Often it is very obvious where the piece is missing from, as it can be very sharp on the cheeks or tongue. The tooth may or may not be sensitive.
A piece of tooth is missing.
This can be a result of a crack or split developing within a tooth which has been weakened due to decay or a very large filling.
If an entire point (cusp) of a tooth is missing, a more solid filling material made of ceramic can provide the strength and rigidity needed. This is called an onlay.
If the tooth is very badly broken (but hasn’t cause problems to the nerve yet), a crown can be used to rebuild and support the left over tooth structure.
The internal part of the tooth is very porous, with many little channels that communicate to the nerve. Bacteria can enter these channels and over time, result in the death and infection of the tooth.