Handbook of Biomaterial Properties

Handbook of Biomaterial Properties

Edited by

Jonathan Black Professor Emeritus of Bioengineering

Clemson University USA

and

Garth Hastings Professor and Director of the Biomaterials Programme

Institute of Materials Research and Engineering National University of Singapore

[U!11 SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

First edition 1998

© 1998 Springer Science+Business Media Dordrecht Originally published by Chapman & Hall in 1998 Softcover reprint of the hardcover 1st edition 1998

Thomson Science is a division of International Thomson Publishing

Typeset in 10/12 pt Times by Florencetype Ltd, Stoodleigh, Devon

ISBN 978-0-412-60330-3 ISBN 978-1-4615-5801-9 (eBook) DOI 10.1007/978-1-4615-5801-9

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publishers. Applications for permission should be addresed to the rights manager at the London address of the publisher.

The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made.

A catalogue record for this book is available from the British Library

Contents

Foreword xiii Introduction xv Contributors xviii

PART I

A1 Cortical bone 3 f Currey ALl Composition 3 A1.2 Physical properties 4 A1.3 Mechanical properties 5 Additional reading 12 References 12

A2 Cancellous bone 15 TM. Keaveney A2.1 Structure 16 A2.2 Composition 16 A2.3 Mechanical properties 16 Additional reading 21 References 21

A3 Dentin and enamel 24 K.E. Healy A3.1 Introduction 24 A3.2 Composition 25 A3.3 Final comments 35 Additional reading 36 References 37

B1 Cartilage 40 f.R. Parsons B1.1 Introduction 40 B1.2 Composition 41 B 1.3 Mechanical properties of articular cartilage 41

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B1.4 Fibrocartilage mechanical properties 45 B 1.5 Elastic cartilage mechanical properties 45 Additional reading 45 References 46

B2 Fibrocartilage 48 V.M. Gharpuray B2.1 Introduction 48 B2.2 Structure and composition 48 B2.3 Hydraulic permeability and drag coefficients 51 B2.4 Elastic properties 51 B2.5 Viscoelastic behaviour 53 B2.6 Discussion 54 Additional reading 55 References 56

B3 Ligament, tendon and fascia 59 S.L.-Y. Woo and R.E. Levine B3.1 Introduction 59 B3.2 Discussion 62 Additional reading 62 References 63

B4 Skin and muscle 66 A.F.T. Mak and M. Zhang B4.1 Introduction 66 B4.2 In vivo mechanical properties 66 Additional reading 68 References 69

B5 Brain tissues 70 S.S. Margulies and D.F. Meaney B5.1 Introduction 70 B5.2 Composition 71 B5.3 Mechanical properties 72 B5.4 Electrical properties (no primate data available) 77 B5.5 Thermal properties 77 B5.6 Diffusion properties 77 B5.7 Comments 78 Additional reading 78 References 79

B6 Arteries, veins and lymphatic vessels 81 X. Deng and R. Guidoin B6.1 Introduction 81 B6.2 Morphometry of the arterial tree and venous system 82 B6.3 Constituents of the arterial wall 82 B6.4 Constituents of the venous wall 88 B6.5 Mechanical properties of arteries 88

CONTENTS I I vii

B6.6 Mechanical properties of veins 96 B6.7 Mechanical characteristics of lymphatic vessels 98 B6.8 Transport properties of blood vessels 98 B6.9 Effect of age, hypertension and atherosclerosis

on blood vessels 99 B6.10 Final comments 100 Acknowledgement 101 Additional reading 101 References 102

B7 The intraocular lens 106 T. V. Chirila B7.1 Introduction 106 B7.2 Chemical composition 107 B7.3 Dimensions and optical properties 109 Additional reading 112 References 112

Cl Blood and related Ooids 114 V. Turitto and S.M. Slack C1.1 Introduction 114 Additional reading 123 References 123

C2 The vitreous humour U5 T. V. Chirila and Y. Hong C2.1 Introduction 125 C2.2 General properties 126 C2.3 Mechanical properties 129 Additional reading 129 References 130

