Ceramic Scaffolds for Bone Augmentation: Design and Characterization with SEM and Confocal Microscopy

Abstract

Bone scaffolds must fulfil numerous and sometimes contradictory characteristics: biocompatibility, bioactivity, high porosity, and appropriate mechanical strength. To tackle some of these issues, this study has several aims for the development of such scaffolds for dentistry applications: (i) to utilize appropriate materials (ceramics and sponges) and to introduce a novel, potentially performant ceramic material; (ii) to characterize the obtained scaffolds by using a range of methods; (iii) to compare and to correlate the assessment results with the scope to validate them reciprocally. There are two commercially available dental ceramics (i.e., Ceramco iC Natural Enamel (E) and Ceramco iC Natural Dentine (D), (DeguDent GmbH, Hanau-Wolfgang, Deutschland)) that are considered, as well as a new-developed porcelain (ceramic C). To obtain porous structures of scaffolds, each ceramic is introduced in two different sponges: a denser one, green (G) and a less dense one, blue (B). A total of 60 samples are manufactured and divided in six study groups, obtained by combining the above materials: GE, BE, GD, BD, GC, and BC (where the first letter represents the sponge type and the second one the utilized ceramic). Several methods are applied to characterize their chemical composition, as well as their macro- and micro-porosity: X-ray Diffraction (XRD), apparent porosity measurements, scanning electronic microscopy (SEM), and confocal microscopy (CM). The latter two methods image the inner (porous) and the outer/cortical (denser) areas of the samples. The results show a good porosity (i.e., dimensions and uniformity of pores) of around 65% for the final group BC, with satisfactory values of around 51% for BD and GC. A certain correlation is made between SEM, CM, and the apparent porosity results. The biocompatibility of the new ceramic C is demonstrated. Finally, a necessary trade-off is made with the mechanical strength of the obtained scaffolds, which was also evaluated. From this point of view, Group BD has the highest compressive strength of around 4 MPa, while Group BC comes second, with around 2 MPa. This trade-off between porosity and mechanical strength suggests a choice between Groups BC and BD, which are the best with regard to the porosity and mechanical strength criterium, respectively.

Utilizing machine learning and AI algorithms for inspection of airbags manufacturing processes

“…The aim of the present report is to highlight some of the issues, methods, and obtained results in utilizing both machine vision methods and AI in approaching the problem of false positive results in the quality control of the above-mentioned products. This is in line with a larger direction of work in our group in collaboration with our industrial partners, regarding product quality assessment using a range of imaging methods, including scanning electron microscopy [1], Xray imaging [2], micro-CT [3], optical coherence tomography (OCT) [4][5][6][7], and confocal microscopy [8]. Applications approached so far included metallic fractures [9,10], electronic boards [11], polymers [12], as well as dental materials of different types [13][14][15][16][17][18][19].…”

Estimation of Digital Porosity of Electrospun Veils by Image Analysis

“…Additionally, electrospinning conditions such as flow rate, voltage, temperature and injector-collector distance have to be taken into account [ 5 ]. As for the characterization of porous materials, conventional techniques like mercury intrusion porosimetry (MIP), X-ray diffraction, centrifugal porosimetry and nitrogen sorption porosimetry (NSP), among others, are based on physical methods that try to represent the totality of the sample [ 6 , 7 , 8 ]. With the use of the MIP and NSP techniques, it is very likely that the membrane be destroyed at high pressures, for the pores are not rigid enough, given the characteristics of the electrospun veils [ 9 ].…”

The Biological Activity of Fragmented Computer-Aided Design/Manufacturing Dental Materials before and after Exposure to Acidic Environment

“…Even though conventional tests are employed in the early phases of a material’s development, a postmarket information system that allows dentists to report adverse effects should be added to the biocompatibility assessment [ 1 ]. The introduction of novel materials and techniques [ 2 , 3 , 4 ], as well as the advancement of CAD/CAM (computer-aided design/computer-assisted manufacturing) technology, have significantly altered the clinical workflow in the field of dentistry, leading to new concepts for evaluation and dental treatment [ 5 ]. The CAD/CAM technique has the great advantage of reducing production time and achieving transposed and perfectly adapted structures [ 6 , 7 , 8 , 9 , 10 , 11 ].…”