Conclusions
incisors

During CoS leveling, BF was reduced after 20 min and then started to increase at 48 h. It returned to its baseline values 1 week after AW insertion in all AW size groups and type of force subgroups.Similar BF changes were recorded in all teeth using different AWs sizes and materials.In groups 1 and 3, more BF reduction were found in the extruded premolars compared to that of the intruded incisors during the first 20 min of AW placement.After 1 week of reverse CoS AW placement, BF continued to increase in the extruded premolars in groups 2 and 3 and in the intruded incisors in group 3.In the premolars “extrusion subgroup,” BF showed more increase toward baseline values within the first 48 h of force application in the SS AW groups (groups 1 and 2).Tooth type and the amount of COS depth change were associated with BF changes within the first 20 min of force application.