Correlation of stress and muscle activity of patients with different degrees of temporomandibular disorder

Is There a Relationship between Salivary Cortisol and Temporomandibular Disorder: A Systematic Review

BACKGROUND

This systematic review examines and evaluates the relationship between salivary cortisol levels and temporomandibular disorder (TMD) in young adult patients.

METHOD

Six databases-PubMed, Scopus, Web of Science, Google Scholar, ProQuest, and Cochrane Library-were utilized to screen eligible studies. A systematic search was performed based on PECO questions and eligibility criteria. The research question for this review was "Do salivary cortisol levels correlate with TMD in individuals aged 18-40?" The risk of bias for quality assessment was determined by the Cochrane tool. PRISMA guidelines were followed while performing this review.

RESULT

A total of fourteen studies were included in this review. Of these, eleven were observational studies (four cross-sectional and seven case-control), and three were randomized control trials. Eleven of the included studies presented a low to moderate risk in the qualitative synthesis. The total sample size of the included studies was 751 participants. The included studies suggest higher salivary cortisol levels in TMD patients than in healthy individuals.

CONCLUSIONS

The findings of this review indicate higher salivary cortisol levels in adult patients with TMD than in healthy controls. Thus, supportive psychological treatment and clinical modalities should be provided to patients with TMD. Moreover, higher-quality studies with low heterogeneity are required to support this finding.

Pain and salivary biomarkers of stress in temperomandibular disorders were affected by maxillary splints

BACKGROUND

Longitudinal intervention studies on treatment options in temporomandibular dysfunction (TMD) including self reports and salivary biomarkers of stress are rare and the exact therapeutic function of occlusal splints widely unknown.

METHODS

We examined the therapeutic effects of a Michigan splint with occlusal relevance in patients with TMD using a placebo-controlled, delayed-start design. Two intervention groups received a Michigan splint, while one of them had a placebo palatine splint for the first 3 weeks. We collected pain intensities (at rest and after five occlusal movements), salivary measures associated with stress (cortisol and alpha-amylase) and self-reported psychological distress (stress, anxiety, catastrophizing) at baseline and 3 and 7 weeks after onset of intervention.

RESULTS

At baseline, we observed increased pain intensity and psychological distress in TMD patients compared to 11 matched healthy controls. Baseline anxiety was linked to movement pain intensity through stress. Over therapy reductions in pain intensity and morning cortisol were more pronounced in those patients starting immediately with the Michigan splint, while psychological distress decreased similarly in both groups.

CONCLUSION

Our results suggest that perceived stress plays a role for the association between anxiety and TMD pain and underlines the need for an interdisciplinary perspective on the pathogenesis and therapy of TMD in a setting where psychotherapeutic knowledge is still scarce or rarely applied.

An Algorithm for Jaw Pain among Divers

Background: Temporomandibular disease (TMD) is commonly seen, and divers also experience pain in the temporomandibular joint (TMJ) or masticatory muscles. This article aims to provide a tool for diving physicians or medical professionals involved in diving medicine since jaw pain among divers is a pertinent subject and can be challenging to evaluate without some background in dentistry or maxillofacial surgery. Method: A basic algorithm was developed to provide a tool to differentiate jaw pains experienced by divers. Three brief case studies were developed, and five diving physicians were tasked with diagnosing the cases using the algorithm. Additionally, simple exercises and massage techniques that can benefit patients with TMD, particularly immediately after diving, are outlined. Results: All five diving physicians successfully diagnosed the cases using the algorithm. However, three of them were unable to diagnose the first case (disc luxation) without consulting the algorithm. Nevertheless, all physicians acknowledged the utility of the algorithm. Conclusions: Jaw pain in divers can stem from diverse causes, but effective treatment options exist. Our study findings provide valuable insights to assist diving physicians in making accurate diagnoses and guiding appropriate patient management, which may include referrals to specialists such as dentists, maxillofacial surgeons, or orthodontists.

