Effects of chewing gums sweetened with sorbitol or a sorbitol/xylitol mixture on the remineralisation of human enamel lesions in situ

Delivery of Active Agents from Chewing Gum for Improved Remineralization

Most surrogate measures of caries were developed to test products containing fluoride, typically at relatively high and closely controlled oral concentrations. However, since the primary mechanism for the remineralization of early enamel caries lesions by chewing gum is through stimulation of saliva, delivering Ca and Pi to the demineralized enamel lesion, established methods may lack the sensitivity to detect the additional benefit of an active agent without the strong remineralizing potential of fluoride. Issues related to the release of active agents from the gum matrix, dilution in the saliva, and limited oral retention time, along with taste, safety, regulatory, and cost concerns, impose further limitations. This paper reviews the efficacy of some active agents used in chewing gum for improved remineralization and includes results from in situ testing of calcium-containing gums, including calcium lactate, tetracalcium phosphate/dicalcium phosphate anhydrous, calcium citrate/encapsulated phosphate, and a calcium lactate/sodium phosphate blend. Despite promising in vitro data from these agents, they did not provide consistently superior results from in situ testing. There is a need to develop better predictive in vitro models for chewing gum, as well as improved sensitivity of in situ models to discriminate relatively small amounts of remineralization against a background of high biological variability.

Sugar-free chewing gum and dental caries: a systematic review

Objective:

To appraise existing evidence for a therapeutic / anti-cariogenic effect of sugar-free chewing gum for patients.

Method:

9 English and 2 Portuguese databases were searched using English and Portuguese keywords. Relevant articles in English, German, Portuguese and Spanish were included for review. Trials were excluded on lack of randomisation, control group, blinding and baseline data, drop out rate >33%, no statistical adjustment of baseline differences and no assessment of clinically important outcomes. Reviews were excluded on lack of information, article selection criteria, search strategy followed, search keywords, searched databases or lack of study-by-study critique tables. In cases of multiple reports from the same study, the report covering the longest period was included. Two reviewers independently reviewed and assessed the quality of accepted articles.

Results:

Thirty-nine articles were included for review. Thirty were excluded and 9 accepted. Of the 9 accepted, 2 trials of reasonable and good evidence value did not demonstrate any anti-cariogenic effect of sugar-free chewing gum. However, 7 articles, with 1 of strong, and 6 of good evidence value, demonstrated anti-cariogenic effects of chewing Sorbitol, Xylitol or Sorbitol/Xylitol gum. This effect can be ascribed to saliva stimulation through the chewing process, particularly when gum is used immediately after meals; the lack of sucrose and the inability of bacteria to metabolize polyols into acids.

Conclusion:

The evidence suggests that sugar-free chewing gum has a caries-reducing effect. Further well-designed randomised trials are needed to confirm these findings.

Sugar alcohols, caries incidence, and remineralization of caries lesions: a literature review

Remineralization of minor enamel defects is a normal physiological process that is well known to clinicians and researchers in dentistry and oral biology. This process can be facilitated by various dietary and oral hygiene procedures and may also concern dentin caries lesions. Dental caries is reversible if detected and treated sufficiently early. Habitual use of xylitol, a sugar alcohol of the pentitol type, can be associated with significant reduction in caries incidence and with tooth remineralization. Other dietary polyols that can remarkably lower the incidence of caries include erythritol which is a tetritol-type alditol. Based on known molecular parameters of simple dietary alditols, it is conceivable to predict that their efficacy in caries prevention will follow the homologous series, that is, that the number of OH-groups present in the alditol molecule will determine the efficacy as follows: erythritol >/= xylitol > sorbitol. The possible difference between erythritol and xylitol must be confirmed in future clinical trials.

Sucrose substitutes and their role in caries prevention

Many non- or low-cariogenic sucrose substitutes are currently available and are found as ingredients of a variety of candy, chewing gum, and drinks. Recently the role of sugar alcohols in promoting remineralisation of enamel has attracted much attention. Thus, the dental profession needs to understand the general characteristics and features of sugar substitutes to provide advice on oral health to patients as well as the general public. There are two critical requirements for sucrose substitutes, namely, being nutritionally appropriate and not being detrimental to the overall general health of the individual. The use of a greater variety of confectionary containing sucrose substitutes and the development of new substitutes with high nutritional value are essential in the battle against caries. In this paper we review in detail the characteristics of sucrose substitutes currently in use, their role in caries prevention and promotion of oral health.

Field Trial on Caries Prevention with Xylitol Candies among Disabled School Students

BACKGROUND

In a 1999 survey high caries levels were found among physically disabled school students in Kuwait.

OBJECTIVES

A field study was planned to test the efficacy of xylitol candies in preventing caries among individuals in two special schools in Kuwait.

