Streptococcus Mutans Count Research Articles

The Effect of Xylitol on the Composition of the Oral Flora: A Pilot Study

Our aim was to investigate the effect of short-term xylitol consumption on the microbial composition of plaque and saliva. Twelve volunteers (22-38 yrs) harboring mutans streptococci (MS) participated in the randomized, double-blind, cross-over study. The experimental chewing gum contained 65% xylitol while the control gum contained 63% sorbitol and 2% maltitol w/w. The polyol dose was approximately 6 g/day. Stimulated saliva and plaque samples were collected before and after the two four-week test periods. The samples were cultured for MS, total streptococci, lactobacilli, and total facultatives. A part of the samples were subjected to DNA-DNA hybridizations of 14 microbial plaque species: Actinomyces naeslundii, A. viscosus, Fusobacterium nucleatum, Lactobacillus acidophilus, L. fermentum, L. paracasei, L. rhamnose, L. plantarum, Streptococcus gordonii, S. oralis, S. parasanguis, S. salivarius, S. sanguinis, Veillonella parvula. The MS counts of the plaque samples collected from "caries-prone" tooth sites decreased significantly (P<.01) in the xylitol gum group but not in the sorbitol gum group. Also the plaque MS percentage decreased significantly in the xylitol gum group (P<.01). The salivary MS counts did not decrease either in the xylitol or in the sorbitol gum groups. Nor were changes detected in the salivary levels of total streptococci or lactobacilli. The DNA-DNA hybridization assay revealed no study-induced changes in the microbial composition of the dental plaque. Within the limitations of this pilot study, xylitol consumption reduced MS counts in plaque but appeared not to affect the microbial composition of plaque or saliva in general.

Association between Socioeconomic Status, Salivary Streptococcus mutans, Lactobacilli and Dental Caries among 12-Year-Old School Children in Belgaum City

ABSTRACT Introduction Aim of the study was to assess dental caries using Modified Dentition Status and Treatment Needs and find its association with salivary Streptococcus mutans and lactobacilli counts among 12-year-old school children of Belgaum city. Materials and methods A self-designed, 13 item, open-ended questionnaire given to parents. Children were examined for dental caries using Modified Dentition Status and Treatment Needs. Stimulated saliva was collected and incubated to estimate lactobacilli and Streptococcus mutans colonies. Chi-square test was used to find the association between variables. Results When DMFT was recorded it was found that 23% of children were free from dental caries, whereas, only 5% of them were free of dental caries when examined using modified criteria. Most of the children had higher microbial count with 72% and 62% of them having &gt; 105 cfu/μl of Streptococcus mutans and lactobacilli colony count respectively. Modified DMFT was significantly associated with frequency of brushing, lactobacilli and Streptococcus mutans counts (p &lt; 0.05). Conclusion The proportion of subjects with dental caries was relatively high in all groups but the number of teeth affected by caries was low. Inclusion of noncavitated incipient lesions could increase sensitivity of index.

Effects of oral environment stabilization procedures on Streptococcus mutans counts in pregnant women

The aim of this study was to determine the effect of oral environment stabilization (OES) on the counting of Streptococcus mutans in high-caries-risk pregnant women participants of a prevention program in a public teaching institution. The sample was composed of 30 pregnant women aged 18 to 43 years, who looked for treatment at the Preventive Dentistry Clinic of the Araraquara Dental School, UNESP. Saliva samples were collected before and after the OES procedures and were forwarded to the pathology for observation and quantification of S. mutans CFU. There was a decrease in the number of S. mutans CFU, which was significantly different (p<0.0001) between samples. Considering the age group, 70.0% were between 18 to 30 years old and 30.0% belonged to the 31-43-year-old age group. Data related to the pregnancy period showed that 73.4% were in the second trimester, 13.3% in the first and 13.3% in third trimester. OES showed to be an effective clinical procedure in diminishing the number of S. mutans CFU in the saliva of high-caries-risk pregnant women. This management is simple and effective, corresponding to the basic treatment needs of pregnant women that search dental care in this public service.

