Investigation on the Bioactivity of Titanium_Nano_Hydroxyapatite _Ti_nHA_ Composites Produced by Powder Metallurgy Route for Improved Healing of Fractured Bones

Abstract

Titanium (Ti) based materials are the most promising metallic implants compared with other metallic systems owing to their superior bio-compatibility, higher corrosion resistance, and sustainability for longer periods. However, Ti exhibits bio inert nature which is a limitation, particularly for joint replacement and dental implant applications. Hydroxyapatite (HA) is a calcium-based ceramic material that exhibits a similar chemical structure to that of the calcium phosphorous phase which is present in the natural human bone. Using HA as a surface coating on Ti by different surface engineering methods is a well-known strategy in materials engineering to enhance the performance of Ti implants. The interactions at the implant-tissue interface are dependent on the tissue response to the implant material. Hence, developing bioactive implants is an advantage that accelerates the healing rate and helps to recover from the fractured bone of deceased bone quickly. newlineDeveloping surface coatings on Ti implants by using bioactive phases such as HA can help to increase the bioactivity of the implant. However, the coating quality and the bonding strength between the coating and the substrate dictate the success of the implant coating. Particularly, for dental implants, in which the implant is subjected to hot and cold environments simultaneously, the coefficient of thermal expansion of the coated material and implant material affects the bonding quality of the coating and the substrate. Due to the poor coefficient of thermal expansion of the coating compared with the Ti metal, the bonding strength at the implant-tissue interface is affected. Hence, instead of providing surface coating, if bioactive phases are incorporated into Ti, as long as the implant is placed in the biological environment, the role of incorporated bioactive ceramic phases helps to support the implant for improved function. newline