含氟树脂氟释放率的体外试验

目的 通过观察几种不同浓度含氟树脂氟的释放率,试图寻找一种较为理想的给氟剂量,以达到预防义齿基牙龋的目的。方法 将含ＣａＦ２５％、１０％、１５％、２０％、２５％的树脂块分别放入１００ｍｌ、２００ｍｌ、５００ｍｌ蒸馏水中浸泡。用电位法测量水中氟离子浓度,观察树脂氟的释放速率及释放规律。结果 ２０％的含氟树脂其氟释放速率优于其它浓度的含氟树脂。结论 ＣａＦ２微溶于水,混入固化的树脂中,具有良好缓释氟的     

两种含氟流动树脂释氟能力的体外研究

目的：体外比较2种含氟流动树脂Beautifil Flow Plus F00和Dyad Flow的短期释氟量,以探讨2种材料释氟能力的差异。方法选取含氟流动树脂F00、DF和不含氟树脂Valux,制备直径10mm,厚1mm的样本,每组10个。将样本分别浸泡于5ml去离子水,第1、2、3、7、14、21、28d使用氟离子选择电极测量去离子水中的氟离子浓度,Va组为对照,比较F00和DF组前3d的单日氟释放及28d内各时间点的累积氟释放情况。结果 F00和Dyad Flow的释氟浓度均第1d最高;前3d单日释氟浓度呈下降趋势,差异有统计学意义(P<0．01);28d内2实验组均有缓慢持续的氟释放,随着时间延长累积释氟量增加;各个时间点,Dyad Flow组累积释氟量高于F00组,差异有统计学意义(P<0．01)。结论2种含氟流动树脂F00和Dyad Flow第1d氟释放最多,在测试时间内均有低量但持续的释氟能力,Dyad Flow释氟量略高于F00。     

氟化聚甲基丙烯酸甲酯体外释氟率的测定

目的:通过对含氟聚甲基丙烯酸甲酯体外释氟率的测定,为寻找较为理想的氟含量预防义齿基牙龋提供理论依据。方法:将分别含氟化钙、单氟磷酸钠10%、15%、20%、25%(重量比)5种不同浓度的热凝和自凝树脂各3块,分别于100ml、200ml去离子水中浸泡,定期取液,测量溶液中的氟离子浓度。结果:各浓度的含氟树脂块均能释放氟离子。结论:含单氟磷酸钠15%热凝树脂和10%的自凝树脂是比较好的含氟比例。含氟化钙20%热凝树脂和15%的自凝树脂是比较好的含氟比例。     

单氟磷酸钠加入可摘局部义齿热凝基托树脂后氟离子的体外释放实验

目的:通过观测加单氟磷酸钠热凝基托树脂的氟释放率,寻找一种较为理想的给氟剂量预防义齿基牙龋.方法:将含单氟磷酸钠0、10%、15%、20%、25%(单氟磷酸钠占牙托粉的重量比)5 种不同浓度的热凝树脂各3 块,每块重1 g,分别随机放入装有100、200、500 ml蒸馏水的聚乙烯盒中浸泡,前2 种溶液定期完全更换浸泡用的蒸馏水(第1、2、3、6、9、16天换水,以后为每7 d换水,共2 个月),每次留取2 ml浸泡液待测.500 ml溶液定期取浸泡液2 ml,取液期间不换水,第3、6、9 天取液1 次,以后每7 d取液1 次,待测,共2 个月.用氟离子选择电极法测量待测溶液中氟离子浓度,观察和对比树脂中氟的释放速率及释放规律.结果:各浓度含氟树脂块在观察期间于浸泡液中均能释放不同浓度氟离子.结论:将单氟磷酸钠加入热凝基托树脂中,具有良好的缓释氟的作用;15%的单氟磷酸钠是较好的加氟比例.     

