Associations between salivary levels of Streptococcus mutans, Streptococcus sobrinus, lactobacilli, and caries experience in Kenyan adolescents

Investigation and comparison of the effects of two probiotic bacteria, and in reducing mutans streptococci levels in the saliva of children

Background

Probiotic organisms Lactobacillus reuteri UBLRU-87 and Bifidobacterium bifidum UBBB-55 were proven to be acting against the caries causing organisms.

Aims

This study aims to evaluate the influence of Lactobacillusreuteri, Bifidobacterium bifidum and their blend on Mutans streptococci count in the saliva of children, and also to appraise the sustainability of their action.

Materials and Methods

A randomized, double-blind and placebo-controlled study with 60 subjects (15 in each group) in 6-14 years of age group. The children consumed curd containing Bifidobacterium bifidum (UBBB 55, MTCC 5398) and Lactobacillus reuteri (UBLRu 87, MTCC 5403), and their blend once daily for 14 days. The control group received curd with no Probiotic in it. The saliva samples were collected just before the curd (T0) administration to establish baseline levels of mutans streptococci and after a day of the final consumption of the curd (T14). The follow-up samples at 21 days (T21) and 28 days (T28) after the baseline were also collected to know the sustainability of action probiotics on mutans streptococci if any.

Results

Statistically significant reduction of mutans streptococci is observed in the group administered with Lactobacillus reuteri and the effect lasted up to a minimum of 21 days. Mixed cultures are seemed to be not effective against the oral microorganisms.

Conclusions

The probiotic organism Lactobacillus reuteri in Indian curd is effective on salivary mutans streptococci, and the effect was sustained for some period after the administration.

Effectiveness of Fluoridation Depending on Periodicity in 6–10-year-old Children

Background

The cost-effectiveness of this study was achieved in the group that was treated every three months with periodic intervals, which had a reduction of caries with 62%. The relative effectiveness of our study is the application of fluoride treatment every 3 months compared with treatments done every 4 and 6 months, respectively.

Objective

To evaluate the reduction of caries disease depending on the time period of fluoride gel application. The sample was chosen randomly.

Main hypothesis

The frequency of fluoride gel application every 3 months has positive impacts on reducing dental caries.

Basic design

This is a cross-sectional study with a controlled sample for a period of 24 months. Durashield fluoride fluid (5% sodium fluoride) was used for the treatment of permanent dentition of the 6–10-year-old children.

Clinical setting

This study proves that fuoride application every 3 months significantly reduces caries morbidity.

Participants

Our study included 400 children, who were divided into 4 groups, 100 children in each group.

Intervention

The first group did not undergo any treatment and it is called the control group. The second group was under fluoride treatment every 4 months. The third group was treated with fluoride every 3 months, and the fourth group was treated every 6 months.

Results

The data collected from the control group showed that there is an increase in 24% of the caries incidence. In the group treated with fluoride every 4 months, caries incidence decreased to 30%. The group treated every 3 months with periodic intervals had a reduction of caries with 62%, while the group treated every 6 months had a reduction of 40%. Based on the analysis of variance (ANOVA) test, the fluoridation application every 3 months is significant for p = 0.000.

Conclusion

The best results were achieved in the treatment with fluoride in a 3-month periodic interval.

How to cite this article

Canga M, Malagnino VA et al. Effectiveness of Fluoridation Depending on Periodicity in 6–10-year-old Children. Int J Clin Pediatr Dent 2019;12(4):280–282.

Comparative evaluation of the effects of human breast milk and plain and probiotic-containing infant formulas on enamel mineral content in primary teeth: an in vitro study

AIM

This study quantitatively investigated the changes in enamel mineral content of primary teeth after immersion in human breast milk and plain and probiotic-containing infant formulas.

METHODS

Thirty-six sound primary anterior teeth were collected and assessed for mineral content (calcium and phosphorus content in wt%) using scanning electron microscope attached with energy-dispersive X-ray analyser (SEM-EDXA). In order to create a microbial-induced caries model, the enamel surfaces of the teeth were inoculated with mutans streptococci and then each tooth was randomly assigned to one of three groups: human breast milk, plain infant formula or probiotic-containing infant formula (n = 12) each. Teeth were then soaked in the designated type of milk, and the solutions were replenished every day for 1 week after which the mineral content was measured again using SEM-EDXA. Wilcoxon signed-rank test was used to study the changes by time within each group, and the significance level was set at P ≤ 0.05.

RESULTS

Treatment of enamel surface with breast milk has significantly increased mean Ca wt%, while no significant changes were detected in mean P wt%. On the other hand, when primary teeth were soaked in plain or probiotic-containing infant formulas, both mean values of both Ca and P wt% significantly decreased.

CONCLUSIONS

In conclusion, whereas breast milk might confer some protective effect against enamel demineralisation, infant formulas whether plain or supplemented with some probiotics might promote loss of minerals from enamel surface.

