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Objective: Introduction: The main causes of dysfunctional conditions of the temporomandibular joints (TMJ), are occlusal, neurogenic, orthodontic disorders. The muscular component of TMJ is determines the dynamic anatomical and functional state of the mandible Therefore, in the diagnosis of dysfunctions and understanding of their pathogenesis belongs to the electromyographic method of investigation. The aim of the work was a comparative assessment of the bioelectrical activity of the actual chewing and temporal muscles in patients with musculo-articular compressiondislocation dysfunction of the TMJ of various severity., Patients and Methods: Materials and methods: Electromyographic studies of temporal and masticatory muscles were performed in 43 patients. Was assess maximal parameters were recorded with the greatest compression of teeth and in the periods of chewing on the side of the pain symptom and on the opposite side (μV), the frequency of filling the myogram (Hz), the time of activity (Ta) and the resting time (Tc), coefficient "K", which determines the ratio of the processes of activity and rest with functional samples (K = Ta / Tc)., Results: Results and conclusions: The main feature of the functional properties of the studied muscles in the compression-dislocation dysfunction of the TMJ is the prevalence of the maximum indices of their bioelectrical activity on the side of the joint with the dislocation of the articular head of the mandible in comparison with the joint, which is in a compression state both during periods of compression of the teeth and mastication. This kind of discoordination in the work of the muscular masticatory apparatus is reflected in the severity of the course of dysfunction.

Background: Temporomandibular joint dysfunction is often related to excessive load in the stomatognathic system., Objectives: The objective of the model tests, using numeric calculations, was to assess the articular disc loads in the temporomandibular joints after prosthetic and pharmacological treatment of functional disorders of the masticatory organ., Material and Methods: The study involved 10 patients, aged 21-48 years, of both sexes, randomly selected from a group of 120 patients treated with relaxation occlusal splints (60 patients, group I) and intramuscular injection of botulinum toxin type A (60 patients, group II), suffering from temporomandibular joint dysfunction with the dominant muscle component. In all subjects, a specialized functional examination was carried out. Treatment groups: occlusal splint therapy (group I) and intramuscular injection of botulinum toxin type A (group II). An assessment of the loads of 4 disc zones of the temporomandibular joints was carried out based on the results of clinical studies (phase I of the study), and numeric model tests (phase II). In the representatives of the study groups (5 patients in each group), measurements of occlusal forces and an evaluation of tension of the masseter and temporalis muscle were performed., Results: The results of the average load values for all evaluated zones of the right and left articular disc differ in a statistically significant way in favor of group II, with the exception of the external mid part of the discs. In the case of the anterior of the right disc, the load was lower in patients belonging to group I than in those obtained in group II., Conclusions: Botulinum toxin type A significantly reduces the loads within the temporomandibular joints, generated by masseter muscle hypertonia.

The present study examined if unilateral pain from temporomandibular disorders (TMD) was associated with the occlusion contacts and surface electromyographic (SEMG) activities of jaw-closing muscles. Eleven patients with unilateral TMD pain and 20 healthy volunteers who all had Angle's Class-I occlusions were enrolled. The numbers and load distributions of the occlusion contacts and the SEMG activities of the anterior temporalis (TA) muscles and masseters muscles (MM) during maximal voluntary clenching (MVC) in the centric and eccentric positions were simultaneously recorded on both sides. The pain was not associated with occlusal contact numbers or load distributions. The SEMG activities of the pain-side TA and bilateral MM were lower during centric MVC compared with controls. The SEMG activities of the non-pain-side TA and the normalized SEMG activities of the bilateral TAs and MMs were higher during protrusive MVC (p<0.05). During pain-side MVC, the normalized SEMG activities of the working-side MM and balancing-side TA were higher than those of the controls. In conclusion, the TMD pain side was not associated with the occlusal contacts, but the patients with TMD had TA and MM SEMG activities during different tasks that differed from controls and that did not seem related to the pain side., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objective: The aim of this study was to detect sonographic predictors for the efficacy of massage treatment of masseter and temporal muscle in temporomandibular disorders (TMDs) patients with myofascial pain., Methods: Thirty-seven TMD patients with myofascial pain (6 men and 31 women, a median age of 45 years) were enrolled. An oral rehabilitation robot massaged the patient's masseter and temporal muscles with a standard massage pressure of 10 N for 16 min. The standard treatment protocol was set five sessions every 2 weeks. The median total duration of treatment was 9.5 weeks. Efficacy of treatment was evaluated based on maximum mouth opening and visual analog scale scores of muscle pain and daily life impediments. The intramuscular echogenic bands and elasticity index ratios of the masseter muscles were evaluated on sonographic or sonoelastographic images obtained before treatment and after the third and last treatment sessions., Results: The sonographic features detected different changes after the third treatment session between the therapy-effective and therapy-ineffective groups: in the therapy-effective group, the frequency of visibility of the distinct echogenic bands increased, and the elasticity index ratio decreased., Conclusion: Sonographic features after the third treatment session may be useful as predictors of therapeutic efficacy.

Aims: To investigate the effects of the application of an acute alteration of the occlusion (ie, interference) on the habitual masseter electromyographic (EMG) activity of females with temporomandibular disorders (TMD)-related muscular pain during wakefulness., Methods: Seven female volunteers with masticatory myofascial pain participated in a crossover randomized clinical trial. Gold foils were glued on an occlusal contact area (active occlusal interference, AI) or on the vestibular surface of the same molar (dummy interference, DI) and left for 8 days. The masseter electromyogram was recorded during wakefulness in the natural environment by portable recorders under interference-free, dummy-interference, and active-interference conditions. The number, amplitude, and duration of EMG signal fractions with amplitudes above 10% of the maximum voluntary contraction (activity periods, APs) were computed in all experimental conditions. Muscle pain, headache, and perceived stress were each assessed with a visual analog scale (VAS), and an algometer was used to assess masseter and temporalis pressure pain thresholds. Data were analyzed by means of analysis of variance., Results: The frequency and duration of the recorded APs did not differ significantly between the experimental conditions (P>.05), but a small and significant reduction of the EMG mean amplitude of the APs occurred with AI (P<.05). Neither the VAS scores for muscular pain, headache, and perceived stress nor the pressure pain thresholds changed significantly throughout the entire experiment (P>.05)., Conclusion: An active occlusal interference in female volunteers with masticatory muscle pain had little influence on the masseter EMG activity pattern during wakefulness and did not affect the pressure tenderness of the masseter and temporalis.

