Since dental pulp inside the tooth is responsible for any stimuli like changes in hot or cold temperature on teeth, sensitivity in one special tooth is because of: 1-weakened and thinned enamel of the tooth. 2-cracks, chips and damages in that tooth. 3- exposure of the root and dentinal tubules to outer irritants 4-inflmmation and infection of the dental pulp in the tooth. 5-other factors.