Mutans streptococci and caries prevalence in preschool children

Abstract – Numerous studies have reported a correlation between mutans streptococci levels and dental caries. The aim of this study was to assess the relationship between salivary mutans streptococci levels and caries in preschool children of low socioeconomic status. A total of 462 Head Start children, mean age 3.8 yr (range 2.0-5.3 yr), were examined by the modified method of R adike . Saliva samples from 458 of these children were collected with tongue blades and impressed onto mutans streptococci selective agar. Children's mutans streptococci levels were categorized as low (0 CPU), moderate (1–50 CPU) or high (>50 CPU), and the mean dmfs was 0.40, 1.92 and 4.88, respectively. All study groups (Black, Hispanic and White) had infection rates of approximately 83%; however, 39.1% of Black children had high mutans streptococci levels compared with 28.4% of White children. Pit/fissure caries was the most prevalent disease type in children with moderate or high mutans streptococci levels, although White children in the high group had significantly less of this pattern than Blacks and Hispanics. Sensitivity, specificity, and positive and negative predictive values for the high mutans streptococci group were 91.3%, 57.5%. 69.3% and 86.3%. Results from this study indicate that differences between Black, Hispanic and While preschool children may influence caries activity within populations that have similar mutans streptococci infection levels and socioeconomic backgrounds.     

Sodium fluoride and chlorhexidine effect in the inhibition of mutans streptococci in children with dental caries: a randomized,double‐blind clinical trial

Objective: We aimed to compare the effect of sodium fluoride and chlorhexidine on salivary levels of mutans streptococci (MS), in a double‐blind, randomized clinical trial. Methods: Thirty‐five healthy volunteers, aged 4–8 years, with at least one active carious lesion and no previous history of allergies were selected to participate in the study. A gel formulation containing either 1.23% sodium fluoride or 1% chlorhexidine was topically administered to the dentition every 24 h for 6 consecutive days. Salivary MS levels were measured at baseline (D1) and on the 6th (D6), 15th (D15), and 30th (D30) days. For microbiological analysis, Mitis Salivarius‐Bacitracin agar medium was used. Results: Difference between treatments was only verified on D6. On the last day of treatment 1% chlorhexidine gel was significantly more effective than fluoride (P = 0.0000). The use of sodium fluoride did not cause a statistically significant variation in salivary MS levels throughout the duration of the study. Following treatment, a subsequent increase in MS counts between D6 and D15 (P = 0.0001) was observed with chlorhexidine. Conclusion: A 6‐day treatment with a 1% chlorhexidine gel was effective in reducing salivary MS; there was a significant MS increase once treatment was suspended. The use of 1.23% sodium fluoride under the same regimen was not able to reduce salivary MS levels. Our results suggest repeated treatment with 1% chlorhexidine as a means for maintaining low salivary MS levels in children with dental caries.     

Effect of mixed mutans streptococci colonization on caries development

OBJECTIVE: To evaluate the clinical importance of mixed mutans streptococci colonization in predicting caries in preschool children. METHODS: Caries prevalence was examined twice, with a 6-month interval, in 410 preschool children aged 3-4 years at baseline. A commercial strip method was used to evaluate the mutans streptococci score in plaque collected from eight selected interdental spaces and in saliva. Mutans streptococci typing polymerase chain reaction (PCR) assays (Streptococcus sobrinus and Streptococcus mutans, including serotypes c, e, and f) were performed using colonies on the strips as template. RESULTS: Twenty variables were examined in a univariate analysis to predict caries development: questionnaire variables, results of clinical examination, mutans streptococci scores, and PCR detection of S. sobrinus and S. mutans (including serotypes c, e, and f). Sixteen variables showed statistically significant associations (P < 0.04) in the univariate analysis. However, when entered into a logistic regression, only five variables remained significant (P < 0.05): caries experience at baseline; mixed colonization of S. sobrinus and S. mutans including S. mutans serotypes; high plaque mutans streptococci score; habitual use of sweet drinks; and nonuse of fluoride toothpaste. CONCLUSION: 'Mixed mutans streptococci colonization' is a novel measure correlated with caries development in their primary dentition.     

