Nutrition and chronic musculoskeletal pain: A narrative review and directions for temporomandibular disorder research and management

BACKGROUND

Recent evidence suggests neuro-immune mechanisms may link dietary patterns to chronic painful conditions (CPC). In the research field of oro-facial pain (OFP), studies focuses primarily on dietary mechanical limitations due to pain and dysfunction.

OBJECTIVE

This narrative review aimed to overview the role of nutrition on CPC, with emphasis on temporomandibular disorder (TMD), enlightening OFP researcher on dietary assessment possibilities and providing directions for studies in the field of OFP and nutrition.

METHODS

A PubMed database search was performed using the MeSH and non-MeSH descriptors: "temporomandibular joint disorder"; "orofacial pain"; "musculoskeletal pain"; "chronic pain disorders"; "nutrition"; "diet"; "dietary therapy"; "dietary intake" and "inflammation". No time restrictions were applied. Literature reviews, systematic reviews, meta-analyses and clinical and pre-clinical trials were included.

RESULTS

Exogenous oxidants from unhealthy dietary patterns may contribute to peripheral and central pro-inflammatory immune signalling leading to peripheral and central sensitization. Furthermore, diets rich in bioactive compounds are suggested to contribute to pain management of CPC. High dietary intake of ultra-processed foods impacts the quality of the diet and shows adverse health outcomes. In this context, the role of nutrition on TMD remains overlooked.

CONCLUSION

Considering diet may influence CPC, allied with the scarcity of studies evaluating the role of nutrition on TMD, well-designed clinical trials based on dietary assessments and measurements capable of evaluating food quality, UPF consumption and nutrient adequacy-added to serum nutrient levels evaluation-are suggested.

Influence of psychometric and sleep quality features on painful mechanical sensitivity and pain modulation in patients with temporomandibular disorders

Investigating the collective impact of psychometric properties and sleep quality on pain sensitivity in temporomandibular disorder (TMD) patients could improve clinical management strategies.

OBJECTIVE

Assessing whether combined psychometric properties and sleep quality impact painful mechanical sensitivity and pain modulation in TMD patients.

MATERIALS AND METHODS

A cross-sectional study using secondary data analysis of 77 TMD patients and 101 controls. All participants completed questionnaires characterizing their psychometric profile (anxiety, depression, stress and catastrophizing) and sleep quality, alongside psychophysical tests for painful mechanical sensory (mechanical pain threshold (MPT), pressure pain threshold (PPT), and wind-up ratio (WUR)) and conditioned pain modulation (CPM). Participants were grouped into "High distress" or "Low distress" categories based on psychometric properties and sleep quality using hierarchical cluster and k-means analyses. Multiple linear regression evaluated the influence of TMD, age, and the distress cluster on MPT, WUR, PPT, and CPM in masseter and thenar muscles. Differences were statistically significant when p < 0.05.

RESULTS

The presence of TMD was the strongest predictor of mechanical painful sensitivity in the trigeminal region (MPT[F(3,174) = 51.902;p < .001;R2 = .463]; TMD presence (β = -.682) / PPT[F(3,174) = 15.573;p < .001;R2 = .198] TMD presence (β = -.452), and extra-trigeminal (MPT[F(3,174) = 35.897;p < .001;R2 = .382] TMD (β = -.647) / CPM [F(3,174) = 4.106;p < .05;R2 = .050] TMD presence (β = .197). Furthermore, neither the high distress group nor the low distress group were able to significantly influence the variation of the values of any of the psychophysical variables evaluated (p > .05).

CONCLUSIONS

There is not a significant influence of impairment clusters based on psychological variables and sleep quality on painful mechanical sensitivity and pain modulation, regardless of the presence of TMD.

CLINICAL RELEVANCE

This outcome suggests that psychosocial factors and sleep quality may not play a decisive role in the sensory-discriminative aspect of pain, particularly concerning painful TMD.

Prediction of duloxetine efficacy in addition to self-management in painful temporomandibular disorders: A randomised, placebo-controlled clinical trial

BACKGROUND

Conditioned pain modulation (CPM) is a potential predictor of treatment response that has not been studied in temporomandibular disorders (TMD).

OBJECTIVES

We conducted a randomised, double-blind, placebo-controlled trial (RCT) of duloxetine in addition to self-management (SM) strategies to investigate its efficacy to reduce pain intensity in painful TMD patients. Moreover, we investigated whether baseline CPM would predict the duloxetine efficacy to reduce TMD pain intensity.

METHODS

Eighty participants were randomised to duloxetine 60 mg or placebo for 12 weeks. The primary outcomes were the change in the pain intensity from baseline to week-12 and CPM-sequential paradigm at baseline. Safety, physical and emotional functioning outcomes were also evaluated.

RESULTS

Of 80 participants randomised, 78 were included in intention-to-treat analysis. Pain intensity decreased for SM-duloxetine and SM-placebo but did not differ between groups (p = .82). A more efficient CPM was associated with a greater pain intensity reduction regardless of the treatment group (p = .035). Physical and emotional functioning did not differ between groups, but adverse events (p = .014), sleep impairment (p = .003) and catastrophizing symptoms (p = .001) were more prevalent in SM-duloxetine group.

CONCLUSION

This study failed to provide evidence of a beneficial effect of adding duloxetine to SM strategies for treatment of painful TMD. Nonetheless, this RCT has shown the feasibility of applying pain modulation assessment to predict short-term treatment response in painful TMD patients, which confirms previous finds that CPM evaluation may serve a step forward in individualising pain treatment.

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.

Divergence between confidence and knowledge of endodontists regarding non-odontogenic pain

INTRODUCTION

This study aimed to assess the self-reported levels of confidence and knowledge related to non-odontogenic pain among a group of Brazilian endodontists.

