Alignment of buccally displaced canines following premolar extractions: archwire or natural alignment?

The alignment times of buccally displaced maxillary canines following first premolar extractions were studied in 2 groups. The control group (n = 28) comprised of cases where no appliances were used while the experimental group (n = 28) had Begg brackets bonded on the upper teeth in conjunction with Sentalloy archwire. The imbrication indices (I.I.) of all canines were recorded for both groups prior to extraction and every 5 days after extractions until the canines aligned. The results indicated that there was no significant difference in the alignment rate at 30 days and 60 days between the 2 groups. However, the alignment rates at 90 and 120 days were both significantly faster in the experimental compared to the control group (p less than 0.01). While the alignment rates at 30, 60, 90 and 120 days in the experimental group followed a plateaued curve, the alignment rates in the control group followed a cusped curve. The results indicated that a 2 months self-alignment period following premolar extractions would be justified in most cases before banding.