Kauko K. Mäkinen

Xylitol Chewing Gums and Caries Rates: A 40-month Cohort Study

Dental caries is a pandemic infectious disease which can affect the quality of life and consumes considerable health care resources. The chewing of xylitol, sorbitol, and even sugar gum has been suggested to reduce caries rates. No clinical study has simultaneously investigated the effectiveness of these gums when compared with a group receiving no chewing gum. A 40-month double-blind cohort study on the relationship between the use of chewing gum and dental caries was performed in 1989-1993 in Belize, Central America. One thousand two hundred and seventy-seven subjects (mean age, 10.2 years) were assigned to nine treatment groups: one control group (no supervised gum use), four xylitol groups (range of supervised xylitol consumption: 4.3 to 9.0 g/day), two xylitol-sorbitol groups (range of supervised consumption of total polyols: 8.0 to 9.7 g/day), one sorbitol group (supervised consumption: 9.0 g/day), and one sucrose group (9.0 g/day). The gum use during school hours was supervised. Four calibrated dentists performed the caries registrations by means of a modified WHO procedure. The primary endpoint was the development of an unequivocal caries lesion on a non-cavitated tooth surface. Compared with the no-gum group, sucrose gum usage resulted in a marginal increase in the caries rate (relative risk, 1.20; 95% confidence interval, 0.96 to 1.49; p = 0.1128). Sorbitol gum significantly reduced caries rates (relative risk, 0.74; 95% confidence interval, 0.6 to 0.92; p = 0.0074). The four xylitol gums were most effective in reducing caries rates, the most effective agent being a 100% xylitol pellet gum (relative risk, 0.27; 95% confidence interval, 0.20 to 0.36; p = 0.0001). This gum was superior to any other gum (p < 0.01). The xylitol-sorbitol mixtures were less effective than xylitol, but they still reduced caries rates significantly compared with the no-gum group. DMFS analyses were consistent with these conclusions. The results suggest that systematic usage of polyol-based chewing gums reduces caries rates in young subjects, with xylitol gums being more effective than sorbitol gums.

Turku sugar studies V: Final report on the effect of sucrose, fructose and xylitol diets on the caries incidence in man

The purpose was to study differences in the caries increment rate as influenced by various sugars. The trial involved almost complete substitution of sucrose (S) by fructose (F) or xylitol (X) during a period of 2 years. There were no significant initial differences as to caries status between the prospective sugar groups; 35 subjects in the S-group, 38 in the F-group, and 52 in the X-group. During the entire study 10 subjects discontinued or were excluded. The clinical and radiographical observer error was reported and discussed. After 2 years the mean increment of decayed, missed and filled tooth surfaces was 7.2 in the S-group, 3.8 in the F-group, and 0.0 in the X-group. The weakness of the DMFS-index in not showing the development of new secondary caries and the increase in size of the lesions was overcome by expressing the caries activity in terms of indices showing the total quantitative and qualitative development. The results showed a massive reduction of the caries increment in relation to xylitol consumption. Fructose was found to be less cariogenic than sucrose. It was suggested that the non- and anticariogenic properties of xylitol principally depend on its lack of suitability for microbial metabolism and physico-chemical effects in plaque and saliva.

Turku sugar studies XVIII: Incidence of dental caries in relation to 1-year consumption of xylitol chewing gum

A longitudinal study was carried out in order to evaluate the caries incidence as affected by partial substitution of dietary sucrose (S) with xylitol (X), the effects of S- or X-containing chewing gums being compared during one year. The material comprised initially 102 young adults, predominantly dental and medical students, divided randomly into S- and X-groups. During the study 2 subjects were excluded, one due to lack of cooperation, the other not being allowed to enter the assigned S-group due to excessive caries prevalence. The subjects consumed 4.0 chewing gums per day in the S-group and 4.5 in the X-group. The frequency of sucrose intake was 4.2 times per day in the S-group, and 4.9 in the X-group. The caries incidence, assessed independently by clinical and radiographical means, expressed as the mean increment of decayed, missed and filled tooth surfaces, was 2.92 in the S-group, and --1.04 in the X-group. The corresponding values, when considering additionally the secondary caries reverals, were 3.76 in the S-group, and 0.33 in the X-group. The caries incidence was also expressed in combined quantitative and qualitative terms by considering in addition to the above parameters, also the changes in lesion size. The caries activity index thus calculated was 4.96 in the S-group, and 0.88 in the X-group. The results show a profound difference in the caries increment rate between the two experimental groups. The findings clearly indicate a therapeutic, caries inhibitory effect of xylitol.

Xylitol chewing gum in caries prevention: a field study in children

As the prevalence of dental caries decreases in industrialized nations like the United States, it simultaneously increases in developing nations and Third World countries. The decrease in the West is attributed to increased use of fluorides, but the increase in developing countries has been explained by an increase in the consumption of sugar. As this information continues to propel researchers to find sucrose substitutes, xylitol has been singled out as a proposed sucrose replacement. The question tackled by this study was: Can the daily use of chewing gum containing xylitol increase the efficacy of the existing caries-preventive measures now regularly used for 11- to 15-year-old children in most industrialized western countries?

