Apatitas nanoparticuladas incorporadas a matrizes poliméricas para aplicação odontológica

Abstract

Hybrids biomaterials based on calcium phosphates have been investigated extensively for applications in biomedicine and restorative dentistry. Accordingly, nanoparticles have been incorporated into dental materials and bone regeneration to improve the physical and mechanical properties. Therefore, in this work we have synthesized and incorporated inorganic nanoparticles to polymer matrices to produce four systems: (1) resins infiltrants capable of combating enamel demineralization; (2) radiopaque dental restorative resins and (3) collagen-based scaffolds applied to the regeneration of bone tissue. Hydroxyapatite (HAp) and strontium hydroxyapatite (SrHAp) nanoparticles were prepared by co-precipitation and subjected to different thermal treatments, obtaining crystals with different properties, as crystallinity, crystallite size, surface and morphology. Initially, HAps were synthesized with control of morphology and crystallite size and then incorporated into a light-curing co-monomer resin blend (control) to create different resin-based enamel infiltrants. Incorporation of high crystallinity HAp nanopeds (HAp2 and HAp5 h) in enamel infiltrating resin increased significantly the degree of conversion (GC), increased the resistance against demineralization and, therefore, showed a viable method to improve the performance in the prevention of demineralization in infiltrating resin enamel. In the second part of the work, strontium phosphates were prepared with different heat treatments to obtain pure and highly crystalline SrHAp. The results of DRX, FT-IR and Raman confirmed that the SrHAp5h sample showed a single SrHAp phase and the MET images showed a stick morphology. The TEM images revealed nanorods morphology for SrHAp5h. SrHAps incorporated into adhesive showed higher radiopacity, no alteration on DC. Although the mechanical properties are slightly impaired, incorporation of SrHAp nanoparticles offers potential method to improve radiopacity of restorative dental resins, easing the tracking of actual remineralization effects and enabling diagnosis of recurrent caries. Finally, scaffolds based on anionic collagen extracted from swine viscera were prepared and Hap nanoparticles impeached in their structure. The viability, adhesion and activation of in vitro osteoblasts of the produced biocomposites was evaluated. Besides being biocompatible, Col+HAp5h scaffold presented significant effects on osteoblasts viability, proliferation and activity. Our findings strongly encourage the use of this biomaterial in the regeneration of bone defects in future assays.