Braces are used to correct improper bites which are called malocclusions
Overly crowded teeth: This occurs when there is simply a lack of room within your jaw for all of your teeth to fit normally. When left untreated, overly crowded teeth can cause dental decay, an increase in chances of gum disease, and can prevent the normal function of teeth.
Widely spaced teeth: This occurs with abnormal continued growth of the jaw bone. When teeth are missing, this issue can also be caused by the other teeth shifting due to extra space. Spacing issues in teeth can cause some periodontal diseases.
Crossbite: This occurs when the upper and lower jaws are both misaligned. It causes one or more upper teeth to bite on the inside of the lower teeth, and can happen on both the front and/or the sides of the mouth. This issue can cause wear of the teeth, gum disease, and bone loss.
Overbite: What people commonly refer to as an "overbite" is known to dental professionals as "overjet." It occurs when the upper teeth bite over the lower teeth. It's typically caused by either genetics, bad oral habits, or over development of the bone that supports the teeth. This issue can lead to gum problems or irritation, and/or wear on the lower teeth and can cause painful jaw and joint problems.
Underbite: This occurs when the lower teeth protrude past the front teeth. It's usually caused by undergrowth of the upper jaw, overgrowth of the lower jaw, or both. It can also be caused by
missing upper teeth. This issue can prevent the normal function of front teeth or molars which can lead to tooth wear. It can also cause painful jaw and joint problems.