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

Effects of xylitol-containing chewing gum on the oral microbiota

In this interventional study, a randomized controlled trial was used to evaluate the short-term effects of xylitol-containing chewing gum on the salivary microbiota. In total, 70 healthy adult men recruited from the Japan Ground Self Defense Force participated in the study during a 2-day training at Yamaguchi camp, Yamaguchi Prefecture, Japan. The men were randomly divided into two groups: one group chewed two pieces of xylitol-containing chewing gum 7 times/day for 2 days (n = 34) and the other did not (n = 36). Baseline and follow-up stimulated saliva samples were collected and the salivary microbial composition was assessed using the 16S rRNA gene next-generation sequencing analysis. The total salivary bacterial count was quantified using a quantitative real-time PCR system. No statistically significant difference was found between the two groups regarding any parameter analyzed in the baseline samples; however, the follow-up samples of the test group showed significantly lower total salivary bacterial count than those of the control group. Conversely, no significant difference was observed in the overall composition of the salivary microbiota between the baseline and follow-up samples of the two groups. These results indicate that xylitol-containing chewing gum inhibits the increase in total salivary bacteria over a short time during which the salivary microbial composition is not affected.

Quantification and qualification of bacteria trapped in chewed gum

Chewing of gum contributes to the maintenance of oral health. Many oral diseases, including caries and periodontal disease, are caused by bacteria. However, it is unknown whether chewing of gum can remove bacteria from the oral cavity. Here, we hypothesize that chewing of gum can trap bacteria and remove them from the oral cavity. To test this hypothesis, we developed two methods to quantify numbers of bacteria trapped in chewed gum. In the first method, known numbers of bacteria were finger-chewed into gum and chewed gums were molded to standard dimensions, sonicated and plated to determine numbers of colony-forming-units incorporated, yielding calibration curves of colony-forming-units retrieved versus finger-chewed in. In a second method, calibration curves were created by finger-chewing known numbers of bacteria into gum and subsequently dissolving the gum in a mixture of chloroform and tris-ethylenediaminetetraacetic-acid (TE)-buffer. The TE-buffer was analyzed using quantitative Polymerase-Chain-Reaction (qPCR), yielding calibration curves of total numbers of bacteria versus finger-chewed in. Next, five volunteers were requested to chew gum up to 10 min after which numbers of colony-forming-units and total numbers of bacteria trapped in chewed gum were determined using the above methods. The qPCR method, involving both dead and live bacteria yielded higher numbers of retrieved bacteria than plating, involving only viable bacteria. Numbers of trapped bacteria were maximal during initial chewing after which a slow decrease over time up to 10 min was observed. Around 10(8) bacteria were detected per gum piece depending on the method and gum considered. The number of species trapped in chewed gum increased with chewing time. Trapped bacteria were clearly visualized in chewed gum using scanning-electron-microscopy. Summarizing, using novel methods to quantify and qualify oral bacteria trapped in chewed gum, the hypothesis is confirmed that chewing of gum can trap and remove bacteria from the oral cavity.

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.

Design and applications of biodegradable polyester tissue scaffolds based on endogenous monomers found in human metabolism

Synthetic polyesters have deeply impacted various biomedical and engineering fields, such as tissue scaffolding and therapeutic delivery. Currently, many applications involving polyesters are being explored with polymers derived from monomers that are endogenous to the human metabolism. Examples of these monomers include glycerol, xylitol, sorbitol, and lactic, sebacic, citric, succinic, alpha-ketoglutaric, and fumaric acids. In terms of mechanical versatility, crystallinity, hydrophobicity, and biocompatibility, polyesters synthesized partially or completely from these monomers can display a wide range of properties. The flexibility in these macromolecular properties allows for materials to be tailored according to the needs of a particular application. Along with the presence of natural monomers that allows for a high probability of biocompatibility, there is also an added benefit that this class of polyesters is more environmentally friendly than many other materials used in biomedical engineering. While the selection of monomers may be limited by nature, these polymers have produced or have the potential to produce an enormous number of successes in vitro and in vivo.

