A novel conceptual design of a biomimetic oral implant and its biomechanical effect on the repairment of a large mandibular defect

This study aimed to propose a novel biomimetic design strategy of an oral implant and to numerically examine its biomechanical effect according to clinical interests. The designed implant conceptually mimicked the morphology and elastic modulus of the mandibular bone. Basing on a CT-image-based patient-specific reconstruction of the tumor-excised mandible, the biomechanical effects of the implants with three materials (PEEK/n-HA/CF, PEEK/HA and Ti6Al4V), two surgical conditions (removed and retained muscles), and two postoperative stages (early and late) were fully investigated by a static finite element analysis. Moreover, according to clinical interests (e.g. failure and stability of the implant and rivets), maximum von Mises stresses and strains of the implant and rivets, maximum implant-bone gap in the early postoperative stage, and maximum von Mises stress of the mandible were mainly analyzed. The results showed that the implant composed of Ti6Al4V material was suitable for the current design strategy with respect to the other two PEEK-based materials. Although the implants in the muscle-retained surgical condition had relative greater indices compared to the muscle-removed surgical condition, the index difference between the two conditions was slight. The biomechanical indices indicating the failure and loosening risks of implant and rivets were much reduced in the late postoperative stage with respect to the early postoperative stage due to the osteointegration at the implant-bone interface. Generally, the proposed novel design strategy could be useful to guide the design of the oral implant addressing different implant materials and surgical conditions, and further made proper suggestion to clinicians and patients.