Mutans streptococci, lactobacilli and caries prevalence in 15 to 16-year olds in G?teborg. Part II.

During the fall of 1987 one hundred and fifty-five 15 to 16-year-olds were examined with regard to caries prevalence, saliva secretion rate and salivary numbers of mutans streptococci and lactobacilli. In 15% of the subjects no mutans streptococci were detected, while 17.7% carried > 10(6) colony forming units (cfu) per ml saliva. The median value was 1.8 x 10(5) cfu per ml saliva. No lactobacilli were detected in 19% of the subjects and 14.3% had > 10(5) cfu per ml saliva. The mean caries prevalence was 21.0, of these 14.1 were incipient lesions. Increased numbers of mutans streptococci and lactobacilli were associated with increasing caries prevalence. Subjects with high numbers of both microorganisms showed about 4 times higher mean caries prevalence than those with low numbers. Streptococcus sobrinus carriers (15%) had both higher mean caries prevalence and a higher proportion of subjects with > 10(6) cfu mutans streptococci per ml saliva than was found in the whole group.     

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.     

Mutans streptococci and other caries-associated acidogenic bacteria in five-year-old children in South Africa

Correlations between mutans streptococci and caries are inconsistent; some studies show that early caries may occur with other bacterial species possessing the ability to survive, interact and compete with mutans streptococci. This study looked at the relationship between mutans streptococci, Lactobacillus, Actinomyces and Veillonella in saliva and plaque collected from four tooth sites in two ethnic groups, with and without caries. All samples were collected and cultured onto selective media. Colonies were enumerated and identified using biochemical tests. Pearson correlations showed low yet statistically significant correlations between plaque mutans streptococci counts and the number of decayed surfaces (ds) and decayed, missing and filled surfaces (dmfs) of primary teeth in blacks and in coloreds (historical race classification). Salivary mutans streptococci counts correlated with ds and dmfs in coloreds. No relationship was found between ds, dmfs and Lactobacillus, Actinomyces or Veillonella numbers. Significant associations were evident between plaque mutans streptococci and Veillonella and Lactobacillus in black children with caries and between plaque mutans streptococci and Actinomyces and Lactobacillus and Veillonella in colored children. Hence, oral microbes are in constant flux but have interrelationships in children with caries.     

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.     

Mutans streptococci oral colonization in 12-30-month-old Brazilian children over a one-year follow-up period

OBJECTIVES: The infection levels of mutans streptococci were investigated during a one-year follow-up in children aged 12 to 30 months attending school nurseries where a sucrose-rich diet was provided. METHODS: Oral levels of mutans streptococci obtained from 101 children at baseline and after a one-year follow-up were compared by age, number of teeth, feeding habits, and presence of visible plaque at baseline. Baseline predictors and changes in mutans streptococci levels during the study were compared to caries incidence after one year. RESULTS: Fluctuations in mutans streptococci levels during the follow-up period were not related to feeding habits or presence of visible plaque. Mutans streptococci levels increased after one year among children aged 12 to 24 months, while a significantly higher proportion of those aged 25-30 months showed a decrease in mutans streptococci levels during the study. Multiple logistic regression analysis suggested that high levels of mutans streptococci (> or = 100 cfu) at baseline were associated with a higher caries increment, while reduction in mutans streptococci was negatively associated with caries incidence. CONCLUSIONS: Our data suggest that despite early mutans streptococci infection and high exposure to sucrose, mutans streptococci may achieve relatively stable levels after 2 years of age. Heavy colonization by mutans streptococci in an early age was related to an extremely high caries incidence during childhood, while decreasing levels of mutans streptococci can be associated to the decrease in caries activity.     

Lactobacillus-mediated interference of mutans streptococci in caries-free vs. caries-active subjects

