Pharmacological interventions for pain in patients with temporomandibular disorders

Effect of propranolol on temporomandibular joint pain in repeatedly stressed rats

Stress substantially increases the risk of developing painful temporomandibular disorders (TMDs) by influencing the release of endogenous catecholamines. Propranolol, an antagonist of β-adrenergic receptors, has shown potential in alleviating TMD-associated pain, particularly when the level of catecholamines is elevated. The aim of this study was to explore whether intra-articular propranolol administration is effective in diminishing temporomandibular joint (TMJ) pain during repeated stress situations. Additionally, we investigated the effect of repeated stress on the expression of genes encoding β-adrenoceptors in the trigeminal ganglion. In the present study, rats were exposed to a stress protocol induced by sound, then to the administration of formalin in the TMJ (to elicit a nociceptive response), followed immediately afterward by different doses of propranolol, after which the analgesic response to propranolol was evaluated. We also assessed the levels of beta-1 and beta-2 adrenergic receptor mRNAs (Adrb1 and Adrb2, respectively) using reverse transcription-quantitative PCR (RT-qPCR). Our findings revealed that propranolol administration reduces formalin-induced TMJ nociception more effectively in stressed rats than in non-stressed rats. Furthermore, repeated stress decreases the expression of the Adrb2 gene within the trigeminal ganglion. The findings of this study are noteworthy as they suggest that individuals with a chronic stress history might find potential benefits from β-blockers in TMD treatment.

Pharmacological therapy in the management of temporomandibular disorders and orofacial pain: a systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMD) are manifested by soreness in the jaw joint area and jaw muscles, clicks or creaks when opening or closing the mouth. All these symptoms can be disabling and occur during chewing and when the patient yawns or speaks. Several classes of drugs are used to treat symptoms. This review aims to assess which drug suits the different signs.

METHODS

Pubmed, Web of Science and Lilacs were systematically searched until 01/02/2023. Clinical trials were selected that dealt with drugs used in temporomandibular dysfunction RESULTS: Out of 830 papers, eight studies were included. The Meta-Analysis with Continuous Outcomes with Pre-Calculated Effect Sizes resulted in the rejection that there is intergroup variability (p.0.74).

CONCLUSIONS

Treatment of orofacial pain is still a significant challenge for dentistry. We can conclude that there is no drug of first choice in the treatment of temporomandibular pain. However, the clinician must distinguish the type of pain and the aetioloic cause of the pain so that the patient can be treated and managed pharmacologically.

Recommendations on the Use of Oral Orthotic Occlusal Appliance Therapy for Temporomandibular Joint Disorders: Current Evidence and Clinical Practice

Background

'Temporomandibular joint disorders (TMDs)' denote an umbrella term that includes arthritic, musculoskeletal and neuromuscular conditions involving the temporomandibular joint, the masticatory muscles, and the associated tissues. Occlusal devices are one of the common treatment modalities utilized in the conservative management of TMDs. The indications for the available 'oral splints' or 'oral orthotic occlusal devices' remain ambiguous.

Methods

A joint international consortium was formulated involving the subject experts at TMJ Foundation, to resolve the current ambiguity regarding the use of oral orthotic occlusal appliance therapy for the temporomandibular joint disorders based on the current scientific and clinical evidence.

Results

The recommendations and the conclusion of the clinical experts of the joint international consort has been summarized for understanding the indications of the various available oral orthotic occlusal appliances and to aid in the future research on oral occlusal orthotics.

Conclusion

The use of the oral orthotic occlusal appliances should be based on the current available scientific evidence, rather than the archaic protocols.

Near-Infrared Light-Activated Mesoporous Polydopamine for Temporomandibular Joint Osteoarthritis Combined Photothermal-Chemo Therapy

The treatments generally employed for temporomandibular joint osteoarthritis (TMJOA) involve physical therapy and chemotherapy, etc., whose therapeutic efficacies are impaired by the side effects and suboptimal stimulus responsiveness. Although the intra-articular drug delivery system (DDS) has shown effectiveness in addressing osteoarthritis, there is currently little reported research regarding the use of stimuli-responsive DDS in managing TMJOA. Herein, we prepared a novel near-infrared (NIR) light-sensitive DDS (DS-TD/MPDA) by using mesoporous polydopamine nanospheres (MPDA) as NIR responders and drug carriers; diclofenac sodium (DS) as the anti-inflammatory medication; and 1-tetradecanol (TD) with a phase-inversion temperature of 39 °C as the drug administrator. Upon exposure to 808 nm NIR laser, DS-TD/MPDA could raise the temperature up to the melting point of TD through photothermal conversion, and intelligently trigger DS release. The resultant nanospheres exhibited an excellent photothermal effect and effectively controlled the release of DS through laser irradiation to accommodate the multifunctional therapeutic effect. More importantly, the biological evaluation of DS-TD/MPDA for TMJOA treatment was also performed for the first time. The experiments' results demonstrated that DS-TD/MPDA displayed a good biocompatibility in vitro and in vivo during metabolism. After injection into the TMJ of rats afflicted with TMJOA induced by unilateral anterior crossbite for 14 days, DS-TD/MPDA could alleviate the deterioration of TMJ cartilage, thus ameliorating osteoarthritis. Therefore, DS-TD/MPDA could be a promising candidate for photothermal-chemotherapy for TMJOA.

High-dose opioids for chronic non-cancer pain: an overview of Cochrane Reviews

BACKGROUND

This overview was originally published in 2017, and is being updated in 2022.  Chronic pain is typically described as pain on most days for at least three months. Chronic non-cancer pain (CNCP) is any chronic pain that is not due to a malignancy. Chronic non-cancer pain in adults is a common and complex clinical issue, for which opioids are prescribed by some physicians for pain management. There are concerns that the use of high doses of opioids for CNCP lacks evidence of effectiveness, and may increase the risk of adverse events.

OBJECTIVES

To describe the evidence from Cochrane Reviews and overviews regarding the efficacy and safety of high-dose opioids (defined as 200 mg morphine equivalent or more per day) for CNCP.

METHODS

We identified Cochrane Reviews and overviews by searching the Cochrane Database of Systematic Reviews in The Cochrane Library. The date of the last search was 21 July 2022. Two overview authors independently assessed the search results. We planned to analyse data on any opioid agent used at a high dose for two weeks or more for the treatment of CNCP in adults.

MAIN RESULTS

We did not identify any reviews or overviews that met the inclusion criteria. The excluded reviews largely reflected low doses or titrated doses, where all doses were analysed as a single group; we were unable to extract any data for high-dose use only.

AUTHORS' CONCLUSIONS

There is a critical lack of high-quality evidence, in the form of Cochrane Reviews, about how well high-dose opioids work for the management of CNCP in adults, and regarding the presence and severity of adverse events.  No evidence-based argument can be made on the use of high-dose opioids, i.e. 200 mg morphine equivalent or more daily, in clinical practice. Considering that high-dose opioids have been, and are still being used in clinical practice to treat CNCP, knowing about the efficacy and safety of these higher doses is imperative.