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

Aims: To compare the masticatory and cervical muscle tenderness and pain sensitivity in the hand (remote region) between patients with temporomandibular disorders (TMD) and healthy controls., Methods: Twenty female subjects were diagnosed with chronic TMD, and 20 were considered healthy. Subjects completed the Neck Disability Index and Limitations of Daily Functions in a TMD questionnaire. Tenderness of the masticatory and cervical muscles and pain sensitivity in the hand were measured using an algometer. Three-way mixed analysis of variance (ANOVA) evaluated differences in muscle tenderness between groups. One-way ANOVA compared pain sensitivity in the hand between groups. Effect sizes were assessed using Cohen guidelines., Results: Significantly increased masticatory and cervical muscle tenderness and pain sensitivity in the hand were found in subjects with TMD when compared with healthy subjects. Moderate to high effect sizes showed the clinical relevance of the findings., Conclusion: The results of this study have highlighted the importance of assessing TMD patients not only in the craniofacial region but also in the neck and other parts of the body. Future studies should focus on testing the effectiveness of treatments addressing the neck and the pain sensitivity in the hand in patients with TMD.

Unlabelled: There is disagreement about the association between missing teeth and the presence of temporomandibular disorder (TMD)., Aim: To investigate whether, the span of edentulousness, gender, number of quadrants involved, pathological migration and the type of kennedy's classification are related to the temporomandibular joint (TMJ) dysfunction signs., Materials and Methods: Clinical examination of 250 patients (males 99 and females 151) was done among the age group of 35 to 45 years. The patients were partially edentulous for 6 months or more and did not wear any kind of prosthesis., Results: Among 250 subjects, females showed more TMJ dysfunction signs. Clicking sounds were present in 46.5%, mandibular deviation was present in 40% of individuals, TMJ tenderness was observed in 32% and masseter was involved in 32% of individual. Temporomandibular joint dysfunction signs in relation to pathologic migration of teeth show that clicking and mandibular deviation was present in 54.5 and 49.2% and among muscles masseter muscle tenderness 41.9% was more commonly present. Masseter muscle tenderness 64.1% was seen in individuals who were edentulous for more than 5 years., Conclusion: Females subjects had a significantly higher prevalence of TMJ dysfunction signs then male subjects. As the span and time of edentulousness, the number of missing teeth and the number of quadrant involved increased, the signs of dysfunction became more prevalent. Among the TMJ dysfunction signs deviation and clicking sound were most frequently observed. The masseter muscle was most commonly affected and demonstrated muscle tenderness.

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.

Introduction: Myofascial pain dysfunction syndrome (MPDS) is a disorder which is characterized by facial pain and limited mandibular function because of the complex nature of this disease. Malocclusion was never evaluated in MPDS patients to know its role. Electromyographic silent period durations of masseter were used for objective assessment of MPDS patients., Aim: To evaluation of role of malocclusion in MPDS patients and also to study the EMG masseteric silent period pattern in MPDS patients in different malocclusions., Materials and Methods: Two groups, groups I and II of 75 subjects each, were included in this study. Groups I and II constituted the normal subjects and MPDS patients respectively. All these subjects in both the groups were again subdivided based on Angle's class I, II and III malocclusion. Electromyographic (EMG) silent period of masseteric muscle on both sides was measured for all the subjects in both the groups to know whether it differs according to the type of malocclusion., Results: The silent period was more in group II (MPDS patients). There was no signifcant difference in the silent periods in Angle's class I, II and III malocclusion in group I, whereas in group II, there was a signifcant difference in the silent period in Angle's class II compared to Angle's class I and III. There was no signifcant difference between males and females., Conclusion: MPDS patients are more in Angle's class I malocclusion. Silent period is more in Angle's class II malocclusion of MPDS group. CLINICAL SIGNIFCANCE: The EMG masseter silent period duration can be advantageously utilized as an adjunct to clinical examination for diagnosis of myofascial pain dysfunction syndrome. It is enough if one side masseter muscle is measured for silent period duration.

There are limited studies about the effects of occlusal appliance (OA) after three months of use. This study aimed to compare myofascial pain (MP) according to RDC/TMD, craniocervical relationships (CR) and masseter and temporalis bilateral electromyographic (EMG) activity, before and after three months of occlusal appliance use. Nineteen patients participated in this study. Cephalometric and RDC/TMD diagnostics were performed previously (baseline) and at the end of the study period (three months). EMG recordings at clinical mandibular rest position (MRP), during swallowing of saliva (SW) and during maximum voluntary clenching (MVC) were performed as follows: after one hour of use of an OA; after three months of using the OA for a minimum of 16 hours each day; and immediately after removal from the mouth. MP was relieved in all patients at the end of the study period. CR did not change significantly between baseline and after removal of the OA at the end of the study period. EMG activity during MRP, SW, and MVC decreased in both muscles after one hour using the OA and maintained the same level for the three-month period. When comparing baseline versus final EMG activity without OA, a significant decrease was only observed in the masseter muscle. The results observed in the present study are relevant to clinicians because they imply that the therapeutic effect of OA does not significantly affect the homeostasis of the craniocervical system.

This study aimed to evaluate the efficacy of piroxicam associated with low-level laser therapy compared with single therapies in 32 patients presenting temporomandibular joint arthralgia in a random and double-blind research design. The sample, divided into laser + piroxicam, laser + placebo piroxicam and placebo laser + piroxicam groups, was submitted to the treatment with infrared laser (830 nm, 100 mW, 28 s, 100 J cm(-2) ) at 10 temporomandibular joint and muscle points on each side during four sessions concomitant to take one capsule a day of piroxicam 20 mg during 10 days. The treatment was evaluated throughout four sessions and 30 days follow-up through visual analogue scale (VAS), maximum mouth opening and joint and muscle (temporal and masseter) pain on palpation. The results showed that all the study groups had a significant improvement in the VAS scores (P < 0·05), and there were no significant group differences. Piroxicam was effective in the reduction of joint and muscle pain on palpation (P < 0·05) and showed the lowest temporal pain (P = 0·02) at the 30-day follow-up. The combination of low-level laser therapy and piroxicam was not more effective than single therapies in the treatment of temporomandibular joint arthralgia. The use of piroxicam was more effective in the following 30 days., (© 2012 Blackwell Publishing Ltd.)

Myofascial trigger point pain is an extremely prevalent cause of persistent pain disorders in all parts of the body, not just the head, neck, and face. Features include deep aching pain in any structure, referred from focally tender points in taut bands of skeletal muscle (the trigger points). Diagnosis depends on accurate palpation with 2-4 kg/cm2 of pressure for 10 to 20 seconds over the suspected trigger point to allow the referred pain pattern to develop. In the head and neck region, cervical muscle trigger points (key trigger points) often incite and perpetuate trigger points (satellite trigger points) and referred pain from masticatory muscles. Management requires identification and control of as many perpetuating factors as possible (posture, body mechanics, psychological stress or depression, poor sleep or nutrition). Trigger point therapies such as spray and stretch or trigger point injections are best used as adjunctive therapy.