Etiologic Factors of Temporomandibular Disorders: A Systematic Review of Literature Containing Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) from 2018 to 2022

This study aims to conduct a systematic analysis of literature published between 1 January 2018 and 1 September 2022, exploring factors influencing the progression or development of temporomandibular disorders (TMD), diagnosed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) or Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Three electronic databases were reviewed to identify papers that examined TMD factors using DC/TMD or RDC/TMD. Inclusion criteria encompassed original research published in English between 1 January 2018 and 1 October 2022, online, and complete DC/TMD or RDC/TMD studies on human participants aged 18 or older. Two authors independently assessed the risk of bias using The Joanna Briggs Institute (JBI) Analytical cross-sectional studies' Critical Appraisal Tool. Of 1478 articles, 11 were included. The studies revealed strong associations between TMD and factors such as female, poor sleep quality, depression, oral parafunction, anxiety, somatization, and anatomical features. However, variables such as education, living conditions, socioeconomic status, marital status, chronic pain, and stress did not exhibit statistically significant correlations. Based on the obtained data, it can be concluded that the causes of TMD are largely related to psychological factors, which supports the biopsychosocial theory of the disorder.

The Biology of Stress Intolerance in Patients with Chronic Pain—State of the Art and Future Directions

Stress has been consistently linked to negative impacts on physical and mental health. More specifically, patients with chronic pain experience stress intolerance, which is an exacerbation or occurrence of symptoms in response to any type of stress. The pathophysiological mechanisms underlying this phenomenon remain unsolved. In this state-of-the-art paper, we summarised the role of the autonomic nervous system (ANS) and hypothalamus-pituitary-adrenal (HPA) axis, the two major stress response systems in stress intolerance. We provided insights into such mechanisms based on evidence from clinical studies in both patients with chronic pain, showing dysregulated stress systems, and healthy controls supported by preclinical studies, highlighting the link between these systems and symptoms of stress intolerance. Furthermore, we explored the possible regulating role for (epi)genetic mechanisms influencing the ANS and HPA axis. The link between stress and chronic pain has become an important area of research as it has the potential to inform the development of interventions to improve the quality of life for individuals living with chronic pain. As stress has become a prevalent concern in modern society, understanding the connection between stress, HPA axis, ANS, and chronic health conditions such as chronic pain is crucial to improve public health and well-being.

Effects of an intraoral device (IOD) on electromyographic activity on the masseter and temporal muscles in Class III patients

OBJECTIVE

Class III malocclusion is characterized by a loss of vertical dimension associated with muscle imbalance. The present study was designed to determine electromyographic amplitude changes in temporal (T) and masseter (M) at rest and during clenching in Class III patients treated with an intraoral device (IOD) over a 24-hour period for 30 days with transcutaneous electrical nerve stimulation (TENS).

METHODS

Twelve patients with Class III (mean age 27.7 ± 1.2 years) were treated with TENS and IOD. Ten untreated patients composed the control group. Data were analyzed using Wilcoxon test and ANOVA.

RESULTS

Patients treated with TENS and IOD showed a marked decrease in hyperactivity of M and T at rest (p = 0.001) and an increase during clenching (p = 0.001). The control group maintained similar activity in both positions.

CONCLUSION

This study confirms that using TENS and IOD in patients improves muscle activity of T and M.

The Relationship between Stress and Masticatory Muscle Activity in Female Students

The aim of the study was to analyze the relationship between stress measured by the perceived stress scale (PSS-10) questionnaire and masticatory muscle activity. Experimental design assumed the study of healthy young women without temporomandibular disorders, dividing them into three groups depending on the result of the stress level and then comparing these groups in terms of bioelectrical activity of the masticatory muscles. After the exclusion criteria were applied, 63 female students (mean age: 22.3 ± 2.4 years) from Medical University of Lublin were included in the study. The subjects were then divided into 3 groups: with low (n = 18), medium (n = 18) and high stress level (n = 27), according to PSS-10 results. Resting and functional activity of temporalis anterior (TA) and masseter (MM) muscles were measured by electromyograph BioEMG III. There were statistically significant effects of group on the absolute value of asymmetry index (AsI) of TA and MM during maximum voluntary clenching on dental cotton rollers (both p = 0.02). Post hoc analysis shows that there were statistically significant differences between medium and high stress groups in AsI TA (p = 0.01) and between low and high stress groups in AsI MM (p = 0.02). Perceived stress measured by PSS-10 questionnaire seems to be associated with changes in muscular asymmetry in functional clenching activity.

