Nociceptive and histomorphometric evaluation of the effects of ozone therapy on the rat masseter muscle in a carrageenan model of myofascial pain.

OBJECTIVE: This study evaluated the effects of intramuscular ozone therapy on nociception, inflammation, and tissue damage caused by the injection of carrageenan in the masseter muscle of rats. DESIGN: Rat masseter muscles were injected with saline or carrageenan. Seventy-seven adult male rats were divided into six groups: Sal, saline; Car, carrageenan; Ibup + Sal, ibuprofen and saline; Ibup + Car, ibuprofen and carrageenan; O3 + Sal, ozone and saline; and O3 + Car, ozone and carrageenan. The mixture of 5% ozone and 95% oxygen (20 µg/mL) was administered three times in the course of a week. Nociceptive responses in the masseter muscles were measured using a head withdrawal threshold, determined by an electronic von Frey anesthesiometer. The animals were euthanized one or eight days after the carrageenan injection, and the masseters were submitted to histological and histomorphometric analyses. RESULTS: Mechanical allodynia and inflammation levels were reduced in the Ibup + Car group compared to the other groups. Myonecrosis was similar among carrageenan-treated groups. Picrosirius red stained sections showed more collagen fibers and more regenerating myofibers in the O3 + Car group compared to the other groups. Eight days after carrageenan injection, the O3 + Car group showed neutrophils close to the regenerating myofibers. CONCLUSIONS: Intramuscular ozone therapy did not alleviate mechanical allodynia, and it did not protect the masseter muscle against the deleterious effects produced by carrageenan, probably due to the mode of administration of this therapeutic agent.

Potential of Using Shear Wave Elastography in the Clinical Evaluation and Monitoring of Changes in Masseter Muscle Stiffness.

The study aimed to evaluate masseter muscle stiffness in adult healthy volunteers referred to a massage treatment and also to investigate whether shear-wave elastography can be used to monitor the effect of massage on the masseter muscle. The study included 21 healthy volunteers, who were subjected to a 30-minute massage of the masseter muscle. Muscle stiffness was measured by shear-wave elastography before and directly after the massage. Pain during the massage was assessed using the visual analogue scale (VAS). The data of 20 patients (one excluded due to severe pain) with a median age of 34.5 years were analysed. The stiffness values were 11.46 ± 1.55 kPa before and 8.97 ± 0.96 kPa after the massage (p < 0.0001). The mean drop was 2.49 ± 1.09 kPa. The greatest decrease was observed in people with higher elasticity values before the massage (r = 0.79; p < 0.0001). The median intensity of pain was 7.2 (range: 6-9.5). We concluded that shear-wave elastography is a sensitive tool to monitor changes in the stiffness of the masseter muscle.

Effects of mental and physical orofacial training on pressure pain sensitivity and tongue strength: A single-blind randomized controlled trial.

OBJECTIVES: The main objective of this study was to analyze differences on pain pressure thresholds, tongue strength and perceived effort between various orofacial motor exercise training dosages of mental representation training through motor imagery (MI) and action observation (AO), first in isolation and then in combination with real exercise performance. METHODS: A single-blind randomized controlled trial was designed. 48 asymptomatic individuals were randomized into two groups: Intensive training group (IG) and Moderate training group (MG). Both groups performed a first session of MI and AO of orofacial exercises training and a second session of actual orofacial exercises combined with mental representation training, but with different dosage in terms of series and repetitions. Pain pressure thresholds (PPTs) in the masseter and temporal muscles and tongue muscle strength were the main variables. RESULTS: Regarding the PPT, ANOVA revealed significant between-group differences, where MG showed a significantly higher PPT than IG at post-day2, with a medium effect size. Both groups showed with-in group differences between pre and post intervention measures in the first session, but only the IG showed differences in the second. Regarding tongue muscle strength, ANOVA revealed significant within-group differences only in MG between the pre-day and post-day first intervention. CONCLUSION: The results of the present study suggest that movement representation training performed in isolation may have a positive effect on PPTs and tongue muscle strength. In addition, the combination with the actual execution of the exercises could be considered effective, but it is necessary to take into account the training dosage to avoid fatigue responses.

Mandibular prognathism attenuates brain blood flow induced by chewing.

