I would like to sure with you today this article published by Confectionerynews.com about the effect of sugar free gum on gingivitis. In particular the study mentions xylitol and maltitol gums, not gums with other bulk sweeteners.
This is the link to the article: Gingivitis and chewing gum
and this is the link to the clinical study itself: International Journal of Dental Hygiene
One more study to add in the list of oral care benefits of the chewing gum.
Chewing Gum Consultant 