Sensitive teeth occur when the enamel, the protective layer on teeth, wears down or when gums recede, exposing the underlying dentin. This can lead to discomfort or pain when consuming hot, cold, sweet, or acidic foods and drinks. Common causes of sensitive teeth include tooth decay, gum disease, and aggressive brushing. People with sensitive teeth may benefit from using special toothpaste designed for sensitivity and should consult a dentist for proper diagnosis and treatment options.