Left Temporalis Research Articles

A hiperboloide não influencia a atividade eletromiográfica dos músculos mastigatórios durante movimentos mandibulares em indivíduos com disturbiotemporomandibular

Abstract Introduction The hyperboloid is a masticatory device made of silicone with an hourglass (hyperbolic) shape that has been used as an aid to jaw functional orthopedic therapy. Objective To evaluate whether the hyperboloid device affects electromyographic (EMG) activity of the masticatory muscles during jaw movements in individuals with temporomandibular joint disorders (TMD) compared to controls. Methods The study sample consisted of 49 participants divided into two groups: mild, moderate and severe TMD (TMD group; n = 25) and a control group (n = 24). We evaluated EMG activities of temporal and masseter muscles bilaterally during jaw protraction and retraction, and left and right lateralization with and without the use of the hyperboloid device. Statistical analyses were performed using two-way ANOVA with two factors: group (healthy and TMD) and situation (with or without the use of the hyperboloid). Results We found higher EMG activity in the left temporal in the TMD group and no difference in EMG activities with the use of the hyperboloid device. Conclusion The use of the hyperboloid device did not affect EMG activity of the muscles evaluated in the groups studied. We found higher EMG activity of the left temporal muscle in participants with TMD. Long-term randomized studies should be conducted in individuals with TMD to investigate the effects of functional orthopedic therapy using the hyperboloid device with visual and quantitative feedback.

Cannabinoid oilwith gabapentin for the treatment of chronicneuropathic pain– case report

A 3-year-old Leonberger was presented with unilateral atrophy of the left temporal muscle, concomitant left corneal hypoesthesia and jaw pain. Based on magnetic resonance imaging (MRI) results, a trigeminal peripheral nerve sheath tumor was presumptively diagnosed, and treatment based on volumetric modulated arc therapy combined with temozolomide was introduced. Although the tumor volume was stable, after 6 months the patient developed severe jaw pain manifested by rubbing of the face, aversion to eating, and yawning. No desirable response to combinations of meloxicam, gabapentin, tramadol/buprenorphine at their maximal tolerated doses was achieved. Only a treatment based on a commercially available nonpsychoactive cannabinoid oil – Perognidol® (Ilovet) combined with gabapentin successfully relieved the symptoms of pain within a week. Three months later, a follow-up MRI revealed a significant growth of the tumor associated with cerebral infiltration. Eventually, the general condition of the patient deteriorated. The dog was euthanized 800 days after the original diagnosis.

Development of a model to investigate the effects of prolonged ischaemia on the muscles of mastication of male Sprague Dawley rats

ObjectiveThe aims of this study were to develop a novel rodent model of masticatory muscle ischaemia via unilateral ligation of the external carotid artery (ECA), and to undertake a preliminary investigation to characterize its downstream effects on mechanosensitivity and cellular features of the masseter and temporalis muscles. DesignThe right ECA of 18 male Sprague-Dawley rats was ligated under general anaesthesia. Mechanical detection thresholds (MDTs) at the masseter and temporalis bilaterally were measured immediately before ECA ligation and after euthanasia at 10-, 20-, and 35-days (n = 6 rats/timepoint). Tissue samples from both muscles and sides were harvested for histological analyses and for assessing changes in the expression of markers of hypoxia and muscle degeneration (Hif-1α, VegfA, and Fbxo32) via real time PCR. Data were analyzed using mixed effect models and non-parametric tests. Statistical significance was set at p < 0.05. ResultsMDTs were higher in the right than left hemiface (p = 0.009) after 20 days. Histological changes indicative of muscle degeneration and fibrosis were observed in the right muscles. Hif-1α, VegfA, and Fbxo32 were more highly expressed in the masseter than temporalis muscles (all p < 0.05). Hif-1α and, VegfA did not change significantly with time in all muscles (all p > 0.05). Fbxo32 expression gradually increased in the right masseter (p = 0.024) and left temporalis (p = 0.05). ConclusionsECA ligation in rats induced hyposensitivity in the homolateral hemiface after 20 days accompanied by tissue degenerative changes. Our findings support the use of this model to study pathophysiologic mechanisms of masticatory muscle ischaemia in larger investigations.

Effects on Muscular Activity after Surgically Assisted Rapid Palatal Expansion: A Prospective Observational Study.

