漂白剂,遮色剂对树脂—釉质粘结强度影响的实验研究

本文模拟临床操作过程，分别对离体牙进行漂白或遮色，再行树脂粘结，与未进行漂白或遮色的对照本一并进行剪切力测试，以探讨漂白剂，遮色剂对树脂－釉质粘强度的影响，实验表明（Ｉ）漂白剂进行５的使用将导致树脂，釉质粘结强度下降，但与漂白剂的类型，漂白时间、漂白剂中过氧化氢浓度有关，（２）使用Ｂａｙｅｒ和３Ｍ遮色剂涂层对树脂－釉质粘结束强度无影响，根据实验，临床上使用４０％过氧化脲，漂白时间控制在１０分钟以内     

Panavia F遮色树脂黏结剂对Cerinate瓷贴面修复不同染色程度模拟四环素牙遮色效果研究

背景：关于四环素牙的美学修复大多局限于临床上的观察,而基础的实验研究相对较少。 目的：观察Cerinate瓷贴面修复轻度(黄色)、中度(黑灰色)、重度(黄-灰色)、极重度(灰褐色)4种不同染色程度模拟四环素牙的颜色变化。 方法：将模拟四环素牙试件按轻、中、重、极重度4种不同染色程度分为4组,每组10个试件,用Cerinate瓷贴面进行修复,Panavia F遮色树脂黏结剂黏结,用电子测色仪测定修复体黏结前及黏结后的L*、a*、b*值及变化。 结果与结论：瓷贴面黏结前与黏结后的表面的L*、a*、b*值之间差异有显著性意义(P < 0.05)。轻度四环素牙选用未含有遮色剂的树脂黏结剂黏结会较小,中、重度四环素牙在用含有遮色剂的遮色树脂黏结剂黏结后对修复体的颜色遮色效果较好,而对极重度四环素牙遮色效果不好,最好选用其他修复体修复。     

不同瓷表面处理剂对树脂-遮色瓷结合强度的影响

为比较不同表面处理剂对树脂-遮色瓷结合强度的影响,制作表面烤制有遮色瓷的金属基底5组,瓷表面酸蚀后,其中4组分别涂布RelyX Ceramic Primer(RCP)、Porcelain Bond Activator(与SE Bond Primer 1∶1混合使用)(PBA)、Shofu Porcelain Primer(SPP)、SE Bond Primer(SEP)四种表面处理剂,剩余一组作为空白对照。将5组试件与树脂粘接后测剪切强度,并分析、观察断裂模式。结果显示,所有实验组粘接强度均高于对照组;PBA组的粘接强度最高[(37.52±2.14)MPa],组内试件多为混合破坏(金瓷断裂和遮色瓷内聚断裂);SPP、RCP组高于SEP组(P0.05),组内试件多为混合破坏(粘接界面断裂和遮色瓷或树脂内聚断裂);SEP组和对照组内试件多为粘接破坏。因此,表面处理剂可提高遮色瓷与牙科复合树脂的粘接强度,二者粘接强度满足临床要求。     

丙烯酸树脂表面的不同方法对硅橡胶软衬的粘结效果的影响

目的 研究丙烯酸树脂表面的不同处理方法与硅橡胶软衬抗剪切强度及三点弯曲强度的影响。方法 制作50 mm×10 mm×3 mm的树脂片60片,并随机分为三组每组20片。将各组树脂片的粘结面（10 mm×10 mm）分别进行如下处理,A组为无特殊处理组,B组为单体处理组,C组为低温等离子体处理组。每组的两个树脂片粘结面间衬以2 mm的软衬材料,制成抗剪切强度试件,进行抗剪切强度测试。另制作64 mm×10 mm×3.3 mm树脂片30个,随机分为三组每组10个,处理方法同上,测试三点弯曲强度。结果 低温等离子体处理丙烯酸树脂与硅橡胶软衬的粘结强度高于单体处理组,差异有统计学意义（P<0.05）,对树脂的挠曲强度无影响,与对照组相比,差异无统计学意义（P＞0.05）,单体处理组三点弯曲强度,优于对照组,差异有统计学意义（P＜0.05)。结论 低温等离子体处理丙烯酸树脂比单体处理粘结强度提升的更高且不影响树脂的机械性能,为硅橡胶软衬的临床应用提供了更好的理论指导。     