The overall goal of this thesis was to broaden knowledge of pain mechanisms in myofascial temporomandibular disorders (M-TMD). The specific aims were to: Develop a quality assessment tool for experimental bruxism studies (study I). Investigate proprioceptive allodynia after experimental tooth clenching exercises (study II). Evaluate the release of serotonin (5-HT), glutamate, pyruvate, and lactate in healthy subjects (study III) and in patients with M-TMD (study IV), after experimental tooth clenching exercises. In (I), tool development comprised 5 steps: (i) preliminary decisions, (ii) item generation, (iii) face-validity assessment, (iv) reliability and discriminative validity testing, and (v) instrument refinement. After preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was generated. Eleven experts were invited to participate on the Delphi panel, of which 10 agreed. After four Delphi rounds, 8 items remained and were included in the Quality Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS). Inter-observer reliability was acceptable (k = 0.77), and discriminative validity high (phi coefficient 0.79; P < 0.01). During refinement, 1 item was removed; the final tool comprised 7 items. In (II), 16 healthy females participated in three 60-min sessions, each with 24- and 48-h follow-ups. Participants were randomly assigned to a repetitive experimental tooth clenching task with a clenching level of 10%, 20%, or 40% of maximal voluntary clenching force (MVCF). Pain intensity, fatigue, perceived intensity of vibration (PIV), perceived discomfort (PD), and pressure pain threshold (PPT) were measured throughout. A significant increase in pain intensity and fatigue but not in PD was observed over time. A significant increase in PIV was only observed at 40 min, and PPT decreased significantly over time at 50 and 60 min compared to baseline. In (III), 30 healthy subjects (16 females, and 14 males) participated in two sessions at a minimum interval of 1 wk. Microdialysis was done to collect 5-HT, glutamate, pyruvate, and lactate and to measure masseter muscle blood flow. Two hours after the start of microdialysis, participants were randomized to a 20-min repetitive experimental tooth clenching task (50% of MVCF) or a control session (no clenching). Pain intensity was measured throughout the experiment. Substance levels and blood flow were unaltered at all time points between sessions, and between genders in each session. Pain intensity was significantly higher after clenching in the clenching session compared to the same time point in the control session. In (IV), 15 patients with M-TMD and 15 healthy controls participated in one session and the methodology described above was used. M-TMD patients had significantly higher levels of 5-HT and significantly lower blood flows than healthy controls. No significant differences for any substance at any time point were observed between groups. Time and group had significant main effects on pain intensity. Qu-ATEBS, the 7-item evidence-based quality assessment tool, is reliable, exhibits face-validity, and has excellent discriminative validity. Tooth clenching was associated with pain, fatigue, and short-lasting mechanical hyperalgesia, but not with proprioceptive allodynia. It seems that tooth clenching is not directly related to delayed onset muscle soreness. In healthy subjects and in patients with M-TMD, levels of 5-HT, glutamate, pyruvate, and lactate were unaltered after tooth clenching. But 5-HT levels were significantly higher and blood flows significantly lower in M-TMD patients than in healthy controls at all time points. These two factors may facilitate the release, and enhance the effects, of other algesic substances that may cause pain.

Increased resting electromyographic activity (EMG), reduced EMG during maximum voluntary clenching, and a shift to lower frequencies of the mean/median power frequency (MPF) of the EMG power spectrum have been reported for patients with temporomandibular disorder pain. It is unclear, however, whether these electrophysiological phenomena can be correlated with symptom improvement during the follow-up of myofascial pain patients in treatment. The objective of this study was to monitor the therapeutic effects of two different splint concepts (standard method and a complex splint procedure assisted by transcutaneous electrical nerve stimulation, TENS) for a period of 12 weeks, by use of clinical outcome criteria and EMG recordings. We tested the hypotheses that both measures evaluated will change in parallel during treatment and that the different splint concepts will result in no outcome differences between the variables studied. For two randomly selected groups, each containing 20 non-chronic myofascial pain patients, the clinical course after splint insertion was documented over a period of 12 weeks on the basis of pain and pain on palpation ratings, in parallel with EMG recording. Baseline values were monitored for matched healthy subjects. Although there was no correlation between the course of symptom improvement and significant changes in EMG data, MPF differed significantly (p < 0.05) between healthy subjects and patients. The therapeutic effects of splints of different clinical complexity differed significantly (p < 0.05) between the patient groups, in favor of the complex oral appliances, and substantial (p < 0.001) but temporary pain relief was achieved by additional TENS. For non-chronic myofascial TMD pain patients treated with splints, the course of symptom improvement is not paralleled by significant changes in EMG data. MPF can, however, be used to distinguish between healthy subjects and patients. Splints of different clinical complexity differ in their therapeutic effects in non-chronic myofascial TMD patients, and substantial temporarily limited pain relief can be achieved by additional muscle stimulation by TENS.

Objectives: The aim of the study was to identify and correlate myofascial trigger points (MTPs) in the masticatory muscles, using thermography and algometry., Methods: 26 female volunteers were recruited. The surface facial area over the masseter and anterior temporalis muscles was divided into 15 subareas on each side (n=780). This investigation consisted of three steps. The first step involved thermographic facial examination, using lateral views. The second step involved the pressure pain threshold (PPT), marking the MTP pattern areas for referred pain (n=131) and local pain (n=282) with a coloured pencil, and a photograph of the lateral face with the head in the same position as the infrared imaging. The last step was the fusion of these two images, using dedicated software (Reporter® 8.5-SP3 Professional Edition and QuickReport® 1.2, FLIR Systems, Wilsonville, OR); and the calculation of the temperature of each point., Results: PPT levels measured at the points of referred pain in MTPs (1.28±0.45 kgf) were significantly lower than the points of local pain in MTPs (1.73±0.59 kgf; p<0.05). Infrared imaging indicated differences between referred and local pain in MTPs of 0.5 °C (p<0.05). Analysis of the correlation between the PPT and infrared imaging was done using the Spearman non-parametric method, in which the correlations were positive and moderate (0.4≤r<0.7). The sensitivity and specificity in MTPs were 62.5% and 71.3%, respectively, for referred pain, and 43.6% and 60.6%, respectively, for local pain., Conclusion: Infrared imaging measurements can provide a useful, non-invasive and non-ionizing examination for diagnosis of MTPs in masticatory muscles.

