The role of tryptophan and its derivatives in musculoskeletal pains: A systematic review and meta-analysis.

BACKGROUND: Studies present ambiguous findings regarding the role of tryptophan and its metabolites, kynurenine and serotonin in chronic musculoskeletal pain. This systematic review aimed to investigate the expression of tryptophan and its metabolites, serotonin and kynurenine in patients with local and generalized chronic musculoskeletal pain in comparison with pain-free controls. METHODS: An electronic search was conducted in the databases MEDLINE, CINAHL, EMBASE, the Cochrane Central Registry of Controlled Trials (CENTRAL) and Web of Science for clinical and observational trials from the beginning of each database to 21 April 2023. Out of 6734 articles, a total of 17 studies were included; 12 studies were used in the meta-analysis of serotonin, 3 regarding tryptophan and 2 studies for a narrative synthesis regarding kynurenine. Risk of bias was assessed using the quality assessment tool for observational cohort and cross-sectional studies of the National Heart, Lung, and Blood Institute, while the certainty of evidence was by GRADE. RESULTS: All included studies showed a low risk of bias. The meta-analysis showed lower blood levels of tryptophan (p < .001; very low quality of evidence) and higher blood levels of serotonin (p < .001; very low-quality evidence) in patients with generalized musculoskeletal pain, when compared to pain-free individuals. In local chronic musculoskeletal pain, there were higher blood levels of serotonin (p=.251; very low quality of evidence) compared to pain-free individuals. Regarding kynurenine, the studies reported both higher and lower blood levels in generalized chronic musculoskeletal pain compared to pain-free individuals. CONCLUSIONS: The blood levels of tryptophan and its metabolites serotonin and kynurenine seem to influence chronic musculoskeletal pain.

Temporalis Muscle Changes Following Botulinum Toxin A Injections in Masseter Hypertrophy Patients: A Randomized Triple-Blinded Trial.

BACKGROUND: This study aimed to elucidate the effects of botulinum toxin A (BoNT-A) treatment for patients diagnosed with masseter hypertrophy on the temporalis muscle, with a particular focus on assessing alterations in muscle thickness, electromyographic (EMG) activity, and the development of muscle pain. METHODS: The present randomized triple-blinded clinical trial enrolled 26 female participants aged between 25 and 50 years complaining about masseter hypertrophy. Participants received 75U of BoNT-A (abobotulinumtoxinA) in both masseter muscles and after three months were randomized to receive a second treatment session of saline solution (S-BoNT-A) or BoNT-A (M-BoNT-A). Longitudinal assessments included temporalis muscle thickness through ultrasound, EMG activity, subjective pain, and masseter prominence severity after one, three, and six months of the first injection session. Muscle thickness, EMG, and subjective pain were analysed using two-way ANOVA with repeated measures and post hoc Sidak test, and for masseter prominence severity, Friedman and Mann-Whitney tests were used. RESULTS: Regarding inter-group comparisons, a higher muscle thickness (p < 0.02) and a higher EMG activity (p < 0.01) were found in the M-BoNT-A group at the 6-month follow-up. For subjective pain assessments, inter-group comparisons showed a higher prevalence of painful regions in M-BoNT-A group at the 6-month follow-up (p < 0.02). No significant differences were found in masseter prominence severity at the 6 months assessment between groups. CONCLUSION: BoNT-A treatment for masseter hypertrophy lead to structural and functional changes in the temporalis muscle, presenting higher changes after multiple injections of this treatment. LEVEL OF EVIDENCE I: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Trial data for precision analysis of a three-dimensional mandibular mechanical advantage.

The data presented in this manuscript describe craniofacial landmark coordinate values, muscle and load moment arm lengths, and mechanical advantage rates for constructing a three-dimensional model of masticatory muscles. Cone-beam computed tomography scans from 30 subjects (aged 12-19 years, 16 females) were used. Thirty-six craniofacial landmarks were identified. Subsequently, the moment arms for 7 muscles and their corresponding load moment arms at incisor and molar positions were determined. Then, the three-dimensional mechanical advantage for each muscle and tooth position was calculated as the ratio of muscle moment arm to load moment arm. This procedure was repeated three times by a main examiner and once by two other examiners. The Friedman test and the square root of the 'method of moments' variance estimator were used to compare data among examiners and calculate random errors, respectively. Although the values for the craniofacial landmark coordinates and biomechanical variables are very close, differences were found between measurements, especially in the interexaminer comparisons. Values served as the basis for reliability (intraclass correlation coefficient) and errors (average mean of absolute differences) analysis in the research paper titled "A three-dimensional method to calculate mechanical advantage in mandibular function: Intra- and interexaminer reliability study," published in the Journal of Orofacial Orthopedics.

