Caries-preventive effect of dentifrices containing various types and concentrations of fluorides and sugar alcohols

Antimicrobial Efficacy of Commercially Available Low-fluoride and Fluoride-free Dentifrices for Children

Aim and objective

The objective of this study was to evaluate and compare the antimicrobial efficacy of low-fluoride and fluoride-free dentifrices against Streptococcus mutans.

Materials and methods

The antimicrobial efficacy of four commercially available low-fluoride child formula dentifrices and four fluoride-free dentifrices against S. mutans was determined using the agar diffusion test. Fifty microliters of various dilutions (1:1, 1:2, 1:4) of each dentifrice were inoculated on the assigned plates under aseptic conditions. Saline was taken as negative control and 0.2% chlorhexidine was considered as a positive control. The plates were incubated at 37°C for 24 hours and the zone of inhibition around the wells was measured.

Results

All the tested low-fluoride dentifrices showed varying degrees of antimicrobial activity against S. mutans with F2 (Pediflor®) and F4 (Cheerio™) showing greater zones of inhibition when compared to F1 (Colgate®kids) and F3 (Kidodent). When the mean zones of inhibition produced by non-fluoridated dentifrices were compared with that of fluoridated dentifrices, no statistically significant difference was noted between NF1, NF3, NF4, and F2, F4. The antibacterial activity of F1 and F3 was significantly lower when compared to others. However, no antibacterial activity was noted with NF2.

Conclusion

Both low-fluoride and fluoride-free formulations tested in the study exhibited antimicrobial activity against S. mutans. In very young children where the risk of fluorosis is of concern, fluoride-free formulations can be considered as safe alternatives to fluoride formulations.

Clinical significance

Several dentifrices, both fluoride-free and low-fluoride formulations, are being aggressively marketed for young children. Though these toothpastes are being very commonly used by young parents for their infants and toddlers, there is very little published literature available on their antimicrobial activity and this study focuses on addressing this.

How to cite this article

Reddy D, Selvan A, Paul ST, et al. Antimicrobial Efficacy of Commercially Available Low-fluoride and Fluoride-free Dentifrices for Children. Int J Clin Pediatr Dent 2021;14(2):183–186.

Fluoride toothpastes of different concentrations for preventing dental caries

BACKGROUND

Caries (dental decay) is a disease of the hard tissues of the teeth caused by an imbalance, over time, in the interactions between cariogenic bacteria in dental plaque and fermentable carbohydrates (mainly sugars). Regular toothbrushing with fluoride toothpaste is the principal non-professional intervention to prevent caries, but the caries-preventive effect varies according to different concentrations of fluoride in toothpaste, with higher concentrations associated with increased caries control. Toothpastes with higher fluoride concentration increases the risk of fluorosis (enamel defects) in developing teeth. This is an update of the Cochrane Review first published in 2010.

OBJECTIVES

To determine and compare the effects of toothpastes of different fluoride concentrations (parts per million (ppm)) in preventing dental caries in children, adolescents, and adults.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 August 2018); the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 7) in the Cochrane Library (searched 15 August 2018); MEDLINE Ovid (1946 to 15 August 2018); and Embase Ovid (1980 to 15 August 2018). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials (15 August 2018). No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials that compared toothbrushing with fluoride toothpaste with toothbrushing with a non-fluoride toothpaste or toothpaste of a different fluoride concentration, with a follow-up period of at least 1 year. The primary outcome was caries increment measured by the change from baseline in the decayed, (missing), and filled surfaces or teeth index in all permanent or primary teeth (D(M)FS/T or d(m)fs/t).

DATA COLLECTION AND ANALYSIS

Two members of the review team, independently and in duplicate, undertook the selection of studies, data extraction, and risk of bias assessment. We graded the certainty of the evidence through discussion and consensus. The primary effect measure was the mean difference (MD) or standardised mean difference (SMD) caries increment. Where it was appropriate to pool data, we used random-effects pairwise or network meta-analysis.

