不同增稠载体的过氧化脲漂白剂对釉质表面形态的影响

目的:研究不同载体和浓度的过氧化脲(carbamide peroxide,CP)漂白剂对釉质表面形态的影响。方法:分别以Carbopol、PVP、Poloxamer为凝胶增稠载体,配制含100g/L、150g/L和200g/LCP的CP漂白剂(pH6.5)和不含CP的凝胶制剂,利用近期拔除的离体前牙牙冠分组观察CP漂白剂对釉质表面形态的影响。结果:以Carbopol,PVP或Poloxamer作为增稠载体的漂白剂,随着CP浓度的增高,釉质表面从轻度溶解、脱矿,蜂窝状改变,直至正常釉质层消失,"鱼鳞状"的釉柱结构清晰可辨。其中以Poloxamer为增稠载体的漂白剂较之更甚。结论:以Carbopol,PVP或Poloxamer作为增稠载体的漂白剂,随着CP浓度的增高,釉质表面出现不同程度的形貌改变。     

不同过氧化物对牙釉质结构和硬度的影响

目的:探究30%过氧化氢(hydrogen peroxide,HP)、22%过氧化脲(carbamide peroxide,CP)、3%过硼酸钠(sodium perborate,SP)对离体牙漂白后牙齿釉质表面结构和硬度的差异。方法:筛选正常人离体牙标本并随机分为A、B、C、D 4组,分别用生理盐水、30%过氧化氢、22%过氧化脲、3%过硼酸钠对4组牙齿进行漂白处理,最后对离体牙进行电镜扫描(×2000)和维氏硬度测定并进行统计分析。结果:实验组与对照组相比,扫描电镜显示: 30%过氧化氢和3%过硼酸钠组,其釉质表面呈散在的孔状,蜂窝状破坏,说明牙齿出现了不同程度的脱矿、溶解;22%过氧化脲组牙齿釉质表面结构基本完整,无明显脱矿和溶解现象;硬度测定结果显示:组间两两比较存在差异性(P＜0.05),漂白后4个组牙齿硬度大小是:对照组＞22%过氧化脲组＞3%过硼酸钠＞30%过氧化氢。结论:3种过氧化物漂白试剂中22%过氧化脲对牙釉质结构和硬度的影响最小。     

漂白后牙本质颜色改变对牙齿体部与颈部颜色变化不同的影响研究

目的:探讨漂白后牙齿体部与颈部颜色变化不同的原因。方法:将36个新鲜拔除的人前磨牙沿唇(颊)舌方向中央剖开、去髓,随机分成3组,联合漂白组(A):380 mL/L过氧化氢(HP)45 min/d×1次+150 g/L过氧化脲(CP)8 h/d×4次;诊室漂白组(O):380 mL/L过氧化氢(HP)45 min/d×2次;家庭漂白组(H):150 g/L过氧化脲(CP)8 h/d×14次。3组分别于漂白前、后用Crystaleye电脑比色仪测量牙齿唇(颊)面靠近剖面中线区体部、颈部及相对应剖面靠近釉牙本质界牙本质漂白前后的ΔE值。结果:3种漂白方案疗程结束后,体部、颈部牙齿颜色及与其对应的剖面牙本质均出现了颜色变浅(P﹤0.05),但体部牙齿颜色改变程度超过颈部(P<0.05)。体部、颈部牙本质颜色改变无显著性差异(P>0.05);体部、颈部牙齿表面与其分别对应的剖面牙本质颜色改变无显著性差异(P>0.05)。结论:漂白剂对牙本质的颜色改变不受釉质厚度的影响。牙本质颜色变化和漂白后体部、颈部牙齿表面颜色变化不相关。牙齿体部颜色改变慢于颈部可能是体部釉质厚度大于颈部及半透明性改变产生的。     

过氧化脲漂白剂的体外细胞毒性研究

目的:评价不同增稠载体过氧化脲漂白剂的细胞毒性,并与同类商品漂白剂进行比较.方法:采用琼脂覆盖法通过直径5咖的滤膜圆片,分别评价以Carbopol或PVP为增稠载体的100 g/L、200 g/L过氧化脲漂白剂及同种浓度Opalescence漂白凝胶对L929小鼠成纤维细胞的毒性作用.结果:以Carbopol或PVP为增稠载体的100g/L、200 g/L CP漂白剂和Opalescence 100 g/L、200 g/LCP漂白凝胶的细胞毒性均为2级,中度毒性.结论:不同增稠载体的过氧化脲漂白剂和Opalescence漂白凝胶的细胞毒性没有显著差别.     

