (0.5, 1, 2 and 5 s) exerted by a servo-controlled motor on the masseter muscle. Peak amplitude of the hyperaemic response ranged from 340 ± 30% of baseline (at 50 mm Hg) to 459 ± 57% (at 200 mm Hg) (P < 0.05), did not depend on stimulus duration and exhibited very good reliability (ICC = 0.98) when reassessed at 30 min intervals. The time course of the response depended neither on applied pressure nor on the duration of the stimulus. In conclusion, for its high sensitivity and reliability this technique is adequate to characterize mechano-vascular reactivity and may prove useful in the investigation of the underlying mechanisms, with implications in the control of vascular tone and blood pressure in health and disease.

  11. Density-dependent growth and metamorphosis in the larval bronze frog Rana temporalis is influenced by genetic relatedness of the cohort.

    PubMed

    Girish, S; Saidapur, S K

    2003-06-01

    Effects of density and kinship on growth and metamorphosis in tadpoles of Rana temporalis were studied in a 2 4 factorial experiment. Fifteen egg masses were collected from streams in the Western Ghat region of south India. The tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz. 15, 30, 60 and 120/5 l water. With an increase in density level from 15 to 120 tadpoles/5 l water, duration of the larval stage increased and fewer individuals metamorphosed irrespective of whether they belonged to sibling or non-sibling groups by day 100 when the experiments were terminated. The size of individuals at metamorphosis declined significantly with increase in the density of rearing. However, at higher densities (60 and 120 tadpoles/5 l water) sibling group tadpoles performed better compared to mixed groups and took significantly less time to metamorphose. Also, more individuals of sibling groups metamorphosed compared to non-sibling groups at a given density. Mixed rearing retarded growth rates, prolonged larval duration resulting in a wider spectrum of size classes, and lowered the number of individuals recruited to terrestrial life. The study shows that interference competition occurred more strongly in cohorts of mixed relatedness than in sibling groups.

  12. The prognosis of myofascial pain syndrome (MPS) during a fixed orthodontic treatment.

    PubMed

    Tecco, Simona; Marzo, Giuseppe; Crincoli, Vito; Di Bisceglie, Beatrice; Tetè, Stefano; Festa, Felice

    2012-01-01

    Among treatments in the literature for myofascial pain syndrome (MPS), the most reliable therapies in dentistry are spray and stretch, and, although less frequently used, anesthetic injection. Adult MPS subjects are often treated using fixed orthodontic therapy for resolution of malocclusion. There is no clarity in the literature on the prognosis of MPS during orthodontic therapy. The purpose of this study was to analyze the prognosis of MPS during orthodontic treatment of subjects with malocclusion, initially diagnosed as having MPS. The analysis covered the medical records of 91 young adult Caucasians scheduled for orthodontic treatment for various malocclusions. Thirty-seven of the patients were initially diagnosed as also having MPS (T0). Thirty patients began the orthodontic treatment and were recalled for a re-evaluation of MPS after dental alignment and dental class correction was achieved (T1). A wait-and-see strategy was applied in seven subjects who were included as the control subjects. They received no treatment for MPS. At T1, a statistically significant decrease was observed in the study group in the presence of any clicking or creaking noises from the jaw joint, a significant jaw joint and jaw muscle pain reduction, and a quality of life improvement. Among patients who were depressed at the beginning of treatment, the majority felt better at the follow-up evaluation. On muscular palpation, a statistically significant decrease was found on the visual analogic scale value of the middle fibers of the temporalis muscle, temporalis tendon, clavicular and sternal division of the sternocleidomastoid muscle, masseter muscles, and posterior cervical muscles. The temporalis and the masseter muscles showed a significant decrease in the number of subjects with trigger points (TrPs) in all areas in the study group, after treatment. The digastric and sternocleidomastoid muscles also showed a significant reduction in the number of subjects with TrPs. Subjects with

  13. 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.

  14. GABAB receptors in the NTS mediate the inhibitory effect of trigeminal nociceptive inputs on parasympathetic reflex vasodilation in the rat masseter muscle.

    PubMed

    Ishii, Hisayoshi; Izumi, Hiroshi

    2012-03-15

    The present study was designed to examine whether trigeminal nociceptive inputs are involved in the modulation of parasympathetic reflex vasodilation in the jaw muscles. This was accomplished by investigating the effects of noxious stimulation to the orofacial area with capsaicin, and by microinjecting GABA(A) and GABA(B) receptor agonists or antagonists into the nucleus of the solitary tract (NTS), on masseter hemodynamics in urethane-anesthetized rats. Electrical stimulation of the central cut end of the cervical vagus nerve (cVN) in sympathectomized animals bilaterally increased blood flow in the masseter muscle (MBF). Increases in MBF evoked by cVN stimulation were markedly reduced following injection of capsaicin into the anterior tongue in the distribution of the lingual nerve or lower lip, but not when injected into the skin of the dorsum of the foot. Intravenous administration of either phentolamine or propranolol had no effect on the inhibitory effects of capsaicin injection on the increases of MBF evoked by cVN stimulation, which were largely abolished by microinjecting the GABA(B) receptor agonist baclofen into the NTS. Microinjection of the GABA(B) receptor antagonist CGP-35348 into the NTS markedly attenuated the capsaicin-induced inhibition of MBF increase evoked by cVN stimulation, while microinjection of the GABA(A) receptor antagonist bicuculline did not. Our results indicate that trigeminal nociceptive inputs inhibit vagal-parasympathetic reflex vasodilation in the masseter muscle and suggest that the activation of GABA(B) rather than GABA(A) receptors underlies the observed inhibition in the NTS.

  15. 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. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

  16. Illusion caused by vibration of muscle spindles reveals an involvement of muscle spindle inputs in regulating isometric contraction of masseter muscles.

    PubMed

    Tsukiboshi, Taisuke; Sato, Hajime; Tanaka, Yuto; Saito, Mitsuru; Toyoda, Hiroki; Morimoto, Toshifumi; Türker, Kemal Sitki; Maeda, Yoshinobu; Kang, Youngnam

    2012-11-01

    Spindle Ia afferents may be differentially involved in voluntary isometric contraction, depending on the pattern of synaptic connections in spindle reflex pathways. We investigated how isometric contraction of masseter muscles is regulated through the activity of their muscle spindles that contain the largest number of intrafusal fibers among skeletal muscle spindles by examining the effects of vibration of muscle spindles on the voluntary isometric contraction. Subjects were instructed to hold the jaw at resting position by counteracting ramp loads applied on lower molar teeth. In response to the increasing-ramp load, the root mean square (RMS) of masseter EMG activity almost linearly increased under no vibration, while displaying a steep linear increase followed by a slower increase under vibration. The regression line of the relationship between the load and RMS was significantly steeper under vibration than under no vibration, suggesting that the subjects overestimated the ramp load and excessively counteracted it as reflected in the emergence of bite pressure. In response to the decreasing-ramp load applied following the increasing one, the RMS hardly decreased under vibration unlike under no vibration, leading to a generation of bite pressure even after the offset of the negative-ramp load until the vibration was ceased. Thus the subjects overestimated the increasing rate of the load while underestimating the decreasing rate of the load, due to the vibration-induced illusion of jaw opening. These observations suggest that spindle Ia/II inputs play crucial roles both in estimating the load and in controlling the isometric contraction of masseter muscles in the jaw-closed position.

  17. Regulation of jaw-specific isoforms of myosin-binding protein-C and tropomyosin in regenerating cat temporalis muscle innervated by limb fast and slow motor nerves.

    PubMed

    Kang, Lucia H D; Hoh, Joseph F Y

    2010-11-01

    Cat jaw-closing muscles are a distinct muscle allotype characterized by the expression of masticatory-specific myofibrillar proteins. Transplantation studies showed that expression of masticatory myosin heavy chain (m-MyHC) is promoted by fast motor nerves, but suppressed by slow motor nerves. We investigated whether masticatory myosin-binding protein-C (m-MBP-C) and masticatory tropomyosin (m-Tm) are similarly regulated. Temporalis muscle strips were transplanted into limb muscle beds to allow innervation by fast or slow muscle nerve during regeneration. Regenerated muscles were examined postoperatively up to 168 days by peroxidase IHC using monoclonal antibodies to m-MyHC, m-MBP-C, and m-Tm. Regenerates in both muscle beds expressed fetal and slow MyHCs, m-MyHC, m-MBP-C, and m-Tm during the first 4 weeks. Longer-term regenerates innervated by fast nerve suppressed fetal and slow MyHCs, retaining m-MyHC, m-MBP-C, and m-Tm, whereas fibers innervated by slow nerve suppressed fetal MyHCs and the three masticatory-specific proteins, induced slow MyHC, and showed immunohistochemical characteristics of jaw-slow fibers. We concluded that expression of m-MBP-C and m-Tm is coregulated by m-MyHC and that neural impulses to limb slow muscle are capable of suppressing masticatory-specific proteins and to channel gene expression along the jaw-slow phenotype unique to jaw-closing muscle.

