Orthodontics is the correction of tooth alignment and bite problems. A perfect smile should consist of straight teeth without gaps and overlaps and the top teeth should align with the bottom. In some cases, misalignment can happen due to injury, but most often the teeth and mouth are growing at different speeds. 
Appliances, such as braces and retainers, are used to put pressure on your teeth and jaw forcing them into an aligned form. Orthodontic treatment can occur at any age, although dentists recommend starting the process while the child is still growing. On average, treatments tend to take two and two and a half years, and you are expected to see your dentist once a month to carry out necessary adjustments.
