Papers by Author: B. de M. Purquerio

Abstract: Ceramic scaffolds, mechanically qualified, highly porous, non biodegradable and with bioactive coating have been manufactured. The aim of this study was evaluated mechanical and in vivo responses of the porous alumina scaffolds with bioactive coating. The bioactive coating was performed under vacuum with bio-glass (45S5®)) and hydroxyapatite (HAp). Alumina ceramics (Al2O3) are used for bone implants in function of the biocompatibility and the high mechanical reliability of this material. Unfavourably alumina is a bioinert material and bone ingrowths are hard to occur and any implant anchorage becomes difficult. To improve this, ceramic scaffold samples were made with porosity concentration around 75vol% and with average pores diameters around 190.0µm. They were mechanically characterized through macro and micro structural analyses and mechanical tests and biologically through cell culture tests with fibroblastic VERO cell line for cytotoxicity and animal experiments on tibiae rats – Rattus norvegiicus albinos – aiming histological and line scan analysis in order to check the scaffold-bone cellular interaction. Current results seem to suggest the promising properties of the bioactive coated alumina ceramic scaffolds tested. The concentration of 75vol% alumina showed to be the great alternative for an economical solution for porous alumina ceramic scaffolds related to the mechanical properties and bone integration.

Abstract: The objective of this study was to manufacture porous scaffolds with bioinert and bioactive materials to join mechanical properties and bony integration. Porous alumina ceramic matrices were produced using the slurry technique followed by isostatic pressing, leaching and sintering. Porous alumina samples presented 75.0vol% porosity and 52.27MPa of compressive strength. Bioglass/hydroxyapatite ceramic slurry was used as coating on alumina matrices. The infiltration was performed by dipping the alumina porous samples into bio-glass/hydroxyapatite ceramics slurry under vacuum and followed by sintering. The evaluation of the alumina ceramic scaffolds samples were made using EDX, mechanical and in vitro tests. For the in vitro tests, fibroblastic VERO cell line was employed. The porous alumina ceramic coated acquired a higher strength and more pronounced cell interaction than the non coated alumina scaffolds.

Abstract: Non metallic materials like polyurethane has been successfully used for bone reconstruction in general and specifically in craniofacial and in mandible surgeries as an implantable material. However, any polymer alone cannot be universally successful as a medical device or structural implant because the eventual lack of well defined porous geometry, inherent interconnected porosity, the non dispensable need for a combined mechanical behavior with biological interaction and manufacturing feasibility. In this work, a bioactive material composite with high mechanical strength was designed using a castor oil polyurethane (PU) structure with a functional gradient having a dense core and a porous bioactive surface. The models and replicas for the implants were processed with Rapid Prototyping (RP) techniques and their application (case studies) were fulfilled according to the SUS (Brazilian Health Service) with the support of Santa Tereza Hospital, Petropolis, RJ.

Abstract: A material able to be used as bone implant for specific applications was developed. The proposed solution establishes that all implant surfaces should be bioactive since porous surfaces in contact with bone are extremely necessary for bone adhesion. The bioactive material composite with high mechanical strength designed with a PMMA functional structure gradient produced in this work has a dense core enveloped by a porous bioactive surface. Pore sizes and shapes as well their interconnectivity was analyzed by SEM tests; the cytotoxicity was investigated in vitro using Vero cell and bone conductivity and biocompatibility was investigated in vivo in rabbits. The implant porous bioactive part analyzed in vitro showed no toxicity and tests in vivo showed a remarkable biocompatibility and bone cell growth. Some samples with hydroxyapatite (HAp) were analyzed by EDX and SEM tests, the results showed a fair hydroxyapatite distribution in the implant pore surfaces as much as a part which was retained inside the PMMA inner porous. The average scaffold pore sizes obtained was around 250.0µm and the diameter shrinkage of 4.0% was observed in all samples. This study demonstrated that the functional gradient structure composite studied can be a good candidate for cranial bone implants due to its good bone conductivity and biocompatibility.