CATEGORY 76 AUSTRALASIAN DENTIST CLINICAL Introduction: As we move well into the 21st century, the surgical landscape is rapidly changing from off-the-shelf solutions to patient specific design and manufacture of medical devices. Digital technology has permeated all aspects of our lives and the field of medical devices is no exception to the incredible progress that has been made in the last decade or so. The Tri-Fix Orthognathic system is a digital platform that was developed in Australia by local surgeons and biomedical engineers who envisaged a streamline process of planning, designing, and manufacturing patient specific solutions for the field of corrective jaw surgery. While the system is not unique, it does exemplify the local talent and capabilities of Australian know how that compares well to the much larger North American and European medical device companies. The aim of this article is to highlight the advantages of the TriFix Orthognathic System in the surgical correction of jaw deformities. Case example: A 22yo female presented to the author with a class 2 dentofacial deformity and an anterior open bite (Figs. 1 – 3). After 12 months of presurgical orthodontics, she had a CT scan of her jaws and intra-oral scan of her dentition. The Orthodontist also sent in a digital scan of the final desired occlusal relationship he wanted from the surgery. Working from the scans, the biomedical engineers in collaboration with the author set out the osteotomy lines and undertook the virtual corrective two jaw surgery movements to establish the final occlusal position as prescribed by the Orthodontist. Cutting and drilling guides (Figs. 4, 5) for the LeFort 1 osteotomy of the maxilla as well as patient-specific titanium maxillary bone plates were designed, together with mandibular sagittal split cutting guides that were sent off for 3D printing after they were approved by the author. At the time of surgery, the maxillary cutting and drilling guide (Figs. 6, 7) was used to undertake the LeFort 1 osteotomy and the custom bone plates were used to accurately position the freed-up maxilla to the fixed facial bones by lining up the pre-drilled screw holes (Figs. 8 – 11). This meant an intermediate surgical occlusal wafer was not required for the maxillary positioning. Using patient specific cutting guides for the mandibular osteotomy (Fig. 12), accurate cuts were made of the medial ramus that extended precisely to the lingula of the mandibular foramen. The vertical body osteotomies were also facilitated by the same sagittal split cutting guides. Conventional bone plates were used after the sagittal split was successfully executed. Similar cutting/drilling guides with patient specific plates can also be used for a genioplasty which was not required in this case. Discussion: The Tri-Fix Orthognathic System not only provides an orthognathic planning service, but also supplies patient specific cutting THE TRI-FIX™ ORTHOGNATHIC SYSTEM: An Australian Digital Solution for Corrective Jaw Surgery By George Dimitroulis, Oral & Maxillofacial Surgeon, Epworth-Freemasons Hospital Melbourne Figure 1: Preoperative view of the patient’s profile. Figure 3: Patient’s occlusion on her initial presentation with a Class 2 anterior open bite. Figure 2: Preoperative Lateral Cephalogram of patient prior to commencement of pre-surgical orthodontics. Figure 4: Computer image of the patient’s facial skeleton showing the custom cutting and drilling guide in grey. Figure 5: Biomodel of the patient’s midface showing the accurate positioning of the 3D printed titanium custom cutting and drilling guide. Figure 6: Intra-operative view of the custom titanium cutting and drilling guide positioned on the maxilla.
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