Mastication is closely related to brain function. Animal experiments have revealed that tooth loss has a negative influence on brain function. Clinical studies also suggest that normal occlusion is an essential factor for favorable brain function. Mandibular prognathism (MP) usually results in occlusal dysfunction. However, the relationship between MP and brain function remains unclear. In the present study, we examined the relationship between MP and brain function by measuring brain blood flow (BBF). Seventeen subjects with normal occlusion (NORM) and 25 patients with MP participated in this study. The number of occlusal contacts were counted. Electromyography of the masseter muscles during clenching was also recorded. BBF was measured with non-invasive functional near-infrared spectroscopy during calculation task and chewing task. The number of the occlusal contacts and masseter muscle activity were lower in MP compared with NORM. The calculation task increased BBF in both groups. The chewing task also increased BBF in the inferior frontal gyrus in both groups, although the increase in MP was smaller than in NORM. We discovered that patients with MP exhibited a smaller increase in BBF at the inferior frontal gyrus during chewing as compared with NORM. As such, MP would negatively affect brain function.

Immediate and short-term effects of phototherapy on pain, muscle activity, and joint mobility in women with temporomandibular disorder: a randomized, double-blind, placebo-controlled, clinical trial.

OBJECTIVES: The aim of the present study was to evaluate the immediate and short-term effects of phototherapy on pain intensity, the pressure pain threshold (PPT), maximum vertical mandibular movement, and the electrical activity of the masseter and temporal muscles in women with temporomandibular disorder (TMD). METHODS: Sixty women were randomly allocated to four different groups and submitted to phototherapy with a combination of super-pulsed laser (905 nm), red (640 nm), and infrared (875 nm) light emitting diodes in the same equipment on the masseter (three points) and temporal (two points) muscles bilaterally in a single session. The following doses were used in each point of application: Group 1 - 2.62 J; Group 2 - 5.24 J; Group 3 - 7.86 J; placebo group. Pain intensity was determined using the visual analog scale. The PPT was analyzed using a digital algometer. Vertical mandibular movement was measured using digital calipers. Myoelectrical activity of the masseter and temporal muscles was measured using electromyography. Four evaluations were performed: pre-intervention, immediately after, 24 and 48 hours after phototherapy. OUTCOMES: A significant reduction in pain intensity during the post-treatment evaluations in comparison to the pretreatment evaluation was observed in group 1 (Median difference = 2.60 [95% CI = 1.35-3.85]) and group 2 (Median difference = 2.2 [95% CI = 0.98-3.42]) especially after 48 hours and group 3 (Median difference = 2.50 [95% CI: 0.56-4.46]) especially after 24 hours, with a moderate effect size, but no effect was found regarding the other variables. CONCLUSIONS: A single session of combined phototherapy was capable of reducing pain intensity in individuals patients with TMD. ClinicalTrials.gov (NCT02018770). Implications for Rehabilitation Phototherapy device combining two light sources (LED and laser), and different densities in the same device is a novelty in the rehabilitation market, and has proved to be a useful intervention for people with temporomandibular disorders. This mode of phototherapy is another option that assists in the rapid intervention in pain symptoms, promoting a considerable degree of comfort to the patient moments after its application.

The effect of sensory level electrical stimulation of the masseter muscle in early stroke patients with dysphagia: A randomized controlled study.

BACKGROUND: Dysphagia is a serious cause of morbidity and mortality in stroke patients. AIMS: 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. SETTINGS AND DESIGN: This study was conducted at the Physical Medicine and Rehabilitation Clinic of our hospital between 2013 and 2015. MATERIALS AND METHODS: 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. STATISTICAL ANALYSIS: The Friedman test, Wilcoxon Signed Rank test, Mann-Whitney U test, and Fisher exact test were used in this study. RESULTS: 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. CONCLUSION: SES applied to bilateral masseter muscles may provide an effective treatment for both dysphagia and cognitive function in early stroke patients.

The use of a custom-made mouthguard stabilizes the electromyographic activity of the masticatory muscles among Karate-Do athletes.

AIMS: To analyze and compare the electromyographic activity of the temporal (anterior portion) and masseter muscles among Karate-Do athletes before and after training, with and without the use of a mouthguard. METHODS: Twenty athletes (14 males and 6 females) with a mean age of 23.7 ± 7.5 years participated. They had surface electromyography recordings taken of their bilateral temporal and masseter muscles before and after training under the following conditions: no mouthguard, with a ready-made mouthguard, and with a custom-made mouthguard. Activity was examined at mandibular rest, while clenching, and at maximum voluntary contraction. The data were normalized using the mean maximum voluntary contraction. RESULTS: The right (p = 0.005) and left (p = 0.015) temporal muscles showed significantly lower electromyographic activity with a custom-made mouthguard compared with no mouthguard after training while clenching. The electromyographic activity of the temporal and masseter muscles did not show significant differences when tested at mandibular rest and while clenching before or after training with a custom-made mouthguard (p > 0.05). CONCLUSION: The use of a custom-made mouthguard preserved participants' electromyographic profiles before and after training; thus, they allow for stable muscle activity during the training of Karate-Do athletes.

