European Journal of Orthodontics 30 (2008) 545–551
© The Author 2008. Published by Oxford University Press on behalf of the European Orthodontic Society.
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Juvenile idiopathic arthritis (JIA) relates to a heterogeneous
group of diseases of unknown aetiology, characterized by
chronic infl ammation of one or more joints, with an onset
before the age of 16 years and a minimum duration of
6 weeks ( Petty et al. , 2004 ). JIA is considered to be an
autoimmune disorder with a complex genetic component.
The prevalence is reported as 0.07 – 4.01 per 1000 children,
while the annual incidence of JIA is 0.008 – 0.226 per 1000
children ( Manners and Bower, 2002 ).
Involvement of the temporomandibular joint (TMJ) was
recognized by Still (1897) . The reported prevalence has
ranged from 17 to 87 per cent based on the JIA subtype, the
methods used for diagnosis, and the population studied
( Larheim et al. , 1981 ; Ronchezel et al. , 1995 ; Pedersen
et al. , 2001 ; Twilt et al. , 2006 ; Billiau et al. , 2007 ). The TMJ
can be affected unilaterally or bilaterally, early or late in the
course of the disease, and can even be the fi rst joint affected
( Twilt et al. , 2006 ). Regarding chronic infl ammation of the
joints, erosive disease may develop with destruction of
the joint cartilage and the subchondral bone and affect the
adjacent growth cartilage, which in turn may lead to local
growth disturbances and long-term disability ( Sidiropoulou-
Chatzigianni et al. , 2001 ). The TMJ is particularly vulnerable
to dysplasia because the centre of growth of the mandible is
located below the articular surface of the condylar head
instead of more distal to the joint ( Twilt et al. , 2003 ).
Regarding TMJ arthritis, erosion and fl attening of the
Condylar asymmetry in children with juvenile idiopathic arthritis
assessed by cone-beam computed tomography