  18. 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

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

    PubMed

    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.

  20. Neuromuscular interfacing: a novel approach to EMG-driven multiple DOF physiological models.

    PubMed

    Pau, James W L; Xie, Shane S Q; Xu, W L

    2013-01-01

    This paper presents a novel approach that involves first identifying and verifying the available superficial muscles that can be recorded by surface electromyography (EMG) signals, and then developing a musculoskeletal model based on these findings, which have specifically independent DOFs for movement. Such independently controlled multiple DOF EMG-driven models have not been previously developed and a two DOF model for the masticatory system was achieved by implementing independent antagonist muscle combinations for vertical and lateral movements of the jaw. The model has six channels of EMG signals from the bilateral temporalis, masseter and digastric muscles to predict the motion of the mandible. This can be used in a neuromuscular interface to manipulate a jaw exoskeleton for rehabilitation. For a range of different complexities of jaw movements, the presented model is able to consistently identify movements with 0.28 - 0.46 average normalized RMSE. The results demonstrate the feasibility of the approach at determining complex multiple DOF movements and its applicability to any joint system.

  1. [Electromyographic changes in bruxism after auricular stimulation. A randomized controlled clinical trial].

    PubMed

    Romoli, M; Ridi, R; Giommi, A

    2003-08-01

    The aim of this study was to verify in bruxism patients the possible efficacy of auricular stimulation in reducing the hypertonicity of some masticatory muscles. Forty-three bruxism patients were randomly allocated to 3 groups: acupuncture, needle contact for 10 seconds, no treatment (control). Helkimo's clinical dysfunction index (CDI) and anamnestic dysfunction index (ADI) were used to assess the functional state of the masticatory system. The resting electrical activity of the anterior temporalis (AT), masseter (MM), digastric (DA) and sternocleidomastoid (SCM) muscles was measured, according to Jankelson, with surface electrodes at baseline, after stimulation and continually for 30 minutes (120 measurements in total). The electromyographical variations in the 3 groups were studied with t test for independent samples. Acupuncture and needle contact were superior to control in reducing the muscle hypertonicity of all muscles except SCM. In the comparison between acupuncture and needle contact the former showed better results only for the right TA and left DA (p = 0.000). In this study it was possible to measure the efficacy of the stimulation of only one point or area, which is an ideal model for research in acupuncture. The auricular area we chose for stimulation was never used before for the purpose of relaxing masticatory muscles. Acupuncture and needle contact for 10 seconds showed similar effects.

  2. 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.

  3. Activation of peripheral delta–opioid receptors leads to anti-hyperalgesic responses in the masseter muscle of male and female rats

    PubMed Central

    Saloman, Jami L.; Niu, Katelyn Y.; Ro, Jin Y.

    2011-01-01

    In this project, we examined peripheral δ-opioid receptor (DOR)-mediated anti-hyperalgesic responses in the context of an acute orofacial muscle pain condition in both male and female rats. We also investigated whether the ATP-sensitive K+ channel (KATP), a downstream target of OR signaling, contributes to DOR-mediated anti-hyperalgesic responses. Local pretreatment of the masseter with a DOR agonist, DPDPE, dose-dependently attenuated capsaicin-induced mechanical hypersensitivity in both male and female rats. However, there were sex differences in the potency of local DPDPE in that a 10 fold higher dose of DPDPE was required in female rats to produce the level of anti-hyperalgesia achieved in male rats. The sex differences in the DPDPE effect may not be fully explained by DOR expression level since there was no significant sex difference in DOR mRNA levels in trigeminal ganglia (TG). Finally, pretreatment of the masseter with the KATP antagonist, glibenclamide significantly blocked the effects of DPDPE in male rats suggesting that the peripheral DOR effect is mediated by the KATP. These studies revealed novel information about sex differences with regards to peripherally localized DOR-mediated anti-hyperalgesia under an orofacial muscle pain condition. PMID:21664434

  4. Effects of gadolinium chloride on basal flow and compression-induced rapid hyperemia in the rabbit masseter muscle.

    PubMed

    Turturici, M; Roatta, S

    2014-06-01

    Aim of the present study is to investigate the role of mechano-sensitive channels on basal muscle blood flow and on the compression-induced rapid hyperaemia. To this aim, the mechano-sensitive channel blocker Gadolinium (Gd(3+)) is employed, which already proved to reduce the myogenic response in isolated vessels. Muscle blood flow (MaBF) was recorded from the masseteric artery in 8 urethane-anesthetized rabbits. Rapid hyperemic responses were evoked by 1-s lasting compressions of the masseter muscle (MC) delivered before and after close arterial infusion of Gd(3+) in the masseteric artery. Three infusions were performed at 1-h interval, producing estimated plasma concentration (EPC) of 0.045, 0.45 and 4.5 mM, in the masseteric artery. The amplitude of the hyperaemic response to MC, equal to 195±77% of basal flow in control condition, was reduced by 9.5±19.4% (p=0.18) and 45±28% (p<0.01) while basal MaBf increased by 10±3% (p=0.90) and by 68±30% (p<0.01) at EPC of 0.045 and 0.45 mM, respectively. At EPC of 4.5 mM a strong reduction in both MaBF (by 54±13%, p<0.01) and MC response (75±12%, p<0.01) was instead observed. These effects did not depend on time from infusion. At all doses employed Gd(3+) never affected arterial blood pressure, heart rate and contralateral MaBF. While the effects observed at the highest EPC likely result from blood vessel occlusion due to Gd(3+) precipitation, the effects observed at lower concentrations demonstrate that Gd(3+) affects musculo-vascular function by decreasing both resting vascular tone and responsiveness to mechanical stimuli. The results are compatible with a Gd(3+)-induced blockade of vascular mechano-sensitive channels.

  5. 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.

  6. 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

  7. Comparing the Electromyographic Features of the Masseter and Temporal Muscles in Patients with full Mouth Implant-supported FDPs and Natural Dentition.

    PubMed

    Seifi, Mahdieh; Nodehi, Davood; Ghahramanloo, Ahmad; Ahmadi, Zahra; Farhangnia, Azade; Saedi, Morteza; Mozaffari, Hamid Reza; Sharifi, Roohollah

    2017-03-01

    Due to increasing demands for a full mouth implant reconstructions and the fact that the most failures are associated with biomechanical complications, determining the effect of different occlusal patterns on these complications seems inevitable. The aim of this study is to compare affection of different occlusal designs in full mouth implant reconstructed patients on electromyographic activity of temporal and masseter muscles compared to natural dentition. Thirty-two patients were included in this study, considering that 16 patients had natural dentition and the other 16 were full mouth implant reconstruction patients. In both groups, the participants were divided into two subgroups: 8 patients had canine guidance occlusal pattern and the other eight had a group function occlusal pattern. Muscle contractions were studied during both maximum intercuspation and lateral excursions to the point of intercanine contact using an electromyography device. The average percentages of masseter muscle contraction in lateral excursions relative to maximum intercuspation were as follows: 72.20% in full mouth implant reconstruction patients with group function occlusion 69.49% in natural dentition with group function occlusion 58.85% in full mouth implant reconstruction patients with canine guidance occlusion 30.91% in natural dentition with canine guidance occlusion. The average percentages of temporal muscle contraction in lateral excursions relative to maximum intercuspation were as follows: 70.87% in full mouth implant reconstruction patients with group function occlusion 78.57% in natural dentition with group function occlusion 51.99% in full mouth implant reconstruction patients with canine guidance occlusion 31.55% in natural dentition with canine guidance occlusion. A canine guidance occlusal pattern in both, natural dentition and full mouth implant-supported FDP, patients resulted in decreased muscle contraction. This decreasing is more significant in natural dentition

  8. Evidence that the contraction-induced rapid hyperemia in rabbit masseter muscle is based on a mechanosensitive mechanism, not shared by cutaneous vascular beds.