Salivary mutans streptococci and dental caries patterns in pre-school children

Abstract Recent studies have suggested that the identification of caries as discrete patterns may be valuable in describing and predicting caries experience on an individual basis. The purpose of this study was to assess the association between levels of salivary mutans streptococci and the prevalence, incidence and distribution of caries patterns in the primary dentition. A cohort of pre-school children (n=146, mean age 3.8 yr) were examined for dental caries and sampled for salivary mutans streptococci (SMS) at baseline and once annually for 2 yr. Children's tooth surfaces were categorized into four patterns: pit/fissure, maxillary anterior, posterior proximal, and buccal/lingual smooth surface. Salivary mutans streptococci were enumerated using a tongue blade technique, and were categorized as low (0 CPU), moderate (1–50 CPU) and high (>50 CPU). At year 2, children with high baseline SMS had the 1) highest prevalence of caries (87%) and the highest dmfs (9.15); 2) highest prevalence of each pattern, and 3) greatest number of patterns. Among children with the pit/fissure pattern, those with high baseline SMS had the greatest pit/fissure dmfs after 2 yr. Results show that baseline SMS levels were associated with both cross-sectional and longitudinal caries experience, numbers of caries patterns, and the prevalence and severity of those patterns.     

Prevalence of caries and salivary levels of mutans streptococci in 5-year-old children in relation to duration of breast feeding

Abstract – 144 children with a known breast feeding history were studied for their caries prevalence and level of salivary mutans streptococci. 19% of the children were exclusively breastfed for more than 9 months and 38% of the children were weaned after the age of 12 months (max. 34 months). The results of the study showed an equal caries prevalence at the age of 5 among children with a longer or shorter period of exclusive breast-feeding (x²= 3.68, 9 df, NS). Exclusive breast-feeding also did not affect the levels of salivary mutans streptococci (x²= 4.87, 9 df, NS). Children who were weaned late did not differ from those who were weaned early with respect to caries experience (x²= 6.12, 9 df, NS), level of salivary mutans streptococci (x²= 5.49, 9 df, NS) or presence of mutans streptococci (x²= 1.53, 4 df, NS). On the basis of our sample we concluded that breast feeding alone cannot be connected with an increased or lowered caries prevalence.     

Mutans Streptococci and dental caries prevalence in a group of Latvian preschool children

Paraffin-stimulated saliva samples were collected from 140 children 3- and 4-yr old attending nine nursery schools in Latvia. The salivary levels of mutans streptococci were rated from zero to 3 after being cultured on a commercially available strip selective for these microorganisms. Of the children, 29.3% were rated at zero (～10⁴ cfu per ml saliva). This group of children demonstrated the lowest mean caries prevalence dmfs_tot= 1.5 (SD 1.9). The highest dmfs_tot was found among children in class 2 (38.6%; %10⁵-10⁶ cfu/ml) and class 3 (12.1% >10⁶ cfu/ml) with a mean caries prevalence of 6.5 (SD 5.8) and 6.4 (SD 6.0), respectively. The study demonstrates the association between high caries prevalence and high salivary levels of mutans streptococci in the young child. It is suggested that early identification of mutans streptococcicolonized children might be of value in selecting at caries risk children for preventive measures.     

Decreasing caries prevalence in Japanese preschool children is accompanied with a reduction in mutans streptococci infection

OBJECTIVE: To evaluate the association between decreasing caries prevalence in Japanese preschool children and mutans streptococci (MS) infection. METHODS: The prevalence of caries and salivary MS was examined in 1- to 3-year-old preschool children in 1995 (n = 135) and 2000 (n = 118). RESULTS: The caries prevalence for 3-year-old subjects significantly declined from 65.1% to 37.5% (p < 0.01), reflecting the data seen in Japanese national oral health surveys in 1993 and 1999. Salivary MS detection for 3-year-old subjects significantly declined from 68.3% to 37.5% (p < 0.05). On the other hand, the decrease in the prevalence of caries and salivary MS was not significant in 1- and 2-year-olds. The correlation between caries experience (dft) and the salivary MS score for 3-year-old subjects with low caries prevalence in the later examination (r(s) = 0.479, p < 0.001) was comparable with that in 1995 (r(s) = 0.462, p = 0.001). CONCLUSIONS: The recent decrease in decay in Japan is accompanied with a reduction in MS infection in the deciduous dentition. MS levels are closely related to caries prevalence in preschool children regardless of the extent of caries.     

