Biomimetic customized composite scaffolds and translational models for the bone regenerative medicine using CAD-CAM technology

Nature produces soft and hard materials exhibiting remarkable functional properties by controlling the hierarchical assembly of simple molecular building blocks from the nano- to the macro-scale. Biogenic materials are nucleated in defined nano–micro-dimensioned sites inside the biological environments, in which chemistry can be spatially controlled, in order to monitor the size, shape, and structural organization of biomaterials. With the development of nanotechnology, this strategy employing natural material genesis has attracted attention in designing bioinspired materials at the nanoscale dimensions. In this contest, biomimetic nanostructured hydroxyapatite is a promising biomaterial for bone tissue engineering because this material exhibits excellent biological properties. However, hydroxyapatite is still limited as bone substitute due to the brittleness of the material. Hence, a widespread approach is the creation of hybrid materials with an inorganic or organic bioactive phase mimicking functional bony units and a polymeric phase of a consistency permitting the device to be manipulated to achieve an anatomically compatible shape and allowing surface adsorption of molecules that play active roles in the biological environment. Recently, many studies were developed in order to prepare and test new bioengineered custom-made composite scaffold materials using a combination of CAD/CAM technology to restore full-thickness defects of the bone. Modern 3D printing techniques allow dimensioning of the external volume according to the surgical defect, thus simplifying the surgery and reducing biological morbidity. The use of CAD/CAM technology and the novel composite, biomimetic, and resorbable scaffolds are the promising way to interpret the need of bone regenerative medicine.