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。     

Efficacy of ozone on survival and permeability of oral microorganisms

In the present study, we examined the effect of ozonated water on oral microorganisms and dental plaque. Almost no microorganisms were detected after being treated with ozonated water (4 mg/l) for 10 s. To estimate the ozonated water-treated Streptococcus mutans, bacterial cells were stained with LIVE/DEAD BacLight Bacterial Viability Kit. Fluorescence microscopic analysis revealed that S. mutans cells were killed instantaneously in ozonated water. Some breakage of ozonated water-treated S. mutans was found by electron microscopy. When the experimental dental plaque was exposed to ozonated water, the number of viable S. mutans remarkably decreased. Ozonated water strongly inhibited the accumulation of experimental dental plaque in vitro. After the dental plaque samples from human subjects were exposed to ozonated water in vitro, almost no viable bacterial cells were detected. These results suggest that ozonated water should be useful in reducing the infections caused by oral microorganisms in dental plaque.     

Effect of fluoride varnish on Streptococcus mutans counts in plaque of caries-free children using Dentocult SM strip mutans test: a randomized controlled triple blind study

Dental caries is one of the most prevalent infectious diseases and although of multifactorial origin, Streptococcus mutans is considered the chief pathogen in its development. Fluoride is one of the most effective agents used for the reduction of dental caries apart from oral hygiene maintenance. AIMS: The aim of this study was to estimate the counts of Streptococcus mutans and to evaluate the effect of Fluor Protector fluoride varnish on these counts in the plaque of caries-free children using Dentocult SM Strip Mutans. MATERIALS AND METHODS: Thirty caries-free subjects were selected for the study based on the information obtained from a questionnaire and were randomly assigned to the control group consisting of ten subjects and the study group consisting of twenty subjects. Plaque samples were collected on the strips from the Dentocult SM kit and after incubation, the presence of Streptococcus mutans was evaluated using the manufacturer's chart. The study group was subjected to a Fluor Protector fluoride varnish application following which the samples were collected again after 24 hours. RESULTS: The average Streptococcus mutans counts in the primary dentition of caries-free children before and after the application of Fluor Protector fluoride varnish were 10(4)-10(5) colony forming units (CFU)/ml and <10(4) CFU/ml respectively. CONCLUSION: The results showed that the study group had a statistically significant reduction in the plaque Streptococcus mutans counts than the control group.     

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.     

Inhibition of acid production in dental plaque bacteria by green tea catechins

The inhibition of acid production from dental plaque and mutans streptococci by epigallocatechin gallate (EGCg), one of the green tea catechins, was examined. The effect of EGCg solution on dental plaque pH was investigated.Subjects rinsed their mouths with 2 mg/ml EGCg solution and then, after 30-min interval, rinsed their mouths with 10% sucrose. Plaque samples were collected at appropriate times and the pH was measured. The pH values of plaque samples from 15 volunteers were significantly higher after treatment with catechin than after treatment with water. EGCg inhibited pH fall when cariogenic bacteria grown in medium with or without sucrose were incubated with sugar. In medium without sucrose, cultured cells were killed time-dependently by EGCg treatment. However, EGCg did not kill cells cultured in medium containing sucrose. Also, EGCg did not kill oral streptococci adhering to a saliva-coated hydroxyapatite disk. EGCg and epicatechin gallate inhibited lactate dehydrogenase activity much more efficiently than epigallocatechin, epicatechin, catechin or gallocatechin. These results suggest that EGCg is effective in reducing acid production in dental plaque and mutans streptococci.     

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.     

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.     

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。     

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     

Detection of mutans streptococci by latex agglutination test and its application as a caries-activity test

The number of mutans streptococci in saliva and dental plaque has been reported to correlate with the incidence of dental caries. This report describes a simple and rapid diagnostic method for the detection of mutans streptococci in dental plaque using latex agglutination (LA) test. Latex particles (0.876 microns, diameter) were sensitized with partially purified antibodies against whole cells of Streptococcus mutans MT8148 (c), MT703R (e) and OMZ175 (f) and Streptococcus sobrinus B13 (d) and 6715 (g). Whole cells of mutans streptococci or dental plaque was extracted with a mixture of 8M sodium nitrite (5 microliters) and 2M acetic acid (5 microliters) for five minutes and neutralized with 2M sodium hydroxide (10 microliters), and the extract and the sensitized latex suspension (20 microliters) were mixed and the grade of agglutination reaction was read macroscopically after ten minutes standing at room temperature. The LA tests could detect 1.0 10ng of purified serotype antigen and 10(5)-10(6) CFU of live cells of mutans streptococci and specifically distinguish not only the mutans streptococci from the other streptococci but also S. mutans from S. sobrinus. However, cross-reactions were still observed among the serotypes c, e and f of S. mutans or between the serotypes d and g of S. sobrinus. Plaque samples were collected from 168 children (2 to 12 years of age) and the 0.1 mg (wet weight) were applied to the LA tests. At the same time, the total number of mutans streptococci in plaque and the serotypes of each isolate were determined. The results of LA reaction correlated significantly with the number of mutans streptococci in plaque (chi-square analysis; p less than 0.0001). The LA tests discriminated between S. mutans and S. sobrinus in dental plaque. It was found that the latex particles sensitized with anti-serotype c and/or e S. mutans antibodies were most effective in demonstrating mutans streptococci, and they were used in the following studies. The results of LA reaction correlated significantly with both the number of decayed tooth surfaces and the number of decayed and filled tooth surfaces. These results suggest that the LA test in mutans streptococci can be useful for the detection of mutans streptococci in dental plaque and also as a caries-activity test at dental clinics.     

