Xylitol Gum Research Articles

Xylitol and Dental Caries: an Overview For Clinicians

An overview of studies about xylitol and dental caries suggests potential clinical dental applications for xylitol. Xylitol is a naturally occurring, low-calorie sugar substitute with anticariogenic properties. Data from recent studies indicate that xylitol can reduce the occurrence of dental caries in young children, schoolchildren, and mothers, and in children via their mothers. Xylitol, a sugar alcohol, is derived mainly from birch and other hardwood trees. Short-term consumption of xylitol is associated with decreased Streptococcus mutans levels in saliva and plaque. Aside from decreasing dental caries, xylitol may also decrease the transmission of S. mutans from mothers to children. Commercial xylitol-containing products may be used to help control rampant decay in primary dentition. Studies of schoolchildren in Belize and Estonia, along with data from the University of Washington, indicate that xylitol gum, candy, ice pops, cookies, puddings, etc., in combination with other dental therapies, are associated with the arrest of carious lesions. A prospective trial in Finland has demonstrated that children of mothers treated with xylitol had lower levels of S. mutans than children of mothers treated with chlorhexidine or fluoride varnish. Food products containing xylitol are available commercially and through specialized manufacturers, and have the potential to be widely accessible to consumers.

Does chewing xylitol gum result in suppression of mutans streptococci?

Design Randomised controlled trail using a health-centre population in Finland.Intervention 195 pregnant women with high mutans streptococci counts were randomised into three groups, xylitol (X; n=127), chlorhexidine varnish (CHX; n=32) or fluoride varnish (F; n=36). In group X, mothers were recommended to chew xylitol gum two to three times per day, starting at 3 months from delivery and continuing until their child was 3 years of age. The CHX- and F-group mothers received chlorhexidine or fluoride varnish at 6, 12 and 18 months after the birth of the child. Children received routine dental care (oral hygiene instruction, dietary advice fluoride treatment and restorative treatment) where necessary. Standardised plaque and salivary sampling was undertaken.Outcome measure Mutans streptococcus levels in plaque and saliva.Results Loss to follow-up was 19% at 3 years and 25% at 6 years. The reported proportion of the children who were colonised by mutans streptococci are shown (see Table 1) with a calculated worst-case scenario analysis assuming the best possible outcomes for groups CHX and F and the worst for group X. Numbers-needed-to-treat are presented comparing groups X and F.Conclusions Chewing xylitol gum by mothers who have high mutans streptococcus counts results in long-term suppression of the bacterium in their offspring.

Xylitol gum chewing by mothers of infants may result in long-term lowering of mutans streptococci levels in their children

Xylitol gum chewing by mothers of infants may result in long-term lowering of mutans streptococci levels in their children

MAINTAINING MUTANS STREPTOCOCCI SUPPRESSION: WITH XYLITOL CHEWING GUM

One strategy for treating dental caries is to suppress oral mutans streptococci, or MS, with chlorhexidine, or CHX, mouthrinse. Oral MS levels, however, tend to quickly return to baseline values without further intervention. In this clinical study, the authors evaluated the effect of xylitol chewing gum on MS regrowth. The authors selected 151 subjects with elevated oral MS levels (> or = 105 colony-forming units per milliliter, or CFU/mL, of paraffin-stimulated saliva). Subjects rinsed with 0.12 percent CHX gluconate mouthrinse twice daily for 14 days. The authors then randomly assigned the subjects to one of three groups. Those in the test group (n = 51) chewed a commercial xylitol gum three times daily for a minimum of five minutes each time for three months. The placebo group subjects (n = 50) used a commercial sorbitol gum, and the control group subjects (n = 50) did not chew gum. The authors estimated MS load on the dentition using paraffin-stimulated saliva samples. The authors serially diluted the samples, plated them on selective media and incubated them anaerobically; they then enumerated the colonies under a stereomicroscope. MS levels were not significantly different between the three groups at baseline (mean log CFU/mL +/- standard deviation: 5.4 +/- 0.7, 5.4 +/- 0.8, 5.2 +/- 0.7, respectively) nor after CHX therapy (2.7 +/- 0.8, 3.1 +/- 1.1, 3.0 +/- 1.1, respectively). After three months of gum chewing, the test group subjects had significantly lower salivary MS levels (3.6 +/- 1.2) than did the placebo (4.7 +/- 1.2) or control (4.4 +/- 1.3) group subjects. Xylitol chewing gum appears to have the ability to prolong the effect of CHX therapy on oral MS. Maintaining long-term caries-pathogen suppression is feasible with currently available commercial products and can be expected to result in significant caries inhibition.