Effects of Xylitol on Survival of Mutans Streptococci in Mixed-Six-Species in vitro Biofilms Modelling Supragingival Plaque

Xylitol has been claimed to reduce mutans streptococci (MS) in dental plaque by energy-consuming futile metabolic cycles. This study aimed to investigate the effects of xylitol on MS in an in vitro 6-species oral biofilm model. Each multispecies biofilm contained either a laboratory reference strain, a fresh isolate, a xylitol-sensitive or a xylitol-resistant strain of Streptococcus mutans or Streptococcus sobrinus. Biofilms, grown on pellicle-coated hydroxyapatite discs, were fed with a glucose/sucrose-supplemented medium 3 times daily for 45 min and incubated in saliva between feedings. Before or after feeding, biofilms were exposed to either 7.5% xylitol, 7.5% sorbitol or to saliva (control) for 20 min. After 64.5 h, biofilms were harvested and the microbial composition was analysed by non-selective and selective culturing. Strain variability in the ability to colonize biofilms was observed. However, the response patterns in the biofilms to the 4 polyol treatments were similar. None of the MS were inhibited by xylitol provided either before or after feeding. Sorbitol given before feeding did not affect microbial growth whereas sorbitol provided after feeding showed a slight, albeit statistically significant increase in MS counts for some of the tested strains. It did so at the expense of Streptococcus oralis, which decreased in numbers. The present findings do not support the contention that xylitol reduces MS in plaque by futile metabolic cycles.

Clinical reduction of S. mutans in pre-school children using a novel liquorice root extract lollipop: a pilot study

To determine the clinical effect of a simple herbal caries-prevention protocol aimed at reduction of Streptococcus mutans (SM) in young children in a pre-school setting. Proof-of-principle pilot study. To prove the concept this pilot study delivered a clinical intervention using sugar-free lollipops containing liquorice root extract. Regimen: Supervised herbal lollipops, twice daily for 3 weeks. Species-specific monoclonal antibody testing of saliva provided SM counts. Children were grouped in high, medium and low caries-risk using baseline SM-levels as risk-indicator. Bacterial numbers at baseline, during intervention, and for 9 weeks post-intervention were compared. SM levels were analysed using GEE modelling. High-risk children showed the steepest early decrease in mean log-SM (P<.001). At end of a follow-up period, the log-SM decrease moved the high-risk group down to moderate-risk level. High-risk children showed a decrease in fitted mean SM% not seen in other groups (P<.001). The decrease reached a nadir around 22-days post-intervention. Twice-daily use of herbal lollipop significantly reduced both number and relative percent of SM in high-risk children. SM numbers were reduced for 22 days after the last lollipop, stabilized and then began to rebound. A potential for simple effective caries-prevention for high-risk children has been demonstrated. Encouraging results warrant randomised clinical trials (RCT) of liquorice root in herbal lollipops or alternative modes of delivery.

Effects of Lactobacillus rhamnosus GG on saliva-derived microcosms

Objective The probiotic strain Lactobacillus rhamnosus GG (LGG) is shown to hamper the presence of mutans streptococci in saliva and may have positive effects on oral health. We investigated the effects of LGG on the cariogenic potential and microbial composition of saliva-derived microcosms. Design Single and dual species biofilms of LGG and Streptococcus mutans, and saliva-derived microcosms with or without LGG were grown in an Active Attachment Biofilm model. The microcosms were grown on bovine dentin/enamel discs in the presence or absence of sucrose (suc+/suc−). The presence of LGG was determined by multiplex ligation-dependent probe amplification (MLPA) and real-time PCR. Mutans streptococci (MS) and total viable counts, pH of the spent medium, capacity of lactate formation and integrated mineral loss in dentin was assessed. MLPA was used for identification and relative quantification of 20 oral microorganisms in the microcosms. Principal Component Analysis was applied to MLPA data. Results LGG inhibited the growth of S. mutans in dual species biofilms and did not affect the pH. LGG established in saliva-derived microcosms and reduced MS counts significantly, but did not affect pH or dentin demineralization. Simultaneous growth of the microcosms with LGG under heavy cariogenic conditions (suc+) introduced a compositional shift in the microbial community. The CFU, real-time PCR and MLPA data correlated significantly. Conclusion We conclude that LGG established into and inhibited the growth of MS in complex saliva-derived biofilms, but this had no significant effect on cariogenic potential of the microcosms. This suggests that other microorganisms besides MS were responsible for increased cariogenicity of sucrose-exposed biofilms.

