Lost fillings are common and are generally not classified as emergencies. However, sometimes, losing a filling can be painful because the tooth underneath the filling is often sensitive or may be subject to further decay. If you lose a filling make an appointment to see your dentist as soon as possible. Delay may cause more harm.
Fillings can come loose for a number of reasons. In many situations, the tooth underneath the filling decays and part of it is destroyed. When this happens, the original filling no longer has a tight hold on the tooth and can fall out. Other possible reasons are trauma, grinding and clenching.