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

Carlo Mangano,Francesco Mangano,Alessandra Giuliani,Oleg Admakin,Satoshi Iketani,Luigi Gobbi

doi:10.3390/ijms20133118

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.

Highlights

Dental implantology is a valid and predictable practice to restore function and aesthetics in partially or completely edentulous patients; implants were shown to have long survival times, in the mandible [1,2]
These bone substitute biomaterials (BSBs) are nowadays classified into four groups according to their origin: Autogenic, allogeneic, xenogenic and synthetic
Biphasic calcium phosphate (30% HA/70% β-tricalcium phosphate (TCP)) samples, produced by SLA-3D-printing or by traditionally sintered methods, were tested basing on the experimental sequence that included the following actions: MicroCT analyses of samples of each biomaterial: They served as control-references for the 3D morphometric analysis; Load tests in continuous mode, with compression up to fracture: To reconstruct the stress/deformation curve in order to study the elastic characteristics and how they change between different biomaterials; MicroCT of the same samples after the load tests: To achieve the 3D morphometric analysis for the prediction of the morphometric changes induced by compressive loading of the selected materials

Summary

Introduction

Dental implantology is a valid and predictable practice to restore function and aesthetics in partially or completely edentulous patients; implants were shown to have long survival times, in the mandible [1,2]. Several pathologic processes, including absorption of alveolar bone after tooth loss (due to a lack of mechanical loading), periodontal diseases, traumatic injuries, cysts, and tumors, often produce severe alveolar bone defects, preventing the implants to be placed correctly [5]. Several materials were used in dentistry and implantology as bone substitute biomaterials (BSBs) in order to promote and increase tissue regeneration. These BSBs are nowadays classified into four groups according to their origin: Autogenic (i.e., bone explanted from the same patient), allogeneic (i.e., bone explanted from another person), xenogenic (bone originating from animal models) and synthetic (with no biological origin)

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Discussion

Conclusion