Somatosensory and psychosocial profile of migraine patients: A cross-sectional study.

BACKGROUND: Migraine is a chronic neurological disorder that involves the brain, characterized by a series of abnormal neuronal networks interacting at different levels of the central and peripheral nervous system. Furthermore, it is known that psychosocial features contribute to the exacerbation and chronicity of symptoms. OBJECTIVE: To compare the somatosensory and psychosocial profiles of migraine patients with a control group. METHODS: We conducted a cross-sectional study comparing the somatosensory and psychosocial profiles of patients with migraine and healthy volunteers. A total of 52 women were included. For the somatosensory profile, Mechanical Detection Threshold (MDT), Pressure Pain Threshold (PPT), Temporal Summation (TS), and Conditioned Pain Modulation (CPM) in the trigeminal and extra-trigeminal areas were evaluated. Psychosocial profiles were assessed using questionnaires, the Central Sensitization Inventory, the Generalized Anxiety Disorders, the Pain Catastrophizing Scale, and the Tampa Scale of Kinesiophobia. Mann-Whitney U test was used to compare differences in the profiles between groups. The significance level was set at 5%. RESULTS: Migraine patients showed a loss of somatosensory function in the trigeminal area for MDT (p = 0.019, r = 0.34 and p = 0.011, r = 0.37 for the ophthalmic nerve and masseter muscle respectively), lower PPT in trigeminal and extra-trigeminal areas (p < 0.001, r=>0.60) and less efficient CPM (p < 0.001, r=>0.60). No statistically significant differences were found in the TS (p=>0.05). Statistically significant differences were found in all psychosocial variables (p = <0.001 r=>0.60). CONCLUSION: Migraine patients showed loss of somatosensory function, lower pressure pain threshold, and an inhibitory pro-nociceptive profile with high scores on central sensitization and fear of movement compared to the control group.

Benefits of the combination of digital and analogic tools as a strategy to control possible awake bruxism: A randomised clinical trial.

BACKGROUND: Awake Bruxism (AB) management includes cognitive and behavioural changes. Digital and analogic tools can be used to remind the individual to control/avoid AB behaviours. However, no study addressed both tools together. OBJECTIVE: To compare the efficacy of the combination of digital (smartphone application) and analogic (adhesive reminders) tools versus digital tool alone for AB management. METHODS: Seventy-two individuals diagnosed with probable AB were divided into 3 groups: Group 1 (n = 24), used both digital and analogic tools during 30 days; Group 2 (n = 24), used only a digital tool during 30 days and Group 3 (n = 24), used only a digital tool for the first 15 days and then added the analogic tool for 15 days. The AB frequency was measured in real-time with a smartphone app, which sent alerts asking the individuals if they were doing any AB behaviours (bracing, teeth contact, clenching or grinding). Groups were compared using one-way ANOVA and before-after adding an analogic tool (group 3) by paired t-test, considering α = 0.05. RESULTS: All groups showed a decrease in AB behaviours at the end of the evaluation period. Group 1 (digital and analogic tools) showed the lowest average of AB behaviours among all groups; however, statistically significant differences were found only for the comparison between groups 1 and 2. In group 3, a significantly greater reduction in AB behaviours was found after combining both approaches. CONCLUSION: The combination of digital and analogic tools showed the greatest reduction of AB frequency and can be recommended for AB control.

Sociodemographic Profile: A Forgotten Factor in Temporomandibular Disorders? A Scoping Review.

The literature on Temporomandibular Disorders (TMD) incidence commonly reports sociodemographic factors such as gender and age. However, the role and prevalence of other sociodemographic factors in TMD are not well defined. Therefore, this scoping review aimed to report the prevalence of sociodemographic factors in TMD patients. A systematic search was conducted in the PubMed and Web of Science databases to identify clinical trials in adult populations, using the Research Diagnostic Criteria for TMD (RDC/TMD) or the Diagnostic Criteria for TMD (DC/TMD) and reporting sociodemographic data in TMD patients. Twenty-seven studies meeting the criteria were included in this review. The most commonly reported sociodemographic factors assessed in the included studies were age, race, education, job, income, and marital status. TMD prevalence was observed to be higher among younger and divorced individuals among the included studies. However, conflicting results were found for education level, and employment was not considered a risk factor for TMD. Although this review has methodological limitations, it suggests an association between TMD incidence and certain sociodemographic factors; nevertheless, further studies are needed to establish this relationship more conclusively.

