GAP Australasian Dentist Mar Apr 2020

Category 76 Austràlàsiàn Dentist Maxillary reconstruction using 3Dàprint technology INTRODUCTION àhe ideal aims of jaw reconstruction following ablative tumour surgery are to restore form and function with minimal patient morbidity (1). Current reconstructive techniques have made little progress over the last 3 decades as we are still dependent on microvascular composite bone flaps and conventional dental implants that involve protracted treatment timelines often with less than ideal outcomes for the patient. àhe aim of this article is to present a truly 21st century solution for a complex maxillectomy case that had initially fallenway short of patient expectations following conventional bone reconstruction using the patients leg bone (fibula). CASE REPORT A 31yo female presented to the author with a severe midface deformity that made it impossible for her to venture into public areas without attracting negative attention (Fig. 1). A year before her initial presentation she had a bilateral subtotal maxillectomy to treat an osteosarcoma of the maxilla which was done via a transoral approach. àhe defect was immediately reconstructed with a straight strut of vascularized fibula bone that completely failed to restore the missing maxillary arch (Fig. 2). àhis made the subsequent placement of dental implants impossible (2). Hence, the patient was left with a severe speech impediment, inability to chew and a facial disfigurement that prevented her from venturing out into public areas without a facemask (Fig.1). àsing DàCOMCà scans of her existing skeletal deformity, the author, together with a team of Biomedical engineers at OMX àolutions, designed a titanium frame (using Materialize software – Belgium) that not only reproduced the missing maxillary arch, but also had three internal abutments onto which prosthetic teeth would be subsequently attached by direct screw fixation (Fig. 3). A specialist prosthodontist was consulted to determine the precise placement of the maxillary teeth which dictated the final dimensions and positioning of the titanium frame and the spread of the dental abutments. àn August 2018, the patient underwent secondary reconstruction whereby her upper lip was surgically released from its base and the 3D printed custom titanium frame was inserted (fig. 4). àhe frame itself was attached to the fibula and remaining zygomatic buttresses with three customized baseplates and bone screws so it was an accurate fit which negated the need for bone preparation. Crushed autogenous bone was then placed into the space between the fibula strut and titanium arch and the defect was covered with a vascularized radial forearm flap to cover the implant and restore the missing soft tissues of the anterior palate. àhree months later, the radial forearm flap was debulked and transmucosal abutments were attached to the titanium frame upon which a bridge of prosthetic teeth stretching from second premolar to second premolar were firmly fixed onto the three abutments with internal screws (Fig. 5). àhis not only immediately restored the patient’s normal upper lip projection and contour, but also gave her back the ability to chew and speak clearly. àhe was last followed up a year later with a smile and confidence that basically demonstrated she was back to living a normal life (Fig. àlàn al By Dr George Dimitroulis Dr George Dimitroulis Figure 1: Initial presentation of the patient described in this article showing severe upper lip deficiency following bilateral maxillectomy for maxillary osteosarcoma Figure 2: CT scan of the maxillary defect showing the straight strut of fibula (leg) bone fixed to the zygomatic buttresses with bone plates and screws, making it impossible to place dental implants to support an arch of prosthetic teeth that would match her mandibular arch of teeth. Figure 3: Design of the titanium frame (depicted in green) attached to the existing bony maxillary deformity which supports an arch of virtual prosthetic maxillary teeth (depicted in purple).