Recent Advancements in Temporomandibular Disorders (TMDs)

The impact of various subtypes of temporomandibular disorders on body balance - preliminary study

BACKGROUND

Balance disorders are considered a serious diagnostic challenge, with many potential causes. The influence of temporomandibular disorders (TMD) on postural balance has numerous anatomical, biomechanical, physiological and functional argumentation, however, cohort studies on this subject do not give unambiguous results. It is suggested that only some forms of TMD may affect the body balance.

RESEARCH QUESTION

Will body balance parameters differ in patients with particular subtypes of temporomandibular disorders and without temporomandibular disorders?

METHODS

cohort study. A total of 25 participants with TMD (9 with myofascial subtype; 9 with disc disorders subtype; 7 with mixed diagnosis) and 11 participants without TMD (control group) diagnosed by Research Diagnostic Criteria for TMD were assessed for body balance changes using force platform FreeMED MAXI ground reaction force platform (Sensor Medica; Guidonia Montecelio, Roma, Italia) under different mandibular conditions (rest position, clenching, clenching on cotton rolls). For the statistical analysis, the postural sway area of the Center of Pressure (COP) and its velocity were used.

RESULTS

The greatest differences in the sway area of the COP and its velocity were noticed when comparing the control group and the group with myofascial disorders. Statistically significant differences regarding the sways of COP in different mandible conditions were also shown by intragroup analyses in the group with myofascial and mixed forms. Both the results of the intra- and intra-group analyses shows that the involvement of the muscular factor may determine the occurrence of deviations in the body balance.

SIGNIFICANCE

The results of the project may extend the diagnosis of patients with balance disorders to the diagnosis of the masticatory system to accurately determine the source of the patient's problem.

The Coexistence of Tinnitus and Temporomandibular Disorder: A Narrative Review on the Importance of an Interdisciplinary Approach

This review focuses on the coexistence of tinnitus and temporomandibular disorders in terms of epidemiological data, etiology, differential diagnosis, treatment, and interaction between the two disorders. PubMed, Google Scholar, and ClinicalKey digital databases were used to search for publications covering the years 2009-2024. Finally, 77 publications were used. The review followed recommendations of the Scale for the Assessment of Narrative Review Articles. The prevalence of tinnitus in individuals with TMD amounted to 2-59% and was reported as the main concomitant symptom. Several studies reported that tinnitus was eight times more common in TMD sufferers. Among patients with tinnitus, TMJ disorders were observed at a frequency of 19%, while in the group presenting with a high severity of the condition, TMJ disorders were observed more frequently (36%). Based on this review, in order to facilitate the diagnosis and future treatment of tinnitus and TMD patients, a proposal for a multidisciplinary diagnostic algorithm is presented in the article. The cooperation of an otolaryngologist, audiologist, neurologist, psychiatrist, dentist, and physiotherapist may be considered in clinical settings.

Can intra-articular daidzein injection reduce oxidative damage and early osteoarthritis in a rabbit temporomandibular joint model?

BACKGROUND

Oxidative damage and inflammatory cytokines in osteoarthritis (OA) exacerbate the disease course. Daidzein (DZ) has antioxidant and anti-inflammatory effects. This study evaluated the early histopathological effects of intra-articular daidzein injection on experimentally induced osteoarthritis in rabbit TMJs.

METHODS

The predictor variable was intra-articular injection of DZ or a saline control. 50 µl of 3 mg/mL MIA solution was injected into the right TMJ of 16 New Zealand rabbits to induce experimental OA. One rabbit was sacrificed after 4 weeks to confirm the formation of the OA model and the OA model was obtained. The remaining 15 rabbits were randomly divided into 2 groups: an experimental group (9 rabbits) and a control group (6 rabbits). On days 1, 7, 14, and 21; 50 µl of saline solution was applied to the right TMJ of the control group and 50 µl daidzein solution (1.8 mg/ml) was applied to the right TMJ to the experimental group. After one week from the date of the last injection, the rabbits were sacrificed, and histopathological and biochemical evaluations were performed. The Shapiro-Wilk test was used to evaluate whether the variables in the study conformed to normal distribution. Mean ± SD (standard deviation) or median (interquartile range (IQR)) was used to show the descriptive statistics of the variables. T-test and Mann Whitney U test were used to compare the control and experimental groups for biochemical changes. The chi-square test was used to show the distribution of histopathological changes variables obtained within the scope of the study based on control and experimental groups. A P-value < 0.05 was considered significant for all evaluations.