The optimum time to initiate habitual xylitol gum-chewing for obtaining long-term caries prevention.

Habitual xylitol gum-chewing may have a long-term preventive effect by reducing the caries risk for several years after the habitual chewing has ended. The goal of this report was (1) to determine if sorbitol and sorbitol/xylitol mixtures provide a long-term benefit, and (2) to determine which teeth benefit most from two-year habitual gum-chewing - those erupting before, during, or after habitual gum-chewing. Children, on average 6 years old, chewed gums sweetened with xylitol, sorbitol, or xylitol/sorbitol mixtures. There was a "no-gum" control group. Five years after the two-year program of habitual gum-chewing ended, 288 children were re-examined. Compared with the no-gum group, sorbitol gums had no significant long-term effect (relative risk [RR], 0.65; 95% confidence interval [c.i.], 0.39 to 1.07; p < 0.18). Xylitol gum and, to a lesser extent, xylitol/sorbitol gum had a long-term preventive effect. During the 5 years after habitual gum-chewing ended, xylitol gums reduced the caries risk 59% (RR, 0.41; 95% c.i., 0.23 to 0.75; p < 0.0034). Xylitol-sorbitol gums reduced the caries risk 44% (RR, 0.56; 95% c.i., 0.36 to 0.89; p < 0.02). The long-term caries risk reduction associated with xylitol strongly depended on when teeth erupted (p < 0.02). Teeth that erupted after 1 year of gum-chewing or after the two-year habitual gum use ended had long-term caries risk reductions of 93% (p < 0.0054) and 88% (p < 0.0004), respectively. Teeth that erupted before the gum-chewing started had no significant long-term prevention (p < 0.30). We concluded that for long-term caries-preventive effects to be maximized, habitual xylitol gum-chewing should be started at least one year before permanent teeth erupt.

A Descriptive Report of the Effects of a 16-Month Xylitol Chewing-Gum Programme Subsequent to a 40-Month Sucrose Gum Programme

A previous caries trial (Belize studies) involved the usage of sucrose chewing-gum for a period of 40 months in one group of initially 10-year-old subjects in an environment of high sugar consumption, high caries activity, and limited access to restorative care. After the termination of the 40-month supervised sucrose gum usage, the 109 subjects of the original sucrose group retrieved at the endpoint of the original trial were invited to participate in a xylitol chewing-gum programme (involving the usage of the ‘100% pellet-shaped formular’) for 16 months. The average daily consumption level of xylitol was up to 14 g per subject, normally used in seven daily chewing episodes. Although most subjects used chewing-gum at schools and received their gum portions from a school official, gum chewing during these 16 months was mostly unsupervised. After 16 months, 83 subjects (76%; mean age 14.9 years) were retrieved. The caries status of these subjects was examined by the same calibrated, blinded examiners as in the original trial. To mask the examiners, 141 similar non-participating subjects were recruited from the same school classes and were examined in a random order with the gum-using subjects, according to the same standard routine. The intensified xylitol gum usage for 16 months was associated with a reduction of the mean DMFS score from 10.9 (at 40 months) to 9.3 (at 56 months, p = 0.0013) and a reduction in caries rate from 20.1 caries onsets per 1,000 surface-years (40-month period average rate) to 10.2 caries onsets per 1,000 surface-years. The reduction in DMFS score resulted mostly from the change in the D component of the index and possibly reflected a stabilisation of the caries process and rehardening of some caries lesions to a non-progressive carious state.

Sugar substitutes, chewing gum and dental caries--a review.

