Effect of TiO2 nanotubes arrays on osseointegration of orthodontic miniscrew

To increase the stability of orthodontic miniscrews, TiO 2 nanotube arrays were fabricated on the surface of Ti miniscrews and the effect of those arrays on the osseointegration of miniscrews was evaluated. Highly ordered TiO 2 nanotube arrays were grown on the surface of orthodontic miniscrews. Ethylene glycol based electrolyte was used in the anodic oxidation process. Two-step anodic oxidation was conducted to obtain clean and open windows in TiO 2 nanotube arrays. The diameter and length of the TiO 2 nanotube arrays were ~ 70 nm and ~ 5 μm, respectively. The miniscrews with TiO 2 nanotube arrays were implanted in the legs of New Zealand white rabbits for 8 weeks. Histological osseointegration was assessed by bone-to-implant contact ratio, and three-dimensional bone volume ratio was measured by micro-computed tomography analysis. The miniscrews with TiO 2 nanotube arrays had a greater mean bone-to-implant contact ratio of 52.8 % than the control, 29.3 %. Mean bone volume ratio (BV/TV) was also higher in the miniscrews with TiO 2 nanotube arrays, at 81.2 % than those in the control via micro-CT analysis. Our findings support that TiO 2 nanotube arrays on the surface of miniscrews enhance osseointegration and improve the stability of the miniscrew.