Tooth sensitivity happens when the protective enamel wears thin or the gums recede, exposing the tiny tubes that lead to the nerve. Common culprits include hard brushing, acidic foods, grinding, and untreated cavities.
A desensitising toothpaste, a softer brush, and easing off acidic drinks help many people within weeks. If the pain is sharp or limited to one tooth, though, it may signal decay or a cracked tooth that needs a professional look.