Ankylosing spondylitis (AS) or Bechterew disease is a chronic, usually 
progressive, systemic inflammatory joint disease, which predominantly affects 
the spine and sacroiliac joints. In these joints, early inflammatory changes are 
followed by lumbosacral pain and progressive restriction of spinal movement 
associated with radiologically visible intervertebral ossification. Peripheral 
joint involvement occurs in 10 to 30% of patients and shows a predilection for 
the shoulders, knees, ankles, feet, and wrists. Temporomandibular joint (TMJ) 
involvement has been described, and its reported frequency varies from 11 to 
35%. However, ankylosis is uncommon with a single documented case utilizing an 
alloplastic prosthesis for total joint replacement. A case report of bilateral 
ankylosis of the jaw treated with alloplastic prostheses for total TMJ 
replacement using a Brazilian system in a patient with AS is presented.