METHODOLOGY

A total of one hundred and forty-six endodontists affiliated with the Brazilian Society of Endodontics participated in the survey. The questionnaire, distributed via email or WhatsApp, contained inquiries designed to gauge self-perceived confidence and knowledge concerning non-odontogenic pain. The practitioners were categorized into four groups based on their self-reported familiarity with various orofacial pain types, classified as either sufficient or insufficient, and on their engagement in ongoing educational programs related to orofacial pain. Data were analyzed by Chi-Square Test and Fischer's exact test (p<0.05).

RESULTS

Overall, self-reported confidence about non-odontogenic pain was high, especially for endodontists who considered their knowledge about orofacial pain sufficient, regardless of whether they had (71.1% - 97.8%) or not (35.7% - 96.4%) been continuously involved in education courses on orofacial pain. In general, self-reported knowledge about non-odontogenic pain was insufficient (0% - 42%), except in the question about how they would act in cases of pain that persists beyond the normal healing time after an endodontic procedure (70.6% - 81.9%). In general, endodontists are confident in their diagnosis and treatment of non-odontogenic pain. Nonetheless, this confidence did not correlate with a commensurate knowledge depth of. Thus, specialization courses in endodontics should highly consider training and qualifying these professionals in the diagnosis of non-odontogenic pain.

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

STATEMENT OF PROBLEM

The relationship of awake bruxism with pain is still unclear.

PURPOSE

The 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 METHODS

A 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).

RESULTS

Overall 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).

CONCLUSIONS

The most prevalent behavior was tooth contact (29.4%). No relationship was found between awake bruxism behaviors and masticatory muscle tenderness or endogenous analgesia.

Ecological Momentary Assessment of Awake Bruxism Behaviors: A Scoping Review of Findings from Smartphone-Based Studies in Healthy Young Adults

BACKGROUND

The recent introduction of ecological momentary assessment (EMA) smartphone-based strategies has allowed achieving some interesting data on the frequency of different awake bruxism (AB) behaviors reported by an individual in the natural environment.

OBJECTIVE

The present paper aims to review the literature on the reported frequency of AB based on data gathered via smartphone EMA technology.

METHODS

On September 2022, a systematic search in the Pubmed, Scopus and Google Scholar databases was performed to identify all peer-reviewed English-language studies assessing awake bruxism behaviors using a smartphone-based Ecological Momentary Assessment. The selected articles were assessed independently by two authors according to a structured reading of the articles' format (PICO).

RESULTS

A literature search, for which the search terms "Awake Bruxism" and "Ecological Momentary Assessment" were used, identified 15 articles. Of them, eight fulfilled the inclusion criteria. The results of seven studies using the same smartphone-based app reported a frequency of AB behaviors in the range between 28.3 and 40% over one week, while another investigation adopted a different smartphone-based EMA approach via WhatsApp using a web-based survey program and reported an AB frequency of 58.6%. Most included studies were based on convenience samples with limited age range, highlighting the need for more studies on other population samples.

CONCLUSIONS

Despite the methodological limits, the results of the reviewed studies provide a standpoint for comparison for future studies on the epidemiology of awake bruxism behaviors.

Catastrophizing and Hypervigilance Influence Subjective Sleep Quality in Painful TMD Patients

Aims: To determine sleep quality and associated factors in a group of patients with painful TMDs. Methods: The medical records of 80 patients with arthralgia and/or myofascial pain were reviewed and compared to a healthy control group. Data about sex, age, subjective pain, physical activity, social activity, subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), pain vigilance (Pain Vigilance and Awareness Questionnaire [PVAQ]), and pain catastrophizing (Pain Catastrophizing Scale [PCS]) were collected. Relationships between PSQI, age, pain intensity, PVAQ, and PCS in the TMD group were also analyzed. Data from the control group were used to transform the PSQI results into T-scores, which were then used to divide the TMD group into two subgroups: normal and impaired sleep. Results: TMD patients presented a significantly higher (P < .001) PSQI score than the control group. Also, in the TMD group, there was a low to moderate correlation between PSQI and pain intensity and a significant correlation between PVAQ and PCS. The impaired sleep group presented a significantly higher (P < .001) PSQI T-score than the normal sleep group. Univariate analysis showed that subjective pain, social activity, and the PCS total and subscale scores differed significantly between the different PSQI T-score groups. The comparison between TMD pain patients and control subjects showed a significantly higher prevalence of T-score discordance in almost all PSQI components in TMD patients with impaired sleep. Conclusion: Subjective sleep quality in painful TMD patients could be associated with and influenced by psychosocial factors (catastrophizing and hypervigilance), social activity, and pain intensity.

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, IL1β +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.

Primary headache and myofascial pain: a data based study

Aim: This study aimed to evaluate the relationship between the presence of primary headaches and myofascial pain in orofacial patients. Materials and methods: Six hundred and ninety-nine records of patients seeking treatment in a specialized orofacial pain clinic were assessed. The primary diagnostic categories of headache and myofascial pain were recorded. Data analyses were carried out by Pearson Chi-square and Logistic Regression, with a p-value of 0.05. Results:  Average age of patients was 34.6 years. Females constituted 82.8% of the sample. A relationship between the presence of tension-type headache and myofascial pain was found (p=0.00); however, this relationship was not found for the presence of migraine and myofascial pain (p>0.05). Discussion: Tension-type headaches may be triggered or perpetuated by trigger points in orofacial structures. Conclusion: It can be concluded that trigger points in myofascial pain patients can play an important role in the genesis of tension-type headache.

Effects of Botulinum Toxin Type A on the Psychosocial Features of Myofascial Pain TMD Subjects: A Randomized Controlled Trial

AIMS

To determine the effects of botulinum toxin type A (BoNT-A) on the psychosocial features of patients with masticatory myofascial pain (MFP).

