茶多酚影响致龋菌在唾液获得性膜粘附的研究

目的：研究茶多酚对致龋菌在唾液获得性膜粘附的影响,进一步探讨茶多酚的防龋机制。方法：采用唾液包被羟磷灰石（Ｓ－ＨＡ）形成实验性膜的体外模式,以变形链球菌和粘性放线菌作为主要致龋菌,用茶多酚分别处理Ｓ－ＨＡ和细菌,观察细菌在Ｓ－ＨＡ粘附的情况。结果：两组实验中,茶多酚溶液浓度为１～４ｍｇ／ｍｌ时都能显著抑制变形链球菌和粘性放线菌在Ｓ－ＨＡ上的粘附,且抑制作用随茶多酚溶液浓度的升高而逐渐增强。结论：茶     

表面活性剂与实验性获得性膜相互作用的体外研究

为了探索表面活性剂影响细菌对牙面粘附的机理，本文比较了５种表面活性剂与实验性获得性膜的相互作用，结果表明，实验用５种表面活性剂中，阴离子表面活性剂ＺｏｎｙｌＦＳＡ使吸附的唾液蛋白量明显增加，而其余４种阳离子表面活性剂能明显地移去吸附的唾液蛋白，本研究结果提示，表面活性剂与实验性获得性膜的相互作用与其所带的电荷有关，表面活性剂对获得性膜的影响是其菌斑的可能机理之一。     

不同品牌正畸用热压膜材料吸水性能的比较

目的通过比较临床上常用的4种品牌的热压膜材料的吸水量,评价其性能在口腔环境下的稳定性。方法选择Erkodur、Biolon、DR和Scheu 4种压膜片,厚度均为1.0 mm。测试并比较4种材料在模拟口腔环境下3周内的吸水量。比较不同品牌热压膜材料吸水量的差异。结果 4种品牌热压膜材料的吸水量随着时间的增加而升高,在最初48h,材料的吸水速度较快,2周后吸水基本饱和。Scheu的吸水量最大(8.78 mg/g),Erkodur最低(8.03mg/g)。浸泡1d后,4种材料的吸水量没有明显差别(P0.05);2周后,Erkodur的吸水量显著低于Scheu和DR(P0.05)。结论 Erkodur膜片具有较低的吸水量,水分对Erkodur膜片性能的影响相对较小。     

表面活性剂对S．sobrinus 6715在实验性获得性膜粘附影响的体外研究

通过细菌对羧磷灰石（ＨＡ）表面形成的实验性获得性膜粘附的实验模式，比较了５种表面活性剂对Ｓ．ｓｏｂｒｉｎｕｓ６７１５粘附的影响。结果表明，所实验的５种ＳＡＡ对Ｓ．ｓｏｂｒｉｎｕｓ６７１５对原位形成的葡聚糖的粘附无明显影响，而阳离子含氟表面活性剂ＺｏｎｙｌＦＳＣ在０．１％～０．２％浓度时对粘附的菌细胞有明显的解吸作用。     

抛光对直接修复用牙色材料粗糙度及表面能的影响

目的 评价表面抛光对3种直接修复用牙色材料粗糙度及表面能的影响,以期为临床提供参考.方法 选用3种直接修复用牙色材料,复合树脂(CR)( Fihek Z350,3M ESPE,America)、玻璃复合体(Giomer)(Beautifil Ⅱ,Shofu,Japan)和树脂改性玻璃离子(RMGIC)(FujiⅡLC,GC,Japan),分别放入预制模具中(8 mm×8 mm×2 mm),材料表面使用聚酯膜覆盖,每种材料制作试件14个,光照固化后,用抛光碟进行序列抛光(灰60μm→紫30μm→绿20 μm→红7μm).抛光前后检测表面粗糙度(Ra)及表面能(γSTOT),并对结果进行统计学分析.结果 抛光前CR和Giomer的Ra[分别为(0.098 ±0.019)、(0.093±0.020) μm]和γSTOT[分别为(31.78 ±2.14)、(32.63±2.12) mN·m-1]均显著低于RMGIC[Ra及γSTOT分别为(0.134±0.019) μm和(40.22±1.05) mN· m-1],P＜0.05.抛光后3种材料的Ra均增大,CR[ (0.141±0.018) μm]＜Giomer[ (0.185 ±0.013) μm]＜RMGIC[(0.494±0.075) μm],3种材料间差异有统计学意义(P＜0.05);3种材料γSTOT均降低,Giomer [(26.60±5.61) mN· m-1] ＜CR[ (29.16±5.73) mN· m-1] ＜RMGIC[ (32.30±3.83) mN· m-1],3种材料间差异有统计学意义(P＜0.05).结论 直接修复用牙色材料抛光后的表面粗糙度及表面能与材料种类密切相关.     