METHODS

Altogether 176 students were examined in 2002 and 145 (105 in xylitol group and 40 in the control group) after 18 months' intervention. The WHO criteria were used in recording caries according to surfaces (third molars were excluded) by 2 calibrated examiners (E.H., M.S.). The students were allocated to the xylitol group only if the parent/caregiver returned the informed consent form. School health nurses distributed xylitol candies to the students 3 times during the school day (after breakfast and lunch, and before leaving the school).

RESULTS

In the xylitol group, the baseline DS and DMFS scores were 3.4 and 8.2 and in the follow-up 1.9 and 7.1, respectively. In the control group, the baseline scores were DS 3.9 and DMFS 9.8, and the follow-up scores DS 3.9 and DMFS 13.2.

CONCLUSION

Xylitol seemed to have a strong preventive and a clear remineralizing effect on caries.

Quantitative light-induced fluorescence: a potential tool for general dental assessment

Current dental diagnostic methods can detect caries but cannot quantify the mineral status of a lesion. Quantitative light-induced fluorescence (QLF) measures the percentage of fluorescence change of demineralized enamel with respect to surrounding sound enamel, and relates it directly to the amount of mineral lost during demineralization. Development of caries-like lesions and subsequent remineralization of the lesions were monitored by QLF. The results showed that the percentage of fluorescence change (Delta Q) increased linearly with the demineralization time and decreased with increased remineralization time. Stained teeth were whitened with a bleaching agent and the change in stain intensity (Delta E) was quantified using QLF. The results showed that Delta E decreased linearly as the tooth regained its natural color. Factors that might affect the use of QLF to detect and quantify caries were also examined. It was concluded that QLF could be used to detect and longitudinally monitor the progression or remineralization of incipient caries, however lesion detection may be limited by the presence of saliva or plaque and enhanced by staining. The change in shade of discolored teeth by whitening agents could be quantitatively measured by QLF.

[Effect of sucrose-containing gum and fluoridated dentifrice on in situ remineralization of artificial caries]

The aim of this study was to evaluate the remineralization of incipient carious lesions in bovine enamel in situ. Artificial carious lesions were produced and fixed in removable lower appliances in the region of the lingual surfaces of first molars, in six volunteers with ages between 18 and 22 years, who were subjected to 3 distinct experimental periods of 1 week each. In the first period (control group), patients brushed their teeth with a non-fluoridated dentifrice 4 times a day (after meals), and, in the second period (group I), patients used a dentifrice containing 1,500 ppm of fluorine (in the form of MFP). In the third period (group II) volunteers brushed their teeth with non-fluoridated dentifrice and used chewing gum containing 60% of sucrose during 20 minutes, 4 times a day (after meals). Before and after each treatment, the specimens underwent Vicker's hardness test (200 g of load), and the remineralization percentage (alpha) was calculated. The control group showed 2.78% of demineralization, and groups I and II showed 3.36 and 5.21% of remineralization, respectively. Statistical analysis (with Kruskal-Wallis and Miller's tests) showed significant difference (p < 0.05) between the control and experimental groups (I and II). Group II showed greater alpha than group I, but this difference was not significant. These results suggest that the use of sucrose-containing chewing gum and fluoridated dentifrice has a considerable effect on the remineralization of incipient carious lesions and may be a valuable alternative for their prevention.

The effect of chewing sugar-free gum on plaque regrowth at smooth and occlusal surfaces

BACKGROUND AND AIM

Chewing gum has the potential to provide oral health benefits including plaque control. The aim of this study was to determine the effects of chewing sugar free gum on plaque regrowth at buccal, lingual and occlusal surfaces of teeth.

METHOD AND MATERIALS

11 healthy and dentally-fit dental hygiene students participated in this randomised, single-blind crossover 4-day plaque regrowth study. From a zero plaque score on day 1, subjects suspended oral hygiene measures and either chewed gum or did not chew gum over 4 days. Gum chewing was one piece chewed for 30 min 4 x per day. On day 4, subjects were scored for plaque after disclosing from buccal, lingual and unrestored occlusal surfaces.

RESULTS

There was no significant difference in smooth surface plaque scores between the treatments but significantly less plaque accumulated (44%) at occlusal surfaces during gum chewing compared to no gum chewing.

CONCLUSION

Chewing gum can reduce plaque accumulation at sites of predilection for caries but has little or no effect at sites of predilection for gingivitis.

Saliva in health and disease: an appraisal and update

Saliva plays an important role in oral health monitoring, regulating and maintaining the integrity of the oral hard tissues and some soft tissues. This paper reviews the role of saliva, the prevalence of oral dryness and the consequent importance of salivary flow as well as the relationship between xerostomia and salivary gland hypofunction amongst the causes of oral dryness. Other aspects of oral conditions associated with saliva are also reviewed including Sjögren's Syndrome and oesophageal function. Finally, knowledge, and the current use of salivary tests and the utilisation of saliva as a diagnostic fluid are surveyed.