Mutans Streptococci and Caries Prevalence in Children after Early Maternal Caries Prevention: A Follow-Up at Eleven and Fifteen Years of Age

Aim: The efficacy of early maternal caries prevention in children was evaluated. Methods: First-time mothers selected on the basis of a high level of salivary mutans streptococci (MS) and mothers excluded at screening due to a low level of MS (‘low’) were recalled when their children were 11 years old. The salivary MS level was determined in the mothers. Their children were examined for salivary MS and lesion prevalence (decayed and filled surfaces, DFS) at the ages of 11 and 15 years. Results: More ‘high control’ mothers displayed ≧10⁶ MS than the ‘high interventional’ and ‘low control’ mothers and, vice versa, more ‘interventional’ and ’low control’ mothers had MS counts of <3 × 10⁵ than ’high control’ mothers. More of ‘interventional’ and ’low control’ children had <10⁵ MS/ml as compared with the ’high control’ children. All the ’high control’ children had detectable MS. MS were undetected in 5 ‘interventional’ and 5 ’low control’ children at 15 years. Significantly fewer ’high control’ than ‘interventional’ and ’low control’ children were caries free at 11 and 15 years of age. Non-MS-colonised children at 3 years of age, irrespective of group identity, displayed statistically lower MS counts and less DFS at 15 years than those colonised at 3 years of age. Children with clinical caries/fillings at 15 years had had a significantly higher level of MS at 11 years of age than those without clinical caries/fillings. Conclusion: The clinical trial, focusing on the mothers, resulted in long-term benefits for their children. Children colonised by MS at an early stage developed more caries than those colonised at a later stage.

Antimicrobial Effectiveness of Chlorhexidine Chewing Gums on Streptococcus Mutans Counts– An in vivo Microbiological Study

The aim of the present study was to evaluate the antimicrobial efficacy of Chlorhexidine chewing gums and to assess the effect of dosage and frequency of intake of Chlorhexidine gums on Streptococcus mutans (SM) count. The sample consisted of 30 subjects, divided into two groups AI & AII. Each group consisted of 15 subjects. Group AI chewed 2 Chlorhexidine Chewing gum X Twice Daily for 20 minutes (Total = 4 gums Daily) & Group AII chewed 2 Chlorhexidine Chewing gum X Four times daily for 20 minutes (Total = 8 gums Daily) & saliva sample was collected & agar plates were inoculated for SM colony count. The study was carried for a week's time and salivary sample collected were Baseline, Day 1 morning and evening, Day 4 evening, Day7 morning and evening. After the gum was chewed, it was observed that the colony count started to decrease when compared with baseline in both the groups. The fall in SM count was statistically highly significant with p < 0.001 in both the groups. When comparing between Group AI (Dosage 20 mg daily) and Group All (Dosage 40 mg daily), the fall in SM count for both the groups was not statistically significant with p-value > 0.05. It was concluded that there was reduction in the level of Salivary SM, but was not statistically significant, by increasing the dosage and frequency of intake of Chlorhexidine containing gums. We recommend that dosage of Chlorhexidine containing chewing gums can be restricted to four gums instead of eight gums per day.

