Root canal treatment.
If decaying process is at an advanced stage when it has already affected neurovascular fascicle (the so-called pulp), root canal therapy is unavoidable. It involves the removal of the pulp and further sealing of the root canals. The success of the treatment in this case depends on the quality of the root canal sealing.
Nowadays when defining the depth of the canal a doctor deals with the magnitudes of 0.5 mm in this or that direction. The only way to ensure the doctor and the patient that a pulpless tooth will perform its functions for many years without troubling the patient (and the doctor as well) is pinpoint accuracy of medical manipulations. Taking into account the fact that modern technologies make it possible to repeatedly (virtually indefinitely) change overage old and worn-out prostheses and fillings, it is crystal clear why it is so important to have a good, solid "foundation" (a skillfully sealed root canal).
Unfortunately, there are a lot of cases when either because of a patient, who hasn't timely consulted a dentist, or because of the low-quality root canal treatment a patient has received earlier, a patients starts to feel dull pain, the tooth aches when a patient takes a bite with the tooth, becomes slightly sensitive to the cold, a patients feels as if the tooth is growing, there is characteristic smell and other periodontitis, i.e. tooth pulp inflammation.
There should be no rush in taking such tooth out because modern root canal treatment can offer a whole range of drugs and methods which allow treating and preserving even teeth which were classified by the 20-th century dentistry as hopelessly damaged. In no event does it mean that dentists can save any tooth root at an advanced stage of root canal damage, but it should be emphasized once again: don't rush to take such a tooth out, there will always be time to do that.