High bone-implant contact achieved by photofunctionalization to reduce periimplant stress: A three-dimensional finite element analysis

OBJECTIVE: A recent study demonstrated that UV treatment of titanium implants (photofunctionalization) enabled a higher level of osseointegration by establishing a 98.2% bone-implant contact (BIC) as opposed to a 53.0% BIC around untreated implants. This study examined whether, and how, the BIC increase affects the periimplant mechanical stress. MATERIALS AND METHODS: Three-dimensional finite element analysis was performed on implants of different degrees of BIC (53.0% and 98.2%) based on the report of photofunctionalization. The different lengths of implants (7, 10, and 13 mm) were also tested. RESULTS: Increasing the implant length from 7 to 13 mm diminished the periimplant stress level by only 15% under vertical load, whereas increasing BIC from 53.0% to 98.2% diminished it by 50%. Consequently, stress around 7-mm implants with 98.2% BIC was even lower than that around 13-mm implants with 53.0% BIC. High-stress areas, which were observed around implants in all lengths with 53.0% BIC, disappeared on implants with 98.2% BIC even on 7-mm implants. Similar results were obtained under oblique load. CONCLUSIONS: This study demonstrated that a BIC increase from 53.0% to 98.2%, which can be achieved by photofunctionalization, improves distribution and diffusion of periimplant stress more effectively than using longer implants, providing a potential novel strategy to counteract stress-induced periimplant marginal bone loss.