Bone biocompatibility of titanium and zirconia implants: An in vitro study

Abstract

Oral implants have become an option for replacement of missing teeth. The success of oral implantation depends on the biocompatibility of the material with the surrounding bone, and on the effective osseointegration process which generate strong bond between the living bone and the implant. The aim of the present work was to evaluate bone biocompatibility of titanium and zirconia implants, with focus on cellular events involved in osseointegration process.Methods: Murine preosteoblasts (OB) cells cultured in the presence of the implants were employed as experimental system. Three types of dental implants were used, based on their material composition: grade 4 titanium (Ti), 85% titanium, 15% zirconium (Ti/Zr), and ceramic implants (ZrO2). Alkaline phosphatase activity, extracellular collagen deposition and matrix mineralization were measured as OB differentiation markers. OB adhesion to implants assays and scanning electron microscopy (SEM) analysis were carry out. Results: The number of OB adhered to ZrO2 implant was significantly higher with respect to Ti or Ti/Zr implants. SEM analysis evidenced that cell morphology was preserved among OB adhered to each device. The presence of ZrO2 implants did not modified OB differentiation markers evaluated respect to control group, meanwhile Ti or Ti/Zr induced one-two fold reduction in all bone markers studied. Conclusions: In summary, zirconia implants exhibited better bone biocompatibility than titanium one, since OB behavior wasn´t altered compared to control group. In contrast, the presence of titanium implants significantly reduced the ability of pre-OB to differentiate into bone forming cells.