Porous Titanium Cylinders Obtained by the Freeze-Casting Technique: Influence of Process Parameters on Porosity and Mechanical Behavior

Paloma Trueba,José Antonio Rodríguez-Ortiz,Yadir Torres,David C Dunand,Ana M Beltrán,Esteban Alonso,Diego F Larios,José Manuel Bayo

doi:10.3390/met10020188

Paloma Trueba, José Antonio Rodríguez-Ortiz + Show 6 more

Open Access

https://doi.org/10.3390/met10020188

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Abstract

The discrepancy between the stiffness of commercially pure titanium and cortical bone tissue compromises its success as a biomaterial. The use of porous titanium has been widely studied, however, it is still challenging to obtain materials able to replicate the porous structure of the bones (content, size, morphology and distribution). In this work, the freeze-casting technique is used to manufacture cylinders with elongated porosity, using a home-made and economical device. The relationship between the processing parameters (diameter and material of the mold, temperature gradient), microstructural features and mechanical properties is established and discussed, in terms of ensuring biomechanical and biofunctional balance. The cylinders have a gradient porosity suitable for use in dentistry, presenting higher Young’s modulus at the bottom, near the cold spot and, therefore better mechanical resistance (it would be in contact with a prosthetic crown), while the opposite side, the hot spot, has bigger, elongated pores and walls.

Highlights

IntroductionMore than 50 million people have some type of prosthesis or implants [1]. In addition, in recent decades, life expectancy has categorically increased and, the requirements for implants are more demanding under the criteria of durability and quality of life of patients [2].Four generations of biomaterials have been already developed: (1) inert biomaterials; (2) bioactive or biodegradable materials; (3) bioactive and biodegradable materials, at the same time; and (4)those materials that have the ability to stimulate specific cells to help the body to heal and naturally repair its own tissues, following physiological processes [3]
Nowadays, more than 50 million people have some type of prosthesis or implants [1]
We evaluate the influence of thermal gradient the diameter and material of the freezing mold, as well as the particle sizes and growth rate of solidification front, on the obtained porosity: volumetric fraction, size, distribution and morphology

Summary

Introduction

More than 50 million people have some type of prosthesis or implants [1]. In addition, in recent decades, life expectancy has categorically increased and, the requirements for implants are more demanding under the criteria of durability and quality of life of patients [2].Four generations of biomaterials have been already developed: (1) inert biomaterials; (2) bioactive or biodegradable materials; (3) bioactive and biodegradable materials, at the same time; and (4)those materials that have the ability to stimulate specific cells to help the body to heal and naturally repair its own tissues, following physiological processes [3]. More than 50 million people have some type of prosthesis or implants [1]. In recent decades, life expectancy has categorically increased and, the requirements for implants are more demanding under the criteria of durability and quality of life of patients [2]. Four generations of biomaterials have been already developed: (1) inert biomaterials; (2) bioactive or biodegradable materials; (3) bioactive and biodegradable materials, at the same time; and (4). Those materials that have the ability to stimulate specific cells to help the body to heal and naturally repair its own tissues, following physiological processes [3]. Despite being recognized because of their high specific mechanical properties and excellent

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