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.

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Efectos de la técnica neuromiscular sobre la musculatura temporal en sujetos con disfunción ATM / No disponible

Introducción: Las disfunciones temporomandibulares (DTM) son un conjunto de síntomas y signos entre los que se encuentran alteraciones de la musculatura masticatoria. Las disfunciones de la musculatura temporal repercuten de manera importante en dichos desordenes. Objetivos: Evaluar la influencia inmediata de la técnica neuromuscular a nivel de la musculatura temporal en pacientes con disfunción temporomandibular (DTM) y observar si se producen modificaciones de aquellos elementos objeto de medición. Material y métodos: Se realizó un ensayo clínico aleatorizado sobre 10 sujetos, con Grupo Control (GC; n = 5) y Grupo Experimental (GE; n = 5). En el GE se aplicó la técnica neuromuscular (TNM) sobre la musculatura de los temporales mientras que el GC recibió una técnica placebo consistente en la simulación de equilibración funcional de la musculatura temporal utilizando el mismo tiempo que el usado en el GE con la TNM. Resultados: En el análisis intragrupal del GE se obtuvieron datos estadísticamente significativos con un aumento del umbral de dolor a la presión (UDP) del 109,48 % en el punto gatillo (PG) del masetero derecho (p = 0,043), un 41,52 % en el PG del temporal derecho (p = 0,015) y un 39,71 % en el PG temporal izquierdo (p = 0,015). En el análisis intergrupal se produjeron diferencias estadísticamente significativas en las variables UDP en el Temporal derecho (TEMPderecho) (p = 0,005) y en la variable UDPTEMPizquierdo (p= 0,008) obteniéndose un incremento en el GE. Con respecto al análisis intragrupal del GC hubo una significancia de un 70 % en la variable UDP del Masetero derecho (MASderecho) (p = 0,042), y de un 11,84 % en la variable UDPTEMPderecho (p =0,043). Conclusiones: La TNM sobre la musculatura temporal produce un aumento en el UDP de los puntos gatillos (PGs) de los músculos temporales y en el masetero derecho

No disponible

Electromyographic study of the masseter muscle after low-level laser therapy in patients undergoing extraction of retained lower third molars / Estudio electromiográfico del músculo masetero tras terapia con láser de baja intensidad en pacientes sometidos a extracción de tercer molar mandibular retenido

The surgery for extraction of the retained lower third molar is one of the most commonly performed procedures in the field of maxillofacial surgery. During this procedure, the surgical trauma can cause damage to the function of muscles involved in mandibular movements, such as the masseter muscle. In order to accelerate post-surgical recovery, many physiotherapy resources are employed, including laser therapy. The aim was to analyze the electrical activity of the masseter muscle treated with Low-level Laser (LLL) after surgical trauma. Assessments of masseter muscle on a sample of 60 patients were performed by surface electromyography in four instances: immediate preoperative, postoperative at 7, 14 and 21 days. The patients were divided into two groups: 1- untreated group with LLL in the postoperative; 2- group treated with LLL (810 nm; 10 J/cm2) in the immediate postoperative and at 3, 6 and 9 days after surgery. On the seventh day after surgery 23.3 % of the patients in the group receiving LLL showed recovery of their muscle activity as they presented in the immediate preoperative, versus only 3.3 % of the untreated group. On the 14th day, 73.3% of treated patients showed functional rehabilitation, versus 6.7% in the untreated group, and on the 21st, 80% versus 10% in the untreated group. On the 14th postoperative day the electrical activity of the masseter muscle treated with LLL after surgical trauma was compatible with a condition of complete functional recovery. The findings of this electromyographic study indicated that LLL proved to be an efficient physiotherapeutic method for stimulating the masseter muscle functional recovery after surgery of retained lower third molars.

La cirugía para extracción del tercer molar mandibular retenido es uno de los procedimientos más realizados en el campo de la cirugía maxilofacial. Durante este procedimiento, el trauma quirúrgico puede causar daño a la función de los músculos involucrados en los movimientos mandibulares, entre ellos el músculo masetero. Con el objetivo de acelerar la recuperación postoperatoria, son utilizados muchos recursos de fisioterapia, incluyendo la terapia con láser. El objetivo de este estudio fue analizar la actividad eléctrica del músculo masetero tratado con láser de baja intensidad (LBI) después del trauma quirúrgico. Se realizaron evaluaciones del músculo masetero en una muestra de 60 pacientes, a través de electromiografía de superficie en cuatro momentos: preoperatorio inmediato, postoperatorio a los 7, 14 y 21 días. Los pacientes fueron divididos en dos grupos: 1 - grupo no tratado con LBI en el postoperatorio; 2 - grupo tratado con LBI (810 nm; 10 J/cm2) en el postoperatorio inmediato y a los 3, 6 y 9 días tras cirugía. Al séptimo día tras cirugía el 23,3 % de los pacientes del grupo tratado con LBI presentaron recuperación de su actividad muscular equivalente a lo presentado en el preoperatorio inmediato, frente a sólo el 3,3 % del grupo no tratado. En el día 14, el 73,3% de los pacientes tratados presentaron rehabilitación funcional, frente al 6,7% del grupo no tratado y en el vigésimo primer día, el 80% frente al 10% del grupo no tratado. En el dia 14 postoperatorio la actividad eléctrica del músculo masetero tratado con LBI después del trauma quirúrgico fue compatible con una condición de recuperación funcional completa. Los hallazgos de este estudio electromiográfico indicaron que el LBI es un eficiente método fisioterápico para estimular la recuperación funcional del músculo masetero tras cirugía de terceros molares mandibulares retenidos.

[Evaluating the effectiveness of the new mouthguard design in athletes involved in power sports]. / Otsenka effektivnosti primeneniya novoi konstruktsii zubnoi shiny u sportsmenov, zanimayushchikhsya silovymi vidami sporta.

The aim of the study was to assess the effectiveness of the new mouthguard design for functional rehabilitation of dental system in athletes involved in contact power sports. The functional state of dental system was evaluated by interferential electromyography of masticatory muscles and Doppler ultrasound examination of periodontal tissues. Before mouthguard use the asynchrony of masticatory muscles was seen which was released after the mouthguard application: electromyographic activity of the left and right masticatory muscles was balanced and the decrease in biopotentials amplitude was found out. The mouthguard also caused no functional disorders in periodontal tissues.

[Effect of biofeedback in regulation of masseter muscle myoelectric activities].

OBJECTIVE: To investigate the effect of the biofeedback in regulating the myoelectric activities of the masseter muscles. METHODS: Twenty orthodontic patients aged from 10 to 14 years with Angle Class II malocclusion, retrusive mandible, and an ANB angle > 6° were enrolled in this study. The muscular activities of the anterior temporal muscle and the masseter muscle were evaluated before, during, and after biofeedback treatment by assessing the average integrated electromyogram and temporal/masseter (T/M) ratio in the clenching status. RESULTS: The patients' myoelectric activities of the anterior temporal muscle was significantly increased after biofeedback treatment (P<0.05). The patients' T/M ratio in the clenching status was increased after the treatment (1.76 ± 1.46 before treatment, 4.71 ± 4.03 immediately after treatment, and 2.57 ± 2.07 at 1 day after treatment; t=4.86, P<0.05). CONCLUSION: Biofeedback treatment can regulate the activities of the anterior temporal and masseter muscles and increase the T/M ratio in the clenching status.

Electromyography of muscles involved in feeding premature infants / Avaliação eletromiográfica dos músculos envolvidos na alimentação de recém-nascidos prematuros

PURPOSE: To measure and compare the electrical activity of masseter, temporal, and suprahyoid muscles in premature newborn infants during breast-feeding and cup-feeding.METHODS: This cross-sectional observational study was carried out by the electromyographic assessment of 36 preterm infants, 53% of whom were male, with mean gestational age of 32 weeks and birth weight of 1,719 g, fed via oral route, by full breast-feeding and supplementation of diet, through cup with expressed breast milk, until 15 days after hospital discharge. Children with neurological disorders, genetic syndromes, oral-motor, and/or congenital malformations were excluded. The different methods of feeding and the variables gestational age at birth, corrected gestational age, chronological age, birth weight and size, head circumference, and Apgar scores at 1 and 5 minutes were analyzed and compared by appropriate statistical analysis.RESULTS: No difference was observed between breast-feeding and cup-feeding in the analysis of the temporal and masseter muscles. However, higher activity of suprahyoid musculature was observed during cup-feeding (p=0.001). The other variables were not correlated with the electrical activity of the muscles during the different feeding methods.CONCLUSION: There may be a balance between the activity of the temporal and masseter muscles during breast-feeding and cup-feeding. There was higher activity of suprahyoid musculature during cup-feeding. This can be explained by the greater range of tongue movement, as premature infants usually perform tongue protrusion to get the milk from the cup.

