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.     

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。     

婴幼儿龋菌斑生物膜中白色念珠菌的检出情况

目的初步探讨白色念珠菌检出情况与婴幼儿龋（early childhood caries,ECC）的相关性。方法采用CHROMagar Candida、革兰氏染色及厚膜孢子形成试验,对ECC菌斑生物膜中的白色念珠菌进行分离鉴定,并应用Pearsonχ2检验分析白色念珠菌检出情况与ECC关系。结果白色念珠菌的检出率在ECC组中为44.1%,无龋（caries-free,CF）组为19.2%。ECC组中,男、女生白色念珠菌的检出率分别为59.7%、34.9%;CF组中,白色念珠菌检出率男生为21.1%,女生为18.5%。白色念珠菌的检出率与dmft分级的关联系数为0.35。结论白色念珠菌的检出情况与ECC相关,且白色念珠菌的检出情况与dmft的分级具有关联性。     

Quantitative real-time polymerase chain reaction for Streptococcus mutans and Streptococcus sobrinus in dental plaque samples and its association with early childhood caries

Background.  Streptococcus mutans and Streptococcus sobrinus are closely associated with the development of early childhood caries (ECC). Recently, quantitative real-time polymerase chain reaction (qRT-PCR) has been used for rapid and accurate quantification of these bacterial species.
Aim.  This study aims to detect quantitatively the levels of S. mutans and S. sobrinus in plaque samples by qRT-PCR, and to assess their association with the prevalence of ECC in Korean preschool children.
Design.  One hundred and five children (71 months old or younger) were examined and classified into three groups (caries-free, ECC, severe ECC). Dental plaque samples were collected and qRT-PCR was conducted using oligonucleotide primers specific for glucosyltransferase gene ( S. mutans-gtfB , S. sobrinus-gtfU ) and universal primer. Pearson's correlation test was conducted to evaluate the relationship between the dmfs (decayed, missing, or filled surfaces primary teeth) scores and the microbiological findings.
Results.  There was a significant difference between the levels of S. mutans and S. sobrinus in the plaque samples of the three groups ( P  < 0.05). The proportion of S. sobrinus to S. mutans showed strong correlation to the dmfs scores ( r  = 0.748, P  < 0.05).
Conclusions.  The qRT-PCR results of this study showed that children with ECC had higher level of S. mutans and S. sobrinus in their dental plaque samples. The children with higher ratio of S. sobrinus to S. mutans in their dental plaque showed higher incidence of ECC.     

The predominant microflora of nursing caries lesions.

The predominant microflora recovered from infected dentine of 52 carious teeth from 14 children with nursing caries was determined using both selective and non-selective media for the isolation of specific genera and acidified media (pH 5.2) to isolate the predominant aciduric microorganisms, and compared with the microflora of sound enamel surfaces in caries-free children. Streptococcus mutans formed a significantly greater proportion of the lesion flora while Streptococcus oralis, Streptococcus sanguis and Streptococcus gordonii formed a significantly greater proportion of the plaque flora from sound tooth surfaces. The proportions of Actinomyces naeslundii and Actinomyces odontolyticus were significantly greater in the plaque samples than in the lesion samples. Actinomyces israelii formed 18.2% of the flora from the lesions, but was not isolated from the plaque samples. The proportions of Candida albicans, Lactobacillus spp. and Veillonella spp. were also significantly greater in the carious dentine than in the plaque samples. The most frequently isolated lactobacilli were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus rhamnosus. The predominant aciduric flora was S. oralis, S. mutans and A. israelii and these taxa were also isolated from a similar proportion of the lesions at pH 7.0. Strains of S. mutans, L. casei, L. fermentum and L. rhamnosus isolated from individual carious teeth were genotyped using PCR-based methods. Each species was genotypically heterogeneous and different genotypes were recovered from different carious teeth in the same child. These data indicate that the microflora of lesions in the same child is microbiologically diverse and support a non-specific aetiology for nursing caries in which the physiological characteristics of the infecting flora, not its composition, is the major determinant underlying the disease process.     

