Depends on the gum. It has been shown in studies that chewing gum does help remove some of the plaque which accumulates on our teeth. That’s obviously a good thing. Part of the reason is the gum shoves the plaque off parts of the teeth but a greater benefit is the stimulation of saliva which neutralizes some of the acid in plaque and rinses it away. However, “four out of five dentists” recommend sugarless gum for obvious reasons. ( I’ve always wondered who those fifth dentists are and where they went to dental school?)
There is, however, really good evidence that gum with Xylitol (a natural “sugarless” sweetener) will dramatically reduce new cavity formation. It also seems to reverse decay already present. Bacteria metabolize sucrose (the standard sweetener in most gum and candy) into an acid compound as does sorbitol (a sucrose-free sweetener) although it produces less acid.
Xylitol is not metabolized by oral bacteria very well, and virtually no acid is produced. A University of Michigan Study in the 1990’s compared 1227 public school kids in Belize for over three years. They were 9 to 11 years old and their teachers supervised the use of gum three to five times a day. The gums were sweetened with either sucrose, sorbitol or xylitol. One group of kids went without any gum.
Dentists examined all of the kids before the study and again at 16, 28 and 40 months. At 28 months the group who chewed the xylitol sweetened gum did not develop new cavities. They also had re-mineralized some old cavities. The sorbitol group showed an increase in cavities. The kids who were without gum, had a higher rate of cavity development and the sucrose group showed the highest increase in cavities. Another study by the same group on 6 year olds showed even better results.
So I would recommend gum-chewers get the xylitol sweetened variety. Maybe then we can get those one out of five dentists on board with the rest of us.