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Título/Title/Titulo

STERILIZATION PROCESSES OF NATURAL SCAFFOLDS FOR TISSUE ENGINEERING

Introdução/Introduction/Introdución

Tissue Engineering (TE) is a multidisciplinary science dedicated to producing organs and human parts replaced by traumatic lesions, degenerative diseases or agenesis. One of its stages is the production of biocompatible frameworks for application in Regenerative Medicine. These structures are known as scaffolds, they are similar to the original tissue in texture and porosity. Moreover, it drives the behavior of the cells that will be sown, leading to a construct. The treatment of extensive losses is very difficult and challenging, as the complete recovery of the anatomical and functional integrity of damaged tissues not only provides physical and psychological improvement but also can mean the survival of the patients. The use of natural scaffolds involves the removal of living cells from the organ/tissue and let it read to be implanted in humans, and its biosafety implies being sterile, and with its macro and micro-geometry preserved.

Objetivos - Metodologia - Resultados - Discussão dos Resultados/Objectives - Methodology - Results - Discussion of Results/Objetivos - Metodología - Resultados - Discusión de los resultados

Objective: Evaluate the efficiency of sterilization after demineralization and decellularization of the teeth, enabling them as natural scaffolds. Methods: The samples were submitted to demineralizing/decellularising solutions in sequence sterilizing them. All of them were processed with 28% EDTA, 9% hydrogen peroxide, enzymatic detergent; they were divided into 5 groups: G1 - control, G2 - sterilization with dry heat, G3 - sterilization with autoclave, G4 - sterilization with ethylene oxide; G5 - sterilization with Gamma radiation.
The evolution of demineralization and decellularization was accompanied by weighing, analytical techniques SEM (Scanning Electron Microscopy), optical images and radiography. Samples were weighed before and after the sterilization process.
The sterility test evaluation were performed to evaluate the microbial growth. The results were statistically analyzed by Friedman, Kruskal-Wallis, Qui-square test and Fisher's exact test. The level of rejection of the null hypothesis was set at 0.05 or 5%. The presented results indicates all the 4 sterillization methods presented equivalent good performance, radiographically there were no evident advantage for any of them. At groups G2 and G4 the color of the samples did not change, while in group G3 the root portion became yellowish and in G5 the coronary portion became greyed. In G5, the microhardness test presented lower levels. Conclusion: Although the demineralization/decellularization processes are not sufficient to eliminate all microorganisms present in the evaluated samples, the sterilization processes performed have been shown to be effective in eliminating the bioburden.

Considerações Finais/Final considerations/Consideraciones finales

Support -This work was supported by Universidade Federal São Paulo, São Paulo, Brazil, CAPES, CNPq Productivity Scholarship (SED -307389/2015-4 level 1D; MTD306972/2015-8 level 2)FAPESP 2013/00288-4; 2013/06877-1; INCT- National Institute of Science and Technology –Biofabrication InstituteBiofabris,CNPq, 573661/2008-1, FAPESP 08/57860-3.

Palavras-chave/Key words/Palabras clave

sterilization processes; tissue engineering; demineralization/ decellularization