METHODS

A total of 100 female subjects diagnosed with MFP were randomly assigned into five groups (n = 20 each): oral appliance (OA); saline solution (SS); and three groups with different doses of BoNT-A. Chronic pain-related disability and depressive and somatic symptoms were evaluated with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II instruments at baseline and after 6 months of treatment. Differences in treatment effects within and between groups were compared using chi-square test, and Characteristic Pain Intensity (CPI) was compared using two-way ANOVA. A 5% probability level was considered significant in all tests.

RESULTS

Most patients presented low pain-related disability (58%), and 6% presented severely limiting, high pain-related disability. Severe depressive and somatic symptoms were found in 61% and 65% of patients, respectively. In the within-group comparison, BoNT-A and OA significantly improved (P < .001) scores of pain-related disability and depressive and somatic symptoms after 6 months. Only the scores for pain-related disability changed significantly over time in the SS group. In the between-group comparison, BoNT-A and OA significantly improved (P < .05) scores of all variables at the final follow-up when compared to the SS group. No significant difference was found between the BoNT-A and OA groups (P > .05) for all assessed variables over time.

CONCLUSION

BoNT-A was at least as effective as OA in improving pain-related disability and depressive and somatic symptoms in patients with masticatory MFP.

The hierarchy of different treatments for myogenous temporomandibular disorders: a systematic review and network meta-analysis of randomized clinical trials

The best treatment modality for the management of painful temporomandibular disorders of muscular origin (M-TMD) with predictable outcomes based on solid evidence is still not well defined. Thus, the aim of this network meta-analysis (NMA) was to identify the best treatment for adult patients with M-TMD. An electronic search was undertaken from the inception of each database to August 2018, to identify randomized clinical trials (RCTs), which are comparing two or more of the following treatment modalities in patients with M-TMD: counseling therapy; occlusal appliances; manual therapy; laser therapy; dry needling; intramuscular injection of local anesthesia (LA) or botulinum toxin-A (BTX-A); muscle relaxants; hypnosis/relaxation therapy; oxidative ozone therapy; and placebo or no treatment. Primary outcome variables were the reduction of pain and mechanical sensitivity. The secondary outcome was the maximal mouth opening (MMO). The quality of evidence was rated according to Cochrane's tool for assessing risk of bias. Standardized mean difference was used to analyze via frequentist network meta-analysis (NMA), using STATA software. 52 RCTs were included in this NMA. At the most follow up moments, manual therapy, counseling therapy, occlusal splints therapy, and needling using BTX-A or LA as well as dry needling significantly decreased post-treatment pain intensity in M-TMDs, when compared to placebo.  At short term (≤5 months), the four highest-ranked treatments for post-treatment pain reduction were manual therapy (83.5%, low quality evidence), ozone therapy (75.7%, very low quality evidence),counseling  therapy (71.2%, moderate quality), and occlusal appliances  (71.7%,moderate quality evidence). When intermediate term (≥6 months)was considered, BTX-A (85.8%, very low quality evidence) , counseling therapy(80%, low quality evidence), occlusal appliances  (62.8%, low quality evidence) and hypnosis (50.6%, very low quality evidence) were the four highest-ranked treatments.  This NMA reveals that manual therapy can be considered the most effective treatment for M-TMD, followed by counseling treatment, intramuscular injection of LA, and occlusal appliances  . However, considering the limitations of the studies included, and the scarce of strong evidence, the present findings should be interpreted cautiously.

COVID-19 pandemic impact on headache in healthcare workers: a narrative review

Background: Pandemic of COVID-19, the potentially fatal disease caused by SARS-CoV-2, had caused intangible consequences on global health systems, economy, daily life, education, travel, leisure, work, and mental health. Its impact on mental and physical health, especially in health professionals, has been described. Objective: This study aimed to review and discuss the published evidence regarding the presence of headache on COVID-19 healthcare workers. Methods: In this review, we searched for all articles published in various data bases including PubMed / Medline, Scopus, and Web of Science and all original research studies, letters to editor, case reports, commentaries and reviews published in English, Portuguese or Spanish were searched. Two researchers independently analyzed published articles in order to include/exclude based on inclusion or exclusion criteria.  Results: Thirteen articles were included.  All studies included in this review were observational; eleven were cross-sectional studies, one was a prospective/cohort and one was a retrospective. Two studies evaluated psychological outcomes, mental health disorders and associated factors, one study investigated symptoms and causes of somatic symptom disorder and all other studies evaluated headaches associated with Personal Protective Equipment (PPI). Conclusions: The present review shows that COVID-19 pandemic has negative impact on physical and mental health in healthcare workers and headache has been associated to psychological stress and work overload during pandemic.  Further studies are necessary to better investigate COVID-19 pandemic effects on headaches and other neurological conditions.

Oral behaviors, bruxism, malocclusion and painful temporomandibular joint clicking: is there an association?

The present cross-sectional case-control study aimed to determine if there is an association between specific oral behaviors, sleep bruxism (SB), awake bruxism (AB), and painful temporomandibular joint (TMJ) clicking. Ninety individuals were dived into three groups; Group 1 (n = 30): painful TMJ clicking; Group 2 (n = 30): painless TMJ clicking; and Group 3 (n = 30): control group. The following clinical data were studied: oral behaviors (unilateral chewing, gum chewing, nail biting, foreign objects biting, leaning with jaw against the hand, and sleeping in a position that pressures the jaw), SB, AB (including the frequency in 10 days, evaluated by ecological momentary assessment), and malocclusions investigated based on clinical inspections (anterior open bite, posterior cross-bite, abnormal overbite/overjet, occlusal guidance, mediotrusive and/or laterotrusive interferences, retruded contact position to maximum intercuspation slide, missing posterior teeth). All statistical tests (Kolmogorov-Smirnov, chi-square, and one-way ANOVA) were performed with a 5% significance level. Group 1 had the highest frequency of and a significant association with leaning with jaw in the hand, sleeping position that pressures the jaw, gum chewing, nail biting, and AB (p<0.05). Gum chewing, nail biting, and AB were associated with Group 2 only when compared to Group 3 (p<0.05). No significant difference among groups was found for other behaviors (unilateral chewing and foreign objects biting), SB, and all malocclusions (p>0.05). It can be concluded that patients with painful TMJ clicking had a higher frequency of and a significant association with some specific harmful behaviors and AB.

