Masticatory Muscle Tenderness Research Articles

Effect of physiotherapeutic procedures on the bioelectric activity of the masseter muscle and the range of motion of the temporomandibular joints in the female population with chronic pain: a randomized controlled trial

SummaryIntroductionPhysical therapy (PT) methods applied in dentistry are increasingly discussed nowadays. Taking into account a rapidly growing number of temporomandibular disorders (TMDs) and orofacial pain patients, it is reasonable to determine which of the available physiotherapeutic (PT) methods are more effective than others, especially in terms of their possible analgesic and myorelaxant effects.ObjectiveTo assess manual and physical factors influencing pain reduction or elimination and increased muscle tension in patients with TMD; yet the influence of the applied forms of PT on the range of motion (ROM) of temporomandibular joints (TMJ).Material and methodsA randomized, parallel-group, RCT, single-blind, equi-randomized (1:1) study was conducted in DC/TMD Group Ib patients (20–45 years of age). An experimental group (G1, n = 104) and a control group without TMD (G2, n = 104) were created according to CONSORT guidelines. Diagnostic measurements were performed in both groups (mass sEMG, temporomandibular joint range of motion-ROM, pain intensity - NRS). Group G1 was randomly divided (envelope method) into 4 therapeutic groups, in which therapy was carried out for 10 days: magnetostimulation (MS), magnetoledotherapy (MLE), magnetolaserotherapy (MLA), manual therapy (MT). Each time after the therapy, ROM and NRS measurements were performed, and after the 5th and 10th day sEMG.ResultsStatistically significant differences were found in the sEMG values of the masseter muscles, TMJ ROM and the pain intensity in G1 and G2 (p < 0.00). The largest decrease in sEMG (% MVC) of the masseter muscle occurred in the subgroup in which the manual therapy (MT) procedures were applied, p < 0.000. There was no clinically significant difference in and between other subgroups. There was a distinct mandible ROM increase noted in the MT group, with minimal changes in the MLA and MLE groups and no changes in the MS group. There was a clear increase in the lateral mobility of both right and left TMJ in the MT group. There were no differences in the course of the study in the MS group, and slight increases in the MLA and MLE groups. In the case of pain measurements, the greatest decrease in pain intensity was observed in the MT subgroup.ConclusionsAccording to our results manual therapy is an effective form of treatment in patients with pain, increased masticatory muscle tension and limitation in mandible ROM. Dental physiotherapy should become an integral part of multimodal TMD patients’ treatment.

Comparative effectiveness of low-level laser therapy and transcutaneous electrical nerve stimulation in symptomatic Temporomandibular Disorders: A Randomised Control Trial.

Myofascial pain is one of the most common facial region pains, presenting itself with various signs and symptoms like tenderness of masticatory muscles and difficulty in mouth opening. Considering its multifactorial aetiology various treatment modalities are present. The aim of this study is to compare the effectiveness of transcutaneous electrical nerve stimulation (TENS)and low-level laser therapy (LLLT) for the patients of temporomandibular disorders (TMDS). The study was conducted with 20 patients diagnosed with TMDS. Group A received LLLT at 660 nm, 6 J/point, two sessions/week for 4 weeks and group B received TENS at 2-250 Hz, two sessions/week for 4 weeks. Pain Score decreased and mouth opening increased in both groups with time, however, the difference between the two groups was not statistically significant. Right and left lateral excursions showed improvement at different intervals in both groups. However, the LLLT group showed significant improvement. Clinical trial showed improvement in visual analogue scale (VAS), maximum mouth opening (MMO) and lateral excursion in the different time intervals in both the groups with LLLT showed more improvement with lateral excursions movements.

Prevalence of Clinical Signs and Symptoms of Temporomandibular Joint Disorders Registered in the EUROTMJ Database: A Prospective Study in a Portuguese Center.

