Surface Engineering and Technology for Biomedical Implants

YOSHIKI OSHIDA

MOMENTUM PRESS, LLC, NEW YORK

Surface Engineering and Technology for Biomedical ImplantsCopyright © Momentum Press®, LLC, 2014

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, photocopy, recording or any other—except for brief quotations, not to exceed 400 words, without the prior permission of the publisher.

First published by Momentum Press®, LLC222 East 46th Street New York, NY 10017www.momentumpress.net

ISBN-13: 978-1-60650-627-1 (hard back, case bound)ISBN-13: 978-1-60650-628-8 (e-book)DOI: 10.5643/9781606506288

Cover design by Jonathan PennellInterior design by Exeter Premedia Services Private Ltd.,Chennai, India

10 9 8 7 6 5 4 3 2 1

Printed in the United States of America

To my wifefor putting up with me

&To my parents and family members

for their love, support, and encouragement

vii

Contents

Preface xi

Acknowledgements xiii

Prologue xv

Chapter 1 Introduction 1

1.1 Literature Review Results 11.2 Acceptability and Prevalence of Implants 21.3 Overview of Implant Technology 3

References 5

Chapter 2 Implantable Materials 7

2.1 Introduction 72.2 Metallic Biomaterials 82.3 Polymeric Biomaterials 122.4 Ceramic Biomaterials 132.5 Composites 14

References 15

Chapter 3 Interfacial Reactions Between Vital Tissue and Nonvital Implant Surfaces 21

3.1 Introduction 213.2 Toxicity 24

3.2.1 Chemical Toxicity 253.2.2 Biological Toxicity 263.2.3 Physical Toxicity 27

3.3 Allergic Reaction 283.4 Compatibility 30

3.4.1 Hemocompatibility 313.4.2 Cytocompatibility 32

viii • Contents

3.5 Bone Healing 363.5.1 Cellular Response to Biomaterials 373.5.2 Cell Attachment, Adhesion, and Spreading 393.5.3 Cell Proliferation and Differentiation 473.5.4 Bone Ingrowth 543.5.5 Bone Healing and Grafting 613.5.6 Osseointegration 64

3.6 Loosening Implants and Infection 70

References 71

Chapter 4 Requirements for Successful Implant Systems 93

4.1 Introduction 934.2 Biological Compatibility 944.3 Biomechanical Compatibility 994.4 Morphological Compatibility 106

References 111

Chapter 5 Surface Modification 121

5.1 Introduction 1215.2 Nature of Surface and Interface 1225.3 SurfaceModificationTechnologies 122

5.3.1 MechanicalModification 1235.3.2 ChemicalandElectrochemicalModifications 1285.3.3 PhysicalModification 1345.3.4 ThermalModification 1455.3.5 Combined Technology 147

5.4 Coating Materials and Materials Preparation 1505.4.1 Metallic Materials 1505.4.2 Polymeric Materials 1535.4.3 Ceramics—Metallic Oxides, Nitrides, and Carbides 1535.4.4 Ceramcis—Nonmetallic Compounds 1585.4.5 Composites, Hybrids, Functional Gradient Materials, and

Biomimetic Materials 1625.4.6 Others 165

References 166

Chapter 6 Evaluation and Characterization of Modified Surfaces 201

6.1 Introduction 2016.2 Safety Concerns and Testing 2026.3 Magnetic Resonance Imaging Safety and Image Compatibility 203

Contents • ix

6.4 Hydrophilicity and Hydrophobicity 2056.5 Blood Compatibility 2076.6 Cell Adhesion and Adhesive Strength 2086.7 Osseointegration 2116.8 Biomimetic Coating 2156.9 Measures Against Toxic Ion Elution 2176.10 Evaluation of Biocompatibility 2176.11 Mechanical Properties 2186.12 Temperature Changes 2216.13 Corrosion Behavior 2216.14 Effect of Sterilization 2236.15 Strontium Effect 2246.16 Characterization of HA 2246.17 Characterization of Other Bio-Ceramics 2276.18 Surface Texturing and Topology 2306.19 Retrieved Implants 237