PARTD

1 Metallic biomaterials 135 J. Breme and V. Biehl 1.1 Introduction 135 1.2 General discussion 137 References 143

la Stainless steels 145 1a.1 Composition 145 1a.2 Physical properties 150 1a.3 Processing of stainless steels 151 1a.4 Mechanical properties 157 1a.5 Fatigue 161 1a.6 Corrosion and wear 163 1a.7 Biological properties 165 References 165

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1b CoCr-based alloys 167 1b.1 Composition 167 1b.2 Physical properties 169 1b.3 Processing of CoCr-alloys 169 1bA Mechanical properties 173 1b.5 Fatigue 174 1b.6 Corrosion and wear 175 1 b.7 Biological properties 177 References 178

1e Titanium and titanium alloys 179 1c.1 Composition 179 1c.2 Physical properties 180 1c.3 Processing of cp-Ti and Ti alloys 181 1cA Mechanical properties 186 1c.5 Fatigue 189 1c.6 Corrosion and wear 194 1c.7 Biological properties 197 1c.8 TiNi-shape memory 198 References 198

1d Dental restoration materials 201 1d.1 Amalgams 201 1d.2 Noble metals 204 1d.3 CoCr-alloys 212 1dA NiCr-alloys 212 References 213

2 Composite materials 214 L. Ambrosio, G. Carotenuto and L. Nicolais 2.1 Types of composites and component materials 214 2.2 Fibre types and properties 214 2.3 Matrix materials 219 204 Thermoplastic matrix 219 2.5 Thermosets matrix 220 2.6 Vinyl ester resins 221 2.7 Epoxide resins 221 2.8 Diluents 222 2.9 Curing agents for epoxide resins 222 2.10 Polyester resins 224 2.11 Laminate properties 225 2.12 Composite fabrication 229 2.13 Mechanical properties 240 2.14 Antioxidants and effect of environmental exposure 254 2.15 The radiation stability of commercial materials 256 2.16 Polymers aging 259 2.17 Composite materials in medicine 260

CONTENTS I I ix

2.18 Metal matrix composites 262 2.19 Ceramic matrix composites 266 References 269

3 Thermoplastic polymers in biomedical applications: structures, properties and processing 270 S.H. Teoh, Z.C. Tang and C. W. Hastings 3.1 Introduction 270 3.2 Polyethylene 272 3.3 Polypropylene 273 3.4 Polyurethane 274 3.5 Polytetraftuoroethylene 275 3.6 Polyvinylchloride 276 3.7 Polyamides 277 3.8 Polyacrylates 278 3.9 Polyacetal 279 3.10 Polycarbonate 280 3.11 Polyethylene terephthalate 281 3.12 Polyetheretherketone 282 3.13 Polysulfone 283 References 300

4 Biomedical elastomers 302 ]. W. Boretos and ].Boretos 4.1 Introduction 302 4.2 Types of elastomers 303 4.3 Establishing equivalence 334 4.4 Sterilization of elastomers 338 4.5 Relevant ASTM Standards 338 4.6 Biocompatibility 338 4.7 Sources 338

5 Oxide bioceramics: inert ceramic materials in medicine and dentistry 340 ]. Li and C. W. Hastings 5.1 Introduction 340 5.2 Short history 340 5.3 Material properties and processing 342 5.4 Biocompatibility of oxide bioceramics 348 5.5 Applications 351 5.6 Manufacturers and their implant products 352 5.7 Problems and future prospects 352 References 352

6 Properties of bioactive glasses and glass-ceramics 355 L.L. Hench and T. Kokubo 6.1 Bioactive bonding 355 6.2 Bioactive compositions 357

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6.3 Physical properties 358 References 362

7 Wear 364 M. LaBerge 7.1 Introduction 364 7.2 In vitro wear testing 369 7.3 Clinical wear 393 7.4 Combined wear and fatigue 393 7.5 Solving the wear problem 394 7.6 Conclusion 395 Acknowledgements 399 Additional reading 399 References 400

8 Degradation/resorption in bioactive ceramics in orthopaedics 406 H. Oonishi and H. Oomamiuda 8.1 Introduction 406 8.2 In vitro physico-chemical dissolution processes 407 8.3 In vivo/in vitro biological degradation processes 410 8.4 Summary 417 References 417

9 Corrosion of metallic implants 420 M.A. Barbosa 9.1 General aspects 420 9.2 Aspects related to the metal composition 423 9.3 Aspects related to the physiological environment 429 9.4 Aspects related to the oxide and other surface layers 436 References 458

