Abstract
Aims: Evaluate the amount of anchorage loss of the lower posterior teeth 2nd premolar and first molar when used as anchorage teeth for retraction of canine bilaterally by using lace back technique after extraction of first premolar in sever crowding cases. Materials and Methods: Two groups of brackets, one of them labial (conventional) were bonded on the labial aspect of metal teeth except 4 4 typodont by special adhesive and other groups lingual brackets also bonded in the same teeth lingual surface and two types of light or low gauge arch wire Niti , twisted multi strand for sliding the canines retraction by using elastomeric ring with ligature wire active lace back once with labial and other with lingual technique. Results: There is no significant difference between twisted multi strand wire when ligated on the teeth in both lingual technique and labial technique. Significant difference when used Niti wire on lingual technique when compared with the same type of wire when ligated on labial technique and significant difference with twisted multi strand when ligated on teeth in lingual technique. Conclusion: Anchorage loss decreases with twisted multi strand wire because the friction increased between arch wire and base of bracket in both labial and lingual technique and decreased with Niti wire specially when used in lingual techniques
