Abstract: PURPOSE : Rapid prototyping (RP) technology was employed to make high quality 3-dimensional head simulator, which was then precisely combined with a fine plaster cast of dental arch by facebow for model surgery to guide orthognathic surgery for mandibular asymmetry and evaluate the effect. METHODS : Fifteen patients with dento-maxillofacial deformities underwent spiral CT scan to collect raw data, which was inputted into rapid prototyping machine to generate 3-dimensional head-simulators. The plaster casts of dental arch were subsequently replaced with those of 3-dimensional head-simulators in the same ratio. Finally, RP-plaster cast complexes were formed for simulating osteotomy prior to surgery, in order to assess the position and volume of osteotomy, the symmetry of chin and variation of temporomandibular joint (TMJ), and surgical effect 6 months after operation. RESULTS : RP-plaster cast complexes from 15 patients were shown to be good for predicting the effect of surgery. Two cases were still found to have mental deviation and chin plasty was carried out after bilateral mandibular sagittal split osteotomy (BSSRO). The 6-month follow-up results showed the patients were satisfied with their appearance and had no complications including TMJ disorder. CONCLUSIONS : RP-plaster cast complex is valuable in precisely simulating osteotomy, contributing to understanding postoperative alteration of chin and TMJ and assessing surgical effect and possible complications.

Key words: Rapid prototyping technology, RP-plaster cast complex, Orthognathic surgery