🦷 Why Does Teeth Sensitivity Occur? Teeth sensitivity happens when the protective layers of your tooth wear down, exposing the inner layer (dentin), which contains tiny tubules connected to the nerve. When hot, cold, sweet, or acidic foods touch this exposed area, it sends a quick, sharp pain. Common Causes: Enamel erosion – From acidic foods, soft drinks, aggressive brushing, or grinding teeth. Gum recession – Gums pull back, exposing the root surface (which has no enamel).