Reconstruções de tecidos ósseos: biomaterial injetável à base de fosfatos de cálcio.

Abstract

Injectable bone substitutes (IBS) consisting of calcium phosphates (CaPs) are the subject of intense and constant investigation. Injection of these compounds can reduce the duration of surgical interventions, minimize side effects and postoperative pain for the patient. Therefore, there is a faster recovery of the patient and reduction of hospital costs. The objective of the present work was to prepare an IBS composed of a mixture of two phases, a solid phase in the form of spherical granules of hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP), and a liquid phase in the form of a hydrogel composed of chitosan (CHI) and polyethylene glycol (PEG). From the obtained results, it was possible to obtain granules in the form of CaPs beads through an atomizer, composed of 26,9% HA and 73,1% β-TCP, with average diameters below 600 µm having rough and microporous surface. The hydrogel produced by CHI/PEG blend is miscible and the viscosity of the polymer blend is shear rate dependent with a non-Newtonian shear thinning behavior. The conformation of the IBS gave rise to a biomaterial in the form of an agglomerate of pasty consistency and without loss of continuity, which favors its applicability in an injectable form. Mechanical and injectability tests have shown that the forces required for the complete removal of the interior of a commercial syringe from both the hydrogel and the IBS 1-1 250-500 µm are constant and are in a range that will not disrupt the injection precision of the product within a bone defect at the time of its use. Biological tests in vitro and in vivo did not presente citotoxic effetcs and showed promising results in filling bone defects created in rabbit tibias, regarding osseointegration and bone neoformation at 30 and 60 postoperative days. It is concluded that from the obtained results, it is possible to develop an IBS with potential application in the area of orthopedics and dentistry.