    PubMed

    Turturici, Marco; Mohammed, Mazher; Roatta, Silvestro

    2012-08-15

    Several mechanisms have been hypothesized to contribute to the rapid hyperemia at the onset of exercise. The aim of the present study was to investigate the role played by the mechanosensitivity of the vascular network. In 12 anesthetized rabbits blood flow was recorded from the exclusively muscular masseteric artery in response to brief spontaneous contractions (BSC) of the masseter muscle, artery occlusion (AO), muscle compression (MC), and muscle stretch (MS). Activation of masseter muscle was monitored by electromyography (EMG). Responses to AO were also recorded from the mostly cutaneous facial and the central ear arteries. Five animals were also tested in the awake condition. The hyperemic response to BSC (peak amplitude of 394 ± 82%; time to peak of 1.8 ± 0.8 s) developed with a latency of 300-400 ms from the beginning of the EMG burst and 200-300 ms from the contraction-induced transient flow reduction. This response was neither different from the response to AO (peak amplitude = 426 ± 158%), MC, and MS (P = 0.23), nor from the BSC response in the awake condition. Compared with the masseteric artery, the response to AO was markedly smaller both in the facial (83 ± 18%,) and in the central ear artery (68 ± 20%) (P < 0.01). In conclusion, the rapid contraction-induced hyperemia can be replicated by a variety of stimuli affecting transmural pressure in muscle blood vessels and is thus compatible with the Bayliss effect. This prominent mechanosensitivity appears to be a characteristic of muscle and not cutaneous vascular beds.

  9. Comparing the Electromyographic Features of the Masseter and Temporal Muscles in Patients with full Mouth Implant-supported FDPs and Natural Dentition

    PubMed Central

    Seifi, Mahdieh; Nodehi, Davood; Ghahramanloo, Ahmad; Ahmadi, Zahra; Farhangnia, Azade; Saedi, Morteza; Mozaffari, Hamid Reza; Sharifi, Roohollah

    2017-01-01

    Background: Due to increasing demands for a full mouth implant reconstructions and the fact that the most failures are associated with biomechanical complications, determining the effect of different occlusal patterns on these complications seems inevitable. The aim of this study is to compare affection of different occlusal designs in full mouth implant reconstructed patients on electromyographic activity of temporal and masseter muscles compared to natural dentition. Methods: Thirty-two patients were included in this study, considering that 16 patients had natural dentition and the other 16 were full mouth implant reconstruction patients. In both groups, the participants were divided into two subgroups: 8 patients had canine guidance occlusal pattern and the other eight had a group function occlusal pattern. Muscle contractions were studied during both maximum intercuspation and lateral excursions to the point of intercanine contact using an electromyography device. Results: The average percentages of masseter muscle contraction in lateral excursions relative to maximum intercuspation were as follows: 72.20% in full mouth implant reconstruction patients with group function occlusion 69.49% in natural dentition with group function occlusion 58.85% in full mouth implant reconstruction patients with canine guidance occlusion 30.91% in natural dentition with canine guidance occlusion. The average percentages of temporal muscle contraction in lateral excursions relative to maximum intercuspation were as follows: 70.87% in full mouth implant reconstruction patients with group function occlusion 78.57% in natural dentition with group function occlusion 51.99% in full mouth implant reconstruction patients with canine guidance occlusion 31.55% in natural dentition with canine guidance occlusion. Conclusion: A canine guidance occlusal pattern in both, natural dentition and full mouth implant-supported FDP, patients resulted in decreased muscle contraction. This decreasing

  10. Aging affects different human muscles in various ways. An image analysis of the histomorphometric characteristics of fiber types in human masseter and vastus lateralis muscles from young adults and the very old.

    PubMed

    Kirkeby, S; Garbarsch, C

    2000-01-01

    This study is an attempt to objectively evaluate age-related changes in human muscles by use of histomorphometric methods. Aging in humans induces dramatic transformations in the skeletal muscles but little is known as to whether or not the aging processes per se may affect all muscles equally. In this study aging of two human muscles with different functions, origin and nerve supply is compared. Sections were cut from masseter and vastus lateralis muscles obtained from young adults aged 18-24 years and from the very old aged 90-102 years. Muscle fiber types were classified with the traditional myofibrillar ATPase staining. Various histomorphometric parameters of the different fiber types in human masseter and vastus lateralis muscle sections were obtained by image analyses to evaluate the age-related changes in the muscle fibers. The following variables were calculated: the number of each fiber type per photographed area; the area of each fiber and two indicators for the shape of the muscle fibers. In the aging muscles there was no relative preferential loss of a fiber type. High numbers of intermediate ATPase-stained fibers (IM fibers) were found in some old vastus muscles but were only sporadic in young vastus muscles. However, there was no change in the percentage distribution of intermediate ATPase-stained fibers when young and very old human masseter muscles were compared. Incubation of the sections with antimyosin antibodies showed that the IM fibers in old masseter and old vastus contained different myosin heavy chains. Thus ATPase activity and anti-myosin staining displayed a somewhat different pattern of fiber type distribution. The main changes in the shape and area indicated that type I fibers in the masseter became more circular while in the vastus they decreased significantly in size. The type II fibers in the vastus became very small and deviated significantly from circularity whereas the type II fibers in the masseter only exhibited a decrease in

  11. Effect of intravenous infusion of a beta-adrenergic blocking agent on the haemodynamic changes in human masseter muscle induced by cold-pressor stimulation.

    PubMed

    Maekawa, K; Kuboki, T; Miyawaki, T; Shimada, M; Yamashita, A; Clark, G T

    1999-06-01

    Eight healthy non-smoking males (mean age: 24.1 +/- 1.1 years) without any history of chronic muscle pain and migraine participated in this study. Haemoglobin (Hb) and oxygen (O2) saturation in the right masseter muscle were continuously recorded with a non-invasive near-infrared spectroscopic device. Heart rate and blood pressure were also recorded. The experiment had three phases: a placebo drug (physiological saline) with cold-pressor trial, a 30-sec maximal voluntary clenching (MVC) trial, and a propranolol with cold-pressor trial. The saline and drug trials each involved continuous recording for 1 min before, 2 min during and 5 min after the cold-pressor stimulation (4 degrees C). Physiological saline (20 ml) or propranolol hydrochloride (20 ml) were infused at the rate of 2 ml/min. This infusion was begun 20 min before the baseline recording and participants did not know which solution (saline or propranolol) was being infused. For the MVC trial, each participant was asked to perform a 30-sec clench of their jaw-closing muscles. There was a rest period of 15 min between each trial. The individual Hb and O2 data were normalized so that the baseline at the beginning of the experiment was equal to zero, and the Hb and O2 data were normalized as a percentage of the individual's own highest absolute Hb and O2 after and during the MVC, respectively. The results showed that the mean baseline Hb 1 min before cold-pressor stimulation was significantly lower in the beta-blocker trial than in the placebo trial (p = 0.035). The mean change in Hb from baseline during cold-pressor stimulation in the beta-blocker trial was also significantly less than in the placebo trial (p = 0.035). The mean Hb rebound change after the cold-pressor stimulation in the beta-blocker trial was significantly higher than in the placebo trial, and no significant heart-rate differences were observed in the period after cold-pressor stimulation. Overall, the mean heart rate before and during that

  12. Long lasting pain hypersensitivity following ligation of the tendon of the masseter muscle in rats: A model of myogenic orofacial pain

    PubMed Central

    2010-01-01

    Background A major subgroup of patients with temporomandibular joint (TMJ) disorders have masticatory muscle hypersensitivity. To study myofacial temporomandibular pain, a number of preclinical models have been developed to induce myogenic pain of the masseter muscle, one of the four muscles involved in mastication. The currently used models, however, generate pain that decreases over time and only lasts from hours to weeks and hence are not suitable for studying chronicity of the myogenic pain in TMJ disorders. Here we report a model of constant myogenic orofacial pain that lasts for months. Results The model involves unilateral ligation of the tendon of the anterior superficial part of the rat masseter muscle (TASM). The ligation of the TASM was achieved with two chromic gut (4.0) ligatures via an intraoral approach. Nocifensive behavior of the rat was assessed by probing the skin site above the TASM with a series of von Frey filaments. The response frequencies were determined and an EF50 value, defined as the von Frey filament force that produces a 50% response frequency, was derived and used as a measure of mechanical sensitivity. Following TASM ligation, the EF50 of the injured side was significantly reduced and maintained throughout the 8-week observation period, suggesting the presence of mechanical hyperalgesia/allodynia. In sham-operated rats, the EF50 of the injured side was transiently reduced for about a week, likely due to injury produced by the surgery. Somatotopically relevant Fos protein expression was indentified in the subnucleus caudalis of the spinal trigeminal sensory complex. In the same region, persistent upregulation of NMDA receptor NR1 phosphorylation and protein expression and increased expression of glial markers glial fibrillary acidic protein (astroglia) and CD11b (microglia) were found. Morphine (0.4-8 mg/kg, s.c.) and duloxetine (0.4-20 mg/kg, i.p.), a selective serotonin-norepinephrine reuptake inhibitor, produced dose

  13. A preliminary analysis of the relationship between jaw-muscle architecture and jaw-muscle electromyography during chewing across primates.

