Erosion is the loss of the surface of the tooth
Especially the enamel - caused by acid attack. This is different from bacterial acid attack which we call tooth decay. Enamel is the hard outer surface of the tooth seen when we smile and it protects the sensitive dentine underneath. Erosion of the enamel can lead to exposure of the dentine, which may lead to pain and sensitivity with cold foods and drinks.
Erosion is a slow process which people generally do not become aware of until significant enamel is already lost. Erosion often shows up as hollows on the top surface of the molar teeth or the teeth seem to become smaller or thinner as the enamel erodes away. As the enamel wears away exposing the underlying dentine the teeth may appear a darker yellow colour - the colour of the dentine - and sensitivity to hot, cold or acidic foods and drinks can become painful.