Herbst appliance in juvenile idiopathic arthritis patients: mandibular and condylar growth effects

Aim: This work shows the application of a Herbst appliance produced with CAD-CAM titanium alloy (D-Ti Herbst) in a case of Juvenile Idiopathic Arthritis (JIA) and evaluate the growth effects on TMJ. Methods: The use of CAD-CAM is growing exponentially in dentistry, since its introduction in the field of prosthetics in the 80s. It also finds application in the orthodontic field, it can be produced with this technology palatal expanders, Michigan plates, guide masks for presurgical orthodontics. The JIA patient, aged 14, is investigated by Cone Beam CT (CBCT).The left TMJ has a marked erosion of a round shape in the central portion of the head of the condyle. And there is slight lateral deviation during opening movement with Class II malocclusion and deep bite. Herbst equipment has applied to bring the jaw forward. The models are scanned with scanners and structured light so you get the digital models. Using CAD software is designed the structure of the apparatus, which is then produced with the use of a numerically controlled milling machine. The Herbst is made and cemented, tried in the mouth with a cement-based resin. After removal of the equipment, 1 year later, you run a new CBCT scan to verify the results obtained. Results: The Herbst is a fixed functional appliance developed. The skeletal effects arising from the application of this apparatus is mostly during the peak of growth: in particular at the level of the jaw one can obtain a growth beyond the 3mm for the dislocation of the condyle in the glenoid fossa and stimulation of new bone apposition especially in the portion top and back of the condyle. The analysis shows that the new CT at the level of the condyle there was bone remodeling and neoformation that has bridged the gap between right and left condyle erosion caused this previously. Conclusions: The CAD / CAM applied to the materials from the aerospace industry such as titanium grade 5 make the design and implementation of the D-Ti Herbst simpler than traditional Herbst. The application in patients with JIA has so far shown promising results but requires a study with a larger number of patients.