@article{shintcovsk_knop_gandini jr_martins_pires_2015,  title={Comparison surface characteristics and chemical composition of conventional metallic and Nickel-Free brackets},  volume={29},  ISSN={1806-8324},  url={https://doi.org/10.1590/1807-3107BOR-2015.vol29.0022},  DOI={10.1590/1807-3107BOR-2015.vol29.0022},  number={1},  journal={Brazilian Oral Research},  publisher={Sociedade Brasileira de Pesquisa Odontológica - SBPqO},  author={SHINTCOVSK, Ricardo Lima and KNOP, Luegya Amorim Henriques and GANDINI Jr, Luiz Gonzaga and MARTINS, Lidia Parsekian and PIRES, Aline Segatto},  year={2015},  pages={1–8} }