By Deborah Gilbert
News and Information Services
Chewing gum with xylitol—a natural, “sugarless” sweetener—not only dramatically reduces new cavities—it helps to reverse the process of decay in already active cavities, according to a U-M study of more than 1,200 children.
The gum must be chewed for at least five minutes, three to five times a day, to be effective.
Kauko K. Makinen, professor of dentistry and biochemistry, reported his findings earlier this month at the International Association for Dental Research meeting in Chicago.
“When bacteria in the mouth metabolize sucrose, the standard gum and candy sweetener, they break it down eventually into acid compounds that create cavities in most individuals,” Makinen said. The same process may occur with sorbitol, a sweetener commonly used in sucrose-free gums, although the amount of acid produced is much smaller.
“However, oral bacteria do not metabolize xylitol efficiently, so almost no acid is produced,” the U-M researcher explained. “Also, regular chewing with xylitol gum stimulates the production of saliva—nature’s own mouthwash, which also reduces cavities.”
Makinen began his 40-month study of 1,227 children in September 1989 in Belize, Central America. The children, who were 9–11 years of age, attended 19 public schools in Belize City where their teachers supervised the use of the gum three to five times a day.
The gums in the study were sweetened with either sucrose, sorbitol or xylitol, or a mix of the various sweeteners. One group of children received no gum through the program.
Before the gum program began, dentists examined the children and counted the cavities on each surface of each tooth, as well as the missing and filled teeth, creating a DMFT (decayed/missing/filled teeth) score for each child. The dentists examined the children and calculated the score again at 16, 28 and 40 months.
“Before the children began chewing the gum, the mean DMFT score was about 5.5. At the 28-month exam, however, the mean score in the group of children who had chewed gum sweetened exclusively with xylitol dropped to about 4.0.
“Not only had most children in the xylitol-only group developed no new cavities, they actually had re-mineralized some old ones, so they were no longer decaying,” Makinen said.
“Cavities will re-mineralize naturally if people reduce the frequency of eating sugar and significantly improve their oral hygiene. The cavity does not fill up, but the surface of the cavity hardens over and seals itself, so it decays no further.”
Children who chewed the sorbitol gum had a mean DMFT score of 6.5 at the 28-month exam while the children who chewed sucrose gum had a mean score of about 8.0. The children who chewed no gum as part of the program had a score of about 7.5.
The 40-month dental examinations are currently under way, “and we expect to find similarly positive results,” Makinen said.
In 1990, Makinen launched a second, two-year study of 550 6-year-olds attending schools in Dangriga, Belize, or in nearby villages. “The 24-month results among the younger children appeared to be similar, with the exception that the re-mineralization process in the baby teeth seemed to occur even faster than it did in the permanent teeth of the older children in the first study,” Makinen said.
Xylitol has the same number of calories as sugar and is found in minute amounts in fruits and vegetables. It also is produced in the human body during the metabolic process.
Made from birch tree chips in Europe and corn stalks in the United States, xylitol was approved as a dietary sweetener by the U.S. Food and Drug Administration in 1963. It is widely used in chewing gums in Europe and Canada, and is used worldwide as a sweetener for diabetics. Some American gum manufacturers also use small amounts of xylitol in some chewing gums, but the smaller amounts have not been tested yet in long-term clinical trials.
Makinen’s study in Belize was funded by the Leaf Group, an American subsidiary of Huhtamaki, a candy and pharmaceutical manufacturer in Finland.
