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.     

Biofilm growth of Lactobacillus species is promoted by Actinomyces species and Streptococcus mutans

The ability of oral bacteria to integrate within a biofilm is pivotal to their survival. A dependence on the amount of biofilm growth by noncoaggregating Lactobacillus rhamnosus and Lactobacillus plantarum on coculture with Actinomyces naeslundii, Actinomyces gerencseriae, Streptococcus mutans and Veillonella parvula was investigated using an artificial-mouth culture system. Biofilm formation by the lactobacilli in mono-culture was poor. In coculture with Actinomyces species the amount of L. rhamnosus increased 7-20 times and L. plantarum 4-7 times compared to its mono-culture biofilm. S. mutans also promoted substantial biofilm growth of lactobacilli but V. parvula had no effect. We conclude that these Actinomyces species promoted growth of key Lactobacillus species in a biofilm, as did S. mutans to a smaller extent, and that the ability of individual bacteria to form mono-culture biofilms is not necessarily an indicator of their survival and pathogenic potential in a complex multispecies biofilm community.     

正畸粘结剂添加金属镧对变形链球菌抑制作用的研究

目的明确正畸粘结剂添加金属镧后,对变形链球菌生长的抑制作用,并检测其抑制能力的大小。方法实验分3组,阴性对照组用复合树脂粘结剂（compositeresin）、实验组用含5%氯化镧复合树脂粘结剂、阳性对照组用GCFujiOrtho树脂改良型玻璃离子粘固剂,每组10个样本。分别将3组粘结剂样本放入变形链球菌悬液中,厌氧菌培养48h,酶标仪测量菌悬液OD值。结果 3组样本变链菌液OD均值从大到小依次为复合树脂粘结剂组、含5%氯化镧复合树脂粘结剂组、GCFujiOrtho树脂改良型玻璃离子粘固剂组,其组间两两比较,均有显著性差异（P〈0.01）。结论含5%氯化镧复合树脂粘结剂具有明显的抑制变形链球菌生长的作用。     

Current-induced effects on growth and adhesion properties of Streptococcus mutans in vitro

Abstract – Current-induced effects on the growth and adhesion of Streptococcus mutans were studied. The spontaneous currents formed between gold-amalgam pairs showed starting current peaks of approximately 200 μA followed by constant currents of approximately 15 μA. The presence of the gold-amalgam pair had no effect on the growth of S. mutans , which was unaffected even when constant potentials of 1000 mV and 2000 mV were used to produce extreme experimental conditions. Three volts or more was needed to inhibit the growth of S. mutans . Organic acids produced by S. mutans during growth had also little or no effect on the magnitudes of the spontaneous currents formed between the gold-amalgam pairs. Adhesion of S. mutans , grown with or without added sucrose, appeared unaffected by spontaneous currents induced by the metal combinations.     

Presence of Streptococcus mutans and lactobacilli in saliva and on enamel, glass ionomer cement, and composite resin surfaces

Abstract— The quantity of S. mutans , total streptococci, and lactobacilli on sound enamel surfaces and 1-yr-old glass ionomer cement and composite resin fillings with the cervical margins placed subgingivally was compared intraindividually. The amount of bacteria was compared to their number in saliva. The evaluation was done in a cross sectional study, where the patients continued to use their customary oral hygiene procedures and during a 14-day period of experimental plaque formation. The number of lactobacilli and S. mutans recovered from the test surfaces indicated that the critical salivary concentrations necessary for the isolation of S. mutans and lactobacilli from glass ionomer cement and composite resin surfaces are the same as for the enamel surfaces. The fluoride levels in plaque adjacent to glass ionomer cement will not become high enough to inhibit the accumulation of the investigated bacteria.     

Effect of a bacteriocin-producing strain of Streptococcus sobrinus on infection and establishment of Streptococcus mutans on tooth surfaces in rats

The effect of bacteriocin produced by Streptococcus sobrinus MT6223 on infection and establishment of Streptococcus mutans MT6222 was studied in specific pathogen-free rats. These strains were isolated from a carious lesion of a single subject. S. mutans MT6222 was found to be susceptible to the growth inhibitory action of S. sobrinus MT6223. When simultaneously inoculated into the oral cavity of rats, even a small inoculum (10(5) CFU) of S. sobrinus MT6223 completely inhibited colonization of S. mutans MT6222 on the tooth surface. Also, S. sobrinus MT6223 eliminated S. mutans MT6222 when MT6223 (10(8) CFU) was inoculated 2 days after the inoculation of 10(8) CFU cells of MT6222. Similar results were obtained in dental plaque samples from the tooth surface and the fissures of the upper molars at the end of the experiment. However, when S. sobrinus MT6223 (10(8) CFU) was inoculated 2 weeks after the inoculation of S. mutans MT6222 (10(8) CFU), MT6223 coexisted with MT6222. However, the plaque samples showed that MT6223 inhibited the establishment of MT6222 on smooth surfaces, but not in fissures. In addition, MT6223 protected against subsequent infection with MT6222. However, a nonbacteriocinogenic mutant of S. sobrinus MT6223 did not inhibit the infection and establishment of S. mutans MT6222.     