Morphological changes in Streptococcus mutans after chewing gum containing xylitol for twelve months

Few studies have been conducted to evaluate the effect of xylitol on the virulence and morphology of Streptococcus mutans (S. mutans). This study was conducted to evaluate changes in the morphology and virulence of S. mutans in response to long-term consumption of gum containing xylitol. Participants were voluntarily recruited for a women's oral health prevention program, classified into two groups (a control and a xylitol group), and then followed for 1 year. Ten salivary samples were randomly selected from each group. Colony count, field emission scanning electron microscopy, and real-time reverse transcription polymerase chain reaction were used to analyze the characteristics of S. mutans. In the xylitol group, the colony counts of S. mutans decreased steadily over time. In addition, the adherence of the colonies in the xylitol group became weak, and the size of the colonies decreased compared to the control. The secretion of sticky substances from the surface of S. mutans colonies and gtfB gene expression also decreased in the xylitol group. These findings indicate that regular chewing of xylitol gum over a long period may lead to decreased gtfB expression, which can negatively affect the synthesis of extracellular polysaccharides by S. mutans, which could reduce the size and growth of S. mutans colonies and change their morphology as a result.

Influência do complexo flúor-xilitol no controle da placa dentária e do sangramento gengival em pacientes herbiátricos com aparelho ortodôntico fixo

OBJETIVO: avaliar os efeitos de um dentifrício contendo flúor/xilitol na redução da adesão da placa à estrutura dentária, bem como no índice de sangramento gengival, em portadores de aparelho ortodôntico fixo. METODOLOGIA: foram avaliados 22 jovens, com idade entre 14 e 17 anos. Após a quantificação inicial dos índices, os jovens receberam instruções de escovação e começaram a utilizar somente os dentifrícios da pesquisa. Houve uma divisão aleatória da amostra em dois grupos (A e B). Na primeira semana todos utilizaram um dentifrício padrão e a partir da segunda semana os jovens do grupo A receberam um dentifrício contendo flúor, enquanto os do grupo B receberam um dentifrício contendo o complexo flúor-xilitol, que utilizaram durante vinte e oito dias, quando foram novamente avaliados (T1). Para a segunda fase (T2) houve inversão dos dentifrícios. RESULTADOS: foram comparados os resultados intra-grupo e nos dois grupos houve redução estatisticamente significante entre as fases inicial e T1, inicial e T2 e entre T1 e T2. Já na comparação entre os grupos não houve diferença estatisticamente significante entre eles, embora o dentifrício contendo flúor/xilitol tenha proporcionado uma porcentagem de redução do índice de sangramento gengival maior que o dentifrício contendo apenas o fluoreto de sódio, principalmente entre as fases inicial e T2, onde a redução no grupo A foi de 90,13% e no grupo B foi de 78,84%. CONCLUSÃO: a utilização de dentifrícios contendo flúor e xilitol, associada à instrução e motivação, parece ser um recurso bastante promissor para a manutenção da saúde bucal nos pacientes ortodônticos.

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.

Six-month polyol chewing-gum programme in kindergarten-age children: a feasibility study focusing on mutans streptococci and dental plaque

AIM

To investigate the use of polyol-containing chewing gums in a day-care centre (kindergarten) setting as a means to affect the growth of mutans streptococci and dental plaque.

DESIGN

Over a period of six months, 123 five-year-old children chewed xylitol (X group), sorbitol (G group), or did not chew gum (C group). Consumption of xylitol, and sorbitol was 4.5 to 5.0 g per day and subjects consumed in five supervised daily chewing episodes four at the day-care centres and one at home.

METHODS

Interproximal dental plaque was sampled at baseline and after six months for a laboratory study of mutans streptococci counts. The Quigley & Hein plaque index procedure was used. Interviews and questionnaires elucidated the acceptability of the programme.

