Gum recession happens to many people, particularly as we age. If you suddenly notice your gums receding or withdrawing from the teeth, it’s very important to be assessed by a dentist. Recession isn’t just an issue of aesthetics; when gums recede, the root becomes exposed. This makes teeth very sensitive to cold and hot and causes discomfort while eating and drinking.
Recession can happen to anyone, even to those who take good care of their teeth (or perhaps too good—overbrushing is one of the causes of recession!) A sports injury, ill-fitting dentures, smoking, periodontal disease, chronic inflammation, and genetic factors can also cause recession. Numerous types of treatments are available to combat recession. It’s best to speak to your dentist if you see any signs.
<http://www.ada.org/~/media/ADA/Publications/Files/ADA_PatientSmart_Gum_Recession.ashx>