Bruxism and oro-facial pain not related to temporomandibular disorder conditions: Comorbidities or risk factors?

INTRODUCTION: Bruxism has historically been of particular interest to the field of dentistry, primarily due to the inferred damage it may cause to the dentition and supporting periodontal structures. The definition of bruxism itself has undergone multiple changes over time. In addition, the effects of bruxism as it relates to oro-facial pain conditions has remained a debatable topic. PURPOSE: To review the available literature relating to bruxism and non-temporomandibular disorder (TMD) pain conditions. METHODS: A literature search was conducted with the assistance of an expert librarian. The following databases were reviewed: PubMed, MEDLINE, EMBASE and Google Scholar. For additional references, articles were also retrieved by hand search from the selected papers. Any articles that were not published in English, or the focus were related to temporomandibular disorders were excluded. CONCLUSIONS: While bruxism and certain headache conditions do tend to occur together frequently, evidence relating to any clear common pathophysiological mechanism has yet to be fully elucidated. Robust evidence as it relates to the relationship between bruxism and other non-TMD oro-facial pains is also lacking.

Biomechanics and Derangements of the Temporomandibular Joint.

The human temporomandibular joint, is a ginglymo-arthrodial joint. The articular disk serves as a fibrous, viscoelastic structure that allows force distribution and smooth movement of the joint in its normal arrangement during mandibular movements. Most studies suggest that in the normal disk position the posterior band is located at the 12'o clock position within the glenoid fossa in the closed mouth posture. When the biomechanics of the joint is altered, the disk may be displaced creating an abnormal relationship between the disk, condyle, and the eminence that is often referred to as an internal derangement. This article reviews the various presentations of internal derangements.

A Pre-Existing Myogenic Temporomandibular Disorder Increases Trigeminal Calcitonin Gene-Related Peptide and Enhances Nitroglycerin-Induced Hypersensitivity in Mice.

Migraine is commonly reported among patients with temporomandibular disorders (TMDs), especially myogenic TMD. The pathophysiologic mechanisms related to the comorbidity of the two conditions remain elusive. In the present study, we combined masseter muscle tendon ligation (MMTL)-produced myogenic TMD with systemic injection of nitroglycerin (NTG)-induced migraine-like hypersensitivity in mice. Facial mechanical allodynia, functional allodynia, and light-aversive behavior were evaluated. Sumatriptan, an FDA-approved medication for migraine, was used to validate migraine-like hypersensitivity. Additionally, we examined the protein level of calcitonin gene-related peptide (CGRP) in the spinal trigeminal nucleus caudalis using immunohistochemistry. We observed that mice with MMTL pretreatment have a prolonged NTG-induced migraine-like hypersensitivity, and MMTL also enabled a non-sensitizing dose of NTG to trigger migraine-like hypersensitivity. Systemic injection of sumatriptan inhibited the MMTL-enhanced migraine-like hypersensitivity. MMTL pretreatment significantly upregulated the protein level of CGRP in the spinal trigeminal nucleus caudalis after NTG injection. Our results indicate that a pre-existing myogenic TMD can upregulate NTG-induced trigeminal CGRP and enhance migraine-like hypersensitivity.

Burning Mouth Syndrome.

Burning mouth syndrome (BMS) is a chronic disorder for which a definitive etiopathology is not known. The BMS patient often experiences a continuous burning pain in the mouth without any clinical signs. This confusing condition can create frustration for both patient and practitioner. Ultimately, it is important for the practitioner who treats head and face pain to become knowledgeable in the recognition of the many complexities and various presentations associated with BMS. In doing so, the practitioner can be better prepared to help patients cope with this confounding disorder and gain a better quality of life.

Assessment of the Orofacial Pain Patient.

The diagnostic process of pain in the oral, facial, and head region is often perceived as more difficult due the numerous, extensively innervated structures located in this area. To successfully manage the patient with these pain presentations, it is critical for the clinician to spend ample time procuring a good medical and dental history. A systematic approach to the physical examination will ensure that sufficient data are acquired without overlooking potentially important contributing factors. The use of adjunctive laboratory tests and imaging studies should be based on the findings in the history and examination.

CRITICAL APPRAISAL. Sleep Bruxism and Sleep-Disordered Breathing.

Sleep bruxism (SB) is a repetitive jaw muscle activity with clenching or grinding of the teeth during sleep. SB is characterized by what is known as rhythmic masticatory muscle activity (RMMA). RMMA is the laboratory polysomnographic finding that differentiates SB from other oromandibular movements seen during sleep. Most often RMMA episodes are associated with sleep arousal. Some patients will report similar complaints related to both SB and sleep disordered breathing (SDB). There are some reports that would suggest that SB is a result of SDB. It has has been postulated that SB is a compensatory mechanism to re establish muscle tone of the upper airway. While these disorders do in fact often present concomitantly, the relationship between the two is yet to be fully elucidated. This Critical Appraisal reviews 3 recent publications with the intent to better define what relationships may exists between SDB and SB. While the current evidence appears to support the notion that these are often concomitant disorders, it also makes clear that evidence to support the hypothesis that SDB is causative for SB is currently lacking.

Trigger point injections for headache disorders: expert consensus methodology and narrative review.

