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.     

Relationship between mutans streptococci in saliva and their colonization of the tooth surfaces

The relationship between the salivary concentration of mutans streptococci and their prevalence on different tooth surfaces was studied in 114 subjects. Plaque samples were obtained from all tooth surfaces in the dentition and the infection magnitude of mutans streptococci was determined. The salivary concentrations of mutans streptococci correlated significantly with the number of colonized tooth surfaces and with the infection level of mutans streptococci for individual teeth or groups of tooth surfaces. The highest correlation values were found for buccal and approximal surfaces and for molars followed by premolars and anterior teeth. The 10 tooth surfaces best reflecting the salivary levels of mutans streptococci were 5 buccal and 5 approximal sites, 6 of them localized on maxillary posterior teeth. A significant positive relationship was noted between the prevalence of mutans streptococci in saliva and on the dorsum of the tongue.     

The toothpick method in relation to other plaque sampling techniques for evaluating mutans streptococci

The aim of the present study was to compare the use of toothpicks with other sampling methods for determination of mutans streptococci on different tooth surfaces. In nine persons with > 10⁵ CPU per ml saliva of mutans streptococci, plaque samples were taken from 90 buccal and lingual surfaces. 108 occlusal surfaces and 90 approximal surfaces with toothpicks. The prevalence of mutans streptococci on these tooth surfaces was compared with samples taken at four 1-week intervals on the same tooth surfaces with a carver (buccal/lingual surfaces), a needle (occlusal surfaces) or a dental floss (approximal surfaces). Each sample was plated on MSB agar and the presence of mutans streptococci was expressed on a scale varying from 0 to 4. On two of the sampling occasions the amount of plaque, mirrored by total viable counts on blood agar, was also determined. Only for buccal/lingual plaque samples was a difference in total counts between methods noted and then with higher total recoveries obtained after sampling with toothpicks. More surfaces were found to be positive for mutans streptococci when samples were taken with a toothpick than with a carver, needle or floss. On surfaces positive for mutans streptococci the colonization score was higher in samples taken with a toothpick than with a carver or a needle while samples taken with a floss showed a tendency to higher levels of mutans streptococci than samples collected with a toothpick. The data indicate that the results obtained by using toothpicks for evaluating the prevalence of mutans streptococci an individual tooth surfaces compare favorably with the other methods tested     

HLA class II alleles and salivary numbers of mutans streptococci and lactobacilli among young adults in Japan

To investigate the genetic predisposition toward the accumulation of oral microorganisms, the association between the alleles of HLA-DQA1, -DQB1 and -DRB1 and the salivary numbers of mutans streptococci and lactobacilli were examined in 102 young adults in Japan. HLA-DQA1*0102, DQB1*0604, DRB1*0802, and DRB1*1302 were weakly associated with the numbers of lactobacilli in saliva samples (P<0.05). HLA-DQB1*0601 was associated with the salivary numbers of mutans streptococci (P<0.01). Two HLA class II haplotypes, HLA-[DRB1*0802-DQA1*0301-DQB1*0302] and HLA-[DRB1*1302-DQA1*0102-DQB1*0604], were also weakly associated with the salivary numbers of lactobacilli (P<0.05). These observations suggest that HLA class II alleles may be related to the salivary populations of oral microorganisms, such as mutans streptococci and lactobacilli.     

Influences of orthodontic appliances on oral populations of mutans streptococci

A study was conducted to assess the influence of fixed appliances on the mutans streptococcal in a group of patients receiving orthodontic treatment. Mutans streptococcal counts in stimulated saliva of 27 patients were obtained at baseline, and at 1-month intervals for 4 months. The difference in mutans streptococcal counts at baseline and at the 4-month sampling was less than an order of magnitude in 18 of the patients, between 1 and 2 orders of magnitude in eight of the patients, and 3 orders of magnitude in one patient. Restriction endonuclease digests of genomic DNA from representative mutans streptococci isolates taken from baseline and 4-month saliva samples, as well as from 4-month tooth and appliance surfaces, were examined by pulsed field gel electrophoresis, after restriction endonuclease digestion. Results of the DNA banding patterns associated with isolates from 19 patients showed that, for 12 patients, all isolates examined represented the same clone of Streptococcus mutans, whereas for six patients two different S. mutans clones were detected. One patient yielded three different clones of S. mutans. A much larger number of baseline, as well as post-appliance, isolates will have to be examined from each patient in future studies, in order to determine if the number of different S. mutans clones harbored by individual patients is related to orthodontic treatment.     

