Titanium (Ti) is most commonly used as orthopedic implant materials or bone substi­tute materials. Ti possesses the good biocompatibility and the sufficient mechanical properties for medical applications (Table 2.6) 48. One negative property of Ti is a low abrasion resistance and minute Ti abrasion powders may cause inflammatory reac­tions 49. Scaling treatment is only method for removal of plaque and dental calculus adheres, and it is a necessary treatment process to obtain good prognosis throughout the long-term maintenance of implant 50. Therefore, for abutment division of implant, it is important to possess high abrasion resistance to keep the smoothness of the im­plant surface after scaling treatment 51. Biomaterials must be nontoxic, noncarcinogen­ic, chemically inert, stable and mechanically strong enough to withstand the repeated forces of a lifetime. From this point of view, TiC is a very stable phase in comparison to pure Ti or Ti alloys. Titanium carbide (TiC) is an useful material for biomedical instruments because it possesses a range of desirable properties. The combination of very high hardness, high melting temperature, and excellent thermal and chemical stabilities makes TiC suited to a number of commercial applications. TiC is often used in abrasives, cutting tools, grinding wheels, and coated cutting tips 52.

Ti based implants are classified as bioinert. Bioinert refers to a material that retains its structure in the body after implantation and does not include any immunologic host reaction. Bioactive materials should be used for modification of the surface that occurs upon implantation. Bioactive refers to materials that direct chemical bonds with bone or even with soft tissue of a living organism. One of most used bioactive materials is a hydroxyapatite. The major inorganic constituent of bones and teeth is calcium phosphate, whose composition is similar to that of synthetic hydroxyapatite (HAp; Ca10(PO4)6OH)2. This similarity provides HAp based materials excellent bioactivities like bone bonding capability, osteoconductivity, and biocompatibility. The major dis­advantage of HAp is its poor adhesion, poor mechanical integrity, high brittleness, degradation in acidic/basic conditions and incomplete bone growth, which restricts its application only in non load-bearing areas of the human body. The creation of nanocomposites of ceramic materials with particle size few ten nanometers can sig­nificantly improve the bioactivity of the implant and enhance the osteoblast adhesion.