In some individuals, the lower jaw is more prominent that the upper jaw. This may be because the lower jaw is larger, or positioned more forward compared to the upper jaw. Since the lower jaw carries all the lower teeth, the lower front teeth may be carried so far forward that they bite in front of the upper front teeth. When this happens, the front teeth will not be able to bite efficiently. If the lower jaw is too prominent (mandibular prognathism), jaw surgery may be required to correct the deformity.
See also: lip prominence