Potential effects of a multistrain probiotic-kefir on salivary Streptococcus mutans and Lactobacillus spp.

Background/purpose It has recently been documented that various probiotic formulations have beneficial effects in reducing caries risk as well as promoting human health. The aim of the present study was to examine the efficacy of short-term consumption of a multistrain probiotic-kefir on salivary counts of Streptococcus mutans and Lactobacillus spp. in young adults. Materials and methods In total, 104 subjects aged 20-27 years were included in the study. The salivary flow rate, buffer capacity, salivary mutans streptococci and lactobacilli counts were detected in each subject after a 3-week washout period using chair-side kits at baseline. Subjects were randomly assigned into three groups: Group I consumed 100 mL kefir per day ( n = 35); Group II consumed 2 ± 100 mL kefir per day ( n = 35); and Group III consumed 100 mL milk (n = 34). A questionnaire investigating the oral and dietary habits of the subjects was also filled out by each subject. After 3 weeks of consumption of the experimental materials, salivary mutans streptococci and lactobacilli counts were reevaluated. Results Statistically significant reductions were observed in both salivary mutans streptococci and lactobacilli in Group II compared to the baseline (P = 0.001 and P=0.01, respectively). Conclusion Short-term consumption of kefir might reduce high levels of salivary mutans streptococci and lactobacilli.

Association between biofilm-forming isolates of mutans streptococci and caries experience in adults

Objectives Although it is still controversial, mutans streptococci (MS) have been typically considered the primary etiological agents of dental caries. Besides the acidogenic and aciduric properties, extracellular polysaccharide synthesis leading to biofilm formation from sugar constitutes one of the key virulence factors of MS. The aim of this study was to investigate whether biofilm formation by MS was associated to an increased experience of caries in young adults. Methods A cross sectional study with a total of 96 randomly selected patients aged 15–27 years old was carried out. DMFT was determined by clinical examination and bite-wing radiographs. A sample of stimulated saliva was obtained and seeded on agar plates to culture MS. Colonies with and without biofilm formation were identified and quantified. Results When the total MS count was considered, levels of MS were not associated with higher caries experience. 50% of the patients showed at least one biofilm-forming colony. Patients with biofilm-forming colonies showed significantly higher DMFT ( p < 0.001) than individuals whose plates did not reveal the structure surrounding the colony, but only at the low and moderate MS count. Conclusion Biofilm formation in MS appears to be associated with higher caries experience in individuals with low counts of the cariogenic microorganism.

Caries Risk Factors in Children under Treatment with Sectional Brackets

To longitudinally investigate the caries risk levels in children undergoing orthodontic treatment with sectional brackets. A total of 42 children scheduled for orthodontic treatment with sectional orthodontic appliances participated in this study. They were divided into two groups based on decayed, missing, and filled permanent and deciduous teeth (DMFT/dmft) scores and counts of mutans streptococci (MS) prior to treatment. One was the low caries risk group (n = 26) and the other was the high caries risk group (n = 16). Paraffin-stimulated whole saliva was collected for examination of salivary flow rate, buffer capacity, and MS and lactobacilli (LB) levels before treatment, 2 and 4 months after appliance placement, and 2, 4, and 8 months after appliance removal. The pretreatment salivary flow rates, buffer capacity, and MS levels remained statistically unchanged during and after active orthodontic treatment in both groups. The levels of LB in the high caries risk group were significantly elevated by appliance placement, but upon appliance removal started to fall significantly and came a little short of the pretreatment levels. In the low caries risk group, the pretreatment levels of LB remained statistically unchanged during and after treatment. There were no significant differences in salivary flow rate or buffer capacity, but there were significant differences in MS and LB scores between the two groups at every measurement time. In children undergoing orthodontic treatment with sectional brackets, LB levels are an important part in making caries risk assessment.

