On the pH-lowering potential of lactobacilli and mutans streptococci from dental plaque related to the prevalence of caries

Abstract The common method used today to identify persons at risk of dental caries is to estimate the numbers of cariogenic bacteria such as lactobacilli and mutans streptococci in saliva or plaque samples taken from the patient. However, the value of these bacterial counts for explaining and predicting individuals at risk of caries has not been powerful enough. Evaluating one virulence factor such as the acidogenicity of these bacteria might increase their explanatory values for caries. Sixty children aged 14–15 yrs participated in this study. Smooth surface caries and restorations were registered and total plaque samples collected. Counts of lactobacilli and mutans streptococci were estimated, and the pH-lowering potential of both bacteria was measured in an adapted glucose broth. The results showed a weak association between dental caries and lactobacilli, but in the subgroup with this bacterium the explanatory value increased to 14% and in the subgroup with a strong pH-lowering potential it was as high as 27%. For mutans streptococci the associations were weak in all groups.     

Microbial flora associated with presence of root surface caries in periodontally treated patients

Abstract — Examination of saliva and dental plaque was carried out in 35 adults who had been treated for periodontal disease 3 yr earlier. Plaque samples were collected from approximal and buccal sound and carious root surfaces. The samples were analyzed for the presence and proportions of members of Streptococcus, Lactobacillus and Actinomyces. The results showed a low prevalence of root surface caries and a low level of salivary mutans streptococci and lactobacilli. From subjects with root caries there was a not statistically significant tendency to higher proportional levels of mutans streptococci in plaque from carious root surfaces than from caries-free surfaces. An inverse significant relationship between noncarious and carious root surfaces was noted for S. sanguis. The population of A. viscosus and A. naeslundii was similar in plaque samples from sound and carious sites but showed elevated levels in the subjects with five or more new root surface lesions.     

Plaque fluoride and mutans streptococci in plaque and saliva before and after discontinuation of water fluoridation

Our aim was to compare plaque fluoride and the level of mutans streptococci in saliva and plaque before and 1 and 2 years after discontinuation of water fluoridation in Kuopio, Finland. For comparison, a low-fluoride community was included in the study. Pooled plaque and saliva were collected from a random sample of 12-year-olds in both communities ( n =139). Enumeration of mutans streptococci in plaque was made on MSB agar and the level of salivary mutans streptococci was measured using the Strip mutans® method. Fluoride was analyzed using a fluoride specific electrode. Caries, gingival status, fluoride varnish applications and self-reported oral health habits were recorded at baseline. Before discontinuation of fluoridation. the level of mutans streptococci in saliva was significantly lower in the fluoridated than in the non-fluoridated community. The difference in plaque mutans streptococci was not statistically significant. After discontinuation of water fluoridation, there was a significant shift towards elevated values of salivary mutans streptococci in the fluoridated community, but the level of mutans streptococci in plaque remained at the baseline level. There was no significant difference between the communities in the fluoride content of plaque either before or after discontinuation of fluoridation. From the background factors, only caries scores (higher in the non-fluoridated community) and oral hygiene (better in the non-fluoridated community) were significantly different between the communities.     

Proportions of Streptococcus mutans, lactobacilli and Actinomyces spp in root surface plaque

Abstract – The incidence of Streptococcus mutans, lactobacilli and Actinomyces was examined in root surface dental plaque from 24 subjects with root surface caries and in 24 subjects with exposed root surfaces as a consequence of periodontitis but without root surface caries. Plaque was collected from the most posterior teeth in each quadrant: in the caries group from carious lesions and in the periodontitis group from buccal root surfaces. There were significantly higher proportions of S. mutans and lactobacilli in dental plaque samples taken from subjects suffering from root surface caries than in samples from subjects without root surface caries. The level of the group A. viscosus/naeslundii in the periodontitis group was higher than that found in the root surface caries group, but the difference was not statistically significant.     