Botulinum toxin-A effects on pain, somatosensory and psychosocial features of patients with refractory masticatory myofascial pain: a randomized double-blind clinical trial.

The antinociceptive effect of BoNT-A have been well documented in animal studies; however, results of few but well-designed randomized placebo-controlled clinical trials about BoNT-A efficacy in masticatory myofascial pain (MFP) are inconsistent. Therefore, the present randomized, double-blind, placebo-controlled clinical trial evaluated the efficacy of BoNT-A in patients with refractory MFP. Twenty-eight patients with pain reduction of less than 30% despite conservative treatment and with an average pain intensity of > 50 mm on the visual analogue scale (VAS) participated. Patients were randomly assigned to receive a total of 80 U of BoNT-A or saline solution (SS) injected into the masseter and anterior temporalis muscles. Pain intensity (VAS), quantitative sensory testing (QST), conditioned pain modulation (CPM), and psychosocial status were examined. Follow-up was performed at 1 and 6 months. For repeated-measure comparisons between evaluation times, Friedman test with Bonferroni correction was used for pain and somatosensory variables and the Wilcoxon test for the psychosocial variables. The Mann-Whitney test was used for all comparisons between groups. The BoNT-A group had a significant decrease in pain intensity at follow-ups compared with the SS group (p < 0.001). QST assessment revealed higher pressure pain threshold values in the masseter muscle for BoNT-A group compared to SS (p < 0.03) at all follow-ups. No differences were found for mechanical pain threshold and wind-up ratio values (p > 0.05) in the entire study. The BoNT-A group presented the most efficient CPM effect (p < 0.03) only at the 1 month follow-up in the masseter muscle. There was a significant time effect for BoNT-A in all psychosocial variables (p < 0.05) and a drug effect in the Central Sensitization Inventory (p < 0.01), Pittsburgh Sleep Quality Index (p < 0.004), and Healthy Survey 36 (p < 0.05) at 6 months follow-up. The study demonstrates that a single injection-session of BoNT-A has positive effects on the hall pain spectrum of patients with refractory masticatory myofascial pain.

Influence of the radius of Monson's sphere and excursive occlusal contacts on masticatory function of dentate subjects.

OBJECTIVE: To determine the influence of the radius of Monson's sphere, the number of posterior laterotrusive, mediotrusive, and protrusive contacts, and the chewing rate on food comminution. DESIGN: Sixty healthy dentate subjects, aged 21.22 ± 2.30 years, were selected. The three-dimensional coordinates of the cusp tips of the lower canine, premolar, and molar teeth were identified from the subjects' digital models. Monson's sphere was designed using the simplex method for function minimisation by adjusting the coordinates on its surface. The contacts were verified using 12 µm metal strips in jaw excursions at 0.5, 1.0, 2.0, and 3.0 mm. The masticatory performance and efficiency, swallowing threshold, and chewing rate were assessed through particle size fractionation. Data were analysed with multiple linear regression (α = 0.05). RESULTS: The sphere's radius, laterotrusive and protrusive contacts at 0.5 mm, and chewing rate were found to be negative predictor variables for masticatory performance until 20 chewing cycles (R2 = 0.429). For 40 cycles, the radius and total contacts (0.5 mm) were also explanatory factors (R2 = 0.223). Only the radius (R2 = 0.176) and the chewing rate (R2 = 0.082) were found to be significant for 60 cycles and swallowing threshold, respectively. Masticatory efficiency was influenced by masticatory performance until 40 and 60 cycles, as well as the radius and total contacts at 2.0 and 3.0 mm (R2 = 0.958). CONCLUSION: A larger radius of Monson's sphere and a greater number of posterior excursive contacts were found to be related to better masticatory function.

Comparison of the Effectiveness of Different Methods for Pain Reduction During Injection Procedures in the Frontalis Muscle.

