Acute Temporomandibular Disorders Research Articles

Whole-genome methylation profiling reveals regions associated with painful temporomandibular disorders and active recovery processes.

Temporomandibular disorders (TMDs), collectively representing one of the most common chronic pain conditions, have a substantial genetic component, but genetic variation alone has not fully explained the heritability of TMD risk. Reasoning that the unexplained heritability may be because of DNA methylation, an epigenetic phenomenon, we measured genome-wide DNA methylation using the Illumina MethylationEPIC platform with blood samples from participants in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study. Associations with chronic TMD used methylation data from 496 chronic painful TMD cases and 452 TMD-free controls. Changes in methylation between enrollment and a 6-month follow-up visit were determined for a separate sample of 62 people with recent-onset painful TMD. More than 750,000 individual CpG sites were examined for association with chronic painful TMD. Six differentially methylated regions were significantly ( P < 5 × 10 -8 ) associated with chronic painful TMD, including loci near genes involved in the regulation of inflammatory and neuronal response. A majority of loci were similarly differentially methylated in acute TMD consistent with observed transience or persistence of symptoms at follow-up. Functional characterization of the identified regions found relationships between methylation at these loci and nearby genetic variation contributing to chronic painful TMD and with gene expression of proximal genes. These findings reveal epigenetic contributions to chronic painful TMD through methylation of the genes FMOD , PM20D1 , ZNF718 , ZFP57 , and RNF39 , following the development of acute painful TMD. Epigenetic regulation of these genes likely contributes to the trajectory of transcriptional events in affected tissues leading to resolution or chronicity of pain.

The contribution of pain and disability on the transition from acute to chronic pain-related TMD: A 3-month prospective cohort study.

Although most cases of pain-related temporomandibular disorders (TMD) are mild and self-limiting, about 10% of TMD patients develop severe disorders associated with chronic pain and disability. It has been suggested that pain intensity contributes to the transition from acute to chronic pain-related TMD. Therefore, the aims of this current prospective cohort study were to assess if pain intensity, pain always being present, pain or stiffness on awakening, jaw activities, and interference, were associated with the transition from acute to chronic pain-related TMD at 3 months of follow-up. One hundred and nine participants, recruited from four clinics in Montreal and Ottawa, received examinations and completed the required instruments at baseline and at the 3rd month of follow-up. In a multivariable analysis including sex, age, characteristic pain index (CPI) (OR = 1.03, 95%CI = 1.01–1.06, P = 0.005), moderate to severe average pain intensity (OR = 3.51, 95%CI = 1.24–9.93, P = 0.02), disability points score (OR = 1.29, 95%CI = 1.06–1.57, P = 0.01), interferences (ORs = 1.30–1.32, P = 0.003–0.005), screening score (OR = 1.37, 95%CI = 1.08–1.76, P = 0.01), and pain always present (OR = 2.55, 95%CI = 1.08–6.00, P = 0.03) assessed at first-visit were related to the transition outcome at the 3rd month of follow-up. Further, we found that if 4 patients with acute pain-related TMD on average were exposed to these risk factors at baseline, 1 would have the transition from acute to chronic pain at 3 months of follow-up. Results indicate that these factors are associated with the transition from acute to chronic pain-related TMD, and therefore should be considered as important factors when evaluating and developing treatment plans for patients with pain-related TMD.

Effectiveness of manual therapy applied to craniomandibular structures in temporomandibular disorders: A systematic review.

Within physical therapy, manual therapy is known to be effective for managing temporomandibular disorders (TMDs). However, manual therapy is a broad term including different approaches applied to different body regions. This is the first systematic review that aims to evaluate the effectiveness of manual therapy applied specifically to the craniomandibular structures (Cranio-Mandibular Manual Therapy [CMMT]) on pain and maximum mouth opening in people with TMD. This systematic review was developed based on a pre-determined published protocol which was prospectively registered with PROSPERO (CRD42019160213). A search of MEDLINE, Embase, CINAHL, ZETOC, Web of Science, SCOPUS, PEDro, PubMed, Cochrane Library and Best Evidence, EBM reviews-Cochrane Central Register of Controlled Trials, Index to Chiropractic Literature ChiroAccess and Google Scholar databases was conducted from inception until October 2020. Randomised controlled trials comparing the effect of CMMT on pain and maximum mouth opening versus other types of treatment in TMDs were included. Two reviewers independently screened articles for inclusion, extracted data, assessed risk of bias with the revised Cochrane risk of bias tool for randomised trials and evaluated the overall quality of evidence with the Grading of Recommendations, Assessment, Development and Evaluations. A total of 2720 records were screened, of which only 6 (293 participants) satisfied the inclusion criteria. All studies showed some concerns in risk of bias, except for one, which was high risk of bias. The overall quality of evidence was very low for all outcomes because of high heterogeneity and small sample sizes. All studies showed a significant improvement in pain and maximum mouth opening for CMMT from baseline in the mid-term, but only two showed superiority compared to other interventions. Given the high heterogeneity and small sample sizes of the included studies, a quantitative synthesis was not performed. There is the need for future high methodology research investigating different manual therapy techniques applied to different regions and different populations (e.g., chronic versus acute TMD) to determine what is most effective for pain and maximum mouth opening in patients with TMDs.

