Root canal treatment is needed when the blood or nerve supply of the tooth( tooth pulp) is infected through decay or injury. You may complain of an existing pain or in early stage of infection even not feel any.
In some cases, your tooth could darken in colour (which may mean that the nerve of the tooth has died or is dying). The infection may spread through the root in bone & lead to an abscess if left untreated.
The aim of the treatment is to remove all infection from & fill the root canal to prevent any further infection, as a dead tooth is more brittle, it may be necessary to restore the tooth with a crown to provide extra support and strength to treated tooth.
Root canal treatment is routine but skilled and time-consuming procedure & in most cases will involve two ( or sometimes more) visits.
Root treatments on back teeth can be more complicated mostly because they have a number of roots & multiple canals.