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

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

Comparison between different methods for sampling cariogenic microorganisms in persons with exposed root surfaces

The levels of lactobacilli, mutans streptococci and the group of Actinomyces viscosus and Actinomyces naeslundii in a 15-s rinse were compared with the levels of these bacteria in paraffin-stimulated saliva and in pooled plaque from exposed root surfaces. Samples were obtained on 2 occasions from 30 subjects. The levels of lactobacilli, mutans streptococci and Actinomyces spp. in the rinse correlated strongly with the levels in the saliva (r=0.95, r=0.87, r=0.66 respectively). The mean levels of lactobacilli, mutans streptococci and Actinomyces spp. per ml were about 5, 10 and 4 limes higher respectively in the saliva than in the rinse medium. The correlations between the rinse levels and the levels in plaque were O.68, 0.65 and 0.42 but the correlations between saliva and plaque levels were even weaker (0.53, 0.56 and 0.38). The results indicate that a 15-s oral rinse can be as useful as saliva sampling when discriminating between high and low levels of caries-associated microorganisms in root surface plaque. The rinse method has definite advantages compared to saliva sampling in persons with low salivary secretion rate or difficulties to chew.     

Correlation of cariogenic bacteria and dental caries in adults

Many studies suggest that mutans streptococci (MS), Lactobacillus (LB), and salivary buffering capacity are important risk factors for dental caries. However, target populations for most studies were children. In adult patients, the same risk factors affect the number of fillings or prostheses or secondary caries. It is therefore important to investigate these risk factors as predictors of caries in adults. In the present study, we evaluated the oral conditions of adult subjects at private dental offices using bite-wing radiographs. Detection of salivary LB level using Dentocult LB had a statistically significant correlation with the number of flat surface caries and approximal caries (P < 0.001). Detection of salivary MS level using Dentocult MS and salivary buffering capacity did not predict dental caries. Thus, detection of salivary LB level using Dentocult LB may be a useful tool for detecting approximal and secondary caries.     

致龋菌对牙周炎形成影响的动物实验研究

目的探讨龈上菌斑的致龋菌对牙周组织的破坏作用。方法 5～6周龄金黄地鼠20只,雌雄各半,随机分成2组,A组：高蔗糖饮食组;B组：高蔗糖饮食同时接种变形链球菌和粘性放线菌。种菌结束后8周处死,检查下颌第一磨牙牙周的损害情况。结果 B组菌斑指数和牙槽骨吸收值明显大于A组（P〈0.01）,探诊出血比率大于A组（P〉0.05）。组织病理显示B组出现牙石聚积,结合上皮向根方增殖,炎症细胞浸润,炎症表现比A组更显著。结论龈上菌斑中的致龋菌在牙周组织炎症形成中起一定的作用。     

麦芽糖醇口香糖对口腔三种致龋菌的抑制作用

目的:探讨麦芽糖醇口香糖对口腔中3 种致龋菌的抑制效果.方法: 将30 名13～15 岁龋易感儿童随机分为3 组,即麦芽糖醇口香糖组(A组)、木糖醇口香糖组(B组)、空白胶母口香糖组(C组).咀嚼口香糖前后共收集2 次牙菌斑,运用平板法进行牙菌斑中细菌培养计数观察咀嚼口香糖前后3 种致龋菌(变链、乳杆、黏放)数量的变化.结果: 与咀嚼前相比,咀嚼口香糖4 周后A、B、C 3 组变链、乳杆、黏放致龋菌数量均呈下降趋势(P<0.001);与C组相比,咀嚼口香糖4 周后A、B 2 组更能显著降低变链数量(P<0.05);3 组间乳杆菌数量和黏放数量的下降无统计学差异(P>0.05).结论:麦芽糖醇口香糖抑制牙菌斑内变链菌数量较为明显,对乳杆菌、黏放菌的抑制作用则不明显.     

Effect of whitening agents containing carbamide peroxide on cariogenic bacteria

PURPOSE: The purpose of this study was to investigate the in vitro antibacterial effects of three different carbamide peroxide products (Nitewhite, Opalescence, and Proxigel) on cariogenic microorganisms (mutans streptococci [MS] and lactobacilli), and to evaluate the effects of a 10% carbamide peroxide solution (Proxigel) on salivary levels of MS and lactobacilli clinically. MATERIALS AND METHODS: Growth inhibition studies were performed to determine the concentration and exposure time of carbamide peroxide to give total inhibition of recoverable growth of MS and lactobacilli. Paraffin-stimulated saliva samples were collected from subjects before and after 6 weeks of treatment with 10% carbamide peroxide in bleaching trays, and levels of MS and lactobacilli were determined. RESULTS: The growth inhibition studies showed no visible growth of MS or lactobacilli at 24-, 48-, or 72-hour incubation, after a 2-hour exposure to 1% carbamide peroxide. Identical results were obtained with all three carbamide peroxide products. In the clinical study, the mean salivary MS levels, expressed as logarithm colony-forming units per milliliter (CFU/mL), were 5.38 for the pretreatment samples and 5.23 for the post-treatment samples. The differences were not statistically significant (p > .05). However, there was a reduction in logarithm lactobacilli counts from a mean of 4.12 pretreatment to a mean of 2.74 post-treatment. This was statistically significant (p < .05).     