The earlier the colonization by mutans streptococci, the higher the caries prevalence at 4 years of age

Seventy-eight 4-year-old children, examined earlier for the presence of mutans streptococci at 4-month intervals from 15 months of age, were recalled for recording of dental caries and salivary sampling. The saliva samples were analysed for the presence of mutans streptococci, including the species Streptococcus mutans and Streptococcus sobrinus and lactobacilli. The results showed that the earlier the mutans streptococci had been detected in the children, the higher the caries experience. Eighty-nine percent of the children colonized at 2 years of age had experienced caries and had a mean dfs of 5.0 compared with 25% of the non-colonized 4-year-olds with a mean dfs of 0.3. S. mutans was the predominant species. S. sobrinus was usually found in combination with S. mutans , except in 2 children where S. sobrinus was the only species detected. More children with multiple species had higher numbers of total mutans streptococci and a tendency to higher caries prevalence than children with only S. mutans.     

Mutans streptococci and lactobacilli in breast-fed children with rampant caries.

This study aimed to investigate the prevalence of selected components of the oral microflora in breast-fed children who developed rampant caries (resembling nursing caries) under hitherto unexplained circumstances. Dental plaque and saliva samples were collected from breast-fed children, aged between 1 and 2.5 years, with and without rampant caries. Mutans streptococci and lactobacilli were isolated from dental plaque of all children with rampant caries and from most caries-free children. None of the colonies of mutans streptococci resembled those of Streptococcus sobrinus. The mean counts of the mutans streptococci and lactobacilli were 100-fold higher in plaque samples from children with rampant caries as compared with caries-free children. No difference could be found between the numbers of mutans streptococci in plaque overlaying cavities and that from adjacent sound enamel. In contrast, the counts of lactobacilli in plaque were approximately 100-fold higher from cavities than from sound surfaces. The levels of mutans streptococci in saliva were directly related to the presence of rampant caries. The results show that caries-free and caries-active breast-fed children, aged 1 to 2.5 years, harbour mutans streptococci and lactobacilli on their teeth. Rampant caries in these children can occur in the absence of nursing bottles or any other feeding abuse during weaning and in the presence of an aciduric plaque microflora, as has been reported for children with nursing bottle caries.     

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.     

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.     

Streptococcus mutans-like bacteria from human dental plaque in a Sri Lanka (Ceylon) population

Abstract – This paper reports on the presence of low numbers of Streptococcus mutans among the oral streptococci present in human dental plaque in a Sri Lanka (Ceylon) population, where the caries activity is low and a low sucrose intake is combined with the presence of heavy plaque deposits. Plaque samples of unknown age were collected from 10 individuals in a tea estate, and another 10 samples were collected from dental students 19 days following interruption of oral hygiene. Of 670 such strains of oral streptococci studied, none showed typical "frosted glass" colony morphology on Mitis Salivarius agar. However, when subjected to physiological tests 14 of them were classified as S. mutans.     

Association of the microbial flora of dental plaque and saliva with human root-surface caries

Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience. From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion. Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli. A sample of saliva was obtained from about one-third of the subjects for determination of the concentrations of mutans streptococci and lactobacilli. The main observations were: (1) Subjects without root-surface caries or restorations (group I), as compared with subjects with root-surface caries with or without restorations (group II), were characterized by having a lower prevalence and proportion of mutans streptococci and a higher prevalence and proportion of A. naeslundii in plaque on sound root surfaces; (2) subjects in group I also tended to have a lower salivary concentration of mutans streptococci and lactobacilli than subjects in group II; (3) dental plaque on sound surfaces in group II subjects contained a lower proportion of mutans streptococci than plaque associated with incipient or advanced lesions; and (4) the prevalence and proportion of lactobacilli in plaque associated with sound as well as carious root surfaces were very low. The data reinforce findings from other studies and indicate that, as for coronal caries, the plaque and saliva populations of mutans streptococci specifically are correlated positively with the presence of root-surface caries.     

Inconsistent levels of mutans streptococci and lactobacilli measured in stimulated whole saliva

The counts of mutans streptococci (MS) and lactobacilli (LB) in saliva have been used for prediction of dental caries. The results have not justified putting the methods into clinical practice as the explanatory values of the bacteria for caries are low. There is therefore reason to question how representative the methods for sampling and estimation of those bacteria are. The aims of this study were to investigate if the variation in caries is better explained by the bacteria, estimated as means of numbers in double saliva samples, than by numbers in single samples, and to determine whether chewing on either the preferred or the non-preferred side influences the bacterial counts. Twenty-five healthy subjects were included in the study. Two saliva samples were collected with a 1-wk interval by chewing on a piece of sterile paraffin wax on the preferred side only. One month later this was repeated on the opposite side. In order to test if there were variations in the numbers of bacteria due to the laboratory methods, a paired cultivation of 20 samples was carried out. The results showed that the coefficients of variation (c.v.) for the differences between the individual double samples varied between 110 and 276% of the total mean of the double samples. The paired cultivation gave r valves for MS of 0.93 and for LB of 0.99. Using double samples did not increase the explanatory values for caries. There were higher explanatory values for caries on the preferred side than on the non-preferred side, this being much more pronounced for lactobacilli than for mutans streptococci.     