The study aims to investigate the modifications in the temporalis and the masseter activity in adult patients before and after SARPE (Surgically Assisted Rapid Palatal Expansion) by measuring electromyographic and electrokinesographic activity. 24 adult patients with unilateral posterior crossbite on the right side were selected from the Orthodontic Department of the University of Milan. Three electromyographic and electrokinesographic surface readings were taken respectively before surgery (T0) and 8 months after surgery (T1). The electromyographic data of both right and left masseter and anterior temporalis muscles were recorded during multiple tests: standardized maximum voluntary contraction (MVC)s, after transcutaneous electrical nerve stimulation (TENS) and at rest. T0 and T1 values were compared with paired Student’s t-test (p < 0.05). Results: Significant differences were found in the activity of right masseter (p = 0.03) and right temporalis (p = 0.02) during clench, in the evaluation of right masseter at rest (p = 0.03), also the muscular activity of masseters at rest after TENS from T0 to T1 (pr = 0.04, pl = 0.04). No significant differences were found in the activity of left masseter (p = 0.41) and left temporalis (p = 0.39) during clench and MVC, in the evaluation of left masseter at rest (p = 0.57) and in the activity during MVC of right masseter (p = 0.41), left masseter (p = 0.34), right temporalis (p = 0.51) and left temporalis (p = 0.77). Results showed that the activity of the masseter and temporalis muscles increased significantly after SARPE during rest and clenching on the side where the cross-bite was treated.

Review of cysticercosis of maxillofacial region and report of two cases

Cysticercosis is a parasitic infection caused by the larval stage of Taenia solium, which very rarely manifests in the maxillofacial region. It usually presents as a painless swelling. The most common site for maxillofacial cysticercosis are the tongue and lips. When humans accidently ingest the eggs of Taenia solium, they become the intermediate host, a role which is typically played by pig. This paper describes two cases of cysticercosis cellulosae, presenting as non-tender swelling of left buccal mucosa and left temporalis region respectively. Case reports available on PubMed were searched and a review was performed. Excision of cystic lesion was the treatment modality in majority of published reports. It is emphasised that cysticercosis should be considered in differential diagnosis of solitary painless swellings of oral and maxillofacial region, especially in patients from an endemic region.

Electromyographic values of masticatory muscles in middle-aged dentate patients

Introduction. Surface electromyography has proven to be a useful instrument for the assessment of success rate for different dental treatments. However, due to numerous variables that may influence the data like age, gender, fat tissue thickness etc. it is necessary to adjust the obtained values to a reference group with the same parameters. Material and methods. A number of 33 patients were included in the study (21 women and 12 men) aged between 43-67 years old (mean 54± SD1.26). Surface electromyography of masticatory muscles was used in these patients to assess the average value in a time span and overlapping coefficients. Totally 10 parameters from each patient were recorded: TAL, TAR, MML, MMR, PocTA, PocMM, BAR, Asym, TORS, Impact. Data were stored in an Excel spreadsheet and then analyzed statistically using RStudio software. Results. Based on the results of our study, the main EMG activity indices in middle-aged Moldavian individuals had the following values: for the left temporalis (TAL) was 42 µV, median 18.8 with a minimum of 3.8 and a maximum of 190 µV. For the right temporalis (TAR) the mean was 51.4 µV, median – 32.9, a minimal value of 7.9 and a maximum of 248 µV. The left masseter had a mean of 48.7 µV, median 12.3, a minimal value of 1.5 and a maximum value of 439 µV. The right masseter had a mean of 42.1 µV, a median of 16.3, minimum value 11.4 and maximum 243 µV. The overlapping coefficients deviated with 20.5% from the normal range provided by the manufacturer. Conclusions. Electromyographic activity of masticatory muscles in healthy patients can be used for comparison with patients that had various dental treatment but have the same age, gender, ethnicity, etc. The overlapping coefficients did not perfectly match in the normal range provided by manufacturer even if these subjects had previously minimum dental procedures.

