Can sugar free gum with xylitol help prevent cavities or gingivitis?

Yes: Xylitol inhibits tooth decay, the chewing of the gum increases saliva flow ( saliva buffers the mouth and reduces decay). Also the mechanical action of chewing helps dislodge food debris.One word of caution xylitol is toxic to pets.

Xylitol: Oral bacteria do not metabolize xylitol efficiently, so almost no acid is produced. “also, regular chewing with xylitol gum stimulates the production of saliva—nature’s own mouthwash, which also reduces cavities.”.

Research: Research has shown that it can help with cavities, but I am not sure about gingivitis. Don;t get the idea that chewing this gum only will work as your preventative magic bullet. Superb oral hygiene is still the gold standard. I would do more research on this subject.