RESULTS

Parents and kindergarten personnel regarded the programme as an important, additional procedure to promote better oral health. The children regarded the use of chewing gum as a pleasurable experience. Compared with groups G and C, there was a statistically significant reduction of mutans streptococci in the interproximal plaque in the X group. The Quigley & Hein plaque index scores tended to decrease in the X group, while no such trend was observed in the G group.

CONCLUSIONS

Habitual use of relatively small daily quantities of polyol-containing chewing gum by young children may be regarded as an important additional caries-preventive procedure in a combined day-care centre and home setting. Especially xylitol-containing chewing gum may significantly reduce the growth of mutans streptococci and dental plaque which may be associated with dental caries.

The effect of polyol-combinant saliva stimulants on S. mutans levels in plaque and saliva of patients with mental retardation

The effect of chewable saliva-stimulants on Streptococcus mutans levels in dental plaque and paraffin-stimulated whole saliva among participants who were mentally disabled was investigated. Over 64-days, 98 participants chewed one of four saliva-stimulating tablets five times/day. The tablets contained one of the following: xylitol (X) or sorbitol (S), or 1:1 mixtures of xylitol and erythritol (XE) or sorbitol and erythritol (SE). Consumption of xylitol and sorbitol in Groups X and S was 5.4 grams/day/ subject, and of each polyol in Groups XE and SE, consumption was 2.7 g/day/subject. Interproximal dental plaque and stimulated whole saliva were sampled at baseline, at Day 36, and Day 64. There was a statistically significant reduction of S. mutans in plaque and saliva counts in Groups X and XE. The percentage of S. mutans in total streptococci increased significantly in dental plaque in Group S but decreased in the other groups. The results suggest that xylitol-containing saliva stimulants may be more effective than sorbitol-containing products in controlling some caries-associated parameters in people who are mentally disabled. Also a relationship may exist between the pentitol-type xylitol and S. mutans, and erythritol may exert a specific biochemical effect on this organism, although further studies are needed.

The effect of medicated chewing gums on oral health in frail older people: a 1-year clinical trial

OBJECTIVES

To determine the effects of a medicated chewing gum on the oral health of frail older people.

DESIGN

A controlled, double-blind trial using three groups based on random allocation of residential homes.

SETTING

Sixteen residential homes in West Hertfordshire, England.

PARTICIPANTS

One hundred eleven dentate subjects aged 60 and older who completed the 12-month study.

INTERVENTION

Subjects were assigned to a chlorhexidine acetate/xylitol gum (ACHX) group, a xylitol gum (X) group, or a no-gum (N) group. Subjects in the gum groups chewed two pellets for 15 minutes twice daily for 12 months.

MEASUREMENTS

Primary outcome measures were salivary flow rate, denture debris score, prevalence of angular cheilitis, and denture stomatitis; secondary outcome measures were salivary levels of caries-associated microorganisms. A single examiner, who was blinded to group allocation, made all measurements at baseline before gum usage and at subsequent examinations after 3, 6, 9, and 12 months. Separate analyses were performed for subjects with dentures.

RESULTS

Subjects in the three groups were similar in most of their baseline characteristics. The stimulated whole saliva flow rate +/- standard deviation increased significantly for the ACHX (1.4 +/- 0.7 mL/min) and X (1.6 +/- 0.9 mL/min) groups (P <.01) over baseline (ACHX = 0.9 +/- 0.6 mL/min, X = 0.8 +/- 0.6 mL/min) and N group levels (0.6 +/- 0.9 mL/min). The levels of mutans streptococci, lactobacilli, and yeasts significantly increased (P <.05) in the X and N groups. Denture debris status was significantly lower in the ACHX and X groups than at baseline or in the N group (P <.01). The reductions of 91% and 75% in denture stomatitis and angular cheilitis prevalence, respectively, that occurred in the ACHX group were significantly greater (P <.01) than the reductions in the X group (denture stomatitis 62%, angular cheilitis 43%). Prevalence of denture stomatitis and angular cheilitis were not significantly changed in the N group.

