DANGER SIGNALS
Bracket Distortion
A very serious clinical problem in orthodontics is the distortion of brackets under the forces of mastication. This is seen more often on anterior bands and especially on lower anterior bands. The bracket is characteristically bent away from the tooth incisally and approaches or touches the band gingivally.
The bend may be such as to cause a malposition of the tooth to which the band is attached. This may be a labiolingual malposition (Fig. 1) or it can be an incisal elongation (Fig. 2). Frequently, there will be a permanent distortion in the archwire (Fig. 4).
A bracket bent in this fashion should never be straightened without removing and recementing or replacing the band. The reason is that the bending pulls the band material away from the tooth with it. Straightening weakens the cement some more. Most often this is dramatically demonstrated when food surges up from beneath the band when the bracket is straightened (Fig. 3). Frequently, the band will loosen upon straightening the bracket. Even if it does not, you can be sure that the cement has been lost and weakened to such an extent that replacement or recementing is the only recourse. Failing to do that is courting broad areas of decalcification (Fig. 4).
The bending of the brackets is caused by various things. One is the closeness of the bite which permits the opposite teeth to bite on the brackets. This is frequently habitual. Another is the chewing on things that are too hard for the brackets such as bones, nuts, popcorn, corn on the cob, hard candy, whole apples and carrots and other similar foods. A third is the presence of nail-biting and pencil-biting habits or opening bobby-pins with the teeth.
The best solution to this problem is to get the bite open sufficiently as quickly as possible so that the opposing teeth do not impinge on the brackets. Failing this, it is sometimes helpful to add an upper bite plate to open the bite. Bite opening combined with attention to the consistency of foods and the elimination of oral habits is about the best answer to this annoying problem.
Another helpful approach must be the investigation by the manufacturers of bands and attachments of flanging and attaching of brackets to bands to make the bracket more resistant to the forces of mastication.
The orthodontist must meanwhile pay close attention to the labiolingual distortion of bracket position and remove and recement or replace unusually distorted bands. Clues to this problem are: unexpected abnormal tooth positions, difficulty in tying ligature ties and, of course, observation of the bracket itself.
Archwire distortion
It is well to remove archwires at intervals whether they need it or not because archwires, especially light archwires, tend to distort with prolonged use (Fig. 5). Distortion can be bitten into the arch by the opposing teeth. Also a high pull headgear can flare out the posterior ends of an upper archwire and that is something to watch for.
Loss of ligature tie
A tooth that has lost a ligature tie can wander from alignment. This is especially true of a tooth that carries an uprighting spring (Fig. 6). The spring action tends to throw the tooth away from the arch and tip it lingually. One should not neglect to tie these teeth and to make the ties secure.
Palatal swelling
Sometimes a patient will complain of swelling palatal to a molar band (Fig. 7). Pay attention to them. They can become large swellings with destructive infections. Sometimes warm salt water rinses will take such a swelling down. If it does not, or if the swelling is large to start with, remove the band and leave it off for a week or two. Do this even if the band is not loose and even when you cannot find an obvious cause for the swelling. Quite likely it is due to food lodged deep in the gingival crevice. Removing the band and leaving it off in this way invariably solves this problem.
Archwire protruding distally through the buccal tube
Often, as space closure proceeds, the archwire will rapidly extrude out the distal end of the buccal tube. In doing so it may impinge on the next tooth or on the gingiva (Fig. 8). The worst feature of this is that it stops the space closing action. It should be one of the first things to check if space closure has slowed or stopped. If this is not present under those conditions, look next for distortion in the archwire that can stop this kind of movement. Failing these, the patient is probably not wearing his space-closing rubber bands.
Space closure with elastic thread ligature
When you have an uncooperative patient who will not wear his elastics, a helpful procedure to assure space closure is to tie elastic thread ligature horizontally within the arch usually from the buccal tube to the elastic loop. This can be fraught with danger if the patient loses the ligature ties on the bicuspid teeth (Fig. 9). The elastic thread ligature keeps working and the bicuspids get squeezed palatally. In the case shown the elastic thread ligatures were removed and the case was dismissed for three weeks. It "relapsed" to a normal relationship in that time.
