Dental cleanings are important to keep your body and smile healthy.

Dental cleanings are important to help prevent and maintain gum and bone disease.  If you are at high risk for gum/bone disease then not coming in for regular cleanings can cost you your teeth, as there is little to no pain in losing the bone around your teeth.  Dental cleanings are done regularly to remove all hard and soft deposits off the teeth. If these deposits are not removed from the teeth, this will cause inflammation (swelling and increased blood flow) in the mouth. 

Dental cleanings help to maintain your overall health.

Having your teeth cleaned regularly will help keep your bone healthy and allow you to maintain better overall better general health as well.  Many diseases are correlated with bone disease (try googling periodontal disease and general health). During the dental cleaning, the dental hygienists or dentist may also find cavities that are hiding under the gums or between the teeth.