A review of the surface modifications of titanium alloys for biomedical applications

Dental implants are mechanical components that are used to restore the mastication (chewing) function and/or aesthetic appeal because of tooth loss or degradation. They are affixed (screwed) into the upper or lower jaw and act as a base for single or bridge-type tooth replacements. They are mostly manufactured from titanium alloys. The surface integrity of the manufactured implant may have a significant effect on the functioning and success of the implant. A systematic review is described on the effect of engineered surface integrity on the performance of titanium dental implants as regards the implant fixation, mechanical performance, bone growth and cell response. The need for surface engineering of the implant is introduced first. This includes the mechanical, surface-integrity and biocompatibility-required properties. This is followed by introducing and discussing the dedicated surface-modification processes currently employed. These include: abrasive blasting, electrochemical processes, hybrid processes and laser modification. The mechanical and biocompatible properties of an implant are the most crucial factor for their application in biomedical use. Hence, the present review article focused on the latest improvements to dental implant design based on the mechanical and biocompatible properties. The physical contact of an implant with respect to its surface roughness is an important factor in dental implant design. The surface roughness of an implant on the macro, micro and nano scales have specific effects on the implant's contact with the surrounding tissue of the bone. In addition, the biocompitability of titanium material is very important to develop a sustainable dental implant. Looking into the importance of the above mechanical and biocompatible properties of bone implants, the authors review elaborately the development of titanium-based implants with reference to the above properties.