Teeth can become crowded for a variety of reasons. There can be a genetic mismatch between the size of the jaws and size of the teeth, jaws too small and teeth too big. Premature loss of the primary (baby) teeth can result in unwanted tooth movement to crowd adult teeth. Dental decay of the primary teeth can cause a reduction in their size, leading to a loss of space needed for the adult teeth resulting in crowding. Extra teeth and transposed teeth can also be causes of crowding.
Spacing between teeth is a less common occurrence than crowding. A genetic mismatch between the size of the jaws and size of the teeth, jaws too big and teeth too small will lead to dental spacing. Congenitally missing teeth, peg shaped teeth, trauma, and functional abnormalities such as tongue thrusts and finger sucking habits can result in dental spacing.
This type of malocclusion is characterized by a protrusion or jetting forward of the upper front teeth. It is often incorrectly referred to as an overbite. If the upper jaw grows forward to excess or lower jaw growth is deficient, an excessive overjet will occur. A thumb sucking habit or forward thrusting tongue pattern can result in an excessive overjet. Dental crowding, extra teeth in the upper jaw or missing teeth in the lower jaw can also cause this type of malocclusion.
NEGATIVE OVERJET OR PROGNATHISM
This bite related upset occurs when the lower front teeth bite forward to the upper front teeth. Excessive forward growth of the lower jaw, deficient growth of the upper jaw, missing upper front teeth and extra lower front teeth are all possible causes of negative overjets.