RESULTS

There were 8 and 6 animate treated with DZ and saline, respectively. There was no statistically significant difference between groups in articular cartilage (p = 0.3), osteochondral junction (p = 0.3), subchondral bone structure (p = 1.0) or chondrocyte appearance (p = 0.4). The experimental group showed significantly lower mean values for Total Oxidant Status (TOS) (p = 0.002) and Oxidative Stress Index (OSI) (p = 0.007).

CONCLUSIONS

An intra-articular DZ injection appears to show limited reduction of oxidative damage and early OA in the rabbit TMJ. DZ might represent a promising natural compound with beneficial effects in the management of TMJ-OA.

Potential Impacts of Prolonged Face Mask Use on Temporomandibular Joint Health as Neglected Lifestyle Repercussions of COVID-19 Pandemic-A Narrative Review

Since December 2019, COVID-19 has rapidly spread worldwide, prompting the World Health Organization (WHO) to declare it a pandemic and advocate for the widespread use of face masks to mitigate transmission. In this review, we delve into the potential impact of prolonged face mask use on temporomandibular joint (TMJ) health, an area that has garnered limited attention amidst COVID-19 research. Research has revealed that improper mask fit and constant readjustment can lead to TMJ abnormalities. Similarly, there is a demonstrated correlation between continuous mask usage and an increased incidence of headaches, temporomandibular pain, and diminished quality of life. Many studies have highlighted discomfort in the preauricular area, headaches, TMJ noises, headache, jaw pain, and muscle fatigue, as well as dermatological disorders, which have been attributed to prolonged mask wear and its impact on TMJ health. Our study catalyzes future research endeavors, urging a deeper exploration of the implications of long-term mask wear, not only in the context of the COVID-19 pandemic but also among occupational groups regularly exposed to extended mask use. By unraveling the complexities of TMJ health in the face of evolving preventive measures, we aim to enhance our understanding of this issue and safeguard the well-being of mask-wearers worldwide.

The Difference in Electromyographic Activity While Wearing a Medical Mask in Women with and without Temporomandibular Disorders

Wearing a medical mask influences resting activity of the temporalis anterior and masseter muscles in healthy young women. However, no studies link medical mask-wearing with masticatory muscle activity in patients with temporomandibular disorders (TMDs). Therefore, this study aims to compare electromyographic patterns while wearing a medical mask between women with and without temporomandibular disorders. Based on the Research Diagnostic Criteria for Temporomandibular Disorders, 115 adult women qualified for the study. Participants were divided into the following two groups: diagnosed TMDs (n = 55; mean age: 23.5 ± 2.3 years) and healthy women (n = 60; mean age: 23.7 ± 2.6 years). Examinations of the resting and functional electromyographic activity of the temporalis anterior (TA), superficial masseter (MM), anterior bellies of the digastric muscle (DA), and the middle part of the sternocleidomastoid muscle (SCM) were carried out using the BioEMG III™. Both groups showed statistically significant decreases in resting masticatory muscle activity during medical mask examination compared to no mask measurement. The significant differences in no mask measurement between both groups were noted regarding resting masticatory activity, clenching in the intercuspal position, and clenching on dental cotton rollers. During medical mask examination, women with TMDs showed differences in resting masticatory activity and clenching on dental cotton rollers compared to the healthy group. In all analyzed variables, both groups showed similar electromyographic patterns in the maximum mouth opening measurement during medical mask and no mask examination. A medical mask influences the resting bioelectric activity of the masticatory muscles in women with temporomandibular disorders and healthy women. We observed differences and some similarities in resting and functional electromyographic patterns within masticatory and neck muscles in both groups during medical mask and no mask examination.

