If the root canal becomes infect then the pulp (the soft tissue that contains the nerves and blood vessels will begin to die). When this happens the bacteria will continue to spread down the rest of the root canal at an alarming rate.
This can cause the gum tissue surrounding the root canal to become red and swollen. Infections in the root canal can even make your face swollen. This is known as Dental Abscess.
How does a Root Canal Infection Spread
If left untreated, bacteria can spread rapidly in the mouth. This causes the infection to worsen. As the infection spreads it usually becomes more painful so it is strongly advisable that you seek out medical help as early as possible.
Although it is important to maintain a good level of oral hygiene, doing so will not fix the problem. It is essential that you book an appointment to see the dentist who will clear the bacteria out your pulp using a Root Canal procedure.