Xylitol reduces decay-causing bacteriaSugar-free gum sweetened with xylitol has the added benefit of inhibiting the growth of Streptococcus mutans, one of the oral bacteria that cause cavities. In the presence of xylitol, the bacteria lose the ability to adhere to the tooth, stunting the cavity-causing process. With xylitol use over a period of time, the types of bacteria in the mouth change and fewer decay-causing bacteria survive on tooth surfaces.
To chew or not to chewAlthough chewing sugar-free gum can be beneficial in most instances, there are some cases in which chewing gum is not recommended. For example, if you are experiencing any type of jaw pain or temporomandibular disorder symptoms (TMD/TMJ), you should refrain from chewing gum and talk to your dentist about what options are available to you.
For most people, chewing sugar-free gum (especially gum sweetened with xylitol) can be a good preventive measure in situations when toothbrushing and flossing aren't practical, but sugar-free or not, chewing gum should never replace good dental hygiene practices.
Source: Delta Dental