Acute and Chronic Temporomandibular Disorder Pain: A critical review of differentiating factors and predictors of acute to chronic pain transition.

The aims of this critical review were to: (i) assess the factors that differentiate acute from chronic temporomandibular disorders (TMD) pain; (ii) assess the risk factors associated with the transition from acute to chronic TMD pain; and (iii) summarize and appraise the studies. The databases used were MEDLINE, Embase, and Cochrane Database of Systematic Reviews. Eligible studies included articles comparing acute to chronic TMD pain, and cohort studies assessing the risk factors implicated in the transition from acute to chronic TMD pain. Seven articles were selected: one case-control study, three cross-sectional studies, and three cohort studies. These studies found that psychological factors were more common in chronic than acute TMD pain patients; however, these factors did not increase the transition risk in the multivariable model. Myofascial and baseline pain intensity were associated with the transition from acute to chronic TMD pain at a 6-month follow-up. Due to methodological weaknesses in the available literature, more research is required to establish the risk factors implicated in the transition from acute to chronic TMD pain. This review found some evidence that myofascial pain is associated with the transition risk from acute to chronic TMD pain at a 6-month follow-up and that pain intensity at baseline is associated with more intense TMD pain 6months later. There is insufficient evidence to draw conclusions about the role of demographics and psychological disorders as independent risk factors.

Oral health–related quality of life of patients with acute and chronic temporomandibular disorder diagnostic subtypes

BackgroundStudies have indicated the negative effects of temporomandibular disorders (TMDs) on oral health–related quality of life (OHRQoL). The authors investigated the OHRQoL of patients with acute and chronic TMD subtypes. MethodsThe authors recruited a total of 830 patients. They derived TMD diagnoses using the Diagnostic Criteria for TMDs protocol involving symptom history, physical examination, and diagnostic imaging as indicated. The authors categorized patients into acute (≤ 3 months) or chronic (> 3 months) pain-related TMD (PT), nonpainful intra-articular TMD (IT), and combined TMD (CT) groups. They also gathered sociodemographic information and assessed OHRQoL with the Oral Health Impact Profile (OHIP)-TMDs. The authors evaluated data using 2-way analysis of variance and Bonferroni test and multiple regression analysis. ResultsPatients in the chronic PT and CT subgroups had significantly higher mean global OHIP scores than their acute counterparts. The authors observed significant acute-chronic differences in OHIP-TMDs domain scores in 5 and 2 domains for the PT and CT groups, respectively. Patients in the acute IT group had significantly higher functional limitation scores than those in the chronic IT group. The ranking of mean global scores, in descending order was CT, PT, and IT for acute TMDs and PT, CT, and IT for chronic TMDs, with significant differences observed among the 3 TMD subtypes (P < .001). ConclusionsBoth TMD chronicity and subtypes influenced OHRQoL. Painful TMDs (PT and CT) were associated with significantly poorer OHRQoL than nonpainful TMDs. TMD chronicity appeared to affect OHRQoL only for the painful TMD conditions. Future work on the impact of TMDs on OHRQoL should strive to stratify patients by TMD chronicity and subtypes. Practical ImplicationsTMD chronicity and subtypes influence the impact of TMDs on OHRQoL. Given that chronic painful TMDs impair quality of life, early biopsychosocial intervention of acute TMD pain is important for minimizing chronification and OHRQoL deterioration.

Laser phototherapy in acute posttraumatic trismus - Case-series study.