Salivary characteristics and dental caries experience in remote Indigenous children in Australia: a cross-sectional study

Background

While associations between salivary characteristics and dental caries have been well studied, we are not aware of this being assessed in a remote Indigenous child population, where lifestyles may be different from urban children. Our aim was to assess associations between caries experience and putative biomarkers in saliva, accounting for oral hygiene and dietary habits.

Methods

Children attending schools in an Indigenous community in remote north Queensland, Australia were invited to an oral examination by qualified and calibrated examiners. Salivary flow rate, pH, buffering capacity and loads of mutans streptococci (MS), lactobacilli (LB) and yeasts were determined. Also, data on tooth brushing frequency and soft drinks consumption were obtained via a questionnaire. Caries experience was recorded by the International Caries Detection and Assessment System (ICDAS-II), and quantified as decayed, missing and filled surfaces. Relationships between the salivary variables and the cumulative caries experience (dmfs+DMFS) in the deciduous and permanent dentitions were examined by multivariate analyses to control the effect of confounders.

Results

The mean cumulative decayed (DS + ds), missing (MS + ms) and filled (FS + fs) surfaces were 3.64 (SD: 4.97), 1.08 (4.38) and 0.79 (1.84) respectively. Higher salivary MS and LB counts, low tooth brushing frequency and daily soft drink consumption were significantly related to greater caries experience. Caries experience was about twice in those with ≥10^5 CFU/ml saliva counts of MS (mean = 6.33, SD: 8.40 vs 3.11, 5.77) and LB (7.03, 7.49 vs 4.41, 8.00). In the fully-adjusted multivariate model, caries experience in those with higher counts of MS and LB were 51 and 52% more than those with lower counts.

Conclusions

As with studies in other populations, childhood salivary counts of MS and LB were significantly associated with greater caries experience in this remote Indigenous community. To address the serious burden of oral disease, we are researching ways to promote a healthy oral environment by encouraging good dietary habits, and emphasising the importance of daily tooth brushing with a fluoridated toothpaste. Our ongoing longitudinal studies will indicate the success of measures employed to reduce the counts of bacteria closely associated with cariogenesis and their impact on caries increment.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), No: ACTRN12615000693527; date of registration: 3rd July 2015.

Distribution of Streptococcus mutans and Streptococcus sobrinus in Dental Plaque of Indian Pre-School Children Using PCR and SB-20M Agar Medium

INTRODUCTION

Dental caries is one of the most common infectious diseases affecting the oral cavity. Among the oral bacteria, mutans streptococci have been implicated as major cariogenic bacteria as they can produce high levels of dental caries causing substances such as lactic acid and extracellular polysaccharides.

AIM

The aim of the study was to detect the presence of Streptococcus mutans and Streptococcus sobrinus in dental plaque by using Polymerase Chain Reaction (PCR) method, quantification of these micro-organisms using Modified Sucrose-Bacitracin (SB-20M) agar medium and to correlate their presence in Caries Active (CA) and Caries Free (CF) pre-school children.

MATERIALS AND METHODS

Sixty-eight pre-school children, in the age group of 3-5 years were divided equally into 34 CA and 34 CF children. Dental plaque samples were obtained for detection of these microorganisms by PCR method and quantification was done using SB-20M culture medium. The data was analyzed using statistical software SPSS version 16. For statistical analysis, the frequencies and means of Colony Forming Units (CFU) were used with CI = 95%. For bivariate analysis, Fisher exact test was used at 5% level of significance. The comparison of mean of number of CFU of S. mutans and S. sobrinus was made by Mann Whitney U test and Spearman's Rho test at 1% level of significance was used for correlation between dmft and CFU in CA group.

RESULTS

The results showed that S. sobrinus was significantly higher in CA group as compared to CF group whereas S. mutans showed no significant difference. On quantification of these micro-organisms, S. sobrinus was present in significantly higher numbers in CA group as compared to CF group. On correlating the CFU/ml of the micro-organisms with the dmft index, both the micro-organisms showed a positive correlation.

CONCLUSION

We conclude that S. mutans and S. sobrinus were detected in higher numbers in CA children as compared to CF children. PCR is a sensitive, specific, rapid and an effective method for the detection of oral microorganisms.

Streptococcus mutans and Streptococcus sobrinus colonization and caries experience in 3- and 5-year-old Thai children

OBJECTIVES

The aim of this study was to examine the colonization of Streptococcus mutans and Streptococcus sobrinus in supra-gingival plaque samples and to determine their correlation with the prevalence of early childhood caries (ECC) in Thai children.

MATERIALS AND METHODS

A total of 344 Thai children, ages 3 and 5 years, were invited to participate in this study. Caries status of the children was examined. Supra-gingival plaque samples were collected. Quantitative real-time PCR was performed to evaluate DNA levels of S. mutans and S. sobrinus.

