异麦芽酮糖醇对变形链球菌乳酸产物及pH值影响的研究

目的 观察异麦芽酮糖醇对变形链球菌产乳酸能力及菌液pH值的影响,为异麦芽酮糖醇在防龋的应用提供实验依据.方法 以异麦芽酮糖醇为实验组,蔗糖、木糖醇为对照组,观察异麦芽酮糖醇、蔗糖、木糖醇对变形链球菌菌液pH值的影响,并利用酶法乳酸试剂盒检测其乳酸产生量的变化.结果 变形链球菌与异麦芽酮糖醇、蔗糖、木糖醇作用后产生的是L-乳酸(左旋乳酸).异麦芽酮糖醇和木糖醇组所产乳酸量和酸度均低于蔗糖组,但异麦芽酮糖醇高于木糖醇组,经两两比较三组所产L-乳酸含量各组之间差异均具有显著性.其菌液pH值之间也具有显著性差异.结论 在异麦芽酮糖醇作用下,变形链球菌所产乳酸量和酸度低于蔗糖.因此,异麦芽酮糖醇是一种低致龋性的糖替代品.     

赤藓糖醇和木糖醇对变异链球菌生长和产酸作用的对比研究

目的对比相同浓度下赤藓糖醇和木糖醇对变异链球菌生长和产酸的影响。方法分别用含0.5%、1%、2%、4%、8%、12%、16%赤藓糖醇和木糖醇的TPY培养基在厌氧条件下培养变异链球菌,分别于0、2、4、6、8、10、12、18、24 h测量液体培养基的光密度值（A值）和pH值,运用SPSS描绘其变化曲线图。结果在0.5%、1%、2%浓度下,赤藓糖醇培养基的A值较木糖醇培养基高,pH值较木糖醇培养基低,说明变异链球菌在含0.5%、1%、2%赤藓糖醇的培养基内的生长和产酸能力明显较相同浓度木糖醇培养基高。在8%、12%、16%浓度下,赤藓糖醇培养基的A值较木糖醇培养基低,pH值较木糖醇培养基高,说明变异链球菌在含8%、12%、16%赤藓糖醇的培养基内的生长和产酸能力明显较相同浓度木糖醇培养基低。结论对比木糖醇,低浓度下赤藓糖醇对变异链球菌生长和产酸的抑制作用较弱,高浓度下赤藓糖醇的抑菌效果更强。     

特异性鸡蛋黄抗体(IgY)对变形链球菌生长及粘附的影响

目的 :研究特异性鸡蛋黄抗体IgY在体外对变形链球菌生长及蔗糖依赖性粘附的影响。 方法 :在培养变形链球菌的培养基中加入不同浓度的IgY ,厌氧培养 18h后 ,涂片 ,显微镜下观察细菌生长形态 ,用分光光度计测定细菌生长状况。含蔗糖培养基中加入不同浓度的IgY ,厌氧培养变形链球菌 ,观察变链菌对试管壁的粘附作用 ,定量计算细菌粘附比例。结果 :加入IgY抗体后 ,变形链球菌的繁殖数量并不发生改变 ,但在生长过程中出现凝集现象 ,且随着IgY浓度的增加凝集程度增加 ,菌链增长 ,对试管壁的粘附性下降。 结论 :IgY不影响细菌的繁殖分裂 ,但可使细菌发生凝集 ,蔗糖依赖性粘附力下降     

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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。     

特异性鸡蛋黄抗体（IgY）对变形链球菌生长粘附的影响

目的：研究特异性鸡蛋黄黄抗体IgY在体外对变形链球菌生长及蔗糖依赖性粘附的影响。方法：在培养变形链球菌的培养基中加入不同浓度的IgY，厌氧培养18h后，涂片，显微镜下观察细菌生长形态，用分光光度计测定细菌生长状况。含蔗糖培养基中加入不同浓度的IgY，厌氧培养变形链球菌，观察变链菌对试管壁的粘附作用，定量计算细菌粘附比例。结果：加入IgY抗体后，变形链球菌的繁殖数量并不发生改变，但在生长过程中出现凝集现象，且随着IgY浓度的增加凝集程度增加，菌链增长，对试管壁的粘附性下降。结论：IgY不影响细菌的繁殖分裂，但可使细菌发生凝集，蔗糖依赖性粘附力下降。     

