Is chewing gum bad for your teeth? (Modified from original post)

This post is in response to Benedict's post. (Didi, I know you will read my post! =D)

Some studies have shown that chewing gum can have an indirect positive effect on your teeth. The actual gum is pretty inert. It isn't digestible and it doesn't promote decay. It does two things. First, it mechanically cleans the surfaces of your teeth as you chew. Second, and possibly the most beneficial, it promotes the flow of saliva. Saliva is a natural buffering agent which washes the teeth and neutralises some of the acid produced by bacteria. It is the acid which erodes enamel and eventually causes cavities. One study showed that after chewing gum for 10 minutes each waking hour for two weeks, participants increased their salivary flow to a functional level and increased salivary pH and buffering capacity.

HOWEVER...

Gum typically contains some type of sweetener which can be harmful to your teeth if these types of gum are chewed to often or are removed from the mouth too soon. In fact, studies have shown that if a person chews gum containing sugar, it should be chewed for at least 15 to 20 minutes. After this time, the sugar is gone, but the saliva is sufficiently stimulated to rinse away some of the sugar residue.

Vogel et al., (1998) found significant increases in pH, free calcium, and phosphate concentrations in plaque and saliva when an alpha-tricalcium-phosphate-containing gum was chewed after a sugary meal. The results of the study suggest that this experimental gum may be more effective than conventional gum in reducing the cavity causing effects of sugar.

One artificial sweetener called Xylitol is proving to be quite beneficial. This ingredient may directly prevent cavities. One study from Finland shows not only a reduction in decay in children who have chewed gum with this ingredient, but extremely small lesions have actually been reversed. The exact mechanism of action of Xylitol is unknown, but it appears to inhibit bacterial growth, including growth of Streptococcus mutans -- the main bacteria implicated in dental decay. Perhaps it causes Streptococcus mutans to lose a competitive edge in the oral ecosystem.

The proper protocol for cavity protection is to chew two pieces of gum three to five times daily for at least five minutes per chewing session. Any less time will decrease the effectiveness of the Xylitol. Xylitol appears to be the only artificial sweetener which is not fermented by Streptococcus mutans, although the other sweeteners are fermented at a much lower rate than sugar.

One eight-week crossover clinical study conducted at the University of the Pacific School of Dentistry found that BreathAssure Dental Gum reduced the accumulation of plaque on the test subjects' teeth by 35 percent. Volunteers chewed the gum three times a day for 20 minutes, while a control group chewed a placebo gum. All test subjects practiced regular brushing and flossing routines during the study. The results of this study were made public on February 2, 1999.

One drawback to chewing gum is the potential for TMJ (temporomandibular joint) problems. Gum chewing may result in muscle fatigue and pain--especially if it is done frequently and/or for long periods of time. In one survey of orthodontists and oral surgeons, 46 percent believed that infrequent gum chewing could lead to TMJ concerns. This statistic increased to 65 percent for frequent gum chewers. Orthodontists appeared to express more concern than oral surgeons. Perhaps they are also worried about the effects of gum chewing on orthodontic appliances. Research, however, has not really established the relationship between gum chewing and development of structural changes within the jaw joint, which could lead to fatigue and/or pain.

Gum chewing is an individual choice. It is a good idea to brush your teeth, or at least rinse your mouth with water after chewing gum. If you are susceptible to decay, gum containing Xylitol may have some benefit for you. If you experience muscle fatigue, jaw joint pain or headaches from chewing gum, perhaps infrequent chewing or excluding gum altogether may be the best solution.

Does this answer your question? *wink wink*