الفهرس 
Title : Effect of archwire gauge on the rate of canine retraction in adults: A Randomized Clinical Trial
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Abstract
The current study was conducted to investigate the effect of wire gauge on rate and type of
tooth movement during sliding mechanics and its effect on root resorption of the teeth moved and
amount of anchorage loss.
Total of 36 canines of eighteen adult female patients with age range (16-26) years old who
had dento-alveolar maxillary protrusion necessitating extraction of the maxillary first premolars were
investigated in the study. Canines were retracted using Ni-Ti coil spring extending between canines’
brackets and second molars’ tubes which was used for anchorage while no additional anchorage
means were used. Canines were retracted with 1.5 N force over three archwire gauges (0.016Ⅹ0.022”,
0.017Ⅹ0.025” and 0.19Ⅹ0.025”) St.St wires in three-arm parallel group study. 3D digital models were
used in the assessment of monthly canine retraction rate, which was the primary outcome of the study
and amount of first molar anchorage loss that was secondary outcome. CBCT images were used in
the assessment of other secondary outcomes; amount of canine root resorption, change in canine
tipping, torque and rotation occurred after 6 months of retraction.
The results revealed that there was small difference in the mean rate of canine retraction
between the three groups as canine was retracted by 1.01, 0.67 and 0.7 mm/month in 0.016Ⅹ0.022”,
0.017Ⅹ0.025” and 0.19Ⅹ0.025” St.St groups, respectively with no statistical significant difference
between all groups (P-value=0.2). Canine tipping increased with the decrease in archwire gauge yet
that tipping was of no statistical or clinical significant difference (P-value=0.085, CI= 8.15-11.42).
Root resorption was significantly higher in 0.19Ⅹ0.025” St.St group 1.39±1.23 mm than the other
two groups (0.5±0.66 and 0.41±0.55) mm in 0.016Ⅹ0.022” and 0.017Ⅹ0.025” St.St groups (pvalue=0.024). Additionally, there was statistical significant difference between 0.016Ⅹ0.022” and
0.017Ⅹ0.025” St.St groups regarding amount of anchorage loss (P-value=0.028) with no statistical
significance between any other two groups. The mean value of anchorage loss was 1.71, 2.99 and
2.72 mm in 0.016Ⅹ0.022”, 0.017Ⅹ0.025” and 0.19Ⅹ0.025” St.St correspondingly. For the other
outcomes, there was no significant difference among the groups.
Within the limitation of the current study, archwire gauge has little effect on rate of canine
retraction, tipping, torque or rotation with no statistical or clinical significance. Smaller archwire
gauges have less adverse effect on anchor units and root resorption compared to larger archwires