The tooth has three layers- Enamel, dentin and pulp. Whenever the decay becomes deep and extents till the pulp, the patient will start experiencing sensitivity and pain. In such conditions, the treatment done will be root canal treatment. The treatment includes filling till the root end. The treatment includes one or two appointments based on the infection in the root end. The procedure involves removal of decay, opening of the pulp and root region to remove infected tissues and cleaning with suitable medicaments. After the region is completely sterile, the root canal is filled with inert material and the opening is filled with a restorative material. In cases of minimal infection, the treatment is finished in single appointment. Multiple appointments are preferred in cases of infection. After completion of the root canal treatment, a crown needs to be placed over the tooth for added strength to the tooth. When there is weakened tooth structure, the tooth is reinforced using posts and core.