Association between estrogen levels and temporomandibular disorders: a systematic literature review

Global Prevalence of Sleep Bruxism and Awake Bruxism in Pediatric and Adult Populations: A Systematic Review and Meta-Analysis

Background/Objectives: The purpose of this systematic review was to assess the global prevalence of sleep bruxism and awake bruxism in pediatric and adult populations. Methods: This systematic review was conducted by analyzing studies published from 2003 to 2023. The following keyword combination was utilized: prevalence, epidemiology, population, and bruxism. The PubMed database was analyzed, supplemented by manual searches using the Google search. Additionally, the snowballing procedure method was applied. A double assessment of the quality of publications was carried out to preserve the highest possible quality of evidence (e.g., Joanna Briggs Institute critical appraisal checklist). Analyses were conducted using the R statistical language. Results: The global bruxism (sleep and awake) prevalence is 22.22%. The global sleep bruxism prevalence is 21% and awake prevalence is 23%. The occurrence of sleep bruxism, based on polysomnography, was estimated at 43%. The highest prevalence of sleep bruxism was observed in North America at 31%, followed by South America at 23%, Europe at 21%, and Asia at 19%. The prevalence of awake bruxism was highest in South America at 30%, followed by Asia at 25% and Europe at 18%. Conclusions: One in four individuals may experience awake bruxism. Bruxism is a significant factor among women. It was observed that age is a significant factor for the occurrence of sleep bruxism in women. Among the limitations of the study is the lack of analysis of the prevalence of bruxism in Africa and Australia due to not collecting an adequate sample for analysis. The study was registered in the Open Science Framework (10.17605/OSF.IO/ZE786).

Mechanisms Underlying Sex Differences in Temporomandibular Disorders and Their Comorbidity with Migraine

Sexual dimorphism in temporomandibular disorders (TMDs) and their comorbidity with migraine are important phenomena observed in clinics. TMDs are the most prevalent orofacial pain conditions with jaw joint and masseter muscle dysfunction. Migraine is the predominant headache commonly associated with TMDs. Women much more often suffer from this orofacial pain than men. However, currently, there is no gender-specific therapy for such pain conditions. Understanding the pathophysiological mechanisms behind sex differences in TMDs as well as their comorbidity with migraines is essential for developing novel approaches for gender-specific treatment of TMDs and related orofacial pain comorbidity. In this review, we summarize recent research progress regarding sex differences in TMDs, focusing on the underlying mechanisms including craniofacial anatomy, hormonal regulation, and roles of opioids, transient receptor potential channels, and endocannabinoid systems. We also discuss the mechanisms of comorbid TMDs and migraine. The information covered in this review will provide mechanistic insights into sex differences in TMDs and their comorbidity with migraine, which could aid in developing effective treatment strategies for the overlapping orofacial pain condition.

Hormone replacement therapy did not alleviate temporomandibular joint inflammatory pain in ovariectomized rats

This study had the aim of examining the relationships between variations in estrogen levels resulting from ovariectomy, and estrogen hormone replacement therapy (HRT) in rats subjected to an orofacial inflammatory pain model. Eighty adult female Wistar rats were initially divided into 2 groups: Sham or ovariectomy (OVX-D1). Seven days later (D7), the rats were subjected to an unilateral infiltration of Freund's Complete Adjuvant (CFA) or saline solution into the right temporomandibular joint (TMJ). Then, rats received 17β-estradiol (28 µg/kg/day) or placebo for 21 days (D10-D31). Nociception was evaluated by the von Frey (VF) and the Hot Plate (HP) tests, and depressive-like behavior by the Forced Swimming (FS) test. On D32 all rats were euthanized and serum, hippocampus and brainstem were collected. The CFA groups presented a mechanical hyperalgesia until day 21 (p ≤ 0.05). No differences were observed among groups in the HP (p = 0.735), and in the immobility and swimming time of the FS (p = 0.800; p = 0.998, respectively). In the brainstem, there was a significant difference in the TNF-ɑ levels (p = 0.043), and a marginal significant difference in BDNF levels (p = 0.054), without differences among groups in the hippocampal BDNF and TNF-ɑ levels (p = 0.232; p = 0.081, respectively). In conclusion, the hormone replacement therapy did not alleviate orofacial pain in ovariectomized rats. However, there is a decrease in brainstem TNF-ɑ levels in the animals submitted to both models, which was partially reverted by HRT.

