茶浸出液对牙釉质抗酸性的影响

目的探讨茶浸出液对牙釉质抗酸性的影响。方法将30个牙釉质块随机分为茶浸出液组、氟化钠组及去离子水组,采用间断性浸泡的方法处理牙釉质块后浸泡在脱矿液中,测定脱矿液中钙、磷含量的变化。结果茶浸出液组、氟化钠组脱矿液中的钙磷溶出量少于对照组,差异有统计学意义(P<0.05),茶浸出液组与氟化钠组的钙磷溶出量差异有统计学意义(P<0.05)。结论茶浸出液及氟化物均可抑制牙釉质钙磷溶出,茶浸出液对牙釉质有较强的抗酸性。     

蛋白水解酶在牙釉质脱矿中的作用

本文报道用木瓜蛋白酶、胶原酶和胰蛋白酶,处理活体人牙,用木瓜蛋白酶和胰蛋白酶处理离体人牙,结果这些酶对有机酸对牙釉质的脱矿作用无明显的影响,但木瓜蛋白酶和胰蛋白酶对人牙釉质内的蛋白质有溶解作用。作者认为,即使牙菌斑内有溶解牙釉质内蛋白质的物质存在,但对牙釉质的脱矿却无明显影响。     

两种脱矿体系制备人工龋损的病理学比较

目的评价两种不同脱矿体系在人牙釉质与牛牙釉质形成人工龋样损害的情况,确定模拟早期龋实验研究的脱矿系统。方法两种脱矿体系：部分饱和酸缓冲溶液和酸性凝胶溶液,分别在人牙釉质与牛牙釉质制备人工早期釉质龋损,采用偏振光显微镜和扫描电子显微镜观察实验人工龋的组织病理学变化。结果部分饱和的酸缓冲体系制备的人工龋损都具有完整的表层和表层下脱矿,牛牙釉质除了脱矿深度大于人牙釉质外,其它病理学特点都类似于人牙釉质,与早期自然龋损相似。而凝胶液脱矿体系形成的人工龋损不管是人牙还是牛牙都没有明显的表层结构,实验牙表面多出现被腐蚀或溶解。结论部分饱和的酸缓冲液脱矿系统形成的人工龋损病理学变化更接近于自然龋;与人牙具有相似化学组成的牛牙很适合代替人牙来检测脱矿和再矿化的效果。     

茶水提液对早期牙釉质龋再矿化作用的研究

目的探讨茶水提物对早期牙釉质龋的再矿化作用。方法 30个牙釉质块随机分为茶水提液组、氟化钠组及去离子水组,建立人工龋模型后分别进入pH循环实验。肉眼观察牙釉质表面人工龋形成情况。采用显微硬度计测定各组标本脱矿前、脱矿后、pH循环后的釉质表面显微硬度值。结果茶水提液组、氟化钠组及去离子水组脱矿后可见开窗区牙釉质呈白垩色。再矿化实验后,各组表面显微硬度均较脱矿后增加(P<0.01);茶水提液组及氟化钠组表面显微硬度高于去离子水组(P<0.01);茶水提液组表面显微硬度高于氟化钠组(P<0.01)。结论茶水提液具有促早期人工釉质龋再矿化的作用。     

菌斑液对釉质脱矿和表面超微结构影响的体外研究

目的观察人工菌斑液不同矿物质饱和度(DSEN,DSFA)对釉质表面下脱矿量的变化及其对表面超微结构的影响.方法以去离子水作为空白对照组,而以不同DSEN(0.1～0.5)组成的人工菌斑液为实验组,分别对6组釉质磨片连续脱矿96 h后,以激光共聚焦显微镜定量评价各组釉质块脱矿差异,以扫描电镜(×5 000)观察釉质表面超微结构的变化.结果仅在DSEN(0.1～0.3)组发生了典型的釉质表面下脱矿,并且随着DSEN的升高,釉质脱矿量显著下降(P<0.01),表层微孔数目减少;而DSEN(0.4、0.5)组未见脱矿及微孔,表面为均质样再矿化层覆盖.结论菌斑液不同矿物质饱和度对釉质表面结构变化有重要影响,并进而影响表面下脱矿进程.     

