Bioceramics

As recently as 20 years ago, ceramics were widely ignored as potential biomaterials. Interest in bioceramics has increased dramatically over the past decade to the point where it is anticipated they will be the materials of choice for many orthopedic, otologic, maxillofacial and dental applications during the decade of the '90s. Alumina ceramics are being used extensively as articulating comJ1onents in total joint prostheses because of Ithe materials low coefficient of friction and excellent wear resistances. Alumina ceramics are also being used in dental and maxillofacial applica­ tions because of the materials excellent biocompatibility. Because of its ability to chemically bond to bone, hydroxyapatite is rapidly becoming the material of choice for many dental and maxillofacial applications. For the past decade, one of the most widely researched topics in the field of orthopedics has been the clinical evaluation of joint prostheses based upon stabili­ zation via tissue ingrowth. It appears that the next generation of joint prostheses will be based upon direct chemically bonding to bone using hydroxyapatite, surface-active glass or surface-active glass ceramics coatings. Resorbable bioceramics are limited to temporary bone space fillers, periodontal pockets treatment and resorbable pharma­ ceutical delivery systems. Bioceramics is a comprehensive reference textbook covering the history of bio­ ceramics, present status of bioceramics, and prediction for future use of bioceramics. This book will serve as a major reference for students, as well as experienced bio­ material researchers. The book presents the state-of-the-art of bioceramics as of 1991.

1 A historical and philosophical outline and prospects for the application of biomaterials.- 1.1 Historical survey.- 1.2 Social and philosophical reasons for the interest in this sector.- 1.3 Problems in replacing parts of the human body.- 1.4 Prospects for skeletal substitution.- 1.5 Attempts at bone reconstruction by using bioactive ceramics.- 1.6 Application of bioceramics to plastic surgery.- 2 Physical properties and physiology of bone.- 2.1 The nature of bone.- 2.2 Physiology of bone.- 2.3 Ordinary bone remodelling and bone restoring mechanisms.- 2.4 Bone transplantation.- 2.5 Specific physical properties of bone.- 2.6 Mechanical resistance of bone.- 2.7 Viscoelastic behaviour of bone.- 2.8 Piezoelectricity of bone.- 2.9 Materials and piezoelectric stimulation.- 2.10 Supposed thermoluminescent activity of bone.- 2.11 Characteristics of the composition of bone.- 3 Survey of the physics of the locomotion of the human body.- 3.1 General.- 3.2 A study of stress distribution on some important joints of the human body.- 4 General problems connected with the use of biomaterials.- 4.1 Fixing methods.- 4.2 Comments on the experience acquired of the response of ceramics currently used in orthopaedics.- 4.3 The problem of wear: mechanisms and recent developments.- 5 Compatibility between bioceramics and the physiological environment.- 5.1 Introduction.- 5.2 Hostility of the biological environment.- 5.3 Ceramic/tissue interface.- 5.4 Tissue responses.- 5.5 Problems in determining the compatibility of biomaterials.- 5.6 Encapsulation of implants.- 5.7 Some physical factors influencing the acceptance of synthetic materials as tissue implants.- 5.8 Some evaluations of the biological fitness of bioactive ceramic materials.- 5.9 The role of debris.- 5.10 Thrombogenic dangers of materials in contact with blood.- 5.11 Treatment of the surface of ceramics by coating of prostheses.- 5.12 Proposal for an indirect investigation based on the thermal properties of bone.- 6 Materials for surgical use.- 6.1 Introduction.- 6.2 General discussion of various biomaterials.- 6.3 Ceramics.- 7 Glasses and ceramics as coatings for massive supports.- 7.1 The metallic support.- 7.2 Techniques for application of ceramic or glassy coating to metals.- 7.3 Metal/glass interface.- 7.4 Plasma spraying.- 7.5 Other crystalline coating materials as substitutes for Al2O3.- 7.6 Technique of measurement of the mechanic stresses on coatings.- 8 Shape and mechanical resistance.- 8.1 Survey of physico-mechanical behaviour.- 8.2 Main manufacturing methods.- 8.3 Mechanical design in ceramics.- 8.4 The shaping project.- 9 Range of application of ceramic prostheses for surgical implants.- 9.1 Knee joint replacement.- 9.2 Substitution in the hip region.- 9.3 Bulk alumina.- 9.4 Cardovascular materials and implants.- 10 Current mechanical-testing devices as simulators of properties under dynamic movement.- 10.1 General principles.- 10.2 Analysis of the forces and movements involved at the human hip and at the knee joint.- 10.3 Types of equipment for tribological investigation.- 10.4 Joint simulator.- 10.5 Assessment of roughness.- 10.6 Assessment of breaking load.- 10.7 Hardness tests.- 10.8 Fatigue tests by cycling-load simulator devices.- 10.9 Radiotelemetric devices for the evaluation of the clinical course of implants and sutures.- 11 Maxillofacial implants.- 11.1 Dental implants.- 11.2 Ear prostheses.- 11.3 Fillers.- 12 Fixing of the prosthesis to the skeletal part.- 12.1 Mechanical locking.- 12.2 Biological interlocking.- 12.3 Implant/bone-tissue interface.- 13 Approach to biocompatibility tests.- 13.1 Compatibility tests in general.- 13.2 Evaluation of specific biological compatibilities.- 13.3 Attempts at eliminating bacterial infection.- 14 International standardization of measurement procedures.- 14.1 Generalities.- 14.2 Classification criteria for the organization of standardized tests.- 14.3 Critical discussion of biocompatibility tests.- 14.4 Methods of evaluation of the bone/prosthesis interface.- 14.5 Introduction to the tests for the mechanical characterization of biomaterials.- 14.6 Standardization of the dimensions of sample prostheses.- 14.7 An example of standardized evaluation of the performance of a material: the case of Al2O3.- 14.8 Microstructure.- 14.9 Behaviour of a material under wear.- 14.10 Tests to evaluate the corrosion of a product under fatigue.- 14.11 Mechanical strength.- 14.12 Compressive strength.- 14.13 Bending tests.- 14.14 Measurement of elastic and anelastic deformation.- 14.15 Electro-acoustic instruments used to measure elastic modulus and internal friction.- 14.16 Measurement of internal friction.- 14.17 Resistance to chemical corrosion.- 14.18 Microhardness.- 14.19 Aspects of the qualitative testing of some ceramic manufactures of biomedical use.- 14.20 Problems relative to the thermal expansion coefficient.- 14.21 Thermal expansion of glasses.- 14.22 Progress report on the regulation governing the bioceramics for prosthetic uses.- 14.23 A few words on the regulation governing the biological acceptability of materials manufactured into products.- Appendix A.- Appendix B.- Appendix C.