The prevalent use of chewing gum has prompted interest in its dental effects. Important defining aspects are the ability to use sugar substitutes in gum manufacture and the prolonged stimulation of a protective flow of saliva. The main sugar substitutes used are sorbitol and xylitol. Because it is not fermented by oral bacteria, xylitol is considered to be non-cariogenic, and while sorbitol in solution can be fermented slowly by mutants streptococci, chewing sorbitol-sweetened gum does not cause a fall in plaque pH. Effects of chewing sugar-free gum on the ability of plaque to form acid from sucrose are equivocal, although the tendency is for the plaque acidogenicity to be reduced with the use of xylitol gum for 2-3 weeks, due to its inhibitory effects on mutants streptococci. Gum-chewing also stimulates a protective salivary flow when used after an acidogenic stimulus, and may enhance salivary function, especially in subjects with low flow rates. Sorbitol and xylitol gums have similar beneficial effects in promoting enamel remineralisation in short-term in-situ experiments. Clinical trials indicate that xylitol gum has a useful anticaries role, superior to the effects of sorbitol gum. In conclusion, both sorbitol and xylitol chewing gums are non-cariogenic in contrast to sugared gum, and exhibit beneficial anticaries properties through salivary stimulation. In addition, xylitol's antibacterial properties seem likely to lead to caries reductions superior to the more modest reductions with sorbitol gum.

ORAL HEALTH PROMOTION AND PREVENTION FOR OLDER ADULTS

An oral health promotion and prevention program customized to individual needs begins with a thorough assessment of function and risk profile for dental diseases. Toothbrushes and interproximal cleaners can be selected or adapted to meet special needs of older adults. Fluoride use based on caries risk is an important adjunct to any prevention program. Other preventive agents such as chlorhexidine rinses and xylitol gum supplement the program as risk factors increase or when health and disability limit the ability to effectively perform oral hygiene procedures. Oral cancer screening examination is advocated on a regular basis for all older persons.

Xylitol fermentation by human dental plaque.

The aim of the present study was to examine xylitol metabolism by dental plaque collected immediately after the use of xylitol gum. Plaque was collected from 12 individuals immediately before and after xylitol exposure. The effect on xylitol metabolism by dental plaque of a 3 d discontinuation of the xylitol exposure was also examined. Xylitol metabolism by the plaque suspensions was initiated by adding [14C]xylitol and analyzed by HPLC. The results showed increased xylitol metabolism after 11 wk of chewing xylitol-containing gum. The ability to metabolize xylitol was rapidly reduced after the discontinuation of the xylitol exposure. It is suggested that an induction of enzymes in one or more of the species of plaque bacteria may have caused this effect. Glucose metabolism, which also was studied in the plaque samples, was decreased after xylitol exposure, but increased again 3 d after cessation of the xylitol exposure. It is suggested that the reduced glycolysis was caused by accumulation of intracellular xylitol-5-phosphate in some plaque bacteria during the xylitol exposure.

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). 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 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.

Effect of polyol gums on dental plaque in orthodontic patients

Sixty 11- to 15-year-old children wearing fixed orthodontic appliances were given chewing gums containing polyol for daily use after meals and snacks, to study whether the chewing of gums that contained slowly fermentable polyols (xylitol and sorbitol) affects the amount of dental plaque and the number of mutans streptococci present in plaque and saliva. The 60 subjects were randomly divided into four groups, each of which was provided with a supply of 1.35 gm pellet-shaped gums for a period of 1 month, as follows: (1) xylitol; (2) sorbitol; (3) xylitol-sorbitol mixture I (3:2); and (4) xylitol-sorbitol mixture 11 (4:1). In each group, two pellets with a total initial gum mass of 2.7 gm (maximum polyol dose per day: 10.5 gm), were used six times a day. The fresh and dry weight of dental plaque, collected at baseline and 28 days later from incisors, canines, and premolars from the area between gingival margin and the bracket, reduced in all groups, but most significantly (by 43% to 47%) in children receiving xylitol gum. The plaque and saliva levels of mutans streptococci did not change in the sorbitol group, but was significantly (in most cases) reduced by 13% to 33% in groups that received gum containing xylitol. Provided that the quantity of dental plaque and the plaque and salivary levels of mutans streptococci can be regarded as risk factors in dental caries, these results suggest that regular use of polyol gum—and especially gum that contains xylitol as the predominant sweetener—can reduce the caries risk in young patients wearing fixed orthodontic appliances. (AM J ORTHOD DENTOFAC ORTHOP 1995;107:497-504.)