RESULTS

Eighty-five percent of the children were colonized by S. mutans and 50.9% of them were colonized by S. sobrinus. The prevalence of ECC was 43.8% and 56.2% among 3- and 5-year-old children, respectively, and was significantly associated with the presence of S. mutans and S. sobrinus. The severity of ECC was significantly correlated with increased DNA levels of the two bacteria. Children who were positive for S. mutans and S. sobrinus (Sm+/Sb+) were 8 times or 44 times more likely to experience ECC than children who were Sm-/Sb + or were Sm-/Sb-.

CONCLUSIONS

The study evidence further suggest that children colonized by both S. mutans and S. sobrinus are at the higher risk for ECC.

CLINICAL RELEVANCE

Molecular-based qPCR can be used to detect and quantify S. mutans and S. sobrinus colonization for epidemiological and clinical studies for ECC risk assessment.

Effect of oil gum massage therapy on common pathogenic oral microorganisms - A randomized controlled trial

Objectives:

(i) To assess reduction in Streptococcus mutans and Lactobacillus species count in saliva sample after ten minutes of oil gum massage therapy (massage of gingival tissues) per day for three weeks with sesame oil, olive oil, and coconut oil in three different groups of subjects. (ii) To compare the efficacy between three different oils and the “gold standard” chlorhexidine gel. (iii) To assess reduction in gingival scores and plaque scores of study subjects.

Materials and Methods:

Study design – Single center, parallel design, and triple blind randomized clinical study with four treatment groups. Participants: 32 of the 40 study subjects working as housekeeping personnel at Kasturba Hospital, Manipal; aged 18-55 years completed the three-week study period. Interventions: Subjects were randomly assigned to massage their gingiva everyday for three weeks with sesame oil, olive oil, coconut oil (tests), and Chlorhexidine gel (control). Oral health status and paraffin stimulated saliva samples were obtained at baseline and after three weeks of oil gum massage therapy. Outcome measures: Microbial culture, plaque index, and gingival index. Statistical analysis: Paired t test and Kruskal Wallis test.

Results:

There was a significant reduction in mean Streptococcus mutans count, Lactobacillus count, plaque scores, and gingival scores in all four groups after the study. However, there was no significant difference found in percentage reduction of these variables between the four groups.

Conclusion:

These oils can be used as valuable preventive agents in maintaining and improving oral health in low socioeconomic status population. However, it is recommended that further research should be conducted in other populations with a larger sample and longer duration of follow-up period.

Correlation between the salivary Streptococcus mutans levels and dental caries experience in adult population of Chandigarh, India

Objectives:

To determine the level of Streptococcus mutans (S. mutans) in adults of Chandigarh and to correlate the dental caries in these individuals with their S. mutans titers.

Materials and Methods:

Salivary levels of Streptococcus mutans, using Dentocult SM commercial kits were estimated in 200, 25-35 year old adults (males and females). Streptococcus mutans were detected in 87% of the study sample. Score 2, representing 10⁵-10⁶ CFU/ml (Colony Forming Unit) of saliva was found to be most prevalent, i.e. in 80 of 200 adults, followed by score 1, depicting S mutans with <10⁵ CFU/ml, in 56 of 200 adults and score 3, with bacterial titer >10⁶ CFU/ml in 38 of 200 adults.

Results:

Dental caries, recorded using Møller's index, was found to be maximum in individuals with score 3, followed by score 2,1 and 0, thereby showing a positive correlation of dental caries with increasing titers of S. mutans. This correlation was statistically highly significant in males with figures as 8.73 decayed surfaces at score 2 rising to 17.38 at score 3. The mean of DMFT was higher among females than in the males in the present study.

Conclusion:

The split up data in males and females, showed a positive association between caries experience and salivary S. mutans scores. The results of the study will serve as a baseline data for future planning of preventive programs in adults.

Caries-risk profile variations after short-term use of 5000 ppm fluoride toothpaste

OBJECTIVE

To assess the caries risk following 6 weeks' use of 5000 ppm F toothpaste using 'Cariogram' software.

MATERIALS AND METHODS

A total of 34 participants, 17 mothers and their teenage children, were enrolled in a 6-week clinical trial in which they were given 5000 ppm F toothpaste. They were followed consecutively for 6 weeks with visits that were 2 weeks apart (four in total). A clinical examination was done at baseline and salivary chair-side tests to record the buffer capacity and mutans streptococci (MS) and lactobacilli (LB) counts were performed at each visit. Based on these data, seven caries-related variables were collected and inserted into the Cariogram software to calculate the actual chance of avoiding caries.

RESULTS

The use of 5000 ppm F toothpaste resulted in a statistically significant modification of the caries-risk profile, increasing the actual chance of avoiding caries in the future among the mothers and teenagers at each visit following baseline (p < 0.01). The changes essentially related to the salivary parameters (buffer capacity, MS and LB counts). A statistically significant linear trend was observed for MS counts (p < 0.01) and the number of subjects with a salivary concentration of MS < 10(3) increased at each visit. The same trend was also observed for LB and buffer capacity scores (p = 0.04 and p = 0.03, respectively).