Background: Many dentists believe that sleep bruxism (SB) is a pathogenic factor in myofascial temporomandibular disorder (TMD), but almost all supportive data rely on patients' self-reports rather than on direct observation., Methods: The authors administered a structured self-report interview to determine whether a large and well-characterized sample of patients with myofascial TMD (124 women) experienced SB more often than did matched control participants (46 women). The authors then used data from a two-night laboratory-based polysomnographic (PSG) study to determine whether the case participants exhibited more SB than the control participants., Results: The results of independent sample t tests and χ(2) analyses showed that, although self-reported rates of SB were significantly higher in case participants (55.3 percent) than in control participants (15.2 percent), PSG-based measures showed much lower and statistically similar rates of SB in the two groups (9.7 percent and 10.9 percent, respectively). Grinding noises were common in both case participants (59.7 percent) and control participants (78.3 percent)., Conclusions: Most case participants did not exhibit SB, and the common belief that SB is a sufficient explanation for myofascial TMD should be abandoned., Clinical Implications: Although other reasons to consider treating SB may exist, misplaced concern about SB's sustaining or exacerbating a chronic myofascial TMD condition should not be used to justify SB treatment.

The purpose of this study was to determine if a statistically significant reduction in muscle activity (p<0.05) occurs when prolonged disclusion time (>0.4 sec/excursion) is shortened to <0.4 sec/excursion with the Immediate Complete Anterior Guidance Development (ICAGD) enameloplasty. Forty-five symptomatic, fully informed subjects (29 female, 16 male) had their right and left disclusion times recorded with T-Scan III, while simultaneously, the bilateral masseter and anterior temporalis muscle activity was recorded electromyographically with BioEMG III (n=180 muscles). This recording was done twice, once pretreatment and again posttreatment (same day) after undergoing the ICAGD enameloplasty on the same day without changing electrodes. The Student's paired t-test was utilized to detect any significant change in the muscle activity levels between the pre- and posttreatment lateral excursive muscle contractions. Highly significant reductions were found in all four muscles' activities after shortening the pretreatment prolonged disclusion time to less than 0.4 seconds (p<0.0014); after Bonferroni correction (p<0.006). When properly performed, such that the posttreatment disclusion time is <0.4 sec/excursion, the ICAGD enameloplasty predictably reduces excursive muscle activity levels in the bilateral anterior temporalis and masseter muscles. Excursive muscle hyperactivity can be a source of lactic acid accumulation, muscular ischemia, and chronic myalgic temporomandibular joint dysfunction (TMD) symptoms. The ICAGD enameloplasty significantly reduces excursive muscle contractions after completion of the first ICAGD treatment session.

Aim: Dysfunctional syndrome of the temporomandibular joint through the complexity and variability of the symptoms may result in significant structural and functional changes leading from discomfort to disability and a negative impact on quality of life., Materials and Methods: A prospective study was conducted between October 2009-December 2010, in 52 subjects diagnosed with rheumatoid arthritis and complaining of symptoms in the temporomandibular joint. The functional examination of the joint and muscle has included the assessment of the active range of motion, passive range of motion, resistance range of motions of the temporomandibular joint, dermatomes and the pain in the region of masseter, temporalis, median and lateral pterigoids, digastric, sternocleidomastoid and longus colli muscles. The ultrasound examination has included clinical aspects of alignment, shape, dynamics of the mandibular condyle, of the temporal fossa, aspects regarding the temporal and masseter muscles at rest and at contraction phases., Results: The clinical examination highlighted the presence of pain at temporomandibular jointlevel for all tested pacients. The majority complained the pain from moderate to severe level. For the majorityof cases (59,60%) the pain stars spontaneously, during the day time (80,80%) and the night time (50,60%). Over 50% from the research cases complained cracks at the temporomandibular joint level released by a movement. At the oral and dental examination of the research group 55,8% from the tested pacients presented dental cavities toothless partially or totally duet o additionally overworking temporomandibular joint. The limitation of the range of motion is not the most important detected dysfunction, affecting approximately 30% of the cases that have been studied. Pain and spasm in a very large proportion are present in the masseter and temporal muscles regions. Atrophy is present in a lesser extent. The dysfunctional index shows an involvement of the temporomandibular joint, for over 45% of patients tested. The ultrasound examination revealed degenerative inflammatory lesions at a rate of 38.46%, inflammatory lesions at a rate of 28.85% and mixed lesions at a rate of 9.62%., Conclusions: The research regarding the clinical paraclinical and functional aspects of temporomandibular joint, permited to highlight the fact that rheumatic inflamatory and degenerative, pathology, characterises it self through a high index of morbidity and disability that lowers the life quality. Establishing a treatment plan involves customizing all clinical, functional and laboratory data.

A randomized controlled trial was performed to compare the short-term effectiveness of botulinum toxin injections and physiatric treatment provided by means of Fascial Manipulation techniques in the management of myofascial pain of jaw muscles. Thirty patients with a Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) diagnosis of myofascial pain were randomized to receive either single-session botulinum toxin injections (Group A) or multiple-session Fascial Manipulation (Group B). Maximum pain levels (VAS ratings) and jaw range of motion in millimeters (maximum mouth opening, protrusion, right and left laterotrusion) were assessed at baseline, at the end of treatment, and at a three-month follow-up. Both treatment protocols provided significant improvement over time for pain symptoms. The two treatments seem to be almost equally effective, Fascial Manipulation being slightly superior to reduce subjective pain perception, and botulinum toxin injections being slightly superior to increase jaw range of motion. Differences between the two treatment protocols as to changes in the outcome parameters at the three-months follow-up were not relevant clinically. Findings from the present investigation are in line with literature data supporting the effectiveness of a wide spectrum of conservative treatment approaches to myofascial pain of the jaw muscles. Future studies on larger samples over a longer follow-up span are needed on the way to identify tailored treatment strategies.

Management of myofascial pain focuses on two goals: reducing pain and improving function in the muscles of mastication. A multidisciplinary treatment approach is typically used to help achieve these goals. The following case series report explores the impact of oral motor exercises on the management of myofascial pain when used in conjunction with other treatment modalities. Oral motor exercises are used by speech-language pathologists to improve the strength, range of movement and coordination of the oral musculature during non-speech movements. The findings of this case series report suggest an opportunity exists for collaboration between speech-language pathologists and the "traditional" TMD team.

Simulation in 3D-model of skeletal forms of sagittal malocclusion revealed tendency in tonus' modification of muscles of mastication in formation of distal and mesial occlusion. It's shown that distal occlusion is characterized by hypotonic condition of muscles of mastication, except posterior fibers of temporal muscle. Mesial occlusion is characterized by complex combination of muscle tone with prevalence of hypotonic condition of anterior fibers of temporal muscle, superficial portion of masseter muscle and medial pterygoid muscle. We have detected that using of myofunctional devices in treatment of sagittal malocclusion, temporomandibular joint dysfunction promotes of tone increasing of muscles of mastication.

