Effect of drug-loaded TiO2 nanotube arrays on osseointegration in an orthodontic miniscrew: an in-vivo pilot study

Abstract

Osseointegration was evaluated for the surface of miniscrews with TiO₂ nanotube arrays containing drugs in this in-vivo study. The diameter and length of the TiO₂ nanotube arrays were about 70 nm and 5 μm, respectively. Recombinant human bone morphogenetic protein-2 (rhBMP-2) or ibuprofen was loaded in the TiO₂ nanotube arrays with 12 miniscrews. The 12 drug-loaded miniscrews, 6 miniscrews with no drug-loaded TiO₂ nanotube arrays and 6 conventional miniscrews, were placed on the tibias of New Zealand white rabbits. Histological osseointegration was assessed 8 weeks after implantation by measuring the bone-to-implant contact (BIC) ratio. Ibuprofen-loaded miniscrews showed a significantly higher BIC of 71.6% over conventional miniscrews of 44.3% on average. The mean BIC ratios of rhBMP-2-loaded miniscrews and no drug-loaded miniscrews was 24.6% and 60.1%, respectively. Our results suggest that TiO₂ nanotube arrays on the surface of miniscrews could be used as carriers of drugs, and loading ibuprofen in TiO₂ nanotube arrays may improve osseointegration of miniscrews. However, the effect of rhBMP-2 loaded in TiO₂ nanotube arrays on osseointegration of miniscrews was questionable in this pilot study.

Keywords: Bone morphogenetic protein 2; Ibuprofen; Nanotubes; Orthodontic anchorage; Osseointegration.