POLARIZED YTTRIA-STABILIZED ZIRCONIA IMPROVES DURABILITY FOR DEGRADATION AND APATITE FORMATION IN SIMULATED BODY FLUID

Abstract

Yttria-stabilized zirconia is currently used as an orthopedic and dental material, because of its excellent mechanical properties. In this study, we have improved the bioactivity of yttria-stabilized zirconia by a combination of electrical polarization and chemical treatment. The phase transformation from tetragonal to monoclinic ZrO 2 after alkaline treatment was inhibited on positively charged yttria-stabilized zirconia surfaces compared with negatively charged and conventional surfaces. During polarization, some oxide ions move from the positively charged surface to the negatively charged surface, leading to an increase in oxygen vacancies on the positive surface and hence greater formation of Zr-OH when this surface was exposed to alkaline solution. The bioactivity was assessed by immersing the samples in simulated body fluid and evaluating the growth of apatite on the surfaces. The combination of polarization and alkaline treatment increased the bioactivity in vitro.