Temporomandibular joint disorders (TMDs) are characterized by their multifactorial etiology and pathogenesis. A 3-year prospective study was conducted in a Portuguese TMDs department to study the prevalence of different TMDs signs and symptoms and their association with risk factors and comorbidities. Five hundred ninety-five patients were included using an online database: EUROTMJ. Most patients were female (80.50%), with a mean age of 38.20 ± 15.73 years. The main complaints were: (1) temporomandibular joint (TMJ) clicking (13.26%); (2) TMJ pain (12.49%); (3) masticatory muscle tension (12.15%). The main clinical findings were myalgia (74%), TMJ clicking (60-62%), and TMJ arthralgia (31-36%). Risk factors such as clenching (60%) and bruxism (30%) were positively associated with TMJ pain and myalgia. Orthodontic treatment (20%) and wisdom tooth removal (19%) were positively associated with TMJ clicking, while jaw trauma (6%), tracheal intubation (4%) and orthognathic surgery (1%) were positively associated with TMJ crepitus, limited mandibular range of motion, and TMJ pain, respectively. In total, 42.88% of TMDs patients had other associated chronic diseases, most of them were mental behavioral or neurodevelopmental disorders (33.76%), namely, anxiety (20%) and depression (13%). The authors also observed a positive association of mental disorders with the degree of TMJ pain and myalgia. The online database seems to be a relevant scientific instrument for healthcare providers who treat TMDs. The authors expect that the EUROTMJ database can serve as a milestone for other TMDs departments.

Real time evaluation of awake bruxism behaviors in young asymptomatic students and its impact on the masticatory muscles

Statement of problemThe relationship of awake bruxism with pain is still unclear. PurposeThe purpose of this clinical study was to evaluate awake bruxism behavior for 1 week in healthy young adults with ecological momentary assessment, assess its relationship with masticatory muscle tenderness, and the participation of endogenous analgesia. Material and methodsA total of 150 healthy participants were provided with a smartphone application that sent 10 alerts at random intervals every day. The participants were instructed to report in real time which of the following awake bruxism behaviors best represented their current condition: relaxed jaw muscles, tooth contact, tooth clenching, tooth grinding, or jaw bracing. At baseline, participants underwent recordings of the pressure pain threshold and conditioned pain modulation of the masticatory muscles. Pressure pain threshold recording was also repeated on the last day of the study. A t test was used to compare the first and the last pressure pain threshold recording after 1 week with an ecological momentary assessment evaluation. The Pearson correlation test was performed to evaluate the correlation between variables (α=.05). ResultsOverall compliance was 75.9%. The average frequency of relaxed jaw muscles was 54.5%, tooth contact 29.4%, jaw bracing 5.8%, tooth clenching 9.7%, and tooth grinding 0.6%. The average frequency of a distinct awake bruxism behavior was 45.5%. A statistically significant increase in pressure pain threshold values was found (P=.001; P=.001; P=.045 for right and left anterior temporalis and left masseter, respectively). No significant correlation was found between the frequency of awake bruxism behaviors, the pressure pain threshold, and conditioned pain modulation (P>.05). ConclusionsThe most prevalent behavior was tooth contact (29.4%). No relationship was found between awake bruxism behaviors and masticatory muscle tenderness or endogenous analgesia.

Masticatory muscle disorders and treatment from the perspective of prosthodontics

Masticatory muscle disorders (MMD) is the biggest subtype of temporomandibular disorders (TMD). Among them, local fibromyalgia and myofascial pain are localized lesions, manifested as masticatory muscle pain, which can be aggravated with jaw function. MMD is caused by a combination of multiple factors. Occlusal disharmony such as occlusal trauma, occlusal interference, and decreased vertical dimension of occlusion have the potential risk of inducing or aggravating the MMD. During prosthodontic treatment, iatrogenic occlusal interference should be avoided. Most patients with MMD can be relieved by comprehensive treatment, and occlusal therapy or prosthodontic treatment is used as an auxiliary means of diagnosis and treatment. By means of occlusal splint, occlusal adjustment and denture restoration, the goal of relieving masticatory muscle tension, stabilizing occlusal support, eliminating occlusal interference and adjusting jaw position can be achieved, so as to eliminate some risk factors of MMD and relief the pain faster.

Temporomandibular Disorders, Bruxism, Perceived Stress, and Coping Strategies among Medical University Students in Times of Social Isolation during Outbreak of COVID-19 Pandemic.