Availability of air powder polishing with crystalline cellulose as a prophylactic method for orthodontic patients with a multi-bracket appliance

The aim of this study was to comparatively evaluate the air powder polishing (APP) system with crystalline cellulose with the rubber cup and pumice (RCP) method as prophylactic methods in orthodontic patients. This study included two examinations. First, 58 orthodontic patients were randomized into the APP group or RCP group, and the changes in the colony counts of salivary mutans streptococci (MS) assessed before and after the prophylactic treatment were evaluated. Assessment of MS was conducted three times: immediately before the treatment (Test 1), immediately after the treatment (Test 2), and 1 month after the treatment (Test 3). The samples were inoculated on modified Mitis-Salivarius-Bactracin (MSB) agar plates. Under the microscope, the colonies were counted. In the second experiment, using a randomized split-mouth design, half the mouths of 8 patients were treated with APP and the contralateral side with RCP by three dentists, and then the time required for plaque removal was compared. Significant reduction in the colony count of MS in the saliva was observed in both the APP and RCP groups. However, the count of MS returned to the baseline level after 1 month in both groups. APP removed dental plaques in less time than RCP. APP with crystalline cellulose is a clinically available prophylaxis method for orthodontic patients, and appears to succeed in removing the plaque more quickly.

There are no Clearly Superior Methods for Diagnosing, Predicting, and Noninvasively Treating Dental Caries

To be included in the systematic review, all articles were required to meet predetermined criteria: the results of the studies should be relevant to the questions posed by the project, ie, have appropriate outcome measures and an appropriate follow-up period and study design. With respect to diagnosis, the efficacy of the various methods was compared with reference methods that included studies of extracted teeth. For prediction, the material comprised mainly prospective studies, where the reliability of risk assessment could be evaluated. With respect to treatment of early caries lesions, it was a requirement for inclusion that the study had a control group. For caries detection of accessible surfaces, visual-tactile testing was used. Radiographic diagnosis was used for approximal surfaces. For caries risk prediction, modeling was used to determine the influence of specific variables (eg, sugar intake). For noninvasive treatment assessment, size of lesion growth or shrinkage after treatment was used. Caries detection: Visual-tactile detection for accessible surfaces carried the best, but far from optimal, accuracy. Although specificity tends to be high with this method, sensitivity is low. Caries risk prediction: Streptococcus mutans count, salivary Lactobacillus count, salivary buffering capacity, visible plaque levels, and sugar intake have low accuracy. The best, but still far from optimal, predictor was past caries history. Noninvasive methods of caries treatment: Too few studies exist for meaningful analysis. (1) Past caries is the best predictor of future caries. (2) A combination of visual-tactile and radiographic examination is better than either method alone. (3) There is insufficient evidence to support noninvasive treatment of early caries. STUDY OBJECTIVE AND METHODS: To perform a systematic review of published literature to (1) determine the evidence for the effectiveness of different methods (visual-tactile versus radiographic) for detecting caries; (2) identify the most prescient predictors of dental caries; and (3) evaluate the evidence supporting the use of noninvasive methods for the treatment of caries, particularly early caries. With regard to the questions posed by the study team: (1) Past caries is the best predictor of future caries; (2) a combination of visual- tactile and radiographic examination is better than either method alone; and (3) there is insufficient evidence to support noninvasive treatment of early caries.

Microbiological evaluation of salivary Streptococcus mutans from children of age 5-7 years, pre- and post-atraumatic restorative treatment