赤藓糖醇对变异链球菌产酸作用影响的研究

目的研究赤藓糖醇对变异链球菌产酸作用的影响,为赤藓糖醇的防龋应用提供依据。方法观察变异链球菌分别在质量分数1%、2%、4%、8%的赤藓糖醇、木糖醇和蔗糖胰蛋白胨-多价蛋白-酵母提取物（tryptone-polypeptone-yeast extract,TPY）液体培养基中培养24 h后pH值的变化;测定在以上浓度条件下,体外菌斑糖酵解模型产酸液的pH值变化。结果浓度为2%（q=5.63）、4%（q=4.12）、8%（q=5.77）时,变异链球菌在赤藓糖醇中pH值变化均小于蔗糖组,且差异均有统计学意义（P〈0.05）;浓度为8%时,赤藓糖醇组的pH值变化较木糖醇组小,具有统计学意义（q=6.53,P〈0.05）;浓度为2%（q=6.73）、4%（q=6.11）、8%（q=6.98）时,赤藓糖醇对体外菌斑糖酵解模型的产酸pH值大于蔗糖组,具有统计学意义（P〈0.05）;浓度为2%（q=5.46）、4%（q=6.49）、8%（q=6.01）时,赤藓糖醇对体外菌斑糖酵解模型的产酸pH值小于木糖醇组,差异有统计学意义（P〈0.05）。结论一定浓度的赤藓糖醇对变异链球菌产酸代谢和体外菌斑糖酵解模型产酸代谢具有较明显的抑制作用。     

不同生存状态下变形链球菌合成胞外多糖的研究

目的 :比较变形链球菌合成水溶性、水不溶性胞外多糖的能力在生物膜黏附状态与浮游状态下是否存在量的差异及其可能原因。方法 :在多种蔗糖培养浓度和不同培养时间 ,对变形链球菌分别进行静置培养和摇动培养 ,以模拟生物膜黏附状态和浮游状态下生长的变形链球菌 ,蒽酮法测定细菌合成的水溶性胞外多糖和水不溶性胞外多糖的含量。结果 :相同培养时间每种蔗糖浓度条件下 ,生物膜黏附状态下变形链球菌合成的水溶性、水不溶性胞外多糖均要多于浮游状态下的细菌 (P <0 .0 5 ) ,生物膜黏附状态与浮游状态下变形链球菌的数量和合成胞外多糖的量均随着时间的增加而增加 ,不同培养时间同一蔗糖浓度条件下 ,生物膜状态下变形链球菌合成的水溶性、水不溶性胞外多糖也多于浮游状态下的细菌 (P <0 .0 5 )。结论 :生物膜黏附条件下 ,变形链球菌合成水溶性、水不溶性胞外多糖的能力均明显增强 ,这可能是生物膜中的细菌有更强致龋性的原因之一。     

赤藓糖醇对变异链球菌作用机制的实验研究

目的研究赤藓糖醇对变异链球菌细胞壁结构的影响,探讨其抑制变异链球菌生长的机制。方法测定在蔗糖和赤藓糖醇条件下变异链球菌所在的液体培养基中乳酸脱氢酶（LDH）的活性;在扫描电镜下观察变异链球菌表面的形态变化,了解赤藓糖醇对变异链球菌细胞壁的影响。结果在赤藓糖醇组中,变异链球菌所在的液体培养基内LDH的含量和蔗糖组有差别,但差别甚微。扫描电镜显示：在赤藓糖醇组中,变异链球菌的表面形态清晰,没有内容物溢出的迹象。结论赤藓糖醇可能不是通过影响细胞壁结构和功能的完整性而抑制变异链球菌的。     

在不同浓度蔗糖条件下变形链球菌对镍铬合金腐蚀性能的影响

目的 探讨不同浓度的蔗糖条件下,变形链球菌与镍铬合金共同培养后,合金耐蚀性能受到的影响。方法 将镍铬合金制作12个试件,随机分为5.0%蔗糖实验组、5.0%蔗糖培养基对照组、1.0%蔗糖实验组及1.0%蔗糖培养基对照组。8周后分别取出做电化学实验和扫描电镜实验进行耐腐蚀性能的研究。结果 电化学实验结果显示:5.0%蔗糖实验组与1.0%蔗糖实验组相比,自腐蚀电位与自腐蚀电流密度差异均不显著;5.0%蔗糖培养基对照组与1.0%蔗糖培养基对照组相比,自腐蚀电位绝对值减小,自腐蚀电流密度减小(差异均有统计学意义)。扫描电镜实验结果显示:两实验组试件表面无明显差别,与1.0%蔗糖培养基对照组比较,5.0%蔗糖培养基对照组表面出现斑块状花纹,无明显腐蚀痕迹。结论 蔗糖浓度的增加对变形链球菌的生长繁殖有利,但未必会增强变形链球菌对镍铬合金表面腐蚀性的影响。     