New aspects of the esophageal histology of the domestic goat (Capra hircus) and European roe deer (Capreolus capreolus)

The present study examines the esophageal wall of animals from two distinct families of the Ruminantia: domestic goats and European roe deer. Five fragments were collected from the entire length of the esophageal wall in five goats and four roe deer and subjected to microscopic and morphometric analyses. All layers of the esophageal wall except the tela submucosa were found to be thicker in the goats. In both species, the esophagus was lined by parakeratinized stratified squamous epithelium, and the tela submucosa was deprived of glands along its entire length. However, the structure of the lamina muscularis mucosae was better developed in goats: it was found to be discontinuous in the proximal part, and then became fused in the cervical part, that is around the most proximal quarter of its length. In contrast, in roe deer, the lamina muscularis mucosae began as sparse, thin muscle bundles at the pharyngeal-esophageal junction, which thickened and clustered further down the esophagus, but did not fuse. Our findings regarding the microscopic structure of the ruminant esophagus are not fully consistent with the widely-accepted view and suggest that the histological structure of the esophagus demonstrates interspecies variation within this large suborder. More precisely, species-specific differences can be seen regarding the presence of esophageal glands and parakeratinized epithelium, and in the organization of the lamina muscularis mucosae.

Metalloelastase-12 is involved in the temporomandibular joint inflammatory response as well as cartilage degradation by aggrecanases in STR/Ort mice

Temporomandibular joint dysfunction (TMJD) is characterised by clinical symptoms involving both the masticatory muscles and the temporomandibular joint (TMJ). Disc internal derangement and osteoarthritis (OA) are the most common forms of TMJD. Currently, the molecular process associated with degenerative changes in the TMJ is unclear. Our previous study showed that elastin-digested peptides act on human TMJ synovial cells and lead to upregulation of interleukin-6 (IL-6) and metalloelastase-12 (MMP-12; an elastin-degrading enzyme) in vitro. However, there is limited information regarding the involvement of elastin-degradation by MMP-12 in the processes of inflammatory responses and cartilage degradation in vivo. STR/Ort mice were used as a model of TMJ OA in the present study. Significant articular cartilage degeneration was observed starting at 20 weeks of age in the STR/Ort mice and this progressed gradually until 40 weeks, compared with the age-matched CBA mice. Immunostaining analysis showed that MMP-12 and IL-6 were expressed in the chondrocytes in the superficial zones of the cartilage. Immunostaining also showed that aggrecanases [a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5] were expressed in the chondrocytes in the superficial zones of the cartilage. These findings suggest that an inflammatory and degradative process was initiated in the TMJ. Harmful mechanical stimuli, particularly pressure, may cause damage to the elastin fibres in the most elastin-rich superficial layer of the articular cartilage. Elastin-digested peptides are then generated as endogenous warning signals and they initiate a pro-inflammatory cascade. This leads to upregulation of pro-inflammatory mediators, such as IL-6 and MMP-12, which further trigger tissue damage resulting in elevated levels of elastin-digested peptides. IL-6 increases expression of the aggrecanases ADAMTS-4 and ADAMTS-5, following cartilage degradation. This leads to the establishment of a positive feedback loop and may result in chronic inflammation and cartilage degradation of the TMJ in vivo.

Coronavirus Lockdown as a Major Life Stressor: Does It Affect TMD Symptoms?