Effects of an Interdisciplinary Approach in the Management of Temporomandibular Disorders: A Scoping Review

Temporomandibular disorders (TMD) is an umbrella term that encompasses many musculoskeletal problems that include the masticatory muscles, the temporomandibular joint, and other associated structures. TMD can be divided into two large groups: those that affect the musculature and those that affect the joint. The treatment of TMD requires the combined skills of physiotherapists and dentists, as well as sometimes psychologists and other medical specialists. This study aims to examine the effectiveness of the interdisciplinary approach using physiotherapy and dental techniques on pain in patients with temporomandibular disorders (TMDs). This is a Scoping Review of studies investigating the effects of combined therapy on patients with TMD. PRISMA guidelines were followed during this review's design, search, and reporting stages. The search was carried out in the MEDLINE, CINHAL, and EMBASE databases. A total of 1031 studies were detected and analyzed by performing the proposed searches in the detailed databases. After removing duplicates and analyzing the titles and abstracts of the remaining articles, six studies were ultimately selected for this review. All the included studies showed a positive effect on pain decreasing after a combined intervention. The interdisciplinary approach characterized by the combination of manual therapy and splint or electrotherapy can positively influence the perceived symptoms; positively decrease pain; and reduce disability, occlusal impairments, and perception of change.

CDC Clinical Practice Guideline for Prescribing Opioids for Pain - United States, 2022

This guideline provides recommendations for clinicians providing pain care, including those prescribing opioids, for outpatients aged ≥18 years. It updates the CDC Guideline for Prescribing Opioids for Chronic Pain - United States, 2016 (MMWR Recomm Rep 2016;65[No. RR-1]:1-49) and includes recommendations for managing acute (duration of <1 month), subacute (duration of 1-3 months), and chronic (duration of >3 months) pain. The recommendations do not apply to pain related to sickle cell disease or cancer or to patients receiving palliative or end-of-life care. The guideline addresses the following four areas: 1) determining whether or not to initiate opioids for pain, 2) selecting opioids and determining opioid dosages, 3) deciding duration of initial opioid prescription and conducting follow-up, and 4) assessing risk and addressing potential harms of opioid use. CDC developed the guideline using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Recommendations are based on systematic reviews of the scientific evidence and reflect considerations of benefits and harms, patient and clinician values and preferences, and resource allocation. CDC obtained input from the Board of Scientific Counselors of the National Center for Injury Prevention and Control (a federally chartered advisory committee), the public, and peer reviewers. CDC recommends that persons with pain receive appropriate pain treatment, with careful consideration of the benefits and risks of all treatment options in the context of the patient's circumstances. Recommendations should not be applied as inflexible standards of care across patient populations. This clinical practice guideline is intended to improve communication between clinicians and patients about the benefits and risks of pain treatments, including opioid therapy; improve the effectiveness and safety of pain treatment; mitigate pain; improve function and quality of life for patients with pain; and reduce risks associated with opioid pain therapy, including opioid use disorder, overdose, and death.

Pain Management and Rehabilitation for Central Sensitization in Temporomandibular Disorders: A Comprehensive Review

Temporomandibular disorders (TMD) are a group of musculoskeletal diseases affecting masticatory muscles and temporomandibular joints (TMJ). In this context, the chronic TMD could be considered as a condition with chronic primary orofacial pain, presenting as myofascial TMD pain or TMJ arthralgia. In this context, myogenous TMD may present overlapping features with other disorders, such as fibromyalgia and primary headaches, characterized by chronic primary pain related to dysfunction of the central nervous system (CNS), probably through the central sensitization. This phenomenon could be defined as an amplified response of the CNS to sensory stimuli and peripheral nociceptive, characterized by hyperexcitability in the dorsal horn neurons in the spinal cord, which ascend through the spinothalamic tract. The main objectives of the management of TMD patients are: decreasing pain, increasing TMJ function, and reducing the reflex masticatory muscle spasm/pain. The first-line treatments are physical therapy, pharmacological drugs, occlusal splints, laser therapy, extracorporeal shockwave therapy, transcutaneous electrical nerve stimulation, and oxygen–ozone therapy. Although all these therapeutic approaches were shown to have a positive impact on the central sensitization of TMD pain, there is still no agreement on this topic in the scientific literature. Thus, in this comprehensive review, we aimed at evaluating the evidence on pain management and rehabilitation for the central sensitization in TMD patients.

Psychological therapies for temporomandibular disorders (TMDs)

BACKGROUND

Temporomandibular disorders (TMDs) are a group of musculoskeletal disorders affecting the jaw. They are frequently associated with pain that can be difficult to manage and may become persistent (chronic). Psychological therapies aim to support people with TMDs to manage their pain, leading to reduced pain, disability and distress.

OBJECTIVES

To assess the effects of psychological therapies in people (aged 12 years and over) with painful TMD lasting 3 months or longer.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched six bibliographic databases up to 21 October 2021 and used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of any psychological therapy (e.g. cognitive behaviour therapy (CBT), behaviour therapy (BT), acceptance and commitment therapy (ACT), mindfulness) for the management of painful TMD. We compared these against control or alternative treatment (e.g. oral appliance, medication, physiotherapy).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We reported outcome data immediately after treatment and at the longest available follow-up. We used the Cochrane RoB 1 tool to assess the risk of bias in included studies. Two review authors independently assessed each included study for any risk of bias in sequence generation, allocation concealment, blinding of outcome assessors, incomplete outcome data, selective reporting of outcomes, and other issues. We judged the certainty of the evidence for each key comparison and outcome as high, moderate, low or very low according to GRADE criteria.

MAIN RESULTS

We identified 22 RCTs (2001 participants), carried out between 1967 and 2021. We were able to include 12 of these studies in meta-analyses. The risk of bias was high across studies, and we judged the certainty of the evidence to be low to very low overall; further research may change the findings. Our key outcomes of interest were: pain intensity, disability caused by pain, adverse events and psychological distress. Treatments varied in length, with the shortest being 4 weeks. The follow-up time ranged from 3 months to 12 months. Most studies evaluated CBT.   At treatment completion, there was no evidence of a benefit of CBT on pain intensity when measured against alternative treatment (standardised mean difference (SMD) 0.03, confidence interval (CI) -0.21 to 0.28; P = 0.79; 5 studies, 509 participants) or control (SMD -0.09, CI -0.30 to 0.12; P = 0.41; 6 studies, 577 participants). At follow-up, there was evidence of a small benefit of CBT for reducing pain intensity compared to alternative treatment (SMD -0.29, 95% CI -0.50 to -0.08; 5 studies, 475 participants) and control (SMD -0.30, CI -0.51 to -0.09; 6 studies, 639 participants). At treatment completion, there was no evidence of a difference in disability outcomes (interference in activities caused by pain) between CBT and alternative treatment (SMD 0.15, CI -0.40 to 0.10; P = 0.25; 3 studies, 245 participants), or between CBT and control/usual care (SMD 0.02, CI -0.21 to 0.24; P = 0.88; 3 studies, 315 participants). Nor was there evidence of a difference at follow-up (CBT versus alternative treatment: SMD -0.15, CI -0.42 to 0.12; 3 studies, 245 participants; CBT versus control: SMD 0.01 CI - 0.61 to 0.64; 2 studies, 240 participants). There were very few data on adverse events. From the data available, adverse effects associated with psychological treatment tended to be minor and to occur less often than in alternative treatment groups. There were, however, insufficient data available to draw firm conclusions. CBT showed a small benefit in terms of reducing psychological distress at treatment completion compared to alternative treatment (SMD -0.32, 95% CI -0.50 to -0.15; 6 studies, 553 participants), which was maintained at follow-up (SMD -0.32, 95% CI -0.51 to -0.13; 6 studies, 516 participants). For CBT versus control, only one study reported results for distress and did not find evidence of a difference between groups at treatment completion (mean difference (MD) 2.36, 95% CI -1.17 to 5.89; 101 participants) or follow-up (MD -1.02, 95% CI -4.02 to 1.98; 101 participants). We assessed the certainty of the evidence to be low or very low for all comparisons and outcomes. The data were insufficient to draw any reliable conclusions about psychological therapies other than CBT.

