German researchers develop first customised mandibular implant
DRESDEN, Germany: Engineering researchers and members of an interdisciplinary research group have developed the world’s first complex method for producing an individualised mandibular implant. The first patient to receive the newly developed implant was successfully treated at the Department of Oral and Maxillofacial Surgery at the Dresden University Hospital, Germany.
Previously, bone defects in the oral and maxillofacial region were treated with ready-made reconstruction plates. This led to functional and aesthetic complications within a short period in about 45 per cent of cases. As the standard plates could not be fitted precisely to the remaining bone, the overlying mucosa was exposed to heavy forces after surgery. This often caused inflammation and loosening of the plates. In addition, it led to the breaking of the reconstruction plate because the implant and the bone had different strengths. The consequences were extensive functional and aesthetic deficits.
A research team of engineers at the Faculty of Mechanical Engineering at the Dresden University of Technology (TU Dresden), doctors at the Carl Gustav Carus University Hospital at TU Dresden (Department of Oral and Maxillofacial Surgery), doctors at the clinic of Dental Prosthetics, and engineers at the company Hofmann & Engel has now managed to develop a customised mandibular implant made of titanium.
“As the new jaw implant has the same strength and geometry as the adjacent bone, the material no longer breaks at the junctions, which prevents aesthetic deficits after surgery and further medical intervention. In addition, attachment to the remaining parts of the jaw conserves tissue. This ensures optimal healing,” said Ralph Stelzer, Professor of Construction Technology/CAD at the Faculty of Mechanical Engineering.
In order to ensure biocompatibility, the interdisciplinary research team used pure titanium. During a complex manufacturing process, the metal is melted and then built up in layers. The outer shell of the implant corresponds to a wall thickness of only 0.3 mm, which equals the strength of the removed jawbone. To prevent the titanium implant from being too heavy and temperature sensitive, it is fabricated as a shell structure. The researchers are currently working on a method to fill the interior of the implant with a filigree structure that stimulates bone growth.
As a starting point for the construction of the implant, the researchers used CT data from a diseased patient. The individual data processing is carried out as a virtual 3-D model using software that was developed especially for this purpose by a working group at TU Dresden. Based on the digital model, the mandibular implant is individually designed, adapted and then manufactured at Hoffmann & Engel. “The difficulty was integrating the IT of the various disciplines and the logistics, from medical diagnosis, design and manufacture, to surgical planning and patient care. This interdisciplinary collaboration allows for the first time the production of a customised implant for a patient in about 32 hours,” said Dr Christine Schöne, leader of the engineering part of the project. The software solution, which was developed as part of the project, is currently being adapted to solve other problems concerning surgical planning, such as those that arise when placing dental implants.