The COVID-19 pandemic caught universities along with their students off-guard, enforcing online education. Fear of the unknown, disinformation, and isolation resulted in an increased stress level in the entire population. Medical university students are particularly endangered with high stress levels and developing TMD. Temporomandibular disorders (TMD) are of multifactorial etiology, and manifest with jaw dysfunction, masticatory muscle tension or pain, as well as headache. Though bruxism can act as an exacerbating factor for TMD, stress can also play crucial role in the onset. The study aimed to measure occurrence of TMD and bruxism symptoms in the medical student population, asses the stress level, and evaluate adopted stress-coping strategies during the COVID-19 pandemic outbreak. A survey study was performed among 1018 students at Medical University of Lodz during April 2020. A self-designed questionnaire for screening TMD and bruxism symptoms, Perceived Stress Scale (PSS-10), and Brief-COPE questionnaires were applied. TMD and bruxism symptoms were observed in the majority of subjects during social isolation. The perceived stress levels were significantly higher in those experiencing TMD and bruxism symptoms. Mostly maladaptive, emotion-focused coping strategies were chosen by study subjects experiencing high levels of stress. Choosing Self-Blaming as a coping strategy is the strongest predictor of perceived stress.

Short-term Effects of a First-Line Treatment Including Counseling and Self-Management Strategies on Chronic TMD Muscle Pain and Awake Bruxism in Women.

To evaluate the short-term effects of a standardized first-line noninvasive approach (FL-A) including counseling and self-management strategies on pain, masticatory muscle tenderness, and awake bruxism in women with chronic temporomandibular disorder myalgia (mTMD) and to test whether patients' trait anxiety predicted their response to treatment. FL-A was administered to 14 women with chronic mTMD (mean age ± SD = 33.8 ± 11.1 years; 8 with Graded Chronic Pain Scale [GCPS] grade I and 6 with grade II). Its effects on facial pain, masticatory muscle tenderness, and spontaneous awake bruxism episodes were evaluated using questionnaires, surface electromyography, and quantitative sensory testing. General linear models were used to test FL-A efficacy after 1 (T1) and 2 (T2) months. FL-A reduced pain (from baseline [T0] to T2, P = .010), the frequency of awake bruxism episodes (T0 to T1, P = .024), and their intensity by about 30% (T0 to T1, P < .001). Pressure pain thresholds at the masticatory muscle locations increased significantly from T0 to T2 (P < .001). Patients' trait anxiety decreased significantly from T0 to T2 (P = .030). Trait anxiety measured at baseline was not correlated with relative changes in pain (T0 to T2, P = .248). In the short term, FL-A reduces facial pain, masticatory muscle tenderness, and awake bruxism in women with chronic mTMD with low disability. A conservative management strategy should be prioritized for the initial management of these patients.

The Importance of Type D Personality in the Development of Temporomandibular Disorders (TMDs) and Depression in Students during the COVID-19 Pandemic

Background: a type D personality is a factor in a person’s susceptibility to general mental stress, especially during the COVID-19 pandemic. Although many studies were conducted on the relationships among stressful situations, an individual’s personality, depression, and the occurrence of various diseases, e.g., cardiovascular disease or cancer, there are no analogous data on people with temporomandibular disorders (TMDs). Aim: the assessment of TMDs and depression symptoms in students with type D personality. Material and Methods: the research was carried out with the participation of 240 physiotherapy students. The study group (G1) consisted of 120 participants with type D personalities, the control group (G2) consisted of the same number of participants, without “stress” personalities. All subjects were assessed for the occurrence of TMD symptoms, as well as for depression and anxiety symptoms, using the Beck Depression Inventory (BDI), based on the proprietary questionnaire. Results: in students with type D personality symptoms, TMDs occurred significantly more often and in greater number (p = 0.00) than in those without stress personalities. The exception was the symptom of increased muscle tension, which showed no statistical difference (p = 0.22). Among the 240 respondents, depression was found in 128 people (53.3%). In the group of students with type D personalities, depression was significantly more frequent than in the group without type D personalities (p = 0.00). In participants with depression, TMD symptoms were more common, i.e., headaches, neck, and shoulder girdle pain, TMJ acoustic symptoms, increased masticatory muscle tension, teeth clenching, and teeth grinding. There was no significant difference between the incidence of depression and TMJ pain and jaw locking. There was a significant interaction between the occurrence of headaches and acoustic symptoms and the occurrence of depression. For headache and depression interactions, the OR was >1; based on the results, we may assume that a headache depends more on the occurrence of depression rather than it being a symptom of a TMJ disorder in people with type D personalities. Conclusion: type D personality and depression may contribute to the development of TMD symptoms.