MAIN RESULTS

We included 96 studies published between 1955 and 2014 in this updated review. Seven studies with 11,356 randomised participants (7047 evaluated) reported the effects of fluoride toothpaste up to 1500 ppm on the primary dentition; one study with 2500 randomised participants (2008 evaluated) reported the effects of 1450 ppm fluoride toothpaste on the primary and permanent dentition; 85 studies with 48,804 randomised participants (40,066 evaluated) reported the effects of toothpaste up to 2400 ppm on the immature permanent dentition; and three studies with 2675 randomised participants (2162 evaluated) reported the effects of up to 1100 ppm fluoride toothpaste on the mature permanent dentition. Follow-up in most studies was 36 months.In the primary dentition of young children, 1500 ppm fluoride toothpaste reduces caries increment when compared with non-fluoride toothpaste (MD -1.86 dfs, 95% confidence interval (CI) -2.51 to -1.21; 998 participants, one study, moderate-certainty evidence); the caries-preventive effects for the head-to-head comparison of 1055 ppm versus 550 ppm fluoride toothpaste are similar (MD -0.05, dmfs, 95% CI -0.38 to 0.28; 1958 participants, two studies, moderate-certainty evidence), but toothbrushing with 1450 ppm fluoride toothpaste slightly reduces decayed, missing, filled teeth (dmft) increment when compared with 440 ppm fluoride toothpaste (MD -0.34, dmft, 95%CI -0.59 to -0.09; 2362 participants, one study, moderate-certainty evidence). The certainty of the remaining evidence for this comparison was judged to be low.We included 81 studies in the network meta-analysis of D(M)FS increment in the permanent dentition of children and adolescents. The network included 21 different comparisons of seven fluoride concentrations. The certainty of the evidence was judged to be low with the following exceptions: there was high- and moderate-certainty evidence that 1000 to 1250 ppm or 1450 to 1500 ppm fluoride toothpaste reduces caries increments when compared with non-fluoride toothpaste (SMD -0.28, 95% CI -0.32 to -0.25, 55 studies; and SMD -0.36, 95% CI -0.43 to -0.29, four studies); there was moderate-certainty evidence that 1450 to 1500 ppm fluoride toothpaste slightly reduces caries increments when compared to 1000 to 1250 ppm (SMD -0.08, 95% CI -0.14 to -0.01, 10 studies); and moderate-certainty evidence that the caries increments are similar for 1700 to 2200 ppm and 2400 to 2800 ppm fluoride toothpaste when compared to 1450 to 1500 ppm (SMD 0.04, 95% CI -0.07 to 0.15, indirect evidence only; SMD -0.05, 95% CI -0.14 to 0.05, two studies).In the adult permanent dentition, 1000 or 1100 ppm fluoride toothpaste reduces DMFS increment when compared with non-fluoride toothpaste in adults of all ages (MD -0.53, 95% CI -1.02 to -0.04; 2162 participants, three studies, moderate-certainty evidence). The evidence for DMFT was low certainty.Only a minority of studies assessed adverse effects of toothpaste. When reported, effects such as soft tissue damage and tooth staining were minimal.

AUTHORS' CONCLUSIONS

This Cochrane Review supports the benefits of using fluoride toothpaste in preventing caries when compared to non-fluoride toothpaste. Evidence for the effects of different fluoride concentrations is more limited, but a dose-response effect was observed for D(M)FS in children and adolescents. For many comparisons of different concentrations the caries-preventive effects and our confidence in these effect estimates are uncertain and could be challenged by further research. The choice of fluoride toothpaste concentration for young children should be balanced against the risk of fluorosis.

Comparison of Antimicrobial Activity of Child Formula Dentifrices at different Concentrations: An in vitro Study

Aim

The aim of the present in vitro study is to evaluate and compare antimicrobial efficacy of commercially available child’s dental formulas in reduced concentrations containing different forms of fluoride against Streptococcus mutans activity.

Materials and methods

The selected dentifrices were prepared in dilutions of 1:1, 1:2, 1:4, 1:8, and 1:16 using sterile pyrogen-free distilled water. Various dilutions of the selected toothpaste slurries were incubated in the agar plate containing pure strains of S. mutans, and antimicrobial activity of each was assessed by measuring the diameter of zones of inhibition (in mm). Agar well plate diffusion method and minimum inhibitory concentration (MIC) determination were the methods used in this study. The inhibitory circle of each dentifrice was measured and MIC was achieved by considering the value of diameter of the circle.

Results

The results of the study showed that even at a lower concentration of fluoride, inhibition halos were obtained for all the formulations at different dilutions.