Measuring Changes in Jaw Opening Forces to Assess the Degree of Improvement in Patients with Temporomandibular Disorders

Background: Currently, the degree of improvement in patients with TMDs is measured through subjective questionnaires and clinical examination This study aimed to investigate the properties of an objective quantitative measure of jaw-opening forces to assess clinical improvement in temporomandibular disorder (TMD) patients following treatment. Methods: Baseline jaw-opening forces were recorded for TMD-patients (n = 62) and a comparison group of TMD-free participants (n = 56), using a jaw-opening forces measuring device. TMD patients were divided into three subcategories (myofascial pain, disc-displacement, and myofascial pain and disc-displacement combined) and received a combination of treatment for six months; meanwhile, TMD-free participants did not receive treatment. Jaw-opening forces for each participant in both groups were measured at their six-month review appointment. Results: Jaw-opening forces were reliable at baseline (single measure ICC 0.98, 95% CI 0.97–0.98, ICC ≥ 0.94 for all groups and subcategories). Jaw-opening forces increased in the TMD group following treatment at six-months (18.6 N at baseline and 32.4 N at six-months, p < 0.001) and did not change significantly in the TMD-free group (49 N at baseline and 48.3 N at six-months). There was a small improvement in the disc displacement group (27.8% higher forces, p = 0.002). However, the myofascial-pain and myofascial-pain-and-disc-displacement groups showed significant improvement following treatment (93.5% higher forces, p < 0.001; 91.1% higher forces, p < 0.001; respectively). Conclusion: This study demonstrated that the measurement of jaw-opening forces could potentially be used to assess the clinical improvement in TMD patients following diagnosis and treatment.

Electromyographic Patterns of Masticatory Muscles in Relation to Active Myofascial Trigger Points of the Upper Trapezius and Temporomandibular Disorders

The presented study aimed to analyze and compare the electromyographic patterns of masticatory muscles in subjects with active myofascial trigger points (MTrPs) within upper trapezius, patients with temporomandibular disorders (TMDs) and healthy adults. Based on the diagnostic criteria of MTrPs according to Travell & Simons and the Research Diagnostic Criteria for Temporomandibular Disorders, 167 people were qualified for the study. Subjects were divided into 3 groups: with active MTrPs in the upper trapezius, with diagnosed temporomandibular disorders (TMDs) and healthy adults. Measurements of the bioelectric activity of the temporalis anterior (TA) and masseter muscle (MM) were carried out using the BioEMG III ™. Based on statistical analysis, significantly lower values of TA resting activity were observed among controls in comparison to MTrPs (1.49 μV vs. 2.81 μV, p = 0.00) and TMDs (1.49 μV vs. 2.97 μV, p = 0.01). The POC index values at rest differed significantly between MTrPs and TMDs (86.61% vs. 105%, p = 0.04). Controls presented different electromyographic patterns within AcI in comparison to both MTrPs (4.90 vs. −15.51, p = 0.00) and TMDs (4.90 vs. −16.49, p = 0.00). During clenching, the difference between MTrPs and TMDs was observed within MVC TA (91.82% vs. 116.98%, p = 0.02). TMDs showed differences within AcI in comparison to both MTrPs group (−42.52 vs. 20.42, p = 0.01) and controls (−42.52 vs. 3.07, p = 0.00). During maximum mouth opening, differences between MTrPs and TMDs were observed within the bioelectric activity of masseter muscle (16.45 μV vs. 10.73 μV, p = 0.01), AsI MM (0.67 vs. 11.12, p = 0.04) and AcI (13.04 vs. −3.89, p = 0.01). Both the presence of MTrPs in the upper trapezius and TMDs are related to changes in electromyographic patterns of masticatory muscles.

Imaging of the temporomandibular joint

Temporomandibular disorders are common, especially in young to middle-aged women, and most settle with supportive treatment. Imaging is indicated for the small percentage of cases that do not respond to conservative management and when the diagnosis is no doubt. The temporomandibular joint (TMJ) is a bilateral synovial articulation between the mandible and skull base. It has an intra-articular disc dividing the joint into superior and inferior compartments and the articular surfaces are lined with fibrocartilage. The normal imaging anatomy of the TMJ is described and illustrated. Different movements occur in each joint compartments: a hinge movement in the inferior joint space and translation or gliding in the superior joint space. Internal derangement is the commonest disorder affecting the TMJ and is most commonly due to disc displacement, followed by osteoarthritis and inflammatory arthritides. The imaging findings, primarily on magnetic resonance imaging (MRI) and computed tomography (CT), of internal derangement and less common disorders of the joint, are reviewed and illustrated. Optimal imaging protocols are discussed with detailed reporting guidelines.