奶瓶龋儿童口腔变链菌的研究

目的：研究儿童口腔内的变链菌基因型与奶瓶龋易感性的关系。方法：取20名奶瓶龋及20名无龋儿童牙菌斑及唾液接种于TYCSB培养基计数并筛选MS,采用AP－PCR法鉴定变链菌基因型。结果：奶瓶龋组儿童唾液及菌斑变链菌计数高于无龋组;并且有两种以上基因型变链菌的比例也高于对照组（14／20vs 5/20)。结论：患有奶瓶龋的儿童不仅变链菌计数高,而且多数被两个以上基因型的MS感染。     

Dental caries and mutans streptococci in selected groups of urban and native Indian schoolchildren in Mexico

Two groups of Mexican children aged 12-14 yr were examined for dental caries and salivary mutans streptococci counts. One hundred lived in Mexico City and 100 belonged to a native Mazahua Indian population. The prevalence of caries, diagnosed according to WHO, was 90% in Mexico City and 82% in the Indian community. Mean DMFT was 5.98 and 3.57 respectively. Saliva samples were analyzed for mutans streptococci by the "Strip mutans" method. Further identification of the biotype/serotype was done. Mutans streptococci were found in 95% of the urban children and 75% of the Indians. There was a statistically significant difference in the prevalence of mutans streptococci between the city and the rural samples. Streptococcus mutans was more frequently found than Streptococcus sobrinus.     

Bovine milk fermented with Lactobacillus rhamnosus L8020 decreases the oral carriage of mutans streptococci and the burden of periodontal pathogens

Abstract Aim: The aim of this study was to find the oral isolate of lactobacilli, which has the potential to inhibit either periodontal, cariogenic, or fungal pathogens in vitro, and to examine the effects of bovine milk fermented with the isolate on the oral carriage of cariogenic and periodontal pathogens. Methods: The inhibitory effects of the supernatant of Man–Rogosa–Sharpe broth, in which each of 42 oral isolates of lactobacilli grown, was examined. One isolate, Lactobacillus rhamnosus L8020, that showed the potential to inhibit either periodontal, cariogenic, or fungal pathogens in vitro, was used to examine the effects of fermented milk on the oral carriage of cariogenic and periodontal pathogens, which was examined by a placebo‐controlled and cohort trial using 50 participants. Results: Edible yogurt containing Lactobacillus rhamnosus L8020 significantly reduced the oral carriage of mutans streptococci (P < 0.01) and four periodontal pathogens examined: Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Fusobacterium spp. (P < 0.01), but the phenomenon were not observed with the placebo yogurt (P > 0.05). Conclusion: These results suggest that yogurt with Lactobacillus rhamnosus L8020 could reduce the risk of dental caries and periodontal disease.     

Effect of different caries preventive measures in children highly infected with mutans streptococci

Abstract – The caries preventive effect of topical application of fluoride varnish (Duraphat), ferric-aluminum-fluoride solution (FeAlF) and chlorhexidine gel was compared in a 2-yr clinical study. Children with more than 10⁶ mutans streptococci per ml saliva were selected and a total of 189 13-yr-old children participated in the study. The children in the fluoride groups were treated every third month with either Duraphat or FeAlF-solution. In the chlorhexidine group children with more than 2.5 × 10⁵ mutans streptococci per ml of saliva were treated every third month. The mean number of new decayed and filled tooth surfaces was 3.06 in the chlorhexidine group, 5.88 in the Duraphat group, 5.33 in the FeAlF group, and 6.34 in the control group. Thus supervised antimicrobial treatment can significantly reduce the incidence of dental (caries) in children with high numbers of mutans streptococci.     

Salivary mutans streptococci and caries development in the primary and mixed dentitions of children

OBJECTIVES: For more than 25 years, both cross-sectional and longitudinal studies of dental caries have focused on the role of salivary mutans streptococci (SMS) as a predictor of caries risk. This study examined the relationship between SMS and longitudinal caries development in the primary and mixed dentitions. METHODS: Eighty-five children, initial mean age 3.8 years, were examined for dental caries at baseline and once annually for 6 years. Children's SMS were sampled with a tongue blade, which was impressed onto plates containing a medium selective for SMS. After incubation, colony forming units of SMS were determined semi-quantitatively and categorized as low, moderate or high. RESULTS: Children classified as high caries risk at baseline had significantly greater (P<0.05) dmfs scores for all teeth, and in the primary molars, than children classified as moderate or low caries risk at every age but 9 (P<0.10). Children classified as high risk at age 3 had the greatest DMFS increment through age 8. Based on annual examinations, there was a trend towards increasing mean dmfs/DMFS scores among children classified as high risk in every year. CONCLUSIONS: The current study is among the first to report on the ability of annual measurements of SMS to identify long-term caries risk in both the primary and the mixed dentitions. Despite limitations in predicting caries risk using microbiological methods, this longitudinal study supports the overall benefits of this type of testing.     

