Preliminary results of customized bone graft made by robocasting hydroxyapatite and tricalcium phosphates for oral surgery

Abstract

The objective of this study was to assess the mechanical characteristics and the clinical usefulness of beta-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) bioblocks grafted in edentulous jaws of 12 patients. The scaffolds were produced by robocasting ceramic inks containing 80%/20% β-TCP and HA, respectively, with an overall porosity of 60%, with a macropore size between 300 and 500 μm. The mechanical performance of cylindrical vs conical specimens was compared using a universal testing machine. The clinical study was performed on 12 edentulous patients who received 4 cylindrical bone bioblocks. After 10 to 16 weeks of osseointegration, the bioblocks were explanted with trephine for histologic analysis by Goldner and Von Kossa staining. Conical shapes were significantly stronger (96.4 ± 8.7 MPa) than cylindrical shapes (87.8 ± 12.2 MPa). The overall degree of porosity ranged from 53.4% to 58.1% in the coronal region to 62.5% to 66.9% at the apex. After the maturation period, 41 valid bioblocks (85.4%) were obtained for histologic study. Bone showing some cellularity was found in 68.4% of the samples, indicating biologically active bone, and adequate calcification was found in 31.7% of the samples. In terms of biomaterial degradation, 73.2% of the samples were completely resorbed or showed significant resorption. The 80%/20% β-TCP and HA grafts customized by robocasting appear adequate for regenerating self-contained defects.