CONCLUSIONS

The short-term use of 5000 ppm F toothpaste is able to reduce the caries risk, which can be clearly demonstrated using 'Cariogram' software.

Systemic consumption of probiotic curd and use of probiotic toothpaste to reduce Streptococcus mutans in plaque around orthodontic brackets

INTRODUCTION

The objectives of the study were to evaluate and compare the effects of the systemic consumption of probiotic curd and the topical application of probiotic toothpaste on the Streptococcus mutans levels in the plaque of orthodontic patients.

METHODS

The study consisted of 60 orthodontic patients divided into 3 groups of 20 each. Group 1 was the control group. The patients in group 2 were given probiotic curd, and those in group 3 were asked to brush twice daily with probiotic toothpaste (GD toothpaste; Dental Asia Manufacturing, Shah Alam, Selangor, Malaysia). Samples were collected at 2 times: before the study began and after 30 days. Plaque specimens were collected from the labial surfaces immediately surrounding the orthodontic brackets of the maxillary lateral incisors using a 4-pass technique. The presence of S mutans was evaluated using real-time polymerase chain reaction. Statistical analysis was performed, and comparisons were made using a 2-tailed chi-square test for categorical data (P <0.05).

RESULTS

At the end of the study, there were reductions in S mutans concentration in groups 2 and 3 that were statistically significant compared with group 1, but there was no statistically significant difference between groups 2 and 3.

CONCLUSIONS

The consumption of probiotic curd and the use of probiotic toothpaste cause a significant decrease in the S mutans levels in the plaque around brackets in orthodontic patients. Although the probiotic toothpaste was more effective than systemic consumption, this was not statistically significant.

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.

An assessment of the cariogenicity of commonly used infant milk formulae using microbiological and biochemical methods

Dental caries is an important dental public health problem and is the most prevalent oral disease among children in the world. The present study was undertaken to evaluate and comparatively assess the change in plaque and salivary pH after ingestion of various commercially available infant milk formulae, and also to evaluate and comparatively assess plaque and salivary samples for change in colony-forming units of Streptococcus mutans caused due to their ingestion. 36 children in the age group of 1-2 years were fed with infant milk formulae three times a day for 21 days and results quantified. The present study revealed a highly significant increase in the levels of colony-forming units of Streptococcus mutans in both the plaque and salivary samples when assessed at baseline and after a period of 21 days, with the t value being 11.92 for the plaque samples and 11.66 for the salivary samples. It was also observed that all the test samples produced significantly lower plaque pH values than pre-feed pH. Based upon this study, further evaluation of the cariogenicity of infant milk formulae is recommended.

Caries risk profiles in Sardinian schoolchildren using Cariogram

OBJECTIVE

The aim of our study was to assess the caries risk profile in a group of Sardinian schoolchildren and to compare the outcome with their history of caries.

MATERIAL AND METHODS

Using the computer-based program "Cariogram", 957 subjects aged 7, 8, and 9 years were enrolled in this cross-sectional study. The children were examined to evaluate dmfs/DMFS and gingival conditions. Data on dietary and oral hygiene habits were collected and saliva was analyzed, including levels of mutans streptococci (MS) and lactobacilli (Lb). Based on the Cariogram profiles, the children were divided into five risk groups in accordance with "chance of avoiding caries".

RESULTS

Almost 50% of the children had a low caries risk, while more than a quarter had less than 40% "chance of avoiding caries". A significant linear trend between the five Cariogram categories and dmfs/DMFS was observed in the three age groups (p<0.001).

CONCLUSIONS

The Cariogram risk profile showed strong correlations to the caries experience of Sardinian schoolchildren and that efforts to reduce caries risk are necessary.

A lacticin 3147 enriched food ingredient reduces Streptococcus mutans isolated from the human oral cavity in saliva

AIMS

To isolate and characterise Streptococcus mutans from Irish saliva samples and to assess their sensitivity to a food-grade preparation of the lantibiotic, lacticin 3147, produced by Lactococcus lactis DPC3147.

METHODS AND RESULTS

Saliva samples collected from children with varying oral health status were screened on Mitis Salivarius agar for the presence of pathogenic streptococci. Following selective plating, 16S rDNA sequencing and Pulsed Field Gel Electrophoresis (PFGE), 15 distinct strains of Strep. mutans were identified. These were grouped according to their relative sensitivity to lacticin 3147 which ranged from 0.78 to 6.25%; relative to a sensitive indicator strain, Lactococcus lactis ssp. lactis HP. Inhibition of indicator Strep. mutans strains from sensitive, intermediate and tolerant groupings were assessed in microtitre plate assays with increasing concentrations of lacticin 3147. The concentration of lacticin 3147 required to give 50% growth inhibition correlated with their relative sensitivities (as assayed by well diffusion methodology) and ranged from 1280 to 5120 AU ml(-1). Concentrated preparations of lacticin 3147 caused a rapid killing of Strep. mutans strains in broth. Moreover, in human saliva deliberately spiked with Strep. mutans, the pathogen was eliminated (initial inoculum of 10(5)) in the presence of 40,000 AU ml(-1) of lacticin 3147. Furthermore, a food-grade lacticin 3147 spray dried powder ingredient was assessed for the inhibition of Strep. mutans in human saliva, spiked with a strain of intermediate sensitivity, resulting in up to a 4-log reduction in counts after 20 min.