银汞合金抑制变链菌生长的体外研究

目的：了解银汞合金的抗菌能力。方法：用体外试管法比较了不同配方和不同重量的银汞合金对儿童口腔新分离的变链菌株生长的影响。结果：各银汞合金组对变链菌的匀有一定的抑制作用,与对照组相比,差异均有显著性。结论：银汞合金有一定的抗菌性能。     

树脂充填前后唾液中变异链球菌的变化

目的 观察使用树脂进行龋齿治疗前后唾液中变异链球菌数量的变化.方法 招募志愿者20名,对其口腔内所有龋齿去净龋坏组织后使用不含氟树脂材料进行充填,分别收集充填前及充填后第1、2、3、4周的非刺激性唾液样本,使用轻唾-杆菌肽琼脂培养基厌氧培养48 h后检测变异链球菌数量,比较其在龋齿充填治疗前后的变化.结果 龋齿行树脂材料充填后1周唾液中变异链球菌数量较充填前下降明显(P＜0.05),充填后2、3、4周较充填前无明显变化(P＞0.05).结论 对患龋个体进行龋齿备洞后的树脂充填能在短期内降低唾液中变异链球菌的含量,但随时间推移,唾液中变异链球菌数量会逐渐恢复到治疗前的状态.单纯依靠龋齿充填治疗并不能改变唾液中变异链球菌的数量.     

Adherence of Streptococcus mutans to various restorative materials in a continuous flow system

A continuous flow system was developed to evaluate the adhesion of Streptococcus mutans ATCC 25175 to filling materials (Ariston, Tetric, Dyract, Compoglass, Vitremer, Aqua Ionofil, Ketac Fil, amalgam, Galloy and ceramics as controls). Streptococcus mutans was added to saliva-coated test specimens, and a nutrient broth permanently supplied over a time period of 48 h and then the weight of plaque, the number and viability of the bacteria adhering to the materials were determined. The weights of artificial plaque on all filling materials tested were higher than those on ceramics, the highest values were measured on the glass-ionomers. The amount of plaque correlates with the surface roughness, whereas there was no correlation of the surface roughness with the number of colony-forming units (CFU) of S. mutans. The CFU of adhering S. mutans also depends on the viability of the bacteria. The plaque on Ketac Fil contained a high number of viable bacteria. The fluorides of glass-ionomers do not efficiently prevent the attachment and the viability of S. mutans.     

Effect of chlorhexidine on the relative proportions of Streptococcus mutans and Streptococcus sanguis in hamster plaque

abstract — The effect of chlorhexidine on the proportions of Streptococcus mutans and Streptococcus sanguis in plaque was studied in hamsters fed a diet containing 28% sucrose. In animals given chlorhexidine in their drinking water for 10 d a decrease in the population of S. mutans and an increase of S. sanguis occurred in the plaque. Following the removal of chlorhexidine the population of S. mutans increased again in the presence of sucrose and the number of S. sanguis returned to initial values. When animals were given a sucrose-free diet the low proportion of S. mutans observed following the short-term chlorhexidine period persisted. These data indicate that there is an inverse relationship between the number of S. sanguis and S. mutans in plaque and that the sensitivity in vivo of S. mutans to chlorhexidine can be used to suppress the population of S. mutans with a concomitant rise in the proportion of S. sanguis .     

Reasons for restorative therapy and the longevity of restorations in adults

The aim of this study was to obtain information on the restorative dental care of adults in Finland. A random sample of private dentists was drawn from the register, and in spring 2000 they were sent a questionnaire requesting them to record information for each restoration placed during one ordinary working day. A total of 800 dentists were contacted and 548 responded. The dentists reported placement of 3,455 restorations. Of these, 5% were Class I, 36% were Class II, 13% were Class III, 9% were Class IV, 21% were Class V, and 16% were extensive restorations including 4 or more surfaces. Overall, composite resin was the most common restorative material, and it was used in 79% of the restorations, whereas amalgam was used in 5%, compomers in 4%, and glass ionomers (either conventional or resin‐modified) in 7% of cases. In 5% of the cases, the tooth was restored with indirect restorative methods, using either gold or ceramic materials. Of the treatments, 65% were replacements of previous restorations. Secondary caries was the most common reason for replacement (36%, 52%, and 41% for composite, glass ionomer, and amalgam, respectively). Other common reasons were fractures of the tooth or restoration (23%, 11%, and 22% for composite, glass ionomer, and amalgam, respectively) and lost composite restorations (16%). The median age of failed restorations was 15 years for amalgam, 6 years for composite, and 7 years for conventional glass ionomer. Although the longevity of tooth coloured restorations was shorter than that of amalgam, comparisons with our previous studies indicate improved survival periods for tooth coloured materials.     