Electromyographic Study of Masseter and Temporalis Muscles During Mastication in Children with and without Down Syndrome Aged 2-12 Years

Background and Aim: Swallowing disorder is a common and constant problem in people with Down Syndrome. In experimental method electromyography can be used to evaluate Mastication . The aim of this study was to evaluate the electromyography of the masseter and temporal muscles during Mastication in 2 to 12 years old children with Down syndrome in Arak. Material and methods: This is a descriptive-analytical and case-control study, that conducted with the purpose of electromyographic study of masseter and temporal muscles during Mastication on 15 children from available 2 to 12 years old Down Syndrome and 15 children that were matched according the method of person-to-person matching in terms of age and gender with samples with Down syndrome Ethical considerations: In this study, conscious consent was obtained from all parents and no physical harm was inflicted on individuals. Findings: About the comparison of the mean of amplitude (intensity) of electrical signal of muscle between two groups except right temporal muscle during Mastication and about the mean of the mean frequency when Mastication except for left temporal muscle, in other cases the difference was significant. In the case of comparing the median frequency of the electrical signal of the muscle in most muscles the difference was not significant. Conclusion: Mean amplitude (intensity) and frequency of the mean electrical signal of the muscle when chewing in most muscles was different between the two groups with Down syndrome and normal, but the differences in mean median frequency in most muscles were insignificant.

Validity and reliability of the Egyptian algometer in patients with bruxism

IntroductionPressure pain threshold has been quantified by using a gold standard algometer in patients with bruxism. However, the expense associated with quantifying pressure pain threshold to detect trigger points with a gold standard algometer precludes its use in the clinic. This study aimed to measure the reliability and validity of the more accessible Egyptian algometer for pressure pain threshold evaluation in patients with bruxism.MethodsA descriptive repeated-measures study was performed among 100 participants with bruxism. Pressure pain threshold values were collected from the left temporalis, right temporalis, left masseter, and right masseter muscles with the participants sitting. Pressure pain thresholds were assessed over 2 sessions separated by a 1-week interval.ResultsIntraclass correlation coefficient (ICC) determined the intra-rater reliability and Pearson correlation analysis determined the validity of the Egyptian algometer. ICC equalled 0.878, 0.785, 0.896, and 0.903 for the right masseter, left masseter, right temporalis, and left temporalis muscles, respectively. The standard error of measurement ranged from 0.24 to 0.5, the minimal detectable difference ranged from 0.66 to 1.41, ICC ranged from 0.785 to 0.903. Pearson correlation values were 0.673, 0.670, 0.408, and 0.705 for the right masseter, left masseter, right temporalis, and left temporalis muscles, respectively.ConclusionsHigh ICCs indicated a strong agreement between the measurement systems, suggesting that the Egyptian algometer is a reliable and valid device for quantification of pressure pain threshold in patients with bruxism.

Amyotrophic Lateral Sclerosis: An Analysis of the Electromyographic Fatigue of the Masticatory Muscles.

Amyotrophic lateral sclerosis is a chronic degenerative disease that affects motor neurons, thereby promoting functional changes in the human body. The study evaluated the electromyographic fatigue threshold of the masseter and temporal muscles of subjects with amyotrophic lateral sclerosis. A total of eighteen subjects were divided into two groups: amyotrophic lateral sclerosis (n=9) and disease-free control (n=9). The groups were equally divided according to gender (7 males, 2 females). The fatigue threshold was analysed using median frequencies obtained during the 5-second window (initial [IP], mid [MP], and final [FP] periods) of electromyographic signalling of the masseter and temporal muscles bilaterally, with reduction in muscle force during maximal voluntary dental clenching. Significant difference (p&lt;0.05) in the left temporal muscle: IP (p=0.05) and MP (p=0.05) periods was demonstrated. The amyotrophic lateral sclerosis group showed a decrease in median frequency of the electromyographic signal of the masseter and temporal muscles compared to the control group. Amyotrophic lateral sclerosis promotes functional impairment of the stomatognathic system, especially at the electromyographic fatigue threshold of the masticatory muscles.

Clinical, Electromyographical and Radiological Comparison of Dawson’s Bimanual Technique of Guiding the Mandible with Wax Ball Orientation Technique©