Conclusion

The kid’s formulations having lower fluoride concentration show antimicrobial activity even after dilutions. Thus, commercially, the fluoride concentrations can be further lowered down in the dentifrices, thereby reducing the risk associated with fluoride.

How to cite this article

Malhotra R, Singla S, Shashikiran ND. Comparison ofAntimicrobial Activity of Child Formula Dentifrices at different Concentrations: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):131-135.

In vitro antimicrobial evaluation of toothpastes with natural compounds

OBJECTIVES

This in vitro study evaluated the antimicrobial effects of commercial toothpastes containing natural compounds.

MATERIALS AND METHODS

The study groups were divided based on the natural compound present in the toothpaste composition: Sorbitol (I), tocopherol (II), mint (III), cinnamon/mint (IV), propolis/melaleuca (V), mint/açai (VI), mint/guarana (VII), propolis (VIII), negative control (IX), and the positive control (X). The antimicrobial properties of the toothpastes were tested using the disk diffusion method against oral pathogens: Streptococcus mutans, Pseudomonas aeruginosa, and Enterococcus faecalis. The resulting inhibition halos were measured in millimeters.

RESULTS

The data indicated that the bacteria responded differently to the toothpastes (P < 0.0001). The diameters of the inhibition halos against S. mutans were in decreasing order of efficacy: Propolis/melaleuca > mint/guarana > mint/açai > sorbitol > tocopherol > cinnamon/mint > propolis > mint (P < 0.001 vs. negative control). E. faecalis showed variable responses to the dentifrices in the following order of decreasing efficacy: Mint/guarana > propolis > sorbitol > mint/açai > tocopherol > cinnamon/mint > mint = propolis/melaleuca = negative control. The product with the highest antimicrobial activity was mint/guarana, which was significantly different than propolis/melaleuca, mint, cinnamon/mint, and tocopherol and negative control (P < 0.001). The statistical analysis indicated that propolis, sorbitol, and mint/açai did not show any differences compared to mint/guarana (P > 0.05) and positive control (P > 0.05). P. aeruginosa was resistant to all dental gels tested including positive control.

CONCLUSION

The toothpastes with natural compounds have therapeutic potential and need more detailed searches for the correct clinic therapeutic application. The results from this study revealed differences in the antimicrobial activities of commercial toothpastes with natural compounds.

Xylitol-containing products for preventing dental caries in children and adults

BACKGROUND

Dental caries is a highly prevalent chronic disease which affects the majority of people. It has been postulated that the consumption of xylitol could help to prevent caries. The evidence on the effects of xylitol products is not clear and therefore it is important to summarise the available evidence to determine its effectiveness and safety.

OBJECTIVES

To assess the effects of different xylitol-containing products for the prevention of dental caries in children and adults.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Oral Health Group Trials Register (to 14 August 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2014, Issue 7), MEDLINE via OVID (1946 to 14 August 2014), EMBASE via OVID (1980 to 14 August 2014), CINAHL via EBSCO (1980 to 14 August 2014), Web of Science Conference Proceedings (1990 to 14 August 2014), Proquest Dissertations and Theses (1861 to 14 August 2014). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials assessing the effects of xylitol products on dental caries in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the electronic searches, extracted data and assessed the risk of bias of the included studies. We attempted to contact study authors for missing data or clarification where feasible. For continuous outcomes, we used means and standard deviations to obtain the mean difference and 95% confidence interval (CI). We used the continuous data to calculate prevented fractions (PF) and 95% CIs to summarise the percentage reduction in caries. For dichotomous outcomes, we reported risk ratios (RR) and 95% CIs. As there were less than four studies included in the meta-analysis, we used a fixed-effect model. We planned to use a random-effects model in the event that there were four or more studies in a meta-analysis.