Photobiomodulation and Stem Cell Therapy for Temporomandibular Joint Disc Disorders

Background: Temporomandibular disorder (TMD) refers to a group of disorders affecting the temporomandibular joint (TMJ) and its related muscles. The two commonly used treatment modalities for TMD are occlusal splint therapy and relaxation therapy. Neither comprises definitive treatment. Objective: The objective of this review was to report updated information on photobiomodulation and stem cells, as an alternative treatment for the degenerative TMJ disc as a part of TMJ disorders. Materials and methods: With only a few research studies reported till date, this review also proposes the mechanism of laser irradiation on inflammatory mediators to treat TMD. Results: Photobiomodulation of stem cells with and without scaffolds could be used indirectly or directly as modulation of degenerative changes of the TMJ disc. Conclusions: The need for a distinct shift of the research margin in this field of dentistry is evident, specifically regarding the application of photobiomodulation and stem cells for tissue engineering of the TMJ disc.

Conservative therapy for the treatment of patients with somatic tinnitus attributed to temporomandibular dysfunction: study protocol of a randomised controlled trial

BACKGROUND

Tinnitus is a highly prevalent symptom affecting 10-15% of the adult population. It often affects patient quality of life and frequently causes distress. When subjective tinnitus can be elicited by the somatosensory system of the cervical spine or temporomandibular area it is termed somatic tinnitus. The first aim of the current study is to investigate the effect of the best evidence conservative temporomandibular disorder (TMD) treatment on tinnitus in patients with co-existence of tinnitus and TMD or oral parafunctions compared to no treatment. The second aim is to identify a subgroup of patients with tinnitus that benefits from the conservative temporomandibular joint treatment.

METHODS AND DESIGN

This study is a randomised controlled trial with a delayed treatment design. Patients with a TMD (TMD pain screener ≥ 3 points) or oral parafunctions (such as clenching and bruxism), who are suffering from moderate to severe subjective tinnitus (Tinnitus Functional Index (TFI) between 25 and 90 points), will be recruited from the tertiary tinnitus clinic of the University Hospital of Antwerp, Edegem, Belgium. Patients will be excluded in case of clear otological or neurological causes of the tinnitus, progressive middle ear pathology, intracranial pathology, traumatic cervical spine or temporomandibular injury in the past 6 months, severe depression as diagnosed by a psychologist, tumours, previous surgery in the orofacial area, substance abuse that may affect the outcome measures, any contra-indication for physical therapy treatment directed to the orofacial area or when they received TMD treatment in the past 2 months. After screening for eligibility, baseline data among which scores on the TFI, tinnitus questionnaire (TQ), mean tinnitus loudness as measured with visual analogue scale (VAS), TMD pain screener, and a set of temporomandibular joint tests will be collected. Patients will be randomised in an early-start group and in a delayed-start group of therapy by 9 weeks. Patients will receive conservative TMD treatment with a maximum of 18 sessions within 9 weeks. At baseline (week 0), at the start of therapy (weeks 0 or 9), 9 weeks after therapy (weeks 9 or 18), and at follow-up (weeks 18 or 27) data from the TFI, TQ, VAS mean tinnitus loudness and the TMD pain screener will be collected.

DISCUSSION

Herein, we aim to improve the quality of care for patients with tinnitus attributed to TMD or oral parafunctions. By evaluating the effect of state-of-the-art TMD treatment on tinnitus complaints, we can investigate the usefulness of TMD treatment in patients with somatic tinnitus.

TRIAL REGISTRATION

3 July 2017, version 1 of the protocol, ClinicalTrials.gov NCT03209297 .

Is the Anchored Disc Phenomenon a Truly Distinct Entity? A Systematic Review

PURPOSE

This review aimed to examine whether the anchored disc phenomenon (ADP) is truly a distinct entity, independent of the closed-lock condition attributed to nonreducible disc displacement.