含氟充填材料释氟吸氟和再释氟的研究

目的 为了研究含氟充填材料能否长期稳定释放氟而发挥抗龋效能,本文观察了玻璃离子水门汀和含氟复合树脂在用含氟牙膏处理前后两个时期的释氟情况。方法 第一阶段,将玻璃离子水门汀和含氟复合树脂各６个标本,分别浸泡于去离子水中,测定其在不同时间氟的放量;第二阶段。用含氟牙膏处理各标本后,再测定其在不同时间氟的释放量。结果 当这两允填材料释氟水平降低后,用含氟牙膏处理,琪 释放量明显回升     

含氟牙釉质粘接剂释氟的实验研究

目的：研究国产含氟牙釉质粘接剂的释氟性能。方法：制备含氟牙釉质粘接剂I型和Ⅱ型的测试标本，以ORION720型离子选择性氟电极、参比电极测试氟离子浓度。结果：I型及Ⅱ型含氟牙釉质粘接剂均有氟离子释放，且在第一个24h后氟离子浓度下降显著，可维持21d左右；Ⅱ型含氟牙釉质粘接剂初始状态释放氟离子水平较高。结论：I型及Ⅱ型含氟牙釉质粘接剂均有释氟性能,而以Ⅱ型含氟牙质粘接剂较佳。     

2种含氟窝沟封闭剂氟释放的体外研究

目的:观察和比较2种含氟窝沟封闭剂在人工唾液中的释氟情况.方法:将2种含氟窝沟封闭剂各制备5个6 mm×1.5 mm的盘状标本,浸入12 mL人工唾液中,恒温37℃.采用氟离子选择性电极法,分别于第1、2、3、7、14、21、28、35天测定2种窝沟封闭剂氟离子的释放量.结果:2种含氟窝沟封闭剂均在第1天的氟释放量最高,然后1周内急剧降低,在14～35 d内维持于稳定水平.在各时间点,玻璃离子封闭剂氟释放量均高于含氟树脂封闭剂,差异有统计学意义(P＜0.01).结论:新型含氟树脂窝沟封闭剂与玻璃离子封闭剂均能够作为氟库在一定时间内持续缓慢地向周围液体环境释放氟离子,对于窝沟封闭剂的防龋性能可能具有潜在的增强作用.     

含氟热凝树脂预防可摘局部义齿基牙龋的体外研究

目的:研究基托局部含氟对基牙的防龋作用.方法:将10颗健康离体牙制成20块2～3mm厚的釉质块,采用配对设计的实验方法,利用简易人工口腔装置,分别随机地紧邻于含氟及无氟热凝树脂块,流动人工唾液冲洗.每周测定人工唾液的氟浓度,四周后测定各釉质块的表面显微硬度及抗酸性.结果:两组中人工唾液氟浓度无显著性差异,表面显微硬度及酸蚀后的龋损深度有显著性差异.结论:含氟树脂有利于预防可摘局部义齿基牙龋.     

含氟牙膏中氟离子测定方法的研究

近年来,随着我国口腔保健新产品的不断开发,含氟牙膏日渐增多。离子态的氟是含氟牙膏中的有效防龋成分,因此准确、迅速地测定牙膏中的氟离子含量,对评价含氟牙膏的效果是非常必要的。现行的中华人民共和国国家标准（ＧＢ８３７２—８７）在关于牙膏测定中规定用硝酸钍...     

含氟牙膏用量对学龄前儿童氟摄入影响的研究

目的 观察含氟牙膏（1000μg/g)不同使用量对学龄前儿童氟化物摄入量的影响。探索学龄前儿童使用含氟牙膏较为合理，安全的用量。方法 采用离子选择性氟电极，测定3个年龄组使用的不同用量含氟牙膏后24h尿氟排泄量，并以使用含氟牙膏前尿氟排泄量作为自身对照。结果 含氟牙膏用量及年龄对学龄前儿童24h尿氟排泄均有显著影响，经SPSS统计轮换民统计有显著差异。结论 学龄前儿童刷牙时因误咽部分含氟牙膏引起氟化物摄入增加，6岁以下的儿童，要减少含氟牙膏的使用量，每次用量不宜超过豌豆大小（约0.25g)。     

Inhibition of demineralization in vitro around fluoride releasing materials

Replacement of restorations because of secondary caries is a continuing problem in restorative dentistry. This investigation assessed the capacity of fluoride-releasing restorative materials to resist caries in vitro when used in roots. Class 5 cavities were prepared in buccal and lingual surfaces of 30 extracted premolars and restored with one of three polyacid modified resin composites (F-2000, Hytac and Compoglass F), a resin modified glass-ionomer cement (Fuji II LC) a conventional glass ionomer (Ketac-Fil), and a resin composite (Z-100). After 5 weeks in an acid gel for caries-like lesion formation, the teeth were sectioned longitudinally and examined with polarized light. The results showed that restoration of caries with polyacid modified resin composites and resin modified glass ionomer cements may be of great importance in the prevention of secondary caries around the restorations in roots. Clinical Relevance Light cured fluoride-releasing restorations may inhibit caries-like lesions. Inhibition of demineralization in vitro around fluoride releasing materials.     