There are very few studies on laser phototherapy (LPT) in acute temporomandibular disorders (TMDs). Our objective is to assess the effectiveness of laser phototherapy (LPT) on the limitation of the mouth opening due to an acute mandibular trauma. Fourteen women of 41 ± 3 years and 24 men of 38 ± 3 years, with no history of TMD and having sustained a mandibular trauma within the prior 20 hours, were treated exclusively by using an 810-nm laser beam in a continuous wave mode, with an output power of 1 W. At a speed of 2 cm/s, it scanned twice, for 60 seconds, with a pause in between of 2 minutes, a large cutaneous area (25 cm2), covering the temporomandibular joint (TMJ), the masseter muscle and a part of the temporalis fossa; also, it scanned just once, for 7 seconds, a small mucous area (3 cm2), covering the internal pterygoid muscle. The clinical outcomes were evaluated by comparing the maximum unassisted opening (MUO), measured at the baseline and immediately after the end of the LPT procedure. The MUO improvement of 24.6 ± 4.4 mm represented a highly significant difference (p < .0001) between the measurements, in all the patients, regardless of gender. By scanning with an 810-nm laser beam, within less than 20 hours after the trauma, large areas of all the involved tissues and not just a few points, as described until now, the limited mouth opening in acute posttraumatic trismus was immediately and greatly resolved.

A potent and selective calcitonin gene-related peptide (CGRP) receptor antagonist, MK-8825, inhibits responses to nociceptive trigeminal activation: Role of CGRP in orofacial pain

Temporomandibular disorders (TMDs) are orofacial pains within the trigeminal distribution, which involve the masticatory musculature, the temporomandibular joint or both. Their pathophysiology remains unclear, as inflammatory mediators are thought to be involved, and clinically TMD presents pain and sometimes limitation of function, but often appears without gross indications of local inflammation, such as visible edema, redness and increase in temperature. Calcitonin gene-related peptide (CGRP) has been implicated in other pain disorders with trigeminal distribution, such as migraine, of which TMD shares a significant co-morbidity. CGRP causes activation and sensitization of trigeminal primary afferent neurons, independent of any inflammatory mechanisms, and thus may also be involved in TMD. Here we used a small molecule, selective CGRP receptor antagonist, MK-8825, to dissect the role of CGRP in inducing spontaneous nociceptive facial grooming behaviors, neuronal activation in the trigeminal nucleus, and systemic release of pro-inflammatory cytokines, in a mouse model of acute orofacial masseteric muscle pain that we have developed, as a surrogate of acute TMD. We show that CFA masseteric injection causes significant spontaneous orofacial pain behaviors, neuronal activation in the trigeminal nucleus, and release of interleukin-6 (IL-6). In mice pre-treated with MK-8825 there is a significant reduction in these spontaneous orofacial pain behaviors. Also, at 2 and 24h after CFA injection the level of Fos immunoreactivity in the trigeminal nucleus, used as a marker of neuronal activation, was much lower on both ipsilateral and contralateral sides after pre-treatment with MK-8825. There was no effect of MK-8825 on the release of IL-6. These data suggest that CGRP may be involved in TMD pathophysiology, but not via inflammatory mechanisms, at least in the acute stage. Furthermore, CGRP receptor antagonists may have therapeutic efficacy in the treatment of TMD, as they do with migraine.

Laser acupuncture therapy in patients with treatment-resistant temporomandibular disorders.

ObjectiveTo investigate the clinical effects of laser acupuncture therapy for temporomandibular disorders (TMD) after ineffective previous treatments.MethodsA retrospective observational study was conducted in 29 treatment-resistant TMD patients (25 women, 4 men; age range, 17–67 years). Subjects were treated 3 times per week for 4 weeks with the Handylaser Trion (GaAlAs laser diode, 810 nm, 150 mW, pulsed waves), which delivered 0.375 J of energy (5 s) to ST7, ST6, and LI4 and 3 J (40 s) to each Ashi point, 7.5–26.25 J/cm2 in total. The visual analog scale (VAS) and maximal mouth opening (MMO) were evaluated before and after treatment.ResultsVAS analysis showed that the patients were free of pain at rest (endpoint) after 5.90±6.08 sessions of laser acupuncture for acute TMD and after 16.21±17.98 sessions for chronic TMD. The VAS score on palpation of the temporomandibular joint reduced to 0.30±0.67 for patients with acute TMD (p = 0.005) and to 0.47±0.84 for those with chronic TMD (p<0.001). The MMO significantly increased in patients with acute TMD (7.80±5.43 mm, p = 0.008) and in patients with chronic TMD (15.58±7.87 mm, p<0.001).ConclusionsOur study shows that laser acupuncture therapy improves the symptoms of treatment-resistant TMD. Further studies with a more appropriate design, involving long-term follow-up examinations in a larger patient sample, are needed to evaluate its efficacy.

