Purpose: This study was carried out to assess the effect of different types of ligatures on the rate of canine retraction. Materials and Methods: 14 participants requiring extraction of upper first premolars, were randomly assigned into 2 groups; group 1 had passive self-ligating bracket on the upper right canine, figure of 8 module ligature on the upper left canine and group 2 also had self-ligating bracket on the upper right canine, and slide-low friction elastic module on the left side. Canines retraction were done under 150 gm of force using a 9 mm nickel-titanium closed-coil spring .Alginate impression was taken at the onset of canine retraction(T0), and every month (T1-T4). Study casts were fabricated and then scanned with a 3D scanner. Results: The statistical analysis showed no statistically significant difference in the rate of canine retraction between the 2 groups, and between the control and intervention sides within each group. Conclusion: The difference in rate of upper canine retraction between self-ligation brackets, figure of 8 elastic module and slide -low friction ligature was not statistically significant.

Purpose: This study was made to evaluate the level of receptor activator of nuclear factor-kappa B ligand (RANKL) in gingival crevicular fluid (GCF) and pain perception during orthodontic tooth treatment to evaluate the efficacy of low-level laser therapy (LLLT). Subjects and methods: A number of 10patients (age range: 15-20) requiring extraction of maxillary first premolars as a part of orthodontic therapy were selected randomly. A split-mouth technique was used. The test side received (LLLT) from a semiconductor (aluminium galliumarsenide) diode laser. The laser was irradiated on days 0, 2, 7, and14. The canine distalization was achieved with a force of 150 g per side using nickel titanium closed coil spring. GCF samples were collected from canines on days 0,7,14 and 30 using perio paper point #35. Enzyme-linked immunosorbent assay (ELISA) was used to assess levels of RANKL. Pain was assessed for one week from the intervention using a visual analogue scale(VAS).Gingival index and pocket depth were assessed at baseline and after 30 days. Results: There was no significant difference between RANKL concentrations in the two groups at base line, 7 and 14days. After 30 day; Laser side showed statistically significant lower mean RANKL (p=0.011) than control side. For pain: non significant difference was found between the two groups during the tested periods. Conclusion: LLLT showed no additional benefits over conventional canine retraction regarding pain and RANKL release. However, the laser group showed the least RANKL level at the end of the study which denotes biostimulatory effect of laser on bone cells.