Orthodontic procedures
Orthodontic treatment using traditional metal brackets (Master Series®, American Orthodontics, Sheboygan, Wisconsin, USA), with a 0.022-inch slot high and MBT prescription were used. Then the brackets were bonded after 7 days of the first upper premolars extraction. In both groups, the archwire sequence was as follows: 0.012-inch Nitinol (NiTi), 0.014-inch NiTi, 0.016-inch NiTi, 0.016 × 0.022-inch NiTi, 0.017 × 0.025-inch NiTi, and finally 0.019 × 0.025-inch stainless steel (SS) (American Orthodontics, Sheboygan, Wisconsin, USA) [