Molars and premolars that have had root canal therapy ought to be secured with a crown that covers the cusps of the tooth. This is because the access made into the root canal framework expels a significant amount of tooth structure. Molars and premolars are the primary teeth utilized in chewing and will almost certainly fracture later on without cuspal coverage. Anterior teeth typically don't require full coverage restorations after a root canal procedure, except if there is broad tooth misfortune from decay or for esthetics or unusual occlusion. Therefore, it is important to have regular X-rays taken of the root canal to guarantee that the tooth is not having any issues that the patient would not know of.
Placement of a crown or cusp-protecting cast gold covering is prescribed also because these have the best ability to seal the treated tooth. There is insufficient proof to assess the effects of crowns compared to conventional fillings for the restoration of root-filled teeth, decision of restoration ought to depend on the clinical experience of the practitioner and the inclination of the patients. Endodontic treatment may fail for many reasons: one common reason for failure is inadequate chemomechanical debridement of the root canal. This may be because of poor endodontic access, missed anatomy or inadequate shaping of the canal, particularly in the apical third of the root canal, also because of the trouble of reaching the accessory canals which are minute canals that stretch out in from the pulp to the periodontium in a random direction. They are for the most part found in the apical third of the root.
If the tooth is not impeccably sealed, the canal may leak, causing eventual failure. Also, many people accept once a tooth has had a root canal treatment it cannot further decay. This is not valid, be that as it may: a tooth with a root canal treatment still has the ability to decay, and without appropriate home care and an adequate fluoride source the tooth structure can turn out to be seriously decayed (often without the patient's information since the nerve has been evacuated, leaving the tooth with no pain perception). In this way, non-restorable carious destruction is the main reason for extraction of teeth after root canal therapy, accounting for up to 66% of these extractions.