口腔白色念珠菌与龋病流行因素的相关性分析

目的研究口腔白色念珠菌与龋病流行因素的关系。方法采集119名受检者的口腔牙菌斑,并记录其龋失补指数、年龄、性别、学历、吸烟、饮酒、义齿修复情况。聚合酶链反应法检测白色念珠菌、变形链球菌和发酵乳酸杆菌,计算其阳性率,分析其与龋病流行因素的关系。结果 34名受检者检出白色念珠菌阳性。白色念珠菌阳性者龋均为4.65,患龋率为79.4%（27/34）;阴性者龋均为为3.60,患龋率为68.2%（58/85）,白色念珠菌阳性与龋失补指数呈正相关（r=0.164,P=0.040）。白色念珠菌阳性者的变形链球菌检出率为47.1%（16/34）,阴性者检出率为68.2%（58/85）,差异有统计学意义,白色念珠菌阳性与变形链球菌检出率呈负相关（r=-0.197,P=0.032）。白色念珠菌阳性者中,变形链球菌阳性率高于乳酸杆菌阳性率,分别为47.1%（16/34）和14.7%（5/34）,差异有统计学意义。白色念珠菌阳性与发酵乳酸杆菌、年龄、性别、学历、吸烟、饮酒、义齿均无显著相关（P〉0.05）。结论口腔白色念珠菌可能为龋病的致病因素之一,与变形链球菌可能有拮抗作用。     

Antimicrobial peptides in saliva of children with severe early childhood caries

ObjectiveControversies exist regarding the relationship between the concentrations of antimicrobial peptides (AMPs) and presence of dental caries in children. Thus, the aim of this study was to examine levels of AMPs in saliva of caries-free (CF), early childhood caries (ECC) and severe early childhood caries (S-ECC) children to determine if the levels of these salivary peptides individually or in combinations were related to caries severity and mutans streptococci levels.Design36 to 60 month-old children were selected to participate in this study. Children were grouped into CF group (n = 29), ECC group (n = 25) and S-ECC group (n = 29). Saliva was collected from children for microbiological analysis by culture. Salivary concentrations of cathelicidin LL-37, human β-defensin 2 (hBD-2), human β-defensin 3 (hBD-3) and histatin-5 (HTN-5) were determined by ELISA.ResultsSalivary concentrations of AMPs did not differ among CF, ECC and S-ECC groups. Data showed positive correlations between mutans streptococci levels and salivary hBD-2 or HTN-5. Positive correlations were found between hBD-2, hBD-3, LL-37 and HTN-5. Combinations among AMPs, mainly LL-37, were positively associated with caries levels.ConclusionsSalivary concentrations of AMPs individually were not associated with the severity of early childhood caries. The stimulus of caries appears to trigger a biological response, however, with a combination of these peptides.     

The acid-tolerant microbiota associated with plaque from initial caries and healthy tooth surfaces

The intent of this study was to compare the inherent acid tolerance of bacteria in samples of dental plaque from tooth sites in subjects with and without initial caries. Plaque was collected from approximal surfaces showing early enamel caries and from healthy tooth surfaces in the same subjects, as well as from enamel surfaces of caries-free individuals. In addition to plating on blood agar, the plaque samples were plated directly on non-selective solid agar medium buffered to pH 7.0, 6.0, 5.5, 5.0, 4.5 and 4.0 to avoid any loss of adaptation to acid during primary isolation of plaque bacteria. The results showed that approximately 50% of the total cultivable plaque microbiota from caries, as well as healthy tooth sites, was able to grow at pH 5.5 and 1% at pH 5.0, pH values regarded as critical for the demineralization of tooth enamel. At pH 5.0, members of the genus Streptococcus were the dominant group, but mutans streptococci accounted for less than half of the streptococcal viable count. The other acid-tolerant streptococcal isolates included Streptococcus anginosus, Streptococcus constellatus, Streptococcus gordinii, Streptococcus intermedius, Streptococcus mitis, Streptococcus oralis, Streptococcus salivarius and SStreptococcus sanguis. Analysis of the results indicated that the mutans streptococci in dental plaque were highly variable with respect to acid tolerance, and that both caries and healthy sites harboured significant numbers of mutans streptococci that were not acid-tolerant.     

