Digital titanium – Herbst appliance and psoriatic arthritis : mandibular and condylar growth effects

Introduction Temporomandibular joint (TMJ) involvement is common but usually delayed in patients with Psoriatic Arthritis (PA) To detect the early signs and manifestations of PA in temporomandibular joint by Cone Beam Computed Tomography (CBCT). The use of CBCT and 3D diagnostic protocol in young patients with PA enables reliable, accurated and precise quantitative data and images of the condylar structures and their dimensional relationships, evaluating the efficacy of therapy, too. Objectives This work shows the application of a Herbst appliance produced with CAD-CAM titanium alloy (D-Ti Herbst) in a case of PA and evaluate the growth effects on TMJ. Materials and 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 PA patient, aged 14, is investigated by CBCT and sections obtained are studied in the 3 planes of space. 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. We detect the footprints of accuracy of the dental arches and develop models in plaster. 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, a new CBCT scan to verify the results obtained, was made. Results: The Herbst is a fixed functional appliance developed. The effects skeletal 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 PA has so far shown promising results but requires a study with a larger number of patients.