Background and Objective:The objective of the study was to monitor Streptococcus mutans (SM) counts in saliva of children aged 5-7 years old over a period of 6 months with the subsequent use of Fuji IX, glass ionomer cement in atraumatic restorative technique (ART).Materials and Methods:One hundred children were selected to receive ART using Fuji IX glass ionomer cement. Caries status was recorded using DMFT index (WHO 1997) and revaluated after 6 months using DMFS index (WHO 1979). Saliva was collected for microbiological assessment of SM count on four occasions, baseline, 1 week, 1 month, and 6 months after ART approach. The results of the microbiological tests were statistically analyzed using the non-parametric Mann-Whitney rank test.Results:The results showed a significant reduction of SM levels in saliva immediately 1 week following the ART approach with mean SM counts of 1.5763 (106 CFU/ml) and 1.1286 (105 CFU/ml) pre- and 1 week post–ART, respectively. Reduction in the SM count was seen in 89.47% of children after 1 week of ART treatment. The mean SM count after 1 month and 6 months post-ART was 1.4814 (106 CFU/ml) and 1.4722(106 CFU/ml), respectively.Conclusion:It was concluded from the results that the ART technique was successful in reducing the SM counts in saliva significantly for a period of 1 week post treatment. Although the mean SM counts remained less than the baseline after 6 month evaluation, a trend toward re-establishment of SM to the baseline count was noticed.

Influence of Type of Prosthesis on Oral Environment and the Number of Missing Teeth in Elderly Persons

The purpose of this study was to investigate the relationship between the number of missing teeth (MT) and the statuses of oral environmental factors (the stimulated salivary flow rate, buffering capacity, and the counts of mutans streptococci, lactobacilli, and Candida) in the elderly. The subjects were 64 elderly subjects with fixed prostheses and 49 who wore removable partial dentures aged over 65 years. We used one-way ANOVA to test for overall differences of the number of MT among 5 oral environmental factors. The significant differences were observed in the lactobacilli counts for different number of MT. The number of MT increased with an increase in the lactobacilli counts with removable denture. In conclusion, for the patients wearing removable dentures, increasing number of MT was associated with an increase in the lactobacilli counts in saliva. For the patients with crowns and fixed partial dentures, the number of MT was not significantly affected by salivary mutans streptococci, lactobacilli, and Candida counts.

Salivary Characteristics in a Sample of Preschool Children with Severe Early Childhood Caries (S-ECC)

The aim of this study is to investigate the salivary counts of mutans streptococci and lactobacilli, as well as measure the saliva buffering capacity and salivary flow rate in a sample of preschool children with severe early childhood caries in Jeddah, Saudi Arabia. The study was designed as a cross-sectional investigation; sixty children diagnosed to have severe early childhood caries were selected and another thirty caries free children were selected as control. Children were selected according to certain criteria; healthy normal, diagnosed as severe early childhood caries and age range 36-71 months. A clinical examination was done to measure decayed, missing and filled index, salivary tests to measure bacterial counts, buffering capacity and salivary flow rate. There was a highly significant difference in streptococcus count (p = 0.02), lactobacillus count (p = 0.00), between both groups, but there was no significant difference in the saliva buffering capacity and salivary flow rate. Based on the sample of patient studied, it was concluded that Streptococcus mutans and lactobacilli counts are major risk factors. Furthermore, there was no statistically significant difference in the saliva buffering capacity and salivary flow rate between the two groups.

Effect of self-cured acrylic resin added with an inorganic antibacterial agent on Streptococcus mutans

In order to develop an self-cured acrylic resin having an antibacterial property, three types of commercially available inorganic antibacterial agents were added, at 1% each, to UNIFAST III to evaluate the antibacterial property. The antibacterial test evaluated the amount of Streptococcus mutans attached to UNIFAST III, the residual viable count of Streptococcus mutans cultured on UNIFAST III. And the color tone changes evaluated immediate and temporal color tone changes of UNIFAST III caused by the addition of antibacterial agents. As a result, compared to UNIFAST III without any added inorganic antibacterial agent, a significant decrease was observed in the attachment amount and the residual viable count of Streptococcus mutans. In addition, when adding NOVARON from among the added inorganic antibacterial agents, UNIFAST III exhibited little change in the temporal color tone. Thus, these results suggest that the addition of antibacterial agents to resins is effective first step toward developing self-cured acrylic resins having an antibacterial property.