Impact of clear aligner therapy on tooth pain and masticatory muscle soreness.

Clinical findings suggest that orthodontic treatment with clear aligners (clear aligner therapy/CAT) may cause masticatory muscle soreness in some patients. This multi-site prospective study investigated tooth pain and masticatory muscle soreness and tenderness in patients undergoing CAT and explored whether psychological traits affected these outcomes. Twenty-seven adults (22F, 5M; mean age±SD=35.3±17.6years) about to start CAT were recruited at three clinics. During CAT, they reported on 100-mm visual analogue scales their tooth pain, masticatory muscle soreness and stress three times per day over 4weeks (week 1=baseline; week 2=dummy aligner; week 3=first active aligner; week 4=second active aligner). Pressure pain thresholds (PPTs) were measured at the masseter and temporalis at baseline and after week 4. Mixed models were used to evaluate the outcome measures over time. Clear aligner therapy caused mild tooth pain, which was greater with the passive than the first and second active aligners (both P<.001). Mild and clinically not relevant masticatory muscle soreness was produced by all aligners (all P<.05), with the first active aligner producing less soreness than the dummy aligner (P<.001). PPTs did not change significantly after 4weeks. Both tooth pain and masticatory muscle soreness were affected by stress and trait anxiety, whilst muscle soreness was affected also by oral behaviours. In the short term, CAT produces tooth pain and masticatory muscle soreness of limited significance. Frequent oral behaviours are related to increased masticatory muscle soreness during CAT. The medium- and long-term effects of CAT should be further explored.

Effects of Dysphagia Treatment Applied to Infants with Pierre Robin Syndrome – Single Subject Research Design

Pierre Robin syndrome is characterized by micrognathia, glossoptosis, and cleft palate. Infants with Pierre Robin syndrome causes feeding difficulty, upper airway obstruction, and other symptoms. This study aims to examine the effects of applying dysphagia treatment to infants with Pierre Robin syndrome. The study participant was an infant who was born four weeks premature and referred for dysphagia treatment approximately 100 days after birth. At the initial assessment, the infant showed oral sensory sensitivity, a high level of facial and masticatory muscle tension, and a low stability of the chin and cheeks with almost no normal “sucking-swallowing-breathing” pattern. We set the baseline period and intervention period using the AB design. During the baseline period, non-nutritive sucking training using a rubber nipple was conducted without implementing an oral stimulation intervention. During the intervention period, non-nutritive sucking training and an oral stimulation intervention were performed. After the intervention period, the infant’s daily oral intake and oral intake per time significantly increased compared to that during the baseline period. We observed that the oral intake time of the infant decreased during the intervention period compared to that in the baseline period, which indicated an improvement in control over the chin, tongue, and lip movements, a change in muscular tension, and stabilization of the “sucking-swallowing-breathing” pattern. We provided dysphagia treatment before breastfeeding, it was positive effects such as normal development of the infant, transition from tube feeding to bottle feeding, and enhancement of overall oral motor function.

Efficacy of Low-Level Laser, Hard Occlusal Appliance and Conventional Pharmacotherapy in the Management of Myofascial Pain Dysfunction Syndrome; A Preliminary Study.

Introduction: Myofascial pain dysfunction syndrome (MPDS) is a common temporomandibular joint disorder. Due to its multifactorial etiology, treatment usually involves more than one modality to obtain complementary results. The purpose of this study was to compare the combined effect of a low-level laser, a hard occlusal appliance, and conventional pharmacotherapy with pharmacotherapy only in the management of patients with MPDS. Methods: In this study, 15 patients with MPDS were diagnosed and randomly assigned to 3 groups (n=5). Subjects in Group 1 were treated with pharmacotherapy (PT); Group 2 received the diode laser (940 nm gallium arsenide) every other day for a total of 10 sessions, plus pharmacotherapy (PTL) and Group 3 were given hard occlusal splint 12 h/day for 4 weeks, plus pharmacotherapy (PTO). The intensity of pain was measured using the visual analog scale (VAS) prior to the treatment, 2 and 4 weeks after the onset of treatment and 2 weeks later. The maximum painless mouth opening and pain intensity at muscle palpation were also recorded. Comparisons were made between the groups via repeated measure analysis of variance (ANOVA) (P<0.05). Results: Pain relief in the subjective VAS was observed in both laser and appliance groups in the third and fourth examination sessions (P<0.05). No statistically significant reduction in pain was noted using pharmacotherapy only. The maximum painless mouth opening and muscle tenderness were not significantly different between the 3 groups (P>0.05). Conclusion: Both the laser and the occlusal appliance combined with pharmacotherapy proved to be effective for pain reduction in patients with MPDS. All groups, however, failed to result in a significant improvement in the maximum mouth opening or tenderness in masticatory muscles.

