Shape Memory Alloys for Biomedical Applications

Shape memory metals are suitable for a wide range of biomedical devices including applications in dentistry, bone repair, urology and cardiology. This book provides a thorough review of shape memory metals and devices for medical applications. The first part of the book discusses the materials, primarily Ti-Ni based alloys; chapters cover mechanical properties, thermodynamics, and composition as well as fabrication of parts, chemical reactivity, surface modification, and biocompatibility. It book also covers stents, orthodontic devices and endodontic instruments. Finally, future developments in this area are discussed including alternatives to Ti-Ni based shape memory alloys.

PART 1 MATERIALS

The Shape Memory Effect and Superelasticity in Ti-Ni Alloys
S Miyazaki, University of Tsukuba, Japan and R Sachdeva, OraMetrix, USA
Introduction. Shape memory effect and superelasticity. Elasticity and superelasticity. Superelasticity in clinical orthodontics. Superelasticity characteristics. Extraporation factors affecting superelasticity. Conclusions. References.

Mechanical Properties of Shape Memory Alloys
H Hosoda and T Inamura, Tokyo Institute of Technology, Japan
Introduction. The type of shape memory material. Martensitic transformation. Shape-memory effect. Bidirectional shape memory effect: pseudoelasticity. Superelastic effect. Superelastic temperature range of shape memory. The shape memory alloy deformation mechanism. The type of shape memory alloy. Superelastic biomedical titanium alloy. Superelasticity. Conclusions. References.

Thermodynamics of the Shape Memory Effect in Ti-Ni Alloys
Y Liu, The University of Western Australia, Australia
Thermal-mechanical coupling of thermoelastic martensitic transformation. Thermoelasticity of martensitic transformations. Equilibrium thermodynamic theory of thermoelastic martensitic transformations. Phenomenological thermodynamic theory of thermoelastic martensitic transformations. Unified thermodynamic expression of thermoelastic martensitic transformations. Thermodynamic expression of transformation temperatures. Transformation heats. Experimental verifications and interpretations. Generality of thermodynamic theories of thermoelastic martensitic transformations. Summary. References.

Alternative Ti-Based Shape Memory Alloys for Biomedical Applications
H Y Kim and S Miyazaki, University of Tsukuba, Japan
Introduction. Shape memory effect and superelasticity in Ti-Nb based alloys. Effect of interstitial alloying elements on shape memory properties of Ti-based shape memory alloys (SMAs). Effect of heat treatment condition on shape memory properties of Ti-based shape memory alloys. Effect of textures on shape memory properties of Ti-based shape memory alloys. Ti-Mo based shape memory alloys. Ti-V based shape memory alloys. Conclusions. References.

Fabrication of Shape Memory Alloy Parts
T Habu, Furukawa Techno Material Co. Ltd, Japan
General processing techniques for Ti-Ni alloys. Other machining methods for Ti-Ni alloys. Required properties of Ti-Ni alloys used in medical devices. Future trends. References.

Response of Ti-Ni Alloys For Dental Biomaterials to Conditions in the Mouth
Y Oshida, Syracuse University and Indiana University, USA and F Farzin-Nia, Ormco Corporation, USA
Introduction. Discoloration. Corrosion of Ti-Ni alloys in various media. Corrosion behaviour of Ti-Ni alloys in fluoride containing solution. Corrosion behaviour of Ti-Ni alloys in chlorine ion containing solution. Corrosion behaviour of Ti-Ni alloys in artificial saliva. Corrosion behaviour of Ti-Ni alloys in simulated body fluid. Effects of alloying elements to Ti-Ni alloy on corrosion resistance. Effect of surface modification on corrosion resistance. Metal ion release and dissolution of Ti-Ni alloys. Allergic reaction, toxicity, and biocompatibility of Ti-Ni alloys. Galvanic corrosion of Ti-Ni alloys. Microbiology-induced corrosion (MIC) of Ti-Ni alloys. Formation of titanium oxides. Air-formed titanium oxide. Passivation of Ti-Ni alloys. Oxidation at elevated temperatures. Crystal structures of titanium oxides. Characterization of oxides. Oxide growth, stability and breakdown. Reaction of titanium oxides with hydrogen peroxide. Reaction of titanium oxides with hydrogen. References.

Understanding, Predicting And Preventing Failure of Ti-Ni Shape Memory Alloys used in Medical Implants
K Gall, Georgia Institute of Technology, USA
Introduction. Overview of Ti-Ni mechanical failure modes. Inelastic deformation and fracture. Fatigue failure and life analysis. Influence of processing and material structure on material failure. Influence of manufacturing and surface finish on material failure. Summary and future trends. Sources of further information and advice. References.

Surface Modification of Ti-Ni Alloys for Biomedical Applications
M F Maitz, Leibniz Institute of Polymer Research Dresden, Germany
Introduction. Surface finishing. Surface passivation. Coatings. Sterilization. Summary. References.

Biocompatibility of Nitinol for Biomedical Applications
S Shabalovskaya, Ames Laboratory, USA and J Van Humbeeck, Katholieke University Leuven, Belgium
Introduction. Biomechanical compatibility. Comparative metal toxicity. Patterns of nickel release from Nitinol. Response of cells to Ni release. Thrombogenic potential, platelet adhesion and protein adsorption. Biological responses to modified Nitinol surfaces. In vivo responses. Conclusions and future trends. References.

PART 2 MEDICAL AND DENTAL DEVICES

Self-Expanding Nitinol Stents for the Treatment of Vascular Disease
D Stoeckel, A Pelton and T Duerig, Nitinol Devices & Components, USA
Introduction. Nitinol specific device characteristics. Nitinol stent designs. Biocompatibility and corrosion. Fatigue and durability of Nitinol stents. Sources of further information and advice. References.

Orthodontic Devices Using Ti-Ni Shape Memory Alloys
F Farzin-Nia, Ormco corporation, USA and T Yoneyama, Nihon University School of Dentistry, Japan
Introduction. Wire properties in various stages of orthodontic treatment. Evolution of orthodontics wires. Ti-Ni orthodontic archwires. Ti-Ni based alloy wires – Effects of additional elements. Chemical properties in oral environment. Other orthodontic appliances. Future trends. References.

Endodontic Instruments for Root Canal Treatment Using Ti-Ni Shape Memory Alloys
T Yoneyama, Nihon University School of Dentistry and C Kobayashi, Tokyo Medical and Dental University, Japan
Root canal treatment. Stainless steel instruments. Ti-Ni alloy instruments. Root canal preparation system with Ti-Ni alloy instruments. Future development of Ti-Ni alloy instruments. References.

Orthopaedic, Dental, Endovascular and Other Applications of Ti-Ni Shape Memory Alloys
L ‘H Yahia and F Rayes, École Polytechnique de Montréal and A O Warrak, University of Montreal, Canada
Introduction. USA food and drug administration (FDA) status of Ti-Ni medical devices. Orthopedic/dental applications of Ti-Ni shape memory alloys. Endovascular applications or interventions. Other applications of Ti-Ni shape memory alloys. Conclusions. References.