Does incorporating zinc in titanium implant surfaces influence osseointegration? A systematic review

Statement of problem. Titanium implant surfaces have been modified to improve osseointegration; however, the evidence for incorporating zinc into titanium implants to improve new bone formation and osseointegration is not clear. Purpose. The purpose of this systematic review was to assess the efficacy of treating titanium surfaces with zinc on the osseointegration of implants. Material and methods. The focused question addressed was, "Does incorporating zinc in titanium implant surfaces influence osseointegration?" Indexed databases were searched up to January 2016 using the key words "Bone to implant contact"; "implant"; "zinc"; "osseointegration." Letters to the editor, case reports/case series, historic reviews, and commentaries were excluded. The pattern of the review was customized to summarize the pertinent data. Results. Ten experimental studies were included, all of which were performed in animals (5 in rabbits, 4 in rodents, and 1 in goats). The number of titanium implants placed ranged from 10 to 78. The results from all studies showed that incorporating zinc into titanium implants enhanced new bone formation and/or bone-to-implant contact around implants. One study reported that zinc enhanced the removal torque on implants. Conclusions. The current available evidence on adding zinc to titanium implants surfaces to enhance osseointegration remains unclear. Further investigation is necessary to assess its effectiveness and safety in humans and to establish a standard methodology and ideal compound for incorporating zinc ion into titanium implant surfaces in a clinical setting.