Optimized 3D virtually planned intermediate splints for bimaxillary orthognathic surgery: A clinical validation study in 20 patients

Orthognathic surgery is indicated for the treatment of significant skeletal malocclusions and facial dysmorphosis. Recent technological developments allow surgeons to virtually plan the orthognathic jaw movements. When producing intermediate splints, overlap between the upper and lower dentitions can occur. Autorotation of the mandible is often used as a solution for this problem. The purpose of this study was to present an optimized approach to fabricate digital intermediate splints based on the use of a scanned thick wax bite to overcome dental overlap during planning. Twenty patients (9 males and 11 females) undergoing bimaxillary orthognathic surgery participated in this prospective study. Planning of the maxillary movements was conducted by the same surgeon. The thick wax bite was scanned using an intraoral scanner and a special CBCT protocol. The fabrication of the intermediate splints was done by means of conventional model surgery and virtual 3D planning-printing. The splints were clinically assessed by comparing the digitally printed intermediate splints to the corresponding conventional set-up which served as the clinical standard. Moreover, reproducibility and comparison tests between the scanned wax bites were implemented. The root mean square (RMS) for the reproducibility and comparison tests was respectively 0,15 mm (SD 0,24 mm) and 0,19 mm (SD 0,08 mm). 19 out of the 20 intermediate digitally 3D printed splints were clinically accepted. This proposed protocol can be considered as an optimization to the current 3D planning protocols of bimaxillary orthognathic surgery.