AUTHORS' CONCLUSIONS

We found mixed evidence for the effects of psychological therapies on painful temporomandibular disorders (TMDs). There is low-certainty evidence that CBT may reduce pain intensity more than alternative treatments or control when measured at longest follow-up,  but not at treatment completion. There is low-certainty evidence that CBT may be better than alternative treatments, but not control, for reducing psychological distress at treatment completion and follow-up. There is low-certainty evidence that CBT may not be better than other treatments or control for pain disability outcomes.  There is insufficient evidence to draw conclusions about alternative psychological therapeutic approaches, and there are insufficient data to be clear about adverse effects that may be associated with psychological therapies for painful TMD.  Overall, we found insufficient evidence on which to base a reliable judgement about the efficacy of psychological therapies for painful TMD. Further research is needed to determine whether or not psychological therapies are effective, the most effective type of therapy and delivery method, and how it can best be targeted. In particular, high-quality RCTs conducted in primary care and community settings are required, which evaluate a range of psychological approaches against alternative treatments or usual care, involve both adults and adolescents, and collect measures of pain intensity, pain disability and psychological distress until at least 12 months post-treatment.

High Pain Intensity is a Risk Factor of Non-Resolving TMD: A Three-Year Follow-Up of a Patient Group in a Norwegian Interdisciplinary Evaluation Program

Purpose

To investigate the outcome of patients with long-term refractory temporomandibular disorders (TMD) three years after a Norwegian interdisciplinary evaluation program with attention to patient satisfaction, function, pain, and psychosocial variables.

Patients and Methods

The study population consisted of 60 long-term refractory TMD patients who were investigated by a Norwegian interdisciplinary team. A questionnaire that covered medical history, function, pain, lifestyle factors, TMD-status and follow-up from their general medical practitioner (GMP) was sent to the patients three years after the evaluation. Questionnaires that assessed function (Mandibular Functional Index Questionnaire [MFIQ] and Roland Morrison Scale [RMS]), pain intensity (General Pain Intensity questionnaire [GPI]) and psychosocial factors (Hospital Anxiety and Depression scale [HADS]); a 2-item version of the Coping Strategies Questionnaire [CSQ]) were included in the package.

Results

Thirty-nine out of 60 TMD patients completed the questionnaires. Improvements in TMD symptoms were reported in 10 patients (26%), were unchanged in 16 patients (41%) and worsened in 13 patients (33%). Only 8 patients (21%) were satisfied with the follow-up of the suggested treatments from their GMP. Significant improvements of symptoms were noted in MFIQ (jaw function), GPI (including pain intensity at maximum and suffering from pain), and CSQ (pain related catastrophizing), in all 39 TMD patients as one group. However, a subgroup analysis showed that the significant improvements were mostly within patients who reported improvement of TMD symptoms. A high pain intensity at baseline was a significant risk factor (OR = 5.79, 95% CI: 1.34, 24.96) for patients who reported worsening of TMD symptoms at follow-up.

Conclusion

High pain intensity at baseline was a significant risk factor for poorer recovery three years after an interdisciplinary evaluation. Our data support the notion that improved coping with TMD pain includes both decreased pain intensity, CSQ and MFIQ scores.

Role of Photobiomodulation Therapy in Modulating Oxidative Stress in Temporomandibular Disorders. A Systematic Review and Meta-Analysis of Human Randomised Controlled Trials

This systematic review and meta-analysis (PROSPERO registration; ref CRD 42020198921) aimed to govern photobiomodulation therapy (PBMT) efficacy in temporomandibular disorder (TMD). PRISMA guidelines and Cochrane Collaboration recommendations were followed. Differences in pain reduction assessment by qualitative measurement with visual analogue scale pain (VAS), pressure threshold (PPT) and maximum mouth opening (MMO) were calculated with 95% confidence intervals and pooled in a random effects model with a subgroup analysis, evaluating the role of follow-up duration. Heterogeneity was analysed using Q and I² tests. Publication bias was assessed by visual examination of funnel plot symmetry. Qualitative analysis revealed 46% of the 44 included studies showed a high risk of bias. Meta-analysis on 32 out of 44 studies revealed statistically significant intergroup differences (SSID) for VAS (SMD = -0.55; 95% CI = -0.82 to -0.27; Z = 3.90 (p < 0.001)), PPT (SMD = -0.45; 95% CI = -0.89 to 0.00; Z = 1.97 (p = 0.05)) and MMO (SMD = -0.45; 95% CI = -0.89 to 0.00; Z = 1.97 (p = 0.05)), favouring PBMT compared to control treatment strategies. Sensitivity analysis revealed SSID (SMD = -0.53; 95% CI = -0.73 to -0.32; Z = 5.02 (p < 0.0001)) with low heterogeneity (Τ² = 0.02; χ² = 16.03 (p = 0.31); I² = 13%). Hence, this review, for first time, proposed suggested recommendations for PBMT protocols and methodology for future extensive TMD research.

Chronic Pain Causes Peripheral and Central Responses in MIA-Induced TMJOA Rats

Chronic pain is the predominant symptom that drives temporomandibular joint osteoarthritis (TMJOA) patients to seek medical care; however, currently used treatment modalities remain less effective. This study aimed to investigate chronic pain and the peripheral and central responses in monoiodoacetate (MIA)-induced TMJOA rats. First, the appropriate dose of MIA was determined based on pain behavior assessment in rats. Alterations of the condylar structure in TMJOA rats were evaluated by histological staining and micro-computed tomography (micro-CT). Second, the period of TMJOA chronic pain was further explored by assessing the numbers of glial fibrillary acidic protein (GFAP)-positive astrocytes and ionized calcium-binding adaptor molecule 1 (IBA-1)-positive microglia in the trigeminal spinal nucleus (TSN) and performing nonsteroidal anti-inflammatory drug (NSAID) efficacy experiments. Finally, the expression of neurofilament 200 (NF200), calcitonin gene-related peptide (CGRP), and isolectin B4 (IB4) in the trigeminal ganglion (TG) and TSN was assessed by immunofluorescence. MIA at 4 mg/kg was considered an appropriate dose. Gradual MIA-induced alterations of the condylar structure were correlated with temporomandibular joint (TMJ) pain. The numbers of GFAP- and IBA-1-positive cells were increased at 2, 3, and 4 weeks after MIA injection. NSAIDs failed to alleviate pain behavior 10 days after MIA injection. CGRP and IB4 levels in the TG and TSN were upregulated at 2 and 4 weeks. These results suggest that TMJOA-related chronic pain emerged 2 weeks after MIA injection. CGRP- and IB4-positive afferents in both the peripheral and central nervous systems may be involved in MIA-induced TMJOA-related chronic pain in rats.

