Dental Tooth Fillings are used when damage to the tooth does not compromise the structural integrity of the tooth or its health. The filling is a plug (often in the form of plastic like resin), which prevents germs and debris from entering the tooth.
Fillings are a way to restore a tooth damaged by decay, back to its normal function and/or shape. Before a Filling is applied, the removal of the decayed tooth material, cleaning of the affected area and filling material is required. Fillings prevent further decay by closing off the area/space where bacteria can enter.
In the case where a dental tooth filling may be very large, there is more likely the loss of the structural integrity of the original tooth and in which case the Dentist may recommend a Crown.