CONCLUSION

The use of a medicated chewing gum significantly improved oral health in older occupants of residential homes. Chewing gums should be considered as a potential adjunct to other oral hygiene procedures in older subjects.

Xylitol disturbs protein synthesis, including the expression of HSP-70 and HSP-60, in Streptococcus mutans

Xylitol, a natural sugar alcohol and a caries-preventive carbohydrate sweetener, inhibits xylitol-sensitive wild-type Streptococcus mutans but also selects for its natural xylitol-resistant mutants. The aim of the work was to verify the influence of xylitol on heat shock proteins HSP-60 (GroEL-like) and HSP-70 (DnaK-like) in xylitol-sensitive and xylitol-resistant strains. Cells from fresh isolate S. mutans 123.1 were grown at 37 degrees C and constant pH 7.0. The cell culture was stressed by raising the temperature to 43 degrees C or adding xylitol (4% final). Cell proteins labeled with a cocktail of 14C-amino acids were analyzed by SDS-PAGE and autoradiography whereas HSP-60 and HSP-70 were visualized using Western immunoblotting. In both xylitol-sensitive and xylitol-resistant strains, heat stress was associated with an increase of both HSP-60 (63 kDa) and HSP-70 (71 kDa) and a decrease in the intensity of a number of other protein bands compared with cells maintained at 37 degrees C. Exposure to xylitol but not to other polyols induced a decrease of both these heat shock proteins in the xylitol-sensitive strain but did not modify them in the xylitol-resistant mutant. It also decreased all protein bands above 60 kDa together with a 53 kDa protein and increased the amount of 57-, 50- and 40-kDa proteins in the xylitol-sensitive strain whereas the proteins of the xylitol-resistant strain remained unchanged. The results suggest that xylitol is a strong metabolic inhibitor that disturbs protein synthesis and reduces the expression of HSP-70 and HSP-60 proteins in the wild-type xylitol-sensitive S. mutans but not in the xylitol-resistant natural mutant strain.

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.

Carbamide-containing polyol chewing gum and prevention of dental caries in schoolchildren in Madagascar

The objective of this investigation was to evaluate the effect on dental caries experience of using carbamide polyol chewing gum as a supplement to standard oral hygiene procedures for schoolchildren in a developing country (Madagascar). In 1994, grades 1 and 4 children of demonstration schools were allocated to experimental and control groups; all children participated in a school-based oral health education programme, including daily toothbrushing supervised by the classroom teacher. At grade 1, the test group (n = 125) also used chewing gum (V6: 55.5 per cent sorbitol, 4.3 per cent xylitol, 2 per cent carbamide) three times a day. At grade 4, one test group (n = 177) had chewing gum three times a day and an additional test group (n = 74) had chewing gum five times a day. The control groups included 117 children at grade 1 and 209 at grade 4. Dental caries was registered in 1994 and 1997 according to the Recording System for the Danish Child Dental Services. In grade 1 children, the preventive effect of the total DMFS was not statistically significant except for occlusal caries (-0.65 DMFS, P < 0.01). In the grade 4 test groups, non-significant reductions of dental caries experience were found when compared with controls. The present community trial indicates that the use of polyol chewing gum may be considered a supplement to the control of occlusal dental caries in young primary schoolchildren, particularly in developing countries with limited resources for dental care.

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.

Effect of three months' frequent use of sugar-free chewing gum with and without urea on calculus formation