氟化物预处理减轻漂白治疗术中牙齿敏感的扫描电镜观察

目的观察氟化物对漂白治疗中牙体硬组织微结构的影响，探讨氟化物用于减轻漂白治疗中牙齿敏感的可行性及其作用机制。方法选取临床因正畸治疗需拔除4颗健康第一前磨牙的患者共12名，按处理方法不同随机分为3组：加氟化钠漂白组、漂白组和空白组。在不同处理后分别制备釉质、牙本质纵剖面和横剖面电镜观察标本，以扫描电镜观察其超微结构改变情况。结果电镜显示漂白组釉质表面出现溶融、脱矿现象；牙本质纵剖面可见管周牙本质轻微脱矿，管间牙本质胶原纤维网架塌陷；横剖面见牙本质小管口因脱矿而呈现不规则，小管径增大。加氟化钠漂白组釉质及牙本质的脱矿程度均减轻，牙本质小管口小于漂白组。结论局部应用氟化钠可减轻釉质表层及牙本质脱矿，降低牙体硬组织通透性，从而缓解漂白过程中所产生的牙齿敏感症状。     

显微硬度体外评估漂白牙膏的防龋效果

目前漂白牙膏的使用越来越普遍，这些牙膏常包含有0．5％～1．5％的过氧化脲作为漂白剂。有研究表明低浓度的过氧化脲对釉质没有明显影响，而高浓度的过氧化脲可造成釉质显微硬度降低、矿物质丢失甚至在釉质表面形成点隙。因此，对于含氟漂白牙膏来说，在漂白牙齿的同时，其防龋效果如何迄今还未见报道。本文的目的是在体外评估含氟漂白牙膏的防龋效果。     

过氧化脲漂白剂对釉质显微硬度影响的实验研究

目的:评价不同载体和浓度的过氧化脲(carbam ide peroxide,CP)漂白剂对釉质表面显微硬度的影响。方法:在18个离体前磨牙的颊、舌面各制备2 mm×2 mm的平面,随机分为6组。分别用卡波姆(Car-bopol)、聚乙烯吡咯烷酮(PVP)或泊洛沙姆(poloxam er)为增稠载体的含11%、21%CP的漂白剂,在37℃100%湿度条件下每天漂白6~8 h,持续2周。漂白前、后测量釉质表面的显微硬度。21%CP治疗组在漂白治疗结束后继续浸入人工唾液2周,再次测量显微硬度。结果:11%CP漂白2周后,釉质的显微硬度与漂白前相比没有显著差异(P>0.05);21%CP漂白2周后,釉质的显微硬度明显低于漂白前(P<0.01),继续浸入人工唾液2周,显微硬度明显高于漂白后(P<0.05),但与漂白前相比仍有显著差异(P<0.05)。在相同CP浓度下,不同增稠载体组间的显微硬度没有显著差异(P>0.05)。结论:11%CP漂白剂对釉质的显微硬度没有影响,21%CP漂白剂可明显降低釉质的显微硬度,人工唾液可在一定程度上增加釉质的再矿化能力,不同的增稠载体对釉质的显微硬度没有明显影响。     