喀什市3~5岁维吾尔族儿童婴幼儿龋相关因素的主成分分析

目的:应用主成分Logistic回归分析法研究喀什市3~5岁维吾尔族儿童口腔龋病与白色念珠菌检出情况及危险因素的相关性。方法:采用分层整群抽样的方式随机抽取喀什市397名3～5岁维吾尔族健康儿童作为研究对象,对其进行口腔检查及采集牙菌斑,通过分离纯化培养及聚合酶链反应检测白色念珠菌检出情况。同时采用问卷调查家长对儿童的喂养方式、饮食习惯等。对白色念珠菌的检出情况,是否长期使用奶瓶、是否经常吃零食等20个婴幼儿龋病相关危险因素,采用方差极大正交旋转法进行主成分Logistic回归分析。结果:主成分分析结果显示特征值大于1的因子数目有7 个,分别为:细菌因素、喂养/饮食习惯和家族史因子、宿主因素作用因子、口腔卫生习惯作用因子、社会经济背景作用因子、牙周状况作用因子、使用牙线、和性别因子,对总方差的累积贡献率为70.027%。经Logistic回归分析得出牙周状况和性别无统计学意义,其他因子均与婴幼儿龋病密切相关。结论:喀什市儿童龋病的发生是由多种因素共同作用的结果,除宿主自身因素、饮食习惯等因素外,白色念珠菌的检出也与龋病密切相关。运用主成分分析法构建的综合评价模型可以消除原始变量间的信息重叠,精简数据,客观、合理、综合地评价婴幼儿龋病危险因素的相关性,为当地儿童龋病的防治提供理论依据。     

Relationship among dental plaque composition,daily sugar exposure and caries in the primary dentition

The relationship among daily sugar exposure, dental plaque composition and caries patterns in the primary dentition is not known. Three groups of 20 children (18-48 months old) were studied: (1) caries-free (CF), (2) presenting pit and fissure caries (PFC), and (3) with nursing caries (NC). Dental caries index (dmfs) was assessed and the frequency of daily sugar exposure (TS) and its forms were estimated by questionnaires. Fluoride (F), calcium (Ca), inorganic phosphorus (P(i)), insoluble polysaccharide (IP) and mutans streptococci were quantified in dental plaque. The three groups of children were statistically different regarding daily sugar exposure. Concentrations of F, Ca and P(i) were lower and the IP and mutans streptococci statistically higher in dental plaque from NC children than those from CF children. PFC children also showed statistically lower F and P levels in their plaque than CF children. Statistically significant correlations were found between IP, TS and dmfs from NC and PFC children. A statistically significant correlation between mutans streptococci in plaque from anterior teeth and dmfs for NC children was also observed. These results suggest that the dietary sugar experience changes the biochemical and microbiological composition of dental plaque, which could partly explain the different caries patterns observed in primary dentition.     

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.     

A long-term effect of caries-related factors in initially caries-free children

Aim.  The aim of this study was to examine the rate and pattern of early childhood caries development in caries-free children based on their dental plaque accumulations, salivary Streptococcus mutans levels, maternal sharing, oral hygiene, and feeding attitudes at baseline and at 24-month follow-up period.
Design.  A total of 92 children, aged between 15 to 35 months, comprised the study group. The children's dental examinations were first carried out at baseline, and 56 of them were re-examined 24 months later to determine the changes in dental status. The mothers were also interviewed at each examination based on a prepared questionnaire.
Results.  The prevalence of caries incidence was 45% at 24-month evaluation period among initially caries-free children. The new caries formation was mostly observed on occlusal and aproximal surfaces of maxillary molars (28% and 26%) followed by mesial, distal and buccal surfaces of anterior teeth, respectively. Significant correlations between dental caries formation and maternal sharing, S. mutans levels, and plaque scores were found.
Conclusion.  The results indicated that early S. mutans colonization, high plaque accumulation, and maternal sharing were important factors on a child's caries development.     

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.     

Streptococcus mutans and Streptococcus sanguinis colonization correlated with caries experience in children

The aim of this study was to examine the colonization of Streptococcus mutans and Streptococcus sanguinis in the oral cavity and the association with severe early childhood caries (S-ECC). Saliva and plaque samples were collected from 14 S-ECC children and 8 caries-free (CF) children. All S-ECC children were S. mutans positive; 100% of CF children and 93% of S-ECC children were S. sanguinis positive. The children's caries severity was positively correlated with levels of S. mutans (p < 0.001), total oral streptococci (p < 0.01), total cultivable oral bacteria (p < 0.05), and children's age (p < 0.05). Logistic regression analysis showed that the interaction of S. sanguinis with S. mutans was a significant factor associated with the caries status in children, suggesting that the relative levels of these two microorganisms in the oral cavity play an important role in caries development.     

Association of caries activity with the composition of dental plaque fluid

This study tests the hypothesis that caries activity is associated with lower degrees of saturation with respect to enamel mineral in dental plaque fluid following sucrose exposure. Plaque fluids were obtained from caries-free, caries-positive, and caries-active subjects. Samples were collected before and at 3 and 7 min after a sucrose rinse on consecutive weeks and analyzed for organic acids, inorganic ions, pH, calcium activity, and, in selected samples, total protein. After sucrose, pH values were significantly lower in the caries-active group in comparison with the caries-free and caries-positive groups. Total and free calcium concentrations increased with decreasing pH, with free calcium being about one-third of total calcium. The caries-active group exhibited significantly lower degrees of saturation with respect to enamel mineral, after sucrose, and had significantly higher mutans streptococci levels in plaque than did the caries-free samples. Thus, saturation levels in post-sucrose plaque fluids reflect the cariogenic potential of dental plaque.     

