Analysis of additive manufacturing techniques used for maxillofacial corrective surgeries

Abstract

Patients with jaw deformities often lead a poor quality of life due to problems encountered during speech, mastication and aesthetics, which makes maxillofacial reconstructive/corrective surgery necessary. Surgeons find difficulty in visualizing complex facial anatomy; therefore, a method of viewing a physical 3D maxillofacial model is highly beneficial. Accurately reproduced 3D models of a patient’s maxillofacial structure assist in pre-planning of a surgical procedure. AM (Additive Manufacturing) allows effective reproduction of a digital image into a physical model, replicating actual facial anatomy, thereby providing an effective solution. Among the AM techniques, PolyJet, FDM (Fused Deposition Modelling), SLA (Stereolithography) and SLS(Selective-Laser-Sintering) are being used for such applications. Comparison of these techniques is presented to determine the most efficient technique in reproducing such models for dimensional accuracy and cost. 20 models of five patients with deformed maxillofacial structures were designed using CAD (Computer-Aided Design) from STL (Standard Triangulation Language) files obtained from CT (Computerized Tomography) scans, which were manufactured using the aforementioned techniques. These models were then analysed for dimensional accuracies by identifying nine critical landmarks within the maxillofacial structures. Overall weight of the models was also evaluated for a cost-effective manufacturing solution. Dimensional measurement results of the 3D printed models indicated a relative error trend as PolyJet<SLA<SLS<FDM while material cost expenditure involved during 3D printing of these models indicated a trend as FDM<PolyJet<SLA<SLS, thereby recommending PolyJet as the most favoured AM technique for reproducing a maxillofacial structure. As a best practices guideline, incorporating AM for complex bone reconstruction procedures results in improved dimensional accuracies, reduced intraoperative time, reduced patient’s exposure to anaesthesia and ultimately an improved aesthetic outcome to the patient.