An innovative total temporomandibular joint prosthesis with customized design and 3D printing additive fabrication: a prospective clinical study

Abstract

Background: Total temporomandibular joint (TMJ) prosthesis is an effective and reliable method of joint reconstruction. However, there is still an urgent need to design a new TMJ prosthesis because of no commercially available TMJ prosthesis appropriate for the clinical application on the Chinese population. This study was introduced to prospectively confirm the safety and effectiveness of a new TMJ prosthesis with customized design and 3D printing additive fabrication in clinical application.

Methods: Patients with unilateral end-stage TMJ osteoarthrosis were recruited in this study from Nov 2016 to Mar 2017. Computed tomography scans for all patients were obtained and transformed into three-dimensional (3D) reconstruction models. The customized TMJ prosthesis consisted of three components including the fossa, condylar head, and mandibular handle units, which were designed based on the anatomy of the TMJ and were fabricated using the 3D printing technology. The prominent characters of the prosthesis were the customized design of the fossa component with a single ultra-high-molecular-weight polyethylene and the connection mechanism between the condylar head (Co-Cr-Mo alloy) and mandibular handle components (Ti6Al4 V alloy). The clinical follow-up, radiographic evaluation and laboratory indices were all done to analyze the prosthesis' outcomes in the clinical application.

Results: 12 consecutive patients were included in the study. There were no complications (infection of the surgical wound, damage of liver and kidney, displacement, breakage, or loosening of the prosthesis) found after surgery. Pain, diet, mandibular function, and maximal interincisal opening showed significant improvements after surgery. But the lateral movement was limited to the non-operated side and the mandible deviated towards the operated side on opening mouth following surgery.

Conclusions: The presented TMJ prosthesis is considered an innovative product in TMJ Yang's system, which is unique compared to other prostheses for the special design and 3D printing additive manufacture. Moreover, the prosthesis is very safe and efficient for clinical use. Trial registration Prospective reports on Chinese customized total temporomandibular joint prosthesis reconstruction cases, ChiCTR-ONC-16009712. Registered 22 Nov 2016, http://www.chictr.org.cn/showproj.aspx?proj=16091.

Keywords: 3D printing; Clinical application; Customized prosthesis; Temporomandibular joint.

Fig. 1

The comparison between the new prosthesis and the Zimmer Biomet or TMJ concepts products. a The Zimmer Biomet prosthesis. b The TMJ concepts prosthesis. c The TMJ prosthesis in this study

Fig. 2

The processing of the new TMJ prosthesis, including the pre-processing for the craniomaxillofacial model, the design for the prosthesis, and the manufacture for the prosthesis. The main innovative points of the prosthesis are the customized fossa component with single UHMWP and the Machine tape mechanism for the connection between the condylar head (Co–Cr–Mo alloy) and mandibular handle components (Ti6Al4 V alloy)

Fig. 3

The surgical procedure for the new TMJ prosthesis. a, b The resection of the entire condyle and the lower part of the articular eminence by using the surgical templates. c The fixation of the fossa component with the guide of the holes in the template. d, e The fixation of the mandibular handle component with the help of the endoscope and transbuccal retractor. f The graft of free fat harvested from the buccal fat pad to fill into the space around the prosthesis neck

Fig. 4

Subjective assessment outcomes over time. a Pain. b Diet. c Mandibular function

Fig. 5

Objective assessment outcomes over time. a Maximal interincisal opening (MIO). b Mouth opening deviation (MOD). c Lateral movement to diseased side (MDS). d Lateral movement to normal side (MNS). e Mandible forward movement (MFM)