Streptococcus mutans, lactobacilli and dental health in 13–14-year-old Swedish children

Abstract The dental health and the prevalence of Streptococcus mutans and lactobacilli were examined in 101 13–14-year-old children. The average number of decayed (incipient caries) and filled surfaces (DFS) was 10.1 and 12.8, respectively. S. mutans was not detected in 11% of the children while 21% had 10⁶ or more S. mutans per ml saliva. Lactobacilli were not found in 21% of the children whereas 11% had 10⁵ or more lactobacilli per ml saliva. Statistically significant correlations were found between S. mutans and lactobacilli, S. mutans and DFS, lactobacilli and DPS and S. mutans plus lactobacilli and DFS. Increasing numbers of S. mutans and lactobacilli, alone and in combination, were associated with an increased caries frequency.     

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.     

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.     

Risk factors for dental caries in children with cerebral palsy

This study was conducted to examine the oral condition and the salivary and microbiological parameters associated with dental caries in 62 children with cerebral palsy, who came from households of low socioeconomic status (Study Group). This group had mixed (6 to 11 years old) and permanent (11 to 16 years old) dentition. Dental examinations were performed to measure dental caries, plaque index, salivary levels of mutans streptococci and lactobacilli, salivary flow rate, pH of stimulated saliva, and buffer capacity of saliva. A group of 67 non-handicapped children from similar socioeconomic backgrounds also were examined using these parameters (Control Group). Data were analyzed statistically by non-parametric tests and by correlation. The results showed that children with cerebral palsy who had permanent dentitions had a higher mean decayed, missing and filled surfaces index, as well as a higher plaque index for both sexes. Microbiological examination revealed higher levels of mutans streptococci among Study Group subjects with mixed dentition than in the Control Group. Also, lactobacillus counts were higher in the Study Group, regardless of sex or dentition. With respect to salivary flow rate, pH and buffering capacity, lower mean values were obtained for the Study Group.     

Results with the caries activity test "Cariostat" compared to prevalence of mutans streptococci and lactobacilli

The colorimetric test, Cariostat (Sankin, Japan), for measuring the caries activity, based on the presence of acidogenic microorganisms, was evaluated. The results were compared with the prevalence of mutans streptococci and lactobacilli in the samples. Pure cultures of S. mutans and lactobacilli were inoculated into the test medium. A maximum color change from blue to yellow was not obtained not even when large numbers of bacteria were used. Samples of stimulated saliva and plaque samples from people with different salivary levels of mutans streptococci and lactobacilli were inoculated into the test medium. Samples with very low or very high numbers of cariogenic bacteria were found in all score groups indicating that the Cariostat test did not satisfactorily differentiate samples with low or high numbers of microorganisms associated with dental caries.     

鸡卵黄特异抗体对人牙菌斑中变形链球菌影响的体内研究

目的　探讨鸡卵黄特异抗体(IgY)对健康人牙菌斑中变形链球菌构成比的影响。方法　选择志愿受试者24人,随机分为3组:实验组(9人)使用1·5% IgY;阳性对照组(9人)使用1·7 mmol/L洗必太溶液;阴性对照组 (6人)使用PBS缓冲生理盐水,各组均于饭后用药含漱1 min,持续3周。分别于用药前、用药中1、2、3周及停药后 1、3、5周记录菌斑指数,并收集光滑面集合菌斑样本在MS及MSB培养基中微需氧环境培养,检测菌斑中口腔链球菌群及变形链球菌的菌落形成数,分析各组使用药物前后菌斑中变形链球菌所占比例的变化及变化的延续性。结果　应用IgY后,其菌斑指数无明显改变,但牙菌斑中变形链球菌群在口腔链球菌群中的比例明显降低,并且在较长时间内(停药后5周)保持菌斑中变形链球菌的低水平。结论　IgY处理后牙面菌斑的菌群微生态发生改变,为进一步研究牙菌斑微生态防治打下基础。     