Association of sleep quality and psychological aspects with reports of bruxism and TMD in Brazilian dentists during the COVID-19 pandemic

BACKGROUND

Dentists are exposed to contamination by SARS-CoV-2 due to dental interventions, leading to a state of alert and potential risk of negative impact in mental health and sleep quality, associated with Temporomandibular Disorder (TMD) and bruxism.

OBJECTIVE

to evaluate the psychosocial status, sleep quality, symptoms of TMD, and bruxism in Brazilian dentists (DSs) during the COVID-19 pandemic.

METHODOLOGY

The sample (n=641 DSs) was divided into three groups (quarantined DSs; DSs in outpatient care; and frontline professionals), which answered an electronic form containing the TMD Pain Screening Questionnaire (Diagnostic Criteria for Temporomandibular Disorders - DC/TMD), the Pittsburgh Sleep Quality Index (PSQI), the Depression, Anxiety and Stress Scale (DASS-21), and the sleep and awake bruxism questionnaire. ANOVA test and Mann Whitney post-test were used, with Bonferroni adjustment (p<0.016) and a 95% confidence level.

RESULTS

Probable TMD was found in 24.3% (n=156) of the participants, while possible sleep and awake bruxism were diagnosed in 58% (n=372) and 53.8% (n=345) of them, respectively. Among all variables evaluated, only symptoms of depression were significantly greater in the quarantined DSs group when compared to those who were working at the clinical care (p=0.002). Working DSs were significantly less likely (OR=0.630, p=0.001) to have depressive symptoms. Those who were not worried or less worried about the pandemic were less likely to experience stress (OR=0.360), anxiety (OR=0.255), and poor sleep quality (OR=0.256). Sleep had a strong positive and moderate correlation with psychological factors on frontline workers and DSs in outpatient care, respectively.

CONCLUSION

The results suggest confinement may have a more negative impact on the life of DSs than the act of being actively working. The concern about Covid-19 and poor sleep quality was significantly prevalent and may negatively affect the quality of life of DSs. Thus, further research on the topic is needed.

Botulinum toxin type A and acupuncture for masticatory myofascial pain: a randomized clinical trial

BoNT-A has been widely used for TMD therapy. However, the potential benefits compared to dry needling techniques are not clear.

Effects of acute mental stress on conditioned pain modulation in temporomandibular disorders patients and healthy individuals

Stress is a contributing factor to painful temporomandibular disorders (TMD). Nevertheless, the underpinnings of this relationship are not fully understood.

Cutaneous allodynia in patients with atypical odontalgia

Short Communication

Can Concomitant Masticatory Muscle Contraction Interfere with Temporomandibular Joint Arthralgia Evaluation?

AIMS

To investigate the effect of masticatory muscle contraction on the pressure pain threshold (PPT) of the lateral pole of the temporomandibular joint (TMJ) in patients with TMJ arthralgia and in asymptomatic individuals.

METHODS

A total of 72 individuals divided into two groups (group 1: patients with unilateral TMJ arthralgia [n = 36]; group 2: control group, asymptomatic individuals [n = 36]) were compared. The PPT of the lateral pole of the TMJ with and without concomitant masticatory muscle contraction was determined using a digital algometer in both groups. Paired and independent Student t test were used to compare the data within and between groups, respectively. A 5% significance level was used for all tests.

RESULTS

Higher TMJ PPT values with concomitant masticatory muscle contraction were found in both groups (P < .001). The amount of increase in PPT with contracted muscles was not significantly different between groups (P = .341), but the TMJ arthralgia group had significantly lower PPT values than the control group regardless of muscle contraction status (P < .001).

CONCLUSION

Concomitant masticatory muscle contraction significantly increased the PPT of the lateral pole of the TMJ in relation to relaxed muscles, regardless of the presence of arthralgia.

Effect of Genetic Polymorphisms on Pain Sensitivity in the Orofacial Region: A Systematic Review

AIMS

To systematically review the literature to assess whether genetic polymorphisms affect orofacial pain sensitivity in healthy individuals and in patients with chronic orofacial pain disorders.

METHODS

Electronic searches were conducted to identify observational studies and clinical trials investigating the association between genetic polymorphisms and orofacial pain sensitivity in healthy individuals and/or patients with chronic orofacial pain disorders. Searches were carried out in PubMed, Embase, and Scopus databases using Medical Subject Headings and free terms.

RESULTS

Seven studies fulfilled the eligibility criteria: four analyzed healthy subjects, two included chronic orofacial pain patients, and one included samples of healthy subjects and patients with neuropathic pain. The results showed that genes associated with mechanical and thermal pain sensitivity were mostly related to opioid, catecholaminergic, inflammatory, and dopaminergic pathways.

CONCLUSION

Genetic polymorphisms related to opioid, catecholaminergic, inflammatory, and dopaminergic pathways were associated with sensitivity to thermal and pressure stimuli in the orofacial region. Therefore, genetic factors should be taken into account for an accurate interpretation of orofacial pain sensitivity. These results will allow for a better understanding of the etiopathogenesis of chronic pain affecting the orofacial region, and consequently for finding new therapeutic targets.

