A root canal treatment is done to save a tooth that is badly damaged or infected. During this treatment, the dentist removes the soft tissue and nerve from inside the tooth, cleans the inside very carefully, and then seals it to stop bacteria from getting back in. Without treatment, the infection can spread deeper into the tooth and the area around the root. This can cause a lot of pain, swelling, and in some cases an abscess.
The root canal is the small space in the middle of the tooth. Inside this space is the pulp, which is the soft tissue that contains nerves and blood vessels. When a tooth is still growing, this tissue helps it develop. But once the tooth is fully grown and has come through the gums, the nerve is no longer needed for the tooth to keep working properly. Its main job after that is only to feel things like hot and cold.
This means that a tooth can still do its normal job even after the nerve has been removed. With a successful root canal treatment, the tooth can often be kept for many years instead of being taken out. In other words, the treatment is meant to remove the infection, stop the pain, and help you keep your natural tooth.