In order to assess whether naturally occurring oral lactobacilli have probiotic properties, lactobacilli were isolated from saliva and plaque from children and adolescents, with or without caries lesions. The interference capacities of these lactobacilli were investigated against a panel of 13 clinical isolates and reference strains of Streptococcus mutans and Streptococcus sobrinus, as well as against the subject's autologous mutans streptococci, using the agar-overlay technique. Lactobacillus-mediated inhibition differed significantly between the three subject groups (no caries, arrested caries, or active caries), demonstrating increased inhibition in subjects without present or previous caries experience compared to subjects with arrested caries or subjects presenting with frank lesions. Lactobacilli from subjects lacking S. mutans inhibited the growth of the test panel of mutans streptococci significantly better than lactobacilli from subjects who were colonized. Furthermore, subjects without caries experience harbored lactobacilli that more effectively repressed the growth of their autologous mutans streptococci. Twenty-three Lactobacillus spp. completely inhibited the growth of all mutans streptococci tested. Species with maximum interference capacity against mutans streptococci included Lactobacillus paracasei, Lactobacillus plantarum, and Lactobacillus rhamnosus. Naturally occurring oral lactobacilli significantly inhibited the growth of both test strains of mutans streptococci and the subject's autologous mutans streptococci in vitro, and this effect was more pronounced in caries-free subjects.     

Prediction of caries in pre-school children in relation to fluoride exposure

The levels of salivary mutans streptococci and caries experience were used as predictors for caries incidence in 3 groups of pre-school children from areas with different levels of natural and topical fluoride exposure. Altogether 1022 children, 4-5 years of age at baseline, were examined according to the WHO-criteria and followed for 2 years. The low fluoride group ( n =374) had a low fluoride level in the piped water and no topical fluoride applications: the F-varnish group ( n =442) had low water fluoride but semiannual topical applications of a fluoride varnish; the optimal fluoride group ( n =206) had an optimal level of fluoride in the drinking water and semiannual F-varnish applications. The number of salivary mutans streptococci was estimated and scored at baseline with the Strip mutans chair-side method. The sampling procedure was repeated in 337 children of the low fluoride group 3 weeks after baseline. In comparison with the low fluoride group, caries incidence was 30% and 60% lower in the F-varnish and the optimal fluoride group respectively. The caries predictive ability decreased with increasing fluoride exposure. The sum of sensitivity and specificity decreased from 151% (65%+86%) in the low fluoride group to 131% (40%+91%) in the optimal fluoride group. The positive predictive value was highest (62%) in the low fluoride group. Repeated salivary samplings at baseline did not improve the caries predictive power. The results suggest that the overall fluoride exposure should be taken into account when caries risk assessment strategies for preschool children are developed and implemented.     

Prevention of dental caries with chlorhexidine

The presence of > or = 10(6) mutans streptococci per ml saliva may indicate a high caries risk or activity. Individuals exhibiting these high levels of mutans streptococci are ironically called 'millionaires'. It has been demonstrated that the reduction of the mutans streptococci with a series of chlorhexidine gel treatments, reduces the caries incidence in millionaire children. Recently, two chlorhexidine varnishes have been shown to reduce the mutans streptococci in plaque and saliva significantly. It may be expected that the application of these chlorhexidine varnishes may reduce caries incidence in 'millionaires'. It may also be possible to treat individual sites of the teeth that are at risk.     

Prediction of caries incidence in schoolchildren living in a high and a low fluoride area

Abstract – A salivary mutans streptococci test and past caries experience were used as predictors for caries increment in a 3-yr study comprising 655 12-yr-old schoolchildren from two areas with contrasting levels of fluoride in the drinking water. The mean caries (DMFS) increment was similar in both groups during the study period, but a significantly ( p < 0.05) higher incidence of approximal enamel lesions was registered in children from the high fluoride area. In both groups, a statistically significant ( p < 0.05-0.001) positive relationship between salivary mutans streptococci score and/or past caries experience at baseline on one hand and caries increment during the study period on the other was established. The past caries experience was the most powerful predictor of caries risk in both the low fluoride and the high fluoride area. The sum of the sensitivity and specificity was somewhat higher in the low fluoride area (138%) compared to the high fluoride area (123%). The salivary bacterial enumeration used alone or in combination with past caries experience as well as past approximal caries experience were less useful as predictors in both groups. The present findings indicate that the natural fluoride exposure has a limited influence on caries risk assessment and the caries predictive ability of the 'salivary bacterial test and past caries in populations with a low level of disease.     

