Psoriatic arthritis : temporomandibular joint involvement as the first articular phenomenon

Aim: The aim is to underline the importance of the paediatric dentist and orthodontist in the contribution to the early diagnosis of Psoriatic Arthritis, avoiding and preventing the orofacial and systemic complications. Materials and Methods: Psoriatic Arthritis (PA) is a chronic systemic disease that is difficult to detect. The diagnosis is made mainly on clinical grounds based on the findings of psoriasis and inflammatory arthritis of the joints. Many reports have described the damaging effects of PA on the temporomandibular joints (TMJs), but no study has clearly reported the TMJ as the first articulation to be involved in PA. This work reports a case of PA that was diagnosed several years after a TMJ onset because no other signs apart from psoriasis were present. Results: The missed early diagnosis resulted in severe TMJ damage. The TMJ can be the first joint involved in PA. It is often unilateral, with a sudden onset. Symptoms include pain and tenderness of the joint area and the muscles of mastication, morning stiffness, tiredness in the jaws, joint crepitation, occasional painful swelling of the TMJ capsule and painful mandibular movements associated with a progressive decrease in the interincisal opening. In severe cases, ankylosis of the TMJ may occur. Discussion: Because the symptoms of TMJ involvement are generally nonspecific, the diagnosis of PA of the TMJ is difficult and is made mainly on the basis of the systemic presentation of the disease. In general, the diagnosis is based on a triad of psoriasis, radiographic evidence of erosive polyarthritis, and a negative serologic test for RF. However, even in the presence of a skin rash, the diagnosis of PA cannot be absolutely confirmed. The differential diagnosis of PA should always include entities such as RA, Reiter syndrome, AS, and gout. Radiographic changes associated with PA may be seen in as many as 82% of the patients with affected TMJs and include erosion, flattening, osteoporosis, loss of joint mobility, and extreme joint space narrowing. Subchondral bone cysts, subluxation, and ankylosis are also occasionally observed. The radiographic changes are nonspecific and cannot be easily distinguished from those of other types of arthritis, particularly RA and AS. Conclusions: For a correct, early diagnosis of PA, collaboration between the dentist and rheumatologist it is very important. The dentist should recommend in addition to exercise and local pain treatment, an occlusal splint to help keep the TMJs working properly, improve function, relieve pain, reduce swelling, and prevent further severe TMJ damage.