Canine retraction: a comparison of two preadjusted bracket systems.

Before the 1970s, Begg and Edgewise appliances were the most commonly used appliances in orthodontics. With the introduction of preadjusted appliances, many have made claims of superiority. These claims are often unsubstantiated, as few, if any, have ever been tested in a controlled, prospective in vivo study. The purpose of this study was to compare the time required to retract canine teeth by using two different preadjusted bracket systems (Tip-Edge, TP Orthodontics, LaPorte, Ind., versus A-Company straight wire, Johnson and Johnson, San Diego, Calif.) in a human sample. Anchorage loss as a result of this movement was also evaluated. A sample of 12 patients was randomly selected from the new patient pool at the postgraduate orthodontic clinic of Montefiore Medical Center. All patients required the removal of first premolars in one or both arches as a part of their orthodontic treatment. The rate of retraction and anchorage loss were evaluated. Paired t tests were performed separately for the rates of retraction and anchorage loss. The mean rates of retraction were 1.88 mm per 3-week period and 1.63 mm per 3-week period for the Tip-Edge and A-Company brackets, respectively. There was no statistically significant difference in the rates (p > 0.05). The mean anchorage loss was 1.71 mm for the Tip-Edge bracket, and 2.33 mm for the straight wire bracket. The difference in the amount of anchorage loss was inconclusive as the sample size was too small (power was 10%).