MATERIALS AND METHODS

Clinical and/or diagnostic imaging studies addressing the anchored disc or ADP were considered. Articles eligible for inclusion were written in English; were conducted in humans; showed, in their titles or abstracts, any of the keywords used in the search method; included some type of disc imaging system; and related disc mobility to disc position. Of 18 potentially relevant articles, 10 were included.

RESULTS

Of the studies, 9 used magnetic resonance imaging and 1 used double-contrast cone-beam computed tomography. In 1,691 joints, 270 discs (16%) were shown to be anchored in a normal (41%) or displaced (59%) position. Of 149 displaced anchored discs, 52 were reducible and 97 were nonreducible. Intra-articular adherences, synovitis, and adhesions were common arthroscopic findings in patients with the ADP.

CONCLUSIONS

The temporomandibular joint anchored disc shown by disc imaging systems is worthy of inclusion in the existing categories of temporomandibular joint internal derangement. Classification of the ADP as a distinct entity still awaits a consensual definition of the problem, validation of the underlying hypothesis, and clarification of the natural history of the phenomenon.

Orofacial pain - an update on diagnosis and management

The diagnosis and management of orofacial pain may be challenging due to complex histories, pathophysiology and associated psychosocial co-morbidities such as depression and anxiety. Neuropathic facial pain conditions such as burning mouth syndrome (BMS), persistent idiopathic facial pain (PIFP), atypical odontalgia (AO) and trigeminal neuralgia (TN) require early recognition by primary care clinicians and referral to secondary care. Acute pain-related temporomandibular disorder (TMD) may be managed in the primary care setting, with identification of those at risk of developing chronic TMD receiving an early referral to secondary care. Adopting a biopsychosocial approach, consisting of physical therapies, pharmacotherapy and psychological support can lead to effective management and may limit the negative impact of facial pain upon quality of life and daily functioning.

Dental (Odontogenic) Pain

This article provides a simple overview of acute trigeminal pain for the non dentist.This article does not cover oral mucosal diseases (vesiculobullous disorders) that may cause acute pain.Dental pain is the most common in this group and it can present in several different ways.Of particular interest for is that dental pain can mimic both trigeminal neuralgia and other chronic trigeminal pain disorders.It is crucial to exclude these disorders whilst managing patients with chronic trigeminal pain.

Persistent Pain after Dental Surgery

This article aims to cover post surgical trigeminal neuropathy and other conditions related to chronic trigeminal pain not specifically covered elsewhere in this series.Is estimated to occur in 4-5% of patients overall, considerably less compared with other site surgeries.Due to the high volume surgery undertaken in this region chronic post surgical pain remains common.Relatively few clinicians are aware of this condition and as a result it is frequently poorly managed.

Timing interventions in relation to temporomandibular joint closed lock duration: a systematic review of 'locking duration'

Temporomandibular joint (TMJ) 'closed lock' (CL) is a clinical condition causing TMJ pain and limited mouth opening (painful locking) that is mostly attributed to disc displacement without reduction (DDwoR), or less commonly to anchored disc phenomenon (ADP). Both conditions are described clinically as CL that can be 'acute' or 'chronic' depending on the duration of locking. There is, however, no consensus about the duration of locking that defines the acute state and its effect on the success of interventions. This review paper, therefore, aims to provide: (i) a narrative review of the pathophysiological need for early intervention in DDwoR and the clinical implications of acute/chronic CL stages on the management pathway; (ii) a systematic review investigating the effects of locking duration on the success of interventions for CL management. Electronic and manual searches until mid-August 2013 were conducted for English-language studies of any design investigating the effects of non-surgical and surgical interventions for acute or chronic CL (DDwoR or ADP). A total of 626 records were identified, and 113 studies were included. Data extraction and quality assessment were completed for all included studies. Included studies were, however, heterogeneous and mostly of poor-quality leading to contradictory and inconsistent evidence on the effect of the duration of locking on treatment outcomes. Future high-quality trials investigating the effect of CL duration on treatment outcome are needed. At present, early intervention by 'unlock' mandibular manipulation seems to be the most practical and realistic approach that can be attempted first in every CL patient as an initial diagnostic/therapeutic approach.