氟保护漆的释放研究

目的：观察氟保护漆在去离子水中的释放情况，方法：采用氟离子选择电极法，结果：在整个10d的实验期间，氟保护漆都释放一定量的氟，且随浸泡时间延长而稀释出量逐渐下降。结论：氟保护漆释氟主要发生在第1h，同时在一定时期内能缓慢持续释放到周围环境中，具有一定的防龋潜力。     

Abrasive wear of filled and unfilled resins in vitro

abstract — The present investigation was initiated to evaluate the wear resistance of filled and unfilled resins which may be suitable for fissure sealing. Two commercial unfilled resins (Adaptic Glaze(r) and Delton®), three degrees of diluted composite (Adaptic® diluted with Adaptic Bonding Agent®) and undiluted composite (Adaptic) were studied. Abrasion was caused by 400-grit silicon carbide paper in a mechanical surface grinder. Ten specimens of each of the material samples were tested. The unfilled resins were abraded three to six times more readily than the composite samples. Undiluted composite was the most resistant, whereas samples of increasing degrees of dilution were abraded to increasing extents. However, even the most diluted composite, although very fluid, was at least three times more resistant than the unfilled samples. The results of this study indicate that adding inorganic filler particles to a resin, even in small amounts, greatly enhances the wear resistance of such materials.     

玻璃离子水门汀氟释放的离体研究

目的：观察两种临床常用的传统化学固化型玻璃离子水门汀Ｓｈｏｆｕ和ＣｈｅｍｆｉｌＳｕｐｅｒｉｏｒ在去离子水中氟释放情况。方法：采用氟离子选择电极法。结果：在整个３３ｄ的实验期间，两种材料都释放一定量氟，且随浸泡时间延长而氟释放量逐渐下降。两种材料浸泡第１天氟释放量最大，前３ｄ氟释放累计总量大于以后每１０ｄ氟释放量。结论：提示玻璃离子水门汀中氟释放存在初始爆发效应，同时在一定时期内能缓慢持续释放到周围环境中，具有一定的防龋潜力。     

Dimensional stability and dehydration of a thermoplastic polycarbonate-based and two PMMA-based denture resins

This study compared the dimensional stability and dehydration of a thermoplastic polycarbonate denture base resin with two conventional polymethyl methacrylate denture base resins. Maxillary complete dentures were fabricated from the three denture materials and the accuracy of fit along the posterior palatal border of the cast used in processing was measured. Measurements were conducted at five palatal locations immediately after processing and at 7 and 30 days during immersion in water (23 degrees C) and at 7 and 30 days during dehydration (23 degrees C, 65-75% relative humidity). Percentage mass loss during dehydration was determined with an electronic balance. The thermoplastic material was separately compared with each of the conventional resins using a modified Welch two-sample t-test, with a Bonferroni correction for P values. For mean palatal dimensional change, the thermoplastic resin was generally not statistically different from the conventional resins after processing and during immersion (P > or = 0.06), but was generally less than the conventional resins during dehydration (P < or = 0.02). For mean percentage mass loss, the thermoplastic resin consistently showed much smaller, statistically significant values compared with the conventional resins (P < 0.001). It was concluded that the thermoplastic resin should show dimensional changes in service comparable with the conventional resins, but less dimensional change caused by dehydration.     

