Size of the problem
- Percentage of population with signs – 50-75%
- Percentage of population with symptoms – 20—25%
- Percentage of population who seek treatment – 3-4%
- Women more likely to seek treatment
TMJ anatomy - condyle
Condyle
Condyle sits in fossa. Fibrous articular capsule envelopes joint which is reinforced by temporomandibular ligament
Inside the capsule is an articular biconcave disc. Disc divides joint into upper and lower compartments.
Arc of movement
Normal space between maxillary and mandibular incisors is 35-50mm. First half of opening is mainly hinging (rotation of condyle in the fossa).
Second half of opening mainly forward translation of condyle along eminence. Can see this if place own fingers over TMJ whilst opening mouth – first half, movement is imperceptible, second half can feel gliding movement.
TMJ - opening
Opening – a combination of muscle action facilitates this rotation and translation.
Geniohyoid – attaches from chin to hyoid, pulls chin down
Digastric – attaches from chin, to hyoid, back up mastoid process. Pulls chin down and backwards
Lateral pterygoid – forward translation of condyles and discs
TMJ - closing
Closing
Temporalis (posterior fibres) – backward translation of condyles
Temporalis (middle and anterior fibres), masseter and medial pterygoid elevate the mandible
Anterior part of temporalis and masseter is frequently painful on palpation, common source of symptoms.
TMJ - protrusion and retrusion
Protrusion – 10mm
Symmetrical forward translation of both condyles
Both lateral pterygoids pull condyles (and discs) forward
Retrusion
The return to rest position from the protrusion position
Both temporalis muscles (posterior fibres) pull condyles back
TMJ - lateral excursion
Lateral excursion – 10mm
The condyle on the opposite side is pulled forward
Condyle on the same side performs minimal rotation around vertical axis
Contraction of the lateral pterygoid muscles on opposite side
Combined with temporalis muscle on same side contracting to hold rest position of the condyle
Define TMD
Temporomandibular disorder (TMD) has been defined as:
• A collective term embracing a number of clinical problems that involve:
o The masticatory muscles
o The temporomandibular joint and associated structures
o Or both
Classification of common musculoskeletal TMDs (3):
Masticatory muscle disorders
Temporomandibular joint disorders
Headache
Masticatory muscle disorders:
Myalgia:
1. Local myalgia
2. Myofascial pain
3. Myofascial pain with referral
Mainly involves large closing muscles – temporalis and masseter.
Signs and symptoms:
• Familiar pain in the muscles on jaw function/parafunction, palpation and movement tests
Myofascial pain with referral:
Report of pain at a site beyond boundary of muscle being palpated
E.g. masseter – pt may report toothache, headache and earache
Awareness of referral patterns will help with differential diagnosis
Headache
Headache attributed to TMD:
Involves temporalis muscle
Signs and symptoms:
Familiar headache in temporal area on function, palpation of temporalis and movement tests
TMJ disorders (4):
Arthralgia
Disc disorders
Degenerative joint disease
Subluxation
Disc disorders (4):
- Disc displacement with reduction (DD+R)
- Disc displacement with reduction with intermittent locking (DD+R)
- Disc displacement without reduction with limited opening (DD-R)
- Disc displacement without reduction without limited opening (DD-R)
Disc displacement with reduction
Common
The disc is no longer maintained on the condyle throughout the range of motion.
Normally disc is positioned on condyle. In DD+R, the disc is displaced anteriorly.
On opening – the disc reduces, or returns back to the condyle.
At mid-range, disc reduces with a ‘click’.
On closing, disc is anteriorly displaced again, sometimes with a click.
Sometimes may find ipsilateral deviation with opening (which corrects)
Disc displacement with reduction with intermittent locking
DD + R + IL
Same as DD + R but with added:
May get intermittent TMJ locking/sticking. A manoeuvre may be required to open mouth.
