Whether or not a root canal is needed depends on the specific infection, if the tooth does not hurt but is infected to the pulp it is usually recommended that a root canal is needed.
Root canals are often used to treat cases of pulpal necrosis and root infections, and some patients may experience adverse symptoms such as swelling and pain after root canal treatment.
Root canal treatment is usually recommended when the infection reaches the pulp. Some patients with chronic pulpitis or chronic periapical inflammation may not have tooth pain, but if left untreated it may lead to more serious conditions such as widening of the inflammation and apical cysts, in which case root canal treatment is usually recommended.
If the disease is diagnosed, early treatment is recommended to minimize the adverse effects of the disease.