Upper Front Teeth Protrusion
Commonly known as "buck teeth," protrusion of the incisors is a result of improper angulation of the teeth as they relate to the jaw. When the top jaw is in front of the bottom jaw, the lower lip will often rest underneath the top incisor teeth and cause them to flare forward. Habitual sucking of the thumb can also cause the front teeth to protrude. Protruded teeth are more prone to damage from facial trauma because of their prominent position within the face.
Overbite is when the top front teeth vertically overlap the bottom front teeth. In severe cases, the lower teeth can be completely behind the top teeth so they cannot be seen when teeth come together. When this happens, the lower front teeth will bite against the gums in the palate instead of the top front teeth. This can cause irritation and inflammation on the roof of the mouth.
The top teeth are meant to form a perimeter around the bottom teeth much like the lid of a shoe box forms a perimeter around the shoebox. Cross bite occurs when a top tooth or several top teeth are biting on the wrong side of the lower teeth (toward the tongue). This is often a result of a narrow or small upper jaw. A cross bite can cause the jaw to function in a compromised position leading to abnormal development of the jaws and teeth.
The inability to touch front teeth together when the back teeth bite is called an open bite. Open bites are often associated with thumb and finger sucking habits. Open bites are also common in people who predominantly breathe through their mouth. Because of the open bite of the teeth, patients habitually thrust the tongue forward to seal off the oral cavity while swallowing. This results in a "tongue thrust" habit. Open bites also cause problems with chewing. The inability of the front teeth to touch makes it impossible to incise foods, such as meats and lettuce in a sandwich or a piece of pizza. Another functional consequence of an open bite is the inability to say certain sounds such as "S" and "Z" sounds which results in a lisp.
Crowding is the reason that teeth are crooked. Because the jaw bones are not large enough to accommodate all of the teeth, the teeth compensate by coming in the mouth in a rotated position that does not take as much room. Most of the time, crowding can be resolved by expanding the jaws so that teeth do not have to be pulled out.
Spacing occurs when the jaw bones are large, the teeth are small or some combination of the two. It is not uncommon to see gaps between the front two teeth. Spacing is also a problem when a tooth is missing. Orthodontic treatment can close spaces very efficiently
Dental Midlines not Matched
When dental midlines do not match, it is usually one of two problems:
- The bite on one side of the mouth is incorrect
- There is more crowding on one side of the mouth than the other
In either case, it is important to be evaluated by an orthodontist to understand the consequences of a midline discrepancy.