Early acquisition of Streptococcus mutans for children

Existing evidence reveals that in Early Oral Infection the main route of transmission of Streptococcus mutans is mother-child saliva contacts and that initial acquisition takes place during a specific period of time denominated "Window of Infectivity" that lapses between 6 and 30 months of the child's life, with a higher risk between 18 and 30 months of age. The aim of the present study was to analyze Early Oral Infection. The levels of Streptococcus mutans in saliva and bacterial plaque in the binomial mother-child 6 to 18 months after childbirth were evaluated. Twenty-four mother-child binomials that attended the University Hospital of Maternity and Neonatology of Córdoba participated in the study. Samples of saliva and dental plaque were taken from mother and child and seeded in selective Agar Mitis Salivarius Bacitracin medium (0.28 mg/ml) and cultured for 48 hours at 37 degrees C and in 5% CO2 to allow for the growth of Streptococcus mutans. The colonies were identified morphologically and biochemically. At 6 months after childbirth: 58.33% of the samples of the mother's saliva were positive, while the presence of the microorganism was not detected in 100% of the samples of the infants' saliva. At 18 months of after childbirth: 79.16% of the samples of saliva and 100% of the samples of the mothers' dental plaque were positive, whereas the samples of saliva and dental plaque of the infants were positive for Streptococcus mutans in 20.83% and 70.83% of the cases respectively. The initial acquisition of Streptococcus mutans would have occurred in 20.8% of the children at the age of 18 months. Eruption of primary molars occurs at this age.     

Presence of mutans streptococci and Candida spp. in dental plaque/dentine of carious teeth and early childhood caries

This study determined the presence of mutans streptococci and Candida spp. in supragingival dental plaque and infected dentine of caries-free children, with early childhood caries and caries. Pooled samples of dental plaque and infected dentine were collected from 56 children aged 1-5 years, which were divided into 3 groups: early childhood caries (ECC); caries and caries-free. Infected dentine was collected in ECC and caries groups to compare the frequency of these microorganisms in the collected sites. The samples were inoculated in SB20 and SA medium, for mutans streptococci and Candida spp., respectively, and incubated at 37 degrees C for 48 h. Colony growth was verified and the identification was performed by biochemical tests and CHROMagar Candida. Fisher's test or chi-square (chi(2)) were applied (p=0.05). The more prevalent species were S. mutans and Candida albicans in ECC (85.4% and 60.4%, respectively), independently of the sample site. S. mutans only was significantly associated with carious teeth, whether in early childhood caries or not. However, the frequency of C. albicans in ECC was higher when compared to caries and caries-free groups. There is a significant association between the presence of C. albicans and early childhood caries.     

Relationships between dietary behaviours,oral hygiene and mutans streptococci in dental plaque of a group of infants in southern England

This report is part of a prospective study on dietary behaviours, feeding practices, oral hygiene and dental health during the first 18 months of life in a cohort of infants living in southern England. In this part of the study the prevalence of mutans streptococci in the plaque of 1-year-old children and its correlation with sociodemographic status, dietary behaviour and oral hygiene practices over the first 12 months of life were studied. Dietary habits, oral hygiene and dental health at 18 months were also studied. The study group comprised 163 infants. At 12 months of age all children had a dental examination and a plaque sample was removed from the labial surfaces of upper incisors for microbiological examination. A further dental examination took place at 18 months of age; no plaque was sampled. Longitudinal dietary information was obtained with a 3-day food diary at 6, 12 and 18 months of age. Parents/carers completed two structured questionnaires on sociodemographic factors, oral hygiene and feeding behaviour over the first 18 months of life when their children were 12- and 18-month-old. No child exhibited dental caries at 12 and 18 months of age; 18 and 25% had visible dental plaque at 12 and 18 months, respectively. Seven children (4%) had detectable mutans streptococci in their plaque at 12 months of age. Children who had started brushing their teeth or who had had their teeth brushed by 12 months of age were less likely to have detectable mutans streptococci in their plaque than those who had not (P=0.02). The amount of mutans streptococci was significantly correlated with the total number of eating/drinking events per day (P<0.001) and bordered on significant correlation with the mean daily frequency of consumption of foods and drinks containing non-milk extrinsic sugars (P=0.05). None of the sociodemographic variables-sex, social class, mother's level of education-were associated with the detection of mutans streptococci in this group of infants. Multiple logistic regression analysis revealed that two variables were independently and positively correlated with the presence of mutans streptococci in the plaque; these were age when tooth brushing started and total eating and drinking events per day.     