Effectiveness of a home exercise program when added to a conventional physiotherapy program in patients with temporomandibular disorders: A comparative study

OBJECTIVE

This study aimed to investigate the effect of a home exercise program on pain and quality of life (QoL) in TMD.

METHODS

Twenty patients were included in the study. The Group A received both a home exercise program and a physiotherapy program, while only a physiotherapy program was given to the Group B. Pain was measured using the Visual Analogue Scale (VAS) and QoL using the Short-Form 36 (SF-36).

RESULTS

Pain decreased in both groups (p < 0.05). Among the SF-36 domains, bodily pain, vitality and social functioning scores improved in the Group A, while only the bodily pain parameter improved in the Group B (p < 0.05). On between-group comparison, the positive effect on pain and quality of life was greater in the Group A (p < 0.05).

CONCLUSION

The addition of a home exercise program to the conventional physiotherapy program provided greater improvement in pain and QoL in patients with TMD.

Do steroid abusers have more temporomandibular joint symptoms? A study with 97 bodybuilders

OBJECTIVES

Anabolic androgenic steroids (AAS) are derivatives of testosterone, used to treat gonadal disturbances, performance enhancement, and aesthetic purposes. AAS abuse can lead to side effects, including androgenic, cardiovascular, and liver disturbances, effects on libido, gynecomastia, and behavioral effects. There is a hypothesis that some joint tissues may be targets for sex hormones, and the use of AAS without medical follow-up may exacerbate temporomandibular joint problems in patients seeking performance and aesthetics.

METHODS

In this study, a cross-sectional survey was conducted on AAS abusers who voluntarily presented themselves for clinical evaluation. Patients were subdivided by sex and age group, and the length of AAS use and symptoms such as headache, tinnitus, and temporomandibular joint pain were evaluated.

RESULTS

It was observed that drug usage is related to symptoms.

CONCLUSION

The results suggest that AAS use without medical follow-up may exacerbate temporomandibular joint problems, especially in patients with low estrogen levels.

Occurrence of Cervical Spine Pain and Its Intensity in Young People with Temporomandibular Disorders

Background: The main aim of this cross-sectional study was to compare the occurrence and severity of cervical spine pain in young adults diagnosed with TMDs with a healthy control group (without TMDs). Methods: The study was conducted from June to July 2023. Inclusion criteria were age (18-30 years), cervical spine pain (for at least 1 month), and consent to participate in the study. The study was conducted based on RDC/TMD protocol, an original questionnaire, and a physiotherapeutic examination focused on detecting TMDs. The cervical pain level was assessed using the Visual Analogue Scale (VAS). Thus, a total of 95 subjects were registered for the trials, 51 people (53.7%) constituted the control group (without TMDs), while 44 (46.3%) people constituted the study group (with TMDs). Results: The mean age of people participating in the study was 22.2 ± 2.2 years in the study group and 22.5 ± 3.1 years in the control group. The largest group was people aged 21-25 (n = 51 people, 53.7%). Patients from the study group more often experienced pain in the stomatognathic system during palpation (both in the muscle, joint, and musculoskeletal groups) and had reduced mobility of the temporomandibular joints in every movement (p < 0.001). People from the study group were also characterized by less mobility of the cervical spine (p < 0.05), apart from extension movement (p > 0.05). The analysis showed that of the 95 people participating in the study, 85.4% reported problems in the cervical spine area (n = 81), of which almost all people in the study group struggled with this problem (n = 43, 97.7%). It was found that cervical spine pain was significantly more common in people with TMDs (p < 0.05, chi2 = 10.118, df = 1, rc = 0.31). The level of pain was significantly higher in people from the study group (p < 0.001, chi2 = 45.765, df = 4, rc = 0.57). Conclusions: Our research has shown that the occurrence of cervical spine pain is more common in the group of young people with temporomandibular disorders (TMDs). In young people, this problem is rarely recognized and properly treated.