粘性放线菌对牙面粘附机理的研究──Ⅰ．实验性全唾液获得性膜蛋白组份的分离纯化

采用羟基磷灰石柱层析形成实验性获得性膜的体外模型，研究全唾液获得性膜蛋白的组成成份。结合离子交换及分子筛层析分离获得８种获得性膜的蛋白成份。根据层析用谱、等电点、氨基酸组成及免疫扩散分析，其中６种可确定为富脯糖蛋白、淀粉酶、ＳＩｇＡ、酸性富脯蛋白、富酪蛋白及富组蛋白。实验结果表明唾液中的蛋白质选择性吸附到羟基磷灰石上，分离纯化的获得性膜蛋白为筛选促进致龋菌在牙面粘附的唾液蛋白受体提供了直接的研究材料。     

铸造镍铬合金冠桥对唾液中镍元素浓度影响的实验研究

目的：探讨铸造镍铬合金对口腔唾液中镍含量的影响。方法：分别采用镍铬合金和铸造过一次的镍铬合金制作全冠各48颗，分装于12个试样中，即实验Ⅰ和实验Ⅱ组。测定实验Ⅰ和实验Ⅱ组4周，8周镍含量，并与正常人群(对照组)进行比较。结果：1．不同时期实验Ⅰ组与对照组间无显著性差异。2．实验Ⅱ组与对照组间及实验H组4周与8周间均有显著性差异。结论：1．铸造镍铬合金对口腔唾液中镍含量无明显影响，是安全可靠的。2．铸造镍铬合金重复使用增加了镍离子游离出来的可能性。     

Charter刷牙法对桥体下牙槽嵴黏膜健康的影响

目的：评价Charter刷牙法局部口腔卫生维护对Co-Cr合金、Vita95瓷两种材料桥体下牙槽嵴黏膜健康的影响。方法：采用随机分组对照试验，要求实验组每天采用Charter刷牙法对桥体进行局部卫生维护，评价并分析实验组和对照组3个月后桥体下牙槽嵴黏膜炎症状况的差异。结果：实验组的炎症程度明显低于对照组，统计学相差显著。烤瓷和金属材料之间比较，在对照组两者对牙槽黏膜的影响有显著差异。结论：局部口腔卫生维护有利于保持桥体下黏膜的健康，而不同桥体材料对黏膜健康的影响在短期内并不显著。     

唾液神经氨酸苷酶对变链菌附着至获得性膜的影响

用神经氨酸苷酶处理覆盖有获得性膜的羟磷灰石，观察其对变链菌附着的影响，同时测定标本中游离唾液酸的含量。结果表明，用神经氨酸苷酶处理获得性膜后，变链菌附着量显著降低，但标本中游离唾液酶含量无显著变化。研究结果提示，唾液获得性膜可能是介导变链菌附着的受体。     

含氟表面活性剂对变形链球菌和粘性放线菌对实验性唾液膜粘附的影响

许多含氟表面活性剂已显示了明显的控制菌斑作用．本文研究了5种表面活性剂对变链菌JBP和粘性放性菌LY-7对唾液实验性膜粘附的影响．结果表明，5种表面活性剂都不同程度地减少了JBP和LY-7的粘附，有的还对已粘附的细菌有一定的解吸作用．提示表面活性剂控制菌斑的作用与其减少细菌粘附有关．     

The effect of acquired salivary pellicle on the surface free energy and wettability of different denture base materials

OBJECTIVE: The objective of the present study was to evaluate the effect of salivary coating on the wettability and surface free energy of different denture base materials. METHODS: Five acrylic resin and two metallic denture base materials were investigated. Ten specimens of each material (20 x 15x1.5mm) were fabricated and a standardized method was used for polishing the test specimens. Whole unstimulated saliva was collected from a single healthy donor. The wettability properties of the materials were tested before and after organic layer formation. The wetting forces were determined according to the Wilhelmy Plate Technique. Diiodomethane, ethylene glycol and formamide were used as probe liquids.The contact angles, Lifshitz-van der Waals surface energy components, Lewis acid-base surface energy components and total surface energies were calculated using the equations described in the paper. The significance of the differences in the experimentally determined surface energies of different denture materials are calculated by statistical methods. CONCLUSIONS: Light-cured acrylic resin was the most wettable material with a significant basic character. Organic layers decreased the total surface free energies of all materials and at the same time imparted a more basic character. The coatings had a homogenizing effect in terms of the surface free energy components of the denture materials, nevertheless, their adhesive properties were still influenced by the substrate employed.     

