Influence of Internal Microarchitecture on the Shape of Individual Implants Made from Vinylidene Fluoride Copolymer by 3D Printing with High-Temperature Crystallization

Abstract

The healing potential of individual polymer implants for the reconstruction of extensive craniofacialdefects after cancer resection is largely determined by the internal architecture of the implant. The architectureof an implant during polymer crystallization could affect the structure and shape of the implant at themicro and macro levels. In this study, the relationship between the internal architecture (triply periodic minimumsurface structure (gyroid), cube, grid, and honeycomb) and shape changes of individual implants by3D printing with a vinylidene fluoride-tetrafluoroethylene copolymer after crystallization is examined at afilling density of 70%. Using the method of differential scanning calorimetry, it is established that crystallizationleads to the rearrangement of the crystalline structure of the implant into electrically active (ferroelectric)crystalline phases. Moreover, the type of internal architecture affects the change in the shape of theimplant after crystallization. The results of the computed tomography show that structures with a triply periodicminimum surface (gyroid) provide the minimal deformation of the implant during crystallization, whichmakes such structures optimal for manufacturing implants for replacing bone defects in the zygomatic-orbitalcomplex.