Trismus Causes: High-yield Dental Notes

Trismus Causes: High-yield Dental Notes

Greek word “ Trismus” means “gnashing” 

It is defined as prolonged, tetanic spasm of the jaw muscles by which normal opening of the mouth is restricted.

Normal mouth opening range 35-50mm

Closing muscles are 10 times more powerful than opening muscle. It explains why relative weakness of opening musculature cause trismus.

Causes:

1.Congenital causes of trismus

• Trismus pseudocamptodactyly syndrome
• Arthrogynposis multiplex congenita
• Craniocarpo tarsal dysplaisa
• Hemifacial microsomia
• Fibrodysplasia ossificans progressiva
• Popliteal pterygium syndrome
• Birth injury
• Hypertrophy of coronoid

2. Trauma

• Fracture of mandible, zygomatic bone, temporal bones
• Hematomas in the joint of muscles of mastication 
• Foreign body
• Local anesthetic injection injury
• Paradoxical muscle spasm following head injury
• Anterior dislocated meniscus
• Post surgical (3rd molar, TMJ)

3. Trismus causes: Neoplastic (Benign)

• Mesenchymal tumors of the TMJ and surrounding structure (osteochondroma)
• Enlargement of the coronoid process of the mandible

4. Neoplastic (malignant)

• Chrondrosarcoma
• Osteosarcoma
• Tumor of the Brain stem
• Trotter’s syndrome
• Metastatic disease of mandible and infratemporal fossa

Mnemonic: “Bad TOM Cat“

• Brain stem tumor
• Trotter’s syndrome
• Osteosarcoma
• Metastatic disease of mandible & infratemporal fossa
• Chondrosarcoma

5. Neuromusclular disorder

Parkinson’s disease

6. Infection

A. Odontogenic Trismus causes- 

• Pulpal
• Periodontal
• Pericoronal 

B. Non-odontogenic Trismus causes-

• Tonsilitis or peritonsilar abscess
• Septic arthritis
• Tetanus
• Osteomyelitis of mandible and temporal bone
• Abscess of submasseteric, lateral pharyngeal pterygomandibular, submandibular and temporal space.
• Parotid abscess
• Mumps
• Cancrum oris
• Encephalitis 
• Meningitis

7. Reactive 

• TMJ ankylosis (fibrous & bony)
• Degenerative joint disease
• Rheumatoid arthritis
• Systemic sclerosis
• OSMF
• Soft tissue fibrosis
• Polymyositis
• Radiation therapy
• MPDS
• Ankylosing spondylitis
• Multifocal idiopathic fibrosis
• Myositis ossificans

8. Psychogenic causes of trismus

• Hysterical trismus
• Hyperventilation syndrome

9. Drug induced

• Phenothiazine
• Succinyl choline
• Tricyclic antidepressant
• Metaclopramide
• Halothane

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