Further studies on the composition of the acquired enamel pellicle

Abstract – In the present study pellicle material was collected from human teeth 2, 4 and 6 hr after cleaning. The material obtained was examined by gel filtration, ion exchange chromatography on CM-Sephadex and DEAE-Sephadex with subsequent amino acid analyses of the major anionic component. No major changes were observed to occur either in the overall composition or in the main anionic component of the pellicle during the first 6 hr.     

The influence of surface free energy and surface roughness on early plaque formation

Previous in vivo studies suggested that a high substratum surface free energy (s.f.e.) and an increased surface roughness facilitate the supragingival plaque accumulation. It is the aim of this clinical trial to explore the "relative" effect of a combination of these surface characteristics on plaque growth. 2 strips, one made of fluorethylenepropylene (FEP) and the other made of cellulose acetate (CA) (polymers with surface free energies of 20 and 58 erg/cm2, respectively) were stuck to the labial surface of the central incisors of 16 volunteers. Half the surface of each strip was smooth (Ra +/- 0.1 microns) and the other half was rough (Ra +/- 2.2 microns). The undisturbed plaque formation on these strips was followed over a period of 6 days. The plaque extension at day 3 and 6 was scored planimetrically from color slides. Finally, of 6 subjects samples were taken from the strips as well as from a neighbouring smooth tooth surface (s.f.e. 88 erg/cm2; Ra +/- 0.14 microns). These samples were analysed with a light microscope to score the proportion of coccoid cells, and small, medium, and large rods or fusiform bacteria. At day 3, a significant difference in plaque accumulation was only obtained when a rough surface was compared with a smooth surface. However, at day 6, significantly less plaque was recorded on FEP smooth (19.4%) when compared with CA smooth (39.5%). Between FEP rough (96.8%) and CA rough (98.2%), no significant difference appeared.(ABSTRACT TRUNCATED AT 250 WORDS)     

Protective effect of the in situ formed short-term salivary pellicle

Salivary pellicle, as previously investigated, protects the enamel surface after certain processes of maturation against the influence of acidic agents. The aim of the present study was to investigate the protective effect of the short-term salivary pellicle formed in situ over periods of 3, 60 and 120 min. Six human volunteers used intraoral acrylic splints with bovine enamel samples fixed at the buccal and palatal sites of the maxillary first molars and second premolars. Enamel specimens (n = 252) with and without pellicle were immersed for 60 s in 1.0% citric acid solution under agitation. Knoop surface hardness (KHN) of uneroded polished enamel was measured as a baseline and estimated immediately after erosive treatment reflecting the microhardness loss (DeltaKHN). The amounts of calcium dissolved from the eroded enamel surface were analysed by atomic absorption spectroscopy and scored in mg/l per 10 mm2 of enamel surface area. In addition, the scanning electron microscope was used for the micromorphological examination of the erosive alterations of the enamel surface. The average microhardness loss values after erosion of the enamel samples with buccally/palatally formed pellicle layers were measured as 139.1/144.9 DeltaKHN for 3 min pellicle, 145.9/146.9 DeltaKHN for 60 min pellicle and 141.7/138.6 DeltaKHN for 120 min pellicle. Calcium release values from the specimens with buccal/palatal pellicles were amounted to 15.0/14.9, 16.5/15.9 and 15.3/17.4 mg/l per 10 mm2 for 3, 60 and 120 min-old pellicles, respectively. No significant differences were related to the pellicle formation time and intraoral site (buccal or palatal) in all tested series (ANOVA, P < 0.05). However, significant protection of the enamel surface provided by the pellicle layer was observed on all pellicle-covered surfaces if compared to the non-covered enamel samples (calcium release: 25.6 mg/l per 10 mm2; microhardness loss 187.0 DeltaKHN). These data were in accordance with the morphologic alterations caused by citric acid on the pellicle-covered and pellicle non-covered specimens. It could be concluded that salivary pellicle formed in situ within a period of 3 min offers protection of enamel against citric acid. However, pellicle does not completely inhibit the erosive action of citric acid under the conditions of the present study.     