填料和粘结辅助剂在EB复合树脂与Ni-Cr合金粘结中的作用

本文测试了七种不同填料的EB复合树脂Ni-Cr合金的抗张粘结强度,并以扫描电镜观察填料的超微表面形态;对使用七种粘结辅助剂后,Ni-Cr合金与EB复合树脂的抗张粘结强度进行了比较。实验发现:同一树脂不同的填料,其抗张粘结强度不同;KH-570和含4META的单一树脂可明显提高金属-树脂粘结强度;在金属和树脂粘结中,选用锶玻璃填料并应用KH-570后,抗张粘结强度可以达到280kg/cm~2。     

用多步和一步结合剂后钛增强的核心材料的剪切结合强度

该体外研究的目的是比较用５种多步（ｍｕｌｔｉｓｔｅｐ）结合剂（ｂｏｎｄｉｎｇａｇｅｎｔｓ）粘结的钛增强的核心材料Ｔｉ－Ｃｏｒｅ的剪切结合强度和５种配对的一步（ｓｉｎｇｌｅ－ｓｔｅｐ）结合剂粘结结合强度。试样分１０组，每组１０个，共使用１００个最近拔出...     

超声洁治术对金属烤瓷冠边缘微渗漏的影响

目的探讨超声洁治术对金属烤瓷冠边缘微渗漏的影响。方法选取离体磨牙70颗,随机分成7组（A—G组）,每组10颗,按烤瓷冠要求常规牙体预备,制作钴铬合金烤瓷冠。A、B组应用聚羧酸锌水门汀粘结;C、D组应用玻璃离子水门汀粘结;E、F、G组应用树脂粘结剂粘结。各组经冷热循环实验后,B、D、F组按要求进行单次超声洁治术;G组进行3次超声洁治术;A、c、E组作为对照组,不进行超声洁治术。所有实验牙经1％亚甲蓝染色后剖开牙体和烤瓷冠,观测各组的微渗漏深度。结果超声洁治前采用不同粘结剂粘结的牙体微渗漏深度A组〉c组〉E组（均P〈O．05）。与未进行超声洁治术组比较,使用聚羧酸锌水门汀、玻璃离子水门汀粘结,进行单次超声洁治术的牙体微渗漏深度B组〉A组[（3．36＋1．11）mm比（2．55~0．71）mm,P〈0．05],D组〉c组[（2．96~0．93）mm比（2．02＋0．79）mm,P〈0．05]。而使用树脂粘结剂的牙体进行单次和3次超声洁治术后的牙体微渗漏深度与未进行超声洁治术的牙体比较,即E、F、G3组间差异并无统计学意义（尸〉0．05）。结论超声洁治术对玻璃离子水门汀和聚羧酸锌水门汀粘结的烤瓷冠边缘封闭性产生明显破坏,而对树脂粘结剂粘结的烤瓷冠边缘封闭性无明显影响。     

BODIPY光敏药物在牙齿美白上的应用研究

目的探讨氟化硼络合二吡咯甲川（BODIPY）光敏药物结合光动力治疗（PDT）在牙齿美白的应用及对牙齿表面釉质的影响。方法人离体牙分别经过氧化氢和BODIPY光敏药物光动力美白处理后,使用vita比色板和扫描电镜观察,分析不同方法对牙齿的美白效果及美白前后牙齿表层釉质在晶体和丑微结构上发生的改变。结果经过美自处理前后进行对比,过氧化氢法美白效果显著,但牙齿表面釉质出现严重脱矿现象;BODIPY光敏药物PDT法的美白效果良好,牙齿光滑,牙齿表面有再矿化现象。结论利用BODIPY光敏药物的PDT法对牙齿具有一定的美白效果,并能促进牙齿表面釉质的再矿化,有望成为牙齿美白的新方法。     

Dot-IGSS法检测SLE患者血清中抗肾小球基底膜及肾小管抗体的研究

方法：本实验采用斑点免疫金银染色（Ｄｏｔ－ＩＧＳＳ）法对５０例ＳＬＥ患者血清中的肾小球基底膜抗体（ＧＢＭ－Ａｂ）及肾小管抗体（Ｔｕｂ－Ａｂ）进行检测。结果：ＧＢＭ－Ａｂ阳性率达６２％，Ｔｕｂ－Ａｂ阳性率达７６％。与患者尿蛋白检查（阳性率为４８％）比较，上述自身抗体检出率较高。此外，ＧＢＭ－Ａｂ或Ｔｕｂ－Ａｂ检测阳性患者与肾活检诊为狼疮性肾炎（ＬＮ）相符率达１００％。结论：ＧＢＭ－Ａｂ或Ｔｕｂ－Ａｂ的检出可为临床早期诊断ＬＮ提供可靠的证据     