References 240

Chapter 7 New Materials, New Structures, and New Technologies 261

7.1 Introduction 2617.2 New Materials 262

7.2.1 Bone Materials 2627.2.2 Porous Materials 2647.2.3 Nanomaterials 2657.2.4 Functionally Gradient Materials 270

7.3 New Structures 2717.3.1 Nanostructures 2717.3.2 Biomimetic Functionalization 275

7.4 New Technologies 2777.4.1 Tissue Engineering 2777.4.2 Three-Dimensional Printing 2787.4.3 Laser Technologies 2787.4.4 Electrospinning 2807.4.5 Atmospheric Plasma Treatment 2817.4.6 Friction Stir Welding 2817.4.7 Near-Net Shape (NNS) Forming 2817.4.8 Miscellaneous 282

References 286

Index 293

xi

Preface

As society is increasingly concerned with quality of life for an ever-growing elderly population and those with sports and military injuries, greater attention is being paid to managing diseases and pains, as well as treating these populations. Orthopedics and dental implants still face many challenges to facilitate the aged society, in par-ticular, because implant receiving vital hard tissue gradually deteriorates (in the sense of reduced bone density and quality). In addition, special developments in materials, as well as treatment techniques, are urgently needed for dental/medical implant can-didates who have already developed serious or lifestyle-related diseases which are contraindicative to implant treatments.

And there is much development going on. As detailed in the Prologue and Chapter 1, there are no fewer than 120 journals in the medical/dental and engineering fields related to the subject in this book. The challenges are interdisciplinary and of world-wide interest.

Chapters 2 through 4 discuss materials and compatibility requirements. Well-established treatments are discussed in Chapter 5, followed by evaluations in Chapter 6. But there are still many materials, modification methods, as well as treatment tech-niques, which are under R&D stage, as seen in Chapter 7. These should include an extensive application of 3D bioprinting technology toward a successful fabrication of customized implant systems, functionally gradient material/structure, biofunctional-ization of newly developed materials, and so forth.

Keywords

surface, interface, surface engineering and modification, biomaterials, implantable materials, compatibilities

xiii

Acknowledgements

In closing, I admit to having a very long list of individual names to be mentioned with my memories and appreciation–from my teachers who inspired me, friends and col-leagues who challenged me, and most importantly students (some of them are now my colleagues) who continue to both inspire and challenge me. To all of them, I owe my knowledge and capability to comprehend the cited articles presented in this book. These people, who were and are valuable to me and to this book, should at least include the late T. Nakayama, S. Iguchi, V. Weiss, H. W. Liu, the late J. A. Schwartz, T. Koizumi, N. Saotome, T. Nishihara, F. Farzin-Nia, G. K. Stookey, the late C. J. Andres, the late T. M. Barco, M. Kowolik, V. John, D. Brown, D. Burr, M. Siefert, R. Shew, J. A. Parr, R. Miyamoto, M. Kingsley, J. Williams, J. Levon, A. Zuccari, A. Hashem, A. Wu, M. Yapchulay, S. Isikbay, C. Kuphasuk, C-M. Lin, I. Garcia, W. Panyayong, Y-J.Lim, M.Reyes, W. C. Lim, J-C. Chang, S. Al-Ali, B. Anbari, D. Bartovic, F. Hernandez, I. W. Koh, Z. H. Khabbaz, R. Xirouchaki, P. Agarwal, N. Al-Nasr, C. B. Sellers, J. Dunigan-Miler, S. Al-Johancy, C. S. Wang, E. Matsis, R. Rani, Y-C. Wu, K. Mirza, I. Katsilieri, C. N. Elias, E. B. Tuna, O. Aktören, K. Gençay, Y. Güven, L. Oshida, and JIP (Japan Implant Practice) Association members. Special thanks should also go to M. A. Dirlam for excellent professional illustrations of all figures in this book, and to the Editorial team at Momentum Press (S. Goldberg, J. Stein, and M. Treloar). Finally, but not least important, special thanks should go to J. Schulterbrandt for his comments on the text. Thank you all.

xv

Prologue

This book is based on a review of about 1,500 carefully selected articles and presents itself as a typical example of evidence-based learning (EBL). Evidence-based litera-ture reviews can provide foundation skills in research-oriented bibliographic inquiry, with an emphasis on such review and synthesis of applicable literature. Information is gathered by surveying a broad array of multidisciplinary research publications written by scholars and researchers.

