Dimensional variations of the mandibular triangle in orthodontic patients affected by Juvenile Idiopathic Arthritis

Background: To highlight the dimensional variations of the mandibular triangle of the healthy patients versus patients with Juvenile Idiopathic Arthritis (JIA) by means of Cone Beam CT (CBCT). Methods: 75 CBCTS, 36 of healthy patients and 39 of patients with JIA, aged between 6 and 15 years, were analyzed. The study was based on the identification of the right Gonion cephalometric point (Go dx), left Gonion (Go Sx) and Menton (Me) through a 3D Medical Image Processing Software, thus obtaining the mandibular triangle. Results: From the observation of the collected values, it is showed that the Gonial angle corresponding to the healthy side undergoes a reduction of the amplitude. Contrariwise, the Gonial angle corresponding to the side affected by the disease, undergoes an increase of its amplitude. The proportionality of these values is strongly influenced by the age in which the patient has been evaluated, considering that the sample is composed of patients ranging from 6 to 15 years, younger the patient is, less would be the difference evident and significant between the lengths of the sides and relative angles, at time 0 and at time 1. Conclusions: The results show that patients suffering from JIA have a reduction in the sagittal growth of the jaw, corresponding to the side affected by the disease; this implies a proportional increase of the angle associated with it. On the other hand, the growth of the healthy side appears to be normal and physiologically active as it is not affected by the disease. The final result is the presence of a pronounced asymmetry of the mandibular bone of the patients with Juvenile Idiopathic Arthritis (JIA).