OBJECTIVE/BACKGROUND: To review the existing literature and describe a standardized methodology by expert consensus for the performance of trigger point injections (TPIs) in the treatment of headache disorders. Despite their widespread use, the efficacy, safety, and methodology of TPIs have not been reviewed specifically for headache disorders by expert consensus. METHODS: The Peripheral Nerve Blocks and Other Interventional Procedures Special Interest Section of the American Headache Society over a series of meetings reached a consensus for nomenclature, indications, contraindications, precautions, procedural details, outcomes, and adverse effects for the use of TPIs for headache disorders. A subcommittee of the Section also reviewed the literature. RESULTS: Indications for TPIs may include many types of episodic and chronic primary and secondary headache disorders, with the presence of active trigger points (TPs) on physical examination. Contraindications may include infection, a local open skull defect, or an anesthetic allergy, and precautions are necessary in the setting of anticoagulant use, pregnancy, and obesity with unclear anatomical landmarks. The most common muscles selected for TPIs include the trapezius, sternocleidomastoid, and temporalis, with bupivacaine and lidocaine the agents used most frequently. Adverse effects are typically mild with careful patient and procedural selection, though pneumothorax and other serious adverse events have been infrequently reported. CONCLUSIONS: When performed in the appropriate setting and with the proper expertise, TPIs seem to have a role in the adjunctive treatment of the most common headache disorders. We hope our effort to characterize the methodology of TPIs by expert opinion in the context of published data motivates the performance of evidence-based and standardized treatment protocols.

Orofacial pain and headache: a review and look at the commonalities.

Headache and facial pain - in particular, temporomandibular disorders (TMDs) - are very prevalent conditions in the general population. TMDs are defined as a collection of symptoms and signs involving masticatory muscles, the temporomandibular joints (TMJs), or both. The pain reported by TMD patients is typically located in the muscles of mastication, in the preauricular area, or in the TMJs. In many cases, headaches and facial pain will occur in the same patient. Much of the research relative to the relationship of these disorders focuses on statistics of association and prevalence data. This review will provide a brief description of the types and classifications of orofacial pains (OFPs), as well as point to relevant research describing the commonalities and potential comorbid nature of these maladies. Finally, several recent papers describing morphologic changes to the brain in headache and TMD individuals will be discussed in an effort to stimulate further research into the potential common pathophysiologic mechanism that may explain the comorbid nature of these disorders.

Expert consensus recommendations for the performance of peripheral nerve blocks for headaches--a narrative review.

OBJECTIVE: To describe a standardized methodology for the performance of peripheral nerve blocks (PNBs) in the treatment of headache disorders. BACKGROUND: PNBs have long been employed in the management of headache disorders, but a wide variety of techniques are utilized in literature reports and clinical practice. METHODS: The American Headache Society Special Interest Section for PNBs and other Interventional Procedures convened meetings during 2010-2011 featuring formal discussions and agreements about the procedural details for occipital and trigeminal PNBs. A subcommittee then generated a narrative review detailing the methodology. RESULTS: PNB indications may include select primary headache disorders, secondary headache disorders, and cranial neuralgias. Special procedural considerations may be necessary in certain patient populations, including pregnancy, the elderly, anesthetic allergy, prior vasovagal attacks, an open skull defect, antiplatelet/anticoagulant use, and cosmetic concerns. PNBs described include greater occipital, lesser occipital, supratrochlear, supraorbital, and auriculotemporal injections. Technical success of the PNB should result in cutaneous anesthesia. Targeted clinical outcomes depend on the indication, and include relief of an acute headache attack, terminating a headache cycle, and transitioning out of a medication-overuse pattern. Reinjection frequency is variable, depending on the indications and agents used, and the addition of corticosteroids may be most appropriate when treating cluster headache. CONCLUSIONS: These recommendations from the American Headache Society Special Interest Section for PNBs and other Interventional Procedures members for PNB methodology in headache disorder treatment are derived from the available literature and expert consensus. With the exception of cluster headache, there is a paucity of evidence, and further research may result in the revision of these recommendations to improve the outcome and safety of these interventions.

Temporomandibular disorders, facial pain, and headaches.

Headaches and facial pain are common in the general population. In many cases, facial pain can be resultant from temporomandibular joint disorders. Studies have identified an association between headaches and temporomandibular joint disorders suggesting the possibility of shared pathophysiologic mechanisms of these 2 maladies. The aim of this paper is to elucidate potential commonalities of these disorders and to provide a brief overview of an examination protocol that may benefit the headache clinician in daily practice.

Topical review: cluster headache and sleep-related breathing disorders.

This article reviews the existing literature of the common anatomic and physiologic aspects of cluster headache and sleep-related breathing disorders to point out evidence suggesting potential therapies beneficial for both maladies. A search of PubMed, as well as relevant textbooks, was conducted using the terms cluster, headache, sleep, apnea, pain, and chronobiology to find any previously published work that may connect the two disorders. Relevant references in the literature were also investigated. As a group, cluster headache patients tend to have a higher incidence of sleep-related breathing disorders as compared to the noncluster headache population. While commonalities in anatomy and physiology exist, robust evidence linking the two disorders is currently lacking. Many people are unaware that they suffer with a sleep-related breathing disorder. The high incidence of these two disorders occurring together should prompt the clinician who treats cluster headache patients to be acutely aware that a yet undiagnosed sleep disorder may also be present.

Cerviogenic headache.

Cervicogenic headache has historically been misdiagnosed, ultimately leading to misguided therapies. Even with the growing body of literature in the field of headache, this particular entity is still vastly understudied. Efforts should be made to encourage appropriate clinical studies in order to provide evidence based therapeutic modalities for this patient population. The dental professional is provided with the unique opportunity to see these patients on a regular basis without the time constraints now shouldered by our physician colleagues. The goal of any health care provider should be to provide the most comprehensive, multi-modal and/or multidisciplinary care possible in our field of expertise. Expanding our practice model to include a more comprehensive approach to patient care has the potential to not only help an underserved population of pain patients but also provide the practitioner with the reward of heartfelt gratitude when pain relief is provided.