CONCLUSION

A food grade preparation of lacticin 3147 was effective in the inhibition of oral Strep. mutans.

SIGNIFICANCE AND IMPACT OF THE STUDY

The inhibition of oral streptococci by food grade preparations of lacticin 3147 may offer novel opportunities for the development of lacticin 3147 as an anti-cariogenic agent particularly in the area of functional foods for the improvement of oral health.

A novel selective medium for isolation of Streptococcus mutans

The aim of this study was to improve the selective medium of Streptococcus mutans. A new selective medium, designated MS-MUTV, was prepared by adding 10 mg/l valinomycin to the MS-MUT medium previously described. The average recovery of S. mutans was 72.1%, and the growth of S. sobrinus and S. anginousus group was inhibited on MS-MUTV, but allowed on MS-MUT. One hundred and thirty-nine human saliva samples were examined and counted for S. mutans and non-S. mutans colonies. The recovery of S. mutans on MS-MUTV was similar to that on MS-MUT. Eighty-two and 7.9 percent of the saliva samples obtained S. mutans pure cultures, with no bacterial growth on MS-MUTV, respectively. The remaining 10.1% were contaminated with non-S. mutans, with low-level CFU. MS-MUTV is useful for the isolation of S. mutans alone from clinical samples in routine examinations.

Typing of Mutans Streptococci by Arbitrarily Primed PCR in Patients Undergoing Orthodontic Treatment

The aim of this study was to clarify the genotypic stability of mutans streptococci (MS) longitudinally during orthodontic treatment. Plaque samples were obtained from the supragingival smooth surface of the upper right teeth at four stages: prior to and after 1, 3 and 6 months of orthodontic treatment. Levels of total viable count, total streptococci and MS in dental plaque of 17 patients were recorded. Streptococci isolated from dental plaque samples were identified as MS on the basis of their morphological and biochemical properties. DNA was prepared from 713 strains of MS and the strains were then identified with polymerase chain reaction (PCR) again. Arbitrarily primed PCR (AP-PCR) fingerprinting was applied in determining the genotypes of MS. The results indicated that levels of total viable count, total streptococci and MS increased significantly after the fixed appliances were bonded. A maximum of 3 different genotypes were found in an individual. All the genotypes were found again after the application of the fixed appliances in 17 patients. A new AP-PCR typing pattern was found after the application of fixed appliances for 1 month in patient 1. That strain was not detected either prior to or after 3, or 6 months of treatment. The result indicated that the MS clones were very stable during orthodontic treatment.

Restoration-related salivary Streptococcus mutans level: a dental caries risk factor?

OBJECTIVES

The salivary level of Streptococcus mutans related to filled teeth was compared with the levels related to decayed and sound teeth, in order to establish whether the presence of restorations may increase the risk of infection of other teeth by Streptococcus mutans.

METHODS

The sound, decayed and filled teeth were recorded in 809, 6-7-year-old school-children. Salivary Streptococcus mutans detection (i.e. more than 1 x 10(4) CFU/ml) and counts were evaluated. Streptococcus mutans log count means and prevalence values of subjects with only sound teeth (group 1), with filled, without decayed teeth (group 2), with decayed, without filled teeth (group 3), were calculated and compared using the Student's t-test and the chi-square test. The effect of filled, decayed and sound teeth on Streptococcus mutans level was also evaluated using logistic regression.

RESULTS

Log count means and prevalence values of group 2 subjects were significantly lower than values of group 3 subjects (means, 0.92 vs 1.66: prevalence, 73.17% vs 94.63%) and statistically not-different from values of group 1 subjects (mean. 0.75: prevalence, 70.06%). The logistic regression analysis showed that the factors significantly increasing the risk of Streptococcus mutans being detected in saliva were only primary and/or permanent decayed teeth. The risk of Streptococcus mutans being detected in saliva was not affected by filled teeth more than sound teeth.

CONCLUSIONS

In the present study population, the salivary Streptococcus mutans level attributable to filled teeth was low; this suggests that treatment of a carious lesion would cause a lowering of Streptococcus mutans concentration to the same levels as those shown by healthy subjects, thus reducing the risk of infection to other teeth.