Temporomandibular disorders are multi-factorial conditions that are caused by both physical and psychological factors. It has been well established that stress triggers or worsens TMDs. This paper looks to present early research, still unfolding, on the relationship between COVID-19 as a major life stressor and TMDs. The main aims of this study were to: investigate the presence of symptoms related to TMDs and the time of onset and the worsening of painful symptoms in relation to the changes in social life imposed by the coronavirus pandemic; and to evaluate the perception of COVID-19 as a major stressful event in subjects who report worsening of painful TMD symptoms. One hundred and eighty-two subjects answered questionnaires-Axis II of the RDC/TMD, the PSS, and specific items about coronavirus as a stressful event-during the lockdown period for COVID-19 in Italy to evaluate the presence of reported symptoms of TMD and the level of depression, somatization, and stress perceived. The results showed that 40.7% of subjects complained about TMD symptoms in the past month. Regarding the time of onset, 60.8% of them reported that facial pain started in the last three months, while 51.4% of these subjects reported that their symptoms worsened in the last month and were related to the aggravation of pain due to the coronavirus lockdown as a major life event and to the stress experienced. The results of this study seem to support the hypothesis that stress during the pandemic lockdown influenced the onset of temporomandibular joint disorders and facial pain, albeit with individual responses.

Electromyographic analysis of stomatognathic muscles in elderly after hippotherapy

The aging process affects the entire human body, including the stomatognathic system, and can trigger not only occlusal but also postural imbalances involving other muscular chains. Hippotherapy has been used to promote cervical, postural, and balance control in individuals with diverse impairments. The present study used electromyography to evaluate the masseter and temporal muscles in an elderly population pre- and post-hippotherapy. Participants included 17 individuals, mean age 66,5±7 years. Electromyographic recording of the bilateral masseter and temporal muscles was performed during the postural resting condition and activities that involved the active participation of these muscles in different conditions. The practitioner performed no other type of activity or exercise during the intervention because the objective is to evaluate the effect of the three-dimensional movement provided by the horse. Raw electromyographic data were tabulated using commercially available software (IBM® SPSS® Statistics 234.0) and subjected to statistical analysis, in which p ≤ 0.05 was considered to be statistically significant. Post-hippotherapy, there was lower electromyographic activity for the masseter and temporalis muscles in all the static mandibular tasks, with significant effect for time for the right temporal muscle (p = 0.038), the left temporal muscle (p = 0.028) and in the all dynamic mandibular tasks for the left temporal muscle (p = 0.025) and the left masseter muscle (p = 0.027). Hippotherapy promotes a reduction in the myoelectric activity of the masticatory muscles of elderly individuals.

Cervical spine range of motion, posture and electromyographic activity of masticatory muscles in temporomandibular disorders

Abstract Introduction: Temporomandibular joint disorders (TMD or TMJD) involve clinical problems and symptoms affecting the temporomandibular joint (TMJ) and associated structures. The temporomandibular joints are anatomically connected to the cervical region, where cervical spine movements occur simultaneously to masticatory muscle activation and jaw movements. Objective: Our study sought to assess the relationship between the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), surface electromyography (sEMG) of the masticatory muscles, posture and cervical flexibility in women with TMD. Method: Fifty women with an average age of 27.0 ± 6.37 years, diagnosed with TMD according to RDC/TMD, were assessed for craniocervical posture, cervical flexibility and sEMG of the masticatory muscles. Results: There were no differences in jaw function limitations, depression, pain level and its interference in work ability and daily activities, posture and sEMG between TMD diagnoses or between muscle classification (p > 0.05). Depression scores were higher among participants with biarticular dysfunction (p = 0.023). The group with bruxism exhibited a higher pain level at assessment (p = 0.001) and a greater reduction in work ability (p = 0.039). Subjects with muscular and mixed TMD showed less cervical rotation to the right when compared with those with articular TMD. Conclusion: There was no difference in posture or sEMG values for TMD diagnoses, joint and muscle dysfunctions and the presence of bruxism. Muscle dysfunction is associated with reduced cervical rotation to the right. Jaw function limitations did not interfere in posture or sEMG and depression was associated with pain.

Alterations in Surface Electromyography Are Associated with Subjective Masticatory Muscle Pain

Background

Tenderness of masseters and temporalis can be considered a relevant tool for diagnosis of myo-type craniofacial pain disorders, but a limit of pain score systems is that they are based on subjective pain perception. Surface electromyography (sEMG) is a noninvasive and reliable tool for recording muscle activity. Therefore, we investigated whether a correlation exists between tenderness on masseters and temporalis, assessed by subjective pain scale, and muscles activity, evaluated by sEMG, in patients with painful temporomandibular disorder (TMD) and concurrent tension-type headache (TTH).