    PubMed

    Vinyard, Christopher J; Taylor, Andrea B

    2010-04-01

    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 two genera of strepsirrhines (Lemur and Otolemur) and five genera of anthropoids (Aotus, Callithrix, Cebus, Macaca, and 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 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.

  14. 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

  15. Evaluation of tongue-, jaw-, and swallowing-related muscle coordination during voluntarily triggered swallowing.

    PubMed

    Ono, Takahiro; Iwata, Hisayuki; Hori, Kazuhiro; Tamine, Kenichi; Kondoh, Jugo; Hamanaka, Sato; Maeda, Yoshinobu

    2009-01-01

    The prosthodontic treatment of dysphagic patients may preclude favorable treatment outcomes due to uncoordinated or discordant oral and pharyngeal functions. Since optimal treatment requires a full understanding of the mechanism of oropharyngeal swallowing, this study seeks to describe the normal temporal pattern of tongue-, jaw-, and swallowing-related muscle coordination during voluntarily triggered swallows in healthy patients. Tongue pressure against the hard palate at seven measuring points, swallowing sounds, and surface electromyography (EMG) activity of the masseter, anterior digastric, and infrahyoid muscles during voluntarily triggered swallowing were recorded in seven healthy male volunteers. The order of onset and offset of these parameters was analyzed by repeated-measures two-way analysis of variance. The onset of anterior digastric muscle activity occurred first and was significantly earlier than the onset of the masseter or infrahyoid muscles and tongue pressure. The onset of masseter muscle activity was also significantly earlier than that of the infrahyoid muscle and tongue pressure. Offset of masseter activity was almost simultaneous with the swallowing sound and was significantly earlier than the offset of the anterior digastric and infrahyoid muscles as well as tongue pressure. The EMG burst of the anterior digastric muscle continued until the offset of tongue pressure, and was followed by the offset of infrahyoid muscle activity. The temporal coordination patterns of the tongue, jaw, and oropharyngeal muscles during voluntarily triggered swallowing appear to agree with known safe management of a bolus and offer criteria for evaluating the function of oropharyngeal swallowing.

  16. Myosin proteins identified from masseter muscle using quantitative reverse transcriptase-polymerase chain reaction--a pilot study of the relevance to orthodontics.

    PubMed

    Suchak, Archna; Hunt, Nigel P; Shah, Rishma; Sinanan, Andrea C M; Lloyd, Tim; Lewis, Mark P

    2009-04-01

    There is a clearly established relationship between masticatory muscle structure and facial form. Human studies in this area, however, have been limited, especially in consideration of the myosin heavy chain (MyHC) family of contractile proteins. The aim of this pilot study was to assess if differences were detectable between genotype with respect to MyHC isoforms and the vertical facial phenotype in a sample of nine Caucasian female patients, age range 18-49 years, using a novel rapid technique. Masseter muscle biopsies were taken from patients with a range of vertical facial form. The levels of expression of the MyHC isoform genes MYH 1, 2, 3, 6, 7, and 8 were compared with the expression in a female calibrator patient aged 23 years with normal vertical facial form, using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Statistical analysis was undertaken using Pearson correlation coefficient. The results showed that there were distinct differences in gene expression between patients with a wide range of variation although changes in MYH1 were consistent with one cephalometric variable, the maxillo-mandibular angle. The full procedure, from start to finish, can be completed within half a day. Rapid genotyping of patients in this way could reveal important information of relevance to treatment. This technology has potential as a diagnostic and prognostic aid when considering correction of certain malocclusions.

  17. Effects of muscle pain induced by glutamate injections during sustained clenching on the contraction pattern of masticatory muscles.

    PubMed

    Michelotti, Ambrosina; Cioffi, Iacopo; Rongo, Roberto; Borrelli, Roberta; Chiodini, Paolo; Svensson, Peter

    2014-01-01

    To evaluate the contraction pattern of masticatory muscles during sustained clenching tasks with or without experimental pain induced by glutamate injection into the masseter muscle. It was hypothesized that acute muscle pain could induce compensatory changes in the electromyographic (EMG) activity of the masticatory muscles. Fifteen volunteers (seven males, mean age ± SD = 29.7 ± 1.1 years; eight females, mean age ± SD = 23.5 ± 1.2 years) were recruited in a crossover experimental study. All subjects participated in two randomized 20-minute experimental sessions. Each subject was asked to clench at 25% of the maximum voluntary contraction (MVC). After 10 minutes, isotonic saline or glutamate was injected in random order into the right masseter. EMG activity (root mean square [RMS] and mean power frequency [MPF]) was assessed in the masseter and anterior temporalis muscles on both sides. Pain and fatigue were assessed by 0-10 numeric rating scales (NRS) every minute. Differences between conditions (isotonic saline vs glutamate) for all the outcome parameters were analyzed by using a mixed effect model. The EMG activity of the masticatory muscles and pain and fatigue scores were not dependent on isotonic saline/glutamate injection (all P > .05). The RMS in the temporalis and masseter muscles increased with time (right masseter P = 0.001, left masseter P = .004, right temporalis P = .22, left temporalis P = .006), whereas the MPF decreased (right masseter P = .0001, left masseter P < .0001, right temporalis P = .51, left temporalis P = .0005). Scores for fatigue and pain increased during the experimental sessions (all P < .05). Intramuscular injection of glutamate caused more pain than isotonic saline but did not affect the contraction pattern of the masticatory muscles during a sustained clenching task. This finding strongly suggests the adaptive capacity of the stomatognathic system in the presence of acute nociceptive inputs.

  18. Immediate effects of hamstring stretching alone or combined with ischemic compression of the masseter muscle on hamstrings extensibility, active mouth opening and pain in athletes with temporomandibular dysfunction.

    PubMed

    Espejo-Antúnez, Luis; Castro-Valenzuela, Elisa; Ribeiro, Fernando; Albornoz-Cabello, Manuel; Silva, Anabela; Rodríguez-Mansilla, Juan

    2016-07-01

    To assess the immediate effects of hamstrings stretching alone or combined with ischemic compression of the masseter muscle on hamstrings extensibility, active mouth opening and pain in athletes with temporomandibular dysfunction and hamstrings shortening. Forty-two participants were randomized to receive the stretching technique (n = 21) or the stretching plus the ischemic compression (n = 21). Outcome measures were: hamstrings extensibility, active mouth opening, pressure pain thresholds and pain intensity. Both interventions improved significantly active mouth opening (group 1: 35.7 ± 6.7 to 39.1 ± 7.6 mm, p < 0.001; group 2: 34.0 ± 6.2 to 37.6 ± 5.6 mm, p < 0.001), active knee extension (group 1: 33.1 ± 8.5 to 40.8 ± 8.2°, p < 0.001; group 2: 28.9 ± 6.5 to 35.5 ± 6.4°, p < 0.001) and pain. No significant differences were found between interventions. Hamstrings stretching induced an acute improvement in hamstrings extensibility, active mouth opening and pain. Moreover, the addition of ischemic compression did not induce further improvements on the assessed parameters. Copyright © 2016. Published by Elsevier Ltd.

  19. [Study of peroxisome proliferator-activated receptor-γ coactivator-1α expression and cytoapoptosis in masseter muscles of unilateral chewing rat].

    PubMed

    Yang, Yingying; Ding, Tingting; Wu, Qingting; Kong, Jingjing; Qi, Dong; Ji, Ping

    2014-07-01

    To investigate the changes of peroxisome proliferator- activated receptor-γ coactivator -1α (PGC-1α) mRNA and cytoapoptosis in the rats' masseter muscle which had been influenced by unilateral chewing, and to explore the theoretical foundation of changes in masticatory muscles induced by unilateral chewing. The animal models were established by extracting the Wistar rats' left maxillary molars. Thirty- six female Wistar rats were randomly divided into four groups of 2, 4, 6 and 8 weeks, nine each. In each group there were six rats with molar extracted and three as control. The Ca²⁺ level was detected by atomic spectrophotometric method. The relative expression of PGC-1α mRNA was detected by real- time fluorescent quantitative PCR. The apoptosis index was detected by Hoechst staining. The Ca²⁺ level in the muscle on the extraction side were significantly higher than that in the controls in the beginning stage of unilateral chewing, and reached the peak at the 4th week [(43.62 ± 2.36) µg/g]. The relative expressions of PGC-1α increased from the beginning and reached the maximum level at the 4th week [extraction side: (1.57 ± 0.10); non-extraction side: (1.92 ± 0.06)], while the relative expressions of PGC-1α in 6 and 8 weeks decreased gradually [extraction side: (1.06 ± 0.08), (1.08 ± 0.07); non- extraction side: (1.09 ± 0.10), (1.11 ± 0.08)]. The changes of apoptosis index on non- extraction side increased continually and peaked at the 6th week [(38.56 ± 1.64)%]. PGC-1α and cytoapoptosis played important roles in different stages of tissue remodeling induced by unilateral chewing.