Concepts of dental caries and their consequences for understanding the disease

The way in which we conceptually consider dental caries determines our choice of preventive and treatment strategy. In this paper the definition of dental caries is discussed and the related problems concerning causality are addressed. Dental caries reflects symptoms of ongoing and past disease--not the disease itself. As such, it is important to record early stages of signs of the disease, i.e. non-cavitated stages of lesion development. The dynamic nature of the processes leading to net loss of mineral (hence a lesion) is emphasized, and appreciating that caries is ubiquitous in populations around the world and initiation and progression of lesions continues lifelong leads to the logical conclusion that we can control dental caries through a variety of measures--but not truly prevent the disease. We can prevent cavities by controlling the patho-physiological events which may result in a net loss of mineral. The relative role of dental plaque in caries control is discussed in relation to the role of the many determinants which influence the likelihood for lesion development. It is concluded that several paradigms about the nature of dental caries should be reconsidered to provide the most cost-effective dental services.

Dental caries in relation to diet, saliva and cariogenic microorganisms in Tanzanians of selected age groups

The relationship between diet and dental caries in a Tanzanian population was studied. Mutans streptococci, lactobacilli, yeasts, salivary flow rate as well as buffer effect were also analyzed. A random sample of 12-, 35-44- and 65- to 74- year olds was drawn from Msongola (rural) and Ukombozi (urban), Dar-es-Salaam. The mean of two 24-h recalls was used for the assessment of food intake. The percentage of those with at least one carious tooth ranged from 30% in the 12-year-olds to 80% in the oldest age group. The mean number of decayed teeth (DT) increased significantly with age (P = 0.000) but was not significantly associated with the area of residence. DT increased significantly (P = 0.048) with the number of snacks per day and was also associated with dietary sucrose (P = 0.025), total carbohydrates (P = 0.002) and fiber (P = 0.002). Among salivary variables lactobacilli (P = 0.000) correlated positively with DT. Our study did not reveal any strong association between total energy intake and dental caries in rural or urban populations in Tanzania but snacking and sucrose intake were significantly associated with caries, in particular in the urban area.

Cariogenicity depends more on diet than the prevailing mutans streptococcal species

This review aims to compare the occurrence and distribution of mutans streptococci in Africa, Europe, and North America and in addition will try to offer explanations for existing relationships among salivary mutans streptococci counts, dietary patterns, and dental caries. The literature reveals that salivary mutans streptococci counts in child populations of the three continents are comparable. The distribution of mutans streptococci species, with a predominance of S. mutans followed by S. sobrinus, and the virtual absence of other mutans streptococci species are also comparable. Although it is widely believed that diet has an important effect on mutans streptococci counts, this review provides evidence that this does not hold true when variations in dietary patterns are moderate, as they normally are in real-life situations. Since the diets of the child populations in the three continents vary moderately, a strong dietary-induced effect on salivary mutans streptococci counts cannot be expected. The observed analogous salivary mutans streptococci counts in these child populations are thus 'not surprising' but are in accordance with the conceptual expectation. The differences in caries experience in children of the three continents cannot be explained by the prevailing mutans streptococci species but instead should be attributed to differences in the cariogenicity of the various diets. The fact that the cariogenicity of the diet determines the development of dental caries while hardly affecting the mutans streptococci counts explains the limited value of the latter as an indicator of dental caries. The reviewed literature shows that mutans streptococci are ubiquitous in children aged 7 years and older in Africa, Europe, and North America. Mutans streptococci should therefore be considered as belonging to the indigenous microflora of the human mouth.

Oral health in adolescents from a small French town

In France, caries are more prevalent in rural areas than in large cities. This study analyzed the relationship between number of oral health indices and some known risk factors (toothbrushing, sugar consumption, saliva components) and sociodemographic factors in adolescents from a small town. The sample included 112 children aged 12-14 in the north-east of France. School marks was found to be better linked with dental caries indices than the socio-occupational category of parents: gingival index (GI), DMFS, DMFT and caries severity (CS) significantly increased with decreasing school marks; oral plaque was related to socio-occupational of parents. The analysis using the regression method showed that the variance explained by the various factors studied was modest (between 23 and 30%) for GI, initial caries sites (IS), DS, DMFS, DMFT and CS, and was small for plaque (5%) and calculus (3%). This would be due in part to the wide dispersion of these indices. The sex had a non-significant regression coefficient for all oral health indices investigated. For GI, only mutans streptococci (MS) and plaque had a significant regression coefficient. Calculus was explained by any factor considered. Only MS had a significant part in plaque. IS was explained by MS, toothbrushing and age. For DS, only toothbrushing, MS and sweet drinks during meals had a significant part. DMFS and DMFT were explained only by MS and age. CS was explained by MS, age, salivary buffer pH, salivary flow rate, and toothbrushing.