BACKGROUND: Forehead aesthetic injections are a well-known source of discomfort, and many analgesic non-invasive techniques have been proposed to ameliorate pain. However, no study has compared all these techniques for aesthetic purposes. Therefore, this study aimed to compare the effectiveness of topical cream anesthesia, vibratory stimulus, cryotherapy, pressure, and even no intervention, on pain during and immediately after injection, when considering aesthetic injections in the forehead. METHODS: Seventy patients were selected and had their foreheads divided into 5 parts, which received four different analgesic techniques, and one control zone was added. A numeric rating scale was used to assess pain, two direct questions were asked to evaluate patients' preference and discomfort with the techniques, and the adverse events were quantified. The injections were performed in the same sequence, with three minutes of rest between them and in a single session. Comparisons among analgesic methods for pain relief were performed by the one-way analysis of variance (ANOVA), considering a significance level of 5%. RESULTS: No significant differences were found among the analgesic methods, and between the methods and the control zone, both during and immediately after the injections (p > 0.05). The preferred method for pain relief was the use of topical anesthetic cream (47%), while the most uncomfortable technique was manual distraction (pressure) (36%). Only one patient reported an adverse event. CONCLUSIONS: No analgesic method to diminish pain was superior to the others or was better than no method. Nevertheless, the topical anesthetic cream was the preferred technique, causing less discomfort. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effect of artificial eccentric occlusal interferences on masticatory performance: A randomised double-blind clinical trial.

BACKGROUND: Occlusal interferences lead to changes in mandibular kinematics to compensate and improve function. However, the effects of different types of eccentric disturbance on the comminution capacity are not known. OBJECTIVE: To determine the immediate effect of eccentric occlusal interferences on masticatory performance. METHODS: This crossover clinical trial included 12 healthy dentate subjects aged 25.2 ± 3.3 years who were randomly submitted to seven types of occlusal interference: unilateral and bilateral laterotrusive and mediotrusive, protrusive, dummy and control (no interference). The interference forms were planned in a semi-adjustable articulator, fabricated with composite resin and adhered to the mandibular first molars such that subjects' maximum intercuspation was maintained. Masticatory performance and the chewing rate during 20 cycles were evaluated during subjects' comminution of silicone test food under one interference condition per test day; the multiple sieve method was applied to the comminuted particles. The interference was removed upon test completion, and a 1-week washout period was applied between tests. RESULTS: Comminuted median particle sizes were larger under unilateral (4.94 ± 0.41 mm) and bilateral (4.81 ± 0.49 mm) laterotrusive, bilateral mediotrusive (4.65 ± 0.50 mm) and protrusive (4.83 ± 0.54 mm) interferences (p < .05) than under the control (4.01 ± 0.52 mm) and dummy (4.18 ± 0.58 mm) conditions (p < .05). Only unilateral and bilateral laterotrusive interferences narrowed the comminuted particle size dispersion (p < .05). The chewing rate did not differ among conditions (p = .1944). CONCLUSION: Artificial eccentric interferences had an immediate adverse effect on masticatory performance by resulting in larger comminuted particles. CLINICAL TRIAL REGISTRATION: Brazilian Registry of Clinical Trials (RBR-8g5zfg8).

Histomorphometric Changes of the Masseter Muscle of Rats After a Single Injection of Botulinum Toxin Type A.

BACKGROUND: It has been reported that botulinum toxin type A (BoNT-A) produces structural changes in masticatory muscles. However, not all histomorphometric parameters affected by BoNT-A parameters have been assessed. This study investigated the histomorphometric changes in the masseter muscle of rats after a single injection of BoNT-A. METHODS: Forty-four adult animals were randomly divided into control group (n = 22) and BoNT-A group (n = 22). Controls received a single dose of 0.14 mL/kg of saline in masseter muscles, and the BoNT-A group received a 7 U/Kg of BoNT-A. The groups received the same volume of injected substances. Animals were sacrificed on 7th (n = 5), 14th (n = 5), 21st (n = 5), 28th (n = 4) and 90th (n = 3) days post-treatment. Histological masseter tissue slides were obtained from hematoxylin-eosin treatment and analyzed in optical microscopy regarding muscle cross-sectional area, amount of connective tissue and quantity and diameter of myocytes. For statistical analysis, generalized linear models were used to compare the data (ANOVA). In all test, the significance level of 5% was set. RESULTS: BoNT-A values of cross-sectional area of the masseter muscle were significantly lower than controls (p < 0.01) throughout the study. Regarding myocytes quantity, BoNT-A subgroups presented higher values than controls (p < 0.0001) since the 14th day until the end of the study; however, the diameter of myocytes was smaller in all BoNT-A subgroups (p < 0.0001) in all assessment points. The amount of connective tissue was higher in BoNT-A subgroups (p < 0.0001) throughout the study. CONCLUSION: A single injection of BoNT-A altered the structure of masseter muscle of rats, regarding its histomorphometric parameters. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Do sociodemographic factors influence the levels of health and oral literacy? A cross-sectional study.