  20. The contribution of Islet1-expressing splanchnic mesoderm cells to distinct branchiomeric muscles reveals significant heterogeneity in head muscle development.

    PubMed

    Nathan, Elisha; Monovich, Amir; Tirosh-Finkel, Libbat; Harrelson, Zachary; Rousso, Tal; Rinon, Ariel; Harel, Itamar; Evans, Sylvia M; Tzahor, Eldad

    2008-02-01

    During embryogenesis, paraxial mesoderm cells contribute skeletal muscle progenitors, whereas cardiac progenitors originate in the lateral splanchnic mesoderm (SpM). Here we focus on a subset of the SpM that contributes to the anterior or secondary heart field (AHF/SHF), and lies adjacent to the cranial paraxial mesoderm (CPM), the precursors for the head musculature. Molecular analyses in chick embryos delineated the boundaries between the CPM, undifferentiated SpM progenitors of the AHF/SHF, and differentiating cardiac cells. We then revealed the regionalization of branchial arch mesoderm: CPM cells contribute to the proximal region of the myogenic core, which gives rise to the mandibular adductor muscle. SpM cells contribute to the myogenic cells in the distal region of the branchial arch that later form the intermandibular muscle. Gene expression analyses of these branchiomeric muscles in chick uncovered a distinct molecular signature for both CPM- and SpM-derived muscles. Islet1 (Isl1) is expressed in the SpM/AHF and branchial arch in both chick and mouse embryos. Lineage studies using Isl1-Cre mice revealed the significant contribution of Isl1(+) cells to ventral/distal branchiomeric (stylohyoid, mylohyoid and digastric) and laryngeal muscles. By contrast, the Isl1 lineage contributes to mastication muscles (masseter, pterygoid and temporalis) to a lesser extent, with virtually no contribution to intrinsic and extrinsic tongue muscles or extraocular muscles. In addition, in vivo activation of the Wnt/beta-catenin pathway in chick embryos resulted in marked inhibition of Isl1, whereas inhibition of this pathway increased Isl1 expression. Our findings demonstrate, for the first time, the contribution of Isl1(+) SpM cells to a subset of branchiomeric skeletal muscles.

  1. Development of Chewing in Children From 12 to 48 Months: Longitudinal Study of EMG Patterns

    PubMed Central

    GREEN, JORDAN R.; MOORE, CHRISTOPHER A.; RUARK, JACKI L.; RODDA, PAULA R.; MORVÉE, WENDY T.; VanWITZENBURG, MARCUS J.

    2014-01-01

    Developmental changes in the coordinative organization of masticatory muscles were examined longitudinally in four children over 49 experimental sessions spanning the age range of 12–48 mo. Electromyographic (EMG) records were obtained for right and left masseter muscles, right and left temporalis muscles, and the anterior belly of the digastric. Two independent analytic processes were employed, one that relied on identification of onset and offset of muscle activation and a second that used pairwise cross-correlational techniques. The results of these two analyses, which were found to be consistent with each other, demonstrated that the basic chewing pattern of reciprocally activated antagonistic muscle groups is established by 12 mo of age. Nevertheless, chewing efficiency appears to be improved through a variety of changes in the chewing pattern throughout early development. Coupling of activity among the jaw elevator muscles was shown to strengthen with maturation, and the synchrony of onset and offset of these muscles also increased. Coactivation of antagonistic muscles decreased significantly with development. This decrease in antagonistic coactivation and increase in synchrony among jaw elevators, and a parallel decrease in EMG burst duration, were taken as evidence of increased chewing efficiency. No significant differences in the frequency of chewing were found across the ages studied. Additional considerations include the appropriateness of this coordinative infrastructure for other developing oromotor skills, such as speech production. It is suggested that the relatively fixed coordinative framework for chewing exhibited by these children would not be suitable for adaptation to speech movements, which have been shown to rely on a much more variable and adjustable coordinative organization. PMID:9163386

  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. Optimization of jaw muscle activity and fine motor control during repeated biting tasks.

    PubMed

    Kumar, Abhishek; Svensson, Krister G; Baad-Hansen, Lene; Trulsson, Mats; Isidor, Flemming; Svensson, Peter

    2014-12-01

    To investigate if repeated holding and splitting of food morsel change the variability of force and jaw muscle activity in participants with natural dentition. Twenty healthy volunteers (mean age=26.2±3.9 years) participated in a single session divided into six series. Each series consisted of ten trials of a standardized behavioural task (total 60 trials) involving holding and splitting a flat-faced tablet (8mm, 180mg) placed on a bite force transducer with the anterior teeth. The hold and split forces along with the electromyographic (EMG) activity of the left and right masseter (MAL and MAR), left anterior temporalis (TAL) and digastric (DIG) muscles were recorded. A series (ten trials) of natural biting tasks was also performed before and after the six series of the behavioural task. The mean hold force (P<0.001) but not the mean split force (P=0.590) showed significant effect of number of series. No significant effect of series was seen on the variability of hold and split force and the EMG activity except for the variability of EMG activity for MAL during the hold phase (P=0.021) and DIG during the split phase (P<0.001). The behavioural task had no effect on the EMG activity of the natural biting task. There was no evident optimization of jaw motor function in terms of reduction in the variability of bite force values and muscle activity, when this simple task was repeated up to sixty times in participants with normal intact periodontium. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Comparison between sensory and motor transcutaneous electrical nervous stimulation on electromyographic and kinesiographic activity of patients with temporomandibular disorder: a controlled clinical trial

    PubMed Central

    2013-01-01

    Background The purpose of the present controlled clinical trial was to assess the effect of a single 60 min application of transcutaneous electrical nervous stimulation (TENS) at sensory stimulation threshold (STS), compared to the application of motor stimulation threshold (MTS) as well as to untreatment, on the surface electromyographic (sEMG) and kinesiographic activity of patients with tempormanbibular disorder (TMD). Methods Sixty female subjects, selected according to the inclusion/exclusion criteria, suffering from unilateral TMD in remission were assigned to MTS, STS or untreatment. Pre- and post-treatment differences in the sEMG activity of temporalis anterior (TA), masseter (MM), digastric (DA) and sternocleidomastoid muscles (SCM), as well in the interocclusal distance (ID), within group were tested using the Wilcoxon test, while differences among groups were assessed by Kruskal-Wallis test; the level of significance was set at p ≤ 0.05. Results Significant pre- and post-treatment differences were observed in MTS and STS groups, for TA and MM of both sides; no significant difference was detected between MTS and STS groups. Kinesiographic results showed that the vertical component of ID was significantly increased after TENS in MTS and STS groups. Conclusions STS TENS could be effective, as well as MTS, in reduce the sEMG activity of masticatory muscles and to improve the ID of TMD patients in remission. Future studies are needed to confirm the results of the present study. Clinical relevance. The present study demonstrates that the application of TENS is effective in reduce the sEMG activity, as well as in increasing the ID of patients with TMD; our study did not support superior effectiveness of MTS or STS. Trial registration ClinicalTrials.gov: NCT01832207 PMID:23672400

  5. Effect of glucocorticoïd receptor ligands on myosin heavy chains expression in rat skeletal muscles during controllable stress.

    PubMed

    Martrette, J M; Hartmann, N; Westphal, A; Favot, L

    2004-01-01

    The influence of agonist (dexamethasone) and antagonist (mifepristone) of glucocorticoïd receptor during controllable painless stress was evaluated on myosin heavy chains expression in three masticatory and two nape rat muscles: anterior digastric (AD), anterior temporalis (AT), masseter superficialis (MS), longissimus capitis (L) and rectus capitis dorsalis major (R). The relative amounts of myosin heavy chain (MHC) protein isoform contained were significantly affected in four muscles studied by dexamethasone and in three muscles studied under mifepristone, versus control during the stress procedure, after only 1 week of treatment. The control group AT muscles contained respectively 18.2% of MHC 2A, 34.5% of MHC 2X and 47.4% of MHC 2B. The effects of dexamethasone and mifepristone were opposite in this muscle: under dexamethasone, the relative proportions of the three isoforms were 14.2, 31.0 and 54.8%: consequently, MHC 2A and 2X decreased with the profit of 2B. Under mifepristone, the relative proportions were 21.1, 36.6 and 42.3% (MHC 2A and 2X increased to the detriment of 2B). The L muscle was not affected by the two treatments and MS muscle was only affected by dexamethasone. Dexamethasone increased MHC 2B to the detriment of MHC 2A in MS, AD and R. Mifepristone and dexamethasone induced the same changes in AD. The mifepristone treatment decreased the MHC 2X profile in R. Under dexamethasone, four muscles exhibited a significantly higher proportion of the more rapid isoforms than under mifepristone. A previous work showed that controllable stress induced a marked increase in the relative expression of MHC 2B in the same skeletal muscles (Martrette et al. , 1998). Our results confirm then a significant participation of glucocorticoïd in MHC isoform expression during controllable stress.