同型半胱氨酸对培养大鼠心肌细胞牛磺酸摄取及其影响机制的研究

目的：观察同型半胱氨酸（ＨＣＹ） 对培养大鼠心肌细胞牛磺酸摄取的影响及其影响机制。方法：应用［３ Ｈ］－ 牛磺酸同位素检测技术,测定ＨＣＹ 不同浓度或在ＨＣＹ 作用下牛磺酸作用不同时间对牛磺酸摄取量的影响,以及应用蛋白激酶Ｃ（ＰＫＣ） 抑制剂Ｈ７ 和多粘菌素（ｐｏｌｙｍｙｘｉｎ Ｂ, ＰＢ） 观察大鼠心肌细胞在ＨＣＹ 作用下对牛磺酸摄取量的影响。结果：ＨＣＹ 呈浓度依赖性刺激大鼠心肌细胞对牛磺酸的摄取,１０ ～１００ μｍｏｌ／Ｌ 浓度组分别较阴性对照组牛磺酸摄取量增加３３ ％ （ Ｐ＜ ０－０１） ～６７ ％ （ Ｐ＜ ０－０１） ;ＨＣＹ 刺激心肌细胞摄取牛磺酸量呈时间依赖性,牛磺酸作用时间２ 、５ 和１０ ｍｉｎ时分别较作用１ ｍｉｎ 时增加４８ ％ 、２４５ ％ （ Ｐ＜ ０－０１） 和３０６ ％ （ Ｐ＜ ０－０１） ;ＨＣＹ 刺激摄取牛磺酸量分别为Ｈ７ 和ＰＢ 作用减少３５ ％ （ Ｐ＜ ０－０１） 和４３ ％ （ Ｐ＜ ０－０１） 。结论：ＨＣＹ 促进大鼠心肌细胞摄取牛磺酸的作用可能与ＰＫＣ 所介导的蛋白磷酸化过程有关     

DNA-Damaging Effects of Dental Bleaching Agents

We studied DNA-damaging effects of dental bleaching systems containing hydrogen peroxide and/or carbamide peroxide by the “comet assay” (alkaline version). Dental bleaching systems in a hydrogen peroxide concentration range from 0.03 to 30 mM produced a genotoxic effect on isolated HeLa cells in vitro comparable with the effects of pharmacopoeial hydrogen peroxide or urea peroxide. Catalase protected the cells against products containing hydrogen peroxide and had no effect on the genotoxicity of samples containing carbamide peroxide.     

Effect of bleaching agents on the fluoride release and microhardness of dental materials

The use of bleaching agents has become a popular procedure for whitening teeth. Recently introduced polyacid-modified composite resins (compomers) have several favorable features, such as improved physical properties and fluoride release. Because these two materials have many possibilities to interact in the oral cavity during dental treatment, it is necessary to understand such interaction. To evaluate the effect of a bleaching agent on dental restoratives, three compomers were photopolymerized and then bleached for 1, 2, 3 and 5 days with the use of 30% hydrogen peroxide. Fluoride release, surface microhardness, and surface modifications were evaluated. It was found that the cumulative fluoride release was found to be linearly correlated to the tested periods of bleaching in all compomers. Among the tested compomers, F2000 showed the highest cumulative fluoride release. Bleached compomers became soft because of surface degradation, so the surface microhardness decreased. F2000 showed an apparent crack formation that was not observed in other compomers. The nearly linear correlation between the filler content and microhardness was found in the control samples. However, the same correlation was not observed after the compomers were stored in a bleaching agent or distilled water.     