Disc displacement without reduction (DD - R) + signs and symptoms
Thought to be a progression of disc displacement with reduction (DD + R)
Here the disc no longer relocates
Disc remains in front of condyle during whole opening and closing
Signs and symptoms:
Acute/subacute – ‘closed lock’ – limited mouth opening (<25mm) which interferes with pt’s ability to eat and also limited contralateral excursion
As well as familiar pain in TMJ on function, palpation or movement tests
On movement – there will be a ipsilateral deviation with opening (which doesn’t correct – because disc remains in front of the condyle throughout, this stops the condyle on RHS moving forwards so jaw swings to same side/RHS)
Disc displacement without reduction without limited opening (DD - R - LO)
Chronic – joint can become stretched to allow nearly full ROM = disc displacement without reduction without limited opening (DD-R-LO)
Degenerative joint disease
X-ray findings
Signs and symptoms
X-ray: • Joint space narrowing • Osteophytes • Subchondral sclerosis (increased opacity) • Subchondral cysts & erosions CT is the gold standard
Signs and symptoms:
Crepitus on function and movement tests
Familiar pain in the TMJ on function, palpation or movement tests
Limited mouth opening
Subluxation
Signs and symptoms
TMJ hypermobility can result in recurrent condyle subluxation (condyle goes beyond eminence)
Signs and symptoms:
TMJ clicking and locking in a wide open position
Excessive mouth opening (>50mm)
Familiar pain on function, palpation and movement tests
If the pt is able to reduce this dislocation, it is termed subluxation. If pt is unable to reduce/requires interventional reduction e.g. trip to A&E it is called luxation
Subluxation
Signs and symptoms
TMJ hypermobility can result in recurrent condyle subluxation (condyle goes beyond eminence)
Signs and symptoms:
TMJ clicking and locking in a wide open position
Excessive mouth opening (>50mm)
Familiar pain on function, palpation and movement tests
If the pt is able to reduce this dislocation, it is termed subluxation. If pt is unable to reduce/requires interventional reduction e.g. trip to A&E it is called luxation
History for TMD
- Pain - Site, Onset, Character, Radiation, Aggravating, Relieving, Timing/duration
- Clicking - On opening or closing, Aggravating/relieving, Timing, Temporary or persistent, Associated with pain
- Other joint noises
- Limitation of opening/trismus - Duration, Aggravating/relieving, Associated with pain
- Locking - On opening or closing, Timing, Temporary or persistent, Associated with pain
- Altered occlusion
- Sensory disturbance
- History of trauma
- Parafunctional activity - Clenching/grinding, Nail biting, Lip biting
Past MH for TMD
• Systemic arthritis
• Previous malignancy
• Mental health (depression/anxiety)
• Fibromyalgia
o Poorly understood condition
o Pt’s develop pain in musculature and tendons – including TMJ
o Likely these pt’s have a reduced threshold to developing pain when overusing muscles almost like these pt’s have low pain threshold – develop pain v quickly when overusing muscles
o Widespread pain and sensitivity to palpation at multiple anatomically defined tissue sites
o Often accompanied by depression and insomnia
o Thought to be due to CNS neurosensory amplification
• Hypermobility syndrome
o Very hypermobile
o Because of this, are more likely to stretch joints and experience TMD
Red flags for TMD
- History of cancer (may suggest metastasis)
- Pain that is abrupt in onset, severe or precipitated by exertion, coughing, or sneezing or that interrupts sleep (mays suggest intracranial pathology or cardiac ischaemia)
- Weight loss (may suggest cancer)
- Fever (may suggest septic arthritis, osteomyelitis, intracranial abscess, tooth abscess or mastoiditis)
- Neurological symptoms or signs (may suggest a tumour or other intracranial pathology)
- Swelling of the temporo-mandibular joint, mandible, parotid gland (may suggest tumour, infection or inflammatory arthropathy)
- Facial asymmetry (may indicate a tumour)
- Unilateral headache or scalp tenderness, jaw claudication or symptoms (suggests giant cell arthritis)
- Nasal symptoms – persistent loss of smell (anosmia), purulent discharge, nasal blockage or epistaxis (may suggest nasopharyngeal tumour)
- Neck mass or persistent cervical lymphadenopathy (may suggest tumour or infection)
- Change in occlusion (how teeth meet together when the jaws are closed). This may suggest a tumour or bone growth (for example acromegaly) around the temporo-mandibular joint, or inflammatory arthritis – but can also be seen in other TMD disorders
- Decreased hearing on the ipsilateral side (may suggest nasopharyngeal carcinoma)
- Increasing pain or limitation in function despite initial management (may suggest a tumour)
TMD advice
- As other musculoskeletal problems
- Rest
- Elevate
- Ice
- Strapping
- Physiotherapy
- Analgesia
- Avoid things that aggravate pain
Social history – chewing gum, stress, lip biting, nail biting, hair biting,
