Multiscale Electrochemical Investigation of the Corrosion Resistance of Various Alloys Used in Dental Prostheses
- PDF / 2,570,236 Bytes
- 11 Pages / 593.972 x 792 pts Page_size
- 72 Downloads / 180 Views
I.
INTRODUCTION
METALS are more suitable than ceramics or polymeric materials for biomedical implantation in the case of load-bearing applications because they combine high mechanical strength and fracture toughness.[1–6] Orthopedists, clinicians, and other investigators are thus seeking better metallic materials for applications in dental engineering. Unfortunately, metallic materials experience corrosion and wear processes in physiological environments resulting in the release of toxic metallic ions that can originate various adverse tissue reactions and/or hypersensitivity reactions.[7] Therefore, the study of the corrosion behavior and the degree of tolerance by tissues of the wide variety of dental alloy products commercially available—diverse in both their composition and their applications or performance—has been encouraged. In fact, corrosion resistance is a very important property for dental alloys. Corrosion of dental alloys in the oral environment not only results in the deterioration of the restoration, but also involves SORIN IACOBAN, Ph.D. Student, and CORNELIU MUNTEANU, Professor, are with the Faculty of Mechanical Engineering, "Gheorghe Asachi" Technical University of Iasi, 700050 Iasi, Romania. DANIEL MARECI, Associate Professor, and GEORGIANA BOLAT, Ph.D. Researcher, are with the Faculty of Chemical Engineering and Environmental Protection, "Gheorghe Asachi" Technical University of Iasi. Contact e-mail: [email protected] RICARDO MANUEL SOUTO, Professor, is with the Department of Chemistry, University of La Laguna, P.O. Box 456, 38200 La Laguna, Tenerife, Canary Islands, Spain, and also with the Department of Physical Chemistry, University of La Laguna, La Laguna, Spain. Manuscript submitted July 18, 2014. METALLURGICAL AND MATERIALS TRANSACTIONS B
the release of metal ions that directly influences their biocompatibility.[8,9] The corrosion resistance of metals and alloys is due to the spontaneous formation of a thin, compact layer of oxides named the passive layer. The chemical composition of the passive layers, their thickness, and the degree of protection that they can provide to the corresponding materials are related to a number of factors connected with the chemical environment, the composition and microstructure of the alloys, mechanical stresses, etc. Despite these differences, degradation occurs on biomaterials surfaces due to the chemical reactions between passive oxide layer and chloride ions present in the environment in which they are placed. Ag-Pd alloys have been used in prosthetic dentistry in recent years because of their low price compared with gold, although they are more expensive than Co-Cr or Ni-Cr alloys. Yet, the biological safety of Pd in dental alloys has become a matter of concern in recent years, motivated by reports on the frequent incidence of ‘‘Pdallergy.’’[10] Because of these problems, many practitioners use non-precious alloys such as Ni-Cr or Co-Cr instead. These alloys, thanks to their excellent properties, are frequently employed to manufacture crowns, b
Data Loading...
