A crossbite is an orthodontic disorder in which the top teeth rest on the inner side of the lower teeth instead of resting slightly outwards. Crossbites are more common with teeth located at the sides. Crossbites should be treated early while the jawbones are still expanding. These bones fuse at around 16 years for girls and 19 years for boys. Problems caused by crossbites include gum disease, bone loss, difficulty in chewing, jaws losing symmetry, etc. If a single tooth is affected by crossbite, the orthodontist treats it with braces. For multiple teeth, jaw expanders are used to reduce crowding between teeth.
An open bite is a condition in which the top front teeth do not come in contact with their opposite teeth. When a person affected by this condition closes his mouth to bite, it is possible to see inside his mouth because the upper and lower front teeth do not meet. Genetics, thumb-sucking, and lisping can cause an open bite. Treatment for open bite involves surgery on the upper jaw. The patient is made to wear braces for a few months before the surgery. Typically, treatment for open bite can take between one-and-half to two years.
Overbite is a common orthodontic condition also known as buck teeth. In this condition the top teeth overlap the lower teeth. Genetics and actions such as thumb-sucking and pencil-chewing can lead to overbite in children. When children repeatedly thrust their tongue against the back of the top teeth while swallowing, it pushes the teeth out. Children affected by overbite can hurt their protruding front teeth easily. The lower teeth may hit the root of the upper teeth when chewing.
Till the age of nine children should be treated with a functional appliance that helps the lower jaw to develop properly. After this, the child should wear braces till the lower teeth come together and the upper teeth are pushed up.
Overjet is a condition in which the upper front teeth protrude too far ahead of the lower teeth. Overjet can happen if the molars are not properly aligned, the bones of the upper and lower jaw are not balanced, upper incisors flare and come out, lower teeth are missing, or from thumb sucking. The risks of not treating overjet include injury to the protruding front teeth, uneven jaw growth, and teeth may wear out early. In the first stage of the treatment overjet is treated with braces to align the teeth.
Coils, springs, and headgear are used in the second stage to push back the front upper teeth and push out the front lower teeth.
In an underbite the lower front teeth extend outwards. The medical term for underbite is prognathism. An underdeveloped upper jaw and overdeveloped lower jaw are characteristic features of an underbite. It can be caused by excessive thumb sucking, nasal obstruction, and tongue thrusting. If not treated, an underbite can lead to poor functioning of the teeth and digestive problems. Underbites can be treated without surgery until the patient reached puberty; therefore an early diagnosis is critical. Orthodontists will try to modify jaw and teeth growth using headgear and braces.
Treatment done at a later stage involves teeth extraction and surgery to correct the structure of the jaws.