10 Carbons 464 A.D. Haubold, R.B. More and J.e. Bokros 10.1 Introduction 464 10.2 Historical overview - in vivo applications 472 10.3 New directions/future trends 474 References 475

PART 01

1 General concepts of biocompatibility 481 D.F. Williams 1.1 Introduction 481 1.2 The definition of biocompatibility 482 1.3 Components of biocompatibility 484 1.4 Conclusions 488 Additional reading 488 References 489

CONTENTS I I xi

2 Soft tissue response 490 1.M. Anderson 2.1 Introduction 490 2.2 Types of response 490 2.3 Inflammation 492 2.4 Wound healing and fibrosis 494 2.5 Repair of implant sites 495 2.6 Summary 496 Additional reading 497 References 498

3 Hard tissue response 500 T. Albrektsson 3.1 Introduction 500 3.2 Fixation by cementation 500 3.3 Fixation by ingrowth (cement-free implants in bone) 503 3.4 Osseointegration 504 3.5 How bone-biomaterial interfaces fail 507 3.6 Conclusions 508 Additional reading 510 References 510

4 Immune response 513 K. Merritt 4.1 Introduction 513 4.2 Overview of the specific immune response 513 4.3 Detection of antibody 515 4.4 Detection of cell mediated responses (Type IV) 517 4.5 Detection of immune responses to haptens 521 4.6 Human immune response to materials 521 4.7 Consequences of an immune response 523 4.8 Conclusions 524 Additional reading 525

5 Cancer 529 M. Rock 5.1 Introduction 529 5.2 Release and distribution of degradation products 530 5.3 Neoplasia 531 5.4 Evidence for carcinogenicity of implanted

materials 532 5.5 Case reports of implant related tumors 533 5.6 Critical analysis of tumors 536 5.7 Significance of clinical reports 538 5.8 Summary 539 Additional reading 540 References 541

xii I I CONTENTS

6 Blood-material interactions 545 S.R. Hanson 6.1 Introduction 545 6.2 Experimental difficulties 545 6.3 Conventional polymers 548 6.4 Hydrophylic polymers 548 6.5 Metals 549 6.6 Carbons 550 6.7 Ultra-thin film coatings 550 6.8 Membranes 550 6.9 Biological surfaces 551 6.10 Surface texture 551 6.11 Conclusion 552 Additional reading 552 References 553

7 Soft tissue response to silicones 556 S. E. Gabriel 7.1 Silicones used in medicine 556 7.2 Local immunologic reactions to silicone 556 7.3 Systemic immunologic reactions to silicone 557 7.4 Evidence for causation 559 7.5 Controlled studies examining the relationship between

breast implants and connective tissue disease 563 References 567

Index 573

Foreword

Progress in the development of surgical implant materials has been hindered by the lack of basic information on the nature of the tissues, organs and systems being repaired or replaced. Materials' properties of living systems, whose study has been conducted largely under the rubric of tissue mechanics, has tended to be more descriptive than quantitative. In the early days of the modern surgical implant era, this deficiency was not critical. However, as implants continue to improve and both longer service life and higher reliability are sought, the inability to predict the behavior of implanted manufactured materials has revealed the relative lack of knowledge of the materials properties of the supporting or host system, either in health or disease. Such a situation is unacceptable in more conventional engineering practice: the success of new designs for aeronautical and marine applications depends exquisitely upon a detailed, disciplined and quantitative knowledge of service environments, including the properties of materials which will be encountered and interacted with. Thus the knowledge of the myriad physical properties of ocean ice makes possible the design and development of icebreakers without the need for trial and error. In contrast, the development period for a new surgical implant, incorporating new materials, may well exceed a decade and even then only short term performance predictions can be made.

Is it possible to construct an adequate data base of materials proper­ties of both manufactured materials and biological tissues and fluids such that in vitro simulations can be used to validate future implant designs before in vivo service? While there are no apparent intellectual barriers to attaining such a goal, it clearly lies in the distant future, given the complexity of possible interactions between manufactured materials and living systems.