不同浓度锶的含氟矿化液对脱矿牙釉质的再矿化作用研究

目的通过研究含不同浓度微量元素锶(Sr)的含氟矿化液对脱矿牙釉质表面显微硬度值的改变,探讨微量元素Sr的含氟矿化液对脱矿牙釉质的再矿化作用。方法采集和制备的牙釉质标本随机分为7组,采用酸蚀凝胶法制成人工龋,制备后的人工龋用不同浓度Sr(其中Sr的含量分别为0,10,50,100,150,200 mg/L)的氟矿化液(含氟均为100 mg/L)处理,采用表面显微硬度仪分别测定处理前后釉质表面显微硬度值。结果经不同浓度Sr的含氟矿化液作用后的离体牙标本表面显微硬度均比再矿化前有所增加。Sr浓度低于100 mg/L时,脱矿牙釉质表面显微硬度值随着Sr浓度增加而增加;但当Sr浓度高于100mg/L后,反而有所下降。结论含Sr的氟矿化液加强了牙釉质的再矿化并抑制脱矿,且其再矿化的程度与Sr浓度有相关性。     

牙釉质表面再矿化方法的研究进展

牙釉质表面脱矿是龋病及其他非龋性牙体病变(酸蚀症等)的主要病理改变之一,对脱矿牙釉质进行再矿化以恢复其应有理化特性的研究逐渐成为研究热点,本文对近年牙釉质表面再矿化方法 的发展作一综述.     

氟、镧对牙釉质脱矿和再矿化的影响

目的：对氟和镧对牙釉质的脱矿和再矿化进行文献综述，探讨氟和镧对于牙釉质脱矿和再矿化的机理。方法：电子期利文献查阅检索。结果：氟离子在牙釉质形成以及破坏后牙釉质重组中起重要作用；镧可以与牙釉质中的钙发生置换反应生成更耐酸的牙釉质，使牙齿外环境中的钙饱和度上升而阻止牙齿脱矿，并可促进脱矿釉质再矿化，从而提高牙齿的防龋能力。结论：低浓度氟有利于使脱矿向再矿化方向转化，从而使龋齿得以修复。在适宜的PH条件下，用含镧的制剂处理牙表面，改变了牙釉质的结构，提高牙釉质的抗酸能力。     

脉冲Nd∶YAG激光加氟化钠液对牙釉质、牙本质抗酸性能的影响

目的探讨脉冲Nd∶YAG激光+氟化钠液对牙釉质、牙本质抗酸性能的影响.方法将40个人牙的牙釉质、牙本质标本分成:激光+氟化钠组、激光组、氟化钠组、空白组(不处理)进行处理.再将所有标本用0.1 mol/L乳酸人工脱矿液(pH 4.5)37℃脱矿48 h,原子吸收分光光度计测脱矿液内Ca2+溶出量.结果在牙釉质和牙本质标本中,激光+氟化钠组Ca2+溶出量(×10-6 g)均值最低(62.055±5.879,137.474±4.444),其次是氟化钠组(84.053±10.422,153.816±4.097)、激光组(87.824±13.948,158.215±3.583),空白组Ca2+溶出量均值最高(143.760±5.443,182.726±16.115);激光+氟化钠组、氟化钠组、激光组与空白组间差异有高度显著性(P<0.01);激光+氟化钠组与氟化钠组间差异具有显著性(P<0.05)、与激光组间差异具有非常显著性(P<0.01).结论脉冲Nd∶YAG激光加氟化钠联合作用能有效地阻止离体人牙牙釉质、牙本质在酸性脱矿液中脱钙,因而具有抗龋性能.     

不同种类饮料致离体乳牙釉质脱矿的实验研究

目的 观察不同种类饮料对离体乳牙牙釉质的显微结构变化,比较不同饮料对乳牙釉质的脱矿作用.方法 将离体乳牙分别浸泡在碳酸类、果汁类、含乳类、茶类饮料中,每5 h换液1次,持续浸泡25 h.应用扫描电镜（SEM）观察4种不同种类饮料浸泡乳牙后的牙釉质显微结构的改变,用化学分析法测定4种饮料处理乳牙后,饮料中钙、磷含量的变化.结果 4种饮料浸泡乳牙后,SEM下可见乳牙牙面呈现不同程度的破坏,出现釉柱溶解、孔隙、凹坑等脱矿现象.4种饮料均能导致乳牙釉质中钙、磷的溶出,对于钙的总溶出量,雪碧组与鲜橙多组的差异无统计学意义（P＞0.05）,但均高于其他两组,差异有统计学意义（P＜0.05）;而对于磷的总溶出量,4种饮料间的差异均有统计学意义（P＜0.05）.结论 软饮料对乳牙釉质具有脱矿作用,脱矿作用的强弱与饮料的种类有关,应当控制儿童软饮料的消耗并要关注儿童口腔健康状况.     

