Advances using hydroxyapatite as a biomaterial in bone regeneration

Abstract

Objective: This thesis aims at analyzing and discussing new strategies for bone filling, using hydroxyapatite as a template, which is able to promote a bioactive behavior and consequently regeneration. The new approaches using hydroxyapatite will be compared with the more conventional strategies. This thesis intends also to answer several questions such as: what are the mediators that promote/participate in bone regeneration, how these mediators allow bone regeneration, as well as the possible advantages of using three-dimensional models with the exact shape of the defect that needs to be filled. Methodology: A bibliographic search of the state of the art was performed, examining studies published in the last 5 years of research, products in clinical phase of development and new methodologies still in pre-clinical phase (in vitro and in vivostudies). The practical component of this thesis will consist in the analysis of commercial bone filling hydroxyapatite material (eg, Bio-Oss ®) by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD)and Specific surface area.Results: The characterization of biomaterials composed of bovine bone inorganic matrix revealed that those are bony matrix with excess of calcium. The differences in the molar ratio Ca / P were not significant. The samples showed differences in the crystalline surface appearance, since Cerabone® presented a crystalline appearance comparatively to the remaining bone substitutes. A relationship between the degree of crystallinity and the processing temperature has been established. The overall results showed that the incorporation of biomolecules in HA scaffolds lead to better bioactivity and osteogenic differentiation by improving cell proliferation and differentiation whichstimulates faster bone formation with low rate resorption. This last fact has a crucial importance because the slow resorption keeps the volume leading to a good dimension of the new bone.Conclusion: The incorporation of biomolecules in bone osteoconductive matrix improves the process of osteogenesis.

Date of Award	2014
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Ana Leite Oliveira (Supervisor) & Filipe Miguel Araújo (Co-Supervisor)