Towards improved functionality of mandibular reconstruction plates enabled by additively manufactured triply periodic minimal surface structures

Abstract

Additive manufacturing for fabrication of patient-specific oral and maxillofacial implants enables optimal fitting, significantly reducing surgery time and subsequent costs. However, it is still common to encounter hardware- or biological-related complications, specifically when radiation treatment is involved. For mandibular reconstruction plates, irradiated patients often experience plate loosening and subsequent plate exposure due to a decrease in the vascularity of the irradiated tissues. We hypothesize that an acceleration of the bone ingrowth prior to radiation treatment can increase the survival of such plates. In this work, a new design of a mandibular reconstruction plate is proposed to promote osseointegration, while providing the necessary mechanical support during healing. In this regard, six different Triply Periodic Minimal Surface (TPMS) structures were manufactured using laser-powder bed fusion. Three-point bending and in-vitro cell viability tests were performed. Mechanical testing demonstrated the ability for all structures to safely withstand documented biting forces, with favorable applicability for the Gyroid structure due its lower flexural modulus. Finally, cell viability tests confirmed high cell proliferation rate and good cell adhesion to the surface for all TPMS structures. Overall, the new design concept shows potential as a viable option for plates with improved functionality and higher survival rate.