Audiological Evaluation of Patients With Somatosensory Tinnitus Attributed to Temporomandibular Disorders

Purpose Tinnitus and temporomandibular disorders have already been associated in the literature, but despite many studies, it is still an intriguing discussion point. This study aimed to evaluate the prevalence of hearing loss among somatosensory tinnitus patients with temporomandibular disorders and to assess the influence of tinnitus on patients' quality of life. Method An otolaryngologist examined 585 patients in order to detect and evaluate the presence of tinnitus. Subjects were evaluated using the Portuguese version of the Research Diagnostic Criteria for Temporomandibular Disorders. An analysis of the somatic component of tinnitus was performed. Tinnitus was rated according to its onset (at least 6 months) and intensity with a visual analog scale. The sample was composed of 100 patients with somatosensory tinnitus divided into two groups: Group 1 (with temporomandibular disorder, n = 85) and Group 2 (without temporomandibular disorder, n = 15). The audiological evaluation was composed of pure-tone audiometry, high-frequency audiometry, tympanometry, and transient-evoked otoacoustic emissions. The impact of tinnitus on quality of life was assessed by the Tinnitus Handicap Inventory adapted and validated to Portuguese language. Results Pure-tone audiometry did not differ with statistical significance between groups (p = .29), neither did the high-frequency audiometry results (p = .74). Tinnitus Handicap Inventory scores also did not show any differences between Groups 1 and 2 (p = .67). Conclusions Subjects with somatosensory tinnitus, who also have temporomandibular disorders, do not seem to have hearing impairment. Also, they do not have a higher quality of life handicap when compared to those without tinnitus and temporomandibular disorder.

Clinical variables associated with the presence of articular pain in patients with temporomandibular joint clicking

OBJECTIVE

To study and estimate the impact of clinical, somatosensory, and psychosocial variables associated with the concomitant presence of temporomandibular joint (TMJ) pain in patients with TMJ clicking.

MATERIALS AND METHODS

Ninety-three individuals composed the sample: patients with painful TMJ clicking (n = 47) and patients with painless TMJ clicking (n = 46). Four categories of data were evaluated: clinical features (gender, maximal interincisal distance (MID), side of complaint, age); bruxism (sleep bruxism (SB), awake bruxism (AB)); somatosensory (mechanical pain threshold (MPT), wind-up ratio (WUR), pressure pain threshold (PPT), conditioned pain modulation (CPM)); and psychosocial (Pittsburgh Sleep Quality Index (PSQI), pain vigilance and awareness questionnaire (PVAQ), Pain Catastrophizing Scale (PCS), Tampa Scale for Kinesiophobia for Temporomandibular Disorders (TSK/TMD), Oral Behaviors (OBs)).

RESULTS

Female gender, AB, WUR, CPM, PSQI, PCS, and OBs significantly (p < 0.05) increased the chance of the concomitant presence of TMJ pain in patients with TMJ clicking. On the other hand, MID, MPT, and PPT significantly (p < 0.05) decreased this chance. The other variables had no association.

CONCLUSION

It can be concluded that being a woman, having AB, hyperalgesia in WUR, less efficient CPM, poor sleep quality, pain catastrophizing, and harmful OBs significantly increased the chance of the concomitant presence of TMJ pain in patients with TMJ clicking. In the opposite, high figures of MID, MPT, and PPT decreased the chance.

CLINICAL RELEVANCE

Most patients with TMJ clicking usually postpone seeking treatment until the clicking truly disturbs or there is a concomitant presence of TMJ pain. Understanding the variables associated with this concomitance can be important in clinical practice.

Insights for temporomandibular disorders management: From psychosocial factors to genetics-A case report

AIMS

This case report aimed to discuss the multifactorial etiology and also the management of temporomandibular disorders (TMD) by addressing important associated psychosocial and biological factors, emphasizing the interaction between these factors and a probable genetic predisposition.

METHODS AND RESULTS

A 21-year-old female patient was evaluated according to Research Diagnostic Criteria for TMD and diagnosed with arthralgia, myofascial pain, disc displacement without reduction, and temporomandibular joint (TMJ) degenerative disease. TMJ alterations were confirmed through magnetic resonance imaging and cone-beam computed tomography. Pressure pain threshold of masticatory structures was evaluated using a pressure algometer. Sleep bruxism, poor sleep quality, migraine with aura, mild anxiety, and history of facial trauma were also identified through anamnesis and clinical examination. Following this, genetic analysis was performed to evaluate the presence of single nucleotide polymorphisms (SNPs) already associated with TMD: SNP COMT Val¹⁵⁸ Met (rs4680), MMP1-1607 (rs1799750), and tumor necrosis factor alpha-308 (rs1800629), which were all present. A personalized treatment for TMD management was performed, and it included self-management programs, occlusal appliance therapy, pharmacotherapy, anxiety management, and stress control. An 8-year follow-up demonstrated long-term stabilization of TMJ degenerative disease.

CONCLUSION

Genetic evaluation, added to anamnesis and clinical examination, could be useful for TMD prognosis and management.

Pain complications of oral implants: Is that an issue?

The use of oral implants as a form of replacing missing teeth in partial or total edentulous patients is considered the gold standard in oral rehabilitation. Although considered a history of success in contemporary dentistry, surgical complications may occur, as excessive bleeding, damage to the adjacent teeth and mandibular fractures. Persistent pain and abnormal somatosensory responses after the surgery ordinary healing time are also potential problems and may lead to the development of a condition named posttraumatic trigeminal neuropathic pain (PTNP). Though relatively rare, PTNP has a profound impact on patient's quality of life. Appropriated previous image techniques, effective anaesthetic procedures and caution during the surgical procedure and implant installation are recommended for the prevention of this condition. In case of the PTNP, different management modalities, including antidepressant and membrane stabilizer medications, as well as peripheral strategies, as the use of topical medication and the botulin toxin are presented and discussed.

Evaluation of pain intensity in patients treated with aligners and conventional fixed appliances: Randomized clinical trial

OBJECTIVE

This randomized clinical trial aimed to compare the pain intensity in patients treated with orthodontic aligners and conventional fixed appliances.

SETTING AND SAMPLE POPULATION

This study was a randomized clinical trial. The sample comprised 39 patients randomly allocated into 2 groups: OA (orthodontic aligners, n = 20) and FA (Fixed Appliance, n = 19).

