Photofunctionalised Ti6Al4V implants enhance early phase osseointegration

Objectives Ultraviolet (UV) lightmediated photofunctionalisation is known to improve osseointegration of pure titanium (Ti). However, histological examination of titanium alloy (Ti6Al4V), which is frequently applied in orthopaedic and dental surgery, has not yet been performed. This study examined the osseointegration of photofunctionalised Ti6Al4V implants. Methods Ti and Ti6Al4V implants were treated with UV light, and the chemical composition and contact angle on the surfaces were evaluated to confirm photofunctionalisation. The implants were inserted into femurs in rats, and the rats were killed two or four weeks after the surgery. For histomorphometric analysis, both the bone implant contact (BIC) ratio and the bone volume (BV) ratio were calculated from histological analysis and microcomputed tomography data. Results The amount of carbon and the contact angle on both implants were significantly reduced after UV irradiation. The BIC ratios for both UV light treated implants significantly increased at two weeks, but there was no significant difference at four weeks. There was no significant difference in the BV ratios between the UV light treated and control implants at two or four weeks. Conclusions This study suggests that photofunctionalisation of Ti6Al4V implants, similar to that of Ti implants, may promotes osseointegration in early but not in the late phase of osseointegration.