Tooth sensitivity is caused when dentin (softer part of the tooth that lies under the tooth enamel) is exposed. For some, it is not just sensitive, but very painful. Some causes may be receding gums, gum disease, teeth grinding, brushing too hard, poor diet or poor oral health care. Some triggers may be eating or drinking cold, sweet or hot foods and beverages and/or breathing in cold air. If you have sensitive teeth be sure to visit your dentist or dental hygienist for more information and the proper treatment.