Introduction: There are numerous methods to guide the mandible into Centric Relation (CR). The Dawson’s bimanual technique is a time tested and established method to guide the mandible into CR. On the other hand the author of this study also has copyrighted a technique (wax ball orientation technique©) to guide the mandible into CR. Hence, this methodological study was performed to compare the two CR techniques to guide the mandible in CR position using clinical, myographical and radiological assessment methods. Aim: To compare and assess which amongst the two (Dawson’s bimanual technique and wax ball orientation technique) CR guiding techniques best guides the mandible to CR position using clinical, electromyographical and radiological assessment methods. Materials and Methods: This interventional and clinical study was conducted at School of Dental Sciences, KIMSDU, Karad, Maharashtra, India, from May 2019 to May 2020. The study included healthy dentate individuals having Angle’s class I malocclusion without any occlusal interferences and an intact dentition except for 3rd molars. Two CR technique to guide the mandible were technique 1-Dawson’s bimanual technique and technique 2 - wax ball orientation technique. The study was carried out in three phases: clinical, electromyographical and radiological. Difference between the centric points, workload on elevators, condylar position was statistically analysed. Descriptive statistics was used to analyse the difference between the centric points marked using both the techniques. Independent t-test was applied to compare the gender and the mean centric distribution. Results: Among the 45 study subjects considered for the study, 32 were females and 13 were males with the mean age of 21 years. No statistically significance difference was observed between the two techniques. Paired t-test showed that workload on elevators of both sides, Right Masseter in technique 1 and 2 had p-value= 0.088, left Masseter in technique 1 and 2 had p-value= 0.3, Right temporalis in technique 1 and 2 had p-value= 0.463, left temporalis in technique 1 and 2 had p-value= 0.429. There was difference between the Anteroposterior (AP) and Superoinferior (SI) position of condyle in relation to the fossa. AP measurement in the right side in tech 1 and 2 with p-value= 0.448, AP measurement in the left side in tech 1 and 2 with p-value= 0.178, SI measurement in the right side in tech 1 and 2 had p-value= 0.803, SI measurement in the left side in tech 1 and 2 had p-value= 0.259, which were statistically insignificant. Multivariate test showed statistically significant difference between gender and EMG, results whereas it was insignificant in Magnetic Resonance Imaging (MRI). Conclusion: The wax ball technique has similar accuracy as the Dawson’s Bimanual technique.

The Association between Symmetrical or Asymmetrical High-Arched Feet and Muscle Fatigue in Young Women

The foot arches are responsible for proper foot loading, optimal force distribution, and transmission throughout the soft tissues. Since the foot arch is an elastic structure, able to adapt to forces transmitted by the foot, it was reported that low arch is related to excessive foot pronation, while high arched foot is more rigid and inflexible. Therefore, it is also probable, that foot arch alterations may change the force transmission via myofascial chains. The objective of this study was to evaluate the effect of symmetrical and asymmetrical excessive feet arching on muscle fatigue in the distal body parts such as the lower limbs, trunk, and head. Seventy-seven women (25.15 ± 5.97 years old, 62 ± 10 kg, 167 ± 4 cm) were assigned to three groups according to the foot arch index (Group 1—both feet with normal arch, Group 2—one foot with normal arch and the other high-arched, Group 3—both feet with high-arch). The bioelectrical activity of the right and left hamstrings muscles, erector spine, masseter, and temporalis muscle was recorded by sEMG during the isometric contraction lasting for 60 s. The stable intensity of the muscle isometric contraction was kept for all the time during the measurement. Mean frequency difference (%), slope (Hz), and intercept (Hz) values were calculated for muscle fatigue evaluation. No differences were observed in fatigue variables for all evaluated muscles between the right and left side in women with symmetrical foot arches, but in the group with asymmetric foot arches, the higher muscle fatigue on the normal-arched side compared to the high-arched side was noted. Significantly greater values of the semitendinosus—semimembranosus muscle frequency difference was observed on the normal-arched side compared to the high-arched side (p = 0.04; ES = 0.52; −29.5 ± 9.1% vs. −24.9 ± 8.4%). In the group with asymmetric foot arches, a significantly higher value of lumbar erector spinae muscle frequency slope (p = 0.01; ES = 1.32; −0.20 ± 0.04 Hz vs. −0.14 ± 0.05 Hz) and frequency difference (p = 0.04; ES = 0.92; −7.8 ± 3.1% vs. −4.8 ± 3.4%) were observed on the high-arched foot side compared to the side with normal foot arching. The thoracic erector spine muscle frequency slope was significantly larger in women with asymmetrical arches than in those with both feet high-arched (right side: p = 0.01; ES = 1.25; −0.20 ± 0.08 Hz vs. −0.10 ± 0.08 Hz); (left side: p = 0.005; ES = 1,17; −0.19 ± 0.04 Hz vs. −0.13 ± 0.06 Hz) and compared to those with normal feet arches (right side: p = 0.02; ES = 0.58; −0.20 ± 0.08 Hz vs. −0.15 ± 0.09 Hz); (left side: p = 0.005; ES = 0.87; −0.19 ± 0.04 Hz vs. −0.14 ± 0.07 Hz). In the group with asymmetric foot arches, the frequency difference was significantly higher compared to those with both feet high-arched (right side: p = 0.01; ES = 0.87; −15.4 ± 6.8% vs. 10.4 ± 4.3%); (left side: p = 0.01; ES = 0.96; 16.1 ± 6.5% vs. 11.1 ± 3.4%). In the group with asymmetric foot arches, a significantly higher value of the masseter muscle frequency difference was observed on the high-arched side compared to the normal-arched side (p = 0.01; ES = 0.95; 6.91 ± 4.1% vs. 3.62 ± 2.8%). A little increase in the longitudinal arch of the foot, even though such is often not considered as pathological, may cause visible changes in muscle function, demonstrated as elevated signs of muscles fatigue. This study suggests that the consequences of foot high-arching may be present in distal body parts. Any alterations of the foot arch should be considered as a potential foot defect, and due to preventing muscle overloading, some corrective exercises or/and corrective insoles for shoes should be used. It can potentially reduce both foot overload and distant structures overload, which may diminish musculoskeletal system pain and dysfunctions.

