significant diagnostic sensitivity, us has inadequate specificity when identifying osteoarthrosis. moreover, it is not accurate enough for the diagnosis of cortical and articular disc morphology based on the findings done related to morphological alterations. however, with us, identification of effusion in individuals with inflammatory conditions associated with pain is possible and confirmed by mri us can be a useful alternative in initial investigation of internal tmj dysfunctions especially in mri contraindicated individuals despite its limitations. in addition to being less costly, us provides a quick and comfortable real-time imaging without exposing the individual to ionizing radiation us is commonly assessed in the differential diagnosis of alterations of glandular and neighbouring structures, such as the tmj and the masseter muscle. symptoms of sialendenitis and sialothiasis cases can be confused with eagle syndrome, tmd, myofascial and nerve pain, and other pain of the orofacial region. us assessment is also indicated where there is need to identify the correct position of the joint spaces for infiltrative procedures, arthrocentesis, and viscosupplementation. this is due to the fact that us provides a dynamic and real-time location of the component of the joints, while providing adequate lubrication and washing, which can be confirmed by the joint space increase post-treatment. management tmd can be difficult to manage, and since the disorder transcends the boundaries between several health-care disciplines – in particular, dentistry and neurology, the treatment may often involve multiple approaches and be multidisciplinary. most who are involved in treating and researching tmd now agree that any treatment carried out should not permanently alter the jaw or teeth, and should be reversible. to avoid permanent change, over-the-counter or prescription pain medications may be prescribed. psychosocial and behavioral interventions given the important role that psychosocial factors appear to play in tmd, psychosocial interventions could be viewed to be central to management of the condition. there is a suggestion that treatment of factors that modulate pain sensitivity such as mood disorders, anxiety and fatigue, may be important in the treatment of tmd, which often tends to attempt to address the pain directly. cognitive behavioral therapy (cbt) has been used in tmd and has been shown to be efficacious by meta analyses. hypnosis is suggested by some to be appropriate for tmd. studies have suggested that it may even be more beneficial than occlusal splint therapy, and has comparable effects to relaxation techniques. relaxation techniques include progressive muscle relaxation, yoga, and meditation. it has been suggested that tmd involves increased sensitivity to external stimuli leading to an increased sympathetic ("fight or flight") response with cardiovascular and respiratory alterations. relaxation techniques cause reduced sympathetic activity, including muscle relaxation and reducing sensitivity to external stimuli, and provoke a general sense of well-being and reduced anxiety. devices a lower, full coverage occlusal splint after 8 years in use. an upper, full coverage occlusal splint. occlusal splints (also termed bite plates or intra-oral appliances) are often used by dentists to treat tmd. they are usually made of acrylic and can be hard or soft. they can be designed to fit onto the upper teeth or the lower teeth. they may cover all the teeth in one arch (full coverage splint) or only some (partial coverage splint). splints are also termed according to their intended mechanism, such as the anterior positioning splint or the stabilization splint. although occlusal splints are generally considered a reversible treatment, sometimes partial coverage splints lead to pathologic tooth migration (changes in the position of teeth). normally splints are only worn during sleep, and therefore probably do nothing for people who engage in parafunctional activities during wakefulness rather than during sleep. there is slightly more evidence for the use of occlusal splints in sleep bruxism than in tmd. a splint can also have a diagnostic role if it demonstrates excessive occlusal wear after a period of wearing it each night. this may confirm the presence of sleep bruxism if it was in doubt. soft splints are occasionally reported to worsen discomfort related to tmd. specific types of occlusal splint are discussed below. a stabilization splint is a hard acrylic splint that forces the teeth to meet in an "ideal" relationship for the muscles of mastication and the tmjs. it is claimed that this technique reduces abnormal muscular activity and promotes "neuromuscular balance". a stabilization splint is only intended to be used for about 2–3 months. it is more complicated to construct than other types of splint since a face bow record is required and significantly more skill on the part of the dental technician. this kind of splint should be properly fitted to avoid exacerbating the problem and used for brief periods of time. the use of the splint should be discontinued if it is painful or increases existing pain. a systematic review of all the scientific studies investigating the efficacy of stabilization splints concluded the following: "on the basis of our analysis we conclude that the literature seems to suggest that there is insufficient evidence either for or against the use of stabilization splint therapy over other active interventions for the treatment of tmd. however, there is weak evidence to suggest that the use of stabilization splints for the treatment of tmd may be beneficial for reducing pain severity, at rest and on palpation, when compared to no treatment". partial coverage splints are recommended by some experts, but they have the potential to cause unwanted tooth movements, which can occasionally be severe. the mechanism of this tooth movement is that the splint effectively holds some teeth out of contact and puts all the force of the bite onto the teeth which the splint covers. this can cause the covered teeth to be intruded, and those that are not covered to over-erupted. i.e. a partial coverage splint can act as a dahl appliance. examples of partial coverage splints include the nti-tss ("nociceptive trigeminal inhibitor tension suppression system"), which covers the upper front teeth only. due to the risks involved with long term use, some discourage the use of any type of partial coverage splint. an anterior positioning splint is a splint that designed to promote an anteriorly displaced disc. it is rarely used. a 2010 review of all the scientific studies carried out to investigate the use of occlusal splints in tmd concluded: "hard stabilization appliances, when