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 MPS and malocclusion were treated using a fixed orthodontic treatment. They showed improvement, although no resolution, in the signs and symptoms of MPS, compared with the untreated control group.

The present study was designed to compare the effects of low-level laser with occlusal splints in patients with signs and symptoms of myofascial pain (MP) dysfunction syndrome. A total of 40 (34 women and 6 men, with a mean age of 32.84 [SD, 10.70] years) were selected after the diagnosis of MP according to the Research Diagnostic Criteria for Temporomandibular Disorder. The patients were randomly divided into 2 groups: study group (n = 20) and control group (n = 20). Low-level laser was applied to patients in the study group 2 times per week, for a total of 10 sessions. Patients in the control group were instructed to wear occlusal splints 24 h/d for 3 months. The functional examination was based on Research Diagnostic Criteria for Temporomandibular Disorder and pressure pain threshold values were obtained with the aid of an algometer in both groups. Patients' self-report of pain was evaluated with visual analog scale. Comparisons were made within and between the groups before and after treatment. Vertical movements showed statistically significant improvements after the treatments in both groups (P < 0.01), but when the groups were compared with each other, there were no significant difference between the groups. In both groups, tenderness to palpation of the muscles decreased significantly. Pressure pain threshold evaluations and visual analog scale scores revealed similar results, too. This particular type of low-level laser therapy (820 nm, 3 J/cm2, 300-mW output power) is as effective as occlusal splint in pain release and mandibular movement improvement in MP.

Muscle hyperactivity is a potential source of symptomatology in patients with temporomandibular disorders. Various occlusal adjustment procedures have been advocated to reduce hyperactivity. A new, measurement-driven, occlusal adjustment procedure, known as immediate complete anterior guidance development (ICAGD), has been shown through nonsimultaneous electromyography to lessen masticatory muscle hyperactivity effectively by reducing posterior disclusion time to <0.4 sec in all mandibular excursions. This reduction, in turn, lessens the volume of periodontal ligament compressions that create additive and excessive functional muscle contractions via a feedback mechanism involving the trigeminal nerve. This case report describes the treatment of chronic muscular hyperactivity with a computer-guided ICAGD enameloplasty and simultaneously recorded electromyography. Follow-up visits showed that after reduction, the pretreatment levels of excursive muscular hyperactivity were lessened and lasting. This result is caused by the shorten ed posterior disclusio time resulting in an equally reduced time to muscle shutdown.

The aim of this study was to analyze the effect of low level laser applied to acupuncture points of patients diagnosed with temporomandibular dysfunction (TMD). Ten patients aged between 20 and 50 years were clinically examined with regard to pain and dysfunction of the masticatory system. They received laser applications (GaAlAs diode laser, 780 nm wavelength; 70 mW power output, 35 j/cm(2)) in acupuncture specific points (Ig4, C3, E6, E7) once a week, for ten sessions. The range of jaw movement was registered after each session and visual analogue scale (VAS) was applied. Results were analyzed (SPSS-15.0-Chicago) during the comparison, before and after treatment. Statistical tests showed significant improvements (p < 0.01) in painful symptoms and electromyographic activities of masseter muscles in maximal habitual occlusion after laser applications but no significant improvements (p = 0.05) in measurements of mandibular movements. The laser therapy in specific acupuncture points promoted improvement of symptoms and it may be used as complementary therapy for TMD., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Aims: To assess whether pain-related awakenings occur with persistent orofacial pain conditions and whether it is related to pain severity., Methods: Reports of pain-related awakening were prospectively collected at initial interview, prior to treatment, during a 24-month period from 328 patients with orofacial pain. The pain conditions were diagnosed according to the International Headache Society, the American Academy of Orofacial Pain,and the Research Diagnostic Criteria for Temporomandibular Disorders., Results: Pain-related awakening was significantly correlated to pain intensity (odds ratio [OR] 1.5, 95% confidence intervals [CI] 1.3-1.8; P < .001), the total muscle tenderness score (OR 1.1, 95% CI 1.01-1.14; P = .03), and the presence of lacrimation (OR 4.6, 95% CI 1.7-12.3; P = .002) but not to the clinical diagnosis. Two groups of patients were specifically examined; patients with masticatory myofascial pain (MMP) and patients with classical trigeminal neuralgia (CTN). Twenty-eight of the 120 MMP patients (23.3%) reported pain-related awakening and this was associated with a high muscle tenderness score (OR 1.13, 95% CI 1.01-1.3; P = .02) and unilaterality of pain (OR 3.9, 95% CI 1.2-12.3; P = .02). Seven of the 31 patients with CTN (22.6%) reported pain-related awakenings. Continuous background pain was the most significant parameter associated with awakening (OR 26, 95% CI 1.1-594; P < .05)., Conclusion: Persistent orofacial pain often induced pain-related awakening and this was significantly associated with pain intensity.

Aims: To evaluate the effectiveness of acupuncture in treating symptoms associated with myofascial pain of the jaw muscles., Methods: Twenty-eight subjects over the age of 18 and diagnosed with chronic myofascial pain of the jaw muscles were randomized to receive real (n = 16) or sham (n = 12) acupuncture. Prior to treatment, each subject clenched his or her teeth for 2 minutes. Acupuncture or sham acupuncture was then administered at the Hegu large intestine 4 (LI4) acupoint for 15 minutes. Real acupuncture was given by penetrating the needle through a sticky foam pad at the acupoint. Sham acupuncture was conducted by pricking the skin, without penetration, with a shortened, blunted acupuncture needle through a foam pad placed away from the acupoint. General head and neck pain ratings were obtained before and after treatment on a numerical rating scale. A mechanical pain stimulus on the masseter muscle was given before and after treatment and rated on a visual analog scale to measure pain tolerance level. Paired t tests were performed to detect significant changes in pain levels., Results: Subjects receiving real acupuncture experienced a significant reduction in jaw pain (P = .04), jaw/face tightness (P = .04), and neck pain (P = .04), and a significant increase in pain tolerance of the masseter muscle (P = .001). Subjects were not able to determine whether they received real or sham acupuncture (P = .69). No significant pain reductions were observed in the sham acupuncture group., Conclusion: A single acupuncture session using one acupoint at Hegu large intestine 4 significantly reduced most myofascial pain endpoints when compared to sham acupuncture.

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.