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.     

Quantitative analysis of biofilm bacteria according to different stages of early childhood caries

ObjectiveMonitoring selected key species related to health or disease may facilitate caries risk assessment and discovery of novel ecological preventive and therapeutic approaches. This study aimed at quantifying Actinomyces naeslundii, Bifidobacterium spp., Lactobacillus acidophilus, Lactobacillus casei group, Streptococcus gordonii, Mitis group and Streptococcus mutans by quantitative polymerase chain reaction (qPCR) in dental biofilm from Brazilian children with different stages of early childhood caries (ECC).DesignSeventy-five preschool children were clinically evaluated by ICDAS criteria and divided into groups: caries-free (CF; n = 20), enamel caries lesions (ECL; n = 17) and dentine caries lesions (DCL; n = 38). Plaque samples from all children were collected for detection and quantification of the selected bacteria.ResultsL. acidophilus and L. casei group were absent in almost all plaque samples. No differences in relative proportions of A. naeslundii, Mitis group and S. gordonii were observed in any stage of caries. However, S. mutans and Bifidobacterium spp. were present at higher concentrations in the biofilm of children with DCL (p < 0.001). Multivariate analysis showed that S. mutans and Bifidobacterium spp. were strongly associated with biofilm in children with DCL.ConclusionDifferences were observed in the proportion of acidogenic and aciduric bacteria with dental caries progression. The data indicate that S. mutans and Bifidobacterium spp. in dental biofilm may be involved in some progression processes for ECC.     

Association of maternal-child characteristics as a factor in early childhood caries and salivary bacterial counts

The aim of this study was to investigate the caries-related microorganisms in saliva and the prevalence of Early childhood caries (ECC) in 15- to 35-month-old Turkish children and their associations with the characteristics of the mothers, socioeconomic criteria, and feeding habits of the children. METHODS: Saliva samples of 101 children were studied to determine the numbers of Streptococcus mutans, lactobacilli, and Candida albicans. A questionnaire regarding the characteristics of the mothers, socioeconomic criteria, and feeding habits of the children was carried out before the dental examinations of the mother-child pairs. RESULTS: The regression analyses revealed DMFS scores of the mothers as an impact factor for the children's caries experience. The prolonged usage of feeding bottle with sweetened milk, pacifier use, and maternal sharing were strongly associated with the colonization of S. mutans, lactobacilli, and C. albicans, respectively. A significant correlation was also found between maternal education and S. mutans. CONCLUSION: Data indicated that the mother's DMFS scores, education, and feeding habits were strong risk indicators for the colonization of caries-related micro-organisms and ECC.     

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

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.     

Relationship among microbiological composition and presence of dental plaque, sugar exposure, social factors and different stages of early childhood caries

Objective

This cross-sectional study aimed to investigate the relationship among microbiological composition of dental plaque, sugar exposure and social factors, as well as the presence of visible plaque in preschoolers with different stages of early childhood caries.

Design

A total of 169 children were clinically examined according to the World Health Organisation criteria + early caries lesions and were divided into three groups: caries-free (n = 53), early caries lesions-ECL (n = 56), and cavitated caries lesions-CCL (n = 60). The presence of clinically visible dental plaque on maxillary incisors was recorded. After that, dental plaque from all buccal and lingual smooth surfaces was collected and the number of colony-forming units of mutans streptococci and total microorganism, as well as the presence of lactobacilli was determined. Daily frequency of meals containing sugar was assessed by a diet chart whereas social factors were evaluated by a questionnaire. The data were analysed by chi-square test followed by multiple logistic regressions (α = 0.05, confidence interval = 95%).

Results

High levels of mutans streptococci (OR = 2.28), high total sugar exposure (OR = 5.45) and presence of dental plaque (OR = 2.60) showed significant association with ECL (p < 0.05). High total microorganism count (OR = 5.18), high solid sugar exposure (OR = 2.50) and the presence of lactobacilli (OR = 24.99) revealed significant association with CCL (p < 0.05).

Conclusions

These results support the conclusion that dietary sugar experience influenced the microbiological composition of dental plaque. Moreover, the early stage of caries is highly affected by mutans streptococci and visible dental plaque on maxillary incisors whereas cavities are strongly related to lactobacilli and total microorganism.