Clinical efficacy and effects of xylitol wipes on bacterial virulence

The aim of the study was to investigate whether xylitol-wipe use in young children prevented caries by affecting bacterial virulence. In a double-blinded randomized controlled clinical trial, 44 mother-child pairs were randomized to xylitol-wipe or placebo-wipe groups. Salivary mutans streptococci levels were enumerated at baseline, 6 months, and one year. Ten mutans streptococci colonies were isolated and genotyped from each saliva sample. Genotype-colonization stability, xylitol sensitivity, and biofilm formation of these isolates were studied. Despite a significant reduction in new caries at one year in the xylitol-wipe group, no significant differences were found between the two groups in levels of mutans streptococci. Children in the xylitol-wipe group had significantly fewer retained genotypes (p = 0.06) and more transient genotypes of mutans streptococci (p = 0.05) than those in the placebo-wipe group. At one year, there was no significant difference in the prevalence of xylitol-resistant genotypes or in biofilm formation ability of mutans streptococci isolates between the two groups. The mechanism of the caries-preventive effect of xylitol-wipe use may be related to the stability of mutans streptococci colonization. Further studies with genomic characterization methods are needed to determine specific gene(s) that account for the caries-preventive effect of xylitol.     

Mutans streptococci, lactobacilli and caries prevalence in 11-and 12-year-old Icelandic children

Since the caries prevalence has not declined in Iceland as it has in other European countries, it was of interest to study the presence of cariogenic bacteria in Icelandic children. The prevalence of salivary mutans streptococci and lactobacilli was examined in 217 11- and 12-yr-old Icelandic children and was related to their caries prevalence. In 2% of the children mutans streptococci were not found whereas 31% and 35% of the 11-yr-olds and 12-yr-olds respectively carried more than 10(6) CFU per ml saliva. Lactobacilli were not detected in 8% of the children whereas 28% of the 11-yr-olds and 23% of the 12-yr-olds had more than 10(5) CFU per ml saliva. The mean caries prevalence (DFS), initial caries included, for 11-yr-olds was 21.6 and for 12-yr-olds 28.8. Both mutans streptococci and lactobacilli were significantly correlated to each other as well as to caries prevalence. An increased number of these microorganisms, especially the mutans streptococci, were associated with an increased DFS. Children with high salivary counts of mutans streptococci and lactobacilli showed four times higher DFS than children with low numbers. The magnitude of salivary cariogenic bacteria as well as caries prevalence was found to resemble the situation in Sweden 10 yr ago. S. mutans (serotype c/e/f) was carried by all mutans streptococci positive children. S. sobrinus (serotype d/g) was found in 60 children (30.2%). Children with both S. mutans and S. sobrinus had significantly higher salivary counts of mutans streptococci and lactobacilli as well as caries prevalence than children with only S. mutans.     

Longitudinal study of caries,cariogenic bacteria and diet in children just before and after starting school

Fifty 5-yr-old preschool children living in Akranes, a small community in West Iceland known to have a high caries prevalence, were investigated with respect to caries, salivary counts of mutans streptococci and lactobacilli and consumption of cariogenic foods. Fifteen months later, after being in school for half a year, 43 of the 50 children were reexamined and investigated as before. Mean dmfs scores rose from 7.1 to 9.0. but the scores including initial caries rose from 9.7 to 15.3. Mutans streptococci were carried by 84% of children on both occasions with a mean count 2.1 and 3.6 × 10⁵ cfu/ml. Lactobacillus carriage increased from 29 to 38% and the mean count from 5.1 to 13 × 10³ cfu/ml at 6 yr. The frequency of consumption of sugar-containing foods increased from 4.2 to 5.2 intakes per day and between-meal snacks rose from 3.0 to 3.7 per day. Children classified as “misusing” sugar were 59% at 5 yr and 83% at 6 yr. The mean caries score at 6 yr for children “misusing” sugar was 10.7 but only 2.0 for those not misusing sugar. Thus the deterioration in dental health appears, in these children, to be associated with the increased consumption of sweets and other cariogenic between-meal snacks after starting school.     