赤藓糖醇和木糖醇对变异链球菌黏附的影响

目的对比赤藓糖醇和木糖醇对变异链球菌黏附的影响。方法变异链球菌分别在阴性对照组以及含质量分数2％、4％、6％、8％赤藓糖醇和木糖醇的TPY液体培养基试管内厌氧培养24h,用磷酸缓冲盐溶液（PBS）冲洗含变异链球菌生物膜的试管3次,加入PBS超声震荡。分别收集各组原液并将其稀释至10％,各取50μL分别接种于TPY固体培养基中,厌氧培养48h,行平皿菌落计数并绘制变异链球菌集落生成单位（CFU）计数曲线图。结果赤藓糖醇组和木糖醇组的变异链球菌CFU计数低于阴性对照组,且差异有统计学意义;随着赤藓糖醇和木糖醇质量分数的增加,变异链球菌的CFU计数逐渐降低,且差异有统计学意义。在同一质量分数下,木糖醇组变异链球菌的CFU计数少于赤藓糖醇组。在质量分数为2％和4％时,组间差异无统计学意义;在质量分数为6％和8％时,组间差异有统计学意义。结论赤藓糖醇和木糖醇对变异链球菌的黏附有抑制作用,随其质量分数的增加,抑制效果增强。在质量分数为2％和4％时,赤藓糖醇和木糖醇对变异链球菌黏附的抑制作用没有明显的差异,在质量分数为6％和8％时,木糖醇对变异链球菌黏附抑制效果优于赤藓糖醇。     

Effects of frequent mouthrinses with palatinose and xylitol on dental plaque

The aim was to evaluate the effects of frequent mouthrinses with palatinose, xylitol and a mixture of palatinose and xylitol on plaque pH, plaque formation and cariogenic microorganisms. 15 subjects refrained from toothbrushing during 3 test periods and rinsed 15 × daily for 4 d with 10 nil of: (1) 50% palatinose, (2) 37.5% palatinose+ 12.5% xylitol, or (3) 50% xylitol. A contrast period with no mouthrinses was also carried out. The 4 periods were carried out in a randomized order with a cross–over design. After the 4–day periods, 3 parameters were measured: (1) plaque pH during the first 30 min after a mouthrinse with palatinose, a mixture of palatinose and xylitol or xylitol alone, directly followed by a 2nd rinse with 10% sucrose; (2) number of mutans streptococci and lactobacilli in plaque and saliva; (3) plaque index. The most pronounced pH drop for the sugar substitutes was found when rinsing with 50% palatinose after the palatinose period, and the least pH drop with 50% xylitol after the xylitol period. The sucrose rinse gave similar pH fall after all 4 periods. The microbial data showed no differences between the 4 periods, but the mutans streptococcus counts in saliva decreased after the xylitol period in contrast to the 3 other periods. Regarding the plaque index, xylitol gave lower scores compared to the other 3 periods.     

Effect of xylitol on dental caries and salivary Streptococcus mutans levels among a group of mother-child pairs

Recent researches have focused on xylitol as convenient and effective method to inhibit cariogenic bacteria. The purpose of the present study is to assess the effect of xylitol on plaque accumulation, caries activity and salivary Streptococcus Mutans in a group of Saudi mother-child pairs. MATERIALS AND METHODS: The study sample included 60 mother and child pairs selected on the basis of having high salivary streptococcus mutans levels. The study sample was randomly divided into experimental group (30 pairs) and control group (30 pairs). The experimental group was given xylitol treatment and the controls received fluoride varnish. Both groups were examined to assess caries, plaque and salivary streptococcus mutans levels. Xylitol treatment in the form of chewing gum for mothers and tablets for children was consumed three times/day for three months. All subjects received oral hygiene instructions, dietary counseling and restorative treatment. The results showed that the number of mothers and children with high streptococcus levels in the experimental group decreased to a statistically significant level at the end of the three month period, similarly, the control mothers showed the same trend. A statistically significant decrease in plaque scores was evident only among the children S experimental group. The caries level of children and mothers showed no statistically significant differences between the experimental and control groups. The factors which significantly affected the streptococcus mutans count in children after three months were the child' dmft at baseline the preventive method used and the mother'salivary streptococcus mutans level.     