Effect of removable orthodontic appliances on oral colonisation by mutans streptococci in children

Little is known about the effect of removable orthodontic appliances on oral colonisation by mutans streptococci (MS). In the present study, the frequency of isolation and serotype distribution of MS were evaluated in two groups of children, one undergoing therapy with removable appliances and the other not subjected to any kind of orthodontic treatment, respectively. Streptococci isolated from dental plaque samples from both groups of children were identified as mutans streptococci on the basis of their morphological and biochemical properties and were then serotyped in an enzyme immuno-assay using monoclonal antibodies. The number of subjects harbouring MS in their dental plaque was statistically higher in the group of orthodontic children without caries experience (CF) in comparison with CF children of the control group (10/12, 83.3% vs. 15/44, 34%). No clear difference was observed in the distribution of the different MS serotypes between the experimental and control group: S. mutans c,f serotype was the most frequently isolated in both groups of children followed by S. mutans serotype e and S. sobrinus serotype g. Such results suggest that the use of removable appliances may lead to the creation of new retentive areas and surfaces, which favour the local adherence and growth of MS. The data obtained stress the importance of a careful monitoring of patients treated orthodontically for risk of caries development.     

变异链球菌、乳酸杆菌、双岐杆菌在不同龋患指数儿童唾液中分布情况的比较观察

目的:比较无龋儿童和高龋患儿唾液中益生菌和变异链球菌的分布情况。方法:根据WHO 1997年《口腔健康调查基本方法》中龋病诊断标准,分别选取dmft≥4(高龋组)和dmft=0(无龋组)的5~6岁儿童各30人,于上午9:00-11:00取所有儿童的非刺激性唾液,分别接种于变异链球菌、双歧杆菌、乳酸杆菌的选择性培养基,在37℃厌氧条件下培养48 h后,取各选择培养基HE染色后倒置显微镜观察进行形态学鉴定。进而对各组各菌种菌落单位进行统计学分析。结果:5~6岁儿童口腔中均含有大量变异链球菌,明显高于其他两菌种(P<0.05),但高龋病组与无龋组之间无显著性差异(P>0.05);乳酸杆菌、双歧杆菌均以无龋组最高,与高龋组相比有显著性差异(P<0.05)。结论:乳酸杆菌、双歧杆菌是无龋儿童口腔中的优势菌,可能对降低该年龄段儿童的龋易感性有作用。     

A longitudinal study of caries onset in initially caries-free children and baseline salivary mutans streptococci levels: a Kaplan-Meier survival analysis

OBJECTIVES: To apply survival analysis to a longitudinal study of the relationship between salivary mutans streptococci (MS) levels at baseline in initially caries-free children and caries onset in deciduous, mixed, and permanent dentition. METHODS: The Kaplan-Meier survival analysis method was used to compare survival times to caries onset for initially caries-free children with low levels of MS at baseline with survival times to caries onset for initially caries-free children with high levels of MS at baseline. RESULTS: Data from a 6-year longitudinal study of caries risk in initially caries-free children in Rochester and the Finger Lakes Region of western New York were utilized for this study. Of 464 children analyzed, 327 had a low level of MS and 137 had a high level of MS at baseline. Survival analyses showed that children with a low level of MS at baseline remained caries-free for a longer period than children with a high level of MS at baseline. Statistically significant relationships [hazard ratios (HR)] with onset of caries in deciduous, mixed and permanent teeth were found with high and low levels of salivary MS. CONCLUSIONS: Based on our analysis, we concluded that children who were caries-free at baseline and who had high salivary MS levels at baseline would be at greater risk, i.e. more susceptible to caries onset, at any given time than caries-free children who had low salivary MS levels at baseline. Survival functions for deciduous, mixed and permanent dentitions with their 95% confidence limits have been calculated. Survival analysis for the exploration of longitudinal caries studies has an advantage over traditional statistical methods, as it takes into account censored observations and incorporates the concept of risk over time. Hence, survival analysis is well suited for studying transitions from one health state to another, in this case, from a caries-free state to a caries-active state.     

Lactobacillus paracasei SD1, a novel probiotic,reduces mutans streptococci in human volunteers: a randomized placebo-controlled trial

Objectives

The present study investigates the effect of an oral Lactobacillus paracasei SD1 isolate on a number of salivary mutans streptococci, lactobacilli, and yeasts and to examine whether the strain could persist in the oral cavity after a short period of consumption. The potential side effect of the probiotic was also evaluated.