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.     

Intraindividual variations in counts of mutans streptococci measured by "Strip mutans" method

Abstract— Intraindividual variations in the mutans streptococci measured by Strip mutans, in a 1-day and a 5-day period, as well as the effect of toothbrushing, were investigated. 30 subjects participated, and their levels of salivary mutans were estimated by a scale containing four steps. With the exception of three comparisons, time intervals of different lengths did not cause a deviation of more than one step. Comparisons made before and after toothbrushing yielded the same score in 22 cases, whereas two subjects showed a discrepancy of two steps. Clearly, in a short-term perspective, variations can certainly be found, but more pronounced discrepancies are rare.     

Prevalence of mutans streptococci in one-year-old children

Colonization with mutans streptococci was studied in 1095 1-year-old children living in suburban Stockholm. During a scheduled vaccination appointment at a child health centre, a bacterial sample was obtained from the child's tongue and a structured questionnaire was completed by the accompanying parent. Six percent of the subjects were colonized with mutans streptococci. The variables most strongly correlated with presence of mutans streptococci were: non-Swedish background, consumption of sugar-containing beverages at night and total consumption of sugar-containing beverages. The results indicate that, by the age of 1 year, maternally influenced behaviour patterns such as dietary habits that may predispose to early colonization of mutans streptococci are already established. Such early colonization with mutans streptococci may predict high caries risk in the primary dentition.     

Factors influencing oral colonization of mutans streptococci in young children

This paper aims to critically review current knowledge about the key factors involved in oral colonization of the cariogenic group of bacteria, mutans streptococci (MS) in young children. MS, consisting mainly of the species Streptococcus mutans and Streptococcus sobrinus, are commonly cultured from the mouths of infants, with prevalence of infection ranging from around 30 per cent in 3 month old predentate children to over 80 per cent in 24 month old children with primary teeth. MS is usually transmitted to children through their mothers, and the risk of transmission increases with high maternal salivary levels of MS and frequent inoculation. Factors that affect the colonization of MS may be divided into bacterial virulence, host-related and environmental factors. Complex interaction among these factors determine the success and timing of MS colonization in the child. As clinical studies have shown that caries risk is correlated with age at which initial MS colonization occurred, strategies for the prevention of dental caries should include timely control of colonization of the cariogenic bacteria in the mouths of young children.     

Interference of oral hygiene products with an adhesion-based assay of salivary mutans streptococci

Abstract – The effect of several oral hygiene products on an adhesion-based assay for salivary mutans streptococci (Dentocult-SM Strip Mutans) was studied in three women. The mutans streptococci levels were recorded for up to 24 h after a 1-min rinse with the product. The chlorhexidine (0.05%) and stanno-amine fluoride solutions (corresponding 0.025% F) interfered selectively with the adhesion-based assay. No such effect was observed for a polyvidoneiodine solution (10 μg/ml) or two toothpastes containing either sodium lauryl sulfate or amine fluorides. The results indicate that antimicrobial agents showing retention in the oral cavity may interfere for several hours after their use with adhesion-based assays of salivary mutans streptococci.     

Effect of xylitol gum on the level of oral mutans streptococci of preschoolers: block-randomised trial

Objectives: To assess the influence of xylitol chewing gum consumption on mutans streptococci level of 3–4 years old Japanese preschoolers. Methods: 248 participants were examined regarding caries‐related factors at baseline and were followed up at 6, 9, and 12 months after the baseline: assessors were blinded, subjects were open labelled and blocked parallel randomised; 142 were selected to use xylitol gum for 3 months (from months 6 to 9) and 106 were controls. Results: 161 participants were analysed (xylitol n = 76, control n = 85). Nineteen caries‐related variables, including xylitol gum consumption, were analysed for any association with the main outcome, plaque mutans streptococci scores development within the intervention period, by logistic regression. Six showed statistically significant associations by univariate analysis (P < 0.05). However, only xylitol gum consumption remained a significant negative association (P < 0.05) by multiple analyses. Interestingly, over 10% xylitol group children experienced diarrhoea, which was larger than previous investigations. Conclusion: Xylitol gum is effective in avoiding increased plaque mutans streptococci in young children.     

