- Primary: is caused by the normal joint wear associated with aging. It usually begins in the 5th decade.
- Secondary: is frequently caused by acute trauma. It is often seen in patients 20-40 years.
- Females:males is about 7:1
- Symptoms: pain or tenderness in the joint and masticatory muscles, reduced range or deviating jaw function, and crepitus during mandibular movements.
- Radiographic features: Subchondral sclerosis of the condylar head – Flattening of the head of the condyle- Irregular cortical outlines- Cortical erosions and subchondral cystlike erosions- Osteophyte formation- Reduced joint space- bony contact with mouth open- Flattening and enllargment of the glenoid fossa.
Osteoarthritis (degenerative arthritis)
Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted through the bite of infected blacklegged ticks. If left untreated, the infection can spread to the joints causing arthritis with severe pain and swelling (mostly unilateral)
Severe Osteoarthritis of the Right TMJ. Reduced joint space, flattening of the head of the condyle, Cortical erosions and subchondral cystlike erosions, Osteophyte formation and loose bodies (joint mice) within the joint cavity.