三种义齿基托材料抗白色念珠菌黏附性能的比较

目的比较3种义齿基托材料的抗白色念珠菌黏附性能。方法将热凝基托树脂、不碎胶树脂、弹性材料树脂义齿基托材料制备成粗糙度相同的标准试样,每组10个。用白色念珠菌(ATCC 90028)菌液对各试样黏附培养24h、48h、168h后,分析白色念珠菌对试件表面的黏附。结果在培养24h时,3组试件白色念珠菌黏附量差异无统计学意义(P0.05);培养48h时,除不碎胶树脂组和弹性材料树脂组外,其余两两之间差异均有统计学意义(P0.05);培养168h时,3组试件两两之间差异均有统计学意义(P0.05),白色念珠菌黏附量计数,热凝基托树脂不碎胶树脂弹性材料树脂。结论与传统热凝树脂基托相比较,不碎胶树脂基托和弹性材料树脂基托能减少白色念珠菌的黏附。     

An in vitro quantitative antibacterial analysis of amalgam and composite resins

OBJECTIVES: Antibacterial properties of restorative dental materials such as amalgam and composite resins may improve the restorative treatment outcome. This study evaluates the antibacterial properties of three composite resins: Z250, Tetric Ceram, P60 and a dental amalgam in vitro. METHODS: Streptococcus mutans and Actinomyces viscosus served as test microorganisms. Three quantitative microtiter spectrophotometric assays were used to evaluate the effect of the restorative materials on: (i) early-stage biofilm using a direct contact test (DCT); (ii) planktonic bacterial growth; (iii) bacterial growth in the materials' elute. For comparison purposes, agar diffusion test (ADT) was also performed. RESULTS: The effect of the composite resins on bacterial growth was minimal and limited to a few days only. One-week-aged composites promoted growth of S. mutans and A. viscosus. The antibacterial properties in direct contact were more potent than in planktonic bacterial growth. Amalgam showed complete inhibition of both bacteria in all phases, and the effect lasted for at least 1 week. The materials' elute had no effect on both bacterial growth with the exception of complete inhibition of S. mutans in amalgam. The later results correlated with the ADT. CONCLUSIONS: The present findings demonstrate potent and lasting antibacterial properties of amalgam, which are lacking in composite resins. This may explain the clinical observation of biofilm accumulated more on composites compared to amalgams. It follows that the assessment of antibacterial properties of poorly-soluble materials has to employ more than one assay.     

五种充填用流动性复合树脂的耐磨性能研究

目的比较5种充填用流动性复合树脂的耐磨性能,为临床选择适用于[牙合]力承担区直接充填治疗的流动性复合树脂提供参考。方法以可压实复合树脂(Majesty)为对照组,选用5种充填用流动性复合树脂(A组:Filtex 350 XT Flow;B组:Beautifil Flowable Plus;C组:Clearfil Majesty LV2;D组:Unifil LoFlo Plus;E组:Sonic Fill组)为研究对象,每组材料制备6个半球形试件。在微摩擦磨损实验机下,树脂试件垂直加载20 N,与牛牙釉质往复对磨1万次后测量球头磨斑直径并在扫描电镜下观察磨斑微观形貌。采用单因素方差分析比较各组磨斑直径差异。结果对照组、A、B组磨斑直径[分别为(1033±43)、(1068±48)、(1237±86)μm]差异无统计学意义(P>0.05),C、D、E组磨斑直径[分别为(1550±150)、(1384±222)、(1525±81)μm]均显著大于对照组和A组(P<0.05)。扫描电镜显示,对照组、A、B组填料粒度范围较大,磨耗面可见填料的碎裂和局部缺损;C、D、E组填料颗粒较小,并可见多处整块填料脱落的痕迹。结论填料粒度范围大的流动性复合树脂的耐磨性能与可压实复合树脂相当,有望用于[牙合]力承担区直接充填治疗。     

Clinical evaluation of four composite resins in posterior teeth. Five-year results

Four different composite resins (three small particle and one microfill) were placed in 106 posterior teeth and followed over a five-year period. Colour and marginal discoloration characteristics were assessed from standard photographs, and wear evaluated by standardized measurement of cavity wall exposure and scanning electron microscopy of replicas. The colour of the materials changed, but not to an unacceptable degree, over the five-year period, and marginal discoloration increased slightly. The wear rate of the four materials was similar, and appeared to decrease after about 2-4 years. Some materials exhibited surface damage, and some of the microfill restorations failed catastrophically.