Rapid Reconstruction of Temporomandibular Joint Using Ceramic Implants and Dental Adhesives

The temporomandibular Joint (TMJ) is a complex, sensitive and highly mobile joint that plays a vital role in this human masticatory system. TMJ disorders have affected millions over decades and artificial joint reconstruction is considered as the last option for treatment of this disorder. Most of the TMJ implants (two components: condyle and fossa) have failed and continue to fail. The failure may be due to inherent design flaws and use of screws for fixation. The hypothesis in this work is that a novel custom-made TMJ implant based on engineering principles can serve as a better design. An original offline generic patient-image in the form of MRI/CT scans was converted into 3D data and it was used to design patient-specific implant components that conform within the patient's bone anatomy. These final implant components can be manufactured by direct machining from ceramic ingots that exhibit excellent biocompatibility and strength. Since current-generation ceramic ingot machining systems accept data only from software of proprietary imaging programs, Rapid Prototyping Technology was used to manufacture temporary implants/devices to be re-imaged by that equipment and permanent implants to be fabricated. The skull-mounted glenoid fossa component and ramus-bone supported condylar shafts of the fabricated structural ceramic parts can be cemented directly to bone by means of dental adhesives and can serve as a better alternative to screw fixation. Finite Element Analysis (FEA) has been performed to validate the design and establish values for minimum dimensions for each component to withstand the biomechanical joint loads expected in replacement application and expected cohesive forces of dental adhesives at the joint interface. The overall joint reconstruction time from patient's TMJ scanning to fixation of implants can be controlled within 4 hours. This new approach can increase the life of the reconstructed joint and improve quality of life of the patient.