Aims: To compare the short-term effectiveness of a stabilization appliance with a prefabricated occlusal appliance in myofascial pain patients in a randomized controlled trial., Methods: Sixty-five patients at 2 centers were assigned to a stabilization appliance group (S group, n = 33) or a prefabricated appliance (Relax) group (R group, n = 32). The patients had been suffering from temporomandibular disorder (TMD) pain for 3 months to 40 years. The patients were examined for symptoms and signs of temporomandibular disorders according to the Research Diagnostic Criteria for TMD and treated by a general practitioner. Treatment outcomes regarding pain, registered on a visual analog scale, and overall ratings of pain, registered on a verbal scale, were evaluated at 6- and 10-week follow-up appointments, and the data from the groups were compared statistically., Results: The main treatment outcome in the 2 groups was a positive improvement of overall symptoms without any statistically significant differences between groups at either 6 or 10 weeks. At the 6-week follow-up, 72% of all patients reported a 30% reduction of the worst pain, and 55% of the patients reported a 50% reduction of the worst pain, whereas at the 10-week follow-up, the percentages were 69% and 61%, respectively. According to the verbal scale, 85% of all patients reported themselves to be "better," "much better," or "symptom-free" at the 6-week follow-up, and 83% reported this at the 10-week follow-up., Conclusion: The effectiveness of the prefabricated occlusal appliance seemed to be the same as that of the stabilization appliance. The prefabricated appliance can therefore be recommended as a short-term therapy in adult patients with myofascial pain.

Aims: To test for an association between rhythmic masticatory muscle activity during sleep, as assessed according to polysomnographic criteria for sleep bruxism (RMMA-SB), and myofascial pain (MFP), as well as the chance of occurrence of MFP in patients with RMMA-SB., Methods: Thirty MFP patients (diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders) and 30 age- and gender-matched asymptomatic controls underwent a polysomnographic examination. Also, any self-reporting of daytime clenching (DC) was registered in 58 of these subjects., Results: Most MFP patients reported mild or moderate pain (46.67% and 43.33%, respectively), and only 3 (10%) reported severe pain. Pain duration ranged from 2 to 120 months (mean 34.67 +/- 36.96 months). Significant associations were observed between RMMA-SB and MFP as well as between DC and MFP., Conclusions: (1) RMMA-SB is significantly associated with MFP; (2) although RMMA-SB represents a risk factor for MFP, this risk is low; and (3) DC probably constitutes a stronger risk factor for MFP than RMMA-SB.

Associations of evening and morning masticatory muscle pain and nocturnal electromyography (EMG) activity with psycho-behavioural factors and occlusal splint therapy were studied during a 20-week study-protocol. Over a period of almost 2 years, only eight of the 120 eligible patients were willing to enroll the study protocol. Further, four of the eight participants dropped out during the study, and approximately 20-30% of the nocturnal EMG recordings failed. Because of the impractical and unworkable nature of the protocol, the study was prematurely terminated and the results of the four remaining individuals are reported here as single-patient clinical trials. Univariate and multiple regression analyses revealed that in three of the four patients, changes in nocturnal EMG activity were associated with the period of splint therapy. However, no associations were found between the changes in nocturnal EMG activity and the observed changes in muscle pain. In two patients, the changes in muscle pain were associated with the period of splint therapy and with the changes in psychological stress. Within the limitations of single-patient clinical trials, it can be concluded that changes in chronic masticatory muscle pain seem to be more related to changes in psychological stress than to those in parafunctional activities.

Objectives: To compare the effect of real acupuncture and sham acupuncture in the treatment of temporomandibulat joint myofascial pain, in order to establish the true efficacy of acupuncture., Methods: A double blind randomised controlled trial conducted in the TMD Clinic, at the School of Dentistry, The University of Manchester. Twenty-seven patients were assigned to one of two treatment groups. Group 1 received real acupuncture treatment whilst Group 2 received a sham acupuncture intervention. Both the assessor and the patient were blinded regarding the group allocation. Baseline assessment of the outcome variables was made prior to the first treatment session, and was repeated following the last treatment., Results: The results demonstrated that real acupuncture had a greater influence on clinical outcome measure of TMJ MP than those of sham acupuncture, and the majority of these reached a level of statistical significance., Conclusion: Acupuncture had a positive influence on the signs and symptoms of TMJ MP. In addition, this study provides evidence that the Park Sham Device was a credible acupuncture control method for trials involving facial acupoints.

Migraine is defined as a primary headache; however, some reports may suggest a relationship with dental occlusion and dental parafunction (clenching or grinding of the teeth). A patient diagnosed with migraine with aura, with concomitant temporomandibular joint and masseter muscle pain, was treated by the use of a dental appliance. The treatment succeeded in eliminating headache and visual aura, and significantly reducing the other symptoms. A headache related to dental occlusion and dental parafunctions seems to be able to mimic a primary migraine headache. Therefore, dental evaluation is always advised for headache diagnosis.

Simultaneous recording of excursive function and muscle activity on 62 MPDS patients demonstrated that reducing prolonged disclusion time (1.4 seconds per excursion) to short disclusion time (0.41 seconds per excursion) created a therapeutic effect such that within one month's time following treatment, there was an observed increase in the maximal clenching capacity of the masseter and temporalis muscles. This clinical treatment effect appears to be the result of decreased ischemia in these same muscles resultant from minimizing the time posterior teeth compress their periodontal ligament mechanoreceptors as these teeth are engaged and disengaged during excursive function.

The aim of this study was to test the hypothesis that strengthening masticatory muscles using a controlled chewing exercise protocol improves muscle function, as evaluated quantitatively by electromyogram, and reduces pain at rest and during function. The study included 20 patients diagnosed with myofascial pain according to the Research Diagnostic Criteria for Temporomandibular Disorders with low masseter volume increase during maximal clench. The exercise group (ten patients) was subjected to a controlled gum chewing exercise protocol for eight weeks: the control group (ten patients) received only support and encouragement. Patients were examined at the beginning and at the end of the experiment which included an electromyogram (EMG) to assess muscle performance, masticatory muscle tenderness to palpation, mouth opening range, subjective anamnestic indices to evaluate pain perception and pain relief, and chewing tests. The EMG showed that the masticatory muscle exercise did produce objective physiologic results. In the exercise group, a significant increase was found in the electric muscle activity of the masseters during maximal voluntary clench (p=0.007). The exercise group showed significant reduction in pain during rest, pain during the chewing test, and a disability score. At the end of the study, a difference between the two groups was shown in the Pain Relief Scale: significantly greater pain relief was found in the exercise group as compared to the control group (p=0.019). For all other clinical parameters, there was no difference between the two groups or interaction between time and treatment. The results of this study seem to be equivocal. Additional experiments on larger population groups with extended chewing protocols are necessary before a more substantial conclusion can be reached.