Effect of Xylitol and Sorbitol in Chewing-Gums on Mutans Streptococci, Plaque pH and Mineral Loss of Enamel

Seventeen subjects with more than 3 x 10(5) mutans streptococci per millilitre of saliva completed this randomised, cross-over study. Four different chewing-gums, containing: (1) 70% xylitol, (2) 35% xylitol + 35% sorbitol, (3) 17.5% xylitol + 52.5% sorbitol, and (4) 70% sorbitol, were tested. The participants used 12 pieces of each gum per day for 25 days. During the four experimental periods, they wore a removable palatinal plate containing two demineralised enamel samples, and brushed their teeth with a non-fluoridated toothpaste. The results showed that an increased concentration of xylitol in the gum resulted in a lower number of mutans streptococci in both saliva and dental plaque, although the decreases were only significant in the saliva samples (p < 0.01). The pH drop in plaque, measured in vivo after a 1-min mouthrinse with a 10% sorbitol solution, was least pronounced after the 70% xylitol gum and most pronounced after the 70% sorbitol gum period (p < 0.01). No significant differences were found after a mouthrinse with a 10% sucrose solution. All demineralised enamel samples lost mineral during the experimental periods. However, the lesion depth as well as the mineral loss values, assessed microradiographically, did not differ significantly between the four chewing-gums.

Cariologic aspects of xylitol and its use in chewing gum: a review.

Several studies indicate that xylitol is not metabolized to acids either in pure cultures of oral microorganisms in vitro or in dental plaque in vivo. Chronic consumption of xylitol-sweetened chewing gum resulted in reduction of dental plaque, suppression of mutans streptococci, and reduced adhesiveness of plaque. So far, four field studies with regimens including chewing gum and other xylitol-containing products and four clinical trials have been carried out. All of the latter studies showed that a daily intake of two to three pieces of xylitol gum resulted in a defined reduction of caries. There are indications that regular and prolonged use of xylitol chewing gum may have a caries-preventive effect.

Effect of Chewing Xylitol Chewing Gum on Salivary Flow Rate and the Acidogenic Potential of Dental Plaque

Ten adults participated in the study which consisted of four experimental periods each lasting 2 weeks, during each of which subjects were assigned to one of four gum-chewing regimens: no gum, sucrose gum, sorbitol gum and xylitol gum. At the start and end of each test period unstimulated and stimulated salivary flow rates were determined. At the end of each test period the acidogenic potential of 48-hour dental plaque was measured using a Beetrode pH microelectrode. No statistically significant (p < 0.05) effect on salivary flow rate was observed. The xylitol chewing gum regimen resulted in significantly higher plaque pH than no gum, sucrose gum and sorbitol gum at 2, 10, 20, 30 and 60 min following a 10% sucrose rinse. In addition, xylitol gum regimen exhibited a significantly higher minimum pH and smaller area of the curve below pH 6. The results suggest that the regular use of xylitol-sweetened gum may serve to reduce the acidogenic potential of dental plaque.

Long-Term Xylitol Consumption and Mutans Streptococci in Plaque and Saliva

The effect of 4 to 6 years of habitual use of xylitol gum (greater than or equal to 2 times per day) on the viable counts of mutans streptococci in both plaque and saliva was evaluated in a cross-sectional study of participants of the Ylivieska xylitol study (Finland, 1982-1984). Paraffin-stimulated saliva was collected first, whereafter the remaining plaque was collected from all available tooth surfaces and pooled. The habitual xylitol consumers (n = 15) had less plaque than the controls (n = 21). The total viable counts of mutans streptococci in the plaque collected from the habitual xylitol users were about 10% of those determined in controls (p less than 0.01). The salivary mutans streptococci levels were relatively high in both habitual xylitol consumers and controls, as determined using a plate count and with an adhesion-based assay; no significant differences were detected between these groups. Thus, habitual xylitol consumption appeared not to be associated with a reduction in the total numbers of mutans streptococci in saliva. The plaque and the mutans streptococci were, however, more loosely bound to the tooth surfaces of the habitual xylitol users. The results of the plate count and the adhesion-based assay for salivary mutans streptococci were in good agreement for both habitual xylitol consumers and the controls. This suggests that it was the accumulation of plaque rather than the adhesiveness of mutans streptococci that was affected by the habitual consumption of xylitol.