MAIN RESULTS

We included 10 studies that analysed a total of 5903 participants. One study was assessed as being at low risk of bias, two were assessed as being at unclear risk of bias, with the remaining seven being at high risk of bias.The main finding of the review was that, over 2.5 to 3 years of use, a fluoride toothpaste containing 10% xylitol may reduce caries by 13% when compared to a fluoride-only toothpaste (PF -0.13, 95% CI -0.18 to -0.08, 4216 children analysed, low-quality evidence).The remaining evidence on children, from small single studies with risk of bias issues and great uncertainty associated with the effect estimates, was insufficient to determine a benefit from xylitol products. One study reported that xylitol syrup (8 g per day) reduced caries by 58% (95% CI 33% to 83%, 94 infants analysed, low quality evidence) when compared to a low-dose xylitol syrup (2.67 g per day) consumed for 1 year.The following results had 95% CIs that were compatible with both a reduction and an increase in caries associated with xylitol: xylitol lozenges versus no treatment in children (very low quality body of evidence); xylitol sucking tablets versus no treatment in infants (very low quality body of evidence); xylitol tablets versus control (sorbitol) tablets in infants (very low quality body of evidence); xylitol wipes versus control wipes in infants (low quality body of evidence).There was only one study investigating the effects of xylitol lozenges, when compared to control lozenges, in adults (low quality body of evidence). The effect estimate had a 95% CI that was compatible with both a reduction and an increase in caries associated with xylitol.Four studies reported that there were no adverse effects from any of the interventions. Two studies reported similar rates of adverse effects between study arms. The remaining studies either mentioned adverse effects but did not report any usable data, or did not mention them at all. Adverse effects include sores in the mouth, cramps, bloating, constipation, flatulence, and loose stool or diarrhoea.

AUTHORS' CONCLUSIONS

We found some low quality evidence to suggest that fluoride toothpaste containing xylitol may be more effective than fluoride-only toothpaste for preventing caries in the permanent teeth of children, and that there are no associated adverse-effects from such toothpastes. The effect estimate should be interpreted with caution due to high risk of bias and the fact that it results from two studies that were carried out by the same authors in the same population. The remaining evidence we found is of low to very low quality and is insufficient to determine whether any other xylitol-containing products can prevent caries in infants, older children, or adults.

The effect of xylitol on dental caries and oral flora

Dental caries, the most chronic disease affecting mankind, has been in the limelight with regard to its prevention and treatment. Professional clinical management of caries has been very successful in cases of different severities of disease manifestations. However, tertiary management of this disease has been gaining attention, with numerous methods and agents emerging on a daily basis. Higher intake of nutritive sweeteners can result in higher energy intake and lower diet quality and thereby predispose an individual to conditions like obesity, cardiovascular disorders, and type 2 diabetes mellitus. Non-nutritive sweeteners have gained popularity as they are sweeter and are required in substantially lesser quantities. Xylitol, a five-carbon sugar polyol, has been found to be promising in reducing dental caries disease and also reversing the process of early caries. This paper throws light on the role and effects of various forms of xylitol on dental caries and oral hygiene status of an individual.

Effect of xylitol versus sorbitol: a quantitative systematic review of clinical trials

OBJECTIVES

This study aimed to appraise, within the context of tooth caries, the current clinical evidence and its risk for bias regarding the effects of xylitol in comparison with sorbitol.

METHODS

Databases were searched for clinical trials to 19 March 2011. Inclusion criteria required studies to: test a caries-related primary outcome; compare the effects of xylitol with those of sorbitol; describe a clinical trial with two or more arms, and utilise a prospective study design. Articles were excluded if they did not report computable data or did not follow up test and control groups in the same way. Individual dichotomous and continuous datasets were extracted from accepted articles. Selection and performance/detection bias were assessed. Sensitivity analysis was used to investigate attrition bias. Egger's regression and funnel plotting were used to investigate risk for publication bias.

RESULTS

Nine articles were identified. Of these, eight were accepted and one was excluded. Ten continuous and eight dichotomous datasets were extracted. Because of high clinical heterogeneity, no meta-analysis was performed. Most of the datasets favoured xylitol, but this was not consistent. The accepted trials may be limited by selection bias. Results of the sensitivity analysis indicate a high risk for attrition bias. The funnel plot and Egger's regression results suggest a low publication bias risk. External fluoride exposure and stimulated saliva flow may have confounded the measured anticariogenic effect of xylitol.

CONCLUSIONS

The evidence identified in support of xylitol over sorbitol is contradictory, is at high risk for selection and attrition bias and may be limited by confounder effects. Future high-quality randomised controlled trials are needed to show whether xylitol has a greater anticariogenic effect than sorbitol.

Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents

BACKGROUND

Caries (dental decay) is a disease of the hard tissues of the teeth caused by an imbalance, over time, in the interactions between cariogenic bacteria in dental plaque and fermentable carbohydrates (mainly sugars). The use of fluoride toothpaste is the primary intervention for the prevention of caries.