However, a great body of data has accumulated concerning the mate­rials aspects of both implantable materials and natural tissues and fluids. Unfortunately, these data are broadly distributed in many forms of publi­cation and have been gained from experimental observations of varying degrees of accuracy and precision. This is a situation very similar to that

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in general engineering in the early phases of the Industrial Revolution. The response then was the publication of engineering handbooks, drawing together, first in general publications and later in specialty versions, the known and accepted data of the time. In this spirit, we offer this Handbook of Biomaterial Properties.

Biomaterials, as manufactured for use in implants, do not exist usefully out of context with their applications. Thus, a material satisfactory in one application can be wholly unsuccessful in another. In this spirit, the Editors have given direction to the experts responsible for each part of this Handbook to consider not merely the intrinsic and interactive properties of biomaterials but also their appropriate (and in some cases inappro­priate) applications as well as their historical context. It is hoped that the results will prove valuable, although in different ways, to the student, the researcher, the engineer and the practicing physician who uses implants.

A handbook like this necessarily becomes incomplete immediately upon publication, since it will be seen to contain errors of both omission and commission. Such has been the case with previous engineering handbooks: the problem can only be dealt with by providing new, revised editions. The Editors would appreciate any contributions and/or criticisms which the users of this handbook may make and promise to take account of them in future revisions.

Introduction

It is a feature of any developing science and its accompanying technology that information relating to different aspects is scattered throughout the relevant, and sometimes not so relevant literature. As the subject becomes more mature, a body of information can be categorized and brought together for the use of practitioners. In providing this Handbook of Biomaterial Properties the Editors believe that the latter stage has been reached in several parts of the vast field of biomaterials science and engi­neering.

Many of the properties of the synthetic materials have been available for some time, for example those of the various metallic alloys used in clinical practice have been specified in various International, European and National Standards and can be found by searching. In the case of polymeric materials, while the information is in commercial product liter­ature and various proprietary handbooks, it is diverse by the nature of the wide range of materials commercially available and the search for it can be time consuming. The situation is much the same for ceramic and composite materials: there the challenge is finding the appropriate prop­erties for the specific compositions and grades in use as biomaterials.

However, when information is sought for on materials properties of human tissues, the problem is more acute as such data are even more scattered and the methods for determination are not always stated or clearly defined. For the established worker this presents a major task. For the new researcher it may make establishing a project area a needlessly time consuming activity. The biomaterials bulletin boards (on the Internet) frequently display requests for help in finding characterization methods and/or reliable properties of natural materials, and sometimes the infor­mation is actually not available. Even when it is available, the original source of it is not always generally known.

In approaching their task, the Editors have tried to bring together into one source book the information that is available. To do this they have asked for the help of many colleagues worldwide to be contributors to the Handbook. It has not been possible to cover all the areas the Editors

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had hoped. Some topics could not be covered, or the information was judged to be too fragmentary or unreliable to make it worth including. This is inevitably the sort of project that will continue to be incomplete; however, new information will be provided as more experiments are done and as methods for measurement and analysis improve. The aim has been to make this Handbook a ready reference which will be consulted regu­larly by every technician, engineer and research worker in the fields of biomaterials and medical devices.

We have tried, not always successfully, to keep the textual content to a minimum, and emphasize tabular presentation of data. However, in some cases it has been decided to include more text in order to establish the background of materials properties and use and to point to critical features in processing or production which would guide the worker looking for new applications or new materials. For example, in polymer processing, the need to dry materials thoroughly before fabrication may not be under­stood by those less well versed in production techniques.

It is hoped that the Handbook will be used and useful, not perfect but a valuable contribution to a field that we believe has matured sufficiently to merit such a pUblication. The Handbook is divided into synthetic and natural materials and the treatment is different in each part. More back­ground was felt to be needed for the synthetic materials since processing and structural variations have a profound effect on properties and perfor­mance. Biological performance of these materials depends on a range of chemical, physical and engineering properties and the physical form can also influence in vivo behavior. We have not attempted to deal with issues of biological performance, or biocompatibility, but have dealt with those other features of the materials which were felt to be relevant to them as potential biomaterials. Only materials having apparent clinical applica­tions have been included.

