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Attachments for bonding during surgical exposure of the impacted tooth

Published: July 2011

Bulletin #1 - July 2011

Attachments for bonding during surgical exposure of the impacted tooth

Question: At surgical exposure, should we place a bracket on an impacted maxillary canine of the same type and with the same prescription to complement the bracket system used on the erupted teeth?

At first glance, this seems the obvious thing to do, but with a little understanding of the many facets involved in the treatment, it will be quickly realized that this is a mistake. The reasons are many:-

1. A precision prescription bracket is only an asset when placed at the correct height on the mid-labial aspect of the canine. This is rarely possible to achieve at surgery, due to the proximity to an adjacent root or if excessive removal of bone and soft tissue needs to be undertaken to provide access.

2. The sophisticated bracket has no advantage over the simple eyelet and several drawbacks, if placed on any other surface.

3. The base of a bracket is rigid and shaped to suit the mid-labial position of a tooth. It is impossible to adapt its base to fit another surface and, with poor adaptation, accidental de-bonding is common.1

4. Precision prescription brackets have been designed to move a tooth accurately over small distances and through just a few degrees of rotation, uprighting and root torque. They are not well suited for use in grosser movements.

5. A markedly displaced tooth presents a problem when attempting to ligate the archwire into the bracket and efficient “partial” ligation is difficult to achieve, particularly when there is a degree of rotation.

6. Even with a surgical procedure that leaves the canine visible intra-orally (an open exposure procedure), there is a liberal collar of soft tissue surrounding the tooth which will be irritated by the bulky and sharp-profiled bracket, causing discomfort, swelling, pain and bleeding.

7. Once the tooth has erupted sufficiently, the bracket will anyway need to be relocated to its ideal position on the crown of the tooth.

8. The full potential of the slot prescription cannot be exploited until the tooth has erupted fully and the bracket engaged in the main archwire.

9. Until this time, the only directional forces that can be brought to bear on the tooth are those involved with extrusion (active eruptive forces), tipping and some rotational movement.

10. As the tooth approaches its place in the arch, particularly from a palatal displacement, the gingiva bunches up ahead of it and the bulky profile of a well placed bracket causes impingement of the tissues, with accompanying inflammation, swelling and discomfort and with difficulty in reactivation.

In these circumstances, the effect on the periodontal tissues can be very damaging.

Fig. 1_1

Fig. 1. Three hand-welded eyelets to show the pliable band material (soft stainless steel tape) with mesh base. A twisted 0.012” stainless steel wire rides freely in the eyelet and is stiff enough to withstand any form of traction mechanism. 

In direct contrast, the use of a simple eyelet attachment2 has numerous advantages:-

1. The base is smaller and its shape easily adapted to approximate to the shape of the bonding site, be it on the mesial or distal corner, the incisal tip or the undulating palatal surface. So bonding is far more reliable.1

2. It can be placed in more limited access areas because of its low profile.

3. Because of its size and shape, it is much kinder to the tissues, as it emerges through the attached gingival

4. Ligation is much simpler and partial ligation can be done securely and quickly without fear of it coming loose.

5. If the eyelet is placeable on the labial aspect and oriented parallel to the long axis of the tooth, a fine NiTi auxiliary archwire (preferably placed piggy-back over a heavier main arch) can be threaded through it and, in this way, can be used to achieve a very rapid extrusion and rotational correction of a severely displaced tooth - avoiding the need for ligation. This is far more economic on office time spent and on number of office visits than when using a regular bracket.

6. All needed alignment and rotation of the tooth can be efficiently dealt with using a well placed eyelet. Substituting it for the appropriate prescription bracket may be left till the time if and when only uprighting and root torque are needed.

Fig.2_2

Fig. 2. An impacted mandibular second molar has 2 eyelets bonded at the time of its surgical exposure. Why two? If you have enough tooth surface, place two – it is a form of insurance!

The orthodontic supply companies make eyelets on steel bases with a mesh bonding surface but, for the most part, the bases are still fairly rigid. It is advantageous to have your assistant or your lab technician weld a strip of soft steel eyelets to a length of steel band material backed by a strip of steel mesh. This has proved to be a cheap, readily-available, easily-pliable and convenient attachment for the purpose.

Threading a dead soft 0.010” or 0.012” stainless steel ligature wire and twisting it into a tight braid, should be prepared before the bonding procedure at the time of surgery. In this way, the ligature is secure, it rides freely in the eyelet and it can be drawn subsequently in any direction through the sutured edges of the flap or the dressed open exposure. It is cut and bent over to form a hook or loop, for applying traction from a spring, and auxiliary NiTi archwire or an elastic tie or chain.


References:

  1. Becker A, Shpack N, Shteyer A. Attachment bonding to impacted teeth at the time of surgical exposure. Eur. J. Orthod. 18:457-463, 1996.
  2. Becker, A.:The orthodontic treatment of impacted teeth. 2nd edition. Abingdon: Informa Healthcare Publishers. 2007. Chapter 4 Treatment Strategy. Pages 53-60. ISBN-13: 978 1 84184 475 6.