Noam Eliaz

Abstract:

In recent years, interest has evolved in electrochemically deposited hydroxyapatite (HAp) and other calcium phosphates as an alternative to the traditional plasma-sprayed (PS) process for coating of orthopedic and dental implants. Thus, we have deposited such coatings on commercially pure Ti and Ti-6Al-4V samples by cathodic polarization. The reaction kinetics was found to be controlled by charge transfer at the interface. As in the human body, HAp formed via transformation of a precursor phase (octacalcium phosphate). The effects of bath pH and temperature were studied experimentally, while a speciation-precipitation model was applied for understanding the effects of bath conditions. Corrosion tests confirm that the porous coatings did not introduce any localized corrosion issues. The effects of mechanical and chemical surface pre-treatments and a surface electron post-treatment on the adhesion strength, surface morphology, wettability and interactions with bone-forming cells and bacteria were also studied. Animal studies were used to quantify osseo-integration and evaluate the level of cracking compared to commercial PS coatings. The importance of coating solubility in vivo will be discussed. The coatings developed in the lab are currently being commercialized.