Effect of antibody in gingival crevicular fluid on early colonization of exposed root surfaces by mutans streptococci

The effect of antibody to Streptococcus mutans in gingival crevicular fluid (GCF) on the recolonization of cleaned buccal root surface sites by indigenous mutans streptococci was studied. Seven subjects (mean age = 64 years) were selected from a population of 28 on the basis of the presence of appropriate sites with and without detectable immunoglobulin G (IgG) antibody in GCF to formalin-killed S. mutans and adequate levels of mutans streptococci in saliva available for root surface recolonization. Root surfaces exposed to GCF that did or did not contain antibody were then cleaned and sampled for residual plaque organisms (total cultivable flora and mutans streptococci) directly after cleaning (time 0) as well as 24 h later. One subject failed to recolonize at 24 h at any (antibody-positive or antibody-negative) experimental site. For each of the remaining 6 subjects, the mean levels of mutans streptococci (mean percentage of total flora) were lower at sites with IgG antibody to S. mutans in GCF than at antibody-negative sites in the same subject. In each of the 6 subjects, the site with the highest recolonization level was antibody-negative. Comparison based on intra-subject randomization of sites suggested diminished recolonization of mutans streptococci at sites with antibody 24 h after cleaning. The results support the idea that antibody in GCF can modify the early colonization of gingival root surface areas by potentially cariogenic plaque bacteria such as mutans streptococci.     

Sample, count, identify, and store the mutans streptococci

Abstract – According to a new method for sampling mutans streptococci, "Strip mutans", a plastic strip is contaminated by human saliva and incubated in a selective broth. After growth the strip with adherent colonies may be dried and stored. We wanted to know for how long a time bacteria in the colonies were viable if the strips, were stored under different conditions. The survival time is important if the bacteria need to be subjected to further analyses. The results showed that the viability of the bacteria after the incubation period was at least l yr when the strips were stored frozen or frozen in glycerine. Stored dried in room temperature the survival was about 8 wk. A second part of the study aimed at identifying the colonies on strips obtained from different countries. Dried strips were sent air mail to our laboratory for biochemical and immunological analyses and the results showed that serotype/biotype c/e/f of S. mutans were most frequent but d/g S. sobrinus was also present in the samples, which came from Brazil, Greece, and Sweden. Three colonies of 213 on these strips did not grow, possibly indicating non-mutans bacteria.     

母亲唾液变形链球菌水平与幼儿变形链球菌检出关系的研究

目的：研究母亲唾液中变形链球菌水平与幼儿变形链球菌检出的关系。方法：选取北京市海淀区124对1～2岁幼儿和母亲,检测母亲刺激性唾液中变形链球菌水平及幼儿菌斑中变形链球菌检出情况,问卷获取幼儿看护信息。结果：在50对主要看护母亲和幼儿中,幼儿变形链球菌检出阳性组和阴性组的母亲唾液中变形链球菌水平分布的差异有统计学意义;母亲唾液变形链球菌水平较高组的幼儿变形链球菌检出率明显高于较低组的幼儿变形链球菌检出率,差异有统计学意义。而在74对非主要看护母亲和幼儿中,以上组间差异均无统计学意义。结论：主要看护母亲是幼儿变形链球菌的主要传播源,而非主要看护母亲可能不是幼儿变形链球菌的主要传播源。     

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.     

Influence of transient salivary flora on assessment of mutans streptococci level by the "Strip mutans" method

The Dentocult SM ("Strip mutans") method occasionally shows decoloration of broth and of colonies of mulans streptococci on the plastic strip, thereby making interpretation difficult. In an attempt to explain the phenomenon and to investigate the influence of the salivary flora on the "Strip mutans" method, a total of 46 subjects were sampled. Saliva was analyzed using the "Strip mutans" method and conventional plating techniques to identify mutans streptococci, enterococci, staphylococci, enteric bacteria, and yeasts. Approximately 85% of the "Strip mutans" scores coincided with the conventional MSB-plating method. Two samples showed decolored mutans streptococci colonies on the "Strip mutans" strip. Enterococcus spp. were present in the saliva of these test subjects and could grow in the "Strip mutans" broth. Enterococcus faecalis was able to induce the same type of decoloration under experimental pure culture conditions. Three "Strip mutans" samples showed small colonies of mutans streptococci, visible only under magnification (× 10–20). Staphylococcus epidermidis was present in these saliva samples and showed heavy growth in the broth. Under experimental pure culture conditions S. epidermidis also inhibited the growth of mutans streptococci to some extent.     

