A full-size preformed lingual straight archwire was used to align the 7G and STb brackets at the origin position; these brackets were then bonded to the lingual tooth surface by curing Transbond XT (3M Unitek, Monrovia, CA, USA).7 (link)10 (link)24 (link) Then, 0.016-inch copper nickel-titanium (Cu-NiTi) preformed straight lingual archwires (STb straight wire small, 204–2101; Ormco) were inserted for the experiment. After Incognito brackets were bonded using their own incisal or occlusal rest and Transbond XT, a customized bent 0.016-inch superelastic NiTi archwire (SE-NiTi; 3M Unitek, Monrovia, CA, USA) was inserted for the experiment (Table 1 and Figure 2).5 (link)