MODEL RELEASED. Tooth pain. Man wincing in pain after eating ice cream. Teeth may be sensitive to hot or cold temperatures if the tooth enamel has been worn down or the gums have receded. This causes minute tunnels in the dentine (the layer beneath the enamel) to be exposed, which lead to nerves in the pulp cavity. Tooth sensitivity can be reduced by using a desensitising toothpaste, or by having a sealant applied to the teeth by a dentist.