Efficacy of Prolotherapy in Temporomandibular Joint Disorders: An Exploratory Study

Temporomandibular joint (TMJ) disorders can be treated by both conservative and surgical approaches. Conservative interventions with predictable benefits can be considered as first-line treatment for such disorders. Dextrose prolotherapy is one of the most promising approaches in the management of TMDs, especially in refractory cases where other conservative management has failed. To study the efficacy of prolotherapy and to establish it as an effective procedure in patients with TMJ disorders, to provide long-term solution to chronic TMJ pain and dysfunctions. We conducted a study on 25 patients suffering from various TMJ disorders who were treated with prolotherapy, the solution consisting of 1 part of 50% dextrose (0.75ml); 2 parts of lidocaine (1.5ml); and 1 part of warm saline (0.75ml). The standard programme is to repeat the injections three times, at 2-week interval, which totals four injection appointments over 6weeks with 3-month follow-up. There was appreciable reduction in tenderness in TMJ and masticatory muscles with significant improvement in mouth opening. The effect of the treatment in improving clicking and deviation of TMJ was found to be statistically significant (P < 0.05). There were no permanent complications. Our study concluded that prolotherapy is an effective therapeutic modality that reduces TMJ pain, improves joint stability and range of motion in a majority of patients. It can be a first-line treatment option as it is safe, economical and an easy procedure associated with minimal morbidity.

Predictive factors in temporomandibular joint arthroscopy: a prospective cohort short-term outcome study

Improving the outcomes of surgical treatment of the temporomandibular joint (TMJ) is beneficial from a patient and health-economy perspective. Optimizing conditions for a successful result can be reached using validated, strict diagnostic criteria and by identifying patient-specific factors predicting the outcome. The aim of this study was to investigate possible predictive factors in TMJ arthroscopy. A prospective cohort study including 93 patients undergoing arthroscopy was conducted. The outcome was graded as successful (53%, n=49), good (25%, n=23), intermediate (20%, n=19), or deteriorated (2%, n=2) using a predefined set of objective and subjective outcome measures. The outcome was correlated with preoperative and perioperative variables and the diagnosis. Preoperative bilateral masticatory muscle tenderness on palpation was the only variable significantly correlated with a negative outcome in the adjusted regression analysis (odds ratio (OR) 2.56, P=0.048). Low age (OR 1.03, P=0.05) and bilateral joint surgery/operated side (OR 0.24, P=0.05) were found to correlate with an unsuccessful outcome in the unadjusted analysis. Eighty-nine percent of the patients with osteoarthritis benefited from arthroscopy, while corresponding figures were 80% for disc displacement without reduction and 64% for chronic inflammatory arthritis. Preoperative bilateral masticatory tenderness might be a useful predictive factor suggesting the consideration of revised non-invasive therapy before surgery.

Masticatory muscle tenderness in burning mouth syndrome: A case control study

The aim of this study is to evaluate the masticatory muscle tenderness in burning mouth syndrome (BMS) patients. A total of 102 patients (48 with BMS and 54 with non-BMS) that attended the Department of Oral Medicine (Chosun University Dental Hospital, Gwangju, Korea) from January 2018 to December 2018 were included in the study. The pain duration, pain perception using a visual analogue scale and presence of masticatory muscle tenderness was compared between the BMS and non-BMS group. About 85.4% of the BMS patients reported pain or tenderness when the masticatory muscle was palpated. There was a statistically significant association between the BMS symptom and masticatory muscle tenderness. This study suggests that the masticatory muscle tenderness could be related to the BMS. Further study is needed to explore the relationship between the BMS and temporomandibular disorder.

Oral parafunctions, personality traits, anxiety and their association with signs and symptoms of temporomandibular disorders in the adolescents.