Functional interaction of chewing muscles in children with dentoalveolar system anomalies

Relevance. The focus of modern dental treatment not only on the elimination of aesthetic, but also functional disorders requires an understanding of the functional conjugation of the chewing muscles, the possibility of interprognosis of parameters. Objective. Assess the functional relationship between the tone of the chewing muscles proper and the bioelectric activity of the temporal and sublingual muscle groups in children with anomalies of the dentoalveolar system. Materials and Methods. The study involved 36 patients of Childrens Clinical Dental Clinic No. 2 of Voronezh, aged 6 to 12 years, who had not previously received orthodontic treatment and had distal occlusion anomalies. Evaluation of the bioelectric activity of temporal and sublingual muscles was carried out using surface electromyography on the Electromyograph Dental apparatus (Taganrog, Russia), the Chewing General sample. Evaluation of the tone of the chewing muscles proper was carried out using the Mioton-3C device in a state of physiological rest of the lower jaw. Statistical processing was carried out using Microsoft Excel, version 7.0 and the statistical programs SPSS Statistics 21 and STATISTICA 7. Results and Discussion. Correlation analysis revealed the presence of 4 weak positive, 2 weak negative, 14 moderate positive, 3 moderate negative, and 1 noticeable positive correlation between the tone of the right chewing muscle proper and the parameters of the bioelectric activity of the right and left temporal and sublingual muscles. Correlation analysis revealed the presence of 5 weak positive, 7 weak negative, 9 moderate negative correlations between the tone of the left chewing muscle proper and the parameters of bioelectric activity of the right and left temporal and sublingual muscles. Conclusion. A greater effect of the tone of the right chewing muscle on the bioelectric activity of temporal and sublingual muscles was found compared to the tone of the left chewing muscle itself. 27 equations have been derived that can be used as predictive models for calculating the tone of right and left chewing muscles proper depending on the indicators of bioelectric activity of temporal and sublingual muscles.

Assessment of the bioelectric activity of the masticatory muscles in orthopedic treatment with partial removable plate prostheses

Relevance. According to a number of authors, it is known that full adaptation to complete removable dentures occurs within 3 months [3–5, 9]. The main criterion for patients getting used to removable dentures is the synchronization of the work of the masticatory muscles and, as a consequence, the normalization of the chewing function. The aim of the study was to evaluate the bioelectrical activity of the masticatory muscles in patients using the CSPP.Materials and methods. In patients of the control (n = 23) and main (n = 63) groups, electromyographic examination was performed using the electroneuromyographic system "Synapsis" (Neurotechnology, Russia). Registration of the bioelectric activity of the chewing muscles was carried out directly on the day of applying the prostheses, after 1 and 3 months, respectively.Results and discussion. The electromyographic indices of the masticatory muscles in the patients of the control group decreased within one month after the treatment and amounted to 231 ± 18.2 μV for the right and 229 ± 16.1 μV for the left proper chewing muscles. The values were also reduced for the right and left temporal muscles – 228 ± 15.2 μV and 225 ± 24.1 μV (p &lt; 0.05). It should be noted that the electromyographic parameters in patients of the main group were comparable to the lower limit of the norm and amounted to 269 ± 16.5 μV and 256 ± 20.4 μV, respectively, after one month of treatment.Conclusions. In the treatment of dysfunction of the temporomandibular joint with the use of thermoplastic prostheses, an increase in the biopotentials of the masticatory muscles is observed. In the orthopedic treatment of patients with terminal dentition defects using thermoplastic prostheses, the electromyographic parameters of the masticatory muscles are most close to normal after 3 months of using these prostheses.

