Deep cavities:: Caries are a bacterial infection of the tooth. If this infection has reached the root canals, the resulting inflammation of the pulp will cause a bad toothache. Only endodontic (root canal) treatment can now stop the bacterial infection and save the tooth.
Dental fractures: In a fractured tooth, root canals may get exposed to the outside
and are at high risk of bacterial infection. A root canal treatment may then be part
of fixing the tooth.
Revision treatments: Sometimes, a past endodontic treatment may not have been
entirely successful: Over time, tiny amounts of bacteria left in the root canal
system may multiply, escape from the root tip into the surrounding tissue and
lead to chronic inflammation. In such a situation, a revision treatment – another
attempt at cleaning and disinfecting the canals – is the only alternative to losing