感染根管内产黑色素类杆菌的定植

目的:了解感染根管内产黑色素类杆菌(BPB)的定植情况.方法:采用16S rDNA PCR技术检测5种BPB在牙髓炎、慢性根尖周炎患牙根管内的定植情况.统计学分析5种BPB在感染根管内检出率的差异及菌种间相互关系.结果:BPB在感染根管内总检出率为60%,其中牙髓卟啉单胞菌(Pe)、变黑普氏菌(Pn)、牙龈卟啉单胞菌(Pg)、产黑普氏菌(Pm)、中间普氏菌(Pi)检出率分别为38%、32%、30%、18%、14%.Pe、Pn检出率明显高于Pm、Pi(P<0.05).Pe在慢性根尖周炎组检出率(50%)明显高于牙髓炎组检出率(20%)(P<0.05).Pn、Pg、Pi和Pm在慢性根尖周炎组检出率(43.33%、36.67%、16.67%、16.67%)与牙髓炎组检出率(20%、20%、10%、15%)无明显差异(P>0.05).Pg/Pe、Pg/Pn、Pe/Pn之间存在正相关.结论:BPB是感染根管内的优势菌群,是牙髓炎和慢性根尖周炎共有的致病菌.Pg/Pe、Pg/Pn、Pe/Pn常定植于同一根管.     

薄荷复方煎液对龋病及牙周病致病菌生理活性的影响

目的:研究薄荷复方煎液对龋病及牙周病致病菌产酸及合成细胞外多糖的影响,明确薄荷复方煎液的抗菌机制. 方法:选取血链球菌和牙龈卟啉单胞菌作为实验菌株,研究薄荷复方煎液对口腔细菌产酸及合成水不溶性胞外多糖能力的影响. 结果:薄荷复方煎液使血链球菌和牙龈卟啉单胞菌的产酸量和合成不溶性葡聚糖含量明显减少.结论:薄荷复方煎液对口腔细菌的酸代谢和糖代谢有一定的抑制作用.     

Effect of 2-O-stearoyl glycerol-1,3-bisphosphate on in vitro demineralization of dental root surfaces.

The effect of 2-O-stearoyl glycerol-1,3-bisphosphate (Glydip) on caries lesion formation in root surfaces of sound human third molars was investigated in vitro. For this purpose parts of the root surfaces were treated with Glydip. Adjacent parts of the surfaces were not treated and served as control. Lesions were obtained by demineralization with an acetate buffer of pH 5.0. It was found that Glydip had no inhibiting effect on the rate of lesion formation. Additionally, pretreatments were performed with lauryl sulphate, a chloroform-methanol mixture, an aqueous solution of sodium hypochlorite, and collagenase prior to the treatment with Glydip to enhance the accessibility of the tissue for Glydip. None of these pretreatments or combinations of them revealed an inhibiting effect of Glydip on the rate of caries lesion formation. This result is in contrast to the effect of Glydip on the demineralization of enamel.     

Microbiology of the early colonization of human enamel and root surfaces in vivo

This study describes the predominant early microflora on human teeth on the basis of microbiologic identification of 1742 fresh isolates. The isolates were obtained from four dental students who carried test pieces of enamel and root surface in the oral cavity for 4, 8, 12, and 24 h. During the experimental periods oral hygiene was discontinued. Under equal conditions root surfaces were more heavily colonized than were enamel surfaces. However, the composition of the microbiota was the same. Within the first 24 h the microflora was dominated by streptococci and Gram-positive pleomorphic rods. S. sanguis contributed only 6-18% of the early colonizers whereas S. mitis and S. oralis varied between 24-42% and 1-27% (mean values), respectively. The relative proportion of S. oralis increased significantly within the observation period while the proportion of S. salivarius and arginine-positive S. mitis showed a declining tendency. Actinomyces species adsorbed to the tooth surfaces within the first 4 h but did not increase their relative proportions until after 8-12 h, possibly due to a long doubling time. In one individual, encapsulated bacteria resembling Stomatococcus mucilaginosus were observed among the early colonizers. The time-dependent shifts in the bacterial populations within 24 h corroborate parallel ultrastructural findings.     

老年人桩核冠修复前后龈沟内致龋菌变化的比较研究

目的 研究老年人桩核冠修复前后不同时期根面菌斑中主要致龋菌定植数量变化。方法 以单纯随机法选择下颌第一磨牙无咬合功能的患者30人,将一侧需行桩核冠修复的第一磨牙和对侧健康第一磨牙分为受试牙和对照牙。受试牙预备前、预备后 72 h、预备后 1周及冠修复后 1个月,分别采集受试牙与对照牙根面菌斑,然后进行厌氧培养、分离,通过菌落形态学检查、生化特征及聚合酶链反应（ PCR）对其中变异链球菌、内氏放线菌和黏性放线菌进行鉴定和菌落计数。结果 受试牙变异链球菌预备前、预备后 72 h、预备后 1周、修复后 1个月菌落计数的变化差异有统计学意义（ P<0.05）。受试牙黏性放线菌菌落计数在预备前、预备后 72 h、预备后 1周、修复后 1个月的变化差异有统计学意义（ P<0.05）。受试牙内氏放线菌菌落计数在预备前、预备后 72 h及1周、修复后 1月的变化差异有统计学意义（P<0.05）。结论 变异链球菌、内氏放线菌及黏性放线菌在预备后1周菌落计数增加,修复后1个月菌落计数降低。以上结果提示在牙体预备后初期,应指导患者进行菌斑控制。