Mutans streptococci colonization in early childhood caries in Ibadan,Nigeria

PurposeThis study aimed to assess mutans streptococci (MS) colonization in plaque samples of children and its relationship with early childhood caries in Ibadan, Nigeria.MethodChildren from eight nursery schools in Ibadan were examined for caries and 120 children were randomly selected into two groups: caries-free (decayed, missing, or filled primary teeth dmft) = 0) and caries present groups (dmft > 0). Plaque samples were collected with wooden toothpicks and cultured for MS using Dentocult^® SM strips (Orion Diagnostica, Espoo, Finland) at 37 °C for 48 h. The presence of mutans colonization was confirmed by the detection of raised dark blue to light blue colonies on the inoculated strips. Inspection of the growth for raised colonies was done with a magnifying glass (10×). The result from each child was evaluated as follows: Class 0: <10⁴ cfu/ml, Class 1: <10⁵ cfu/ml, Class 2: 10⁵–10⁶ cfu/ml, and Class 3: >10⁶ cfu/ml.ResultsThere was MS bacterial growth on all plaque samples. About 67% of children with caries had high bacterial score (>10⁶ cfu/ml), while 55.2% of caries-free children had low bacterial score (p = 0.033). When bacterial levels were compared with mean dmft, a statistically significant relationship was also observed (p = 0.033). Three-year-old children were observed to be 4.2 times less likely to develop caries (odds ratio (OR) = 0.237, confidence interval (CI) = 0.086–0.651) and children with MS colonization level >10⁶ cfu/ml being 3.6 times more likely to develop caries (OR = 3.63, CI = 1.414–9.34).ConclusionMS prevalence was 100% among children studied and significantly higher levels of MS colonization (>10⁶ cfu/ml) were present in children with caries.     

Effect of long-term consumption of a probiotic bacterium, Lactobacillus rhamnosus GG, in milk on dental caries and caries risk in children.

Lactobacillus rhamnosus GG, ATCC (LGG), has shown antagonism to many bacteria including mutans streptococci. This randomized, double-blind, placebo-controlled intervention study was designed to examine whether milk containing LGG has an effect on caries and the risk of caries in children when compared with normal milk. 594 children, 1-6 years old, from 18 municipal day-care centres were included. The children received the milk with meals from coded containers 5 days a week in the day-care centres for 7 months. The children's oral health was recorded at baseline and at the end, using WHO criteria. The caries risk was calculated based on clinical and microbiological data, comprising mutans streptococcus levels from dental plaque and saliva. The risk was classified as high if the child had a dmft/DMFT or initial caries score >0, and a mutans streptococcus count > or = 10(5) CFU/ml. The results showed less dental caries in the LGG group and lower mutans streptococcus counts at the end of the study. LGG was found to reduce the risk of caries significantly (OR = 0.56, p = 0.01; controlled for age and gender, OR = 0.51, p = 0.004). The effect was particularly clear in the 3- to 4-year-olds. Thus, milk containing the probiotic LGG bacteria may have beneficial effects on children's dental health.     

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.     

Mutans streptococci and lactobacilli in saliva from children with insulin-dependent diabetes mellitus

The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin-dependent diabetic children was compared with a group of healthy children and related to the metabolic control of the disease. The study group, consisting of 94 boys and girls (age 4-19) with type 1 diabetes was matched by sex and age with a non-diabetic control group. Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children. In the diabetic group, total salivary proteins and glucose content of saliva were determined. Data on caries experience were recorded from the dental cards of all children. There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p less than 0.05) lower levels of lactobacilli were found among the diabetic children. The number of lactobacilli was positively correlated (p less than 0.05) to glucose concentration in saliva. There was no difference in the prevalence of caries between the groups. The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.     

Antibacterial treatment needed for severe early childhood caries

OBJECTIVES: To assess the effects of a single 10% povidone iodine application as an adjunct to extensive surgical procedures in the clinical treatment of children with early childhood caries. METHODS: Twenty-two children scheduled for dental treatment under general anesthesia were randomized into either an intervention group (10% povidone iodine), or a control group (phosphate buffered saline). Either povidone iodine or phosphate buffered saline was applied to teeth and soft tissues after prophylaxis and all operative dental procedures, followed by 1.23% acidulated phosphate fluoride gel. Saliva samples taken at baseline, and after 1 hour, 3 weeks and 3 months were assayed for mutans streptococci, lactobacilli and total viable bacteria. Caries lesions were recorded at baseline and at one year. RESULTS: Mutans streptococci and lactobacilli levels in the povidone iodine group were significantly reduced relative to baseline at 1 hour, 3 weeks and 3 months. At one year at least 60% of subjects had new caries lesions in each group, and there was no significant difference in caries increment between the two groups. CONCLUSIONS: Even prophylaxis, fluoride gel application and complete surgical treatment of caries at baseline were insufficient to prevent new caries in over 60% of the patients in these high caries risk infants. Although the one-time treatment with povidone iodine reduced mutans streptococci and lactobacilli levels for up to 3 months this therapy failed to additionally reduce future caries formation over one year, indicating that repeated antibacterial treatments will be needed to control high levels of cariogenic bacteria.     

