Many people are confused about what the use of elastics is in orthodontry, what those little rubber bands do, why they are there, and most folks in their early teens are convinced it is done for the sole purpose of making their smile even uglier than it currently is with a bunch of metal attached to it. Fortunately for them, this articleexplains clearly and concisely why orthodontists choose to use elastics and in what positions they can be used.
Elastics basically work like an extra bracket. Because they exert force, they are generally used to push teeth in directions that brackets may not be able to. They are usually hooked into at least two teeth, but up to as many as four at a time, and exert force on the teeth they are hooked into, pulling them in the direction they need to be pulled in, and sometimes pushing them back as well. The many different configurations are listed and illustrated as well, so in case your rubber band gets dirty or brakes you can use the article as a diagram for putting your elastic back on. And another thing, it turns out from this informative article that the bands are not rubber at all! They are usually latex, but latex free varieties exist for those with latex allergies. Latex is however extremely good, as it is thicker than rubber and pulls more strongly, thus making the treatment time shorter.
There is a wonderful analogy in this article that I would like to paraphrase. When explaining about the reason for the use of these elastics, he mentions that they are to be used all the time, except when eating and brushing teeth. This is mentioned explicitly, and the use of these elastics is likened to pushing a car up a slope. The more you push, the quicker it will be up the slope, but if you do not push not only will it not go up, it will start to roll back down! That is exactly the case with orthodontry. The teeth that are crooked are “programmed” to be in the position that they are in, and if not continually pushed will start to revert back to their original position.
The most important thing mentioned is one that we constantly mention with regard to orthodontics. It is that you should not buy elastics on your own, you should only use the ones given to you by your dentist, and you should not, on a whim, buy less or more strong elastics, or ones with a different length. This may seem obvious to the more sensible readers out there, but you have no idea how many people self diagnose based on wikipedia articles, and end up hurting themselves. Please only use these elastics if and as prescribed by your orthodontist!