Salivary microflora and caries experience in 5-year-old children from two ethnic groups

The purposes of the study were threefold: to compare salivary levels of mutans streptococci and Lactobacillus in 140 5-year-old children from two ethnic groups, to correlate caries experience of each group with bacterial counts, and to determine levels of infectivity which could indicate high caries activity in young children. Pakistani-Muslim and white Caucasian children were paired, matched for age, gender and caries experience. There were no significant differences in mutans streptococci or Lactobacillus levels between the two ethnic groups. However, strong correlations were found between caries experience and levels of both mutans streptococci and Lactobacillus in each ethnic group. Furthermore, mutans streptococci and Lactobacillus levels correlated strongly with one another. For detection of high caries activity, the optimum screening levels of bacteria were > 10(5) cfu/ml for mutans streptococci (sensitivity 78% and specificity 86%) and > 10(4) cfu/ml for Lactobacillus (sensitivity 82% and specificity 89%).

Isolation frequency and serotype distribution of mutans streptococci and Actinobacillus actinomycetemcomitans, and clinical periodontal status in Finnish and Vietnamese children

The isolation frequency and serotype distribution of mutans streptococci and A. actinomycetemcomitans (A.a.) were investigated in a group of Finnish (n = 16) and Vietnamese (n = 16) children, matched by sex, age, and caries status. In the Vietnamese children, the isolation frequencies were higher than in the Finnish children: 100%/62% for mutans streptococci and 78%/13% for A.a. Isolates (n = 3-8) from plaque and saliva were serotyped by immunodiffusion technique using serotype-specific antisera against serotypes c, e, f, d, and g for mutans streptococci and a, b, c, d, and e for A.a. The distribution of mutans streptococci serotypes in Finnish/Vietnamese children was: c 100%/50%; e 10%/31%; d 0%/56%; g 20%/38%. The frequency of plural serotypes was 30%/75%, respectively. In the Vietnamese group the serotype distribution of A.a. was: a 36%, b 27%, and c 63%; 45% of children carried two serotypes. One Finnish child harbored serotype a and one serotype b. The mean percentage of bleeding gingival sites was 7.4 in the Finnish and 15.1 in the Vietnamese group. Calculus and clinically deepened gingival pockets were more frequent findings in the Vietnamese children. The results indicate considerable differences in bacteriologic status and in clinical periodontal status between these Finnish and Vietnamese children.

The use of a concentrated oral rinse culture technique to sample oral candida and lactobacilli in children, and the relationship between candida and lactobacilli levels and dental caries experience: a pilot study

The purpose of this study was to test the suitability of a concentrated rinse culture technique, previously applied to adults, as a method for sampling the oral cavity of children on a community basis. The technique was used to assess the levels of oral candida and lactobacilli in the mouths of a group of 32 14- to 15-year-old children and to relate this to their past caries experience. Caries experience was assessed by means of a DMFS count. Each subject rinsed with 10 ml of buffered saline for 1 minute for microbial sampling. The oral rinse was concentrated by centrifugation and cultured on to selective media for candida and lactobacilli. The rinse technique proved simple and effective as a means of sampling the oral flora in children. The level of candida was more easily assessed and appeared to be a more useful indicator of microbial risk factors in caries than the lactobacilli count.

Dental caries and its determinants among recent immigrants from rural Ethiopia

Adults (35-45 yr old) and children (5 and 12 yr old) recently arrived in Israel from rural areas in Ethiopia were examined. Caries levels were low: e.g. DMFT = 0.31 among 12-yr-olds, and 1.27 amongst adults. The 5-yr-olds were 86.8% caries-free, while 12-yr-olds were 81.8% and adults 54% caries-free respectively. According to interview data, the diet in Ethiopia had been based on local agricultural products and was almost sugar-free. The mean total count of salivary bacteria, as determined on blood agar, was 3.4 x 10(8); mean count of Streptococcus viridans, on mitis salivarius, was 6.7 x 10(7); and mean count of S. mutans, as determined on mitis salivarius with bacitracin, was 1.7 x 10(7). These levels were all high and were not significantly different from a control group of 20 Israelis. The mean number of lactobacilli, on Rogosa agar, was 2.75 x 10(4), which was significantly higher than among the controls (3.6 x 10(3). Salivary pH levels were generally similar between the Ethiopian group and the controls. Salivary flow was significantly higher for the Ethiopians (1.93 ml/min) than for controls (1.16 ml/min). Low levels of caries in this population can be attributed to an almost sugar-free diet and high salivary flow, but not to the composition of oral microflora.