MATERIAL AND METHODS

The pain intensity was measured by the visual analogue scale (VAS) in the following periods: T0 (baseline), T1 (seven days after appliance placement) and seven days after each return on the first (T2), third (T3) and sixth (T4) months. The following variables were also investigated in the baseline: conditioned pain modulation, anxiety levels, hypervigilance and catastrophizing. The VAS measurements between groups were compared by the Mann-Whitney test. Comparisons between periods within each group were performed by the Friedman test. Data regarding catastrophizing and hypervigilance were compared by the t test. All tests were applied at a significance level of 5%, with 95% confidence interval.

RESULTS

Both groups presented similar levels of anxiety, hypervigilance, catastrophizing and conditioned pain modulation. Both groups did not differ concerning the pain intensity in all periods. The intragroup evaluation revealed statistical differences between days in the FA group at all moments evaluated, for the OA group, similar findings between days were found for the T1 evaluation; however, at the 6-month period (T4), the pain levels varied over these days without statistical difference. Higher levels of pain were observed in the first seven days after appliance placement.

CONCLUSION

The pain intensity, usually mild, was not influenced by the appliance design, although different patterns of reported pain seem to occur between groups.

Role of inflammatory and pain genes polymorphisms in temporomandibular disorder and pressure pain sensitivity

OBJECTIVE

The aim of this study was to assess the correlation of inflammatory and pain genes polymorphisms with the presence of temporomandibular disorder (TMD) patients and with pressure pain sensitivity.

DESIGN

Data was collected from 268 consecutive subjects at Bauru School of Dentistry. Subjects aged younger than 20 years, with dental and neuropathic pain, sinusitis, cognitive and neurologic disorder were excluded. Included subjects were evaluated using the Research Diagnostic Criteria for Temporomandibular disorders and divided into two groups: TMD cases and healthy controls. Groups were submitted to pressure pain threshold (PPT) test for the temporomandibular joint, anterior temporalis and masseter muscles and genotyped for Val158Met, IL6-174, IL-1β-3954 and TNFA-308. Student's t-test and Pearson chi-square test were used to comparisons between groups. A linear multiple regression was used to evaluate the influence of genetics variables on the PPT and a bivariate analysis was used to assesses the influence of genetics variables on pain sensitivity below the PPT cut off of the structures in TMD group.

RESULTS

TMD group showed significantly lower PPT values for all structures when compared with control group (p < 0.001). SNP IL6-174 predicted higher pain sensitivity in the temporomandibular joint (p < 0.005) and in anterior temporalis muscle (p < 0.044) and SNP Val158Met in the masseter muscle (p < 0.038); when TMD group was divided according to PPT cut-off values the SNP Val158Met influenced increase pain sensibility in the masseter muscle.

CONCLUSION

TNFA-308 was associated with TMD and SNP IL6-174 and SNP Val158Met influenced pain sensitivity of patients with TMD.

Influence of self-reported physical activity and sleep quality on conditioned pain modulation in the orofacial region

OBJECTIVES

To evaluate the influence of self-reported physical activity and sleep quality on conditioned pain modulation (CPM) in the orofacial region.

MATERIALS AND METHODS

Ninety healthy participants aged 18-50 years old were evenly distributed according to the level of physical activity into low, moderate, and high level. The classification of physical activity was based on modified criteria of the International Physical Activity Questionnaire (IPAQ), considering intensity, duration, and frequency of physical activity. The Pittsburgh Sleep Quality Index (PSQI) assessed sleep quality and the individuals were then classified as good or poor sleepers. CPM was assessed using the pressure pain threshold (PPT) of the anterior temporalis as test stimulus and hand immersion in hot water as conditioning stimulus. ANOVA was applied to the data and Tukey's posttest was applied when the main effects or interactions were significant (p < 0.050).

RESULTS

There was no significant main effect of neither physical activity nor sleep quality on pain modulation. However, individuals who reported high level of physical activity and good quality of sleep had a greater pain modulation (- 0.60 ± 0.34) when compared with those who reported moderate (- 0.10 ± 0.25) and low level of physical activity (- 0.10 ± 0.52) and good sleep quality (p < 0.028).

CONCLUSIONS

Pain modulation seems to be more efficient in individuals who report a good sleep quality and a high level of physical activity.

CLINICAL RELEVANCE

Conditioned pain modulation is highly variable in healthy people. Therefore, a multifactorial approach should be taken into consideration in the evaluation of the efficacy of endogenous analgesia.

The association of self-reported awake bruxism with anxiety, depression, pain threshold at pressure, pain vigilance, and quality of life in patients undergoing orthodontic treatment

This study aimed to evaluate whether the presence of awake bruxism was associated with temporomandibular dysfunction symptoms, pain threshold at pressure, pain vigilance, oral health-related quality of life (OHRQoL), and anxiety and depression symptoms in patients undergoing orthodontic treatment.

Placebo and nocebo response magnitude on temporomandibular disorder-related pain: A systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review (SR) was to answer the following question: "In adult patients with temporomandibular disorder (TMD)-related pain, what is the placebo or nocebo effect of different therapies?"

METHODS

A SR was performed with randomised clinical placebo-controlled trials on diagnosed painful TMD studies from five main databases and from three grey literature. Studies included must have sample older than 18 years, with painful TMD, which diagnosis was done by Research Diagnostic Criteria (RDC/TMD) or Diagnostic Criteria (DC/TMD).

RESULTS

Out of 770 articles obtained, 42 met the inclusion criteria for qualitative and 26 for quantitative analysis. Meta-analysis indicated mean variation on pain intensity for placebo therapy was higher on laser acupuncture with 45.5 mm point reduction, followed by avocado soya bean extract with 36 mm and amitriptyline 25 mg with 25.2 mm. Laser showed a 29% of placebo effect, as well medicine with 19% and other therapies with 26%. Possible nocebo effect of 8% pain increase was found for intra-articular injection of Ultracain.