Chlorhexidine varnishes effectively inhibit Porphyromonas gingivalis and Streptococcus mutans - An in vivo study

Background:Chlorhexidine varnish (Cervitec- Ivoclar Vivadent- Liechtenstein) is a sustained-release delivery system that can provide protection against white spots and gingivitis, which are common iatrogenic side effects of orthodontic treatment. Chlorhexidine in varnish form does not depend on patient compliance, does not stain teeth or alter taste sensation like the mouth rinse.Materials and Methods:A split-mouth technique was followed in the treatment of 30 patients selected by stringent selection criteria, evaluating a single application of the test varnish on two randomly allotted quadrants along with a placebo on the other two quadrants. Streptococcus mutans counts responsible for white spots and P. gingivalis count [using PCR test] responsible for gingivitis were done at the start of the study, and then 1 and 3 months later.Results:The chlorhexidine varnish reduced the Streptococci mutans count at the end of 1 month, and this reduction was statistically significant. At the end of 3 months, there was no difference in the S. mutans counts between the two groups. There was a statistically significant reduction in the P. gingivalis count at the end of both 1 and 3 months in comparison to the placebo group.Conclusion:Chlorhexidine varnishes are capable of reducing S. mutans and P. gingivalis and gingivitis, thus improving the overall oral health of the patient. The side effects of chlorhexidine mouth rinses are not seen with this varnish. An application schedule of at least once a month is recommended as the effectiveness is reduced comparatively at the end of 3 months.

DMFT index assessment and microbiological analysis of Streptococcus mutans in institutionalized patients with special needs

Aim: To assess the DMFT (D = decayed; M = missing; F = filled) index of institutionalized patients with mild and moderate physical and mental disabilities and to correlate it with the Streptococcus mutans (S. mutans) counts in the supragingival bacterial biofilm. Methods: Dental examination of 28 patients aged 15 to 25 years was conducted to determine the DMFT index (number of decayed, missing and filled teeth). Supragingival plaque samples were collected from the buccal surfaces of all teeth. The samples were inoculated in SB20 medium and incubated at 37 °C for 48 hours. Spearman's correlation test was applied (p = 0.05) to evaluate the correlation between the DMFT index and the amount of S. mutans. Results: The mean DMFT recorded was 7.68 and a large mean number of S. mutans colony-forming units (cfu > 106) was found. No statistically significant correlation was found between the DMFT index and the number of S. mutans. Conclusions: Under the conditions of this study, no correlation was found between the DMFT index and the number of S. mutans cfu in institutionalized patients with mental retardation and physical disabilities.

Xylitol and Erythritol Decrease Adherence of Polysaccharide-Producing Oral Streptococci

Xylitol consumption decreases counts of mutans streptococci. However, the mechanism behind this decrease is not well understood. We studied not only type strains and clinical isolates of mutans streptococci, but also other polysaccharide-forming oral streptococci. Growth inhibition and adherence of cells to a smooth glass surface-reflecting synthesis of water-insoluble polysaccharides were studied in the presence of 2% (0.13 mol/l) and 4% (0.26 mol/l) xylitol. The effect of xylitol was compared to a novel polyol sweetener, erythritol. Except for Streptococcus mutans 10449 and S. sobrinus OMZ 176, the glass surface adhesion of most polysaccharide-forming streptococci was reduced by the presence of both 4% xylitol and erythritol. For the S. mutans and S. sobrinus type strains, the growth inhibition with 4% xylitol and erythritol was 36-77% and for the clinical S. mutans isolates 13-73%. Of the other oral streptococci, only S. sanguinis was inhibited with 4% xylitol (45-55%). For both polyols, the magnitude of the growth inhibition observed was not associated with the magnitude of the decrease in adherence (xylitol: r = -0.18; erythritol: r = 0.49). In conclusion, both xylitol and erythritol can decrease polysaccharide-mediated cell adherence contributing to plaque accumulation through a mechanism not dependent on growth inhibition.