The biological materials have more dynamic properties since, in vivo, they respond to physiological stimuli and may develop modified proper­ties accordingly. The treatment of their properties has been limited to those determined by well characterized methods for human tissues, with a few exceptions where data on other species is deemed to be applicable and reliable. These properties determined almost totally in vitro may not be directly predictive of the performance of the living materials in vivo, but are a guide to the medical device designer who wishes to deter­mine a device design specification. Such a designer often finds it hard to realize the complexity of the task of dealing with a non-engineering system. What really are the parameters needed in order to design an effec­tively functioning joint endoprosthesis or a heart valve? Do tissue properties measured post explantation assist? Is individual patient lifestyle an important factor? There is immediately a degree of uncertainty in such design processes, and total reliability in performance cannot be given a

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prospective guarantee. However, the more we learn about the materials and systems of the human body and their interaction with synthetic bioma­terials, the closer we may perhaps become to the ideal 'menotic' or forgotten implant which remains in 'menosis' - close and settled union from the Greek J..LEVW - with the tissues in which it has been placed.

Three final comments: Although the Editors and contributors frequently refer to synthetic and,

in some cases, processed natural materials as 'biomaterials,' nothing herein should be taken as either an implied or explicit warrantee of the useful­ness, safety or efficacy of any material or any grade or variation of any material in any medical device or surgical implant. Such determinations are an intrinsic part of the design, development, manufacture and clinical evaluation process for any device. Rather, the materials listed here should be considered, on the basis of their intrinsic properties and, in many cases, prior use, to be candidates to serve as biomaterials: possibly to become parts of successful devices to evaluate, direct, supplement, or replace the functions of living tissues.

The Editors earlier refer to absences of topics and of data for partic­ular synthetic or natural materials. While this may be viewed, perhaps by reviewers and users alike, as a shortcoming of the Handbook, we view it as a virtue for two reasons:

• Where reliable data are available but were overlooked in this edition, we hope that potential contributors will come forward to volunteer their help for hoped for subsequent editions.

• Where reliable data are not available, we hope that their absence will prove both a guide and a stimulus for future investigators in bioma­terials science and engineering.

The Editors, of course, welcome any comments and constructive criti­cism.

Professor Garth W. Hastings Institute of Materials Research & Engineering - IMRE, Block S7, Level 3, Room 17B, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260. Tel: +65 771 5249 Fax: +65 872 5373

Professor Emeritus Jonathan Black Principal: IMN Biomaterials 409 Dorothy Drive King of Prussia, PA 19406-2004, USA TelfFax: +1 610 265 6536

JB GWH

Contributors

COMMISSIONED BY J. BLACK:

T.O. Albrektsson University of Gothenburg Handicap Research, Institute for Surgical Sciences Medicinaregatan 8 Gothenburg S-413 90, Sweden

J .M. Anderson University Hospitals of Cleveland Department of Pathology Case Western Reserve University 2074 Abington Road Cleveland, OH 44106-2622, USA

T.V. Chirila Lions Eye Institute 2 Verdun Street, Block A, 2nd Floor Nedlands, W. Australia 6009

Professor J.D. Currey Department of Biology York University York YOl 5DD, United Kingdom

X. Deng Laboratorie de Chirugie Exp Agriculture Services Room 1701 Services Building Universite Laval Quebec G 1K 7P4, Canada

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S.E. Gabriel Division of Rheumatology Mayo Clinic 200 First Street Southwest Rochester, MN 55905, USA

V.M. Gharpuray Department of Bioengineering 401 Rhodes Eng. Res. Ctr. Clemson University Clemson, SC 29634-0905, USA

R. Guidoin Laboratorie de Chirugie Exp Agriculture Services Room 1701 Services Building Universite Laval Quebec G1K 7P4, Canada

S.R. Hanson Division of Hematology/Oncology PO Box AJ Emory University Atlanta, GA 30322, USA

K.E. Healy Department of Biological Materials Northwestern University 311 E. Chicago Ave. Chicago, IL 60611-3008, USA

Y. Hong Lions Eye Institute 2 Verdun Street, Block A, 2nd Floor Nedlands, W. Australia 6009

T.M. Keaveny Department of Mechanical Engineering Etcheverry Hall University of California at Berkeley Berkeley, CA 94720, USA

