ABSTRACT. Introduction: Functional disorders of the stomatognathic system are included among temporomandibular disorders (TMDs). There are many etiological factors which can be of different importance for certain patients. Temporomandibular joint (TMJ) disorders include the anterior disc displacement (DD) and/or articular osteoarthritis. The prevalence of displaced TMJ disc in childhood and adolescence is low. The most frequent symptoms are clinically slightly expressed. Case report: Here, we describe the case of a 12-year-old girl with TMD. The patient reported clinical signs and symptoms (clicking) in TMJs bilaterally and has been referred by the orthodontist because she needed treatment of the cross-bite. The magnetic resonance imaging of the left TMJ showed DD without reduction and DD with reduction in the right TMJ. Painless clicking in the TMJ is an insufficient clinical finding which would require treatment of TMD. Conslusions: Clicking is the result of articular disc repositioning on mouth opening and its return into the displaced position on mouth closing. So far, there has been only a description of a large number of risk factors and no evidence of the correlation between causal factors. Therefore, for patients’ benefit, it is necessary to determine appropriate diagnostic and therapeutic procedures in order to improve the function of the masticatory system. The cross-bite was not an occlusal anomaly associated with TMD, but the orthodontic treatment as a form of definitive rehabilitation of occlusion has to be carried out very carefully.