CONCLUSIONS

Based on the available data, the placebo response could play a major effect on TMD pain management and may be responsible from 10% to 75% of pain relief. Laser acupuncture, avocado soya bean and amitriptyline promoted the higher placebo effect. Possible nocebo effect was found only for Ultracain injection with 8%.

CLINICAL RELEVANCE

Clinicians could apply such evidence to optimise pain management and judgement about treatment efficacy, and researches may find it useful when designing their investigations.

Temporomandibular joint morphology does not influence the presence of arthralgia in patients with disk displacement with reduction: a magnetic resonance imaging-based study

OBJECTIVE

The aim of this study was to compare, by using magnetic resonance imaging (MRI), temporomandibular joint (TMJ) morphology between patients with disk displacement with reduction (DDWR) with or without arthralgia and a control group and to identify which factors are associated with the concomitant presence of arthralgia in DDWR patients.

STUDY DESIGN

In this investigation, 36 TMJ MRIs were divided into 3 groups. Group 1 (n = 12) comprised patients with DDWR and arthralgia; group 2 (n = 12) comprised patients with DDWR without arthralgia; and group 3 (n = 12) was the control group. Disk and mandibular condyle morphologies; articular eminence morphology and inclination; size of the mandibular fossa; joint space size; joint effusion; bone marrow of the mandibular condyle; and the relative signal intensity of retrodiscal tissue were evaluated.

RESULTS

Fisher's exact test and 1-way analysis of variance (ANOVA) revealed no significant differences (P > .05) between groups for any variable. Logistic regression analysis showed that no anatomic variables were related to the concomitant presence of arthralgia in patients with DDWR (P > .05).

CONCLUSIONS

As evaluated on MRI scans, no significant differences in the anatomic characteristics of the TMJ were detected between DDWR patients with or without concomitant arthralgia and the control group. There were no factors associated with the concomitant presence of arthralgia in patients with DDWR.

Temporomandibular joint disc displacement with reduction: a review of mechanisms and clinical presentation

Disc displacement with reduction (DDWR) is one of the most common intra-articular disorders of the temporomandibular joint (TMJ). Factors related to the etiology, progression and treatment of such condition is still a subject of discussion. This literature review aimed to address etiology, development, related factors, diagnosis, natural course, and treatment of DDWR. A non-systematic search was conducted within PubMed, Scopus, SciELO, Medline, LILACS and Science Direct using the Medical Subjective Headings (MeSH) terms “temporomandibular disorders”, “temporomandibular joint”, “disc displacement” and “disc displacement with reduction”. No time restriction was applied. Literature reviews, systematic reviews, meta-analysis and clinical trials were included. DDWR is usually asymptomatic and requires no treatment, since the TMJ structures adapt very well and painlessly to different disc positions. Yet, long-term studies have shown the favorable progression of this condition, with no pain and/or jaw locking occurring in most of the patients.

Distribution of depression, somatization and pain-related impairment in patients with chronic temporomandibular disorders

Objective

the aim of this study was to describe the frequency of psychosocial diagnoses in a large sample of patients attending a tertiary clinic for treatment of temporomandibular disorders (TMD).

Material and Methods

six hundred and ninety-one patients who sought treatment for pain-related TMD were selected. Chronic pain-related disability (Graded Chronic Pain Scale, GCPS), depression [Symptoms Checklist-90 (SCL-90) scale for depression, DEP] and somatization levels (SCL-90 scale for non-specific physical symptoms, SOM) were evaluated through the Research Diagnostic Criteria for TMD (RDC/TMD) Axis II psychosocial assessment; TMD diagnoses were based on the Axis I criteria.

Results

the majority of patients presented a low disability or no disability at all, with only a small portion of individuals showing a severely limiting, high disability pain-related impairment (4.3%). On the other hand, abnormal scores of depression and somatization were high, with almost half of the individuals having moderate-to-severe levels of depression and three-fourths presenting moderate-to-severe levels of somatization. The prevalence of high pain-related disability (GCPS grades III or IV), severe/moderate depression and somatization was 14.3%, 44% and 74.1% respectively. Gender differences in scores of SCL-DEP (p=0.031) and SCL-SOM (p=0.001) scales were signficant, with females presenting the highest percentage of abnormal values.

Conclusion

patients with TMD frequently present an emotional profile with low disability, high intensity pain-related impairment, and high to moderate levels of somatization and depression. Therefore, given the importance of psychosocial issues at the prognostic level, it is recommended that clinical trials on TMD treatment include an evaluation of patients’ psychosocial profiles.

Muscle hardness and masticatory myofascial pain: Assessment and clinical relevance

The impression of increased muscle hardness in painful muscles is commonly reported in the clinical practice but may be difficult to assess. Therefore, the aim of this review was to present and discuss relevant aspects regarding the assessment of muscle hardness and its association with myofascial temporomandibular disorder (TMD) pain. A non-systematic search for studies of muscle hardness assessment in patients with pain-related TMDs was carried out in PubMed, Cochrane Library, Embase and Google Scholar. Mechanical devices and ultrasound imaging (strain and shear wave elastography) have been consistently used to measure masticatory muscle hardness, although an undisputable reference standard is yet to be determined. Strain elastography has identified greater masseter hardness of the symptomatic side in patients with unilateral myofascial TMD pain when compared to the contralateral side and healthy controls (HC). Likewise, shear wave elastography has shown greater masseter elasticity modulus in patients with myofascial TMD pain when compared to HC, which may be an indication of muscle hardness. Although assessment bias could partly explain these preliminary findings, future randomised controlled trials are encouraged to investigate this relationship. This qualitative review indicates that the muscle hardness of masticatory muscles is still a rather unexplored field of investigation with a good potential to improve the assessment and potentially also the management of myofascial TMD pain. Nonetheless, the current evidence in favour of increased hardness in masticatory muscles in patients with myofascial TMD pain is weak, and the pathophysiological importance and clinical usefulness of such information remain unclear.