Methods

A cross-sectional study on fifty adult volunteer patients with TMD and TTH, who underwent tenderness protocol according to Diagnostic Criteria for TMD (DC/TMD) guidelines, was conducted followed by sEMG recording of temporalis and masseters. Pearson's correlation was performed to investigate the correlation between muscular activity and subjective pain scores.

Results

An overall moderate correlation between muscle tenderness and sEMG values (y = 1 + 1.2 · x; r² = 0.62; p < 0.0001), particularly in the temporalis, was observed. Segregation of data occurred according to tenderness and sEMG values. At the highest pain score, the mean sEMG absolute value was higher at the temporalis than the masseters.

Conclusions

Our study provides evidence that subjective pain perception can be objectively quantified at a magnitude proportional to pain severity. At greater tenderness scores, higher sEMG activity at the level of temporalis could help discriminate clinically prevalent TTH versus prevalent TMD. sEMG confirms to be an accurate tool to reliably objectify the subjective perception of pain. When combined with clinical evaluation and patients' symptoms, sEMG increases diagnostic sensitivity in the field of myo-type craniofacial pain disorders. This trial is registered with NCT02789085.

Influence of tongue exercise and orofacial myofunctional status on the electromyographic activity and pain of chronic painful TMD

Objective: To analyze the influence of tongue exercise and myofunctional status on the electromyographic activity (EMG) and pain perception in individuals with chronic painful TMDs.Methods: Twenty-four subjects diagnosed according to the DC/TMD (18-52 years old) were assessed: EMG on the masseter and anterior temporalis; myofunctional orofacial conditions underwent clinical assessment (OMES); and questionnaire for self-perception of TMD signs and symptoms (ProTMDMulti). The 50th percentile was calculated to establish a cutoff value based on OMES scores related to the functional variables of the tongue.Results: The compared groups showed no differences (p > 0.05) in self-perception of their TMD signs and symptoms or in the EMG activity during tongue exercises.Discussion: The myofunctional status of the tongue showed no impact on the painful TMD or on the activity of the masticatory muscles (captured during tongue exercise). The indication of tongue exercises in TMD cases is a safe and adequate possibility.

Dysfunctional stress responses in chronic pain

Many dysfunctional and chronic pain conditions overlap. This review describes the different modes of chronic deregulation of the adaptive response to stress which may be a common factor for these conditions. Several types of dysfunction can be identified within the hypothalamo-pituitary-adrenal axis: basal hypercortisolism, hyper-reactivity, basal hypocortisolism and hypo-reactivity. Neuroactive steroid synthesis is another component of the adaptive response to stress. Dehydroepiandrosterone (DHEA) and its sulfated form DHEA-S, and progesterone and its derivatives are synthetized in cutaneous, nervous, and adipose cells. They are neuroactive factors that act locally. They may have a role in the localization of the symptoms and their levels can vary both in the central nervous system and in the periphery. Persistent changes in neuroactive steroid levels or precursors can induce localized neurodegeneration. The autonomic nervous system is another component of the stress response. Its dysfunction in chronic stress responses can be expressed by decreased basal parasympathethic activity, increased basal sympathetic activity or sympathetic hyporeactivity to a stressful stimulus. The immune and genetic systems also participate. The helper-T cells Th1 secrete pro-inflammatory cytokines such as IL-1-β, IL-2, IL-6, IL-8, IL-12, IFN-γ, and TNF-α, whereas Th2 secrete anti-inflammatory cytokines: IL-4, IL-10, IGF-10, IL-13. Chronic deregulation of the Th1/Th2 balance can occur in favor of anti- or pro-inflammatory direction, locally or systemically. Individual vulnerability to stress can be due to environmental factors but can also be genetically influenced. Genetic polymorphisms and epigenetics are the main keys to understanding the influence of genetics on the response of individuals to constraints.