Studies on the relationship between gum-chewing and calculus formation have produced contradictory results, and it is not clear whether frequent use of chewing gum promotes or inhibits calculus formation. Also, little is known about whether the addition of a small amount of urea to the chewing gum influences calculus formation. The aim of this investigation was to study the effect of sugar-free chewing gum--with and without urea--on calculus formation and some associated clinical variables. Three three-month periods were studied in a double-blind, crossover design, during which the subjects: (1) chewed 5 pieces/day of a sugar-free, urea-containing chewing gum (20 mg urea/piece); (2) chewed 5 pieces/day of a sugar-free, non-urea-containing gum; or (3) performed no gum-chewing. Twenty-nine persons, all calculus-formers, participated. They were scored for calculus at mesio-lingual, lingual, and disto-lingual sites on the 6 anterior mandibular teeth according to the Volpe-Manhold index. Plaque and gingival bleeding index, stimulated salivary secretion rate and buffer capacity, resting plaque pH, mutans streptococci in saliva and plaque, and lactobacilli in saliva were also determined. No differences in calculus formation were found among the 3 periods. The resting plaque pH was higher after the period with urea-containing gum than after the period with non-urea-containing gum and the no-gum period (p < 0.05). A slight increase in stimulated salivary secretion rate was found after the 2 gum periods (p < 0.05). The plaque and gingival bleeding indices decreased, while resting plaque pH and salivary buffer capacity increased throughout the entire study (p < 0.05). No significant differences in prevalence of the acidogenic micro-organisms were found among the test periods. The main conclusion from this study is that three months' frequent use of sugar-free chewing gum--with or without urea--neither promotes nor inhibits calculus formation.

The effects of xylitol-containing chewing gums on dental plaque and acidogenic potential

The aim of this study was to test the hypothesis that the chewing of xylitol- or xylitol/sorbitol-containing chewing gum reduces plaque formation and the acidogenic potential of dental plaque. Thirty healthy volunteers aged from 19 to 28 yrs were randomly allocated to one of three test groups, chewing either xylitol-, xylitol/sorbitol-, or sucrose-sweetened gums. A three-day plaque accumulation period of no oral hygiene was instituted prior to and at the termination of the chewing gum program, which lasted 33 days. Plaque quantity was assessed on the basis of protein content of individual plaque samples collected by a standardized technique. Acidogenic potential of individual baseline and test plaque samples was assessed by the quantity of various organic acids formed from D-(U-14C)glucose. Identification of extracellular and intracellular metabolites was performed by HPLC. Statistical evaluation of data was performed according to paired comparisons of individual baseline and post-chewing data. Plaque formation, acidogenic potential, and glycolytic profiles were similar at baseline and after the gum-chewing periods. Also, there was no intracellular accumulation of glycolytic metabolites within the plaque bacteria to indicate the inhibition of glycolysis. The study thus leads to the conclusion that, in young adults with low caries experience, exposure of the oral cavity to acceptable doses of xylitol or xylitol and sorbitol has no effect on the microbial deposits on the teeth.

Physical, chemical, and histologic changes in dentin caries lesions of primary teeth induced by regular use of polyol chewing gums

A previous clinical trial showed that long-term use of saliva-stimulating polyol (xylitol and sorbitol) chewing gums was associated with arrest of dental caries in young subjects. After a 20-22-month intervention (when the subjects were 8 years old), a total of 23 primary teeth with extensive dentin caries lesions whose surface in clinical examination was found to be totally rehardened (remineralized) could be removed because the teeth were near their physiologic exfoliation time. These teeth were subjected to histologic, microhardness, and electron microscopic tests. The majority of the specimens had been remineralized from the surface by a non-cellular-mediated process within the remaining collapsed, organic extracellular matrix associated with the remaining dentinal surface. Many of the underlying dentinal tubules were filled with a matrix that had been subsequently mineralized. Dental microanalyses showed that the topmost (outer) 20-microm-thick rehardened layer of the lesions exhibited the highest Ca:P ratio, which leveled off at a depth of approximately 150 microm. The rehardened surface layer (normally <0.1 mm in thickness) was significantly (P < 0.001) harder than sound dentin and nearly as hard as sound enamel. Although the main source of the mineral present in the rehardened layer was most likely of salivary origin, some extracellular remineralization was probably mediated by odontoblasts. The results complete the dinical diagnoses of the original trial and suggest that regular use of polyol chewing gums may induce changes in dentin caries lesions, which in histologic and physiochemical studies show typical characteristics of rehardening and mineralization.

Polyol-combinant saliva stimulants: a 4-month pilot study in young adults

Several studies indicate that xylitol (X) consumption is associated with certain biochemical changes in dental plaque and whole saliva. In making X-containing saliva stimulants more cost-effective and palatable, manufacturers may use maltitol syrup (MS, which normally contains some sorbitol and higher polyols) or polydextrose (PD, a polysaccharide molecule with a mass > 22 kDa) as bulking agents. Combinations of X with MS and PD have not been tested regarding their salivary effects. One hundred and eighty-eight young subjects (mean age, 22 years) of both sexes were divided into three groups of equal size for a 4-month study. The subjects in one group used X-MS dragees (in 7 daily episodes; 8 g X per day), while the subjects in another group used X-PD dragées in as many daily episodes (8 g X per day). Subjects in the third (comparison) group did not receive saliva stimulants. Paraffin-stimulated whole saliva samples were collected at baseline, after 2 months, and at endpoint. The usage of X-MS was associated with a significant (P < 0.05) reduction in the salivary sucrase activity. After 4 months, the activity of enzymes hydrolyzing N(alpha)-benzoyl-DL-arginyl-p-nitroaniline was significantly reduced in all groups, while the levels of free sialic acid were reduced in group X-PD only (P < 0.05). These salivary changes most likely reflected microbial shifts in the oral cavity and suggest that information from saliva studies may be of avail when deciding which bulking agents should be used in xylitol-based saliva stimulants.

Effect of xylitol in an enzyme-containing dentifrice without sodium lauryl sulfate on mutans streptococci in vivo

The aim of this investigation was to compare the effect of an enzyme-containing dentifrice without sodium lauryl sulfate but with addition of xylitol (Zendium Dentine) on mutans streptococci (MS) in saliva and dental plaque with that of the same dentifrice without xylitol. The subjects were divided into a test group, using a dentifrice with 10% xylitol (part A) or 5% xylitol (part B), and a control group, using a dentifrice without xylitol, for 3 months. In part A the MS counts in saliva and plaque were significantly lower in the xylitol group (n = 50) than in the control group (n = 57) (P < 0.01 and P < 0.001, respectively). In part B (n = 89 + 91), evaluating MS counts in saliva only, no significant difference was found. Thus, this study demonstrated I) that addition of 10% xylitol to an enzyme-containing dentifrice without sodium lauryl sulfate has an inhibitory effect on MS counts in saliva and dental plaque, and 2) that the inhibitory effect seems to be dose-dependent.

Sugar, alternative sweeteners and meal frequency in relation to caries prevention: new perspectives

In the last 20 years, mainly due to optimum fluoride exposure, and practice of good oral hygiene procedures, an important reduction in caries has been observed, despite the fact that sugar consumption was maintained and/or was increasing during the same lapse of time. A sugar-caries relationship cannot be established in most of the industrialized countries and the dietary factor is not as preponderant in the caries process as it used to be two decades ago. The factors which seem to contribute the most significantly to the cariogenicity of the diet are the frequency of carbohydrate ingestion and eating patterns. The relative cariogenicity of food is not correlated with the amount of carbohydrate it contains. Even if sucrose remains the most important sugar consumed in sweets, beverages and confectionery products, all fermentable-carbohydrate foods can be involved in the caries process. The use of chewing gum and other xylitol-containing products have resulted in defined reduction in caries and represent interesting alternatives for high-caries-risk populations. Caries risk and oral health assessments as well as the evaluation of oral hygiene procedures and fluoride exposure should become essential tools in dietary counselling. People who receive optimum fluoride exposure and follow regular oral hygiene measures can safely use dietary carbohydrates, preferably during meals and two to three times daily in snacks or drinks.

Effects of xylitol, xylitol-sorbitol, and placebo chewing gums on the plaque of habitual xylitol consumers

Xylitol reduces plaque but the reduction mechanism is largely unknown. The main aim of the present study was to determine whether the xylitol-induced reduction in the amount of plaque and the number of mutans streptococci could be demonstrated in subjects with (presumably) high levels of xylitol-resistant (XR; not inhibited by xylitol) mutans streptococci acquired following previous xylitol consumptions. 37 healthy dental students participated in the double-blind study. All subjects had been uncontrolled, habitual consumers of xylitol-containing products for at least 1 yr before the study. A 1-month washout period was followed by a 2-week test period during which either xylitol, xylitol-sorbitol or unsweetened chewing gum base was chewed 3-5 x a day. Plaque and saliva samples were collected at baseline and at the 2-week point for determination of the amount of plaque, microbiological variables, and hydrolytic enzymes. Mixtures of xylitol and sorbitol seemed to perform equally well with respect to reduction in the amount of plaque but not the number of mutans streptococci. Thus, polyols were the active ingredients of chewing gums able to modulate the amount of plaque and its microbial composition. Xylitol reduced plaque with a mechanism which appeared not to be associated with the study-induced changes in the proportion (%) of mutans streptococci in plaque, the number of salivary mutans streptococci, the proportion of XR strains in plaque or saliva, or the hydrolytic enzyme activities of plaque.

Effects of frequent mouthrinses with palatinose and xylitol on dental plaque

The aim was to evaluate the effects of frequent mouthrinses with palatinose, xylitol and a mixture of palatinose and xylitol on plaque pH, plaque formation and cariogenic microorganisms. 15 subjects refrained from toothbrushing during 3 test periods and rinsed 15 x daily for 4 d with 10 ml of: (1) 50% palatinose, (2) 37.5% palatinose + 12.5% xylitol, or (3) 50% xylitol. A contrast period with no mouthrinses was also carried out. The 4 periods were carried out in a randomized order with a cross-over design. After the 4-day periods, 3 parameters were measured: (1) plaque pH during the first 30 min after a mouthrinse with palatinose, a mixture of palatinose and xylitol or xylitol alone, directly followed by a 2nd rinse with 10% sucrose; (2) number of mutans streptococci and lactobacilli in plaque and saliva; (3) plaque index. The most pronounced pH drop for the sugar substitutes was found when rinsing with 50% palatinose after the palatinose period, and the least pH drop with 50% xylitol after the xylitol period. The sucrose rinse gave similar pH fall after all 4 periods. The microbial data showed no differences between the 4 periods, but the mutans streptococcus counts in saliva decreased after the xylitol period in contrast to the 3 other periods. Regarding the plaque index, xylitol gave lower scores compared to the other 3 periods.

Timing of first restorations before, during, and after a preventive xylitol trial

An independent longitudinal retrospective analysis of the timing, number, and cost of tooth restorations was conducted for all subjects (n = 313) in the age cohort of a municipal health center, in which two consecutive field trials of up to 3 years on the caries-preventive effect of the use of xylitol chewing gum were conducted (Ylivieska study, 1982-85). A computer program calculated the post-eruptive timing of the first restorations on each permanent tooth surface, and survival analysis methods were applied before, during, and after the trials. The cost of restorations was then calculated. The total number of new restored surfaces was 4.0 per child in the xylitol group and 9.3 in the controls during the decade after onset of the trial. The number of restorations on the occlusal surfaces of the first molars leveled off at 40-50% in the xylitol group and at about 60-70% in the control group. Plateaus for the second molars were at 30-40% and 60-70%, respectively. The time lag for the first restorations was longer in the xylitol group for the proximal and other smooth surfaces. A marked difference in favor of the xylitol group was observed in the proximal surfaces of the upper incisors (for example, the mesial surface of the upper mesial incisor for girls: log-rank chi-square = 11.1, p < 0.001). The preventive effect was most pronounced in teeth that had erupted during the trial. This analysis indicated that participation of subjects in the xylitol chewing gum trials resulted in a significant reduction in the number of first restorations and hence in costs during the decade after the onset of gum use.

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.