Short-term transcutaneous electrical nerve stimulation reduces pain and improves the masticatory muscle activity in temporomandibular disorder patients: a randomized controlled trial

Studies to assess the effects of therapies on pain and masticatory muscle function are scarce.

The mobility of the upper cervical spine by flexion-rotation test in individuals with temporomandibular dysfunction

Short Communication

Occlusal changes secondary to temporomandibular joint conditions: a critical review and implications for clinical practice

The relationship between Temporomandibular Disorders (TMD) and malocclusion is an extremely critical issue in dentistry. Contrary to the old concept that malocclusion causes TMD, occlusal changes, especially those observed as sudden, may be secondary and reflect joint or muscle disorders due to the obvious connection between these structures and the dental occlusion.

TMD and chronic pain: a current view

This review aims at presenting a current view on the physiopathologic mechanisms associated with temporomandibular disorders (TMDs). While joint pain is characterized by a well-defined inflammatory process mediated by tumor necrosis factor-α and interleukin, chronic muscle pain presents with enigmatic physiopathologic mechanisms, being considered a functional pain syndrome similar to fibromyalgia, irritable bowel syndrome, interstitial cystitis and chronic fatigue syndrome. Central sensitization is the common factor unifying these conditions, and may be influenced by the autonomic nervous system and genetic polymorphisms. Thus, TMDs symptoms should be understood as a complex response which might get worse or improve depending on an individual's adaptation.

Is the Nociceptive Blink Reflex Associated with Psychological Factors in Healthy Participants?

AIMS

To evaluate the possible association between the nociceptive blink reflex (nBR) and various pain-related psychological measures: the Anxiety Sensitivity Index-3 (ASI-3), the Fear of Pain Questionnaire III (FPQ-III), the Pain Vigilance and Awareness Questionnaire (PVAQ), the Somatosensory Amplification Scale (SSAS), the Pain Catastrophizing Scale (PCS), and the Situational Pain Catastrophizing Scale (S-PCS).

METHODS

The nBR was evaluated in 21 healthy participants. It was elicited by a nociceptive-specific electrode placed over the entry zone of the right supraorbital nerve, infraorbital nerve, and mental nerve, as well as the left infraorbital nerve. The outcomes were (1) nBR measurements: (a) individual electrical sensory threshold (I0) and pain threshold (IP); (b) root mean square (RMS), area under the curve (AUC), and onset latencies of R2 responses; (c) stimulus-evoked pain on a 0 to 10 numeric rating scale (NRS); and (2) the ASI-3, the FPQ-III, the PVAQ, the SSAS, the PCS, and the S-PCS. Pearson correlation coefficient was used to evaluate the association between the means of nBR measurements from all sites and the questionnaires The significance level was set up after a Bonferroni correction (adjusted α = .8%).

RESULTS

There was no correlation for any pair of variables at the adjusted significance level (P > .008). There was only a single significant correlation at the standard significance level (P < .05), where the pain intensity (NRS) at 50% of IP presented a positive and small to moderate correlation with the PCS (r = 0.43, P = .04).

CONCLUSION

It appears that the nBR and its associated psychophysical measures are not associated with psychological factors in healthy participants.

The coexistence of paroxysmal hemicrania and temporomandibular disorder: importance of multidisciplinary approach

Paroxysmal hemicrania (PH) is a trigeminal autonomic cephalalgia, a rare primary headache characterized by unilateral periorbital and/or temporal attacks of severe intensity and short duration. In this situation, the determination of a correct diagnosis is crucial for the establishment of a proper management strategy. In the case of head and facial pain, this step is usually a big challenge since many conditions share the same features, as some primary headaches and temporomandibular disorders (TMD). The relationship between PH and TMD has not been determined. This paper describes a case of a female patient diagnosed with TMD and presenting concomitant headache attacks fulfilling the International Headache Society's criteria for PH. It is also emphasized the importance of dentist in this scenario, for many times responsible for the initial diagnosis of facial/head pain. Moreover, it is presented an integrated and simultaneously approach of both conditions, PH and TMD.

Headache Attributed to Masticatory Myofascial Pain: Clinical Features and Management Outcomes

AIMS

To describe the characteristics of headaches attributed to temporomandibular disorders (TMD) and assess the effects of two management strategies used for the management of TMD on headache intensity and frequency.

METHODS

The initial sample (n=60) of this randomized controlled trial comprised patients with masticatory myofascial pain according to the Research Diagnostic Criteria for TMD (RDC/TMD), and headache. The patients were divided into two groups: group 1 received only counseling for behavioral changes, and group 2 received counseling and an occlusal appliance. A 5-month follow-up period included three assessments. TMD-related headache characteristics, eg, headache intensity (scored on a visual analog scale [VAS]) and frequency were measured by a questionnaire. Two-way analysis of variance, chi-square, Friedman, and Mann-Whitney tests were used to test for differences considering a 5% significance level.

RESULTS

The main clinical features of headache attributed to masticatory myofascial pain were the long duration (≥4 hours), frontotemporal bilateral location, and a pressing/tightening quality. Forty-one subjects (group 1, 17 subjects; group 2, 24 subjects) were included in the final analysis. There was a reduction in headache intensity and frequency, with no significant differences between groups (P>.05). The mean (±SD) baseline VAS was 7.6 (±2.2) for group 1 and 6.5 (±1.6) for group 2; final values were 3.1 (±2.2) (P<.001) and 2.5 (±2.3) (P<.001), respectively.

CONCLUSION

Headache attributed to masticatory myofascial pain was mainly characterized by long duration, frontotemporal bilateral location, and a pressing/tightening quality. Also, counseling and behavioral management of masticatory myofascial pain improved headache, regardless of the use of an occlusal appliance.