In order for EBL to be used effectively, the content of every publication must be critically evaluated in terms of its degree of reliability. There is an established protocol for ranking the reliability of sources—this is a especially useful tool in the medical and dental fields. The ranking, from the most to least reliable evidence source, fol-lows: (i) clinical reports using placebo and double blind studies, (ii) clinical reports not using placebo, but conducted according to well-prepared statistical test plans, (iii) study reports on time-effect on one group of patients during predetermined period of time, (iv) study/comparison reports, at one limited time, on many groups of patients, (v) case reports on a new technique or idea, or both, and (vi) retrospective reports on clinical evi-dence. Unfortunately, the number of published articles increases in this descending reli-ability order. The greatest advantage of the EBL review is that it helps identify common phenomena in a diversity of fields and literature. It is then possible to create synthetic, inclusive hypotheses that deepen and further our understanding.

As important as the diversity of source material is to the EBL review, it can pose unique challenges. The sources used in this review are mainly journal articles pub-lished in the medical/dental and engineering fields. These two groups’ studies have very different analytical criteria and inherent issues.

In medical/dental journals authors typically present statistically analyzed results; this lends these studies a high degree of reliability. Though we may be confident in the conclusions drawn from statistical analysis, it can be difficult to develop generalized ideas from this literature. Some controversy exists in the medical and dental fields on the relationship between in vitro and in vivo test results. This situation is further com-plicated and confusing because among the various in vivo tests exists a wide variety of animal model species. The in vitro studies are also not without weakness—it is almost impossible to broadly extrapolate in vitro test results, since it is very rare to find articles where identical test methods were employed.

In contrast to medical/dental studies, the data presented in the engineering jour-nals are normally not subjected to statistical analysis. The characterization of data is

xvi • Prologue

considered more important to interpretation results because researchers try to explain phenomena, mechanisms, and kinetics.

Discoveries in the engineering realm are vitally important to the advancement of medicine and dentistry: the materials and most of the technologies currently employed in medical and dental fields were originally developed in the engineering field. In this book, the author draws upon his unique experience in both fields to bridge the gap between medical/dental and engineering research.

At the early stages of preparing this book, the author chose appropriate journals in both medical/dental and engineering fields, which were directly and indirectly rel-evant to a group of key words including: surface, interface, surface engineering and modification, biomaterials, implantable materials, and compatibilities. There are about 120 journals in front of me. These are surprisingly a large number of journals. For those who might be interested in the literature survey in similar scope of this book, here is a lengthy list of journals; Am J Orthod, Am J Dent, Angle Orthod, Advanced Material Process, American J Orthod Dentofacial Orthop, ASM Intl, Apply Sur Sci, Advances Dent Res, Amer J Orthod, Acta Biomater, Ann Biomed Eng, Appl Sur Sci, ACS Nano, Adv Orthop Surg, Biomaterials, Br Med J, Bone Joint Surg Br, Biomed Mater, Bioelectrochemistry, Biochemistry, CRC Crit Rev Biocompatibility, Cell Clin Implant Dent Relat Res, Clin Orthop, Clin Oral Implant Res, Clin Oral Investing, Clin Mater, Contact Dermatitis, Crit Rev Oral Boil Med, Corr Sci, Corrosion, Colloids Surf B Biointerfaces, Dent Mater J, Digest J Nanometer and Biostructures, Electrochem Acta, Faraday Discuss, Gen Dent, Intl Dental Jour, Int J Oral Maxillofac Implants, Int J Oral Surg, Int J Nanomed, Int J Prosthodont, Implant Dent, Int Arch Allergy Apply, Immunol, Int J Mol Sci, J Adhes, J Adhes Sci Technol, J Alloys Compound, J Am Ceram Soc, J Appl Phys, J Apply Biomater, J Assoc Ad Med Instrum, J Arthroplasty, J Bacterial J Biochem Biophys Method, J Biosci Polym Ed, Journal of Metals, J Biomech, J Biomed Mater Res A, J Biomed Mater Res B, J Bio-Med Mater Eng, J Bone Joint Surg Am, J Bone Miner Res, J Cardiovasc Technol, J Chronic Dis, J Clin Invest, J Clin Pathol, J Colloid Interface Sci, J Dent Res, J Electroceramics, J EngTribol, J Exp Med, J Invest Dermatol, J Jpn Soc Dental Mater Devices, J Less-Common Metal, J Mater Sci, J Mater Sci Let, J Mater Process Technol, J Mech Behav Biomed Mater, J Mater Sci Mater Med, J Nanosci Nanotechnol, J Prosthet Dent, J Electrochem Soc, J Oral Implants, J Oral Rehabil, J Prosthodont, J Vac Sci Technol, Jpn Inst Metals, Jpn Dent Mater, Langmuir, Metall Mater Trans A, Metall Mater Trans B, Mater Manufac Process, Mater Science Eng A, Mater Science Eng B, Mater Perform, Mater Science Forum, Mol Biology of the Cell, Med Device Technol, Med Sci Monit, Med Prog Technol, Orthopedics, Oral Microbial Immunol, Proc Royal Soc, Prog Organ Coat, Quint Intl, Quint Dent Technol, Surf Coat Technol, Surf Technol, Surf Interface Anal, Tribology Industry, Tissue Eng, Tribol Letter, The Amer Soc Metals, Trans Orthop Res Soc, Trans Soc Biomater, Trans Electrochem Soc, Thin Solid Films, Toxicology, and Wear. I suspect there should be more than these.