  6. Jaw movement alters the reaction of human jaw muscles to incisor stimulation.

    PubMed

    Brinkworth, Russell S A; Türker, Kemal S

    2005-07-01

    The changes in the minimum time to consciously react (reaction time) and the order of jaw muscle recruitment to precisely controlled axial stimulation of the incisors during controlled jaw movements are not known. To this end, ten subjects were recruited to investigate the reaction time of bilateral temporalis and masseter muscles and bite force. Stimuli were delivered axially to the upper central incisors during active jaw closing and opening, and under static conditions. The results showed that the reaction time was increased an average of 35% during both jaw opening and closing movements when compared with static jaw conditions. The left temporalis was recruited approximately 10 ms before the right temporalis, whereas no significant side differences were found between the masseter muscles. The masseter muscles were recruited an average of 20 ms before the temporalis muscles during jaw closing, but no difference existed during opening. Under static conditions the reaction time in the bite force was approximately 16 ms longer than the left temporalis, but was not significantly different from the reaction time of any of the other muscles, indicating that, under the static conditions tested, the left temporalis was more often responsible for initiation of the mechanical reactions in the jaw. Because of active compensation, no force measurements were made during jaw movement. This study is a prerequisite for investigations into the modulation of reflexes during jaw movement, because a response to a stimulus commencing after the minimum reaction time may not be entirely reflex in origin.

  7. The influence of the position of surface recording electrodes on the relative uptake of the masseteric and temporal M-responses in man.

    PubMed

    Macaluso, G M; De Laat, A

    1995-12-01

    The present report aimed at evaluating the influence of recording conditions on the relative uptake of direct motor responses obtained in the masseter and temporalis muscles after electrical stimulation of their nerves, using a monopolar needle technique. In 10 subjects, various surface electromyographic recording set-ups were compared using supramaximal M-responses. Volume-conducted potentials originating from the masseter muscle could be recorded from the neck. For the masseter muscle, the optimal position for the active recording electrode was over the anterior and inferior part of the muscle belly. The configuration of the masseter M-response recorded from various positions over the muscle belly was highly variable both intra- and interindividually. The configuration of the M-response of the anterior part of the temporalis muscle showed less variability.

  8. 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.

  9. Bilateral trigeminal nerve paralysis and Horner's syndrome associated with myelomonocytic neoplasia in a dog.

    PubMed

    Carpenter, J L; King, N W; Abrams, K L

    1987-12-15

    A 5-year-old male Doberman Pinscher had nasal stenosis, dropped mandible, bilateral atrophy of masseter and temporalis muscles, and Horner's syndrome caused by aleukemic myelomonocytic leukemia. Neoplastic cellular neurotropism, diffuse turbinate and nodular peribronchial infiltrate, and a hepatic portal infiltrative pattern similar to that of lymphoma were microscopic features of interest.

  10. Correlation between skin surface temperature over masticatory muscles and pain intensity in women with myogenous temporomandibular disorder.

    PubMed

    Dibai-Filho, Almir Vieira; Costa, Ana Cláudia de Souza; Packer, Amanda Carine; Rodrigues-Bigaton, Delaine

    2013-01-01

    Pain is a common clinical manifestation in individuals with temporomandibular disorder (TMD). The literature report changes in microcirculation in this condition. The aim of the present study was to correlate skin surface temperature at the central point of the masticatory muscles with pain intensity in women with myogenous TMD. The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and the visual analogue scale (VAS) were used to divide 40 female university students into four groups: control group (n=10), mild pain group (n=10), moderate pain group (n=10) and severe pain group (n=10). Infrared thermography was used to assess the masticatory muscles. No significant correlations were found between pain intensity and skin surface temperature over the left masseter (p=0.368), right masseter (p=0.618), left anterior temporalis (p=0.293) and right anterior temporalis (p=0.922) muscles. No correlations were found between pain intensity and asymmetry of the masseter (p=0.375) and anterior temporalis (p=0.090) muscles. Moreover, no significant difference in skin surface temperature (p> 0.05) was found among the different groups. Pain intensity in women with myogenous TMD was not associated with skin surface temperature at the central point of the masseter and anterior temporalis muscles.

  11. Traumatic myositis ossificans in masticatory muscles.

    PubMed

    Lello, G E; Makek, M

    1986-08-01

    3 cases of traumatic myositis ossificans circumscripta, located within the masticatory muscles are presented. Two of the lesions involved the masseter muscle, and exceptionally, 1 involved the temporalis muscle. Three pathognomonic histological zones, permitting the differential diagnosis of myositis ossificans from sarcomatous lesions, are described, and treatment incorporating ideally early surgical intervention with wide excisional biopsy of the lesion is stressed.

  12. Reliability of EMG activity versus bite-force from human masticatory muscles

    PubMed Central

    Gonzalez, Y.; Iwasaki, L.R.; McCall, W.D.; Ohrbach, R.; Lozier, E.; Nickel, J.C.

    2011-01-01

    The reproducibility of electromyographic (EMG) activity in relation to static bite-force from masticatory muscles for a given biting situation is largely unknown. Our aim was to evaluate the reliability of EMG activity in relation to static bite-force in humans. Eighty-four subjects produced 5 unilateral static bites of different forces at different biting positions on molars and incisors, at two separate sessions, while surface EMG activities were recorded from temporalis, masseter, and suprahyoid muscles bilaterally. Intraclass Correlation Coefficients (ICCs) were used, where an ICC of ≥ 0.60 indicated good reliability of these slopes. ICCs for jaw closing muscles during molar biting were: temporalis ipsilateral 0.58 to 0.93 and contralateral 0.88 to 0.91, masseter ipsilateral 0.75 to 0.86 and contralateral 0.69 to 0.88; while during incisor biting were: temporalis ipsilateral 0.56 to 0.81 and contralateral 0.34 to 0.86, masseter ipsilateral 0.65 to 0.78 and contralateral 0.59 to 0.80. For the suprahyoid muscles the confidence intervals were mostly wide and most included zero. Slopes of the EMG activity versus bite-force for a given biting situation were reliable for temporalis and masseter muscles. These results support the use of these outcome measurements for the estimation and validation of mechanical models of the masticatory system. PMID:21564316

  13. Surface EMG of the masticatory muscles (Part 3): Impact of changes to the dynamic occlusion.

    PubMed

    Hugger, S; Schindler, H J; Kordass, B; Hugger, A

    2013-01-01

    The third part of this literature review on the clinical relevance of surface electromyography (EMG) of the masticatory muscles summarizes the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, examining the impact of changes to the dynamic occlusion. Clenching in left and right laterotrusive positions results in decrease in EMG activity of masseter and temporalis muscles on both working and non-working side. Masseter muscle exhibits largely uniform bilateral activity in laterotrusive positions, independent of canine guidance or group function with and without non-working side contacts. There is a dominance of temporalis muscle activity on the working side and, in case of posterior contacts and balancing contacts, temporalis muscle activity increases and changes from an unilateral to a symmetrical pattern.

  14. Lamination of the masticatory muscles in the Phascolarctos cinereus (Koala) according to their innervations.

    PubMed

    Nakajima, Koh; Townsend, Grant

    2009-05-01

    The masticatory muscles are usually classified into four groups: masseter, temporalis, lateral pterygoid and medial pterygoid. The communicating muscle bundle between the temporalis and masseter called the zygomaticomandibular muscle exists. The laminations within these muscles are commonly separated by aponeuroses. Nerves control the action of muscles, so improved understanding about innervation patterns in the masticatory muscles is important in the consideration of muscle function. In this study, we focus on the relationships between the nerves supply and the lamination of masticatory muscles in Phascolarctos cinereus (Koala). The masseter muscle consists of superficial and deep muscle layers. The superficial muscle layer of the masseter muscle is divided into rostro-lateral and caudo-internal nerve layers. The deep muscle layer of the masseter muscle is divided into rostral, rostro-lateral, medial and caudo-internal nerve layers. The nerves that innervate the zygomaticomandibular muscle are distributed to the lateral area of the coronoid process. The temporalis muscle was divided into internal layer of the coronoid process, a lateral layer of the coronoid process and a posterior layer by the nerve distribution pattern. The medial pterygoid muscle divided into rostro-internal, medial and caudo-lateral nerve layers.

