In children with juvenile idiopathic arthritis (JIA) - also known as juvenile chronic arthritis (JCA), and juvenile rheumatoid arthritis (JRA) - temporomandibular joint (TMJ) involvement may lead to disturbances in mandibular function. The authors present two cases: The first is a 12-year-old male patient with JIA, including mandibular retrognathia, limitation of movements, and ankylosis, which was corrected with a combined orthodontic-surgical treatment. The second is an 81-year-old female patient with JRA, including myofascial pain, limitation of movements, and ankylosis, which was corrected surgically. The occurrence of JIA, the impact of dentofacial disturbances in JIA, and the literature are discussed in this article. Keywords: ankylosis, case report, juvenile idiopathic arthritis, orthognathic surgery, temporomandibular joint