RESUMEN
This study tried to evaluate the effectiveness of laceback [LB] in the first phase of orthodontic treatment. LB is supposed to prevent anterior tipping of the canines. Designing a randomized control trial. Two groups with LB [group 1] and without laceback [group 2] were used. The first group consisted of 10 girls and 4 boys with the mean age of 14 years 1 month and the second group consisted of 8 girls and 4 boys with the mean age of 15 years 1 month. The impressions were made using prefabricated orthodontic trays. The 0.016 NiTi archwire was the only wire used in the 22-slot brackets. The pre- and post - treatment cephalograms were provided in natural head position. The dental changes in 3 dimensions of space and the vertical skeletal parameters were evaluated using the casts and the cephalograms of the patients. The results showed that the vertical movement of the upper incisors, The angle between upper incisors and SN plan, The forward movement of the molars and the increase in IMPA were greater in group 2 than in group 1. Also, the posterior movement of the canines and the mean change in distances between the contact points of the anterior segments were greater in group 1 than in group 2