To investigate the association between oral parafunctions, personality traits, anxiety and signs and symptoms of temporomandibular disorders in the adolescents. Two hundred and seventy adolescents were examined clinically for the signs and symptoms of temporomandibular disorders. Participants completed questionnaires about demographic variables, medical history, symptoms of temporomandibular disorders, parafunctional oral habits, Minnesota Multibasic Personality Inventory, and Spielberger State-Trait Anxiety Inventory. Logistic regression analyses revealed that bruxism was associated with joint tenderness (Odds ratio (OR)=6.38, p < 0.01), joint noises (OR=6.02, p < 0.01) and masticatory muscle tenderness (OR=4.19, p < 0.05) to palpation. State anxiety showed increased risk of joint tenderness (OR=2.47, p < 0.05) and muscle tenderness (OR=3.25, p < 0.05) to palpation. Within the limitations of this study, it was concluded that oral parafunctions, especially bruxism, state anxiety, depression and hysteria were associated with signs and symptoms of temporomandibular disorders in adolescents.

The Relationship between Signs and Symptoms of Tempromandibular Joint Disorders (TMDs) and Primary Headache

The aims of this study are to investigate the relationship of the concurrent signs and symptoms of a painful TMD with primary headache (migraine and tension type headache) and whether tenderness and provocation of the masticatory system resulted in the headache. Methods and materials : The sample consists of 120 patients which were diagnosed as having temporomandibular joint disorder (TMD) included Research Diagnostic Criteria (RDC). The sample age range was between (18-50 years) . All patients oriented to com- plete the Research Diagnostic Criteria RDC\TMD .The questionnaire for TMD index was also applied to all patients to measure the severity of TMD . Then all patients were subjected to clinical examination (examination of masticatory muscles, joint palpation and deviation, clicking and limitation in mouth opening). Primary Headaches were assessed using a validated structured questionnaire captured information on distinguishing headache features and parallels the International Classification for Headache Disorders-II. Results : females were shown high prevalence of TMDs and headache more than male. The presence of the masticatory muscles pain, joint pain, limitation in mouth opening, clicking and bruxism as well as headache pain intensity and duration, increased to a relevant and statistically significant degree in both migraine and tension type headache patients in compare to other patients had no headache or patients with headache from TMDs. Conclusions: High prevalence of TMD in females and also females represent a majority of headache patients. Clinical pain charac- teristics and masticatory muscle tenderness of TMD are greater in patients with primary headache.

Patient-Specific Factors Predicting Outcome of Temporomandibular Joint Arthroscopy: A 6-Year Retrospective Study

Although indications for the surgical treatment of internal derangement of the temporomandibular joint (TMJ) and the choice of treatment are debated, arthroscopy seems generally accepted as a minimally invasive alternative. The objective of this study was to investigate various factors and their possible correlation with an unsuccessful outcome of arthroscopic lysis and lavage in patients diagnosed with chronic closed lock, arthralgia with or without concomitant osteoarthritis of the TMJ, or systemic rheumatologic disease with involvement of the TMJ. A retrospective analysis of 224 operations was conducted to identify pre-, peri-, and postoperative factors correlated with an adverse outcome. Criteria for success were maximum interincisal opening (MIO) of at least 35mm and self-graded joint pain on a 10-point visual analog scale no higher than3. Surgical outcome was graded as successful (n=150; 67%), improved (n=16; 7%), minor or no improvement (n=55; 25%), or worse (n=3; 1%). Preoperative factors that correlated with a negative outcome were the presence of psychiatric disorders (P=.0333), high self-graded global pain (P=.0320), bilateral muscle tenderness at palpation (P=.0309), and small MIO (P=.0018). For patients with systemic arthritis, younger age was correlated with an unsuccessful outcome (P=.0317). The results indicate that psychiatric comorbidities, high self-graded global pain, bilateral masticatory muscle tenderness, and small MIO predict an unsuccessful outcome after arthroscopic lysis and lavage. These factors could be indicators for chronic pain disorders, including chronic myofascial pain, increased pain sensitivity, and decreased coping abilities, associated with a poor outcome.

IncobotulinumtoxinA Injection for Temporomandibular Joint Disorder.

