What you see inside your mouth right now is not your entire tooth. The pearly-white part your see is called the tooth’s crown, and below the gums are the roots. Roots extend well into your jawbone and each tooth has up to 4 roots.
Within each root is a root canal, this hollow space runs vertically from the inside of the crown to the tip of the root. Nerves and blood vessels from within the root canal supply your teeth with responsiveness and nutrition, helping them stay healthy.
Therefore, each tooth is connected to the nervous system and our body’s circulatory system. So, if a tooth root becomes decayed and filled with bacteria, then the bacteria will either: travel in the blood and throughout the rest of your body or pain will travel to the nerves in the brain, resulting in toothaches.