The relationship between pregnancy and temporomandibular disorder (TMD) through diagnostic criteria for temporomandibular disorders (DC/TMD) axis II evaluation: a case-control cross-sectional study

INTRODUCTION

This study focuses on temporomandibular disorders (TMDs), which affect the temporomandibular joint and related muscles and have multiple causes. Recent studies have examined the connection between menstrual cycles, estrogen levels, and TMDs, but results are inconsistent, highlighting the need for more research. The aim is to explore the prevalence of TMDs in pregnant women and consider how hormonal changes during pregnancy might influence these disorders.

METHODS

In this cross-sectional case-control study, we compared 32 pregnant women with 35 non-pregnant women. We evaluated several TMD-related factors such as pain levels, chronic pain classification, scores on the Jaw Functional Limitation Scale-20 and Oral Behaviors Checklist, and psychological health. We used various statistical methods including descriptive statistics, chi-square tests, linear regression, and adjustments for multiple comparisons to analyze the data.

RESULTS

Pregnant women showed different pain perceptions, generally reporting less pain and lower severity. Nonetheless, these differences were not uniform across all TMD-related measures. Linear regression did not find a consistent link between pregnancy and TMD scores, except for chronic pain grade, which was not significant after adjusting for multiple comparisons. There was a significant relationship between depression and TMD severity, emphasizing the need to consider mental health in TMD evaluations.

DISCUSSION

The findings suggest that pregnancy is neither a risk nor a protective factor for TMD. Differences in pain perception, functional status, and psychological health were observed in pregnant women but were not consistent for all TMD-related aspects. The role of estrogen in TMJ health and TMD risk is complex and requires further study. The research highlights the necessity of including mental health, especially depression, in TMD assessments. More comprehensive research with larger sample sizes is essential to better understand the connections between pregnancy, TMD, and hormones, aiming to improve TMD management in pregnant women and others.

Correlating estrogen replacement therapy and temporomandibular disorders: a comprehensive review following PRISMA principles and cochrane handbook for systematic reviews of interventions

BACKGROUND

Estrogen replacement therapy (ERT) is a common hormonal treatment for postmenopausal women, aimed at alleviating menopausal symptoms and reducing the health risks associated with estrogen deficiency. However, the impact of ERT on temporomandibular disorders (TMDs) remains unclear. This systematic review aims to evaluate the relationship between ERT and TMDs, including TMD occurence, pain, and associated symptoms.

METHODS

A comprehensive search of seven electronic databases was conducted using predefined search terms and Boolean operators. Inclusion criteria encompassed studies examining the association between ERT and TMDs. Two independent reviewers screened the identified articles, extracted data, and assessed the risk of bias using the RoB -2 tool.

RESULTS

Search strategy identified a total of 3 articles which met the inclusion criteria. The included studies investigated the impact of ERT on TMD occurrence and its related symptoms. The analysis revealed no significant association between ERT and TMD occurrence. A significant dose relationship was noted in one of the studies while another mentioned the possible relationship of TMD with educational status. Risk of bias among the studies was low, and the overall quality of evidence was deemed to be high.

CONCLUSION

This systematic review suggests that there is no conclusive evidence supporting an increased risk of TMDs among women receiving ERT. The findings indicate that ERT is unlikely to have a noticeable impact on TMDs. However, due to the limited number of studies available, further research is warranted to strengthen these conclusions and explore potential factors that may influence the relationship between ERT and TMDs.

Prevalence of Temporomandibular Disorder-Related Pain among Adults Seeking Dental Care: A Cross-Sectional Study

Objectives

Temporomandibular disorders (TMD) are a constellation of painful conditions that affect the craniofacial complex. The etiology and risk factors of these conditions have been extensively studied; however, the data available describing the epidemiology of TMD in the Middle East are scarce. We aimed to estimate the prevalence and risk factors of TMD-related pain in a sample population of dental school clinic patients.

Methods

This observational cross-sectional study used a translated and culturally adapted temporomandibular disorders pain screener, a part of the Diagnostic Criteria/Temporomandibular Disorders (DC/TMD) criteria instrument, and questions related to demographic characteristics and risk factors for TMD. Data were analyzed through chi-square and Mann-Whitney U tests using SPSS.