The influence of hair bleach on the ultrastructure of human hair with special reference to hair damage

The influence of human hair bleaching agents with different bleaching strength on the ultrastructure of human hair was studied using a transmission electron microscope (TEM) and an energy dispersive X-ray spectrometer equipped with TEM (EDS-TEM). Two kinds of bleaching agents were used: a lightener agent with a weak bleaching effect and a powder-bleach with a stronger bleaching effect. From the comparison of the bleaching properties obtained by the electronic staining of black and white hair samples, it was suggested that the permeability of hair was increased by bleaching, and there was an increase of the stainability of hair subjected to electronic staining. The bleaching action provoked the decomposition of melanin granules and the flow out of granular contents into the intermacrofibrillar matrix. Some metal elements were detected in the melanin granular matrix by EDS-TEM. As a result, the diffusion of metal elements into the intermacrofibrillar matrix promoted further damage to the hair by catalytic action with the hydrogen peroxide in the bleaching agents outside the melanin granules. Further study will lead us to the edge of the development of a new bleaching agent, which reacts only with melanin granules and causes the minimum of damage to outside the melanin granules.     

Effect of elapsed time following bleaching on the shear bond strength of composite resin to enamel

The purpose of this study was to investigate the effect of post-treatment time on the shear bond strength of composite resin to enamel after bleaching with 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching systems. One hundred and thirty-five flattened labial enamel surfaces obtained from human mandibular incisors were divided into two bleaching groups of 10% CP (n = 60) and 35% HP (n = 60) and a control group (n = 15). Specimens in the control group (group 1) were not bleached. Each bleaching group was then divided into four subgroups (n = 15). For both CP and HP groups, group 2 consisted of specimens bonded immediately after bleaching. In groups 3, 4, and 5, specimens were immersed in artificial saliva for 24 h, 1 week, or 2 weeks after bleaching, respectively. After the specimens were bonded with Clearfil SE Bond and Clearfil ST, they were tested in shear until failure. For both CP and HP groups, shear bond strength of composite resin to enamel that was bonded immediately after bleaching was significantly lower than that of unbleached enamel (p < 0.05). However, in CP group restored after 24 h, the bond strength returned to values close to those of nonbleached enamel (p > 0.05). It took 1 week to return to conditions that lead to control bond values for HP bleaching applications (p > 0.05). The results of this study proved that immediate bonding of composite to enamel bleached with 10% CP and 35% HP gels result in a significant decrease in shear bond strength. It is advisable that composite resin application onto bleached enamel surfaces should be delayed at least 24 h for 10% CP and 1 week for 35% HP.     

Investigation of three home-applied bleaching agents on enamel structure and mechanical properties: an in situ study

The safety of at-home tooth bleaching, based upon carbamide peroxide (CP) or hydrogen peroxide (HP) as the active agent, has been questioned. The aim of the present study was to investigate the effects of three differently concentrated home-applied bleaching agents on human enamel under in situ conditions. Sixty specimens were divided randomly into four groups and treated with 10% CP, 15% CP, 20% CP, and distilled water, respectively. Raman spectroscopy, attenuated total reflectance-infrared (ATR-IR) spectroscopy, atomic force microscopy (AFM), microhardness, and fracture toughness (FT) measurements were conducted to determine variations on enamel structure and mechanical properties before and after the bleaching process. Raman revealed little variation of Raman relative intensity after treatment with CP, which was consistent with the results of ATR-IR, AFM, and microhardness analyses. In addition, laser-induced fluorescence (LIF) intensity, and FT showed significant decreases on CP-treated specimens. These findings suggested there were minimal demineralization effects of the three at-home bleaching agents on enamel in situ. However, the decrease of LIF intensity and FT on enamel seemed to be inevitable.     

硅烷偶联剂的浓度对钡玻璃与树脂基质间粘接强度的影响

选用７种不同浓度的γＭＰＳ乙醇溶液（０．０１％、０．０５％、０．１％、０．５％、１％、５％和１０％ｗｔ）分别对钡玻璃试块表面进行硅烷化处理,以观察其对钡玻璃与树脂基质间结合强度的影响。经抗张粘接强度测试和断裂界面分析,结果表明：随着γＭＰＳ溶液浓度的增大,钡玻璃与树脂间的结合强度呈现出由低到高,再由高到低的转变。γＭＰＳ溶液的浓度在０１％～０５％范围内可使钡玻璃与树脂间达到最佳的抗张粘接强度。随着该溶液浓度的变化,试件的粘接断裂破坏形式呈现出由粘接破坏→混合破坏→内聚破坏→混合破坏→粘接破坏的转换现象。     

