• When the upper front teeth appear protruded it is usually due to the lower jaw being shorter than normal.
  • This can also be due to a thumb or finger sucking habit that gradually tips the upper front teeth forward and the lower front teeth back.
  • The upper front teeth are usually only 1 to 2 mm ahead of the lower front teeth (normal overjet).
  • When the upper front teeth are further ahead of the lower front teeth than this, there is excessive overjet.
  • In cases where this excess overjet is severe enough the lower lip can rest between the upper and lower front teeth in what is called a lip trap.
  • When both the upper and lower front teeth are protruded it is usually due to an anterior tongue thrust where the rest position of the tongue is pushing against the front teeth.
  • This constant low pressure against the front teeth gradually pushes the front teeth forward and it is common for spaces to occur between all the front teeth.
  • In some cases the front teeth tip forward so much that they no longer touch or overlap at the front, which is called an anterior open bite.
  • The tongue posture that causes this protrusion of the upper and lower teeth is a kind of orofacial myofunctional disorder.