Prevalence and incidence of radiographic imaging abnormalities , symptoms , and physical exam findings Initial estimates of the prevalence of TMJ involvement in

Recent recognition of the markedly high prevalence of temporomandibular joint (TMJ) arthritis in children with juvenile idiopathic arthritis (JIA) coupled with the significant morbidity associated with TMJ damage has prompted increased interest in both the clinical and pathological aspects of TMJ arthritis. This review focuses on the prevalence of TMJ arthritis in JIA, the imaging modalities used to detect TMJ arthritis, and the treatment of TMJ arthritis in children with JIA. Background TMJ arthritis in children with chronic arthritis was first reported by Still in his initial case series in 1897 [1]. Although TMJ arthritis in JIA is frequently asymptomatic, the TMJ is particularly susceptible to damage from arthritis due to its unique anatomy and biochemical composition. Unlike other synovial joints, the mandibular growth plate lies under a thin layer of fibrocartilage located at the surface of the condylar head [2]. Mandibular growth occurs within this center from the prenatal period until just after puberty, and damage to the growth center due to inflammation or trauma during this time period frequently results in alterations in mandibular growth [3]. In JIA, this damage has been associated with a number of clinically significant outcomes, including decreased chewing ability, malocclusion, and micrognathia. These outcomes are not infrequent, and prior studies have reported micrognathia in approximately 30% of children with JIA and malocclusion in approximately 66% [4,5]. Furthermore, even apparently minor radiographic changes have been associated with disrupted mandibular growth and a number of significant craniofacial changes [6]. Children with JIA also have a higher prevalence of headache, neck pain, and jaw dysfunction than healthy controls, both at the time of diagnosis of their TMJ disease and at long-term follow-up [7,8]. A recent prospective cohort study of children with JIA and healthy controls which reported data on patients and controls at baseline and after 15 years of follow-up found that, although there were no difference in TMJ-related symptoms at baseline, after 15 years children with JIA reported a statistically significant higher prevalence of tiredness of the jaw (46%, p = 0.04), pain in face or jaw (39%; p = 0.02), and difficulty in opening their mouth wide (36%; p = 0.02). In addition, these children had an increased prevalence of additional symptoms that may be associated with TMJ disease, including tooth clenching, headache, neck pain, shoulder pain, and impaired general health at follow-up [7]. These findings, coupled with the fact that the TMJ is one the most frequently used synovial joints in the body, used up to 2,000 times per day for chewing and speaking, highlight the importance of recognizing and treating TMJ arthritis during childhood. Published: 29 May 2009 Pediatric Rheumatology 2009, 7:11 doi:10.1186/1546-0096-7-11 Received: 17 March 2009 Accepted: 29 May 2009 This article is available from: http://www.ped-rheum.com/content/7/1/11 © 2009 Ringold and Cron; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.