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The TMJ or temporomandibular joint is the bilateral hinge that connects the jaw to the skull, allowing the opening, closing, protrusion, retrusion, and lateral movements necessary for chewing, speaking, yawning, and swallowing.
The TMJ is one of the most complex and active joints in the human body: it moves more than two thousand times a day through chewing and speech alone. When this joint does not function correctly, the impact on daily life is immediate: pain when eating, clicking when opening the mouth, morning headaches, and a feeling of clogged ears are signs that should not be ignored.
At Asensio Dental Clinic, Dr. Lucía Asensio Romero (Registration No. 46002287) is a specialist in the diagnosis and treatment of TMJ pathologies in Valencia. If you have any of these symptoms, consult our TMJ dysfunction in Valencia page. The first visit is completely free.
What is Costen’s Syndrome?
Costen’s syndrome was first described in 1934 by otolaryngologist James Costen, who observed that many of his patients with otological symptoms —ear pain, clogging, tinnitus— improved when their bite was treated. Today it is used as a synonym for temporomandibular dysfunction to describe the set of symptoms that appear when the TMJ does not work correctly: pain in the preauricular area, joint clicking, restricted jaw opening, and pain radiating to the head, neck, and ear.
The central pathophysiological mechanism is the displacement or degeneration of the articular disc — a fibrocartilaginous structure interposed between the mandibular condyle and the temporal bone that acts as a shock absorber. When the disc moves forward —anterior disc displacement— the condyle loses its center of rotation and rubs directly against the temporal bone, generating characteristic clicks and pain. If the displacement progresses without treatment, a closed lock —the jaw cannot open fully— or an open lock —the jaw remains stuck in an open position— can occur.
| Cause | Mechanism |
|---|---|
| Dental malocclusion | Alteration of the occlusion that generates chronic overload on the TMJ |
| Bruxism | Permanent tension in muscles and ligaments due to nighttime clenching |
| Trauma | Direct impacts or repeated microtrauma to the jaw |
| Stress and emotional tension | Sustained muscle contractures induced by tension |
The diagnosis of Costen’s syndrome combines clinical examination with panoramic X-rays and MRI when indicated, allowing for the identification of disc displacements, bone erosions, or inflammatory changes. Early treatment prevents pain from becoming chronic and restores masticatory function before irreversible joint damage occurs.
TMJ Treatment with Botox
TMJ treatment with botulinum toxin —popularly known as Botox— is one of the most effective therapeutic options for cases where the muscle component is predominant. Botulinum toxin injections into the masseter and temporal muscles reduce their excessive contractile activity in a controlled and reversible manner, relieving pressure on the joint, muscle pain, and associated headaches.
The mechanism of action of Botox in the TMJ is the reversible inhibition of acetylcholine release at the neuromuscular junction, which produces partial and temporary muscle paralysis. The muscle does not disappear or atrophy permanently: it simply reduces its tone and maximum contraction capacity during the effect period, which ranges between three and six months. After this time, the muscle gradually recovers its activity and it may be necessary to repeat the treatment according to the patient’s evolution.
The protocol at Asensio Dental Clinic includes a prior evaluation through muscle palpation and electromyography to locate hyperactive muscles and quantify their degree of activation. Trigger points for each muscle are identified, topical anesthesia is applied to maximize comfort, and precise doses of botulinum toxin are injected with ultrafine needles. The effect begins to be felt between 3 and 7 days after treatment, with a progressive reduction in muscle tension and pain.
Mandibular pain reduction with Botox is especially appreciated by patients with severe bruxism who do not tolerate bite guards or who do not obtain sufficient relief from them. It is also indicated in patients with masseteric hypertrophy —thickening of the masseter muscle due to chronic bruxism— which produces a visible widening of the jaw. In these cases, Botox treatment also has an aesthetic effect of slimming the facial contour.
| Benefit of Botox in TMJ | Description |
|---|---|
| Pain reduction | Decreases pressure and tightness in the jaw, relieving headaches and facial pain |
| Function improvement | Increases the range of mouth opening by reducing muscle spasm |
| Prevention of joint wear | Reduces mechanical friction that worsens inflammation and disc deterioration |
| Therapeutic complement | Combined with bite guards and physiotherapy for optimal results |
Frequently asked questions about TMJ
What is the difference between TMJ and TMJ dysfunction?
The TMJ is the joint itself — an anatomical structure present in everyone. TMJ dysfunction is the pathology that occurs when this joint does not function correctly, causing pain, clicking, or limited movement. For dysfunction treatment, consult our TMJ specialists in Valencia page.
Is Botox for TMJ permanent?
No. The effects of Botox on the masticatory muscles last between 3 and 6 months. After that time, the muscle gradually recovers its activity and it may be necessary to repeat the treatment. Over time, some patients manage to space out the sessions more and more.
Can TMJ be treated without surgery?
Yes, in most cases. Conservative treatments —bite guards, physiotherapy, Botox, and anti-inflammatory medication— resolve the problem in a high percentage of patients. Surgery is reserved for severe cases that do not respond to conservative treatments.