  15. Efficacy of botulinum toxin therapy in treatment of myofascial pain.

    PubMed

    Chaurand, Jorge; Pacheco-Ruíz, Laura; Orozco-Saldívar, Hector; López-Valdés, Julio

    2017-01-01

    The present study aimed to assess the efficacy of using botulinum toxin (BTX) in temporomandibular joint disorders, particularly pertaining to myofascial pain from masseter and temporal muscles. The study included 11 patients who were diagnosed with masseter and temporalis myofascial pain. Visual analog scale for pain and pressure algometry were conducted initially, after 1 month of conservative therapy (control group), and after 1 month of BTX type A injections (study group). Data were statistically analyzed (analysis of variance and Wilcoxon's test) to determine intergroup differences. Both conservative therapy and BTX injections showed reduction in pain scores and increase in pain threshold compared with baseline, and statistically significant differences were noted between both groups. Thus, BTX injections appear to be effective in management of chronic myofascial pain targeting masseter and temporalis muscles.

  16. The function of the disco-muscular apparatus in the human temporomandibular joint.

    PubMed

    Bade, H

    1999-01-01

    The morphology and function of the disco-muscular apparatus of the human TMJ is a controversial subject. Connections between the muscles which move the mandible and the "disco-capsular complex" have been described in a contradictory way. The disco-muscular apparatus is also described as being more extensive than that of the M. pterygoideus alone to include to the Mm. temporalis and masseter. However, the involvement of the latter is considered to be a peripheral variation of the normal anatomy and of little, if any, functional significance. The existence of independent relationships between the deep portions of the masseter and temporal muscles and the disco-capsular apparatus of the human TMJ is rarely discussed or explained. The morphologic findings were derived from fixed and unfixed human temporomandibular joints (TMJ) of varying ages and both sexes, whereby the functional maturity of the masticatory apparatus was taken into consideration. The results of the study show that aside from fibers originating from the superior venter of the M. pterygoideus lateralis, additional muscle or connective tissue fibers from the perimysium of the M. masseter are inserted to varying extents into the disc. The same is true for the M. temporalis, which is also directly connected to the disc via muscular or fibrous elements, or indirectly via fibers from the M. masseter. The insertion of the M. pterygoideus lateralis is always in the medial portion of the Discus articularis and those of the Mm. temporalis and masseter in the middle and lateral portions of the disc respectively. It is highly probable that a direct force transfer through the Mm. temporalis and masseter to the articular disc takes place, and that these muscles contribute to the movement of the disc during jaw movement, whereas the size and form of the muscle insertions are subject to a great deal of individual variation.

  17. Architecture of the human jaw-closing and jaw-opening muscles.

    PubMed

    Van Eijden, T M; Korfage, J A; Brugman, P

    1997-07-01

    The human jaw-closing and jaw-opening muscles produce forces leading to the development of three-dimensional bite and chewing forces and to three-dimensional movements of the jaw. The length of the sarcomeres is a major determinant for both force and velocity, and the maximal work, force, and shortening range each muscle is capable of producing are proportional to the architectural parameter volume, physiological cross-sectional area, and fiber length, respectively. In addition, the mechanical role the muscles play is strongly related to their three-dimensional position and orientation in the muscle-bone-joint system. The objective of this study was to compare relevant architectural characteristics for the jaw-closing and jaw-opening muscles and to provide a set of data that can be used in biomechanical modeling of the masticatory system. In eight cadavers, sarcomere lengths, muscle masses, fiber lengths, pennation angles, and physiological cross-sectional areas were determined for the following muscles: superficial and deep masseter, anterior and posterior temporalis, anterior and posterior medial pterygoid, inferior and superior lateral pterygoid, posterior and anterior digastric, geniohyoid, posterior and anterior mylohyoid, and stylohyoid. To determine the spatial position of their action lines, the three-dimensional coordinates of the attachment sites were registered. Compared with the jaw openers, the jaw closers were characterized by shorter sarcomere lengths at the closed jaw, larger masses of contractile and tendinous tissue, larger physiological cross-sectional areas, larger pennation angles, shorter fiber lengths, shorter moment arms, and lower fiber-length-to-muscle-length ratios. In addition, architectural features differed across the muscles of the same functional group. Sarcomere length did not differ significantly among the regions of the same muscle. In contrast, in some muscles, significant intramuscular differences were found with respect to, e

  18. Indications for jaw gape-related control of relative muscle activation in sequent chewing strokes.

    PubMed

    Pröschel, P A; Morneburg, T R

    2010-03-01

    Jaw muscle activity ratios in unilateral isometric biting differ from ratios of unilateral chewing but approach the latter if the jaw gape in biting is made as small as the minimum interocclusal distance (MID) of chewing. Especially, the masseter working/balancing side ratio (W/B-ratio) becomes as asymmetric as in chewing, because of reduction in balancing side (BS) masseter activity. This behaviour of ratios might reflect a 'chewing-specific' motor strategy induced when isometric biting is performed with a 'chewing-like' gape. If this hypothesis applies, activity ratios should be associated with MIDs of sequent chewing strokes in a similar manner as with incremented jaw gapes in isometric biting. To test this prediction, bilateral surface electromyograms of masseter and anterior temporalis muscles and incisor movements were recorded during unilateral chewing in 52 subjects. W/B-ratios of masseter and temporalis activities and temporalis/masseter-ratios on both sides were calculated. The ratios were related to MIDs of consecutive chewing cycles. Three of the four ratios were associated with masticatory MID in the same manner as with jaw gape in isometric biting. In particular with decreasing MID, the masseter W/B-ratio increased from 1.5 to 2.2 (P < 0.01). This increase in asymmetry was attributed to a stronger decrease in masseter activity on the BS than on the working side. We conclude that relative jaw muscle activation is associated with interocclusal distance in a similar way in isometric biting and in chewing. This analogy supports the idea of a common jaw gape-related neuromuscular strategy facilitated by afferent signalling of interocclusal distance.

  19. 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

  20. Surface electromyographic assessment of patients with long lasting temporomandibular joint disorder pain.

    PubMed

    Tartaglia, Gianluca M; Lodetti, Gianluigi; Paiva, Guiovaldo; De Felicio, Claudia Maria; Sforza, Chiarella

    2011-08-01

    The normalized electromyographic characteristics of masticatory muscles in patients with temporomandibular joint disorders (TMD) and healthy controls were compared. Thirty TMD patients (15 men, 15 women, mean age 23 years) with long lasting pain (more than 6 months), and 20 control subjects matched for sex and age were examined. All patients had arthrogenous TMD according to the Research Diagnostic Criteria for TMD (RDC/TMD). Surface electromyography of masseter and temporal muscles was performed during maximum teeth clenching either on cotton rolls or in intercuspal position. Standardized EMG indices and the median power frequency were obtained, and compared between the two groups and sexes using ANOVAs. During clenching, the TMD patients had larger asymmetry in their temporalis muscles, larger temporalis activity relative to masseter, and reduced mean power frequencies than the control subjects (p<0.05, ANOVA). In both groups, the mean power frequencies of the temporalis muscles were larger than those of the masseter muscles (p<0.001). No sex related differences, and no sex × group interactions were found. In conclusion, young adult patients with long lasting TMD have an increased and more asymmetric standardized activity of their temporalis anterior muscle, and reduced mean power frequencies, relative to healthy controls.

  1. Modulation of the stretch reflex of jaw-closing muscles in different modes and phases of respiration.

    PubMed

    Otani-Saito, K; Ono, T; Ishiwata, Y; Kuroda, T

    2001-06-01

    The objective of this study was to investigate whether and how changes in the mode of respiration affect the electromyographic activity of human jaw-closing muscles. Fifteen men were examined in this study. A pair of surface electrodes was attached bilaterally to the masseter and anterior and posterior temporalis muscles for electromyographic recording. Respiratory movements of the chest wall and nasal airflow were recorded simultaneously. Recordings were performed with subjects in the sitting position during quiet nasal and oral respiration. The stretch reflex of jaw-closing muscles was elicited by randomly tapping the chin with an impulse hammer. In 11 subjects, we measured nasal resistance with a rhinomanometer. The amplitude of electromyographic activities of the masseter and anterior temporalis muscles during oral respiration was significantly less than that during nasal respiration, whereas that of the posterior temporalis muscle showed no significant difference between the different modes of respiration. Furthermore, the reduction in the amplitude of the electromyographic activity was more evident in the inspiratory phase during oral respiration. There was a significant positive correlation between the ratio of the reflex amplitude during inspiration in the 2 respiratory modes and nasal resistance for the masseter muscle, but not for the anterior temporalis muscle. These results suggest that the reflexive electromyographic activity of some human jaw-closing muscles is modulated during oral respiration.