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R.E. Levine Musculoskeletal Research Centre University of Pittsburgh 1011 Liliane S. Kaufmann Building 3741 Fifth Avenue Pittsburgh PA 15213, USA

Arthur K.T. Mak Rehabilitation Engineering Centre Hong Kong Polytechnic Hunghom, Kowloon, Hong Kong

S.S. Margules Department of Bioengineering 105D Hayden Hall University of Pennsylvania Philadelphia, PA 19104-6392, USA

D.F. Meaney Department of Bioengineering 105E Hayden Hall University of Pennsylvania Philadelphia, PA 19104-6392, USA

K. Merritt 17704 Stoneridge Dr. Gaithersburg, MD 20878, USA

Professor J.R. Parsons Orthopaedics-UMDNJ 185 South Orange A venue University Heights Newark, NJ 07103-2714, USA

M.G. Rock Department of Orthopaedics Mayo Clinic 200 First Street Southwest Rochester, MN 55905, USA

S.M. Slack Department of Biomedical Engineering University of Memphis, Campus Box 526582, Memphis, TN 38152-6502, USA

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v. Turitto Department of Biomedical Engineering University of Memphis Memphis, TN 38152, USA

Professor D.F. Williams Department of Clinical Engineering Royal Liverpool University Hospital PO Box 147 Liverpool L69 3BX, United Kingdom

S.L.-Y. Woo Musculoskeletal Research Center University of Pittsburgh 1011 Liliane S. Kaufmann Building 3741 Fifth Avenue Pittsburgh, PA 15213, USA

M. Zhang Rehabilitation Engineering Centre Hong Kong Polytechnic Hungham, Kowloon, Hong Kong

COMMISSIONED BY G.W. HASTINGS:

L. Ambrosio Department of Materials and Production Engineering University of Naples Federico II Institute of Composite Materials Technology CNR Piazzale Techio, 80 80125 Naples, Italy

M.A. Barbosa INEB-Ma Rua do Campo Alegre 823 4150 Porto, Portugal

V. Biehl Lehrstuhl fOr Metallische Werkstoff Universitat des Saarlandes Saarbriicken, Germany

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J.e. Bokros Medical Carbon Research Institute 8200 Cameron Road Suite A-196 Austin TX 78754-8323, USA

J.W. and S.J. Boretos Consultants for Biomaterials 6 Drake Court Rockville Maryland 20853, USA

H. Breme Lehrstuhl fUr Metallische Werkstoffe Universitat des Saarlandes Saarbriicken, Germany

G. Carotenuto Department of Materials and Production Engineering University of Naples Federico II Institute of Composite Materials Technology CNR Piazzale Technio, 80 80125 Naples, Italy

A.D. Haubold Medical Carbon Research Institute 8200 Cameron Road Suite A-196 Austin TX 78754-8323, USA

L. Hench Imperial College Department of Materials Prince Consort Road London SW7 2BP, United Kingdom

T. Kookubo Division of Material Chemistry Faculty of Engineering Kyoto University, Sakyo-ku, Kyoto 606-01, Japan

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M. LaBerge Associate Professor School of Chemical and Materials Engineering 401 Rhodes Research Center Clemson University, Clemson, SC 29634-0905, USA

P.J. Li Centre for Oral Biology Karolinska Institute Huddinge S 141-4, Sweden

R.B. More Medical Carbon Research Institute 8200 Cameron Road Suite A-196 Austin TX 78754-8323, USA

L. Nicolais Department of Materials and Production Engineering University of Naples Federico II Institute of Composite Materials Technology CNR Piazzale Technio, 80 80125 Naples, Italy

H. Oomamiuda Department of Orthapaedic Surgery Artificial Joint Section and Biomaterial Research Laboratory Osaka-Minami National Hospital 677-2 Kido-Cho, Kawachinagano-shi, Osaja, Japan

H.Oonishi Department of Orthopaedic Surgery Artificial Joint Section and Biomaterial Research Laboratory Osaka-Minami National Hospital 677-2 Kido-Cho, Kawachinagano-shi, Osaka, Japan

Z.G. Tang BIOMAT Centre National University of Singapore Singapore 119260

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S.H. Teoh Institute of Materials Research & Engineering - IMRE Block S7, Level 3, Room 17B National University of Singapore 10 Kent Ridge Crescent Singapore 119260