甘草酸对酸性环境中变异链球菌生长影响的体外研究

目的研究酸性环境中甘草酸对体外培养变异链球菌生长的影响。方法在pH 7.0、pH 5.5和pH 4.0环境中培养变异链球菌,同时在培养基中加入3种浓度（0.78、1.57、3.13 mg·mL-1）的甘草酸,37 ℃下厌氧培养24 h后,测定各组的菌落计数和菌悬液吸光度值,分别以阴性对照组和pH 7.0组细菌生存率为对照,计算各组细菌的生存率。结果以阴性对照组为对照,0.78、1.57和3.13 mg·mL-1甘草酸组在pH 5.5环境时细菌生存率为60.96%、60.27%和45.58%,在pH 4.0时细菌生存率为68.75%、53.12%和45.83%。以pH 7.0组为对照,0.78、1.57和3.13 mg·mL-1甘草酸组在pH 5.5和pH 4.0时细菌生存率分别为52.25%和39.05%、74.39%和43.11%、86.38%和55.30%。结论在酸性环境中,甘草酸能够抑制体外变异链球菌的生长,环境酸度降低可使甘草酸的抑菌作用增强。     

Prevalence of dental caries and Streptococcus mutans in Meo of Northern Thailand

The prevalence of dental caries was studied in 505 Meo, a minority of Northern Thailand, using the DMFT index. Plaque material from all patients was examined qualitatively for S. mutans. The DMFT (dmft) index score ranged between 1.69 and 7.06 with a mean of 2.17 +/- 3.24 for men and 3.45 +/- 3.72 for women. There was a statistical difference in caries prevalence between males and females (P less than 0.05). There was no statistical correlation between miang chewing and caries prevalence. Fluoride concentration of water samples was between 0.043 and 0.077 ppm F-. Of 505 plaque samples, 13.3% were positive for S. mutans, mostly of biotype I. Compared to other Northern Thai hill tribes and the Thai rural population, the Meo appear to have a higher dental caries prevalence rate.     

Antineoplastic agents inhibit the growth of Streptococcus mutans and Streptococcus sanguis in vitro

The effect of methotrexate (MTX) and doxorubicin on the growth, metabolism and ultrastructure of Streptococcus mutans and Streptococcus sanguis was studied in vitro. Both anticancer drugs exerted an inhibitory effect on the oral streptococci. MTX was more inhibitory than doxorubicin. The minimum inhibitory concentrations (MICs) of MTX to S. mutans were 0.25-2.5 micrograms/ml and that of doxorubicin 0.2 mg/ml. The MICs of MTX and doxorubicin to S. sanguis were 0.025 micrograms/ml and 2.0-0.02 mg/ml, respectively. When saliva samples of patients with malignant tumors receiving various doses of MTX were analyzed, MTX was found to be secreted into the oral cavity at concentrations ranging from 0.014 to 4.486 micrograms/ml. The saliva of these patients was also found to inhibit the growth of S. mutans, and the inhibition zones were in accordance with the MIC values observed. The results suggest that anticancer therapy must be taken into account when the salivary microbiological findings of cancer patients are interpreted.     

姜黄素对变形链球菌UA159生长、粘附的体外实验研究

目的：探索姜黄素对变形链球菌UA159的抗菌能力及姜黄素对变形链球菌UAl59生物膜形成的影响。方法：微量肉汤稀释法检测姜黄素对变形链球菌的最低抑菌浓度（MIC）。分光光度计分析在抑菌浓度范围内姜黄素对变形链球菌生物膜形成的变化。结果：MIC法测得的姜黄素对变形链球菌的抑菌浓度为128wM,而15μM姜黄素即可显示出抑制变形链球菌生物膜形成的特性,且随着姜黄素浓度增加,抑制能力加强。结论：姜黄素具有抑制变形链球菌生物膜形成的特性,且该抑制能力不是建立在抑制变形链球菌生长基础上的。姜黄素可能成为龋病防治的新试剂。     

Prevalence of Streptococcus mutans with different colonial morphologies in human plaque and saliva