Possible effect of medically administered antibiotics on the mutans streptococci: implications for reduction in decay

The decline in dental caries in children in North America, Scandinavia, Britain, Ireland and many Commonwealth nations is well documented. The multiple uses of fluoride can account for most, but not all, of this reduction. In this investigation, data are provided which suggest a relationship between antibiotic usage for medical purposes and a decline in both mutans streptococci (MS) and caries. Children attending Grades 1 and 2 in the Coldwater, Michigan school system and who reportedly never received antibiotics had significantly higher proportions of MS in the fissure plaques of first molars than subjects who received antibiotics. The level of decay in the primary dentition was inversely related to the reported usage of antibiotics. The frequent usage of antibiotics could reduce the incidence of dental caries by delaying the colonization of the teeth by the MS. This was evaluated by a prospective study in infants to determine what effect reported antibiotic usage would have on the colonization of newly erupting primary teeth. Only 2 of 10 infants cultured at 2 to 3 week intervals for periods up to 1 year after tooth eruption became colonized by the MS. One had never received antibiotics and the second had been on antibiotics for a single 5-day period. Seven of the 8 non-colonized infants had received antibiotic therapy for periods ranging from 10 to 181 days. Both the Coldwater study and the prospective study of infants suggested a relation between frequency of antibiotic usage for medical purposes and the MS levels on the teeth.     

Prevalence of mutans streptococci and lactobacilli in elderly Swedish individuals

Abstract — The number of Streptococcus mutans, Streptococcus sobrinus, and lactobacilli in stimulated whole saliva was examined in 149 elderly persons. More than 10⁶ CFU/ml of mutans streptococci were found in 57% of the subjects and 85% had more than 10⁵ lactobacilli per ml of saliva. There was no difference in the prevalence of mutans streptococci between edentulous and dentate subjects whereas significantly more lactobacilli were detected in denture wearers, S. mutans was most frequent and was found in 72% of the subjects. S. sobrinus, which was carried by 44% of the persons, was found proportionally in more subjects with dentures than in dentate individuals. In most persons with S. sobrinus, S. mutans was also present but in 8% of the subjects only S. sobrinus was detected. The subjects with both S. mutans and S. sobrinus had higher salivary levels of mutans streptococci than individuals with only S. mutans or S. sobrinus.     

Colonization of mutans streptococci in 8- to 15-month-old children

OBJECTIVE: The age at which a child becomes colonized with mutans streptococci (MS) is important for understanding early childhood caries. The aim of this study was to explore the relationship of age with MS colonization in infants. METHODS: Inner-city children (n = 149) between the ages of 8 months and 15 months, inclusive, who reportedly were still using a baby bottle, were sampled for MS. RESULTS: Evidence of MS colonization was seen as early at 10 months of age. For children 12 months old or younger (n = 80), 25 percent had detectable levels of MS; in the 15-month age group, 60 percent were colonized. CONCLUSION: This study suggests that prevention of MS colonization in some populations may need to be initiated prior to the child's first birthday.     

Low salivary IgA activity to cell-surface antigens of mutans streptococci related to HLA-DRB1*04

BACKGROUND/AIMS: Mutans streptococci are found in almost all individuals, though there are large differences in colonization levels between individuals. These differences are not readily explained, though several factors are believed to influence the colonization. One factor is the immune response to mutans streptococci, mainly provided by salivary immunoglobulin A (IgA). In a previous study, differences in salivary IgA reactions to oral streptococci were observed between human leukocyte antigen (HLA)-DR4-positive and DR4-negative individuals. A lower salivary IgA activity to Streptococcus mutans in particular was most pronounced for two DR4 subgroups, DRB1*0401 and *0404. The main purpose of this study was to further investigate, in a larger study group, the salivary IgA activity to antigens of three oral streptococci in relation to different HLA-DRB1*04 alleles. METHODS: Stimulated saliva was collected from 58 HLA-DRB1*04-positive individuals. Whole cell antigen extracts from S. mutans, Streptococcus sobrinus and Streptococcus parasanguis and the streptococcal antigen (SA) I/II were separated in SDS-PAGE, transblotted and detected with diluted saliva (Western blot), and analyzed in a computer program. All distinct immunoblot bands over 100 kDa were recorded and compared in relation to DRB1*04. RESULTS: The immunoblots revealed lower salivary IgA reactions to S. mutans, S. sobrinus and SA I/II, but not to S. parasanguis, for the DRB1*0401- and *0404-positive individuals compared to other DRB1*04 types. For the *0401 subgroup there was a significant association with a lower IgA response to S. mutans. CONCLUSION: The results confirm earlier observations and may also support previous demonstrated association between colonization by mutans streptococci and the serologically defined HLA-DR4.