Let’s do a simple calculation, suppose each journal is published monthly (of course, some of these are published quarterly). Looking only at the last 10 years, it might be simply 120 journals × 12 months × 10 years = 14,400 individual journals. Of course, all of these articles are not equally relevant to the scope of this book; let us assume

Prologue • xvii

that approximately 10% of these should possess reasonable relevancy to this book. As I mentioned in the prologue, I carefully selected about 1,500 articles, which is about 10% of the aforementioned number. In other words, at least one article out of the 120 journals published monthly is somewhat related to this book. Accordingly, the contents of this book should well-represent worldwide researches.

1

Chapter 1

Introduction

We have a tremendous number of artificial organs or devices that help to maintain patients’ quality of life (QOL); they include hydrocephalus shunts, ocular and contact lenses, orbital floors, artificial ears, cochlear implants, nasal implants, artificial chins, mandibular mesh, artificial skin, blood substitutes, artificial hearts and heart valves, pacemakers, breast prostheses, pectus implants, glucose biosensors, dialysis shunts and catheters, absorbable pins, temporary tendons, artificial kidneys, birth control implants, vascular grafts, artificial live, spinal fixations, finger joints, cartilage replacements, artificial legs, bone plates and bars (including sacroiliac joint), and Harington spinal bars. There are also a variety of dental prostheses, including dental implants, bridges and crowns, endodontic devices, orthodonticarch wires, and brackets. The develop-ment of dental and orthopedic implants (particularly, knee, and total hip replacements) is particularly important and the most challenging, because it involves the collective knowledge and synthesis of several diverse disciplines such as biomaterials science and engineering, and surface modification and technology in order to obtain its ulti-mate goal: That their surfaces are biologically accepted by a host’s vital hard and soft tissues and function in body.

This chapter introduces the three basic requirements for placed implants to exhibit satisfactory biofunctionality: Biological (or in short, biocompatibility), morphologi-cal, and biomechanical compatibility. In the following chapters of this book, we will discuss implantable materials, the nature of surfaces and interfaces, some important interfacial reactions, requirements for successful implant systems, and surface modifi-cations and its methods, characterization, and evaluations of modified surfaces. At the end, we will introduce the application of newly developed technology into dental and medical implantology.

1.1. Literature Review Results

Figure 1.1 shows the popularity of pure titanium (CpTi: commercially pure titanium) and its alloys (typically, Ti–6Al–4V and Ti–6Al–7Nb) in dental and medical fields by counting the manuscripts published in different journals, most of which will be cited in this book, and the number of publication on the term “biocompatibility” [1,2]. Referring

DOI 10.5643/9781606506288/ch1

2 • Surface Engineering and Technology for Biomedical Implants

to the figure, there are three straight lines in the semi-log plot that demonstrate the total accumulated number of published articles every 5 years. The uppermost line represents the accumulated number of all articles listed in Chemical Abstract. It represents a wide scattering of articles in many areas including refining, metallurgy, dentistry, medicine, bioengineering, engineering, industries, pure chemistry, and chemical engineering. The second straight line from the top is obtained when the search area is limited to materials science in both the engineering and medical/dentistry fields. If our search is further defined within only medicine/dentistry area, we still have an exponential increase in publications. If we search only for articles related to “biocompatibility,” the number of published articles by year again appears to be increasing almost in parallel to those on titanium biomaterials in dentistry and medicine, indicating that the concept of biocompatibility is recognized as very important when biomaterials are used for both dental (intraoral) and orthopedic (extraoral) implant systems.

