Correction of canine position Favourable indications for correction of impacted canines

Canines are moved most easily into their correct position if the root apex is in a favourable position. If the tooth lies horizontally it is extremely difficult to correct this and generally the closer the tooth to the midline the more difficult the correction will be. Treatment is nearly always lengthy and can damage adjacent teeth. Figure 13 shows a lateral incisor adjacent to a palatally impacted canine where the opposite reaction to

Fig. 13 A lateral incisor adjacent to a palatally impacted canine. When the canine is pulled labially the reaction will be for the lateral root to move labially. It is essential therefore to use thick rectangular wires during the movement of palatally positioned canines. Further labial movement of the lateral root would be potentially damaging to the periodontal attachment

Fig. 13 A lateral incisor adjacent to a palatally impacted canine. When the canine is pulled labially the reaction will be for the lateral root to move labially. It is essential therefore to use thick rectangular wires during the movement of palatally positioned canines. Further labial movement of the lateral root would be potentially damaging to the periodontal attachment

Canine Moved With Orthodontics
Fig. 14 Palatally positioned canine being moved with power chain into the correct position
Piggyback Orthodontic Wire
Fig. 15 A 'piggy back' flexible wire has been deflected in order to apply traction to the gold chain which has been attached to a palatally positioned canine. There is a stiff base wire which prevents unwanted reactions to this traction

pulling the palatal canine out is the labial positioning of the lateral incisor root. Obviously this is not favourable and the gingival recession will worsen. The force to move the canines can be obtained from elastomeric chain or thread. Figure 14 shows elastomeric chain being used to pull the canine labially. An attachment has been bonded to the tooth, but as the tooth moves to its correct position it will be necessary to rebond it. Moving the tooth over the bite sometimes requires the occlusion to be disengaged with a bite plane or glass ionomer cement build ups on posterior teeth, for a few weeks.

An alternative is to use a smaller diameter nickel titanium 'piggy back' wire with a stiff base wire to align the tooth (Fig. 15). The thicker base wire maintains the archform by resisting local distortion caused by the traction on the canine. The nickel titanium piggy back wire produces flexibility and a constant low force, unlike elastomeric chain or thread which have a high initial force and then a rapid decay of this force. It is better not to tie the piggy back in fully as the wire needs to be able to slide distally as the canine moves labially. If tied in fully the friction does not allow this function. It also helps if the

Piggyback Orthodontic Wire

piggy back wires run through auxiliary tubes on the first molar bands. One further method which has gained some popularity is the use of a sectional archwire made of beta-titanium alloy. This wire is formable and flexible, it can be deflected as a sectional arm and pulls the canine labially. It is important to use a palatal arch which cross braces the molars to prevent them moving into crossbite as an opposite force reaction to the buccal movement of the canines (Fig. 16).

The use of heat activated nickel titanium alloys has also done much to improve the efficiency of moving impacted canines into the correct position. Figures 17 and 18 show a sequence of tooth movements where a nickel titanium alloy has been deflected, after cooling with a refrigerant, into the bracket. The length of time between the two slides was 8 weeks and

it can be seen how much tooth movement has occurred. The transpalatal arch is also useful anchorage for vertical and antero-posterior tooth movements.

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  • PHILLIPP
    How to align palatally impacted canine?
    8 years ago

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