OBJETIVOS: Mensurar e comparar a atividade elétrica dos músculos temporal, masseter e supra-hióideos de prematuros durante o aleitamento materno e por copo.MÉTODOS: Estudo transversal observacional, realizado por meio da avaliação eletromiográfica de superfície em 36 prematuros, 53% do gênero masculino, com idade gestacional média de 32 semanas e peso médio ao nascimento de 1.719 g, em aleitamento misto, com suplementação de dieta por copo, até 15 dias após a alta hospitalar. Crianças com alterações neurológicas, síndromes genéticas, malformações craniofaciais, que utilizaram mamadeira, chupeta e/ou bico intermediário de silicone foram excluídas. A atividade elétrica dos músculos temporal, masseter e supra-hióideos foi comparada nos diferentes tipos de alimentação, entre os gêneros e entre as classificações do Apgar no 1º e 5º minuto e correlacionadas às variáveis idade gestacional ao nascimento, idade corrigida, idade cronológica, peso ao nascimento, estatura e perímetro cefálico ao nascimento.RESULTADOS: Não houve diferença entre os métodos de alimentação avaliados quanto à atividade elétrica dos músculos temporal e masseter, no entanto verificou-se maior atividade da musculatura supra-hióidea durante a alimentação por copo (p=0,001). As demais variáveis não apresentaram correlação com a atividade elétrica dos músculos estudados durante os diferentes métodos de alimentação.CONCLUSÃO: Parece haver equilíbrio entre a atividade dos músculos temporal e masseter durante a alimentação ao seio materno e por copo. A musculatura supra-hióidea apresentou-se mais ativa no copo, o pode ser justificado pela maior amplitude de movimentação da língua, já que geralmente os RNPT realizam a protrusão da língua para obter o leite no copo.

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

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.

Do sleep hygiene measures and progressive muscle relaxation influence sleep bruxism? Report of a randomised controlled trial.

The aim of this study was to assess the effects of sleep hygiene measures combined with relaxation techniques in the management of sleep bruxism (SB) in a double-blind, parallel, controlled, randomised clinical trial design. Sixteen participants (mean ± s.d. age = 39·9 ± 10·8 years) were randomly assigned to a control group (n = 8) or to the experimental treatment group (n = 8). Participants belonging to the latter group were instructed to perform sleep hygiene measures and progressive muscle relaxation techniques for a 4-week period. Two polysomnographic recordings, including bilateral masseter electromyographic activity, were made: one prior to the treatment and the other after the treatment period. The number of bruxism episodes per hour, the number of burst per hour and the bruxism time index (i.e. the percentage of total sleep time spent bruxing) were established as outcome variables. No significant differences could be observed between the outcome measures obtained before and after the 4-week period, neither for the sleep bruxism variables nor for the sleep variables. Within the limitations of this study, it was concluded that there is no effect of sleep hygiene measures together with progressive relaxation techniques on sleep bruxism or sleep over a 4-week observation period.

Thirty-year follow-up of a TMD case treated based on the neuromuscular concept.

AIM: Occlusal therapy is employed to alleviate the symptoms of a temporomandibular disorder (TMD) at times. However, the long-term effect of occlusal therapy in the masticatory system is not well understood. This case study aims to present a 30-year follow-up of a TMD case. METHODOLOGY: The patient developed TMD with intermittent closed lock of the left temporomandibular joint (TMJ). Chief complaints included trismus, pain, and noise of the left TMJ during function. The patient's occlusal disharmony was assessed with use of electronic instruments and corrected based on the neuromuscular concept. A minimum-invasive and reversible approach using adhesive occlusal restorations was used. RESULTS: The jaw movement and masticatory muscle activity assessed at the 7- and 23-year follow-ups revealed that the established occlusion was well adapted, and re-established the patient's functional occlusion system. The patient has been free from TMD symptoms with the corrected occlusion for 30 years. CONCLUSIONS: Occlusal reconstruction based on the neuromuscular concept can be stably integrated into the patient's functional occlusion system.