1.2. Acceptability and Prevalence of Implants

A questionnaire yielded interesting results about the differences in attitudes toward implant treatment among middle-aged and older Swedish subjects over a 10-year

Figure 1.1. Accumulated number of published articles on titanium materials and biocompatibility.

1960100

1,000

2

3

456789

10,000

2

3

456789

100,000

2

3

456789

2

1965 1970 1975 1980 1985

Year

1990 1995 2000 2005 2010

Th

e n

um

ber

of

pu

blis

hed

art

icle

sChemical abstract

Material science and engineering

Density and medicine

Biocompatibility

Introduction • 3

interval in 1989 and 1999 [3]. One thousand six hundred sixty-five subjects responded to both surveys. It was reported that (i) in 1989, few respondents indicated an interest in implant treatment, (ii) whereas, in 1999, 92% of those who had not indicated an interest in the earlier survey now indicated that they desired implant treatment, and (iii) changes in awareness of implant treatment, along with an expansion in the number of qualified providers, may have contributed to this increase [3]. Advances in medical science and developments in biomedical materials have led to a remarkable increase in life span and improvement of QOL. Monitoring friction and wear in the human body has played a very significant role in those improvements.

There are six major joint systems in our body: the shoulder, elbow, wrist, hip, knee, and ankle joints. Replacement surgery is commonly performed on hip and knee joints. Hip prosthesis or hip replacement surgery becomes necessary when the hip joint has been badly damaged from causes such as arthritis, congenital malformation or abnor-mal development, and damage from injury. A natural hip is composed of a femoral (thigh bone) with a femoral head on top of it that articulates with the acetabular cup in the acetabulum. As in all other joints, cartilage is found between the acetabular cup and the femoral head, and acts to lubricate their movement and facilitate the articula-tion. In an arthritic hip joint, the cartilage has been damaged, narrowed or even lost by a degenerative process or by inflammation.

Thus, several organs, joints, and critical parts of the human body wear out and may be replaced [4]. According to a report, the amount of predicted implant placements in 2002 in the United States will be as follows: total hip joint replacements: 448,000; knee joint replacements: 452,000; shoulder joint replacements: 24,000; dental implants: 854,000; coronary stents: 1,204,000; and coronary catheters: 1,328,000 [5,6]. Further, even when the implantation has been successfully performed and the prognosis has been excellent, dental and medical implants can fail due to wear, fatigue, chemical degradation, infection, and lead to osteolysis and loosening [4,7].

1.3. Overview of Implant Technology

In order to place an implantable material, the host’s hard tissue has to be traumatized. Injured or diseased tissues will be removed to some extent in the process of implan-tation. The success of the entire operation depends on the kind and degree of tissue response (biocompatibility) toward the implants during the healing process. The tissue response toward the injury may vary widely according to the site, species, contamina-tion, and so forth [5,7].

Endosseous dental implants have created a revolution in the routine approach to dental care for patients missing one or more teeth. The success of this procedure was obtained through a series of clinical and biological steps, starting with the initial pri-mary stability provided by the amount, quality, and distribution of bone within the proposed implant site [8–10]. Following the placement of the dental implant, a series of bone modeling and remodeling steps take place. Bone adaptation or integration of an implant is characterized by a series of biological reactions that start with bone turnover at the interface: a process of localized necrosis, followed by rapid repair [11]. The long-term success of implant therapy is not just dependent on enhanced osseous

4 • Surface Engineering and Technology for Biomedical Implants

stability, greater attention being given to the transmucosal dental implant or implant abutment interfaces. The mechanical and biological stability derived from the design and surfaces in this connective tissue and adjacent epithelial environment are critical to maintaining a sufficient volume of connective tissue with minimal inflammatory infiltrate [12]. In order to increase the predictability of implant therapy, significant efforts have gone into the development of implant biomaterials that hold the promise of improving clinical success. These technologies have evolved from simple modification of the oxide surface to precise nanoscale modification technologies that involve the formation of a uniform and consistent surface that leads to altered cellular response. Further, there are developing technologies that utilize changes in surface chemistry. Also, biologics are also being added to the oxide surface in order to assist in stability of both the osseous and transmucosal environment [12–16].

