When the bacteria or toxins from your decay has progressed through the hard enamel and into the soft nerve of the tooth, and the nerve has started to react and become a tooth ache.
If your nerve is already dead you may get an infection or absess which can also cause a significant amount of pain.
What causes a tooth nerve to die apart from decay?
The main reasons you might need root canal therapy is:
- Decay or infection
- Trauma or a knock to the teeth
- Grinding or clenching
- Cracked or broken tooth