Endodontic treatment means treatment inside of the tooth. Root canal treatment is a type of endodontic treatment. The symptoms of root canals includes pain, prolonged sensitivity to heat or cold, tenderness to touch and chewing, discoloration of the tooth, swelling, drainage, formation of dental abscess and tenderness in the lymph nodes as well as nearby bone and gum tissues.
In the early stage of infection, you may not feel any pain at all.

During this procedure the endodontist removes the inflamed or infected pulp to prevent it from spreading, carefully cleans and shapes the inside of the root canal, then fills and seals the space. Pulp capping is an alternative to root canals that are used when the infection has not penetrated the pulp.
Pulp capping do prevent a large dental filling from getting too close to the nerve.