OBJECTIVES

To determine the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents, and to examine the potentially modifying effects of baseline caries level and supervised toothbrushing.

SEARCH STRATEGY

A search was undertaken on Cochrane Oral Health Group's Trials Register, CENTRAL, MEDLINE and several other databases. Reference lists of articles were also searched. Date of the most recent searches: 8 June 2009.

SELECTION CRITERIA

Randomised controlled trials and cluster-randomised controlled trials comparing fluoride toothpaste with placebo or fluoride toothpaste of a different concentration in children up to 16 years of age with a follow-up period of at least 1 year. The primary outcome was caries increment in the permanent or deciduous dentition as measured by the change in decayed, (missing), filled tooth surfaces (D(M)FS/d(m)fs) from baseline.

DATA COLLECTION AND ANALYSIS

Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were resolved by discussion and consensus or by a third party. The primary effect measure was the prevented fraction (PF), the caries increment of the control group minus the caries increment of the treatment group, expressed as a proportion of the caries increment in the control group. Where it was appropriate to pool data, network meta-analysis, network meta-regression or meta-analysis models were used. Potential sources of heterogeneity were specified a priori and examined through random-effects meta-regression analysis where appropriate.

MAIN RESULTS

75 studies were included, of which 71 studies comprising 79 trials contributed data to the network meta-analysis, network meta-regression or meta-analysis.For the 66 studies (74 trials) that contributed to the network meta-analysis of D(M)FS in the mixed or permanent dentition, the caries preventive effect of fluoride toothpaste increased significantly with higher fluoride concentrations (D(M)FS PF compared to placebo was 23% (95% credible interval (CrI) 19% to 27%) for 1000/1055/1100/1250 parts per million (ppm) concentrations rising to 36% (95% CrI 27% to 44%) for toothpastes with a concentration of 2400/2500/2800 ppm), but concentrations of 440/500/550 ppm and below showed no statistically significant effect when compared to placebo. There is some evidence of a dose response relationship in that the PF increased as the fluoride concentration increased from the baseline although this was not always statistically significant. The effect of fluoride toothpaste also increased with baseline level of D(M)FS and supervised brushing, though this did not reach statistical significance. Six studies assessed the effects of fluoride concentrations on the deciduous dentition with equivocal results dependent upon the fluoride concentrations compared and the outcome measure. Compliance with treatment regimen and unwanted effects was assessed in only a minority of studies. When reported, no differential compliance was observed and unwanted effects such as soft tissue damage and tooth staining were minimal.

AUTHORS' CONCLUSIONS

This review confirms the benefits of using fluoride toothpaste in preventing caries in children and adolescents when compared to placebo, but only significantly for fluoride concentrations of 1000 ppm and above. The relative caries preventive effects of fluoride toothpastes of different concentrations increase with higher fluoride concentration. The decision of what fluoride levels to use for children under 6 years should be balanced with the risk of fluorosis.

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.

Effect of Fluoride Varnish on Streptococcus mutans Count in Saliva of Caries Free Children Using Dentocult SM Strip Mutans Test: A Randomized Controlled Triple Blind Study

Aims: The aim of this study was to estimate the count of Streptococcus mutans in saliva of caries free children using Dentocult SM strip mutans and to evaluate the effect of fluoride varnish on the Streptococcus mutans count in saliva of these caries free children.

Methods and material: Thirty caries free children were selected for the study based on the information obtained from a questionnaire prepared. They were randomly assigned into the control group and the study group consisting of ten and twenty children respectively. Samples of saliva were collected using the saliva strips from the Dentocult SM kit and after incubation the presence of the Streptococcus mutans was evaluated using the manufacturers’ chart. The study group was subjected to Fluor Protector fluoride varnish application after 24 hours following which the samples were collected again.

Results: The average Streptococcus mutans count in primary dentition of caries free children was in the range of 10⁴ to 10⁵ colony forming units/ml. The average Streptococcus mutans count in primary dentition of caries free children after Fluor Protector fluoride varnish application was below 10⁴ colony forming units/ml.

Conclusion: Fluor Protector fluoride varnish application showed a statistically significant reduction in the Streptococcus mutans count in saliva of the caries free children in the study group.

