The short answer is that “bands,” also called elastics or rubber bands, help correct jaw alignment or the “bite.”  Misalignment can happen as a discrepancy between the upper and lower jaw and cause problems from chewing and excessive tooth wearing to jaw pain.  The elastics can be configured in several different “shapes”  to address varying bite issues throughout treatment. In addition to configuring elastics, the elastics themselves come in a variety of sizes and strengths that help in the fine tuning of the smile and fit of the teeth. 
Although elastics may seem simple, there is quite a bit of science and reasoning behind each patient’s elastic prescription that the orthodontist weighs carefully. It is a mistake to think that doubling up on bands, without your orthodontists recommendation, will speed up your treatment.  It may even do the opposite.
One unique and important aspect of orthodontic elastic bands is that it’s the patient’s part to successful treatment.  Choosing to be diligent in wearing your elastics results in a more efficient treatment and the opposite is also true. “Simply put, not wearing your bands can prolong your time in braces,” Tammy Curless, Lead Orthodontic assistant said.
So remember, when it comes to your braces, elastics are your part in getting your teeth perfect. Always wear them as recommended and you may find that you save yourself a little (or a lot) of time in braces which means more time showing off that smile braces free!