Healthcare utilisation and costs for temporomandibular disorders: a descriptive, cross-sectional study

OBJECTIVE

Temporomandibular joint disorder (TMD) requires long-term management and can be a financial burden for patients. Here, we investigated the treatment received by people diagnosed with TMD and its relevant costs.

DESIGN

A descriptive, cross-sectional study.

SETTING AND PARTICIPANTS

We performed secondary data analysis of health insurance claims data provided by the Health Insurance Assessment and Review (HIRA) of the Republic of Korea. We reviewed the records of 10 041 patients who were diagnosed with TMD and who utilised outpatient healthcare service at least once between January and December 2017.

PRIMARY AND SECONDARY OUTCOME MEASURES

Data on use of medical services, hospitalisations, sociodemographic factors, treatment and medication were retrieved and analysed. Cost was defined as the cost of care incurred by a health insurance beneficiary at a care facility.

RESULTS

We reported the characteristics as medians, frequencies and percentages and found that most TMD patients were outpatients, women (58.9%) and in their 20s (46.4%). For visit type, 85.9% of all patients had an outpatient dental medical visit, with most visiting dental clinics and dental hospitals. Western medicine (WM; 9.8%) was prescribed more often, followed by Korean medicine (KM; 8.2%). The median expense per patient was highest among those in their 20s (58.00, 23.90, 53.40, 65.90 US$ for overall, WM, dental medicine (DM) and KM, respectively). Consultation fees accounted for the greatest percentage (42.8%) of DM and WM care expenses, while injection/non-surgical intervention fees accounted for the greatest percentage of KM care expenses. The most commonly used treatments for TMD were temporomandibular joint stimulation therapy (51.1%) and acupuncture (19.9%), considered as the most basic care for TMD. Psychosomatic agents (86.4%) were the most commonly used medications in outpatients.

CONCLUSIONS

While people with TMD most commonly received temporomandibular stimulation therapy, the costs and duration of treatment varied significantly for these patients.

COMT Genotype and Efficacy of Propranolol for TMD Pain: A Randomized Trial

Propranolol is a nonselective β-adrenergic receptor antagonist that is efficacious in reducing facial pain. There is evidence that its analgesic efficacy might be modified by variants of the catechol-O-methyltransferase (COMT) gene. We tested the hypothesis in a subset of 143 non-Hispanic Whites from a randomized controlled trial of patients with painful temporomandibular disorder (TMD). Patients were genotyped for rs4680, a single nucleotide polymorphism of COMT, and randomly allocated to either propranolol 60 mg twice daily or placebo. During the 9-wk follow-up period, patients recorded daily ratings of facial pain intensity and duration; the product was computed as an index of facial pain. Postbaseline change in the index at week 9 (the primary endpoint) was analyzed as a continuous variable and dichotomized at thresholds of ≥30% and ≥50% reduction. Mixed models for repeated measures tested for the genotype × treatment group interaction and estimated means, odds ratios (ORs), and 95% confidence limits (95% CLs) of efficacy within COMT genotypes assuming an additive genetic model. In secondary analysis, the cumulative response curves were plotted for dichotomized reductions ranging from ≥20% to ≥70%, and genotype differences in area under the curve percentages (%AUC) were calculated to signify efficacy. Mean index reduction did not differ significantly (P = 0.277) according to genotype, whereas the dichotomized ≥30% reduction revealed greater efficacy among G:G homozygotes (OR = 10.9, 95%CL = 2.4, 50.7) than among A:A homozygotes (OR = 0.8, 95%CL = 0.2, 3.2) with statistically significant interaction (P = 0.035). Cumulative response curves confirmed greater (P = 0.003) efficacy for G:G homozygotes (%AUC difference = 43.7, 95%CL = 15.4, 72.1) than for A:A homozygotes (%AUC difference = 6.5, 95%CL = -30.2, 43.2). The observed antagonistic effect of the A allele on propranolol’s efficacy was opposite the synergistic effect hypothesized a priori. This unexpected result highlights the need for better knowledge of COMT’s role in pain pathogenesis if the gene is to be used for precision-medicine treatment of TMD (ClinicalTrials.gov NCT02437383).

Temporomandibular joint imaging: current clinical applications, biochemical comparison with the intervertebral disc and knee meniscus, and opportunities for advancement

Temporomandibular disorders encompass multiple pathologies of the temporomandibular joint that manifest as middle/inner ear symptoms, headache, and/or localized TMJ symptoms. There is an important although somewhat limited role of imaging in the diagnostic evaluation of temporomandibular disorders. In this manuscript, we provide a comprehensive review of TMJ anatomy, outline potentially important features of TMJ disc ultrastructure and biochemistry in comparison with the intervertebral disc and knee meniscus, and provide imaging examples of the TMJ abnormalities currently evaluable with MRI and CT. In addition, we provide an overview of emerging and investigational TMJ imaging techniques in order to encourage further imaging research based on the biomechanical alterations of the TMJ disc.

The effect of natural products in animal models of temporomandibular disorders

Treatment of temporomandibular disorders (TMD) is a challenge for health care professionals. Therefore, new approaches have been investigated, such as the use of natural products.

Efficacy, safety, and economic assessment of hominis placental pharmacopuncture for chronic temporomandibular disorder: a protocol for a multicentre randomised controlled trial

BACKGROUND

Temporomandibular disorder (TMD) is a condition encompassing clinical symptoms of the temporomandibular joint, masseter muscle, and surrounding structures. Hominis placental pharmacopuncture (HPP), consisting of human placental extract, has been reported as effective for treating chronic musculoskeletal disorders, but a lack of well-designed randomised controlled trial s (RCTs) mean there is insufficient evidence to prove the efficacy of HPP.

METHODS

This study is a two-arm parallel, assessor-blinded, multi-centre, randomised controlled trial. We will enrol 82 chronic TMD patients from rwo Korean Medicine hospitals in Axis 1, Group I according to RDC/TMD diagnostic criteria, and randomly allocate 41 patients each to an HPP group and a physical therapy (PT) group. Treatment will be administered in 10 rounds, after which there will be four follow-up visits 6, 9, 13, and 25 weeks from baseline. The primary end point is 6 weeks after baseline, and the primary outcome is the difference in Visual Analogue Scale (VAS) score for temporomandibular pain between baseline and week 6. Secondary outcomes will be Numeric Rating Scale (NRS) scores for temporomandibular pain and discomfort, temporomandibular joint range of motion, the Korean version of Beck's Depression Index-II (K-BDI-II), Jaw Functional Limitation Scale (JFLS), Patient Global Impression of Change (PGIC) scores, and quality of life. Using data on adverse events and cost-effectiveness in the two groups, we will perform a safety assessment and a cost-effectiveness analysis (economic assessment).

DISCUSSION

This study will assess the efficacy and safety of HPP for chronic TMD compared with PT. This RCT will provide evidence for the efficacy, safety, and economics of HPP.

TRIAL REGISTRATION

clinicaTrials.gov (NCT04087005) / Clinical Research Information Service (CRIS) (KCT0004437) / IRB (JASENG 2017-09-002-002, KHNMCOH 2019-08-002) / Ministry of Food and Drug Safety (No. 31886).