With regard to bone healing immediately after placing an implant(s) in trauma-tized bone, there are three distinct and crucial stages: (i) the first and most important healing phase, osteoconduction, relies on the recruitment and migration of osteogenic cells to the implant surface, through the residue of the peri-implant blood clot. Among the most important aspects of osteoconduction are the indirect effects generated at the implant surface, by the initiation of platelet activation, which results in directed osteo-genic cell migration, (ii) the second healing phase, de novo bone formation, results in a mineralized interfacial matrix equivalent to that seen in the cement line in natural bone tissue; these two healing phases, osteoconduction and de novo bone formation, result in contact osteogenesis and, given an appropriate implant surface, bone bonding, and (iii) the third healing phase, bone remodeling, relies on slower processes [17,18].

Osseointegration, which can be defined as a direct structural and functional connec-tion between living bone and the surface of a load-carrying implant and is recognized as a time-depending bone healing, is critical for implant stability, and is considered a prerequisite for implant loading and long-term clinical success of endosseous dental implants. The implant/tissue interface is an extremely dynamic region of interaction. This complex interaction involves not only biomaterial and biocompatibility issues but also alteration of mechanical environment. The processes of osseointegration involve an initial interlocking between alveolar bone and the implant body, and later, biological fixation through continuous bone apposition and remodeling toward the implant. The process itself is quite complex and there are many factors that influence the formation and maintenance of bone at the implant surface. Ideally, an implant’s appearance can histologically resemble a functional ankylosis, with no intervention of fibrous or con-nective tissue between bone and implant surface [19,20]. The successful outcome of any implant procedure is mainly dependent on the interrelationship of the various fac-tors, including biocompatibility of the implant material, macroscopic and microscopic nature of the implant surface and designs, the status of the implant in both a health and a morphology (bone quality) context, the surgical technique, the health of the patient, the undisturbed healing phase, and loading conditions [19,21].

Various modifications of the implant surface can alter the percentage of osseoin-tegration. New types of reinforcements for implants and the use of growth factors to augment bone regeneration have been developed [17]. As mentioned before, osseo-integration is a major factor influencing the success of dental implants. To achieve rapid and strong durable osseointegration, biomaterial researchers have investigated

Introduction • 5

various surface treatment methods, particularly for titanium dental implants. Current dental implant research has studied the interaction between bone and implant surfaces in order to understand and improve the osseointegration process. The implant surface treatment, chemical or topographic modification, and cellular interactions can affect bone healing, promote accelerated osteogenesis, and increase bone–implant contact and bond strength.

Surface characteristics determine not only aesthetic appearance but also interac-tion with the environment, including mechanical interactions such as friction and wear and chemical interactions such as adherence and biocorrosion. Coatings, claddings, thin films, and other surface modifications may be categorized in many ways. One of these is principally by the form of the material deposited at any given instant on a small area of the surface. Such forms include atoms or molecules, particles, bulk, and others. Atomic deposition include electroplating, CVD (chemical vapor deposition), PVD (physical vapor deposition), ion implantation, vacuum evaporation, molecular beam epitaxy, plasma and sputter deposition, and spray pyrolysis. Particulate deposi-tion includes thermal spray, flame spray, high velocity oxyfuel spray, impact packing, fusion coating, enameling, and electrophoresis. Bulk coating/cladding should include wetting processes such as painting and dip coating, electrostatic spraying such as spin coating, laser cladding, and high temperature synthesis. In addition to these, shot peen-ing and laser peening can be included as mechanical modification [22,23]. Surface transformations (such as ceramization, nitrization, etc.) can be performed on metals in order to combine their load-bearing properties to the inertness and wear resistance of ceramics. In a joint prosthesis, metals are useful for their high fatigue strength and ductility, but they are more sensitive to superficial corrosion and wear than ceram-ics. Coating a ceramic on metal surface will improve the qualities of the metallic component [24].

References1. Oshida, Y., 2007, Bioscience and Bioengineering of Titanium Materials, Elsevier, London,

UK, pp.4–5.2. Annual number of published articles in peer-review journals on “Biocompatibility”

between 1970 and 2007. en.wikipedia.org/wiki/Biocompatibility.3. Narby, B., Kronström, M., Söderfeldt, B. and Sigvard Palmqvist, S., 2008, Changes in

attitudes toward desire for implant treatment: A longitudinal study of a middle -aged and older Swedish population, Int J Prosthodont 21:481–485.

