He said vibrations caused by drilling for ordinary fillings could damage the nerve and cause root canal work later in life.

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The tooth needs to be drilled into, right down to the bottom of the nerve-carrying canal that runs through the root.

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But to reach the physiological root of those sensations, we need to take a close look at the vagus nerve -- actually a bundle of nerves that starts at the base of the brain and branches out through the body, linking up with the facial and vocal muscles and the heart, lungs, and gut.

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