The pulp is a thread like structure present in the root of the tooth. When it gets diseased or injured, the pulp tissue dies. If it is not removed , it causes infection in the tooth which leads to severe pain. This can in turn lead to a dental abcess. Hence a root canal treatment is performed wherein the pulp is removed, the root canal is disinfected and a sealant is used to protect it. A crown is generally advised over this tooth to make it functional again.
Instrument fracture reduces the success rate of root canal treatment. hence fractured instrument should be removed.