Management of myofascial pain: a systematic review

Objective: To investigate the current treatment on myofascial pain in


Introduction
The Epidemiological studies have shown that 75% of the population have at least one TMD sign and 33% at least one symptom. 1 The etiology of myofascial pain is known for multiple factors including psychological factors, occlusion imbalance, parafunctional habits, hereditary factors and psychological factors of sysemic. Some of the patient's symptoms such as headache, facial pain and neck and limitations open mouth. 2 The vicious cycle theory shows a triggering factor of myofascial pain as a muscle that is often used which results in a reflex of pain causing fatigue and muscle spasms. In general, patients with myofascial pain disorder have difficulty in the process of mastication hard food or chewy. 3 The pathogenesis of TMJ disease, however, is still being investigated. Major elements identified in this multifactorial disease process include trauma and joint overloading (e.g. bruxism), hypoxia-reperfusion cycles, oxidative injury, accumulation of inflammatory mediators in the synovial fluid (ie. PGs, LTs, ILs, and TNF-alpha), psychological factors (i.e. anxiety and depression), stress, genetic alterations (i.e. connective tissue mutations), hormonal factors, low pain thresholds, inadequate pain modulation, and others. 4 The first step in the clinical management of temporomandibular disorders is to distinguish the source a problem, classifying into a problem of muscle or joint, which has been understood to be an important process. Although the exact mechanism for the symptoms or pathology of these conditions has not yet been clarified, muscle parafunction or hyperfunction has been recognized to play an important role in the etiology of TMD. 5 Many treatment modalities have been described for the treatment of musculoskeletal disorders. In the case of TMD, the treatments available vary according to the involvement of muscle and joint structures, to the clinical signs and to the onset of the problem. The treatments of choice are usually conservative and reversible and involve education and counseling of the patients, cognitive behavioral therapy, pharmacotherapy, use of interocclusal devices and physiotherapy, normally used in a combined way depending on the TMD diagnosis. The treatment goal for patients with myofascial pain aims to control pain and to recover masticatory function. 6 This study provides a description, alternative and effective treatment of myofascial pain associated with TMD over the past 5 years.

Methods
The systematic review is written using the PRISMA guidelines (Preferred Reporting Items for Systematic reviews and Meta-Analyzes), using PICO question (population, intervention, control, outcome) in systematic review: management of myofascial pain.
Kriiteria Inklusi; articles in English, any research study published between January 2013 to December 2017, research that explains treatment / management myofascial associated with TMD, comply the criteria in PICO questions, the author gets a full text journal, keywords used relate to temporomandibular disorders. Kriteria Eklusi; all of which are not included in the inclusion criteria, journals that by systematic review method.
Search using the "management" or "treatment" and "Myofascial Pain" or "Myofascial Pain Syndromes" and "temporomandibular" keywords on Pubmed and wiley search engines. As shown in figure 1, there are 77 journals in pubmed and 9 journals on wiley but there are 2 journals that have the same title on both search engines totaling 84 journals. After screning on title and abstract there are 21 journals with expected inclusion criteria and 64 journals with exclusion criteria. There are

Results
The results of systemic analysis showed that most of myofascial pain suffered by women 94% (n = 385) than males 6% (n = 23). However, some journals also have no research subjects in their study figure 2. Muscles involved in 17 journals as much as 80% (n = 12) in masseter and temporal muscles, 20% (n = 3) were only temporal muscle and there was not masseter muscle involved but 3 study not availabe were muscle involved figure 3.
It was reported that 7 treatments were performed in 5 years ago. The use of low-level laser therapy is mostly used 41% (n = 7), treatment with drugs (Botulinum toxin A, tizanidine, ciclobenzaprine, melatonin) amount 23% (n = 4), occlusal device therapy as much as 17% (n = 3) and dry needle, masseter nerve block, massage on temporal and mass muscl severally 1 report figure 4.  The simultaneous use of occlusal devices appears to produce an earlier improvement.

