The difficulty, particularly with rotated lower incisors, is that there is very little span between the brackets to allow full engagement of the wire into the slot (Figure 1). Partial ligation means that the clinician has to tediously and continuously retie until the tooth derotates sufficiently to allow full ligation. Severely rotated lower incisors, especially when the patient is being treated on a non-extraction basis, can delay the progression from the initial aligning archwire. There are several techniques that have been employed including:
Using a light nickel–titanium (NiTi) wire such as an 0.012” NiTi. This usually requires several visits of retying, and clinicians would usually need to place a second round, wider-diameter NiTi wire before being able to progress to a rectangular NiTi.
Module configurations. (1) Placing an elastomeric module in a figure-of-eight configuration; (2) asymmetrical O-ring ligation;1 or (3) using a short metal ligature. These methods rely on having sufficient span between the brackets to allow full ligation of the wire into the slot.
Using powerchain in a force couple. This can be an effective technique, but must be employed carefully to ensure that the incisor is not moved out of bone.
Coil spring ties or a rotation wedge. These are likely to be plaque retentive.
Space creation with push coil for the rotated tooth following by ‘piggy-back’ mechanics to align the rotated incisor.
Using self-ligating brackets. This method can help to establish full ligation of teeth that are moderately rotated and have sufficient space between the brackets for the archwire to be deflected into the slot.
Register now to continue reading
Thank you for visiting Orthodontic Update and reading some of our resources. To read more, please register today. You’ll enjoy the following great benefits:
