Comparative Study between Laser Light Stereo-Lithography 3D-Printed and Traditionally Sintered Biphasic Calcium Phosphate Scaffolds by an Integrated Morphological, Morphometric and Mechanical Analysis

Abstract

In dental districts, successful bone regeneration using biphasic calcium phosphate materials was recently explored. The present study aimed to perform a comparative study between 3D-printed scaffolds produced by laser light stereo-lithography (SLA) and traditionally sintered biphasic calcium phosphate scaffolds by an integrated morphological, morphometric and mechanical analysis. Methods: Biphasic calcium phosphate (30% HA/70% β-TCP) samples, produced by SLA-3D-printing or by traditional sintering methods, were tested. The experimental sequence included: (1) Microtomography (microCT) analyses, to serve as control-references for the 3D morphometric analysis; (2) loading tests in continuous mode, with compression up to fracture, to reconstruct their mechanical characteristics; and (3) microCT of the same samples after the loading tests, for the prediction of the morphometric changes induced by compressive loading of the selected materials. All the biomaterials were also studied by complementary scanning electron microscopy to evaluate fracture regions and surfaces. Results: The characterization of the 3D mineralized microarchitecture showed that the SLA-3D-printed biomaterials offer performances comparable to and in some cases better than the traditionally sintered ones, with higher mean thickness of struts and pores. Interestingly, the SLA-3D-printed samples had a higher ultimate strength than the sintered ones, with a smaller plastic region. Moreover, by SEM observation, it was observed that fractures in the SLA-3D-printed samples were localized in the structure nodes or on the external shells of the rods, while all the traditionally sintered samples revealed a ductile fracture surface. Conclusions: The reduction of the region of plastic deformation in the SLA-3D-printed samples with respect to traditionally sintered biomaterials is expected to positively influence, in vivo, the cell adhesion. Both microCT and SEM imaging revealed that the studied biomaterials exhibit a structure more similar to human jaw than the sintered biomaterials.

Case Report: Histological and Histomorphometrical Results of a 3-D Printed Biphasic Calcium Phosphate Ceramic 7 Years After Insertion in a Human Maxillary Alveolar Ridge

“…Finally, the surgeon can easily adapt the customized scaffold in the surgical site, performing a straightforward and less time consuming surgery procedure, with reduced discomfort for the patient (Figliuzzi et al, 2013;Mangano et al, 2015b;Luongo et al, 2016;Kim et al, 2020). Micro-and macro-porous biphasic calcium phosphate (BCP) have been mainly recommended and characterized in oral surgery practices (Piattelli et al, 1996b;Mangano et al, 2013aMangano et al, , 2015bMangano et al, , 2019Giuliani et al, 2014Giuliani et al, , 2016Kim et al, 2020). They are produced by combining HA and beta-TCP in various compositions rates (HA/beta-TCP ratios), and represent the most important BCP ceramics for dental and medical applications (Piattelli et al, 1996b;Mangano et al, 2013aMangano et al, , 2015bMangano et al, , 2019.…”

Integrated 3D Information for Custom-Made Bone Grafts: Focus on Biphasic Calcium Phosphate Bone Substitute Biomaterials

“…The recent literature widely reports successful bone regeneration using biphasic calcium phosphate scaffolds, with special reference to dental districts [ 30 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. However, just a single study of ours described an integrated morphological, morphometric, and mechanical 3D analysis on these biomaterials [ 30 ].…”

“…Several physical forces and moments act daily on the jawbone during speaking or eating. In particular, during mastication, the jaw is subjected to compressive stress that is in non-linear relation with the strain [ 30 ] because of the yielding caused by debonding of osteons at cement lines and microfractures [ 49 ]. Compressive strengths of cancellous bone were found in the range of 2–12 MPa [ 50 , 51 ], depending on the skeletal site; thus, developing constructs as scaffolds with mechanical strength similar to the hosting bone is of paramount importance.…”

“…In this context, several computer-aided imaging techniques were used to investigate the microarchitecture of BSBs; in particular, the gold standard for a reliable 3D examination is based on high-resolution X-ray computed tomography (microCT). MicroCT was not only successfully used to reconstruct the morphometry of bone tissue at different length-scales [ 20 , 21 , 22 , 23 , 24 ] and in different environmental and genetic contexts [ 25 , 26 , 27 , 28 ], but it is nowadays the elective technique for the characterization of biomaterials used in bone tissue engineering [ 29 ] and also in dental districts [ 30 , 31 , 32 , 33 , 34 , 35 ].…”

“…We recently performed a first successful microCT test, combining morphometric 3D analysis with a new protocol of study referred to as BCP’s mechanical properties [ 30 ]; in the present study, BCP were studied again during compressive tests up to fracture, testing, for the first time to the authors’ knowledge, inferences and correlations between 3D microstructure, mechanical properties, sintering temperature, and time at peak temperature. The objective was the monitoring of β-Ca 3 (PO 4 ) 2 to α-Ca 3 (PO 4 ) 2 transition, finding the best processing conditions for biphasic calcium phosphate biocomposites.…”