Temporal–mandibular Joint Injury/syndrome
Basics
Basics
Basics
Description
Description
- Myofascial pain causing temporomandibular joint (TMJ) dysfunction
- Prevalence of 40–75% of 1 sign of TMJ disorder
- Most common in 18–44 yr olds
- Higher prevalence in women by 1.5×
- 40% have symptoms that resolve spontaneously
- TMJ is a synovial joint:
- Allows for hinge and sliding movements
- Normal range is 35–55 mm (maxillary to mandible incisors)
- Articular disorders:
- Congenital or developmental
- Degenerative joint disorders:
- Inflammatory (rheumatoid arthritis)
- Noninflammatory (osteoarthritis)
- Trauma
- TMJ hypermobility:
- Laxity
- Dislocation
- Subluxation
- TMJ hypomobility:
- Infection
- Neoplasm
- Masticatory muscle disorders:
- Local myalgias
- Myositis
- Muscle spasm
- Contracture
- Myofascial pain disorder
- TMJ clicking:
- May be normal finding; present as a transient finding in 40–60% of the population
- TMJ motion: Limited by adhesions within the joint or disk displacement or trismus from muscle spasm
- Intra-articular disk disorder:
- Anterior displacement with reduction:
- Displacement in closed mouth position
- Often with a click and variable pain with opening mouth
- May worsen over time
- Anterior disk displacement without reduction:
- Disk is a mechanical obstruction to opening mouth
- Maximal opening may be limited to 20–25 mm
- Often difficult to correct
Etiology
Etiology
TMJ dysfunction is poorly understood:- Multifactorial:
- Bruxism (teeth grinding)
- Trauma
- Malocclusion
- Onset can be related to stress
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