PLA-based ceramic composites for 3D printing of anthropomorphic simulators

Additive manufacturing has become increasingly useful for the development of biomedical devices. Particularly, medical and dental studies have benefited from anthropomorphic simulators (phantoms) that can be 3D-printed using materials with radiopaque properties similar to human tissues. Among the various 3D printing techniques, material extrusion has gained significant attention due to its simplicity and cost-effectiveness. This study aimed to develop PLA (polylactic acid) composite filaments by incorporating natural hydroxyapatite, aluminum oxide, and zirconium oxide. These composites underwent thermal, morphological, and mechanical characterization, and their intensity in computed tomography was compared with that of human tissues. The zirconium oxide composites exhibited a maximum value of 184 Hounsfield Unit (HU), closely mimicking cortical bone, with a mere 6% weight fraction of ZrO2. Conversely, natural hydroxyapatite and aluminum oxide did not demonstrate any significant improvements over pure polymers for soft tissue applications. The influence of porosity on printed components was observed to decrease mechanical properties and X-ray intensity. The use of stearic acid as a surfactant helped to improve the distribution of ceramic powder within the polymer matrix. This resulted in better fluidity of the composites, facilitating successful 3D printing using the filament extrusion process. Overall, the results suggest that the newly developed PLA-based zirconia composite filament can be utilized to mimic cortical bone in anthropomorphic simulators for use in medical and dental studies.