Chewing gum--facts and fiction: a review of gum-chewing and oral health

The world market for chewing gum is estimated to be 560,000 tons per year, representing approximately US $5 billion. Some 374 billion pieces of chewing gum are sold worldwide every year, representing 187 billion hours of gum-chewing if each piece of gum is chewed for 30 minutes. Chewing gum can thus be expected to have an influence on oral health. The labeling of sugar-substituted chewing gum as "safe for teeth" or "tooth-friendly" has been proven beneficial to the informed consumer. Such claims are allowed for products having been shown in vivo not to depress plaque pH below 5.7, neither during nor for 30 minutes after the consumption. However, various chewing gum manufacturers have recently begun to make distinct health promotion claims, suggesting, e.g., reparative action or substitution for mechanical hygiene. The aim of this critical review--covering the effects of the physical properties of chewing gum and those of different ingredients both of conventional and of functional chewing gum--is to provide a set of guidelines for the interpretation of such claims and to assist oral health care professionals in counseling patients.

Xylitol in caries prevention: what is the evidence for clinical efficacy?

Xylitol has attracted much attention as an alternative sweetener. Essentially all clinical studies concerning the effect of xylitol on caries development consent to its non-cariogenicity and to the beneficial effect of substituting sucrose with xylitol in chewing gums and sweets. However, claims of anti-caries or therapeutic effects, and superiority of xylitol over other polyols are still to be confirmed by well designed and conducted studies from independent research groups.

In situ de- and remineralisation of enamel in response to sucrose chewing gum with fluoride or non-fluoride dentifrices

OBJECTIVES

Enhancement of the remineralisation of artificial enamel lesions has been observed in an intraoral model whether subjects chewed gum sweetened with a non-cariogenic sweetener such as sorbitol [1-3] or sucrose [4] after meals or snacks, and with use of a conventional (1500 ppm F) fluoride dentifrice. Since most of the clinical surveys which have shown the potential cariogenicity of sucrose chewing gum [5] were conducted before use of fluoridated dentifrices became widespread, the effect of fluoride dentifrice on de- and remineralisation of artificial lesions in enamel in response to chewing sucrose-sweetened gum has been examined with the aim of attempting to resolve this apparent discrepancy.

METHODS

Subjects wore an intraoral device bearing an enamel lesion and chewed one piece of sucrose gum for 20 min after each of three meals and two snacks daily for two 3-week periods, during which they used a dentifrice containing either 0 or 1500 ppm F in a double-blind, cross-over design. Measurement of the mineral content of the lesions was determined by microradiography or polarised light microscopy.

RESULTS

It was found that remineralisation tended to occur with 1500 ppm F dentifrice, but demineralisation with non-F dentifrice; the difference in enamel mineral content between the two periods was significant (P < 0.05).

CONCLUSIONS

The results indicate that the potential cariogenicity of sucrose-containing chewing gum may indeed be negated by the use of a conventional fluoride dentifrice.

The influence of xylitol and fluoride on dental erosion in vitro

The aim was to determine the effect of xylitol, fluoride and xylitol/fluoride combined on the erosion of dental enamel by pure orange juice in vitro. Freshly extracted bovine incisors were sectioned vertically into four equal portions. Each portion was then coated with an acid-resistant nail varnish except for an enamel window on the labial surface of the tooth. These were then divided into four groups with each group containing one portion of each tooth selected randomly. Four erosive agents were prepared as follows: (A) pure orange juice only; pure orange juice plus either (B) xylitol (25% w/v) or (C) fluoride (0.5 parts/10(6)) or D) xylitol/fluoride (25% and 0.5 parts/10(6) respectively). Each group was assigned to one of the erosive agents and immersed six times daily for a period of 5 min on each occasion and stored in artificial saliva between exposures and for 12 hr overnight, for 24 days making a total of 12 hr of exposure to the assigned erosive agent. Sections were cut from each enamel specimen ground to a thickness of 80 microns and microradiographed. Mineral loss was quantified by a two-step image analysis. Mineral loss was significantly lower (p < 0.05) in group D (xylitol/fluoride) only when compared with group A (pure orange juice only). The numerical values of mineral loss could be ranked as follows: group D < group C < group B < group A. It was concluded that xylitol and fluoride have an additive effect in the reduction of dental erosion by pure orange juice in vitro.