Evaluation of low-level laser therapy in patients with acute and chronic temporomandibular disorders

The purpose of this study was to address the following question: among patients with acute or chronic temporomandibular disorders (TMD), does low-level laser therapy (LLLT) reduce pain intensity and improve maximal mouth opening? The sample comprised myogenic TMD patients (according Research Diagnostic Criteria for TMD). Inclusion criteria were: male/female, no age limit, orofacial pain, tender points, limited jaw movements and chewing difficulties. Patients with other TMD subtypes or associated musculoskeletal/rheumatologic disease, missing incisors teeth, LLLT contra-indication, and previous TMD treatment were excluded. According to disease duration, patients were allocated into two groups, acute (<6 months) and chronic TMD (≥ 6 months). For each patient, 12 LLLT sessions were performed (gallium-aluminum-arsenide; λ = 830 nm, P = 40 mW, CW, ED = 8 J/cm(2)). Pain intensity was recorded using a 10-cm visual analog scale and maximal mouth opening using a digital ruler (both recorded before/after LLLT). The investigators were previously calibrated and blinded to the groups (double-blind study) and level of significance was 5% (p < 0.05). Fifty-eight patients met all criteria, 32 (acute TMD), and 26 (chronic TMD). Both groups had a significant pain intensity reduction and maximal mouth opening improvement after LLLT (Wilcoxon test, p < 0.001). Between the groups, acute TMD patient had a more significant pain intensity reduction (Mann-Whitney test, p = 0.002) and a more significant maximal mouth opening improvement (Mann-Whitney test, p = 0.011). Low-level laser therapy can be considered as an alternative physical modality or supplementary approach for management of acute and chronic myogenic temporomandibular disorder; however, patients with acute disease are likely to have a better outcome.

Clinical implications of sex in acute temporomandibular disorders

Previous research on temporomandibular disorders, or TMDs, has been somewhat limited, with studies having low numbers of subjects, restricting the focus to women or looking at patients already diagnosed with chronic TMD. Because early intervention is beneficial, it is important to understand the symptoms that men and women have in the acute stage of TMD. A total of 233 patients (161 women, 72 men) with acute TMD symptoms were assessed with a battery of biopsychosocial measures. Patients were diagnosed as having TMD on the basis of research diagnostic criteria, or RDC, or RDC, for TMD. After six months, patients were reassessed to determine whether they continued to have pain, thus classifying them as having chronic TMD. The authors found that 153 patients (47 men, 106 women) had developed a chronic condition, while 80 patients (25 men, 55 women) no longer reported pain (nonchronic). Female and male patients who developed chronic TMD differed significantly from patients who had acute symptoms that subsided. Women who developed chronic TMD exhibited significantly more psychosocial distress and impairment than women who did not develop chronic TMD, in terms of Diagnostic and Statistical Manual, Fourth Edition, or DSM-IV, diagnoses; Beck Depression Inventory, or BDI, scores; Minnesota Multiphasic Personality Inventory scores; Multidimensional Pain Inventory, or MPI, scores; and physical and psychological measures assessed with the RDC for TMD. Men who developed chronic TMD differed significantly from men who did not develop chronic TMD, in that they exhibited more impairment in terms of DSM-IV diagnoses and BDI and RDC measures. These findings provide evidence that significant differences exist between men and women in regard to acute TMD symptoms. The biopsychosocial differences between men and women suggest that some treatments may be more beneficial for women than for men.

Pain mechanisms in myogenous temporomandibular disorders

Myogenous pain associated with temporomandibular disorders (TMDs) has traditionally been linked to hyperactivity or abnormal contraction of masticatory muscles. The evidence in the literature for a reinforcing vicious cycle between muscle hyperactivity and pain has, however, been critically reviewed and cannot confirm all previous beliefs. In the absence of identifiable tissue pathology, another common idea has been that myogenous pain is a psychological or psychosomatic disorder, but research results may now be able to explain TMD pain from a more neurobiologic perspective. Based on present knowledge, new appealing hypotheses regarding pathophysiologic reactions in acute and chronic myogenous TMD pain can be formulated. Facing the many controversies in the TMD literature, the challenge of this article is to provide a short status of suggested pain mechanisms. It will be argued that different subtypes of myogenous TMDs have distinct pathophysiologic characteristics with increasing levels of complexity as the pain persists: acute TMD pain is the result of primarily peripheral problems, whereas chronic TMD pain is a central problem with plastic neural changes at the trigeminal level and impairment of endogenous pain regulatory systems.

New TMJ Clinical Data and the Implication on Diagnosis and Treatment

A review of the literature and the presentation of 220 patients with acute temporomandibular disorders and a control group are presented. Condylar position in the fossae is related to clinical symptoms. Ten important clinical factors were recorded and the data compared without reference to specific condylar position in the fossae and then in relation to condylar displacement groups. The significantly high incidence of posterior condylar displacement and joint pain in the patients described in this report indicates that elimination of the term joint in our definition of this disorder may be premature.