Temporomandibular disorder (TMD) involves dysfunction of the temporomandibular joint and associated muscles of mastication causing pain with chewing, limitation of jaw movement, and pain. While the exact pathophysiology of TMD is not completely understood, it is thought that hyperfunction of the muscles of mastication places stress on the temporomandibular joint, leading to degeneration of the joint and associated symptoms. We hypothesize that chemodenervation of the muscles of mastication with IncobotulinumtoxinA (Xeomin) will decrease the stress on the temporomandibular joint and improve pain associated with temporomandibular joint and muscle disorder (TMJD). Twenty patients were randomized to IncobotulinumtoxinA (170 units) or saline injection of the masticatory muscles. Patient-reported pain scale (0-10) was recorded at 4-week intervals following injection for 16 weeks. Patients who received saline injection initially were assessed for reduction in pain at the first 4-week interval and if still had significant pain were rolled over into the IncobotulinumtoxinA arm. Preinjection pain scores were similar between patients. While there was a statistically significant reduction in pain score in the placebo group one month, there was an overall larger drop in average pain scores in those patients injected with IncobotulinumtoxinA initially. All patients initially injected with placebo crossed over into the IncobotulinumtoxinA group. Similar results were seen when examining the composite masticatory muscle tenderness scores. There was no significant change in usage of pain medication. We demonstrate utility of IncobotulinumtoxinA in treating patients with TMD with pain despite pain medication usage and other conventional treatments.

Association between patterns of jaw motor activity during sleep and clinical signs and symptoms of sleep bruxism.

The aim of this study was to investigate the association between patterns of jaw motor activity during sleep and clinical signs and symptoms of sleep bruxism. A total of 35 university students and staff members participated in this study after providing informed consent. All participants were divided into either a sleep bruxism group (n=21) or a control group (n=14), based on the following clinical diagnostic criteria: (1) reports of tooth-grinding sounds for at least two nights a week during the preceding 6months by their sleep partner; (2) presence of tooth attrition with exposed dentin; (3) reports of morning masticatory muscle fatigue or tenderness; and (4) presence of masseter muscle hypertrophy. Video-polysomnography was performed in the sleep laboratory for two nights. Sleep bruxism episodes were measured using masseter electromyography, visually inspected and then categorized into phasic or tonic episodes. Phasic episodes were categorized further into episodes with or without grinding sounds as evaluated by audio signals. Sleep bruxism subjects with reported grinding sounds had a significantly higher total number of phasic episodes with grinding sounds than subjects without reported grinding sounds or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). Similarly, sleep bruxism subjects with tooth attrition exhibited significantly longer phasic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). Furthermore, sleep bruxism subjects with morning masticatory muscle fatigue or tenderness exhibited significantly longer tonic burst durations than those without or controls (Kruskal-Wallis/Steel-Dwass tests; P<0.05). These results suggest that each clinical sign and symptom of sleep bruxism represents different aspects of jaw motor activity during sleep.

Longitudinal Multilevel Modeling of Facial Pain, Muscle Tension, and Stress

The role of masticatory muscle activation on pain in temporomandibular muscle and joint disorders (TMJD) is controversial. This single-group, prospective panel study examined the relationships among masticatory muscle tension, emotional distress, and TMJD pain in a sample of 7,023 observations obtained from 171 individuals using longitudinal multilevel modeling. Three main hypotheses were tested. The first posited that emotional distress and muscle tension directly influenced pain (hypothesis 1a: Distress → TMJD Pain; hypothesis 1b: Muscle Tension → TMJD Pain). The second posited that emotional distress directly influenced muscle tension (Distress → Muscle Tension), and the third posited that the effect of emotional distress on pain was mediated by muscle tension (Distress → Muscle Tension → TMJD pain). We also examined the fit of the data to possible alternative models. All the data used in this study were collected via an experience sampling methodology. The fit of the preferred models was better than that of the alternative models, with the preferred models explaining large proportions of the data, especially for level 2 variance (hypothesis 1a = 41% variance; hypothesis 1b = 69% variance; hypothesis 2 = 48% variance). In the mediation model, the addition of muscle tension to the model reduced the impact of emotional distress. The findings support a causal role for masticatory muscle tension in TMJD pain. Clinically, the results suggest that addressing tension and other oral parafunctions in those diagnosed with TMJDs should be an important part of the conservative, noninvasive care of individuals diagnosed with the myofascial pain or arthralgia of TMJD.