GAP Australasian-Dentist-Mar Apr 2019

Category AustrAlAsiAn Dentist 95 scans were uploaded to the OMX solutions website (www.omx-solutions.com) with a request for a right tMJ custom prosthesis. Within 48hrs, OMX engineers contacted the author via e-mail which contained a link where a 3D dynamic image of the newly designed custom tMJ prosthesis of the patient could be viewed by the author/ surgeon (fig. 3). the size and positioning of the new prosthesis was checked by the author and, as no further changes were required, a reply e-mail to OMX engineers was sent to give them the green light to proceed with manufacture of the custom tMJ prosthesis. the new custom tMJ prosthesis was delivered to the Hospital within 3 weeks of the initial order (fig. 4). the patient underwent right tMJ surgery where the degenerate disc and condylar head were surgically removed and the right tMJ replaced with a customized polyethylene fossa secured with titanium screws to the base of skull, and a customized titanium ramus/condyle which was secured with titanium screws to the ramus of the mandible (fig. 5). the patient’s occlusion was preserved with the aid of a surgical splint and guide and the intermaxillary wire fixation was completely removed at the end of the surgery (fig. 6). the patient remained in hospital for 3 nights and sutures were removed 1 week later. she remained on a soft diet for 4 weeks and thereafter gradually returned to normal diet and oral function with the help of specialist jaw physiotherapy. the pain in the right tMJ had resolved after 3 months and she only took Panadol for headaches and the occasional jaw muscle pain. On her 2 year review, the scars were almost invisible (fig. 7) and she maintained an excellent interincisal opening of 41mm (fig. 8) and was enjoying a normal dietary range of food that was impossible prior to her surgery. CASE 2 A 53yo male was referred to the author for surgical management of posttraumatic osteoarthritis which resulted in ankylosis (fusion) of both tMJ’s to the base of skull (fig. 9). the patient was involved in a serious motor vehicle accident about 20 years ago, from which he sustained multiple injuries including bilateral condylar fractures of his mandible. Multiple surgical attempts to repair the shattered mandibular condyles resulted in eventual fusion of the tMJ’s which significantly reduced his inter-incisal oral opening to 8mm (fig. 10). Because of the complex nature of his injuries, the patient was sent to the author for further surgical management. As with most tMJ ankylosis patients, pain was not an issue. the biggest concern lInICal Figure 1 – Part of an OPG x-ray showing flattening of the right condyle indicative of TMJ degenerative joint disease (ie. Osteoarthritis) Figure 3 – Virtual image of 3D reconstructed CT scans of the patient showing a transparent mandible and correct placement of the OMX TMJ prosthetic total Joint prosthesis system which is used to design, plan and manufacture the customized TMJ implant for each patient. The course of the ID nerve along the mandible is shown in pink which determines the safe position of the screws. Figure 2 – Coronal CT scan showing subchondral cysts in the right mandibular condyle (left side of image) which is diagnostic of TMJ osteoarthritis Figure 5 – OPG x-ray showing the implanted TMJ prosthesis on the left (ie. her right condyle) secured with titanium alloy screws. The plastic fossa is invisible but the screws can be seen along the skull base. Figure 4 – A 3D printed Nylon skull of the actual patient based on her CT scans and the OMX customized TMJ total joint replacement system which is designed to closely fit her jaw. Note the polyethylene fossa (cup) attached to her base of skull and the titanium condyle (ball) attached to her mandibular ramus. Figure 6 – Lateral Cephalogram x-ray showing the position of the TMJ prosthesis at the posterior border of the mandible. Figure 7 – Two years after her surgery, the patient’s scars in the neck and in front of the ear are almost invisible. Figure 8 – The patient demonstrating excellent mouth opening 2 years following her right TMJ prosthetic total joint replacement surgery.