A comparison between different methods for prediction of caries activity

Abstract— The aim of the study was to find out if any of the following factors, alone or in combination, could be used for prediction of caries activity: salivary) S. mutans , salivary lactobacilli, buffer capacity, saliva secretion rate, salivary p^H, the amount of plaque and the caries freguency. The patient material consisted of 300 children between 9 and 12 years old. The increment of caries after 1 and 2 years was compared with all the above factors registered at baseline. Only the factors caries frequency and S. mutans showed a significant correlation to caries activity. In one of the tests the lactobacillus count approached significance. The combination of high numbers of incipient smooth surface lesions, S. mutans and lactobacilli gave a mean value of caries activity almost three times that of the whole group (8.4 versus 3. I).     

Impact of oral hygiene and use of fluorides on caries increment in children during one year

The aim of this study was to assess the modifying effect of oral hygiene, and the use of fluorides on caries increment in children when frequency of meals, intake of sugars and prevalence of lactobacilli and S. mutans in the saliva were known. In 8- and 13-yr-olds it was possible to show that children with a low caries increment (0-2 surfaces) had lower mean values for frequency of meals, daily sucrose consumption and prevalence of lactobacilli and S. mutans in the saliva than children with a high caries increment (greater than or equal to 3 surfaces). There were higher mean values in the low caries-increment groups for toothbrushing frequency, use of fluoridated toothpaste and NaF-mouthrinse. Gingival bleeding index (GBI %) was used as an objective measure of oral hygiene and revealed statistically significant differences between the two groups in both age groups (P less than 0.05, P less than 0.01) with the highest scores recorded in the high caries-increment groups. Using as discriminating variables number of meals/day, daily consumption of sucrose and other sugars and number of lactobacilli and S. mutans in the saliva, 77% of the 8-yr-olds and 70% of the 13-yr-olds were correctly classified with regard to net caries increment. If GBJ %, tooth-brushing frequency, use of fluoridated toothpaste and NaF-mouthrinse were included in the analysis another 4% of the 8-yr-olds and 11% of the 13-yr-olds could be correctly classified.     

Effect of an essential oil-containing antiseptic mouthrinse on plaque and salivary Streptococcus mutans levels

BACKGROUND: Clinical studies in which antimicrobial mouthrinses were shown to have significant antiplaque activity most frequently have used gingivitis as the clinically relevant endpoint. However, there is evidence to suggest that mouthrinses containing active agents effective against Streptococcus mutans, such as chlorhexidine, may also have a role in inhibiting dental caries. This clinical study was conducted to determine the effect of 2x-daily rinsing with an essential oil-containing antiseptic mouthrinse (Listerine Antiseptic) on levels of recoverable S. mutans and total streptococci in supragingival interproximal plaque and in saliva. Additionally, a follow-up in vitro study is reported which determined whether a differential susceptibility to the antiseptic mouthrinse exists among different strains of streptococci. METHOD: Following baseline saliva and plaque sampling for quantification of recoverable S. mutans and total streptococci, 29 qualifying subjects were randomly assigned either the essential oil mouthrinse or a sterile water control. They rinsed with 20 ml for 30s 2 x daily for 11 days and once on the 12th day, in addition to their usual oral hygiene procedures. On day 12, saliva and plaque samples were again collected and microbiological quantification performed. The procedures were repeated with the alternate rinse after a 1-week washout period. RESULTS: The essential oil mouthrinse produced respective reductions of 69.9% and 75.4% in total recoverable streptococci and in S. mutans in plaque, and corresponding reductions of 50.8% and 39.2% in saliva. The in vitro study revealed that streptococci from the mutans group were more susceptible to the bactericidal activity of the essential oil mouthrinse than streptococci from the mitis group. CONCLUSIONS: As antimicrobial mouthrinses are most frequently recommended to patients whose mechanical oral hygiene procedures are not adequate for the control of supragingival plaque and gingivitis, this study provides an additional rationale for the inclusion of the essential-oil mouthrinse as an adjunct to daily oral hygiene procedures.