菌斑细胞外液对牙釉质脱矿的影响

The aim of this study was to explore any substance in dental plaque which might affect the demineralization of enamel. Plaque fluid was prepared by centrifugation of pooled plaque from 56 young adults without periodontal diseases. Enamel was separated from healthy teeth of adolescents and crushed into powder. The enamel powder was treated separately by plaque fluid and synthetic plaque fluid (as a control, with similar calcium, fluoride content and pH as the natural). After this, the enamel powder was washed with PBS. Both the plaque fluid-treated and synthetic plaque fluid-treated enamel powder were demineralized by mixed organic acid (pH 4.5). The calcium content in both plaque fluids, PBS and organic acid after treatment with enamel powder was analysed by atomic absorption spectrophotometer. The results showed that there was no promoting effect in plaque fluid on demineralization of enamel, but, on the other hand, some protecting action was observed which might contribute to the presence of proteins in plaque fluid.     

Influence of apple juice on human enamel surfaces of the first and second dentition - an in vitro study

Dental erosion caused by acidic beverages is common and occurs with increasing tendency. The aim of this in vitro study was to analyse the erosive potential of apple juice on human enamel samples from the first and second dentition. Apple-juice-containing beverages (n = 23) were selected, and pH and buffering capacity were determined. Enamel samples were prepared from impacted, surgically removed wisdom teeth (20 mm superset2) and from deciduous teeth (16 mm superset2). Prepared enamel slices were incubated with a selected apple juice (pH = 3.5) for up to 24 h; the amounts of released calcium were determined colorimetrically, and mean surface roughness (Ra) of the enamel was measured using an optical profilometric device (perthometer, Mahr, G?ttingen, Germany). Controls were incubated with a 0.9 % sodium chloride solution under the same conditions (37 degrees C, humidified atmosphere of 5% CO subset2 and 95 % air). The surfaces of the enamel samples were visually examined by CLSM (Leica TCS SP2). The pH-values of the apple juices ranged from 3.3 to 4.2. Incubating the enamel slices (from both dentitions) with a selected apple juice caused a time dependent release of calcium. After 24 h, the primary dentition showed Ca-release values of 0.61 +/- 0.035 mg/ 20 mm superset2 and the second dentition of 0.41 +/- 0.085 mg/ 20 mm superset2; the surface roughness for the primary teeth was 6.8 +/- 1.09 microm and for the second dentition 6.2 +/- 0.41 microm. CLSM show structural changes on all surfaces when compared to the controls. In this in vitro study, the erosive potential of apple juice on teeth of the first and second dentition could be demonstrated. However, it must be considered that numerous modifying factors influence the human enamel surface in vivo; therefore, a direct translation from in-vitro conditions can only be done with caution.     

Effect of an oily calcium hydroxide suspension (Osteoinductal) on human periodontal fibroblasts. An in vitro study

The efficacy of an oily calcium hydroxide suspension (Osteoinductal) as an adjunct to periodontal regenerative therapy has been demonstrated in recent clinical and histological studies. However, little is known about the molecular mechanisms in vitro, particularly, about the effect of oily calcium hydroxide paste on periodontal ligament (PDL) cells. Therefore the aim of the present study was to analyze the mitogenic response of cultured PDL cells to Osteoinductal in comparison to calcium hydroxide and enamel matrix derivative (EMD) in vitro. Human periodontal ligament cells were derived from a third molar extracted for orthodontic reasons and incubated in the presence of Osteoinductal, calcium hydroxide, EMD, phosphate-buffered saline plus 10% glycerol (PBS) or standard culture medium for 15 and 60 minutes. The mitogenic response of the PDL cells was determined by Western Blot with antibodies specific for extracellular signal-related kinase (ERK)1/2 as well as the activated, tyrosine-phosphorylated form of ERK1/2 (p-ERK). Relative phosphorylation of ERK1/2 was normalized to total ERK1/2 levels by densitometry. Cell proliferation was measured after 1, 3 and 8 days using a Neubauer haemocytometer to determine the total cell number. Results demonstrated that the mitogenic response to Osteoinductal, calcium hydroxide and enamel matrix derivative was associated with the activation of ERK1/2 and was more pronounced as compared to PBS and standard culture medium treated cells. Although Osteoinductal and calcium hydroxide activated mitosis and caused phosphorylation of ERK1/2 in PDL cells, its effects were less pronounced as compared to EMD. Furthermore EMD exhibited the highest proliferative response in comparison to Osteoinductal, calcium hydroxide and the negative control after one, three and eight days. In conclusion, our data indicate that Osteoinductal enhances the mitogenic response of human PDL cells by activation of ERK1/2 and increases cell proliferation, however, it is inferior in comparison to EMD.     