adjusted properly, have good evidence of modest efficacy in the treatment of tmd pain compared to non-occluding appliances and no treatment. other types of appliances, including soft stabilization appliances, anterior positioning appliances, and anterior bite appliances, have some rct evidence of efficacy in reducing tmd pain. however, the potential for adverse events with these appliances is higher and suggests the need for close monitoring in their use." ear canal inserts are also available, but no published peer-reviewed clinical trials have shown them to be useful. medication medication is the main method of managing pain in tmd, mostly because there is little if any evidence of the effectiveness of surgical or dental interventions. many drugs have been used to treat tmd pain, such as analgesics (pain killers), benzodiazepines (e.g. clonazepam, prazepam, diazepam), anticonvulsants (e.g. gabapentin), muscle relaxants (e.g. cyclobenzaprine), and others. analgesics that have been studied in tmd include non-steroidal anti-inflammatory drugs (e.g. piroxicam, diclofenac, naproxen) and cyclo-oxygenase-2 inhibitors (e.g. celecoxib). topical methyl salicylate and topical capsaicin have also been used. other drugs that have been described for use in tmd include glucosamine hydrochloride/chondroitin sulphate and propranolol. low-doses of anti-muscarinic tricyclic antidepressants such as amitriptyline, or nortriptyline have also been described. despite many randomized control trials being conducted on these commonly used medications for tmd a systematic review carried out in 2010 concluded that there was insufficient evidence to support or not to support the use of these drugs in tmd. in a subset of people with tmd who are not helped by either noninvasive and invasive treatments, long term use of opiate analgesics has been suggested, although these drugs carry a risk of drug dependence and other side effects. examples include morphine, fentanyl, oxycodone, tramadol, hydrocodone, and methadone. injections of local anesthetic, sometimes combined with steroids, into the muscles (e.g. the temoralis muscle or its tendon) are also sometimes used. local anesthetics may provide temporary pain relief, and steroids inhibit pro-inflammatory cytokines. steroids and other medications are sometimes injected directly into the joint (see intra-articular injections). botulinum toxin solution ("botox") is sometimes used to treat tmd. injection of botox into the lateral pterygoid muscle has been investigated in multiple randomized control trials, and there is evidence that it is of benefit in tmd. it is theorized that spasm of lateral pterygoid causes anterior disc displacement. botulinum toxin causes temporary muscular paralysis by inhibiting acetylcholine release at the neuromuscular junction. the effects usually last for a period of months before they wear off. complications include the creation of a "fixed" expression due to diffusion of the solution and subsequent involvement of the muscles of facial expression, which lasts until the effects of the botox wear off. physiotherapy physiotherapy (physical therapy) is sometimes used as an adjuvant to other methods of treatment in tmd. there are many different approaches described, but exercises aiming to increase the range of mandibular movements are commonly involved. jaw exercises aim to directly oppose the negative effects of disuse that may occur in tmd, due to pain discouraging people from moving their jaw. after initial instruction, people are able to perform a physical therapy regimen at home. the most simple method is by regular stretching within pain tolerance, using the thumb and a finger in a "scissor" maneuver. gentle force is applied until pain of resistance is felt, and then the position is held for several seconds. commercial devices have been developed to carry out this stretching exercise (e.g. the "therabite" appliance). over time, the amount of mouth opening possible without pain can be gradually increased. a baseline record of the distance at the start of physical therapy (e.g. the number of fingers that can be placed vertically between the upper and lower incisors), can chart any improvement over time. it has been suggested that massage therapy for tmd improves both the subjective and objective health status. "friction massage" uses surface pressure to causes temporary ischemia and subsequent hyperemia in the muscles, and this is hypothesized to inactivate trigger points and disrupt small fibrous adhesions within the muscle that have formed following surgery or muscular shortening due to restricted movement. occasionally physiotherapy for tmd may include the use of transcutaneous electrical nerve stimulation (tens), which may override pain by stimulation of superficial nerve fibers and lead to pain reduction which extends after the time where the tens is being actually being applied, possibly due to release of endorphins. others recommend the use of ultrasound, theorized to produce tissue heating, alter blood flow and metabolic activity at a level that is deeper than possible with surface heat applications. there is tentative evidence that low level laser therapy may help with pain. the goals of a pt in reference to treatment of tmd should be to decrease pain, enable muscle relaxation, reduce muscular hyperactivity, and reestablish muscle function and joint mobility. pt treatment is non-invasive and includes self-care management in an environment to create patient responsibility for their own health. therapeutic exercise and manual therapy (mt) are used to improve strength, coordination and mobility and to reduce pain. treatment may focus on poor posture, cervical muscle spasms and treatment for referred cervical origin (pain referred from upper levels of the cervical spine) or orofacial pain . mt has been used to restore normal range of motion, promoting circulation, stimulate proprioception, break fibrous adhesions, stimulate synovial fluid production and reduce pain. exercises and mt are safe and simple interventions that could potentially be beneficial for patients with tmd. no adverse events regarding exercise therapy and manual therapy have been reported. there have been positive results when using postural exercises and jaw exercises to treat both myogenous (muscular) and arthrogenous (articular) tmj dysfunction. mt alone or in combination with exercises shows promising effects. it is necessary that trials be performed isolating the type of exercise and manual techniques to allow a better understanding of the effectiveness of this treatment. additionally, details of exercise, dosage, and frequency as well as details on manual techniques should be reported to create reproducible results. high quality trials