Purpose: The aim of the present study was to access any changes in the muscle hardness of the masseter muscle between normal subjects and patients with myofascial pain during brief sustained isometric contractions at various bite force levels, and to compare muscle hardness, especially in terms of the recovery phase, after a clenching task., Materials and Methods: Ten patients with masticatory myofascial pain and 10 age- and weight-matched normal healthy controls participated in this study. First, the hardness of the right masseter muscle was measured at the bite force of 0, 3, 6, and 9 kgf with a hand-held hardness meter. Then, the subjects were requested to exert a 9 kgf-clenching task for 30 seconds. The muscle hardness was again measured at 5, 30, and 120 seconds after the task, and the data obtained were compared with the muscle hardness before the clenching task., Results: The results showed that there was no significant difference between the patients and the normal controls, while the muscle hardness increased with contraction in all subjects. The present findings also showed that the patients had a delayed return to baseline after the clenching task compared with the normal subjects, although an immediate increase after the clenching task was seen in all subjects., Conclusion: The results indicated that patients with masticatory myofascial pain have different muscle properties in the recovery phase after contraction, probably because of a slower intramuscular reperfusion.

The purpose of this study was to evaluate the effectiveness of the therapy with a centric relation stabilization appliance (CRSA) in patients with temporomandibular disorders of myogenous origin by electromyography and compare the results with two asymptomatic control groups. Three groups of 20 patients each were selected for the study. Electromyography (EMG) of masseter and anterior temporalis muscles was performed during mandibular rest position. In the treated group, the occlusal appliance reduced the electrical activity of the analyzed muscles at right and left sides (p<0.0001), and equilibrated muscular activity between right and left sides (p<0.0001), reaching values close to the control groups. Although there was not a statistically significant difference, the normal control group presented lower EMG values than control group II and presented the lowest asymmetry index of all subjects. More than 85% of all subjects, including the controls, demonstrated a statistically significant temporal anterior activity prevalence (p<0.0001). Treatment with the CRSA reduced the activity index, although the prevalence of the temporal muscle over the masseter was maintained. The significant laterodeviating (torque) effect found in the temporomandibular disorder patients was reduced after treatment. No side prevalence was found in the control groups.

Aims: To prospectively evaluate the effectiveness of a treatment regimen comprising counseling and physical therapy in patients with myofascial pain of the masticatory system, and to explore whether the duration of the physical therapy offered (4 vs 6 weeks) would influence the treatment result., Methods: Twenty-six patients were randomly distributed over 2 groups. All patients received reassuring information, advice regarding relaxation of the jaws, avoiding parafunctions, and limited use of the jaws. In addition, a physical therapy program (heat application, massage, ultrasound and muscle stretching) was initiated 2 weeks after the start of the study (group I, receiving 4 weeks of physical therapy) or immediately from the start of the study (group II, receiving 6 weeks of physical therapy). The following parameters were taken at baseline, 2, 4, and 6 weeks: visual analog scale (VAS) scores of present pain; lowest and highest pain over the past period; percentage of pain relief; jaw function assessment by the Mandibular Function Impairment Questionnaire (MFIQ); and pressure pain thresholds (PPTs) of the masseter, temporalis, and thumb muscles. Statistical analysis used a linear mixed model and corrected for multiple testing (Tukey test)., Results: Pain and MFIQ scores decreased while PPTs increased in both groups. Only after 4 and 6 weeks, significant differences were present for the PPT of the masseter in group I (P < .02) and the temporalis in both groups (P < .01). Also, the VAS scores of present (P < .02), minimal (P < .01), and maximal (P < .0001) pain and the MFIQ score (P < .001) improved. After 6 weeks, a mean of 60% pain decrease was reported (P < .0001). There were no significant differences between the groups receiving 4 weeks vs 6 weeks of physical therapy., Conclusion: A conservative approach involving counseling and physical therapy resulted in significant improvement in parameters of pain and jaw function in patients with myofascial pain. A controlled study will be necessary to elucidate the specific effectiveness of physical therapy over counseling or no treatment.

Neither the etiology of muscle-related temporomandibular disorders (TMD) nor the reason for the disproportionate number of women suffering from these disorders is well-established. We tested the hypothesis that physiologically relevant exercise (i.e., chewing bubble gum for 6 min) increases masticatory muscle pain in patients, but not in asymptomatic control subjects, and that female patients experience a significantly greater increase than males. Chewing increased pain in both female and male patients and, unexpectedly, also in female control subjects. One hour after chewing, the pain remained above pre-test levels for female patients but not for the other groups. Thus, sex differences in chewing-induced pain were found in control subjects but not as hypothesized in patients. Because chewing-induced masticatory muscle pain was significantly greater in female control subjects than in males, and persisted longer in female patients than in males, these results suggest greater susceptibility in women.

Surface electromyography (EMG) allows the quantification of the occlusal equilibrium in dysfunctional patients, for instance in those with temporomandibular disorders (TMD). Fourteen patients (ten women, four men) with internal derangement type I were selected among the TMD patients referred to a private practice in Milan. A stabilization splint with posterior contacts was made for each patient. To verify the static neuromuscular equilibrium of occlusion, EMG activity of left and right temporal and masseter muscles was recorded in all patients and the activity (ratio between the activities of the temporal and masseter muscles) index was computed over a maximum voluntary clench test of 3 s. Muscular waveforms were also analysed by computing a percentage overlapping coefficient (POC, an index of the symmetric distribution of the muscular activity determined by the occlusion). The total electrical activity was measured by calculating the area under the entire muscular waveforms. In all patients EMG was performed just before and immediately after the insertion of the splint and data were compared by paired Student's t-tests. Overall, the splint reduced the electrical activity of the analysed muscles (P < 0.005) and made it more equilibrated both between the left and right side (larger symmetry in the masseter muscle POC, P < 0.05) and between the temporal and masseter muscles (activity index, P < 0.01).

The objective of this study was to compare the exteroceptive suppression patterns of masseter and temporalis muscles in patients with primary and secondary headache disorders originating from peripheral joint dysfunction. We accomplished the temporalis and masseter exteroceptive suppression in 28 patients with migraine, 25 patients with chronic tension-type headache (CTH), 22 patients with temporomandibular joint (TMJ) dysfunction and 18 healthy controls. The onset latencies and duration of the first suppression period (S1) was not significantly different between the patients and controls. The duration of the second suppression period (S2) was shorter in patients with CTH, migraine (analysed during attack) and TMJ dysfunction than those obtained from controls. A distinctive finding was significantly prolonged onset latency in patients with TMJ over those obtained from patients with CTH and migraine. We concluded that the onset latency of the S2 period is a useful parameter in the differential diagnosis of primary and peripheral headache disorders.