可乐饮料对口腔牙釉质的早期损害研究

目的探究可乐饮料对口腔牙釉质的早期损害。方法收集40 颗下颌第三磨牙制备120 个牙釉质样本块,将120 个样本采用随机数表法分为4 组,每组30 个釉质块,其中一组为对照组。检测百事可乐、非常可乐、可口可乐3 种饮料中的磷钙含量,分别采用微量化学分析法和维氏显微硬度仪检测经3 种可乐饮料处理1、12 和24 h 后釉质块中磷钙含量的变化情况和釉质块表面显微硬度变化情况。结果百事可乐、非常可乐和可口可乐的磷浓度分别为（3.46±0.32）、（3.87±0.26）和（3.46±0.29）mmol/L,钙浓度分别为（3.58±0.25）、（0.09±0.06）和（1.32±0.19）mmol/L,3 种可乐饮料均会导致牙釉质中钙磷溶出。磷溶出浓度由大至小分别为百事可乐、非常可乐和可口可乐,钙溶出浓度由大至小分别为非常可乐、可口可乐和百事可乐,且随着时间的延长,磷钙溶出浓度逐渐降低,差异有统计学意义（P <0.05）。3 种可乐饮料导致牙釉质表面显微硬度值降低的程度由大至小分别为非常可乐、可口可乐和百事可乐,且随着时间的延长,牙釉质表面显微硬度值逐渐降低,差异有统计学意义（P <0.05）。结论可乐饮料均会导致牙釉质显微硬度降低,导致牙釉质酸蚀,导致牙釉质表面脱矿程度最严重的为非常可乐。     

乳牙釉质化学元素的微量分析

目的分析乳牙釉质化学元素的分布规律,为临床防龋提供依据。方法收集22例儿童26颗健康无龋乳牙进行牙釉质化学元素分析。结果不同性别及年龄段儿童乳牙釉质化学元素含量之间差异无统计学意义（P〉0．05）。钙、磷、镁、氯、氟、锶、锌的含量随深度增加而减少,各深度含量差异有统计学意义（P〈0．05）,均与深度呈负相关（P〈0．05）,钠、铝、钛的含量在乳牙釉质中分布均匀,各深度含量差异无统计学意义（P〉0．05）。结论乳牙釉质各元素与年龄、性别无相关性。其中钙、磷、镁、氯、氟、锶、锌、铝、钛与乳牙釉质矿化程度和抗龋性有关。     

Influences of bracket bonding on mutans streptococcus in plaque detected by real time fluorescence-quantitative polymerase chain reaction

Enameldemineralizationoccursfrequentlyduringorthodontictreatment.1,2Mutansstreptococcus(MS)isgenerallyconsideredtobeoneofthemajoretiologic agentsforenameldemineralization.3Previousstudieshave demonstratedthattheplacementofbracketsleadstoan increaseofMSinplaqueandsalivary.46Someotherstudies reportedthatwhitespotsoccurafewtimesmorefrequentlyon maxillarylateralincisorsthancentralincisors.1,2Asweknowthatsustainedreleaseoffluorideisoneofthe propertiesoffluorideadhesive,suchasglassionomer cement,w…     

CTLA-4Ig融合蛋白对ApoE基因缺陷小鼠动脉粥样 硬化的抑制作用

 【目的】 探讨CTLA-4Ig融合蛋白对高脂饮食饲养的载脂蛋白E基因缺陷小鼠(ApoE-/-)动脉粥样硬化病变的抑制作用&#65377;【方法】 25只10周龄ApoE-/-小鼠,高脂饮食饲养4周后,随机取5只验证AS病变(对照组);剩余20只随机分为4组(每组5只),继续高脂饮食饲养,分别采用CTLA-4Ig&#65380;PBS&#65380;IgG1腹腔注射,第4组不予处理;8周后取小鼠主动脉进行病理学检查,检测AS相关指标,包括斑块面积/管腔面积比&#65380;血管内膜/中膜厚度比,斑块内脂质&#65380;胶原和平滑肌细胞含量&#65377;【结果】 高脂饮食饲养4周后,出现明显AS病变&#65377;继续高脂饮食饲养8周,形成典型AS斑块,CTLA-4Ig组&#65380;PBS组&#65380;IgG1组和空白组的斑块面积/管腔面积比分别为0.27 ± 0.08&#65380;0.40 ± 0.08&#65380;0.43 ± 0.08和0.46 ± 0.10,较4周时(0.05 ± 0.01)明显增加(P < 0.05),4组的血管内膜/中膜厚度比分别为2.6 ± 0.6&#65380;6.0 ± 0.9&#65380;5.7 ± 0.8和5.9 ± 0.6,高于对照组(0.5 ± 0.1,P < 0.05),4组斑块内脂质含量(%)分别为26.0 ± 3.0&#65380;40.8 ± 5.7&#65380;40.6 ± 3.0和43.2 ± 5.7较4周时明显增加(7.2 ± 1.4,P < 0.05 )&#65377;采用CTLA-4Ig进行干预后,其斑块面积/管腔面积比&#65380;血管内膜/中膜厚度比和斑块内脂质含量显著低于PBS&#65380;IgG1和空白处理组(P < 0.05),而后3组间上述指标的差异无统计学意义(P > 0.05);CTLA-4Ig组斑块内胶原含量(16.0 ± 1.1)% 高于其他3组[(8.6 ± 1.2)%&#65380;(9.2 ± 1.5)%和(9.0 ± 1.3)%,P < 0.05)],其斑块内平滑肌细胞含量(11.8 ± 1.0)%明显高于其他3组[(7.8 ± 0.8)%&#65380;(7.5 ± 0.9)%和(7.3 ± 0.7)%,P < 0.05)],另外3组间上述指标的差异无统计学意义(P > 0.05)&#65377;【结论】 CTLA-4Ig融合蛋白能够阻抑高脂饮食饲养的ApoE-/- 小鼠动脉粥样硬化进程, 其增加斑块内血管平滑肌细胞生成胶原作用有助增加AS斑块的稳定性&#65377;     