4. Shtansky, D.V. and Roy, M., 2013, Surface engineering for biotribological application, In: M. Roy ed., Surface Engineering for Enhanced Performance against Wear, Springer, New York, NY, pp. 277–310.

5. Black, J. and Hastings, G. ed., 1998, Handbook of Biomaterial Properties, Chapman & Hall, Thomson Science, UK.

6. Zivić, F., Babić, M., Grujović, N. and Mitrović, S., 2010, Tribometry of materials for bio-engineering applications, Tribol Industry 32:25–32.

7. Helsen, J.A. and Missirlis, Y., 2010, Biomaterials, Biological and Medical Physics, Biomedical Engineering, Springer-Verlag, Berlin/Heidelberg, Germany.

6 • Surface Engineering and Technology for Biomedical Implants

8. Roos, J., Sennerby, L. and Albrektsson, T., 1997, An update on the clinical documentation on currently used bone anchored endosseous oral implants, Dent Update 24:194–200.

9. De Freest, C.F. and Savett, D.A., 1996, Longevity of osseointegrated dental implants, In L. L.Hence and J. Wilson ed., Clinical Performance of Skeletal Prostheses, Springer, New York, NY, pp. 237–254.

10. Schliephake, H. and D. Scharnweber, D., 2008, Chemical and biological functionaliza-tion of titanium for dental implants, J Mater Chem 18:2404–2414. doi: http://dx.doi.org/10.1039/B715355B.

11. Stanford, C.M. and Brand, R.A., 1999, Toward an understanding of implant occlusion and strain adaptive bone modeling and remodeling, J Prosthet Dent 81:553–561.

12. Salvi, G.E. and Lang, N.P., 2001, Changing paradigms in implant dentistry, Crit Rev Oral Biol Med 12:262–272.

13. Berglundh, T., Persson, L. and Klinge, B., 2002, A systematic review of the incidence of biological and technical complications in implant dentistry reported in prospective lon-gitudinal studies of at least 5 years, J Clin Periodontol 29:197–212. doi: http://dx.doi.org/10.1034/j.1600-051X.29.s3.12.x.

14. Renvert, S., Roos-Jansaker, A-M., Lindahl, C., Renvert, H. and Persson, G.R., 2007, Infec-tion at titanium implants with or without a clinical diagnosis of inflammation, Clin Oral Implant Res 18:509–516. doi: http://dx.doi.org/10.1111/j.1600-0501.2007.01378.x.

15. Roos-Jansaker, A-M., Renvert, H., Lindahl, C. and Renvert, S., 2006, Nine- to fourteen-year follow-up of implant treatment. Part III: Factors associated with peri-implant lesions, J Clin Periodontol 33:296–301.

16. Stanford, C.M., 2010, Surface modification of biomedical and dental implants and the processes of inflammation, wound healing and bone formation, Int J Mol Sci 11:354–369.

17. Davies, J.E., 2003, Understanding peri-implant endosseous healing, J Dent Educ 67:932-949. doi: http://dx.doi.org/10.3390/ijms11010354.

18. Fritz, M.E., 1999, Two-stage implant systems, Adv Dent Res 13:162–169. doi: http://dx.doi.org/10.1177/08959374990130010601

19. Parithimarkalaignan, S. and Padmanabhan, T.V., 2013, Osseointegration: An update, J Ind Prosthodon Soc 13:2–6. doi: http://dx.doi.org/ 10.1007/s13191-013-0252-z.

20. Abjanich, J.H. and Orenstein, I.H., 2002, Prosthodontic considerations in dental implant restoration, In: A.M. Greenberg and J. Prein ed., Craniomaxillofacial Reconstructive and Corrective Bone Surgery: Principles of Internal Fixation Using the AO/ASIF Technique, Springer, New York, NY, pp. 232–261.

21. Oshida, Y., 2007, Bioscience and Bioengineering of Titanium Materials, Elsevier, London, UK, pp. 180–182.

22. Tucker, R.C., 2002, Surface engineering, JOM 160:1–3.23. Oshida, Y., 2007, Bioscience and Bioengineering of Titanium Materials, Elsevier, London,

UK, pp. 317–319.24. Rieu, J., 1993, Ceramic formation on metallic surfaces (ceramization) for medical applica-

tions, Clin Mater 12:227–235.