Detection of Streptococcus mutans and Streptococcus sobrinus in dental plaque samples from Brazilian preschool children by polymerase chain reaction

The purposes of this study were to detect S. mutans and S. sobrinus by polymerase chain reaction (PCR) amplification, and to relate their presence to the incidence of dental caries in 42 Brazilian preschool children. Dental plaque samples were collected from the cervical margin of all erupted teeth of 5-6 years old children with primary dentition, using a sterile explorer. Examination of the dmft (decayed, missing, filled teeth) index, performed following the World Health Organization (WHO) caries diagnostic criteria, showed a 2.71 score. Prevalence of S. mutans and S. sobrinus was respectively, of 85.7% and 14.3%; no dental plaque sample was either positive or negative for both bacterial species. Children harboring either S. mutans or S. sobrinus presented the same caries prevalence. PCR showed good discriminative ability for differentiation between these species, and suggested that it is a technique suitable for epidemiological studies on mutans streptococci.     

In vitro acidogenic potential and mutans streptococci of human smooth-surface plaque associated with initial caries lesions and sound enamel.

Samples of human dental plaque were pooled from several "white spot" smooth tooth surface areas as well as from several clinically-sound tooth surface areas in each of 12 caries-positive college students. Each of the two samples from each subject was used for the determination of: (1) pH-lowering potential in vitro involving dispersed plaque suspensions, excess glucose supply, and a 60-minute test, and (2) the proportions of mutans streptococci and lactobacilli. When all subjects were considered, plaques from "white spot" areas, as compared with samples from sound surface areas, were characterized by significantly higher proportions of mutans streptococci, a lower starting ("resting") pH, a faster rate of pH drop between pH 6.0 and 5.0, and a lower minimum pH of the suspension; the lactobacillus proportions were generally very low in both types of plaques. For individual subjects, however, the proportions of mutans streptococci in plaque associated with "white spot" areas showed a wide range (0.001-10.0%), and samples with high as well as low levels of these micro-organisms could exhibit a high rate of pH drop and a low pH minimum. This suggests that, besides mutans streptococci and lactobacilli, other bacteria capable of acidogenesis at a low pH may contribute to the high pH-lowering potential exhibited by many plaques.     

Detection of oral bacteria in cardiovascular specimens

Background/aims:  Oral bacteria, including cariogenic and periodontal pathogens, are thought to be etiological factors in the development of cardiovascular diseases. To define this relationship, we analyzed the distribution of oral bacterial species in cardiovascular specimens.
Method:  Following acceptance into the study, 203 consecutive patients were analyzed, from whom 82 aortic valve specimens, 35 mitral valve specimens, and 86 aortic aneurysmal wall specimens, of which 16 contained aneurysmal thrombus tissues, were obtained. In addition, a total of 58 dental plaque specimens were collected from the same group of patients who underwent heart valve replacement or removal of aortic aneurysms. Bacterial DNA was extracted from both cardiovascular tissues and dental plaque in those cases and then species-specific polymerase chain reaction assays were used to analyze the occurrences of six oral streptococcal and six periodontal bacterial species.
Results:  Streptococcus mutans was the most frequently detected species in the cardiovascular specimens, followed by Aggregatibacter actinomycetemcomitans . As for dental plaque specimens from patients who underwent cardiovascular operations, most of the tested periodontitis-related species as well as oral streptococci were detected at high frequencies. Furthermore, the positive rate of S. mutans in cardiovascular specimens from patients whose dental plaque specimens were also positive for S. mutans was 78%, which was significantly higher than any other tested species when the same analysis was performed.
Conclusion:  Our results suggest that specific oral bacterial species, such as S. mutans and A. actinomycetemcomitans , are related to bacteremia and may be etiologic factors for the development of cardiovascular diseases.     

