The jaw click: a common symptom with a frequently overlooked cause

Clicking or popping when opening and closing the mouth is one of the most prevalent symptoms of temporomandibular disorder (TMD) — a term that encompasses disorders of the temporomandibular joint (TMJ), the masticatory musculature, and adjacent structures. It affects between 5% and 12% of the population to some degree, with higher incidence in women between 20 and 40 years old, and is frequently underdiagnosed because patients do not associate the jaw click with the headache, facial pain, or sensation of \"plugged ear\" that accompanies it.

The temporomandibular joint is one of the most complex joints in the body: it is biaxial (allows opening, closing, protrusion, and laterality), and contains a fibrocartilaginous articular disc interposed between the mandibular condyle and the mandibular fossa of the temporal bone. The click occurs when this disc is anteriorly displaced and returns to position during opening — what is called disc displacement with reduction. When the disc remains permanently displaced, locking of the jaw occurs.

Functional anatomy of TMD and the muscles involved

  1. Masseter

    The masseter is the most powerful muscle in the body relative to its size — generating bite forces of up to 700 N. In patients with bruxism, this muscle works during sleep generating repetitive forces that exceed joint tolerance. Its trigger points refer pain to the jaw, upper teeth, temple, and ear. Masseter hypertrophy from bruxism is visible as a "belly" in the lateral mandibular region.

  2. Temporalis

    The temporalis muscle (a fan over the temple) elevates and retracts the mandible. Its trigger points refer pain to the upper teeth and forehead — frequently mistaken for migraine or unexplained dental pain. It is intensely activated in bruxism and unilateral chewing.

  3. Medial and lateral pterygoid

    The pterygoids are deep muscles of the infratemporal fossa. The superior lateral pterygoid inserts on the articular disc and condyle — its hypertonia pulls the disc out of position, generating the anterior displacement. The inferior lateral pterygoid produces protrusion and opening of the mandible. Their trigger points refer deep pain to the TMJ and ear. They are accessible to needling via the intraoral or extraoral route by a trained physician.

  4. Electroacupuncture and muscular balance

    Electroacupuncture at points SI19, GB2, ST6, ST7 (over the TMJ and masseter) and at the pterygoids may contribute to relaxation of the masticatory musculature, with the hypothesis of reducing TMJ synovial inflammation and modulating the central sensitization involved in chronic pain. Combined with an occlusal splint for nocturnal joint protection, it forms an integrated approach for moderate to severe TMD.

Clinical and epidemiologic data on TMD

5–12%
OF THE POPULATION
have clinically significant TMD — most never receive a correct diagnosis and treat symptoms in isolation (analgesics for headache, root canal without dental cause)
80%
OF TMD CASES
have a significant contribution from sleep bruxism — which generally occurs without the patient noticing and is only confirmed by polysomnography or by the partner’s report
~70%
PAIN REDUCTION
described in randomized studies of electroacupuncture in the masticatory muscles — with preliminary evidence of results superior to placebo and comparable, in selected series, to treatment with an occlusal splint alone; methodologic heterogeneity still limits robust meta-analyses
3x
MORE FREQUENT
in women than in men — possibly due to hormonal differences (estrogen increases TMJ sensitivity) and a greater tendency to bruxism under stress

Recognizing TMD: typical clinical pattern

Critérios clínicos
08 itens

Symptoms that indicate TMD

  1. 01

    Clicking or popping when opening or closing the mouth — especially on waking

  2. 02

    Pain or sense of fatigue in the jaw muscles when chewing

  3. 03

    Limitation of mouth opening (difficulty biting a hamburger or yawning)

  4. 04

    Headache in the temples, especially in the morning

  5. 05

    Sensation of a "plugged ear" or tinnitus without otologic cause

  6. 06

    Pain in the upper teeth without an identified dental cause

  7. 07

    Lateral deviation of the jaw on opening the mouth

  8. 08

    Involuntary clenching of the teeth under stress (daytime bruxism)

Myths and facts about TMD

Myth vs. Fact

MYTH

A clicking jaw is normal and does not need treatment

FACT

A painless and stable click for years can indeed be tolerated without treatment. However, a click accompanied by pain, limitation of opening, headache, or a sense of locking indicates disc displacement with joint overload — and early treatment prevents progression to TMJ osteoarthritis, which is irreversible.

MYTH

TMD is treated only by the dentist with an occlusal splint

FACT

The occlusal splint protects the teeth and the TMJ from excessive forces, but does not treat the muscular hypertonia — the muscular component of TMD. Medical electroacupuncture in the pterygoids, masseter, and temporalis is the most effective treatment for the myofascial component, and the medical acupuncturist can work together with the dentist for a complete result.

MYTH

Ear pain in TMD is an ear infection

FACT

The TMJ is in direct contact with the external auditory canal — separated only by a thin bony wall. Trigger points in the lateral pterygoid and masseter refer pain exactly to the inside of the ear. Patients with TMD are frequently diagnosed and treated for otitis without relief, until the joint cause is identified.

Integrated medical treatment protocol

Clinical and functional diagnosis
1st visit

Assessment of mouth opening (normal: 40–55 mm). Palpation of the TMJ during opening/closing — identification of clicking, crepitus, deviation. Palpation of the masticatory muscles: masseter, temporalis, pterygoids (intraoral and extraoral). Assessment of bruxism: dental wear, bite, report of clenching. If available: request for TMJ MRI to assess disc position.

Electroacupuncture in the masticatory muscles
Sessions 1–4

Needling at points SI19, GB2, ST6, ST7 in the TMJ region. Dry needling of trigger points in the masseter and temporalis. Needling of the lateral pterygoid via the extraoral route (specialized medical approach). Electroacupuncture at 2 Hz for 20 minutes — analgesia and muscle relaxation. Pain relief and increased mouth opening may be perceived in some patients as early as the first sessions.

Coordination with dentistry
Weeks 3–6

Recommendation of a relaxation occlusal splint for nighttime use (made by the dentist) — TMJ protection during nocturnal bruxism. Continuation of medical acupuncture for the muscular component. For refractory cases: medical Botox in the masseter to reduce bruxism force — a medical procedure, not a dental one.

Maintenance and bruxism control
Months 2–3

Biweekly or monthly maintenance sessions. Stress-control techniques — the main trigger of bruxism. In cases with documented sleep bruxism: assessment of polysomnography to screen for associated obstructive sleep apnea (bruxism secondary to apnea is treated with CPAP, not just with a splint).

Clinical pearl: medical Botox in the masseter

Frequently asked questions

FREQUENTLY ASKED QUESTIONS · 03

Frequently Asked Questions

It depends. A stable, painless click can remain so for decades. However, if there is associated pain, progressive limitation of opening, or a sense of locking, progression to TMJ osteoarthritis is possible without treatment. Disc displacement with reduction (which causes the click) can evolve into displacement without reduction (locking) — better to treat while there is still a click than to wait for locking.

Medical acupuncture does not mechanically reposition the disc — that requires surgical intervention in severe cases or specific articular manipulation techniques. What acupuncture does is reduce muscular hypertonia (especially of the lateral pterygoid, which pulls the disc anteriorly), reduce synovial inflammation, and modulate pain. With balanced musculature, the disc frequently finds a better position spontaneously.

Points SI19, GB2, and ST7 in the TMJ region are needled with fine needles — most patients describe a sense of pressure or mild numbness, not severe pain. Electroacupuncture with low-frequency current (2 Hz) generates a sensation of gentle vibration. Needling of the lateral pterygoid is the most intense, but performed with precise technique by a trained physician, it is tolerated in the great majority of cases.