Facial Pain: A Comprehensive Review and Proposal for a Pragmatic Diagnostic Approach

BACKGROUND

Facial pain, alone or combined with other symptoms, is a frequent complaint. Moreover, it is a symptom situated at, more than any other pain condition, a crosspoint where several disciplines meet, for example, dentists; manual therapists; ophthalmologists; psychologists; and ear-nose-throat, pain, and internal medicine physicians besides neurologists and neurosurgeons. Recently, a new version of the most widely used classification system among neurologists for headache and facial pain, the International Classification of Headache Disorders, has been published.

OBJECTIVE

The aims of this study were to provide an overview of the most prevalent etiologies of facial pain and to provide a generic framework for the neurologist on how to manage patients presenting with facial pain.

METHODS

An overview of the different etiologies of facial pain is provided from the viewpoint of the respective clinical specialties that are confronted with facial pain. Key message: Caregivers should "think outside their own box" and refer to other disciplines when indicated. If not, a correct diagnosis can be delayed and unnecessary treatments might be given. The presented framework is aimed at excluding life- or organ-threatening diseases, providing several clinical clues and indications for technical investigations, and ultimately leading to the correct diagnosis and/or referral to other disciplines.

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.

Microneedles Coated with Tramadol Exhibit Antinociceptive Effect in a Rat Model of Temporomandibular Hypernociception

Coated microneedles have emerged as a promising drug delivery system for inflammatory pain treatment. We have previously shown that tramadol injection into the rat temporomandibular joint (TMJ) induces an antinociceptive and anti-inflammatory effect. In this study, microneedles coated with tramadol were investigated as a platform to treat TMJ pain. Male Wistar rats were administered tramadol using an intra-TMJ injection or with microneedles coated with tramadol, followed by 1.5% formalin nociceptive challenge administered 15 minutes later. The nociceptive behavior of rats was evaluated, and their periarticular tissues were removed after euthanasia for analysis. The duration of antinociceptive effect was determined by performing the formalin challenge at different time points extending up to 6 days post tramadol administration. Microneedles coated with tramadol produced an antinociceptive effect similar to injection of tramadol into the rat TMJ. Surprisingly, tramadol delivery using coated microneedles produced a more durable antinociceptive effect lasting as much as 2 days post tramadol delivery as compared with an antinociceptive effect lasting under 2 hours from intra-TMJ injection of tramadol. The proinflammatory cytokines tumor necrosis factor-α and interleukin-1β (IL-1β) were found to be reduced, whereas the anti-inflammatory cytokine IL-10 was found to be elevated in tramadol-treated groups. In conclusion, microneedles coated with tramadol can offer a therapeutic option for pain control of inflammatory disorders in the TMJ.

Pain Complaints in Patients Undergoing Orthognathic Surgery

The aim of this retrospective study was to assess the frequency of orofacial (nonodontogenic, neuropathic, or atypical) and temporomandibular joint (TMJ) and/or masticatory muscle pain in orthognathic patients in a tertiary institution. A total of 286 consecutive patients undergoing sagittal split osteotomy from 2014 to 2016 were included. Thirty-nine (13.6%) patients presented with TMJ pain and 10 (3.5%) with orofacial nonodontogenic pain before orthognathic surgery; 79.6% (39/49) of these patients had no pain 1 year after surgery. Twenty-nine patients (12.2%) with no preoperative orofacial pain and 22 (9.3%) without preoperative TMJ pain presented with pain 1 year after surgery. Fifty-one (17.8%) of the 286 patients treated for orthognathic cases at our center over the 3-year period presented with pain 1 year after surgery. Most patients were managed conservatively with nonsurgical therapeutic modalities including counseling, physical therapy, warmth application, and bilateral chewing and splint therapy. In patients with TMJ pain refractory to conservative treatment, arthroscopic surgery was advised and successful in all patients for both pain reduction and improvement of the maximal interincisal opening. TMJ symptoms do develop after orthognathic surgery in patients with and without a previous history of TMJ complaints. Most patients can be managed with nonsurgical therapeutic modalities.

Intra-articular biomaterials-assisted delivery to treat temporomandibular joint disorders

The temporomandibular joint disorder, also known as myofascial pain syndrome, is considered one of the prevalent chronic pain diseases caused by muscle inflammation and cartilage degradation in head and neck, and thus influences even biopsychosocial conditions in a lifetime. There are several current treatment methodologies relieving inflammation and preventing degradation of the joint complex. One of the promising non-surgical treatment methods is an intra-articular injection of drugs such as corticosteroids, analgesics, and anti-depressants. However, the side effects of drugs due to frequent injections and over-doses, including dizziness, dry mouth, and possible drug dependency are considered limitations. Thus, the delivery of therapeutic molecules through the use of nano/microparticles is currently considered as a promising strategy primarily due to the controlled release. This review highlights the nano/microparticle systems for effective intra-articular therapeutics delivery to prevent cartilage degradation and protect subchondral bone in a temporomandibular joint.

Management of pain in patients with temporomandibular disorder (TMD): challenges and solutions

Thanks to advances in neuroscience, biopsychosocial models for diagnostics and treatment (including physical, psychological, and pharmacological therapies) currently have more clinical support and scientific growth. At present, a conservative treatment approach prevails over surgery, given it is less aggressive and usually results in satisfactory clinical outcomes in mild–moderate temporomandibular disorder (TMD). The aim of this review is to evaluate the recent evidence, identify challenges, and propose solutions from a clinical point of view for patients with craniofacial pain and TMD. The treatment we propose is structured in a multi-modal approach based on a biobehavioral approach that includes medical, physiotherapeutic, psychological, and dental treatments. We also propose a new biobehavioral model regarding pain perception and motor behavior for the diagnosis and treatment of patients with painful TMD.

Temporomandibular Joint Regenerative Medicine

The temporomandibular joint (TMJ) is an articulation formed between the temporal bone and the mandibular condyle which is commonly affected. These affections are often so painful during fundamental oral activities that patients have lower quality of life. Limitations of therapeutics for severe TMJ diseases have led to increased interest in regenerative strategies combining stem cells, implantable scaffolds and well-targeting bioactive molecules. To succeed in functional and structural regeneration of TMJ is very challenging. Innovative strategies and biomaterials are absolutely crucial because TMJ can be considered as one of the most difficult tissues to regenerate due to its limited healing capacity, its unique histological and structural properties and the necessity for long-term prevention of its ossified or fibrous adhesions. The ideal approach for TMJ regeneration is a unique scaffold functionalized with an osteochondral molecular gradient containing a single stem cell population able to undergo osteogenic and chondrogenic differentiation such as BMSCs, ADSCs or DPSCs. The key for this complex regeneration is the functionalization with active molecules such as IGF-1, TGF-β1 or bFGF. This regeneration can be optimized by nano/micro-assisted functionalization and by spatiotemporal drug delivery systems orchestrating the 3D formation of TMJ tissues.

High-dose opioids for chronic non-cancer pain: an overview of Cochrane Reviews

BACKGROUND

Chronic pain is typically described as pain on most days for at least three months. Chronic non-cancer pain (CNCP) is any chronic pain that is not due to a malignancy. Chronic non-cancer pain in adults is a common and complex clinical issue where opioids are routinely used for pain management. There are concerns that the use of high doses of opioids for chronic non-cancer pain lacks evidence of effectiveness and may increase the risk of adverse events.

OBJECTIVES

To describe the evidence from Cochrane Reviews and Overviews regarding the efficacy and safety of high-dose opioids (here defined as 200 mg morphine equivalent or more per day) for chronic non-cancer pain.