Background: Hypnorelaxation has a potentially beneficial effect in the treatment of masticatory myofascial pain disorders (MPD). However, there are no data regarding the efficacy of hypnorelaxation in the treatment of MPD compared with other accepted modes of treatment (such as occlusal appliance) or with the mere effect of time., Objective and Subjects: The purpose of the present study was to evaluate the effectiveness of hypnorelaxation in the treatment of MPD compared with the use of occlusal appliance and/or to minimal treatment. The study population consisted of 40 female patients with myofascial pain who were allocated to 1 of 3 possible treatment groups: (1) hypnorelaxation (n = 15), (2) occlusal appliance (n = 15), and (3) minimal treatment group (n = 10)., Results: Both active treatment modes (hypnorelaxation and occlusal appliance) were more effective than minimal treatment regarding alleviating muscular sensitivity to palpation. However, only hypnorelaxation (but not occlusal appliance) was significantly more effective than minimal treatment with regard to the patient's subjective report of pain on the Visual Analog Scale., Conclusion: Hypnorelaxation is an effective mode of treatment in MPD, especially with regard to some of the subjective pain parameters.

The purpose of the present study was to elucidate the effects of unilateral masseter muscle pain on the jaw-jerk reflex. The latency and peak-to-peak amplitude of bilateral electromyographic activity recorded at the masseter muscles during the jaw-jerk reflex were measured in 18 patients with craniomandibular dysfunction (CMD) with strictly unilateral masseter pain or tenderness and 10 control subjects using a computerized recording and analysis system. The reflex was elicited, at the mandibular rest position, by tapping the centre of the chin downwards with a reflex hammer incorporating a microswitch that triggered the sweep of the recording apparatus upon contact with the chin. In the CMD group, the jaw-jerk latency on the affected side (6.89 +/- 0.98 ms) was significantly shorter (P < 0.01) than that on the unaffected side (7.59 +/- 0.92 ms). In the control group, there was no difference between the jaw-jerk latencies on the right (7.06 +/- 0.64 ms) and the left (7.08 + 0.65 ms) sides. The range of side asymmetry for jaw-jerk latencies in the CMD group was greater than that in the control group. In six patients, the latency difference exceeded 1 ms. The asymmetry of latency of the jaw-jerk reflex was thought to be due to facilitation on the side with masseter pain or tenderness. This facilitation on the ipsilateral side might be produced by enhanced gamma drive induced by sustained nociceptive stimulation. Such effects may be related with clinically derived concepts regarding such muscle dysfunction as myospastic activity or trigger points.

It is well known that bite force and EMG activity are considerably reduced in edentulous patients, but the susceptibility of their jaw-closing muscles to localized fatigue is less certain. This information is even less clear for edentulous subjects who have TMD. Eleven healthy edentulous subjects and 10 edentulous subjects with TMD participated in this study. Maximum bite force was measured first, with the transducer placed on the canine-first premolar region bilaterally, and then two rapid relaxations were made from a brief voluntary clench to 50% of maximum. A sustained voluntary clench of 50% of maximum was then maintained and endurance time was noted. EMG was recorded from both masseter muscles and the median frequency of the power spectrum of the EMG from 2 s at the beginning of the sustained clench and 2 s at the end was subsequently calculated. Two more rapid relaxations from brief clenches were performed immediately after the sustained clench. The mean maximum bite force in the healthy group was 115 N (SD +/-41) and in the TMD group was 75 N (SD +/-22), this difference being significant (P = 0.0013). The mean endurance time in the healthy group was 86 s (SD +/-51) and in the TMD group was 63 s (SD +/-20). The percentage change in the median frequency in the healthy group as a result of the sustained contraction was 6% (left) and 8.6% (right) and in the TMD group was 13.9% (left) and 12.8% (right). The percentage change in the mean relaxation half time for the healthy group was 28.5% and for the TMD group was 72%, a significant difference (P = 0.0046). It was apparent that the maximum bite force was low in edentulous subjects and was further reduced in edentulous TMD subjects; endurance time was reduced in TMD subjects; fatigue resistance of the masseter muscles was reduced in TMD subjects.

This study was conducted in order to determine the input visual effect on electromyographic (EMG) activity of the sternocleidomastoid and masseter muscles in the supine and lateral decubitus positions. The study was performed on 22 patients with myogenic cranio-cervical-mandibular dysfunction (CMD) and 18 healthy subjects. EMG activity at rest and during swallowing of saliva and maximal voluntary clenching was recorded in the supine and lateral decubitus positions in the following conditions: 1. with eyes open; and 2. with eyes closed after 5 minutes in a dark room. A significant decrease of EMG activity at rest with closed eyes in both groups was observed in the sternocleidomastoid (lateral decubitus position) and in the masseter muscle (supine position). During swallowing of saliva a significant decrease of EMG activity with closed eyes was observed only in the sternocleidomastoid muscle (lateral decubitus position) in healthy subjects. During maximal voluntary clenching any significant differences were observed upon variation in the visual input. The significant change in EMG activity, mainly observed at rest, suggests that the visual input effect is weak. The absence of a significant change in EMG activity during maximal voluntary clenching upon variation in the visual input could be clinically relevant in patients with myogenic CMD who habitually brux.

The aim of this study was to compare the effects on the level of serotonin (5-HT) in the masseter muscle by intramuscular glucocorticoid (GC) administration in patients with fibromyalgia (FM) and localized myalgia (LM), as well as to determine associated changes in pain, tenderness, and microcirculation. The study comprised 22 patients with pain and tenderness in the masseter muscle region. Ten patients (all women) had FNI, and 12 (1 man and 11 women) had LM involving the temporomandibular system. The patients were examined clinically and by microdialysis at 2 visits 2-3 weeks apart and received local glucocorticoid treatment at the first visit. The ratio (S1/S2) between the initial level of 5-HT (S1) and steady state level (S2) was used as a relative measure of the intramuscular release of 5-HT. This ratio decreased significantly after treatment in the FM group. In the FM group there was also a negative correlation regarding changes between visits of 5-HT and changes of intramuscular temperature. In the LM group there was a negative correlation regarding changes between visits of 5-HT and changes of pressure pain threshold and pressure pain tolerance level. This study indicates that there is a reduction of the ratio between initial 5-HT and steady state level in the painful masseter muscle after intramuscular GC administration to FM patients, a reduction not present in the LM patients. In addition, 5-HT seems to be involved in the modulation of local muscle microcirculation in FM patients and in hyperalgesia in LM patients.

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.

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.