淀粉与食用糖交互作用的致龋性初探

目的　初步探讨淀粉与蔗糖、高果糖玉米糖浆（high- fructose corn syrup ,HFCS）的交互作用对变形链球菌致龋毒力的影响。方法　变形链球菌UA159培养于质量浓度均为1%的蔗糖、淀粉和HFCS组成的双糖和三糖BHI培养基中,三种单一糖源作为对照,于培养的6个时间点测量每组的pH值,计算ΔpH;96孔微孔板培养20h后采用结晶紫比色法比较7组的粘附力。结果 蔗糖+HFCS和三糖组产酸速度较快,ΔpH明显大于蔗糖+淀粉和淀粉+HFCS组（P<0.05）。4组实验组的粘附性存在统计学差异（P<0.01）,蔗糖+淀粉组的粘附性最强,三糖组的粘附性强于蔗糖+HFCS组,淀粉+HFCS组最弱。结论　淀粉和蔗糖、HFCS间的交互作用会影响变形链球菌产酸、粘附和生物膜的形成,从而导致其致龋性的改变。     

Effect of xylitol chewing gum on salivary Streptococcus mutans in preschool children

Dental caries remains a significant problem for poor children in the United States. One strategy for treating dental caries is to suppress streptococcus mutans, the chief pathogen responsible for the disease. The purpose of this study was to evaluate the effect of xylitol gum in salivary S. mutans levels in preschool children. Sixty-one children were randomly assigned into the xylitol group and the control group. The xylitol group chewed gum sweetened only with xylitol (XyliFresh100%, Hershey Food Corporation, U.S.A.) three times a day for three weeks. S. mutans counts were tested using the Dentocult-SM Strip Mutans-test (Orion Diagnostica, Finland) at baseline and after three weeks. The shift from higher S. mutans scores to lower was greater in the xylitol group than in the control group (p;lt0.05). This study supports the suggestion that chewing xylitol gum may reduce salivary S. mutans levels. Xylitol chewing gum may provide a feasible caries prevention method for preschool children.     

Effect of sorbitol, xylitol, and xylitol/sorbitol chewing gums on dental plaque

The effect of sorbitol (SOR), xylitol (XYL), and the mixture XYL/SOR in chewing gums on dental plaque was studied in three groups of 7 adults (mean age 22.5 years). A fourth group of habitual users of sucrose-containing gums was used as a control. The study involved a 2-week, no-gum period followed by the use of the polyol gums for 2 weeks (10 gums/day in 5 2-gum doses). The daily consumption of XYL and SOR in the XYL and SOR groups was 10.9 g, whereas in the XYL/SOR group, 8.5 and 2.4 g of these polyols were used per day. At the end of the gum period the acidogenic response of the 48-hour plaque was tested using a 10-ml mouthrinse containing the polyols (10% w/v) present in the experimental gums, followed by a 10-ml rinse of 10% (w/v) sucrose solution. The plaque of the subjects who used XYL and XYL/SOR gums showed a significantly better ability to resist pH drops induced by the sucrose rinse than the plaque in the SOR gum group. No changes in resting pH values were observed in the XYL and XYL/SOR groups, whereas the use of SOR gum was associated with significantly lower pH values. The amount of plaque decreased in the XYL/SOR (24.3%) and the XYL (29.4%) groups, but increased in the SOR (48.3%) group, the changes in the SOR group differing significantly from those found in the other groups. The plaque and saliva levels of Streptococcus mutans generally increased in the SOR group, but decreased in groups which used XYL.     

Streptococcus mutans: fructose transport, xylitol resistance, and virulence

Streptococcus mutans, the primary etiological agent of human dental caries, possesses at least two fructose phosphotransferase systems (PTSs), encoded by fruI and fruCD. fruI is also responsible for xylitol transport. We hypothesized that fructose and xylitol transport systems do not affect virulence. Thus, colonization and cariogenicity of fruI(-) and fruCD(-) single and double mutants, their WT (UA159), and xylitol resistance (X(r)) of S. mutans were studied in rats fed a high-sucrose diet. A sucrose phosphorylase (gtfA(-)) mutant and a reference strain (NCTC-10449S) were additional controls. Recoveries of fruI mutant from the teeth were decreased, unlike those for the other strains. The fruCD mutation was associated with a slight loss of cariogenicity on enamel, whereas mutation of fruI was associated with a loss of cariogenicity in dentin. These results also suggest why xylitol inhibition of caries is paradoxically associated with spontaneous emergence of so-called X(r) S. mutans in habitual human xylitol users.