Results

The sample population included 199 participants (66% female and 34% male). The prevalence of TMD-related pain was 26.8% (n = 42); men and women did not differ statistically in their TMD-related pain. TMD-related pain cases differed significantly on the Center for Epidemiologic Studies Depression Scale (CES-D) and body pain scores compared with noncases.

Conclusion

The prevalence of TMD-related pain in the clinical sample population was high. Hence, the onus is on dental health services to screen and educate patients on TMD conditions regularly.

Psychologic Impact of Chronic Orofacial Pain: A Critical Review

AIMS

To explore the prevalence of clinically significant anxiety and depression in adult patients with chronic orofacial pain (COFP) conditions.

METHODS

A systematic online search of the Medline (PubMed) and Ovid databases was performed for articles published from 2006 to 2019. Observational studies- including cross-sectional, case-control, and case series-and longitudinal prospective studies were included. A total of 118 articles were selected for inclusion, and the prevalence rates of clinically significant anxiety and depression were summarized.

RESULTS

Most studies focused on temporomandibular disorder (TMD) pain and less often on neuropathic COFP conditions. Prevalence rates varied widely across studies according to OFP condition and assessment measure; most questionnaire-based assessments yielded rates of clinically significant depression and anxiety in, respectively, 40% to 60% and 40% to 65% of individuals with TMD and in 20% to 50% and 25% to 55% of patients with neuropathic, mixed, or idiopathic/atypical COFP conditions. Rates of anxiety and depression were lower in studies using diagnostic instruments and in TMD studies with nonpatient samples. Most controlled studies showed a higher prevalence of anxiety and depression in individuals with COFP than in those without. Higher COFP pain levels and the presence of comorbid conditions such as migraines or widespread pain increased the likelihood of anxiety and/or depressive symptoms in individuals.

CONCLUSION

Clinically significant anxiety and depression were commonly observed in patients with COFP, were present at higher rates than in pain-free participants in controlled studies, and were closely linked to pain severity. More research is needed to evaluate the psychologic impact of multiple COFP conditions in an individual and the prevalence of precondition psychologic morbidity.

Craniofacial Morphology of Orthodontic Patients with and without Temporomandibular Disorders: A Cross-Sectional Study

Purpose

We aimed to explore the relationship between temporomandibular disorders (TMDs) and craniofacial morphology in orthodontic patients.

Methods

Altogether, 262 orthodontic patients were included and divided into two groups according to their Fonseca Anamnestic Index (FAI) scores: a no-TMD group (control group, FAI < 20) and a TMD group (FAI ≥ 20). Cephalometric parameters including cranial, maxillary, mandibular, and dental parameters were traced on cephalograms. Craniofacial morphology was compared between TMD and control groups, followed by subgroup analyses based on TMD severity, gender, age, and temporomandibular joint (TMJ) symptoms.

Results

The prevalence of TMDs was 52.7% among included patients (138/262). The mean age of TMD patients was higher than that of the control group. No significant difference in gender distribution between the groups was observed. The most commonly reported FAI items were misaligned teeth, neck pain, and emotional tension. The Frankfort-mandibular plane angle (FMA) was larger in the TMD patients than in the control group, whereas no significant differences in other parameters were observed. Subgroup analysis based on TMD severity revealed that FMA and anterior facial height of moderate/severe TMD patients were significantly larger than those of mild or no-TMD patients. Among male patients, the anterior cranial base length was smaller, and the anterior facial height was larger in the TMD group. Among female patients, no significant differences in craniofacial morphology between the groups were observed. In juvenile patients, overjet and overbite were smaller in the TMD group. In adult patients, SNA, ANB, FMA, and gonial angle were larger in the TMD group. Within the TMD group, patients with TMJ pain or noises exhibited characteristic craniofacial features compared to patients without these symptoms.

Conclusions

Orthodontic patients with TMDs have specific craniofacial morphology, suggesting a relationship between TMDs and particular craniofacial features in orthodontic patients.

