“…15 , 20 - 23 A smile that fills the lip area as much as possible, which has a narrow buccal corridor, is considered more aesthetic. 3 , 8 - 11 , 13 , 14 , 20 , 24 - 26 A general correlation between the arch width and the buccal corridor has already been described, which means a decrease of the arch width can result in an increased size of the buccal corridor. 27 , 28 However, the decrease of arch width in extraction cases can be avoided through the posterior expansion caused by the passive self-ligating brackets, such as Damon system (Damon Q, Ormco, Orange, CA, USA).…”