The application of in situ models for evaluation of new fluoride-containing systems

Many in situ models have assessed the anticaries potential of fluoride-containing systems (Stookey et al., 1985; Mellberg et al., 1986, 1992a,b; Corpron et al., 1986; Featherstone and Zero, 1992; Ogaard and Rolla, 1992; Stephen et al., 1992). Several models have reportedly been validated according to guidelines proposed by Proskin et all. (1992). The proposed guidelines cover only dentifrices containing sodium fluoride (NaF) or sodium monofluorophosphate (SMFP) as active ingredients. These compounds are the most widely used sources of fluoride in dentifrices, and dose-response clinical standards are available for both. Other fluoride compounds, such as amine fluoride (AmF) and stannous fluoride (SnF2), have also been proven effective in reducing caries (Muehler et al., 1957, 1958; Marthaler, 1968; Lu et al., 1980; Cahen et al., 1982). Profile standards for these fluorides were not included in the proposed guidelines, primarily due to the lack of clinical data necessary to establish a dose response for these ingredients. Criteria for demonstrating the efficacy of these ingredients, along with methods to assess new fluoride compounds, need to be established. In situ models are used to evaluate the anticaries potential of new compounds added to mouthrinses, gums, slow-release devices, etc. (Creanor et al., 1992; Manning and Edgar, 1992; Lamb et al., 1993; Toumba and Curzon, 1993; Wang et al., 1993). Ingredients are often added to dentifrices previously proven effective against caries in order to provide additional benefits of gum health, tartar control, cleaning, etc. Proposals are made regarding the in situ testing of new dentifrices containing clinically proven fluoride compounds other than NaF and SMFP, as well as alternative delivery systems, in order to assist in their evaluation.

Effects of fluoride-supplemented sucrose on experimental dental caries and dental plaque pH

Sucrose, 5% and 10% (w/v), supplemented with between 0 and 5 ppm fluoride (F), was tested for its influence in vitro on plaque-induced experimental in vitro enamel caries and plaque pH. Plaque growth on bovine enamel was initiated from saliva inocula and sustained in a multiple plaque growth system for up to 31 days by means of a basal medium with periodic applications of sucrose or sucrose supplemented with F. Change in enamel mineralization was assessed, before and after plaque growth, by microhardness testing and microradiography; pH was monitored with microelectrodes. It was found that enamel demineralization was inversely related to the F concentration in the range 2 to 5 ppm, for both 5% and 10% sucrose. Plaque pH responses were unaffected by the F supplements.

Saliva stimulation and caries prevention

The protective role of saliva is demonstrated by the rampant caries seen in human subjects with marked salivary hypofunction, and in desalivated animals. In normal cases, however, the relationship between saliva flow and coronal or root caries experience is doubtful, and to examine the concept that stimulation of saliva might have protective effects against caries, one must look beyond a simple correlation between caries and flow rate. Protective properties of saliva which increase on stimulation include salivary clearance, buffering power, and degree of saturation with respect to tooth mineral. These benefits are maximized when saliva is stimulated after the consumption of fermentable carbohydrates, by reducing the fall in plaque pH leading to demineralization and by increasing the potential for remineralization. Plaque acid production is neutralized, and experimental lesions in enamel are remineralized, when gum is chewed to stimulate saliva after a carbohydrate intake. The pH-raising effects are more easily explained by the buffering action of the stimulated saliva than by clearance of carbohydrates. The remineralization action depends upon the presence of fluoride. These findings suggest that the protective actions of saliva can be mobilized by appropriate salivary stimulation, and that in addition to established procedures such as tooth cleaning and fluoride regimens, eating patterns which lead to saliva stimulation to increase the potential for saliva protection might be included in recommendations for caries prevention. Confirmation of this concept in clinical tests is required.

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.

An in vitro stimulation of the effects of chewing sugar-free and sugar-containing chewing gums on pH changes in dental plaque

The objective of these studies was to simulate the effect of chewing sugar-free and sucrose-containing chewing gums on the return of the pH to neutrality after exposure to sucrose of plaque located on the buccal (BLM) and lingual (LLM) surfaces of the lower molar teeth. In study 1, a 0.5-mm-deep artificial plaque containing Streptococcus oralis cells was exposed to 10% sucrose for one min, and a 0.1-mm-thick film of sucrose-free artificial saliva was then flowed over the plaque surface at the unstimulated salivary film velocities previously found at the BLM and LLM sites. At the time of the pH minimum (pH 4-5), one of three conditions was simulated: (a) a no-gum-chewing control, or chewing for 20 min on either (b) a sugar-free gum or (c) a sucrose-containing gum. The recovery of the plaque pH to resting values was rapid during simulation of chewing a sugar-free gum (SFG), much slower with the no-gum control, and even slower with simulation of chewing a sucrose-containing gum (SCG). The pH recovery was slower with the BLM than the LLM plaque. In study 2, the BLM plaque was exposed to a 2% sucrose solution for 20 min under stimulated salivary conditions, to simulate the consumption of a meal, followed by one of conditions (a), (b), or (c) described above. The pH recovery with simulation of chewing a SCG was faster than with the no-gum control, but much slower than with the SFG simulation.(ABSTRACT TRUNCATED AT 250 WORDS)