How does a dentist determine whether tooth extraction is necessary for crowded, overbite and overjet teeth?

There are 3 main reasons to consider extractions in the treatment of crowded teeth.

1. The crowding is too severe to be corrected with IPR (interproximal reduction: sandpapering the teeth to make them slimmer) or arch expansion.
2. The patient has bimaxillary protrusion of the soft tissues (lips) and incompetent lips (lips that cannot meet without actively straining).
3. The patient has an underlying skeletal discrepancy.

• If the upper jaw is too large/the lower jaw is too small (class 2), then upper extractions may be considered as camouflage.
• If the upper jaw is too small/the lower jaw is too large (class 3), then lower extractions may be considered as camouflage.

Overjet (how far the upper incisors are from the front surface of the lower incisors) and overbite (how much the upper and lower incisors overlap in the maximum biting position) are NORMAL features of occlusion that should be present in ALL humans. Orthodontic treatment merely optimises this (reducing a large overjet or reducing a deep overbite, for example) but cannot eliminate overbite or overjet!