  2. The influence of occlusion on jaw and neck muscle activity: a surface EMG study in healthy young adults.

    PubMed

    Ferrario, V F; Tartaglia, G M; Galletta, A; Grassi, G P; Sforza, C

    2006-05-01

    The electromyographic (EMG) characteristics of masseter, temporalis and sternocleidomastoid (SCM) muscles during maximum voluntary teeth clench were assessed in 27 male and 35 female healthy young adults. Subjects were divided into two groups: (i) 'complete' Angle Class I (bilateral, symmetric canine and molar Class I relationships), and (ii) 'partial' Angle Class I (one to three canine/molar Class I relationships, the remaining relationships were Class II or Class III). On average, standardized muscular symmetry ranged 80.7-87.9%. During maximum voluntary teeth clench, average co-contraction of SCM muscle was 13.7-23.5% of its maximum contraction. On average, all torque coefficients (potential lateral displacing component) were >90%, while all antero-posterior coefficients (relative activities of masseter and temporalis muscles) were >85%. The average integrated areas of the masseter and temporalis EMG potentials over time ranged 87.4-106.8 muV/muV s%. Standardized contractile muscular activities did not differ between 'complete' and 'partial' Angle Class I, and between sexes (two-way analysis of variance). A trend toward a larger intragroup variability in EMG indices was observed in the subjects with 'partial' Angle Class I than in those with 'complete' Angle Class I (significant difference for the temporalis muscle symmetry, P = 0.013, analysis of variance). In conclusion, the presence of a complete or partial Angle occlusal Class I did not seem to influence the standardized contractile activities of masseter, temporalis and SCM muscles during a maximum voluntary clench. Subjects with a 'complete' Angle Class I were somewhat a more homogenous group than subjects with 'partial' Angle Class I.

  3. Dual innervation method using one-stage reconstruction with free latissimus dorsi muscle transfer for re-animation of established facial paralysis: simultaneous reinnervation of the ipsilateral masseter motor nerve and the contralateral facial nerve to improve the quality of smile and emotional facial expressions.

    PubMed

    Watanabe, Yorikatsu; Akizuki, Tanetaka; Ozawa, Tsuyoshi; Yoshimura, Kei; Agawa, Kaori; Ota, Tomoyuki

    2009-12-01

    One-stage microneurovascular free muscle transfer is a common surgical procedure for re-animation of established facial paralysis. However, innervation of the transferred muscle by the contralateral facial nerve prevents smile and other facial expressions on one side, and reinnervation requires about 7 months. To overcome these drawbacks, we report a dual innervation method using one-stage reconstruction with free latissimus dorsi muscle transfer. Three patients were treated with the dual innervation method, which is based on the one-stage method with some modifications: the soft tissue present over the ipsilateral masseter muscle and the hilum where the thoracodorsal nerve proceeds into the muscle segment is removed; the muscle is harvested to locate the hilum in the cranial one-third of the segment; and the muscle is transferred to the malar pocket of the paralysed face such that the hilum contacts the masseter muscle. On average, muscle movement was recognised on voluntary biting at 3.4 months and on spontaneous smiling at 5.9 months after surgery. A dual innervation sign was recorded on electromyographs 6.4 months after surgery. The patients developed a spontaneous symmetrical smile and facial expressions on one side with minimum synkinesis after postoperative mirror rehabilitation. The advantages of the dual innervation method include faster reinnervation of the transferred muscle compared to one-stage options; achievement of spontaneous smile and voluntary smile on each side; augmentation of neural signals to the muscle for more symmetrical smiling; minimum synkinesis of the transferred muscle on biting for eyelid closure and emotional facial re-animation through a learning program to enhance cerebral cortical reorganisation.

  4. Increased sternocleidomastoid, but not trapezius, muscle activity in response to increased chewing load.

    PubMed

    Häggman-Henrikson, Birgitta; Nordh, Erik; Eriksson, Per-Olof

    2013-10-01

    Previous findings, during chewing, that boluses of larger size and harder texture result in larger amplitudes of both mandibular and head-neck movements suggest a relationship between increased chewing load and incremental recruitment of jaw and neck muscles. The present report evaluated jaw (masseter and digastric) and neck [sternocleidomastoid (SCM) and trapezius] muscle activity during the chewing of test foods of different sizes and textures by 10 healthy subjects. Muscle activity was recorded by surface electromyography and simultaneous mandibular and head movements were recorded using an optoelectronic technique. Each subject performed continuous jaw-opening/jaw-closing movements whilst chewing small and large boluses of chewing gum and rubber silicone (Optosil). For jaw opening/jaw closing without a bolus, SCM activity was recorded for jaw opening concomitantly with digastric activity. During chewing, SCM activity was recorded for jaw closing concomitantly with masseter activity. Trapezius activity was present in some, but not all, cycles. For the masseter and SCM muscles, higher activity was seen with larger test foods, suggesting increased demand and recruitment of these muscles in response to an increased chewing load. This result reinforces the previous notion of a close functional connection between the jaw and the neck motor systems in jaw actions and has scientific and clinical significance for studying jaw function and dysfunction.

  5. The functional significance of the squamosal suture in Australopithecus boisei.

    PubMed

    Rak, Y

    1978-07-01

    A juvenile Australopithecus boisei specimen from the Omo basin, southern Ethiopia, is found to exhibit and extraordinarily large overlap of the temporal squama on the parietal, a phenomenon shared with at least two adult specimens of A. boisei. An attempt is made to interpret the overlap as a structural (bony/ligamentous) adaptation necessitated by the unique combination of certain components of the masticatory system of A. boisei. These are: (1) the massiveness and strength of the temporalis muscle, (2) its relatively anterior location, and (3) the lateral position of the masseter muscle due to the flaring of the zygomatic arches. The effect of the temporalis muscle is to create excessive pressure on the portion of the squamosal suture along the parietal, while the lateral placement of the masseter and the resultant increase of pressure on the temporal squama via the zygomatic arch tend to "loosen" the contact between the temporal and parietal bones.

  6. Aesthetic Treatment of Bruxism

    PubMed Central

    Aguilera, Shino Bay; Perico, Viviana Andrea

    2017-01-01

    Bruxism is a diurnal or nocturnal parafunctional activity that includes unconscious clenching, grinding, or bracing of the teeth. An extensive medical history should be taken in these patients so proper diagnosis can be made. Habits such as biting the tongue, cheeks or lips, chewing gum or eating seeds for many hours per day, biting nails, and/or biting hard objects, will cause and/or exacerbate pre-existing bruxism. The etiology of bruxism is uncertain, but it is hypothesized to be associated with genetic, structural, and psychosocial factors. Over time, chronic clenching of the jaw leads to hypertrophy of masseters and temporalis musculature causing the face to take on a masculine and square appearance. Patients commonly present to dermatology cosmetic practices wishing to have a more slim, softer appearing face. This review is the first paper to discuss aesthetic treatment options for complications of bruxism including masseter and temporalis hypertrophy and the associated accelerated aging of the lower face. PMID:28670358

  7. The role of masticatory muscles in the continuous loading of the mandible

    PubMed Central

    de Jong, W C; Korfage, J A M; Langenbach, G E J

    2011-01-01

    Muscles are considered to play an important role in the ongoing daily loading of bone, especially in the masticatory apparatus. Currently, there are no measurements describing this role over longer periods of time. We made simultaneous and wireless in vivo recordings of habitual strains of the rabbit mandible and masseter muscle and digastric muscle activity up to ∼ 25 h. The extent to which habitually occurring bone strains were related to muscle-activity bursts in time and in amplitude is described. The data reveal the masseter muscle to load the mandible almost continuously throughout the day, either within cyclic activity bouts or with thousands of isolated muscle bursts. Mandibular strain events rarely took place without simultaneous masseter activity, whereas the digastric muscle only played a small role in loading the mandible. The average intensity of masseter-muscle activity bouts was strongly linked to the average amplitude of the concomitant bone-strain events. However, individual pairs of muscle bursts and strain events showed no relation in amplitude within cyclic loading bouts. Larger bone-strain events, presumably related to larger muscle-activity levels, had more constant principal-strain directions. Finally, muscle-to-bone force transmissions were detected to take place at frequencies up to 15 Hz. We conclude that in the ongoing habitual loading of the rabbit mandible, the masseter muscle plays an almost non-stop role. In addition, our results support the possibility that muscle activity is a source of low-amplitude, high-frequency bone loading. PMID:21492160

  8. Thermographic characterization of masticatory muscle regions in volunteers with and