METHODS

We identified Cochrane Reviews and Overviews through a search of the Cochrane Database of Systematic Reviews (The Cochrane Library). The date of the last search was 18 April 2017. Two review authors independently assessed the search results. We planned to analyse data on any opioid agent used at high dose for two weeks or more for the treatment of chronic non-cancer pain in adults.

MAIN RESULTS

We did not identify any reviews or overviews meeting the inclusion criteria. The excluded reviews largely reflected low doses or titrated doses where all doses were analysed as a single group; no data for high dose only could be extracted.

AUTHORS' CONCLUSIONS

There is a critical lack of high-quality evidence regarding how well high-dose opioids work for the management of chronic non-cancer pain in adults, and regarding the presence and severity of adverse events. No evidence-based argument can be made on the use of high-dose opioids, i.e. 200 mg morphine equivalent or more daily, in clinical practice. Trials typically used doses below our cut-off; we need to know the efficacy and harm of higher doses, which are often used in clinical practice.

Adverse events associated with medium- and long-term use of opioids for chronic non-cancer pain: an overview of Cochrane Reviews

BACKGROUND

Chronic pain is common and can be challenging to manage. Despite increased utilisation of opioids, the safety and efficacy of long-term use of these compounds for chronic non-cancer pain (CNCP) remains controversial. This overview of Cochrane Reviews complements the overview entitled 'High-dose opioids for chronic non-cancer pain: an overview of Cochrane Reviews'.

OBJECTIVES

To provide an overview of the occurrence and nature of adverse events associated with any opioid agent (any dose, frequency, or route of administration) used on a medium- or long-term basis for the treatment of CNCP in adults.

METHODS

We searched the Cochrane Database of Systematic Reviews (the Cochrane Library) Issue 3, 2017 on 8 March 2017 to identify all Cochrane Reviews of studies of medium- or long-term opioid use (2 weeks or more) for CNCP in adults aged 18 and over. We assessed the quality of the reviews using the AMSTAR criteria (Assessing the Methodological Quality of Systematic Reviews) as adapted for Cochrane Overviews. We assessed the quality of the evidence for the outcomes using the GRADE framework.

MAIN RESULTS

We included a total of 16 reviews in our overview, of which 14 presented unique quantitative data. These 14 Cochrane Reviews investigated 14 different opioid agents that were administered for time periods of two weeks or longer. The longest study was 13 months in duration, with most in the 6- to 16-week range. The quality of the included reviews was high using AMSTAR criteria, with 11 reviews meeting all 10 criteria, and 5 of the reviews meeting 9 out of 10, not scoring a point for either duplicate study selection and data extraction, or searching for articles irrespective of language and publication type. The quality of the evidence for the generic adverse event outcomes according to GRADE ranged from very low to moderate, with risk of bias and imprecision being identified for the following generic adverse event outcomes: any adverse event, any serious adverse event, and withdrawals due to adverse events. A GRADE assessment of the quality of the evidence for specific adverse events led to a downgrading to very low- to moderate-quality evidence due to risk of bias, indirectness, and imprecision.We calculated the equivalent milligrams of morphine per 24 hours for each opioid studied (buprenorphine, codeine, dextropropoxyphene, dihydrocodeine, fentanyl, hydromorphone, levorphanol, methadone, morphine, oxycodone, oxymorphone, tapentadol, tilidine, and tramadol). In the 14 Cochrane Reviews providing unique quantitative data, there were 61 studies with a total of 18,679 randomised participants; 12 of these studies had a cross-over design with two to four arms and a total of 796 participants. Based on the 14 selected Cochrane Reviews, there was a significantly increased risk of experiencing any adverse event with opioids compared to placebo (risk ratio (RR) 1.42, 95% confidence interval (CI) 1.22 to 1.66) as well as with opioids compared to a non-opioid active pharmacological comparator, with a similar risk ratio (RR 1.21, 95% CI 1.10 to 1.33). There was also a significantly increased risk of experiencing a serious adverse event with opioids compared to placebo (RR 2.75, 95% CI 2.06 to 3.67). Furthermore, we found significantly increased risk ratios with opioids compared to placebo for a number of specific adverse events: constipation, dizziness, drowsiness, fatigue, hot flushes, increased sweating, nausea, pruritus, and vomiting.There was no data on any of the following prespecified adverse events of interest in any of the included reviews in this overview of Cochrane Reviews: addiction, cognitive dysfunction, depressive symptoms or mood disturbances, hypogonadism or other endocrine dysfunction, respiratory depression, sexual dysfunction, and sleep apnoea or sleep-disordered breathing. We found no data for adverse events analysed by sex or ethnicity.

AUTHORS' CONCLUSIONS

A number of adverse events, including serious adverse events, are associated with the medium- and long-term use of opioids for CNCP. The absolute event rate for any adverse event with opioids in trials using a placebo as comparison was 78%, with an absolute event rate of 7.5% for any serious adverse event. Based on the adverse events identified, clinically relevant benefit would need to be clearly demonstrated before long-term use could be considered in people with CNCP in clinical practice. A number of adverse events that we would have expected to occur with opioid use were not reported in the included Cochrane Reviews. Going forward, we recommend more rigorous identification and reporting of all adverse events in randomised controlled trials and systematic reviews on opioid therapy. The absence of data for many adverse events represents a serious limitation of the evidence on opioids. We also recommend extending study follow-up, as a latency of onset may exist for some adverse events.

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.

Central Sensitization-Based Classification for Temporomandibular Disorders: A Pathogenetic Hypothesis

Dysregulation of Autonomic Nervous System (ANS) and central pain pathways in temporomandibular disorders (TMD) is a growing evidence. Authors include some forms of TMD among central sensitization syndromes (CSS), a group of pathologies characterized by central morphofunctional alterations. Central Sensitization Inventory (CSI) is useful for clinical diagnosis. Clinical examination and CSI cannot identify the central site(s) affected in these diseases. Ultralow frequency transcutaneous electrical nerve stimulation (ULFTENS) is extensively used in TMD and in dental clinical practice, because of its effects on descending pain modulation pathways. The Diagnostic Criteria for TMD (DC/TMD) are the most accurate tool for diagnosis and classification of TMD. However, it includes CSI to investigate central aspects of TMD. Preliminary data on sensory ULFTENS show it is a reliable tool for the study of central and autonomic pathways in TMD. An alternative classification based on the presence of Central Sensitization and on individual response to sensory ULFTENS is proposed. TMD may be classified into 4 groups: (a) TMD with Central Sensitization ULFTENS Responders; (b) TMD with Central Sensitization ULFTENS Nonresponders; (c) TMD without Central Sensitization ULFTENS Responders; (d) TMD without Central Sensitization ULFTENS Nonresponders. This pathogenic classification of TMD may help to differentiate therapy and aetiology.

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.

Tumor necrosis factor-Alpha stimulates cytokine expression and transient sensitization of trigeminal nociceptive neurons

OBJECTIVE

Elevated levels of tumor necrosis factor- alpha (TNF-α) in the capsule of the temporomandibular joint (TMJ) are implicated in the underlying pathology of temporomandibular disorders (TMD). TMD are a group of conditions that result in pain in the TMJ and/or muscles of mastication, and are associated with significant social and economic burdens. The goal of this study was to investigate the effect of elevated TNF-α levels in the TMJ capsule on nocifensive behavioral response to mechanical stimulation of trigeminal neurons and regulation of cytokines within the trigeminal ganglion.

