Preface

Abstract: It is well known that the introduction of zirconia into the alumina matrix has a positive effect on bending strength of the material, and especially on toughness which is the main limit of alumina ceramics. While the many attempts made in the past to develop alumina matrix composites suitable for biomedical applications containing zirconia as a toughening phase (Zirconia Toughened Alumina – ZTA) did not leave the developmental stage, recently ball heads and inlays for THR bearings made out a three phase alumina matrix composite were introduced into the market. In the alumina matrix of this material both zirconia and exagonal aluminate platelets are distributed, and then it belongs to the class of Zirconia and Platelets Toughened Alumina – ZPTA. Besides ball heads and inlays, also several other innovative orthopedic devices made out this new ceramic biomaterial are in different development stage. This paper reviews the present status of alumina matrix composites in orthopedic application, with special attention to ZPTA.

Abstract: Calcium phosphate bioceramics and bovine bone xenograft with or without sintering are more or less used in orthopaedics or in maxillofacial surgery. In this study we compare in a rat femoral epiphysis model after 3 weeks of implantation the bone in growth at the expense of granules of same size of micro macro porous biphasic calcium phosphate MBCP, sintered bovine bone and unsintered BioOss.

Abstract: The development of calcium phosphate ceramics and other related biomaterials for bone graft involved a better control of the process of biomaterials resorption and bone substitution. The biphasic calcium phosphate ceramics (BCP) concept is determined by an optimum balance of the more stable phase of HA and more soluble TCP. The material is soluble and gradually dissolves in the body, seeding new bone formation as it releases calcium and phosphate ions into the biological medium The main attractive feature of BCP ceramic is their ability to form a direct bond with the host bone resulting in a strong interface. The formation of this dynamic interface is the result of a sequence of events involving interaction with cells; formation of carbonate hydroxyapatite CHA (similar to bone mineral) by dissolution/precipitation processes. At the present time, BCP is commercially available in blocks, particulates, customized design. The need of material for Minimal Invasive Surgery (MIS) induced the development of a concept of granules combination with polymer or calcium phosphate cement for injectable/mouldable bone substitutes. Four types of injectable/mouldable bone substitutes have been developed by INSERM Nantes University.