Myorelaxant effect of bee venom topical skin application in patients with RDC/TMD Ia and RDC/TMD Ib: a randomized, double blinded study.

The aim of the study was the evaluation of myorelaxant action of bee venom (BV) ointment compared to placebo. Parallel group, randomized double blinded trial was performed. Experimental group patients were applying BV for 14 days, locally over masseter muscles, during 3-minute massage. Placebo group patients used vaseline for massage. Muscle tension was measured twice (TON1 and TON2) in rest muscle tonus (RMT) and maximal muscle contraction (MMC) on both sides, right and left, with Easy Train Myo EMG (Schwa-medico, Version 3.1). Reduction of muscle tonus was statistically relevant in BV group and irrelevant in placebo group. VAS scale reduction was statistically relevant in both groups: BV and placebo. Physiotherapy is an effective method for myofascial pain treatment, but 0,0005% BV ointment gets better relief in muscle tension reduction and analgesic effect. This trial is registered with Clinicaltrials.gov NCT02101632.

Immediate changes in masticatory mechanosensitivity, mouth opening, and head posture after myofascial techniques in pain-free healthy participants: a randomized controlled trial.

OBJECTIVE: This study aimed to assess the immediate effects on masticatory muscle mechanosensitivity, maximal vertical mouth opening (VMO), and head posture in pain-free healthy participants after intervention with myofascial treatment in the temporalis and masseter muscles. METHODS: A randomized, double-blind study was conducted. The sample group included 48 participants (n=48), with a mean age of 21±2.47 years (18-29). Two subgroups were defined: an intervention group (n=24), who underwent a fascial induction protocol in the masseter and temporalis muscles, and a control group (n=24), who underwent a sham (placebo) intervention. The pressure pain threshold in 2 locations in the masseter (M1, M2) and temporalis (T1, T2) muscles, maximal VMO, and head posture, by means of the craniovertebral angle, were all measured. RESULTS: Significant improvements were observed in the intragroup comparison in the intervention group for the craniovertebral angle with the participant in seated (P<.001; F1,23=16.45, R2=0.41) and standing positions (P=.012, F1,23=7.49, R2=0.24) and for the pressure pain threshold in the masticatory muscles, except for M2 (P=.151; M1: P=.003; F1,23=11.34, R2=0.33; T1: P=.013, F1,23=7.25, R2=0.23; T2: P=.019, F1,23=6.41, R2=0.21). There were no intragroup differences for the VMO (P=.542). Nevertheless, no significant differences were observed in the intergroup analysis in any of the studied variables (P>.05). CONCLUSION: Myofascial induction techniques in the masseter and temporalis muscles show no significant differences in maximal VMO, in the mechanical sensitivity of the masticatory muscles, and in head posture in comparison with a placebo intervention in which the therapist's hands are placed in the temporomandibular joint region without exerting any therapeutic pressure.

Influence of different upper cervical positions on electromyography activity of the masticatory muscles.

OBJECTIVE: The aim of this study was to determine the activity of the masseter and anterior temporalis muscles in relation to different positions of the upper cervical spine during maximal voluntary isometric clenching by surface electromyography (EMG). METHODS: This was a cross-sectional study with a repeated-measures design performed using 25 asymptomatic subjects (13 female and 12 male; mean age, 31 years; SD, 8.51). The EMG activity of the masseter and anterior temporalis muscles was recorded bilaterally during maximal clenching at neutral position and during extension, flexion, ipsilateral lateral flexion, contralateral lateral flexion, and ipsilateral and contralateral rotations in maximal flexion. In addition, the upper cervical range of motion and mandibular excursions were assessed. The EMG activity data were analyzed using a 3-way analysis of variance in which the factors considered were upper cervical position, sex (male and female), and side (right and left), and the hypothesis of importance was the interaction side x position. RESULTS: The 3-way analysis of variance detected statistically significant differences between the several upper cervical positions (F = 13.724; P < .001) but found no significant differences for sex (F = 0.202; P = .658) or side (F = 0.86; P = .53) regarding EMG activity of the masseter muscle. Significant differences were likewise observed for interaction side x position for the masseter muscle (F = 12.726; P < .001). The analysis of the EMG activity of anterior temporalis muscle did not produce statistically significant differences (P > .05). CONCLUSION: This preliminary study suggests that the upper cervical movements influence the surface EMG activity of the masseter muscle. These findings support a model in which there are interaction between the craniocervical and the craniomandibular system.

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

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.