局部应用氟化物对酸蚀釉质作用的体外研究

目的：评价局部应用氟化物对酸蚀釉质的作用。方法：收集正畸减数拔除的年轻前磨牙40个，制备釉质样本，随机分成对照组，lg／L氟化钠液组，含氟牙膏组，联合应用组。用饮料对釉质间断性酸蚀1周，然后使用不同的氟化物处理酸蚀的釉质表面1周。采用显微硬度计检测釉质表面显微硬度值（SMH），原子力显微镜（AFM）、扫描电镜（SEM）观察牙体硬组织表面的结构。结果：饮料浸泡后釉质的SMH明显下降。与对照组相比，氟化物处理后各氟化物处理组的釉质SMH均有明显增加（P＜0．001）。AFM和SEM均可见酸蚀后的釉质表面呈典型的蜂窝状结构，SEM观察显示氟化物处理后，各组釉质表面均有一定沉积物。结论：饮料会导致体外釉质表面的脱矿，氟化物能够促进体外酸蚀釉质的再矿化。     

扫描电镜观察漂白剂对牙釉质和牙本质结构的影响

目的 观察不同浓度漂白剂治疗牙釉质，牙本质超微结构的变化。方法 分别用30%过氧化氢（1）组，16%过氧化脲（2）组，11%过氧化脲（3）组对离体牙牙釉质及牙本质进行6天治疗，SEM下观察。结果 （1）组牙釉质碚矿明显，牙本质因脱矿见有胶原纤维网架显露。（2）组釉质因脱矿晶体微细结构不清晰，牙本质内见有局灶性钙化减低灶。（3）组釉柱排列整齐无脱矿，牙本质内有局灶性钙化减低区。结论 高浓度过氧化氢可使牙釉质及牙本质表层脱矿部分结构遭到破坏，提示临床应用低浓度漂白剂安全有效。     

家庭漂白剂对复合树脂表面粗糙度、显微硬度的影响

目的:评价10%过氧化脲家庭漂白剂对直接和间接复合树脂材料表面粗糙度和显微硬度的影响。方法:实验选用2种直接复合树脂材料(Filtek Z350,Clearfil Majesty Esthetic)和2种间接复合树脂材料(Ceramage,Adoro SR)。每种树脂材料在粗糙度和显微硬度试验中分别制作20个盘形试样(直径10 mm、厚1.0 mm),随机分为10%过氧化脲漂白组和去离子水对照组(n=10)。漂白凝胶处理漂白组试样每天使用8 h,共2周。测量树脂试样漂白处理前、后表面粗糙度和显微硬度值。结果:10%过氧化脲漂白剂处理前后,树脂材料表面粗糙度变化无统计学差异(除外Clearfil Majesty Esthetic)。4种树脂材料漂白前后试样的显微硬度值变化不大,且没有统计学差异。结论:10%过氧化脲漂白剂没有改变树脂材料的显微硬度,但树脂材料表面粗糙度的改变取决于树脂材料的类型。     

柠檬酸致牙釉质脱矿的研究

目的 观察10%柠檬酸酸蚀牙釉质不同时间的效果,以获得研究早期釉质龋的可靠体外实验模型,探索更高效的牙釉质脱矿实验方法.方法 选取离体人恒前磨牙切割制成牙釉质块,经10%柠檬酸及部分饱和酸缓冲脱矿系统脱矿,扫描电镜观察牙釉质表面经柠檬酸酸蚀不同时间(90 s、120 s、150 s)及部分饱和酸缓冲脱矿系统脱矿1周后的形态学特征,并用显微硬度计检测标本脱矿前后表面显微硬度.结果 牙釉质进行脱矿处理后,釉质表面呈现酸蚀状外观.酸蚀90 s时,仅见小部分釉柱晶格脱矿溶解,脱矿牙釉质的能力有限;酸蚀120 s时,与早期自然龋损近似,呈蜂窝状;酸蚀150 s时,牙釉质表面呈酸蚀样破坏形貌,属于过度酸蚀;而部分饱和酸缓冲脱矿系统脱矿效果相对较差.结论 柠檬酸具有较强的酸蚀作用,其脱矿牙釉质的能力随着时间的延长而增强,10%的柠檬酸酸蚀120 s可获得早期釉质龋模型.     