Mutans streptococci in saliva and dental caries in children living in a high and a low fluoride area

The aim of this study was to obtain information about the quantitative distribution of salivary mutans streptococci and the relation to dental caries in children with contrasting levels of natural water fluoride. A total of 698 schoolchildren aged 12 yr were selected from areas with high (1.2 ppm) or low (0.1 ppm) fluoride concentration in the drinking water. They were all examined for the presence and number of mutans streptococci in saliva by a specially prepared plastic strip, the "Strip mutans" method, cultivated in a selective broth. Data on the caries experience were obtained from the dental records and from bite-wing radiographs. Mutans streptococci were identified in 82% of all children with no difference between the two areas. The number of mutans streptococci was however significantly (p less than 0.05) lower among the children from the high fluoride area than those from the low fluoride area. Children with no detectable or low levels (0-10 CFU) of mutans streptococci had less caries experience than children with moderate or high levels (11- greater than 500 CFU) in both areas investigated.     

Mutans streptococci and lactobacilli in saliva after the application of fissure sealants

Because dental fissures may serve as reservoirs for mutans streptococci, preventive measures should be taken to control microbial concentrations at these sites. This study estimated the influence that sealing permanent first molars would have on the levels of mutans streptococci and lactobacilli in saliva of healthy seven-year-old schoolchildren. Permanent first molars were sealed in 31 children without caries (NC group) and in 32 children with caries (C group). None of the children had caries in their permanent first molars. Conventional methods were used to count mutans streptococci and lactobacilli in saliva before applying the sealant and again at 4 and 12 weeks after application. Baseline counts of lactobacilli and mutans streptococci were significantly higher in the C group. A significant reduction in mutans streptococci was observed in the NC group at 4 and 12 weeks. It was concluded that fissure sealants in permanent first molars can help reduce salivary levels of mutans streptococci in children without caries.     

Relationships between socioeconomic backgrounds, caries associated microflora and caries experience in 12-year-olds in Bosnia and Herzegovina in 2004

AIM: To present the prevalence of dental caries in Bosnia and Herzegovina (BH), to estimate the levels of salivary mutans streptococci and lactobacilli and compare them with caries prevalence in 12-years-old children from different socioeconomic backgrounds. STUDY DESIGN AND METHODS: A survey was carried out in 8 cantons of the Federation of BH (FBH) and in Republic Srpska (RS) in 2004. The final sample included 560 12-year-olds. The clinical examinations focused on dental status, expressed as DMFT index, and they were carried out by one examiner, following WHO standard methodologies. Additionally, the study involved 109 12-years old children from Sarajevo, divided in three groups, based on their socioeconomic background. For measuring lactobacillus and mutans streptococci (MS) count in saliva Dentocult LB and Dentocult SM-Strip Mutans were used. Levels of MS and lactobacilli were expressed as a score between 0 and 3, indicating very low to very high levels of SM and lactobacilli. RESULTS: The average DMFT of the 12-year-olds was 4.16+/-2.92. On average, 91% of the 12-year-olds were affected with dental caries. The SiC Index was 7.41+/-3.31. Investigating the relationship between caries associated microflora and caries experience in children of different socioeconomic status showed the following: significant difference in caries prevalence was found in children with different living conditions, where children with high socioeconomic status had better oral health compared to the other two groups. For mutans streptococci, 25.7% of the children had mutans class 0, 24.8% class 1, 34.9% class 2 and 14.6% class 3. The mean DMFT for mutans class 0 was 3.50, for class 1 was 4.30, for class 2 was 5.62 and for class 3 was 6.0. For lactobacilli, 38.5% of the children had lactobacilli class 0, 25.7% class 1, 23.9% class 2 and 11.9% class 3. The mean DMFT for lactobacilli class 0 was 4.3, for class 1 was 4.9, for class 2 was 4.8 and for class 3 was 6.0. No significant differences in the level of mutans streptococci and lactobacilli were found between the groups. CONCLUSION: There is moderate caries prevalence among BH 12-year-olds (DMFT 4.16+/-2.92). Caries experience varies between children with different living condition but no relation between levels of salivary mutans streptococci and lactobacilli and socioeconomic status of children could be found.