DESIGN

Male Sprague-Dawley rats were injected bilaterally in the TMJ capsule with TNF-α and changes in nocifensive head withdrawal responses to mechanical stimulation of cutaneous tissue directly over the capsule was determined using von Frey filaments. Cytokine levels in trigeminal ganglia were determined by protein array analysis at several time points post injection and correlated to nocifensive behavior.

RESULTS

TNF-α caused a significant increase in the average number of nocifensive responses when compared to naive and vehicle treated animals 2h post injection, but levels returned to control levels at 24h. Based on array analysis, the levels of eight cytokines were significantly elevated above vehicle control levels at 2h following TNF-α injection, but all eight had returned to the vehicle control levels after 24h.

CONCLUSIONS

Our findings provide evidence that elevated levels of TNF-α in the joint capsule, which is reported to occur in TMD, promotes nociception in trigeminal ganglia neurons via a mechanism that temporally correlates with differential regulation of several cytokines.

Stem Cells for Temporomandibular Joint Repair and Regeneration

Temporomandibular Disorders (TMD) represent a heterogeneous group of musculoskeletal and neuromuscular conditions involving the temporomandibular joint (TMJ), masticatory muscles and/or associated structures. They are a major cause of non-dental orofacial pain. As a group, they are often multi-factorial in nature and have no common etiology or biological explanations. TMD can be broadly divided into masticatory muscle and TMJ disorders. TMJ disorders are characterized by intra-articular positional and/or structural abnormalities. The most common type of TMJ disorders involves displacement of the TMJ articular disc that precedes progressive degenerative changes of the joint leading to osteoarthritis (OA). In the past decade, progress made in the development of stem cell-based therapies and tissue engineering have provided alternative methods to attenuate the disease symptoms and even replace the diseased tissue in the treatment of TMJ disorders. Resident mesenchymal stem cells (MSCs) have been isolated from the synovia of TMJ, suggesting an important role in the repair and regeneration of TMJ. The seminal discovery of pluripotent stem cells including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have provided promising cell sources for drug discovery, transplantation as well as for tissue engineering of TMJ condylar cartilage and disc. This review discusses the most recent advances in development of stem cell-based treatments for TMJ disorders through innovative approaches of cell-based therapeutics, tissue engineering and drug discovery.

Recent Advancements in Temporomandibular Disorders (TMDs)

TMDs are a group of conditions affecting the joint and or the muscles of mastication.TMDs consist of three main groups of conditions: myofascial pain; disc disorders; TMJ arthritides.The gold standard diagnostic criteria for research involving TMDs are the Research Diagnostic Criteria for TMDs (RDC/TMD). A pragmatic clinically applicable alternative is the Clinical examination protocol for TMDs (CEP-TMD).Signs and symptoms can include: pain in masticatory musculature and or the joint; noises associated with joint movements; locking; headache; otalgia.TMDs' aetiology is multifactorial and biopsychosocial in nature.Reversible conservative management as defined by the American Association of Dental Research is the initial management of choice for all subgroups of TMDs.

Temporomandibular disorders: evaluation and management

Temporomandibular disorders remain a common cause of visits to primary care physicians, internists, pediatricians, and emergency departments. Advances in the clinical diagnosis, radiographic imaging, and classification of these disorders have improved long-term management. There are several types of disorders of the masticatory muscles and the temporomandibular joint as well as associated structures and each may have a complex cause, clinical course, and response to therapy. Host susceptibility plays a role at several stages of these disorders. Future research offers greater possibility in defining this heterogeneous group of disorders and providing more focused and effective treatment strategies.

Evaluation of Glucosamine sulfate and Ibuprofen effects in patients with temporomandibular joint osteoarthritis symptom

OBJECTIVE

Ibuprofen - a non-steroidal anti-inflammatory drug (NSAID)- and glucosamine sulfate - a natural compound and a food supplement- are two therapeutic agents which have been widely used for treatment of patients with temporomandibular joint (TMJ) disorders. This study was aimed to compare the effectiveness and safety of these two medications in the treatment of patients suffering from TMJ disorders.

METHODS

After obtaining informed consent, 60 patients were randomly allocated to two groups. Patients with painful TMJ, TMJ crepitation or limitation of mouth opening entered the study. Exclusion criteria were history of depressive disorders, cardiovascular disease, musculoskeletal disorders, asthma, gastrointestinal problems, kidney or liver dysfunction or diabetes mellitus, dental diseases needing ongoing treatment; taking aspirin or warfarin, or concomitant treatment of TMJ disorder with other agents or methods. Thirty patients were treated with ibuprofen 400 mg twice a day, (mean age 27.12 ± 10.83 years) and 30 patients (mean age 26.60 ± 10) were treated with glucosamine sulfate 1500 mg daily. Patients were visited 30, 60 and 90 days after starting the treatment, pain and mandibular opening were checked and compared within and between two groups.

FINDINGS

Comparing with baseline measures, both groups had significantly improved post-treatment pain (P < 0.0001 for both groups) and mandibular opening (P value: 0.001 for glucosamine sulfate and 0.03 for ibuprofen). Post treatment pain and mandibular opening showed significantly more improvement in the glucosamine treated patients (P < 0.0001 and 0.01 respectively). Rate of adverse events was significantly lower in the P value glucosamine sulfate group (P < 0.0001).

CONCLUSION

This investigation demonstrated that comparing with a commonly prescribed NSAID - ibuprofen-, glucosamine sulfate is a more effective and safer therapeutic agent for treatment of patients with TMJ degenerative join disorder.

Orofacial pain: a guide for the headache physician

Orofacial pain represents a significant burden in terms of morbidity and health service utilization. It includes very common disorders such as toothache and temporomandibular disorders, as well as rare orofacial pain syndromes. Many orofacial pain conditions have overlapping presentations, and diagnostic uncertainty is frequently encountered in clinical practice. This review provides a clinically orientated overview of common and uncommon orofacial pain presentations and diagnoses, with an emphasis on conditions that may be unfamiliar to the headache physician. A holistic approach to orofacial pain management is important, and the social, cultural, psychological and cognitive context of each patient needs to be considered in the process of diagnostic formulation, as well as in the development of a pain management plan according to the biopsychosocial model. Recognition of psychological comorbidities will assist in diagnosis and management planning.

Epidemiology, diagnosis, and treatment of temporomandibular disorders

Temporomandibular disorder (TMD) is a multifactorial disease process caused by muscle hyperfunction or parafunction, traumatic injuries, hormonal influences, and articular changes. Symptoms of TMD include decreased mandibular range of motion, muscle and joint pain, joint crepitus, and functional limitation or deviation of jaw opening. Only after failure of noninvasive options should more invasive and nonreversible treatments be initiated. Treatment can be divided into noninvasive, minimally invasive, and invasive options. Temporomandibular joint replacement is reserved for severely damaged joints with end-stage disease that has failed all other more conservative treatment modalities.