Preclinical models of deep craniofacial nociception and temporomandibular disorder pain

Chronic pain in temporomandibular disorder (TMD) is a common health problem. Cumulating evidence indicates that the etiology of TMD pain is complex with multifactorial experience that could hamper the developments of treatments. Preclinical research is a resource to understand the mechanism for TMD pain, whereas limitations are present as a disease-specific model. It is difficult to incorporate multiple risk factors associated with the etiology that could increase pain responses into a single animal. This article introduces several rodent models which are often employed in the preclinical studies and discusses their validities for TMD pain after the elucidations of the neural mechanisms based on the clinical reports. First, rodent models were classified into two groups with or without inflammation in the deep craniofacial tissues. Next, the characteristics of each model and the procedures to identify deep craniofacial pain were discussed. Emphasis was directed on the findings of the effects of chronic psychological stress, a major risk factor for chronic pain, on the deep craniofacial nociception. Preclinical models have provided clinically relevant information, which could contribute to better understand the basis for TMD pain, while efforts are still required to bridge the gap between animal and human studies.

TMD in Females with Menstrual Disorders

BACKGROUND

Temporomandibular disorders (TMD) are a common reason for patients to present at dental offices. The majority of people with TMD are women between the age of 20 and 40 years. The purpose of this study was to assess the types and prevalence of temporomandibular disorders in female patients of reproductive age with menstrual disorders.

MATERIALS AND METHODS

The study involved 65 females of reproductive age (18-40 years, an average of 28.00 ± 6.27 years). The women who qualified for the study were patients of the University Center for Maternal and Newborn's Health hospitalized because of infertility or menstrual cycle disorders. Women with confirmed estrogen metabolism disorders participated in a clinical study with the use of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD).

RESULTS

In the studied female patients with menstrual disorders, temporomandibular disorders (92.3%) were frequent occurrences. The most common type was intra-articular joint disorders (68%). Other reported complaints included masticatory muscle pain (44.62%), and degenerative joint diseases (12.3%).

CONCLUSIONS

1. In women with menstrual disorders, TMD may exist. 2. In women with TMD symptoms, their medical history should be extended to include the diagnosis of female hormone disorders.

Knee orthopedics as a template for the temporomandibular joint

Although the knee joint and temporomandibular joint (TMJ) experience similar incidence of cartilage ailments, the knee orthopedics field has greater funding and more effective end-stage treatment options. Translational research has resulted in the development of tissue-engineered products for knee cartilage repair, but the same is not true for TMJ cartilages. Here, we examine the anatomy and pathology of the joints, compare current treatments and products for cartilage afflictions, and explore ways to accelerate the TMJ field. We examine disparities, such as a 6-fold higher article count and 2,000-fold higher total joint replacement frequency in the knee compared to the TMJ, despite similarities in osteoarthritis incidence. Using knee orthopedics as a template, basic and translational research will drive the development and implementation of clinical products for the TMJ. With more funding opportunities, training programs, and federal guidance, millions of people afflicted with TMJ disorders could benefit from novel, life-changing therapeutics.

Therapeutic Agents for the Treatment of Temporomandibular Joint Disorders: Progress and Perspective

Temporomandibular joint disorders (TMD) are a common health condition caused by the structural or functional disorders of masticatory muscles and the temporomandibular joint (TMJ). Abnormal mandibular movement in TMD patients may cause pain, chronic inflammation, and other discomfort, which could be relieved by a variety of drugs through various delivery systems. In this study, we summarized commonly used therapeutic agents in the management of TMD as well as novel bioactive molecules in preclinical stage and clinical trials. The emerging therapy strategies such as novel intra-TMJ delivery systems and implants based on tissue engineering are also discussed. This comprehensive review will strengthen our understanding of pharmacological approaches for TMD therapy.