BACKGROUND: Oral health literacy has gained importance in dental literature, and its relationship with oral health status and association with health status (HL) has been reported. Then, an association between the levels of HL and OHL could be expected. This study aimed to assess the levels of HL and OHL according to sociodemographic factors and to explore a possible association between HL and OHL. METHODS: The European Health Literacy Survey and Oral Health Literacy Adults Questionnaire were applied to a convenience sample from Portuguese individuals. Also, sociodemographic factors such as sex, age, schooling level of the participants and their parents, and if the participants were professionals or students of the health field were assessed. To analyze the data, the Kruskal-Wallis and Mann-Whitney U tests were used to compared sociodemographic variables and the levels of literacy in general and oral health. The Spearman correlation test assessed the correlation between the levels of HL and OHL. RESULTS: HL results showed that 45.1% of the volunteers were considered in a "problematic level" and 10.3% in "excellent level". However, 75% presented an adequate level of OHL. Regarding the levels of HL in each sociodemographic variable, significant higher levels of "excellent level" were found in health professionals and students when compared with participants not related to health area (p < 0.001). Comparisons between the levels of OHL in each sociodemographic variable showed, significant differences regarding sex (p < 0.05), age (p < 0.001), levels of schooling of the participants and their parents (p < 0.009 and p < 0.001) and relationship with health field. (p < 0.001). A significant positive - weak correlation was found between HL and OHL (p < 0.001). CONCLUSIONS: HL and OHL levels are associated and could be influenced by sociodemographic factors.

Prevalence of awake bruxism in the adult population: a systematic review and meta-analysis.

OBJECTIVES: To evaluate the prevalence of awake bruxism (AB) in the adult population. MATERIALS AND METHODS: Six main electronic databases and three sources of grey literature were searched to identify cross-sectional studies in which AB was assessed. The studies were independently selected by two reviewers in two phases, based on their eligibility criteria. The first one consisted of reading titles and abstracts, and the second one involved reading the full articles. The study quality assessment was obtained by using the "Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data", and the "R Statistics" software was used to perform meta-analyses. RESULTS: Seventeen out of 3086 identified studies were included. None of the studies scored high in methodological quality across all 9 items of the JBI checklist. However, "the use of valid methods to identify pathology" and "appropriate statistical analysis" were considered to have high methodological quality in all the studies. The overall pooled prevalence of the meta-analysis was 15.44% (99% confidence interval: 10.81 to 20.72%) and there was no difference for sex, sampling method and according to consensus-based classification. CONCLUSIONS: The prevalence of AB in adults was low. There was substantial methodological variability, which highlights the need for standardized guidelines. CLINICAL RELEVANCE: Prevalence data are useful for raising patients' and clinicians' awareness of the AB. Moreover, since AB can lead to possible pain and overload of the stomatognathic system, this knowledge can also guide dentists to achieve an early diagnosis of AB and to provide appropriate care management.

Influence of awake bruxism behaviors on fatigue of the masticatory muscles in healthy young adults.

The present cross-sectional study aimed to analyze the relationship between awake bruxism and fatigue of masticatory muscles in healthy young adults. For this purpose, 121 graduate students participated in this study. Frequency of awake bruxism was collected for 7 consecutive days by ecological momentary assessment (EMA) using an online survey (mentimeter). Muscle fatigue was tested one day after EMA assessment, which consisted of voluntarily and continuously clenching at 30% (kgf/cm2) of maximum bite force (MBF) until exhaustion. The percentage of change in MBF after the clenching task, as compared to the MBF before the clenching task was measured. The average frequency of awake bruxism was 45.5% during 7 days. Sustained clenching resulted in a significant reduction in MBF values in the total sample (p < 0.05). Nevertheless, no significant correlation was found between frequency of awake bruxism behaviors and percent of change in MBF and endurance time during the fatigue test. Therefore, it can be concluded that young healthy adults present a relatively high frequency of awake bruxism behaviors that do not seem to impact the degree of masticatory muscle fatigue.