A 24-month Clinical Study of the Incidence and Progression of Dental Caries in Relation to Consumption of Chewing Gum Containing Xylitol in School Preventive Programs

The effect of chewing gum containing xylitol on the incidence and progression of dental caries was tested in a sample of 274 children, aged eight and nine years, of low socio-economic status and high caries rate. They were divided into two experimental groups (15% and 65% xylitol chewing gum distributed three times a day at school) and one control group (without chewing gum). The three groups were exposed to the same basic preventive program. Children who chewed gum had a significantly lower net progression of decay (progressions-reversals) over a 24-month period than did the controls. Results for the two groups chewing gum were similar. Chewing xylitol gum had a beneficial effect on the caries process for all types of tooth surfaces, and especially for bucco-lingual surfaces. The two experimental groups had a DMF(S) increment of 2.24 surfaces, compared with 6.06 surfaces for the control group. For this indicator, there was no difference between the two experimental groups. Results for the plaque index were in agreement with those of the DMF(S) increment and the net progression of decay.

Long-term effect of xylitol chewing gum on dental caries.

About 85% (n = 269) of the subjects who participated in the Ylivieska follow-up studies on the effect of xylitol chewing gum on dental caries during 1982-84 or 1982-85 were re-examined in 1987 for the analysis of possible long-term preventive effects. Further caries reduction was found 2 or 3 yr after the discontinuation of the use of xylitol. The effect was especially marked in girls; the reduction in caries increment in the post-use years was 60% for the 2-yr users, suggesting that more pronounced caries reduction was associated with the most regular use of xylitol. In teeth erupting during the first year of the use of xylitol gum the long-term preventive effect was greater than in other teeth. Several explanations are suggested: lasting effect of the microbiological changes in the mouth, bacterial colonization on newly erupted teeth by organisms other than S. mutans, and/or thorough maturation of the teeth under favorable physico-chemical circumstances. The results suggest that the value of xylitol in caries prevention depends on the timing of the treatment in relation to the development of the dentition.

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.

Clinical Results After 12 Months from a Study of the Incidence and Progression of Dental Caries in Relation to Consumption of Chewing-gum Containing Xylitol in School Preventive Programs

This study was designed to evaluate the effect of chewing-gum containing xylitol on the incidence and the progression of dental caries. A sample of 433 children, aged 8 and 9 years, of low socio-economic status and high caries rate, was divided into two experimental groups (15% or 65% xylitol chewing-gum distributed three times a day at school) and one control group (without chewing-gum). The three groups were exposed to the same basic preventive program. Children who chewed gum had a significantly smaller DMF(S) increment over a 12-month period than did the control group. The former had increments of 1.58 surfaces, compared with 3.28 for the latter. No statistically significant difference, however, was demonstrated between the two experimental groups. The net progression of decay (progressions-reversals) showed a significant difference between the two experimental groups and the control group. In addition, 65% xylitol chewing-gum produced better results than did that containing 15% xylitol, suggesting a dose-response relationship. Chewing xylitol gum had a beneficial effect on the caries process for all types of tooth surfaces, but chewing gum with a higher xylitol content had an additional positive effect on buccolingual surfaces. A questionnaire asking the participants about stomach pain indicated that there was no difference between the experimental and control groups. The feasibility of such a preventive measure has been demonstrated by the excellent level of participation of both children and teachers. This activity could easily be integrated into existing preventive public health programs.

The effect of chewing xylitol gum on the plaque and saliva levels of Streptococcus mutans

Eating foods containing sucrose between meals can be highly cariogenic. The use of sucrose substitutes that provide the hedonistic appeal of sucrose, yet are not fermented by the plaque flora to the low pHs that are associated with caries, is a reasonable approach to caries control. Xylitol, a sweet-tasting pentitol, has been reported to cause about an 80% reduction in caries increment when chewed in a gum. The present investigation was designed to determine whether the chewing of xylitol gums affected the salivary and plaque levels of S mutans and lactobacilli. The chewing of xylitol gums for four weeks caused a significant reduction in saliva levels and plaque proportions of S mutans compared with pretreatment values. The levels were also significantly reduced to values obtained by chewing either sorbitol or fructose sweetened gum. The chewing of various gums had no significant effect on the proportions of lactobacilli in the plaque. These findings suggested that the small amounts of xylitol used (about 5 gm) resulted in a suppression of S mutans.