Abstract – Plaque and saliva samples were obtained twice from 58 children at an interval of 1 year and examined for the prevalence of Streptococcus mutans on Mitis salivarius (MS) and Mitis salivarius bacitracin (MSB) agar. Two types of S. mutans colonies with different colonial morphologies were seen on both media. They were serologically identified as serotypes c/e/f and d/g respectively. The first type, morphogroup c/e/f, had the typical "frosted-glass" appearance. It was the most prevalent and was found in 97% of the children. The second type, morphogroup d/g, had a creamy marzipan consistency with a dull, granular surface, gray to brown in color and often with some liquid around or on top of the colony. Group d/g was detected in 21 children (36%) and then together with colonies of group c/e/f. Children infected with single or multiple morphogroups of S. mutans generally harbored the same groups 1 year later. There was a significant positive correlation between the proportion of S. mutans in plaque and their numbers in saliva.     

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目的研究麦芽糖醇对变形链球菌生长和产酸的影响。方法用含2.5%麦芽糖醇（麦芽糖醇组）、木糖醇（木糖醇组）、蔗糖（蔗糖组,作为阳性对照）的TYE液体培养基以及空白TYE液体培养基（阴性对照组）,厌氧条件下培养变形链球菌,测定在不同时间段各液体培养基的光密度（OD）值和pH值。实验结果采用SPSS13.0统计软件进行数据的输入和分析。结果变形链球菌在麦芽糖醇、木糖醇和空白TYE液体培养基内的生长和产酸受到抑制,而在蔗糖组的生长和产酸非常显著。结论麦芽糖醇可以抑制变形链球菌的生长和产酸,可作为一种理想的防龋甜味剂。     

Effect of a fluoride-containing varnish on Streptococcus mutans in plaque and saliva

Abstract – The effect of topical application of a fluoride-containing varnish, Duraphat®, on the level of Streptococcus mutans in saliva and in dental plaque was investigated in schoolchildren. Samples of saliva and pooled buccal plaque were taken before varnish application and 4, 10 and 21 d after treatment. Fluoride varnish treatment with or without a preceding dental prophylaxis had no significant effect on the plaque and salivary levels of S. mutans. The findings suggest that the caries-reducing effect of fluoride varnish cannot be explained by an alteration of the incidence of 5. mutans in dental plaque or in saliva.     

The influence of 30-day-old Streptococcus mutans biofilm on the surface of esthetic restorative materials--an in vitro study

OBJECTIVE: To evaluate the effects of Streptococcus mutans biofilm/restorative materials interaction on surface roughness, hardness and morphology of materials tested. METHODS: Empress 2 (E2), Filtek Supreme (FS), Vitremer (V) and Ketac Molar Easymix (KM) were tested. Twenty-five disks of each material were made and divided into three storage groups: (1) 100% relative humidity (n=5); (2) growth medium (BHI and 1% sucrose) (n=5); (3) S. mutans biofilm-growth medium (n=15). Before storage, hardness measurements were immediately obtained from group 1 specimens. After 30 days of storage, the specimens were cleaned in order to obtain the surface roughness and hardness values, besides morphology analysis by scanning electron microscopy. RESULTS: The surface roughness and hardness values obtained from E2 and FS specimens did not present statistically significant differences among the groups 1, 2 and 3 and between immediate and 30-day-old specimens of each material. However, group 3 specimens of V and KM showed statistically significant higher surface roughness means than other groups. Group 1 specimens of V and KM also showed higher hardness values than the immediate values. Group 3 specimens of V presented decreased hardness values compared with other groups. The scanning electron micrographs showed an increase in surface degradation from group 1 to group 3 for FS, V and KM. CONCLUSIONS: Thirty-day-old biofilm promotes a negative effect on the surface morphology of FS, V and KM, on the surface roughness of V and KM and on the hardness of V.     

不同pH对变异链球菌体外生物膜形成的影响

目的：了解变异链球菌临床株体外生物膜形成规律以及不同pH对生物膜形成的影响。方法：采用微孔板培养,染色、分光光度测定法（A630）绘制体外不同pH条件下（pH=7.0～5.0）593号、18号菌株以及变异链球菌标准株（ATCC25175）的生物膜生长曲线。结果：体外变异链球菌各株在pH=5.0时均不能形成生物膜;pH=7.0时细菌生物膜形成表现为缓慢的非线性生长,12～24h生物膜开始成熟,24～36h出现一相对的生长停滞期;pH=5.0时对已形成12h的变链菌生物膜生长有明显的抑制作用,但经历12h的酸休克后各菌株的生物膜均能恢复生长。结论：变异链球菌在体外pH=7.0时于12～24h形成稳定的生物膜,该生物膜能抵抗一定程度的酸（pH=5.0）攻击,而浮游状态的细菌则不能。