High Levels of Physical Activity Reduce the Esthetic Durability of Botulinum Toxin Type A: A Controlled Single-Blind Clinical Trial.

The present study aimed to evaluate the influence of physical activity on the durability of the esthetic effect of botulinum toxin type A (BoNT-A). Sixty female patients were allocated to three groups (n = 20) according to their physical activity level (PA): Low PA, Moderate PA, and High PA. All groups received a single injection of onabotulinumtoxinA, considering standardized doses in the frontalis (12U), corrugator supercilia (7U, each), and procerus muscles (4U). Outcomes were measured using electromyography (EMG), Merz 5-point scales, and Face-Q scales (perceived age and lines between eyebrows). A follow-up occurred after 30, 60, and 90 days. EMG results showed a significant decrease in muscle activity in the Low-PA group at all follow-ups compared with the other groups (p < 0.001). The Merz scale scores showed that the severity of forehead and glabellar lines significantly improved in the Low-PA group throughout this study compared with the other groups (p < 0.001). No significant differences between groups were found in the Face-Q scale for perceived age, while the Face-Q scale for lines between eyebrows showed better results for Low-PA (p < 0.01) and Moderate-PA (p < 0.01) groups compared to the High-PA group at the 30- and 90-day follow-ups. The durability of the esthetic effect of BoNT-A seems to be negatively influenced by the level of physical activity.

Influence of awake bruxism behaviors on fatigue of the masticatory muscles in healthy young adults

Abstract The present cross-sectional study aimed to analyze the relationship between awake bruxism and fatigue of masticatory muscles in healthy young adults. For this purpose, 121 graduate students participated in this study. Frequency of awake bruxism was collected for 7 consecutive days by ecological momentary assessment (EMA) using an online survey (mentimeter). Muscle fatigue was tested one day after EMA assessment, which consisted of voluntarily and continuously clenching at 30% (kgf/cm2) of maximum bite force (MBF) until exhaustion. The percentage of change in MBF after the clenching task, as compared to the MBF before the clenching task was measured. The average frequency of awake bruxism was 45.5% during 7 days. Sustained clenching resulted in a significant reduction in MBF values in the total sample (p < 0.05). Nevertheless, no significant correlation was found between frequency of awake bruxism behaviors and percent of change in MBF and endurance time during the fatigue test. Therefore, it can be concluded that young healthy adults present a relatively high frequency of awake bruxism behaviors that do not seem to impact the degree of masticatory muscle fatigue.

Long-Term Effects of a Single Application of Botulinum Toxin Type A in Temporomandibular Myofascial Pain Patients: A Controlled Clinical Trial.

This study assessed the long-term effects of botulinum toxin type A (BoNT-A) in subjective pain, pain sensibility, and muscle thickness in persistent myofascial temporomandibular-disorder pain (MFP-TMD) patients. Fourteen female subjects with persistent MFP received BoNT-A treatment with different doses (10U-25U for temporalis muscle and 30U-75U for masseter muscle). The treatment was injected bilaterally in the masseter and anterior temporalis muscles in a single session. Clinical measurements included: self-perceived pain (VAS), pain sensibility (PPT), and muscles thickness (ultrasonography). Follow-up occurred 1, 3, 6, and 72 months after treatment for VAS and PPT and 1, 3, and 72 months for ultrasonography. For statistical analysis, the Friedman test with the Bonferroni test for multiple comparisons as a post hoc test was used for non-parametric repeated measures comparisons among the evaluation times. A 5% probability level was considered significant in all tests. VAS values presented a significant decrease throughout the study (p < 0.05). Regarding PPT values, a significant increase was found when comparing baseline data with post-treatment follow-ups (p < 0.05), and even though a significant decrease was found in muscle thickness when baseline values were compared with the 1- and 3-months assessments, no differences were found when compared with the 72 months follow-up (p > 0.05). A single injection of BoNT-A presents long-term effects in reducing pain in persistent MFP-TMD patients, and a reversibility of adverse effects on masticatory-muscle thickness.

Painful Temporomandibular Joint Clicking: Genetic Point of View.

