Positioning of Self-Ligating Brackets
Positioning of self-ligating brackets can be facilitated by using special tools such as positioning tweezers and jigs. These can be obtained in a number of designs, depending on the operator’s preference. Conventional twin brackets are usually placed using the vertical slot. Apart from the SmartClip, this is not possible with any other self-ligating bracket. The SmartClip bracket has a “classic” bracket design with the traditional twin tie-wings and can therefore be positioned in a similar way to a conventional bracket ( Fig. 6.6 ). Self-ligating brackets are delivered open or closed. With closed bracket slots, some inaccuracies in placing the brackets may occur in the hands of an inexperienced operator. Some training (with practice on study models using toffee as an adhesive) may be beneficial before the brackets are directly bonded in patients to avoid inadvertent positioning inaccuracies ( Figs. 6.7 and 6.8 ). The vertical positioning of self-ligating brackets is comparable to that of conventional ligation brackets, for both open and closed delivery brackets. However, when a failed self-ligating bracket is being replaced, it should be borne in mind that, if the replacement bracket is delivered closed, it may be difficult to place it in the correct vertical position. The surrounding brackets will be open at this point, as the archwire has been removed for the repair. Conversely, for brackets that are delivered closed, the horizontal pressure used to seat the bracket can lead to positioning inaccuracies due to slippage, which can be avoided if the bracket is opended before placement.
The closing mechanisms in self-ligating brackets block the vertical slot. Only the SmartClip (3M Unitek) bracket can be positioned in the same way as conventional brackets.