When do you need a filling?
Decay often starts without pain, which is why many cavities are found at routine check-ups or on X-rays before you notice anything. Signs that a filling may be needed include sensitivity to sweet or cold, a rough edge your tongue keeps finding, food catching between teeth, or a visible dark spot. Old fillings may also crack, leak or develop decay underneath. Treating a cavity early usually means a smaller, simpler filling; left untreated, decay can reach the nerve and lead to root canal treatment or even loss of the tooth.