Orthodontic problems generally result in a “malocclusion”, which literally means “bad bite”.
A malocclusion is when the teeth do not fit together properly due to improperly growing jaws, and/or improperly positioned teeth.
This can be due to a great number of factors including crowded teeth, spaced teeth, crooked teeth, extra teeth, missing teeth, early loss of baby teeth, impacted teeth, cleft palate, thumb or finger sucking habits, tongue thrust habit, mouth breathing, trauma, and periodontal disease among others.
There are both genetic factors and environmental influences involved with the formation of malocclusions.
Crooked teeth is the most common reason that people seek orthodontic treatment.
Crooked teeth are usually the result of crowding of the teeth which in turn can be the result of poorly growing jaws, early loss of baby teeth, thumb sucking habit, muscle imbalance and so on.
Although crooked teeth are usually associated with crowded teeth they can also occur with spaced teeth.
Crowding is the most common reason for teeth being crooked.
Crowding can be a result of the jaws not growing large enough for the teeth to fit in. Crowding can also be the result of the early loss of baby teeth that allowed other teeth to shift in a detrimental way.
Crowding can occasionally be due to unusually large teeth.
Crooked teeth as a result of crowding is the most common reason that people seek orthodontic treatment.
Spacing is a bite issue that results in gaps between the teeth.
This can be due to smaller teeth combined with a larger jaw structure. These gaps can also be caused by dental habits such as thumb sucking, tongue thrusting or certain swallowing habits. Spacing can also be the consequence of extracted teeth.
Jaws can be mismatched in a number of ways:
When the lower jaw is too short relative to the upper jaw it will appear that the upper front teeth are sticking out too far. The profile will show a weak or retrusive chin and a convex profile. This is by far the most common mismatch of jaw growth.
When the upper jaw is too short relative to the lower jaw it will appear that the lower teeth are sticking out too far and the profile will show a strong or protrusive chin with a straight profile. This is a relatively rare mismatch of jaw growth. This often results in an underbite or anterior crossbite, where the lower front teeth are ahead of the upper front teeth instead of the other way around.
When the upper jaw is too narrow relative to the lower jaw the side teeth can go into crossbite with the lower teeth on one side or sometimes both sides. The upper side teeth are normally further out towards the cheeks than the lower side teeth. When these side teeth are in crossbite the lower side teeth are further out towards the cheeks than the upper side teeth.
Improper overlap of the front teeth can be in a number of forms:
This is when the upper front teeth are too far ahead of the lower front teeth to fit properly. The upper front teeth are usually around 2mm ahead of the lower front teeth. Excess overjet can be due to a mismatch in the growth of the upper and lower jaws. It can also be from a poor oral habit such as sucking on a thumb or fingers or other objects like clothing or blankets. Such a habit will push the upper front teeth forward and the lower front teeth backwards.
This is when the lower front teeth are ahead of the lower front teeth and it can be due to a mismatch in the growth of the upper and lower jaws. It can also be due to the front teeth growing into the mouth in an unusual angle and once the upper front teeth are caught behind the lower front teeth they will remain that way unless orthodontic treatment is done.
This is when the upper and lower front teeth overlap vertically more than normal. The biting edges of the upper and lower front teeth usually overlap vertically approximately 2mm. When the overbite is deeper that this it can cause problems with the overall fit of the bite and it often results in excessive wear of the edges of the lower front teeth.
It is fairly rare that there are extra teeth but is does occur. One of the most common areas that this occurs is at the second from the centre teeth on the upper teeth. When there are extra teeth it is simply due to genetics and it will cause severe crowding if such an extra tooth is allowed to stay in the mouth. Normally an extra tooth will be removed as soon as is practical. Another common are for extra teeth is at the wisdom teeth (third molars).
Missing teeth are fairly common and often cause considerable difficulty in orthodontic treatment. Teeth can be missing due to loss of the tooth from trauma or decay or teeth can be congenitally missing. The common areas where teeth are congenitally missing are the second from the centre upper teeth (upper lateral incisors) and the lower teeth just before the molars (lower second premolars).
Sometimes the baby teeth can remain in the place of the missing adult teeth but often the baby teeth will fall out and the adjacent adult teeth shift into the gap. The decision must be made as to whether the space of the missing teeth should be maintained for future replacement with an implant or if the space can be closed with orthodontic treatment while providing a normal and functional bite.
If there is a delay in an adult tooth growing into the mouth it could be that the tooth is missing or it could be that the tooth is impacted.
An impacted tooth is positioned in a way that it cannot grow in normally or there is too much crowding for that tooth to grow in normally.
Orthodontic treatment is almost always necessary to successfully bring an impacted tooth into its normal position.
The most commonly impacted teeth are wisdom teeth, which are normally removed. The next most commonly impacted teeth are the upper canines (third tooth from the centre). Occasionally the lower second molars are impacted.
Discomfort or sounds in the jaw joints can be an indication that there is a problem with the bite.
This discomfort or these sounds can also be a result of trauma, stress, muscle imbalance, chiropractic misalignment among many other things.
It is common for people to say they have “TMJ”. TMJ actually stands for temporomandibular joint, which is the joint that connects the lower jaw to the skull and we all have two of these; one on the right and one on the left. When there is disorder in these joints such as discomfort, sounds such as clicking or popping, or actual locking of the TMJs, that person has TMD or temporomandibular disorder.
Sometimes orthodontic treatment can be of benefit in treating TMD and at times other therapies such as chiropractic treatment, physiotherapy, osteopathy or other therapies are more appropriate. Some, but not all, orthodontists provide treatment for TMD.