Latex agglutination test for detection of mutans streptococci in relation to dental caries in children

A simple and rapid system based on a latex agglutination (LA) reaction was devised for the detection of mutans streptococci in dental plaque. Latex particles were sensitized with antibodies against whole cells of Streptococcus mutans strains MT8148 (serotype c), MT703R (e) and OMZ175 (f) and Strep. sobrinus strains B13 (d) and 6715 (g). These sensitized particles were agglutinated within a few minutes after addition of 1.0-10 ng serotype-specific antigen from the homologous organisms or the nitrous acid extract of whole cells at 10(5)-10(6) c.f.u. The LA test specifically differentiated not only mutans streptococci from the other oral streptococci but also Strep. sobrinus from Strep. mutans. The LA test was also applicable to extracts of plaque from 206 human subjects who harboured mutans streptococci. In clinical trials, the outcome of the LA test correlated significantly with the number of mutans streptococci found in plaque (p less than 0.0001), which was quantified by the selective cultivation of mutans streptococci. Furthermore, the LA test discriminated between Strep. mutans and Strep. sobrinus from human dental plaque. The sensitivity and the specificity of the LA test for detection of mutans streptococci were 78.9 and 100%. The degree of reactivity in the LA test correlated significantly with the number of decayed tooth surfaces (p less than 0.0001) and decayed and filled tooth surfaces (p less than 0.0001). These results suggest that the LA test could be useful clinically for the detection of mutans streptococci in dental plaque as well as serving as a caries-activity test.

Sequence and structural analysis of surface protein antigen I/II (SpaA) of Streptococcus sobrinus

Streptococcal antigen I/II or the surface protein antigen A (SpaA) of Streptococcus sobrinus is an adhesin which mediates binding of the organism to tooth surfaces. The complete sequence of the gene which encodes SpaA has been determined. The gene consists of 4,584 bp and encodes a protein of 1,528 amino acid residues. The deduced amino acid sequence shows extensive homology with those of the cell surface adhesins from Streptococcus mutans serotypes c and f and from Streptococcus sanguis. Structural analysis of the N-terminal region (residues 50 to 550), which is rich in alanine and includes four tandem repeats of an 82-residue sequence, suggests that it adopts an alpha-helical coiled-coil conformation. Cell surface hydrophobicity may be associated with this region. The C-terminal region is more conserved and includes two tandem repeats of a 39-residue proline-rich sequence. A further proline-rich sequence in this region is predicted to span the cell wall. Although a hydrophobic sequence is present in the C-terminal region, it appears to be too short to span the cell membrane. Anchoring of SpaA in the cell membrane may therefore require some form of posttranslational modification or association with another membrane protein.

Associations of microbiological factors and plaque index with caries prevalence and water fluoridation status

Plaque indices, numbers of mutans streptococci, lactobacilli and total viable flora in plaque and saliva were assessed as part of a large-scale cross-sectional study designed to determine the factors that are associated with high caries activity in children. Subjects, 12 to 15 years old, residing in areas where the water supplies were either fluoridated (n = 140) or fluoride-deficient (n = 173) were studied. Mutans streptococci and lactobacilli numbers in saliva were positively correlated with plaque index. Plaque indices were significantly higher in the high-caries group than in the zero-caries group of the fluoride-deficient community. In the fluoridated community, there was no difference in the plaque index between the zero- or high-caries groups. In each community, pooled dental plaque and saliva harbored fewer mutans streptococci and lactobacilli in the zero-caries than the high-caries group. Greater numbers of mutans streptococci were found in the dental plaque and saliva of the zero-caries subjects in the fluoridated community than in the fluoride-deficient community, suggesting that a greater caries challenge can coexist with zero-caries status in the fluoridated community.

Dental caries in developing countries in relation to the appropriate use of fluoride

Although it is widely believed that caries prevalence in developing countries is increasing rapidly, a review of studies from Africa and China provides equivocal evidence. Data from child and adult populations indicate that the disease is almost ubiquitous but with a slow rate of progression. Theoretically, administration of fluoride in such populations should result in reducing caries progression rates, but too little is known about the magnitude of the effect, and therefore about the cost-effectiveness of different methods of fluoride administration. The lack of a developed infrastructure and of trained personnel in many developing countries limits the applicability of many strategies. Methods of fluoride administration that minimize systemic exposure are to be recommended where affordable or practical. In the light of economic constraints and slow caries lesion progression rates, however, improvements in oral hygiene practices may be the most important method of controlling the disease whether or not fluoride is available or accessible.

Associations between salivary levels of mutans streptococci, lactobacilli, yeasts and black-pigmented Bacteroides spp. and dental variables in elderly dental patients

Multivariate step-wise regression analyses demonstrated that in a population of 146 elderly dental patients (mean age 69.8 yr) the salivary level of mutans streptococci was unrelated to the root DFS score, unlike the levels of lactobacilli and yeasts. Mutans streptococci were related to the wearing of partial dentures and the number of snacks eaten per day, while salivary lactobacillus levels were also related to the number of snacks eaten per day and to denture wearing, and negatively related to saliva buffering. Salivary yeast levels were also related to the wearing of partial dentures and the number of snacks eaten per day, and negatively related to salivary neuraminidase activity. The R2 values ranged from 0.21 to 0.28. Salivary level of black-pigmented Bacteroides spp. were related to maximum CPITN score, mean bleeding index and salivary trypsin-like activity (R2 was 0.08).