Clinical pharmacology of analgesics assessed with human experimental pain models: bridging basic and clinical research

The medical impact of pain is such that much effort is being applied to develop novel analgesic drugs directed towards new targets and to investigate the analgesic efficacy of known drugs. Ongoing research requires cost-saving tools to translate basic science knowledge into clinically effective analgesic compounds. In this review we have re-examined the prediction of clinical analgesia by human experimental pain models as a basis for model selection in phase I studies. The overall prediction of analgesic efficacy or failure of a drug correlated well between experimental and clinical settings. However, correct model selection requires more detailed information about which model predicts a particular clinical pain condition. We hypothesized that if an analgesic drug was effective in an experimental pain model and also a specific clinical pain condition, then that model might be predictive for that particular condition and should be selected for development as an analgesic for that condition. The validity of the prediction increases with an increase in the numbers of analgesic drug classes for which this agreement was shown. From available evidence, only five clinical pain conditions were correctly predicted by seven different pain models for at least three different drugs. Most of these models combine a sensitization method. The analysis also identified several models with low impact with respect to their clinical translation. Thus, the presently identified agreements and non-agreements between analgesic effects on experimental and on clinical pain may serve as a solid basis to identify complex sets of human pain models that bridge basic science with clinical pain research.

[Clinical management of masticatory muscle pain: an update of the recommendations]

Besides the different forms of odontalgia, myalgias of the masticatory muscles are the most frequent noninfectious complaints in the orofacial region. After summarizing the recommendations set forth by the Interdisciplinary Working Group of Orofacial Pain within the German Chapter of the IASP (German Pain Society), we present the current state of knowledge regarding the etiology, diagnosis, and therapeutic options, based on an extensive literature search. A systematic literature search was carried out in PubMed, the Cochrane Library, and the database of the Deutsche Zahnärztliche Zeitschrift. The results corroborate our previous recommendations that for the majority of patients pain reduction or pain relief can be achieved with noninvasive, reversible methods. Short- and long-term trials have added more evidence to the fact that different therapeutic measures have similar efficacy. In patients with chronic myalgias of the jaw muscles, involvement of a psychotherapist is crucial. Patient education, oral appliances, physiotherapeutic exercises, and acupuncture are recommended therapeutic measures, while physical therapy, pharmacotherapy, and psychological therapy received a limited recommendation.

Multi-dimensionality of chronic pain of the oral cavity and face

Orofacial pain in its broadest definition can affect up to 7% of the population. Its diagnosis and initial management falls between dentists and doctors and in the secondary care sector among pain physicians, headache neurologists and oral physicians. Chronic facial pain is a long term condition and like all other chronic pain is associated with numerous co-morbidities and treatment outcomes are often related to the presenting co-morbidities such as depression, anxiety, catastrophising and presence of other chronic pain which must be addressed as part of management . The majority of orofacial pain is continuous so a history of episodic pain narrows down the differentials. There are specific oral conditions that rarely present extra orally such as atypical odontalgia and burning mouth syndrome whereas others will present in both areas. Musculoskeletal pain related to the muscles of mastication is very common and may also be associated with disc problems. Trigeminal neuralgia and the rarer glossopharyngeal neuralgia are specific diagnosis with defined care pathways. Other trigeminal neuropathic pain which can be associated with neuropathy is caused most frequently by trauma but secondary causes such as malignancy, infection and auto-immune causes need to be considered. Management is along the lines of other neuropathic pain using accepted pharmacotherapy with psychological support. If no other diagnostic criteria are fulfilled than a diagnosis of chronic or persistent idiopathic facial pain is made and often a combination of antidepressants and cognitive behaviour therapy is effective. Facial pain patients should be managed by a multidisciplinary team.

Adjacent, distal, or combination of point-selective effects of acupuncture on temporomandibular joint disorders: A randomized, single-blind, assessor-blind controlled trial

Background

The objectives of this study were to compare the efficacy of acupuncture among different types and to evaluate point-selective pain relief effects between selected adjacent or distant points in participants with temporomandibular joint disorders (TMDs).

Methods

Forty-two participants were randomly allocated to three groups: an adjacent point selection group (Trt, n = 14), a distant point selection group (Con1, n = 14), or a combination group (Con2, n = 14). All three groups received a total of six acupuncture sessions (twice a week for 3 weeks), the outcomes being assessed pain intensity using a 10-cm visual analogue scale, and the palpation index of the muscle and temporomandibular joint every week of treatment and 4 weeks after the end of treatment.

Results

The pain intensity was reduced in the Trt (34%), Con1 (31%), and Con2 (36%) groups after 3 weeks compared with each group's baseline, with no significant difference among the three groups (p = 0.5867). Similarly, the palpation index was decreased by 52% (Trt), 62% (Con1), and 50% (Con2) after 3 weeks of treatment, but no significant differences between groups were shown (p = 0.3289).

Conclusion

Our results suggest that point-selective effects among adjacent, distal, or a combination of acupoints are hardly associated with pain intensity or palpation index in participants with TMDs. Larger sample size trials are required to overcome the shortcomings of the study.

Dysregulation of the autonomous nervous system in patients with temporomandibular disorder: a pupillometric study

The role of the autonomic nervous system (ANS) was recently investigated in Temporomandibular disorders (TMD). Several authors argue that in subjects with TMD there is a dysregulation of ANS. Recent literature support that Pupillometry is a simple non-invasive tool to study ANS. The aim of this study was to investigate the relationship between TMD and ANS activity using pupillometry recording in Infrared light at rest Mandible Position (RP); Infrared light at Forced Habitual Occlusion (FHO); Yellow-green light at RP; Yellow-green light at FHO. Forty female subjects were enrolled: 20 case patients showed TMD based on the Research Diagnostic Criteria for TMD, and 20 control patients, aged matched, had no signs or symptoms of TMD. Statistical analysis was performed on average pupil size. Ratio between pupil size in FHO and RP (FHO/RP ratio) and yellow-green and infrared (light/darkness ratio) lighting were carried out. Within group differences of pupil size and of “ratio” were analyzed using a paired t test, while differences of pupil size between groups were tested using an unpaired t test. Statistical comparisons between groups showed no significant differences of absolute values of pupil dimension in RP and FHO, both in yellow-green and in infrared lighting. In addition, there were no significant differences within groups comparing RP and FHO in yellow-green light. In within group comparison of pupil size, differences between RP and FHO were significant in infrared conditions. Control subjects increased, whereas TMD patients decreased pupil size at FHO in infrared lightening. FHO/RP ratio in darkness and light/darkness ratio in RP were significantly different between groups. Taken together, these data suggest that TMD subjects have an impairment of the sympathetic-adrenergic component of the ANS to be activated under stress. The present study provides preliminary pupillometric data confirming that adrenergic function is dysregulated in patients with TMD.

Behavioral testing in rodent models of orofacial neuropathic and inflammatory pain

Orofacial pain conditions are often very debilitating to the patient and difficult to treat. While clinical interest is high, the proportion of studies performed in the orofacial region in laboratory animals is relatively low, compared with other body regions. This is partly due to difficulties in testing freely moving animals and therefore lack of reliable testing methods. Here we present a comprehensive review of the currently used rodent models of inflammatory and neuropathic pain adapted to the orofacial areas, taking into account the difficulties and drawbacks of the existing approaches. We examine the available testing methods and procedures used for assessing the behavioral responses in the face in both mice and rats and provide a summary of some pharmacological agents used in these paradigms to date. The use of these agents in animal models is also compared with outcomes observed in the clinic.