In vitro apatite formation on chemically treated (P/M) Ti–13Nb–13Zr

Müller, Frank A.; Bottino, Marco C.; Müller, Lenka; Henriques, Vinicius A.R.; Lohbauer, Ulrich; Bressiani, Ana Helena A.; Bressiani, José C.

doi:10.1016/j.dental.2007.02.005

« Previous Next »Dental Materials
Volume 24, Issue 1 , Pages 50-56, January 2008

In vitro apatite formation on chemically treated (P/M) Ti–13Nb–13Zr

Frank A. Müller
- Department of Materials Science (III)-Biomaterials, University of Erlangen-Nuernberg, Erlangen, Germany
Marco C. Bottino
- Materials Science and Technology Center, Institute for Energy and Nuclear Research (IPEN), São Paulo, SP, Brazil
- Department of Materials Science and Engineering, University of Alabama at Birmingham, 1530 3rd Ave South, BEC 254, Birmingham, AL 35294-4461, United States
- Corresponding author at: Department of Materials Science and Engineering, University of Alabama at Birmingham, 1530 3rd Ave South, BEC 254, Birmingham, AL 35294-4461, United States. Tel.: +1 205 934 6970; fax: +1 205 934 8485.
Lenka Müller
- Department of Materials Science (III)-Biomaterials, University of Erlangen-Nuernberg, Erlangen, Germany
Vinicius A.R. Henriques
- Materials Division (AMR-IAE) – CTA Brazilian Aerospace Technical Center, São José dos Campos, São Paulo, Brazil
Ulrich Lohbauer
- Dental Clinic 1 – Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany
Ana Helena A. Bressiani
- Materials Science and Technology Center, Institute for Energy and Nuclear Research (IPEN), São Paulo, SP, Brazil
José C. Bressiani
- Materials Science and Technology Center, Institute for Energy and Nuclear Research (IPEN), São Paulo, SP, Brazil

Received 23 March 2006; received in revised form 16 January 2007; accepted 5 February 2007.

Abstract

Objectives

Titanium alloys are considered the material of choice when used as endosteal part of implants. However, they are not able to bond directly to bone. The objective of this study was to suggest a chemical surface treatment for Ti–13Nb–13Zr to initiate the formation of hydroxy carbonated apatite (HCA) during in vitro bioactivity tests in simulated body fluid (SBF).

Methods

Titanium, niobium, and zirconium hydride powders were blended, compacted and sintered. Sintered Ti–13Nb–13Zr samples were etched in HCl, H₃PO₄, and in a mixture of HF+HNO₃, respectively, and subsequently pretreated in NaOH. The influence of acid etching conditions on the microstructure of the Ti–13Nb–13Zr alloys as well as on the rate of HCA formation was evaluated using SEM-EDS, FTIR, and gravimetric analyses.

Results

Sintered Ti–13Nb–13Zr alloys consist of a Widmannstätten (α+β) microstructure. Exposure of chemically etched and NaOH activated samples to SBF for 1 week leads to the formation of a HCA layer on the surface of HCl as well as H₃PO₄ treated samples. No HCA formation was found on HNO₃ treated samples. After 2 weeks in SBF the mass increase, that can be correlated to the HCA formation rate, was the highest for HCl pretreated samples (2.4mg/cm²) followed by H₃PO₄ (0.8mg/cm²) and HNO₃ pretreated ones (0.2mg/cm²).

Significance

Since the in vitro HCA formation from SBF is generally accepted as a typical feature for bioactive materials, it is supposed that HCl etching with subsequent NaOH treatment might enhance the in vivo bone-bonding ability of Ti–13Nb–13Zr.

Keywords: Titanium alloys, Powder metallurgy, Simulated body fluid, Surface modification, Bioactivity