Relationship between dental plaque indices and bacteria in dental plaque and those in saliva

A variety of indices has been developed for the quantitation of dental plaque. The aim of this study was to determine the correlation between the L?e plaque index and the number of bacteria on the same tooth. Furthermore, the effect of plaque accumulation on the salivary counts of some dental plaque organisms was estimated. Twenty volunteers were asked to abstain from all oral hygiene for a one-week period. Clinical indices and bacteriological samples were taken at the start and at the end of the experimental period. After an interval of seven days, the experiment was repeated. The relationship between the L?e plaque index and the total bacterial counts on the same area of the tooth was found to be highly significant. After seven days without oral hygiene, the total counts and the Actinomyces viscosus/naeslundii and Streptococcus sanguis counts in dental plaque had increased by approximately two log units, while the Streptococcus mutans counts had increased by more than one log unit. The large increase in the number of bacteria on the teeth was reflected in the salivary counts of the Actinomyces species, but not in the S. sanguis or S. mutans counts. This was due to differences in ecological habitats of these species in the mouth. Highly significant correlations were found between the S. mutans level in dental plaque and the salivary level, and between the S. mutans counts of the subjects in the first and second trials of the experiment.     

Latex agglutination test for detection of mutans streptococci in relation to dental caries in children.

A simple and rapid system based on a latex agglutination (LA) reaction was devised for the detection of mutans streptococci in dental plaque. Latex particles were sensitized with antibodies against whole cells of Streptococcus mutans strains MT8148 (serotype c), MT703R (e) and OMZ175 (f) and Strep. sobrinus strains B13 (d) and 6715 (g). These sensitized particles were agglutinated within a few minutes after addition of 1.0-10 ng serotype-specific antigen from the homologous organisms or the nitrous acid extract of whole cells at 10(5)-10(6) c.f.u. The LA test specifically differentiated not only mutans streptococci from the other oral streptococci but also Strep. sobrinus from Strep. mutans. The LA test was also applicable to extracts of plaque from 206 human subjects who harboured mutans streptococci. In clinical trials, the outcome of the LA test correlated significantly with the number of mutans streptococci found in plaque (p less than 0.0001), which was quantified by the selective cultivation of mutans streptococci. Furthermore, the LA test discriminated between Strep. mutans and Strep. sobrinus from human dental plaque. The sensitivity and the specificity of the LA test for detection of mutans streptococci were 78.9 and 100%. The degree of reactivity in the LA test correlated significantly with the number of decayed tooth surfaces (p less than 0.0001) and decayed and filled tooth surfaces (p less than 0.0001). These results suggest that the LA test could be useful clinically for the detection of mutans streptococci in dental plaque as well as serving as a caries-activity test.     

Genotypes of Streptococcus mutans in saliva versus dental plaque

OBJECTIVE: The aim of this study was to investigate whether genotypes of Streptococcus mutans strain can be detected as effectively in saliva samples as in plaque samples from buccal surfaces and occlusal surface fissures of permanent first molars. DESIGN: The study included 20 school children aged 6-7 years who were positive for mutans streptococci. Samples of stimulated saliva and of dental plaque on buccal surfaces and occlusal surface fissures of permanent first molars were collected. Samples were cultivated in MSB agar. Up to nine isolates compatible with mutans streptococci were obtained and identified by means of biochemical tests. All isolates identified as S. mutans were genotyped by arbitrarily primed polymerase chain reaction. RESULTS: A total of 28 genotypes of S. mutans were isolated: 23 in saliva samples, 23 in buccal surface plaque samples, and 16 in plaque samples from occlusal surface fissures. CONCLUSIONS: Although, saliva sampling did not reveal all genotypes isolated, it was equally as effective as plaque sampling from the buccal surfaces of permanent first molars, and more effective than plaque sampling from fissures on their occlusal surfaces.     

Mutans streptococci in margins of fillings and crowns.

A significant correlation was found between the number of mutans streptococci in saliva and the proportional distribution of these microorganisms in pooled plaque from the margins of all restorations. At high salivary numbers there was a tendency towards a higher porportion of mutans streptococci in plaque from the margins of separate restorations. At low and medium salivary numbers, plaque samples could, however, contain greater than 10 per cent mutans streptococci and even less than 1 per cent was found in plaque from margins of restorations at high salivary numbers. The reproducibility of the plaque sampling method was good. Plaque material collected on different occasions from the same margins did not vary significantly in terms of proportions of mutans streptococci. The numbers of mutants streptococci in plaque samples from different restorations of the same kind collected on the same occasion in the same mouth could, however, show a considerable variation. The observations made in this study, indicate that a low salivary number of mutans streptococci does not exclude a high proportion of these microorganisms in plaque from the margins of separate restorations. This has to be considered when efforts are made to reduce the risk of recurrent decay.