AIMS: To determine whether there is an association between gene polymorphisms and patients with painful temporomandibular joint (TMJ) clicking when compared to patients with painless TMJ clicking and a healthy control group. METHODS: In this pilot study, the genotypic and allelic frequencies of candidate single-nucleotide polymorphisms (SNP) were compared among 60 individuals divided equally into three groups: patients with painful TMJ clicking (n = 20); patients with painless TMJ clicking (n = 20); and healthy controls (n = 20). Participants were genotyped for the following SNPs using real-time polymerase chain reaction: MMP1 -16071G/2G, COMT Val158Met, TNFα -308, IL1ß +3954, IL6 -174, and IL10 -1082. The pressure pain threshold (PPT) of the TMJ was also assessed. All variables were compared among groups. RESULTS: Patients with painful TMJ clicking had a significant association and a higher frequency of MMP1 -16071G/2G (P = .042), COMT Val158Met (P = .030), and TNFα -308 (P = .016) when compared to the other groups, as well as a lower frequency of IL10 -1082. Considering PPT values, a progressively lower mean was found in individuals with painful TMJ clicking, followed sequentially by the painless TMJ clicking and the control groups. CONCLUSION: This pilot study showed that patients with painful TMJ clicking had a significant association with mutant genotypes related to degradation of extracellular matrix components, pain, proinflammation, and anti-inflammation. Furthermore, these patients also had significantly lower TMJ PPT values in all comparisons.

Efficacy of Botulinum Toxin Type-A I in the Improvement of Mandibular Motion and Muscle Sensibility in Myofascial Pain TMD Subjects: A Randomized Controlled Trial.

This study assessed the effects of botulinum toxin type A (BoNT-A) in mandibular range of motion and muscle tenderness to palpation in persistent myofascial pain (MFP) patients (ReBEC RBR-2d4vvv). Eighty consecutive female subjects with persistent MFP, were randomly divided into four groups (n = 20): three BoNT-A groups with different doses and a saline solution group (placebo control group). Treatments were injected bilaterally in the masseter and anterior temporalis muscle in a single session. Clinical measurements of mandibular movements included: pain-free opening, maximum unassisted and assisted opening, and right and left lateral excursions. Palpation tests were performed bilaterally in the masseter and temporalis muscle. Follow-up occurred 28 and 180 days after treatment. For the statistical analysis the Mann-Whitney U-test with Bonferroni correction was used for groups comparisons. Regardless of dose, all parameters of mandibular range of motion significantly improved after 180 days in all BoNT-A groups, compared with the control group. Palpation pain over the masseter and temporalis muscles were significantly reduced in all BoNT-A groups regardless of dose, compared with the control group, after 28 and 180 days of treatment. Independent of doses, BoNT-A improved mandibular range of motion and muscle tenderness to palpation in persistent MFP patients.

Who is the individual that will complain about temporomandibular joint clicking?

BACKGROUND: Understanding the profile of the individual complaining of TMJ clicking can help in the clinical approach of these patients. OBJECTIVE: To identify clinical variables associated with individuals who complain about and seek treatment for TMJ clicking. METHODS: Seventy-two individuals, composed the sample: Group 1 - patients with a complaint of TMJ clicking who sought treatment; (n = 36); Group 2 - individuals with TMJ clicking who have no complaints about it (n = 36). Three categories of data were evaluated: clinical (gender; age; side of TMJ clicking; TMJ pain; self-reported level of bother; previous TMJ clicking information); somatosensory (mechanical pain threshold [MPT], wind-up ratio [WUR], pressure pain threshold [PPT]); and, psychosocial (Pain Vigilance and Awareness Questionnaire [PVAQ]; Pain Catastrophising Scale [PCS]; Tampa Scale for Kinesiophobia for Temporomandibular Disorders [TSK/TMD]); The Perceived Stress Scale (PSS); The State-Trait Anxiety Inventory (STAI). RESULTS: Group 1 was composed mostly of female patients, with TMJ pain, without previous orientation about the condition, bothered by the clicking, with lower PPT and higher scores in the PVAQ, PCS, TKS/TMD, PSS and STAI scales than Group 2. The groups did not differ significantly for side of TMJ clicking, age, MPT and WUR. CONCLUSION: Individuals who have a TMJ clicking complaint and seek treatment are mostly female, have TMJ pain, have not received previous orientation about TMJ clicking, are bothered by the clicking, have a lower pain threshold and higher scores of hypervigilance, catastrophising, kinesiophobia, stress and anxiety than people with TMJ clicking who do not report it.