Canine retraction with the edgewise appliance-some problems and solutions.

The three basic methods of canine retraction discussed all have their inherent advantages and disadvantages and all can cause problems. The retraction systems which slide canines along a relatively rigid archwire, would appear to have the advantage of achieving better controlled apical and crown movement but at the obvious cost of greater friction and binding than the sectional arch. Of course the direct headgear system to some extent avoids the consequences to the anchorage, but there again the force to the canine is only intermittent and movement consequently is slower than if elastic traction were applied. If sliding mechanics are used either with a J hook headgear to canines or elastic intra-traction from the molars, it would seem advisable to use a heavy round wire in at least a medium width bracket. To help decrease binding when using elastic traction, power arms would certainly seem to have a place, with the added benefit of patients having an accessible hook to change elastics themselves. If sectional arches are used it is advisable to use a heavy rectangular wire to maintain as much control as possible. Due to the compromise between horizontal flexibility and vertical rigidity already discussed, it is very easy to over-activate a sectional arch with its inevitable consequence of excessively tipping the canine and/or losing molar anchorage.