Multibacterial artificial plaque. A model for studying carious process.

A multibacterial artificial plaque was established in vitro on enamel slabs incubated in mixed culture of Streptococcus sanguis, Streptococcus mutans (serotype c), Streptococcus salivarius, Lactobacillus casei and Actinomyces viscosus. Typical structure same as natural plaque was seen under microscope. The caries-like lesion produced under the plaque was observed in enamel sections. The lesion was similar in appearance to natural ones under optic and scanning electron microscopes. The acids produced in both culture media and artificial plaque were similar in composition and type to those produced in natural plaque after sugar attack. It is suggested that this kind of plaque model may be useful in studying carious process in vitro, because it is easily controlled either by changing the composition of bacteria or by adding different kinds of nutrient in the media. Moreover, the results will be easier to explain than those produced in natural ones.

     

不同浓度锌的含氟矿化液对人恒前磨牙釉质脱矿影响的体外研究

目的 研究含不同浓度微量元素锌(Zn)的含氟矿化液对离体恒前磨牙釉质脱矿的影响。 方法 采集和制备的牙釉质标本随机分为7组,将7组标本分别置于对照组(去离子水),不同浓度Zn(其中Zn的含量分别为0、10、50、100、150、200mg/L)的氟矿化液(含氟均为100mg/L)预处理8h,取出标本浸泡于酸蚀凝胶中,随后测定脱矿后8个时间点凝胶中的钙溶出量。 结果 含有不同浓度Zn的矿化液均有抑制牙釉质脱矿的能力(P=0.000),与对照组相比差异有统计学意义。同时含有Zn和F的比只含F的抑制脱矿能力增强,而且当Zn的含量为100mg/L时候,抑制脱矿的能力最强。 结论 Zn和F共同作用能显著提高抑制釉质脱矿作用,且其抑制釉质脱矿作用与Zn浓度有相关性。     

叶酸偶联壳聚糖载羟基喜树碱纳米药物制剂的体外释药性能

目的:探讨叶酸偶联壳聚糖载羟基喜树碱纳米药物制剂(FA-NPs)的体外释药性能。方法:按照浆-反向动态透析法进行体外模拟释放实验,建立高效液相色谱法测定药物释放量,观察FA-NPs的体外释药性能。分别考察不同释放介质(人工胃液,人工肠液和pH7.4的PBS)、搅拌速度(50、75和100r/min)和载药纳米粒的粒径(604、250和190nm)条件下FA-NPs的体外释药性能。结果:与pH7.4的PBS条件下的药物释放速率比较,FA-NPs在人工胃液中药物释放速率加快,在人工肠液中减慢,但在3种释放介质中均表现为先快速释放后缓慢释放的现象。在75和100r/min搅拌速度下FA-NPs具有相似的释药曲线,50r/min搅拌速度条件下FA-NPs的累积释放量较前两者降低。随着纳米粒粒径的增大,FA-NPs药物释放速率减慢。250nm粒径的FA-NPs在pH7.4的PBS中的累积释放时间超过40h,符合药物释放Higuchi方程:Q=0.0908t1/2+0.0324(R2=0.9844)。结论:FA-NPs体外表现出明显的先快速后缓慢释药现象,符合临床用药目的;药物的释放受释放介质、粒径大小和对释放介质的搅拌速度的影响。