Yes it’s true that chewing sugar-free gum can help prevent cavities.  Keep in mind however that it is not meant to replace brushing and flossing.  It is only meant as an adjunct to proper home care which consists of brushing twice and flossing at least once daily.

Most people brush in the morning and at night, and a smaller group will brush a third time, usually after lunch.  No time to brush after lunch?  Chew sugar-free gum instead.  Chewing increases saliva flow which helps to cleanse the teeth.  An increase in saliva also helps to buffer the acidity that occurs after eating, and it is the acidity that weakens the teeth and promotes formation of cavities.  In addition, the gum will help pull out food particles that may be stuck between teeth or in the crevices of the biting surfaces.

Sugar-free gum contains xylitol which is a sugar substitute.  Unlike sugar, Xylitol is non-fermentable and therefore cannot be converted to acids by oral bacteria.  Some brands that contain xylitol include:  Trident, Dentyne, Orbit, Eclipse, Extra

As with anything else, moderation is key.  Chewing gum all day can lead to other problems such as TMJ pain and jaw muscle fatigue.  Likewise people who already have TMJ problems should limit their use of gum, as their condition will worsen with the constant jaw movement of chewing gum.

Interestingly, I just read that xylitol can be toxic to dogs.  So keep your sugar-free gum out of reach of your dogs.  But I digress… for more info on that, please consult your veterinarian.

Your friendly dentist,
Dr. Sarah Po
www.elitesacramentodentist.com
January 21, 2010

Sources:
http://jada.ada.org/cgi/reprint/129/11/1623.pdf
http://xylitolhealth.com/oral_health.html