The Influence of Visual Input on Electromyographic Patterns of Masticatory and Cervical Spine Muscles in Subjects with Myopia.

This study aimed to analyze the change of visual input on electromyographic patterns of masticatory and cervical spine muscles in subjects with myopia. After applying the inclusion criteria, 50 subjects (18 males and 32 females) with myopia ranging from −0.5 to −5.75 Diopters (D), were included in the study. Four muscle pairs were analyzed: the anterior part of the temporalis muscle (TA), the superficial part of the masseter muscle (MM), the anterior belly of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle belly (SCM) during resting and functional activity. Statistical analysis showed a significant decrease within functional indices (FCI) for the sternocleidomastoid muscle (FCI SCM R, FCI SCM L, FCI SCM total) during clenching in the intercuspal position with eyes closed compared to eyes open. During maximum mouth opening, a statistically significant increase of functional opening index for the left temporalis muscle (FOI TA L) was observed. Within the activity index (AcI), there was a statistically significant decrease during clenching on dental cotton rollers with eyes closed compared to eyes open.

Bite Force, Thickness, and Thermographic Patterns of Masticatory Muscles Post-Hemorrhagic Stroke

ObjectiveStroke is a neurological deficit of cerebrovascular origin, considered a 21st-century epidemic that causes functional changes in the human body. This study aimed to evaluate the stomatognathic system of patients after hemorrhagic stroke through the bite force, thickness, and skin temperature in the region of the masseter and temporalis muscles. Material and MethodsTwenty-four subjects were divided into groups: post-hemorrhagic stroke; with right side of the affected body (n = 12) and without the neurological disorder (n = 12). Maximum molar bite force was verified using a digital dynamometer. Muscle thickness was measured using ultrasound images obtained at rest and during maximal voluntary contraction of the masseter and temporalis muscles. Thermographic camera was used to record the thermographic patterns of the masseter and temporalis muscles. Data were subjected to Student's t-test (P < .05). ResultsThe maximum molar bite force showed significant differences in the right (P = .04) and left (P = .03) sides, with a reduction in force in the post-hemorrhagic stroke group on the affected and unaffected sides. There was a significant difference (P < .05) in the thickness of the left temporal muscle at mandibular rest (P = .01) between groups. The post-hemorrhagic stroke group clinically presented greater muscle thickness in almost 100% of the muscles evaluated in both clinical conditions. There were no significant differences in skin temperature in the masseter and temporal muscles between the groups. ConclusionsOur results suggest functional changes in the stomatognathic system of subjects after a hemorrhagic stroke, especially concerning molar bite force and masticatory muscle thickness in the temporal muscle (unaffected side).

Immediate effects of rhythmic joint mobilization of the temporomandibular joint on pain, mouth opening and electromyographic activity in patients with temporomandibular disorders

BackgroundRhythmic joint mobilizations (RJM) of the temporomandibular joint (TMJ) are employed to relieve pain and improve function in patients with temporomandibular disorders (TMD). However, the evidence on the immediate effects of RJM in patients with TMD is scarce. The aim of this study was to assess the immediate clinical and functional effects of RJM in patients with TMD. Materials and methodsThis was a one-group quasi-experimental before and after study. Thirty-eight patients with TMD were assessed by means of pain intensity (visual analogue score, VAS), pressure pain threshold (PPT, measured through pressure algometry on the masseter and temporal muscles), mouth opening (MO, measured with a ruler), and surface electromyographic activity of the masseter and temporal muscles (asymmetry index, AI). Measurements were performed before and after a single, 1-min session of RJM of each TMJ. All statistical analyses were performed using the SPSS version 20.0 statistical package. ResultsA statistical significant difference was found in pain intensity, PPT and MO after the intervention (p < 0.05). No difference was found in the AI. A large effect size was observed for pain intensity, PPT of the left and right masseter muscles and MO (d = 0.85–1.13), whereas for the left and right temporal muscles the effect size was moderate (d = 0.62) and small, respectively (d = 0.49). ConclusionIn this sample of patients with TMD, a single session of RJM of the TMJ seemed to be effective in reducing pain intensity, increasing PPT and improving MO immediately after the intervention, without differences in the AI.

