Front teeth wear for a variety of reasons:
1. Natural attrition with aging – Firm and abrasive foods will gradually wear our teeth during our lifetimes. Live long enough and you can see wear on the edges of front teeth.
2. Damage to the TMJ’s – If a person receives a severe blow to the chin, the lower jaw is forced backward. This can compress the head of the bone that forms the lower portion of the Temporomandubular Joint. If the trauma causes damage to this portion of the bone, then the height of the bone decreases. This decrease height affects how the lower teeth fit with the upper teeth and the entire lower jaw pivots backward and upward around the last molar. This results in an opening between the front upper and lower teeth due to simple geometry. In order to regain contact with the teeth, the entire lower jaw has to be positioned forward and will cause the lower front teeth to bang against the upper teeth causing severe wear. So when you see severe wear on the front teeth, suspect damage in the TMJ’s.
3. Parafunctional habits – People chew on all kinds of nonedible things such as pens. Do this often enough and the front teeth will wear down.
4. Trajectory of the lower jaw moving forward against the base of the skull – If the upper portion of the TMJ is more flat than vertical, then the lower jaw will be directed forward. The front teeth are on the other end of the same bone, and all parts of the bone move in the same direction. If the bone moves horizontally and the lower front teeth are directed directly into the upper teeth with significant force. Over time the teeth wear down.