The effect of red wine in modifying the salivary pellicle and modulating dental erosion kinetics

This study investigated the potential of red wine in modulating dental erosion kinetics in the presence or absence of salivary pellicle. Polished human enamel specimens were used in two conditions; presence or absence of acquired enamel pellicle; and subdivided according to exposure: red wine, orange juice, apple juice, or citric acid. The specimens were incubated in clarified whole human saliva (presence of acquired enamel pellicle) or in a humid chamber (absence of acquired enamel pellicle) for 2 h at 37°C, then in the test substances for 1 min, at 25°C, under shaking. This was repeated four times. Surface hardness was measured initially and after each cycle and surface reflection intensity was measured initially and after all cycles. In the presence of acquired enamel pellicle, red wine caused the least surface hardness loss, followed by orange juice, apple juice, and citric acid. Statistically significantly less surface reflection intensity loss was observed for red wine and orange juice than for apple juice and citric acid. In the absence of acquired enamel pellicle, red wine and orange juice caused less surface hardness loss than apple juice and citric acid. Orange juice showed the least surface reflection intensity loss, followed by red wine, citric acid, and apple juice. The polyphenol composition of these drinks can notably modulate the erosion kinetics.     

Probiotic bacteria affect the composition of salivary pellicle and streptococcal adhesion in vitro

Introduction:  The use of probiotic bacteria is increasing worldwide and at least some of them can transiently colonize the oral cavity. Several studies have shown that probiotic bacteria, which are often thought of in relation only to intestinal health, can also affect the oral ecology, but the mechanisms for this are largely unknown. The aim of this study was to investigate in vitro if the probiotic bacteria used in commercial products affect the protein composition of the salivary pellicle and the adherence of other oral bacteria.
Methods:  Salivary pellicle on hydroxyapatite and the adhesion of two oral streptococci, Streptococcus mutans and Streptococcus gordonii , were used as a model.
Results:  Probiotic bacteria that bound to saliva-coated hydroxyapatite reduced the adhesion of S. mutans but the inhibitory effect on the adherence of S. gordonii was weaker. Salivary pellicle protein composition was modified by all the strains tested. The modifications in the pellicle affected the adherence of S. mutans but not of S. gordonii . Two of the proteins missing from the pellicles made of saliva-treated with the probiotic bacteria were identified as salivary agglutinin gp340 and salivary peroxidase. All bacterial strains bound salivary agglutinin gp340. The ability of the probiotic bacteria to degrade peroxidase was demonstrated with purified bovine lactoperoxidase and two of the probiotic strains.
Conclusion:  This in vitro study showed that probiotic strains used in commercial products may affect the oral ecology by specifically preventing the adherence of other bacteria and by modifying the protein composition of the salivary pellicle.     

Electron microscopic detection of salivary alpha-amylase in the pellicle formed in situ

Immunological and biochemical analyses have shown that alpha-amylase is an essential component of the acquired pellicle. After adsorption, this enzyme might act as a receptor for bacterial adherence. However, data indicating that amylase is bound to the pellicle surface in vivo and thus available for adhering bacteria are rare. Therefore, the present study focused on alpha-amylase within the pellicle formed in situ, using gold-immunolabeling electron microscopic techniques. Pellicles were formed by intra-oral exposure of enamel specimens for 30 and 120 min in six subjects. The results obtained by transmission electron microscopy indicate that amylase was randomly distributed in the pellicle layer without any preferential localization within the pellicle. Thus, salivary alpha-amylase might be considered as an important structural component that is even involved in the early stages of pellicle formation. The findings of field emission in-lens scanning electron microscopy provided evidence that the enzyme is located on the pellicle surface. It could be concluded that alpha-amylase might act as a receptor for bacterial adherence to the pellicle in vivo.     

暂时固定桥对双端固定桥桥体龈端密合度的影响

目的:探讨暂时固定桥对双端固定桥桥体龈端密合度的影响。方法:选择37例拟行后牙三单位双端固定桥修复的患者,按常规步骤制作修复体,选用Luxatemp材料制作暂时固定桥,复诊时检查双端固定桥桥体龈端密合情况,同时针刺法检测并记录缺牙区黏膜厚度。结果:初次复诊时13例双端固定桥桥体龈端不密合,缺牙区黏膜厚度2.215±0.410mm;24例密合,缺牙区黏膜厚度1.918±0.128mm,二者有显著性差异。13例不密合者磨去暂时固定桥桥体部分,观察1周,再次复诊时12例恢复密合。结论:暂时固定桥在牙合力作用下使桥体覆盖区的黏膜发生弹性形变,导致双端固定桥桥体龈端出现间隙。黏膜的变形与黏膜厚度有关,且具有可复性。