Changes in Masticatory Muscles following orthognathic surgery (BSSO for correction of skeletal class III deformity )

Aim: To evaluate the postoperative electromyographic changes of temporalis and masseter muscles activity, in patients with orthognathic surgery BSSO,for correction of mandibular prognathism. Material and Methods: Eight adult patients,their ages ranged from 22-45 years,five females and three males ,suffering from mandibular prognathism. underwent BSSO,for performing mandibular setback . EMG examinations(peak to peak amplitude,for detection of the strength of contraction of both temporalis and masseter muscles) were done presurgical and twelve months postoperatively. Results: Significant increase in peak-to-peak amplitude values of both temporalis muscles was founded. Moreover, an increase in peak-to-peak amplitude values of both masseter muscles was found,.No significant differences were found in the mean frequency score (as one of the variables of the EMG measurement) of the masseter muscles before bilateral sagittal split osteotomy and that undertaken 12 months after bilateral sagittal split osteotomy (P = 0.06). An increase in the mean peak to peak amplitude score for the right and left temporalis muscle was found, with significant differences between the measurement found 12 months after bilateral sagittal split osteotomy, and that measured before bilateral sagittal split osteotomy fig (6) (P = 0.002,0.0001 respectively) Conclusion: No change in the strength of contraction of both temporalis and masseter muscle had detected after performing BSSO for correction of mandibular prognathism ,as detected by EMG examination.

Algorithm for analyzing the movement pattern of the temporomandibular joint musculararticular system based on multichannel electromyogram processing

Musculoskeletal system disorders is one of the priority directions in dentistry. They can manifest as Kosten's syndrome, snapping jaw, painful dysfunction syndrome, increased tooth abrasion, splits, breaks, pain and spasms in muscles, etc. The study set the following objectives: to develop an algorithm for analyzing the movement pattern of the muscular-articular system by developing an algorithm for recording, analyzing, filtering and processing multichannel electromyograms of the maxillofacial muscles. Analysis of the proposed algorithm for processing multichannel electromyograms showed that 7.2 % of multichannel electromyograms could not be analyzed due to patients' violations of the movement algorithm; 8.7 % of electromyogram checkpoint values were corrected. The group without dysfunctions of the temporomandibular joint is characterized by the prevalence of the relaxation coefficient of the left temporal muscle over the coefficient of the right muscle. The dysfunctioned group has the opposite result. The value of the compression ratio of the temporal muscles exceeding 2.5 is typical for the group with dysfunctions of the temporomandibular joint. The studied groups differ as much as possible when analyzing the relaxation coefficients of the temporal muscles. When analyzing this coefficient, it was possible to truly determine the presence or absence of violations in 50 %, falsely – in 16 % of cases. The coefficient of relaxation of the masticatory muscles made it possible to obtain a true state of 24 %, a false one – in 8 %. We concluded that the compression ratio is less suitable for separating patients with and without dysfunction of the temporomandibular joint.

Stomathognatic system function in indigenous people from Brazilian Xingu villages: An electromyographic analysis.

The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student’s t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.

Electromyographic analysis of stomatognathic muscles in elderly after hippotherapy.

The aging process affects the entire human body, including the stomatognathic system, and can trigger not only occlusal but also postural imbalances involving other muscular chains. Hippotherapy has been used to promote cervical, postural, and balance control in individuals with diverse impairments. The present study used electromyography to evaluate the masseter and temporal muscles in an elderly population pre- and post-hippotherapy. Participants included 17 individuals, mean age 66,5±7 years. Electromyographic recording of the bilateral masseter and temporal muscles was performed during the postural resting condition and activities that involved the active participation of these muscles in different conditions. The practitioner performed no other type of activity or exercise during the intervention because the objective is to evaluate the effect of the three-dimensional movement provided by the horse. Raw electromyographic data were tabulated using commercially available software (IBM® SPSS® Statistics 234.0) and subjected to statistical analysis, in which p ≤ 0.05 was considered to be statistically significant. Post-hippotherapy, there was lower electromyographic activity for the masseter and temporalis muscles in all the static mandibular tasks, with significant effect for time for the right temporal muscle (p = 0.038), the left temporal muscle (p = 0.028) and in the all dynamic mandibular tasks for the left temporal muscle (p = 0.025) and the left masseter muscle (p = 0.027). Hippotherapy promotes a reduction in the myoelectric activity of the masticatory muscles of elderly individuals.