Higa RH, et al. – The present study sought to compare the deflection force in conventional and thermally activated nickel–titanium (NiTi) wires in passive (Damon Q) and active (Bioquick) self–ligating brackets (SLB) and in conventional brackets (CB) tied by 2 different methods: elastomeric ligature (EL) and metal ligature (ML). The authors found that the SLB and the ML show standard force patterns during unloading. On the other hand, the elastomeric ligatures exhibit a randomly distributed force release behavior.