Material and methods

After informed consent, 40 healthy young adults were recruited and randomly assigned to either the test (A) or placebo (B) groups. Group A received milk powder contained L. paracasei SD1, and group B received standard milk powder once daily for 4 weeks. Salivary mutans streptococci, lactobacilli, and yeasts were enumerated using quantitative differential culture at the baseline and then once a week for 4 weeks after the administration period. The persistence of L. paracasei SD1 was also investigated using AP-PCR for the DNA fingerprinting.

Results

A statistically significant reduction in mutans streptococci counts occurred within group A compared to the baseline B (P?<?0.05) along with a non-statistically significant reduction in yeast counts. A significant increase in lactobacilli numbers occurred in group A (P?<?0.05), and the probiotic strain could be detected up to 4 weeks following cessation of dosing.

Conclusions

Our results demonstrate that short-term daily ingestion of the human-derived probiotic L. paracasei SD1 reduces the number of oral mutans streptococci.

Clinical Relevance

L. paracasei SD1 may help to decrease the risk of dental caries, and this organism may be a useful probiotic organism for dairy products.     

Salivary lactobacilli explain dental caries better than salivary mutans streptococci in 4–5-year-old children

The present comparative study was undertaken to determine which of the bacteria, lactobacilli (Ibc) and mutans streptococci (ms), in saliva better explains the variation of caries in 2728 South African 4–5-yr-old children. Caries was diagnosed according to WHO criteria. For Ibc, the Dentocult system was used. The number of ms in stimulated saliva was counted on MSB agar plates. For correction of confounding factors, data on the frequency of intake of sweets were derived from extensive interviews. Oral hygiene was determined according to the simplified debris index of G reene & V ermillion. Simple correlation analyses between dmfs and bacterial counts were done for the total material and for three caries intervals by calculating Spearman's and Pearson's coefficients of correlation. Multivariate regression analyses were done on all intervals to correct for the confounding effects of regular intake of sweets, presence of salivary ms or Ibc, and oral hygiene. Of the children, 68% had detectable Ibc in the saliva, and 74% had ms. Except for children with more than 6 dmfs, the explanatory values, i.e., percentage of variation in dmfs explained, were higher for Ibc than for ms. Before correction, the values for the total material were 15 vs 6%; for children with caries, 7 vs 5%; for those with 1–6 dmfs, 5 vs 0.4%; and for those with more than 6 dmfs, 0.3 vs 2%. All γ -values were reduced after correction, indicating that the confounders explain some of the correlation between dmfs and bacterial count. As was the case before correction, the percentage of variation in dmfs explained by Ibc after correction was higher than that for ms, except for children with more than 6 dmfs. The results suggest that Ibc explain the variation in caries among preschool children better than ms, but the question of whether Ibc is a belter predictor remains.     

Dental caries, mutans streptococci, lactobacilli, and saliva secretion rate in adults

In 718 Swedish patients, equally divided into four age groups (19-25, 26-45, 46-60, greater than 60 yr), salivary levels of mutans streptococci and lactobacilli, saliva secretion rate, and DMFS were registered. No significant differences were found between the various age groups either in salivary factors or in caries (D). Number of missing (M) and filled (F) surfaces increased with age. Prevalence of root caries, which increased with age, was significantly correlated to number of exposed root surfaces independent of age. Of the total study group, 50% had greater than or equal to 10(6) mutans streptococci and 40% had greater than or equal to 10(5) lactobacilli per mL saliva. Three percent had a saliva secretion rate of less than or equal to 0.5 mL/min. Correlation analyses showed that both mutans streptococci and lactobacilli significantly correlated to the caries prevalence but the r-value never exceeded 0.34.     

Caries prevalence and salivary mutans streptococci in 0–2-year-old children of Japan

The prevalence of caries and the number and species distribution of salivary mutans streptococci in 356 children (aged 0-2 yr old) in Japan were examined twice at an interval of 1 yr. No mutans streptococci were isolated from the predentate children. The detection rate of mutans streptococci and the prevalence of caries increased with age. Mutans streptococci were isolated from 39.9% of the subjects. The majority of isolates were identified as Streptococcus mutans. The concentration of mutans streptococci correlated with the number of erupted teeth (r = 0.339). In addition, the concentration of mutans streptococci was more closely correlated to the caries prevalence of the next year (r = 0.465) than that of the year when the salivary concentration of mutans streptococci was first evaluated (r = 0.368). The children who had no caries but harbored mutans streptococci in the first year showed significantly higher caries prevalence in the next year than did the children with neither caries nor mutans streptococci. These results indicate that the establishment of mutans streptococci is associated with caries initiation in early childhood.