Cariogenicity refers to the susceptibility of tooth decay which is an infectious disease powerfully affected by the diet and by the pattern of its consumption by the host. Its dependency on fermentable dietary carbohydrate (sugar) ingestion is beyond question. However, caries does not occur in germ-free animals, no matter 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.

The merits of chewing gum as it relates to preventing tooth decay is 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. But there is a new mechanism, whereby chewing gum helps prevent caries. That aspect has to do with 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 sweet, but is not a fermentable sugar. Actually, it is chemically classified as alcohol.

As part of the famous Turku Sugar Studies, a comparison of caries experience was made among three groups of adults whose diets contained diverse foods in which fructose-substituted-for sucrose, xylitol-substituted-for sucrose, or the usual sucrose-containing foods were exclusively consumed. The results after two years, supported by a variety of microbiological, salivary and other observations, demonstrated a dramatic reduction of decay incidence, about 85 percent by comparison with the ordinary sugar diet.

Studies clearly demonstrate the non-cariogenicity of high xylitol ( 65 percent) content gum. They also suggested that such chewing gums was a caries inhibitor, despite the limited time and 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 very small.

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 challenge to 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 which specifically attacks the germ (strep mutans), which causes tooth decay. The gum should be chewed for at least a total of 20 minutes a day. This implies that one may chew the gum four times for five minutes during the entire day, so as to derive the maximum effect. Now, even tooth whitening gum is sold on the local market.