Effect of Sorbitol, Xylitol, and Xylitol/Sorbitol Chewing Gums on Dental Plaque

The effect of sorbitol (SOR), xylitol (XYL), and the mixture XYL/SOR in chewing gums on dental plaque was studied in three groups of 7 adults (mean age 22.5 years). A fourth group of habitual users of sucrose-containing gums was used as a control. The study involved a 2-week, no-gum period followed by the use of the polyol gums for 2 weeks (10 gums/day in 5 2-gum doses). The daily consumption of XYL and SOR in the XYL and SOR groups was 10.9 g, whereas in the XYL/SOR group, 8.5 and 2.4 g of these polyols were used per day. At the end of the gum period the acidogenic response of the 48-hour plaque was tested using a 10-ml mouthrinse containing the polyols (10% w/v) present in the experimental gums, followed by a 10-ml rinse of 10% (w/v) sucrose solution. The plaque of the subjects who used XYL and XYL/SOR gums showed a significantly better ability to resist pH drops induced by the sucrose rinse than the plaque in the SOR gum group. No changes in resting pH values were observed in the XYL and XYL/SOR groups, whereas the use of SOR gum was associated with significantly lower pH values. The amount of plaque decreased in the XYL/SOR (24.3%) and the XYL (29.4%) groups, but increased in the SOR (48.3%) group, the changes in the SOR group differing significantly from those found in the other groups. The plaque and saliva levels of Streptococcus mutans generally increased in the SOR group, but decreased in groups which used XYL.

The Rocky Road of Xylitol to its Clinical Application

Theresults ofthe Turku studies were soonrecognized, firstin the then-SovietUnion, wherexylitol hadbeenroutinely usedin the diets ofdiabetic subjects. Atwo-year study conducted inthe state ofKazakhstan demonstrated a >70%reduction in theoverall caries incidence in the xylitol group compared with thesucrose group. The next trials were those conducted under theauspices ofthe WorldHealth Organization. TwoWHOstudieswere successfully completed: one in French Polynesia (1981-84), andanotherin Hungary, intheearly 1980s. Theformertrialinvolved a 32-month

Concentration of Thiocyanate and Ionizable Iodine in Saliva of Smokers and Nonsmokers

A total of 27 smokers and 92 nonsmokers were analyzed for salivary thiocyanate and ionizable iodine concentrations. Smoking statistically increased the amount of thiocyanate and decreased that of iodine in the saliva samples significantly. Male smokers. had significantly more thiocyanate and less ionizable iodine in saliva than female smokers.

Solubility of calcium salts, enamel, and hydroxyapatite in aqueous solutions of simple carbohydrates

SummaryThe solubility of various Ca(II) salts, hydroxyapatite, and powdered human dental enamel in the presence of simple carbohydrates was studied by determining the complex strength between Ca(II) and the carbohydrates. In 1.0m CaSO4, the following simplified sequence of complex strengths was obtained for the more common carbohydrates: Na-citrate>d-sorbitol>xylitol>d-mannitol>d-fructose>d-glucose>d-xylose. Whereas the more soluble Ca(II) compounds (like CaSO4) exerted measurable complexation with xylitol, no such complexation was found with hydroxyapatite and enamel powder. This also concerned other alditols. Calculation of the stability constants (K) showed sorbitol (K=0.81 M) and xylitol (K=0.67m) to form stronger complexes in saturated CaSO4 than other alditols. The most suitable coordination site appeared to be a vicinalcis-cis-triol. Precipitation studies showed that 0.5m xylitol and 0.5 M sorbitol significantly retarded the formation of calcium phosphate precipitates from a solution of Ca(II) and phosphate, compared with the effect caused by glucose, sorbose, or xylose. The effect caused by xylitol and sorbitol was explained in terms of partial displacement of water molecules in the primary hydration layer of Ca(II) ions, caused by competition between polyol and water molecules. In the presence of aldoses and ketoses, virtually instantaneous precipitation occurred. These results suggest that open-chain alditols may influence the chemical reactions of Ca(II) in plaque, saliva, and caries lesions. Alditols do not function as demineralizing agents of the teeth, however. Through the retarding effect on calcium phosphate precipitation, alditols may favorably govern remineralization of carious lesions.

Long-Term Effect of Xylitol Chewing Gum in the Prevention of Dental Caries: A Follow-Up 5 Years after Termination of a Prevention Program

About 65% of the original 258 children who participated in 1982-1984 in a caries prevention program involving the use of xylitol chewing gum were retrieved in 1989 for a follow-up study. Ninety-five subjects from the original xylitol (X) group and 70 subjects from the original control (no-gum, C) group were available. In 1984, when the children completed the program at the age of 13-14 years, the caries scores were significantly lower in children who had used xylitol gums daily, compared with the C group. In 1989, 5 years after the discontinuation of the gum program, the difference between the X and C groups had continued to increase in favor of the X group. These effects were explained by assuming that the X gum program had facilitated the establishment of a low-virulent bacterial flora on the surfaces of the teeth, and especially on those teeth that erupted during the trial proper. This type of results are possibly helpful when evaluating cost-benefit ratios of caries prevention.

Oral Biochemical Status and Depression of Streptococcus mutans in Children during 24- to 36-Month Use of Xylitol Chewing Gum

Plaque and whole saliva samples were collected from initially 11- to 12-year-old children randomly chosen from two groups which participated in a 2- to 3-year field trial designed to test the efficacy of xylitol chewing gums in caries prevention. No initial differences were observed between the groups with regard to the plaque levels of Streptococcus mutans, but at the end of the 2-year xylitol gum regimen, the levels were smaller (p less than 0.05) in children using xylitol gum than in control children. In a similar follow-up study on children who were considered to be at high risk with regard to dental caries and who continued the study over a 3rd year, the xylitol-consuming subjects showed at the end of the study significantly smaller (p less than 0.004) salivary S. mutans counts than the control children. These effects were achieved after using up to 3 xylitol gums/day (daily xylitol dose per child was 7-10 g). Salivary flow rate and several salivary chemical parameters did not change.