XYLITOL, which sweetens some chewing gums, can kill certain bacteria found in saliva which contribute to tooth decay. The merits of chewing gum in relation to preventing tooth decay are well publicised. Literature and TV advertisements refer to the buffer effects that saliva has on dental plaque, and everyone knows that chewing gum provokes salivary flow. However, there is a new mechanism by which chewing gum helps prevent caries.
That aspect is related to the actual composition of the chewing gum. Several studies of humans have examined the effects of partial or total substitution of sugar by xylitol in chewing gum. Xylitol is a sugar alcohol found in plants. It tastes sweet but is not fermentable sugar. Although it is chemically classified as an alcohol, it does not behave as such.
Tooth decay is an infectious disease significantly influenced by diet and the pattern of its consumption by the host. Its dependency on the ingestion of fermentable dietary carbohydrate (sugar) is beyond question. However, tooth decay does not occur in germ-free animals, regardless of their diet, thus establishing it as a fundamental microbiological disease. Based on these facts, researchers are working consistently to identify new ways to combat tooth decay.
For centuries, it has been known that salivation contributes positively to oral hygiene by literally washing away the colonies of caries-producing germs that constantly proliferate on the tooth’s surface. The practice of chewing gum originated with the act of keeping a smooth pebble in the mouth. Bad breath may be resisted in this way.
As part of the famous Turku Sugar Studies, a comparison of caries experience was made among three groups of adults whose diets consisted of foods with fructose substituted for sucrose, xylitol substituted for sucrose, or the usual sucrose-containing foods, which were consumed exclusively. The results, after two years, supported by a variety of microbiological, salivary, and other observations, demonstrated a dramatic reduction in decay incidence—about 85 per cent compared to the ordinary sugar diet.
Studies clearly demonstrate the non-carcinogenicity of high xylitol (65 per cent) content gum. They also suggested that such chewing gum was a caries inhibitor, despite the limited time, quantity, and exposure of the dentition to the gum. Of course, it should be recognised that chewing gum would seem to be an ideal vehicle for delivering caries-inhibitory substances at relatively high concentrations to the surfaces of the teeth, although the quantities ingested may be minimal.
The factors which are conducive to tooth decay are remarkably localised to the surfaces of the teeth. They are plaque, its bacterial population, the acid produced from sugar in the plaque in juxtaposition to the tooth surface, and the sugar challenges the plaque flora.
Finally, certain factors should be involved with chewing gum for the sake of oral hygiene. The chewing gum must contain xylitol sweetener instead of sugar. The content of xylitol should be high, that is, over 60 percent, because it is the xylitol that specifically attacks the germ (Strep mutans), which causes tooth decay. The gum should be chewed for at least 20 minutes a day in total. This implies that one may chew the gum four times for five minutes throughout the day to achieve the maximum effect.
By the way, xylitol is lethal in dogs—keep your chewing gum away from them.