Nociceptive behavioural assessments in mouse models of temporomandibular joint disorders

Orofacial pain or tenderness is a primary symptom associated with temporomandibular joint (TMJ) disorders (TMDs). To understand the pathological mechanisms underlying TMDs, several mouse models have been developed, including mechanical stimulus-induced TMD and genetic mouse models. However, a lack of feasible approaches for assessing TMD-related nociceptive behaviours in the orofacial region of mice has hindered the in-depth study of TMD-associated mechanisms. This study aimed to explore modifications of three existing methods to analyse nociceptive behaviours using two TMD mouse models: (1) mechanical allodynia was tested using von Frey filaments in the mouse TMJ region by placing mice in specially designed chambers; (2) bite force was measured using the Economical Load and Force (ELF) system; and (3) spontaneous feeding behaviour tests, including eating duration and frequency, were analysed using the Laboratory Animal Behaviour Observation Registration and Analysis System (LABORAS). We successfully assessed changes in nociceptive behaviours in two TMD mouse models, a unilateral anterior crossbite (UAC)-induced TMD mouse model and a β-catenin conditional activation mouse model. We found that the UAC model and β-catenin conditional activation mouse model were significantly associated with signs of increased mechanical allodynia, lower bite force, and decreased spontaneous feeding behaviour, indicating manifestations of TMD. These behavioural changes were consistent with the cartilage degradation phenotype observed in these mouse models. Our studies have shown reliable methods to analyse nociceptive behaviours in mice and may indicate that these methods are valid to assess signs of TMD in mice.

Emerging Potential of Exosomes in Regenerative Medicine for Temporomandibular Joint Osteoarthritis

Exosomes are nanosized vesicles (30–140 nm) of endocytic origin that play important roles in regenerative medicine. They are derived from cell membranes during endocytic internalization and stabilize in biological fluids such as blood and synovia. Temporomandibular joint osteoarthritis (TMJ OA) is a degenerative disease, which, in addition to chronic pain, is characterized by progressive cartilage breakdown, condylar bone remodeling, and synovitis. However, traditional clinical treatments have limited symptom- and structure-modifying effects to restore damaged cartilage and other TMJ tissues. This is due to the limited self-healing capacity of condylar cartilage. Recently, stem-cell-derived exosomes have been studied as an alternative therapeutic approach to tissue repair and regeneration. It is known that trophic regulation of mesenchymal stem cells (MSCs) has anti-inflammatory and immunomodulatory effects under pathological conditions, and research on MSC-derived exosomes is rapidly accumulating. MSC-derived exosomes mimic the major therapeutic effects of MSCs. They affect the activity of immune effector cells and possess multilineage differentiation potential, including chondrogenic and osteogenic differentiation. Furthermore, exosomes are capable of regenerating cartilage or osseous compartments and restoring injured tissues and can treat dysfunction and pain caused by TMJ OA. In this review, we looked at the uniqueness of TMJ, the pathogenesis of TMJ OA, and the potential role of MSC-derived exosomes for TMJ cartilage and bone regeneration.

Recent Tissue Engineering Advances for the Treatment of Temporomandibular Joint Disorders

Temporomandibular disorders (TMDs) are among the most common maxillofacial complaints and a major cause of orofacial pain. Although current treatments provide short- and long-term relief, alternative tissue engineering solutions are in great demand. Particularly, the development of strategies, providing long-term resolution of TMD to help patients regain normal function, is a high priority. An absolute prerequisite of tissue engineering is to understand normal structure and function. The current knowledge of anatomical, mechanical, and biochemical characteristics of the temporomandibular joint (TMJ) and associated tissues will be discussed, followed by a brief description of current TMD treatments. The main focus is on recent tissue engineering developments for regenerating TMJ tissue components, with or without a scaffold. The expectation for effectively managing TMD is that tissue engineering will produce biomimetic TMJ tissues that recapitulate the normal structure and function of the TMJ.

Association of temporomandibular disorder with occupational visual display terminal use

Increased visual display terminal (VDT) use has raised the prevalence of VDT-related adverse conditions, such as dry eye disease, and musculoskeletal and psychopathological symptoms, in office workers, including temporomandibular disorder (TMD). Many factors contributing to TMD have been identified, such as parafunctional habit (bruxism and teeth clenching), trauma, mental disorders, lifestyle, poor health, and nutrition, as well as hormonal factors (i.e., estrogen). It is likely that various contributing factors overlap in TMD development in individuals who routinely use a VDT for work. However, the relationship between TMD and VDT use has not been fully elucidated. In this mini-review, findings of recent studies of TMD in relation to occupational VDT use in Japan are discussed, as well as characteristic features and prevention strategies.