Bleaching-induced colour change in plastic filling materials

The purpose of this in vitro study is to compare the colour changes of five different tooth-coloured restoratives: Ormocer (Definite/Degussa), compomer (Dyract AP/Dentsply De Tray), packable composite (Filtek P60/3M), flowable composite (Filtek Flow/3M) and hybrid composite (Filtek Z250/3M) after two different bleaching regimens [Vivastyle (10% carbamide peroxide)/Vivadent and Crest Professional Whitestrips (6.5% hydrogen peroxide strip bands)/Procter & Gamble]. Fifteen specimens of 30 x 30 x 2mm(3) size were fabricated from each material and randomly divided into three groups of five. Specimens in group one were stored in distilled water at 37 degrees C for two weeks and served as control. Group two specimens were treated with Vivastyle for two hours per day for two weeks and group three specimens were treated with Whitestrips for 30 min twice daily for two weeks. During the test period the specimens were kept at 37 C and in 100% relative humidity. At the end of the bleaching regimens colour measurements of the control and test groups were made with UV visible recording spectrophotometer. Colour changes were calculated with the use of the CIE-LAB uniform colour scale and compared by the use of Kruskall-Wallis test, followed by the Mann-Whitney U test. Control, Vivastyle and Whitestrips L*, a* and b* values differed significantly for all materials except Filtek Z250 (p < 0.05). All restorative materials demonstrated significantly higher colour change (DeltaE) with Whitestrips (p < 0.05). Dyract AP demonstrated the highest colour change both for the bleaching regimens followed by Filtek Flow, Definite, Filtek P60, and Filtek Z250 showed the smallest colour change. Colour change of plastic restorative materials during bleaching is both filling material and bleach specific.     

Heavily pigmented melanocytic neoplasms: comparison of two melanin-bleaching techniques and subsequent immunohistochemical staining

The effect of melanin bleaching using permanganate/oxalate and dilute hydrogen peroxide on subsequent immunohistochemical staining of heavily pigmented melanocytic neoplasms is investigated. Permanganate/oxalate precluded the use of some antibodies but allowed much faster bleaching times, whereas dilute hydrogen peroxide enabled a full range of antibodies to be used, yet bleaching times were far longer. Each technique has advantages; however, the choice of method should be determined by the nature of the information needed to make a diagnosis and the speed at which a report is required.     

The effect of 30% hydrogen peroxide on the color of compomers

The interaction between bleaching agents and recently introduced compomers has several issues that need to be explored, including morphology and mechanical properties. To investigate the effect of 30% hydrogen peroxide, a bleaching agent, on the color of compomers, three compomers (Compoglass F, Elan, and F2000) were polymerized, bleached up to 120 h, and then measured to determine the reflectance of the specimen during the bleaching process. Color differences were evaluated from the reflectance and color values that were represented by CIE L*a*b* values. Compomers stored in distilled water were used as a source of reference. Teeth were also used for comparison. Color differences for both the tested teeth and compomers and different periods of bleaching and soaking in distilled water showed statistically significant difference (p < 0.0001). Among the tested compomers, Compoglass F demonstrated the highest color difference. In addition, the color differences were maximal during the first 24 h. After 24 h, the color difference increased nearly linearly. Compomers stored in both a bleaching agent and distilled water did not exhibit much color difference between them. However, the color difference between teeth and compomers was considerable.     

Probing skin interaction with hydrogen peroxide using diffuse reflectance spectroscopy

Hydrogen peroxide is an important oxidizing agent in biological systems. In dermatology, it is frequently used as topical antiseptic, it has a haemostatic function, it can cause skin blanching, and it can facilitate skin tanning. In this work, we investigated skin interaction with hydrogen peroxide, non-invasively, using diffuse reflectance spectroscopy. We observed transient changes in the oxyhaemoglobin and deoxyhaemoglobin concentrations as a result of topical application of dilute H(2)O(2) solutions to the skin, with changes in deoxyhaemoglobin concentration being more pronounced. Furthermore, we did not observe any appreciable changes in melanin absorption properties as well as in the skin scattering properties. We also found no evidence for production of oxidized haemoglobin forms. Our observations are consistent with an at least partial decomposition of hydrogen peroxide within the stratum corneum and epidermis, with the resulting oxygen and/or remaining hydrogen peroxide inducing vasoconstriction to dermal blood vessels and increasing haemoglobin oxygen saturation. An assessment of the effects of topical application of hydrogen peroxide to the skin may serve as the basis for the development of non-invasive techniques to measure skin antioxidant capacity and also may shed light onto skin related disorders such as vitiligo.