Similarity of the effects of erythritol and xylitol on some risk factors of dental caries

Several sugar alcohols (polyols) have been promoted as potential sugar substitutes in caries limitation. However, differences in the effects of simple alditol-type sugar alcohol homologues on dental plaque have not been compared in clinical tests. The effects of 6-month use of erythritol (a sugar alcohol of the tetritol type), xylitol (a pentitol) and D-glucitol (sorbitol, a hexitol) were investigated in a cohort of 136 teenage subjects assigned to the respective polyol groups or to an untreated control group (n = 30-36 per group). The daily use of the polyols was 7.0 g in the form of chewable tablets, supplemented by twice-a-day use of a dentifrice containing those polyols. The use of erythritol and xylitol was associated with a statistically significant reduction (p < 0.001 in most cases) in the plaque and saliva levels of mutans streptococci. The amount of dental plaque was also significantly reduced in subjects receiving erythritol and xylitol. Such effects were not observed in other experimental groups. Chemical analyses showed D-glucitol to be a normal finding in dental plaque while xylitol was less consistently detected. Erythritol was detected in measurable amounts only in the plaque of subjects receiving this polyol. Erythritol and xylitol may exert similar effects on some risk factors of dental caries, although the biochemical mechanism of the effects may differ. These in vivo studies were supported by cultivation experiments in which xylitol, and especially erythritol, inhibited the growth of several strains of mutans streptococci.

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.

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 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.

Physiological approaches to the control of oral biofilms

Evidence that physiological strategies may be potential routes for oral biofilm control has come from (i) observations of the variations in the intra-oral distribution of members of the resident oral microflora, (ii) changes in plaque composition in health and disease, and (iii) data from laboratory model systems. Key physiological factors that were identified as significant in modulating the microflora included the local pH, redox potential (Eh), and nutrient availability. Increases in mutans streptococci and lactobacilli occur at sites with caries; growth of these species is selectively enhanced at low pH. In contrast, periodontal diseases are associated with plaque accumulation, followed by an inflammatory host response. The increases in Gram-negative, proteolytic, and obligately anaerobic bacteria reflect a low redox potential and a change in nutrient status due to the increased flow of gingival crevicular fluid (GCF). Consequently, physiological strategies for oral biofilm control should focus on reducing the frequency of low pH in plaque by (i) inhibiting acid production, (ii) using sugar substitutes, and (iii) promoting alkali generation from arginine or urea supplements. Similarly, strategies to make the pocket environment less favorable to periodonto-pathogens include (i) anti-inflammatory agents to reduce the flow of (and hence nutrient supply by) GCF, (ii) bacterial protease inhibitors, and (iii) redox agents to raise the Eh locally. Most laboratory and clinical findings support the concept of physiological control. However, some data suggest that the ordered structure and metabolically interactive organization of mature dental plaque could generate a community with a high level of homeostasis that is relatively resistant to deliberate external manipulation.

Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The committee screened several hundred articles, citing 518 published papers. Some are present quality in research, others provide clinical interest, and some are identified as misleading. New techniques in pulp physiology and pathology are reported. Laser use and techniques in prevention, restorative dentistry, and materials use are reported. Epidemiology of selected diseases and the results of various formulations for treatment are cited. Diagnosis of craniomandibular dysfunction is well represented as well as references to literature reviews and other sophisticated scientific investigation. Research on adhesives is presented in respect to bonding agents for dentin and enamel. Several clinical studies are included, along with customary laboratory reports on several materials.

Effects of xylitol and fluoride on the response to glucose pulses of Streptococcus mutans T8 growing in continuous culture

Streptococcus mutans T8 was grown glucose-limited at pH 7.0 in a chemostat and pulsed, under pH free-fall conditions, with glucose, xylitol or a mixture of the two. Experiments were conducted in the absence or continual presence of low levels (1 mmol.l-1) of fluoride. Culture filtrates of samples taken at frequent intervals were assayed for carbohydrate and fermentation end-products. Fluoride had little effect on the organism's response to glucose until the culture pH fell to ca. 5.0, at which point the rate of lactate production was reduced some 3-fold. Xylitol affected the response to glucose but its effect was most marked in the presence of fluoride. Under these conditions, the rate of lactate production was reduced at least 3-fold, the pH did not fall to 5.0 and only about 50% of the added glucose was consumed. This suggests that xylitol can augment the metabolic effects on S. mutans of low levels of fluoride.