Discussion
In the last 30 years, there has been growing interest in investigating the effects of low laser therapy and its various clinical applications in different medical specialties, as either a single or a complementary therapy. 7 Low Level Laser Therapy is a non-pharmacological therapeutic modality that is easy to apply, safe, and affordable. A meta-analysis published in 2015 provides the best current evidence effectiveness in the treatment of TMD. The Low Level Laser Therapy has proven to have anti-inflammatory and analgesic effects when applied in specific regions, such as the inflamed TMJs of rats. 1 another study report that Low-level laser therapy is frequently used to treat various pain associated conditions, including musculosketal pain disorders, because of its analgesic, myorelaxant, tissue-healing and biostimulation effects. 8 In other studies the laser therapy showed an effects which demonstrated, such as the release of endogenous opioids, reduction in the production of COX-2 and prostaglandin, lymphocyte metabolism and the secretion of histamine, kinins and cytokines, such as TNF-α, IL-β, IL-6, and TGF-β. 9 The 4 study reported using teratment of drugs (Botulinum toxin A, tizanidine/cyclobenzaprine, analgesic melatonin). Non-surgical treatment modalities (i.e. soft diet, NSAIDs, oral appliances, etc.) represent the first line of treatment for temporomandibular disorders. The benefits of using botulinum toxin A for myofascial pain in the setting of temporomandibular disorders include minimal administration time, proven reduction in bite force, potential reduction in pain score, and low risk of complications. The disadvantages include cost (although comparable to occlusal appliance therapy and physical therapy), unpredictable response, and possible need for repeat injections. 4 Tizanidine acts as a central muscle relaxant. It has been demonstrated in animal studies that doses below those required for producing muscular relaxation have an antinociceptive effect. 10 Cyclobenzaprine has effects similar to those of tricyclic antidepressants on the improvement of sleep quality and pain, with an additional muscle relaxant effect. 11 The occlusal device therapy is a noninvasive and reversible biomechanical method commonly used for myofascial pain treatment and had been reported to decrease pain symptoms between 70% and 90%. Its may increase the vertical dimension, thereby reducing the load on the TMJ structures,   which eliminates occlusal interferences and increases peripheral input to the central nervous system. 3 General practitioners claim that adjustment of a stabilisation appliance is a difficult and time-consuming procedure. It is therefore of interest to find an easier procedure for fabricating an appliance that has the same effectiveness as the stabilisation appliance. 12 Different conservative treatments deep dry needling in which a solid filament needle is inserted into the myofascial trigger points. Applied dry needling with intramuscular stimulation of temporalis and masseter in patients with myofascial TMD pain and observed immediate improvements in pain and tenderness, but not pain-free maximal jaw opening. 13 The therapeutic effect of the block appeared to outlast the duration of the action of the local anesthetic effect in patients. However, Side effects of masseteric nerve block can temporary loss of contraction of the orbicularis oculi muscle on the side of the block, bruising and infection. local anesthetic effect may temporarily impair both the sensory and the motor innervation to the muscle. The masseter was selected because the masseter is a single muscle, and the masseteric nerve is easily accessible. 14 Massage is one of methods of physical therapy. Massage repeatedly compresses muscles, drains pain mediators to the lymphatic system, and stimulates blood circulation. it effectively reduces muscle swelling, restores the normal osmotic pressure of interstitial fluid, and thus reduces muscle edema. Massage improves muscle imbalance, and then relieves pain, and improves mouth opening. 15 This study showed more female than male diagnosed myofascial pain related to several hypotheses in the literature about the high prevalence of TMD, such as hormonal and bio-behavioral factors. This is suported with Silveira, et al. found the index percentage of females with TMD to be higher than males. (16) The masseter and temporalis have been found to be the most prevalent muscles presenting active MTrPs in patients with myofascial TMD. 13 This study had some limitations, the source of the references obtained in the last 5 years using only 2 search enggine journals and this study did not discuss characteristic about each treatment performed.

Conclusion
Based on published systematic review for the last 5 years from pubmed and willey serach enggine, the low laser therapy is the most treatment used.
The both of masseter and temporalis muscle are involved on myofascial pain and the number of patients with myofascial pain most female than male.