黄瓜籽醇提取物对早期釉质龋再矿化的影响

目的:研究不同浓度黄瓜籽醇提取物对人工脱矿釉质龋再矿化的影响。方法:将牛切牙在pH=5.0的脱矿溶液中,形成人工脱矿釉质龋模型,选取脱矿后硬度在280 HV的脱矿牛切牙,随机分为5组:20 g/L氟化钠(NaF)组(阳性对照组)、去离子水组(阴性对照组)、2、10、20 g/L黄瓜籽醇提取物组,用显微硬度仪测试不同溶液处理后脱矿釉质表面的硬度值进行比较。电子探针观察表面形态并进行主要元素分析。结果:脱矿釉质表面经不同浓度黄瓜籽醇提取物和NaF再矿化处理后,各组釉质显微硬度较再矿化前明显增高(P<0.05),去离子水组再矿化前后无明显差异(P>0.05)。显微硬度值随黄瓜籽醇提取物浓度增加而增加,各组组间比较差异有统计学意义(P<0.05)。电子探针结果显示,去离子水组表面釉质呈典型的脱矿釉质表现,为蜂窝状疏松结构,NaF组可形成紧密球形均匀的沉淀区,黄瓜籽醇提取物组可见不规则沉积物覆盖脱矿的蜂窝状结构,且随浓度升高,沉积物由疏松转为致密。结论:NaF促进早期釉质再矿化的效果最好。黄瓜籽醇提取物对早期釉质龋有再矿化作用,作用效果随浓度升高而增强。     

镧、钙、氟对釉质脱矿的影响——显微硬度测定

目的 :比较镧、钙、氟对人牙釉质酸蚀脱矿影响 ,为镧的应用研究提供实验依据。方法 :酸性凝胶化学致龋 ,测定釉质脱矿区剖面显微硬度 ,逐点单因素方差分析其显微硬度值。结果 :釉质表层下 2 5～ 15 0 μm范围内 ,镧处理组、氟处理组的硬度值高于对照组 ;2 5～ 75 μm范围内 ,镧处理组的硬度值高于钙处理组 ;5 0～ 15 0 μm范围内 ,钙处理组的硬度值高于对照组 ,氟处理组的硬度值高于镧处理组。结论 :脱矿凝胶中加入 1g/L的Ca2 +、La3 +、F-均阻止釉质硬度的下降 ,氟的作用最强 ,钙的作用最弱 ,镧的作用界于氟和钙之间。     

Effect of home bleaching agents on the roughness and surface morphology of human enamel and dentine

AIMS: Carbamide peroxide (CP) containing bleaching agents are now widely used in different concentrations. In this study, the effect of 10% and 15% CP containing home bleaching agents on the surface roughness and morphology of human enamel and dentine were evaluated in vitro. METHODS: 90 non-carious human mandibular incisors were divided randomly into two equal groups (enamel and dentine). The dentine group specimens were ground to expose dentine surfaces. The samples in both groups were then randomly divided into three main groups and then divided into three subgroups, according to bleaching application times (n=15). The samples in both enamel and dentine groups were treated with 10% CP at Group 1 and 4, 15% CP at Group 2 and 5 and distilled water at Group 3 and 6. The surface roughness of the samples was analysed before bleaching (1a, 2a, 3a for enamel, 4a, 5a, 6a for dentine), after 4hr (1b, 2b, 3b for enamel, 4b, 5b, 6b for dentine) and after 28hr of bleaching application (1c, 2c, 3c for enamel, 4c, 5c, 6c for dentine) using a computerised roughness tester. The surface morphologies of treated and control specimens were also examined by SEM. RESULTS: There were no statistically significant differences between the surface roughness of untreated control specimens and the specimens treated with the bleaching materials (10% and 15% CP) for both enamel and dentine at any given measurement time (p>0.05). CONCLUSION: Under the careful guidance of a dentist, home bleaching can be thought a reliable treatment for both stained enamel and dentine, regardless of whether 10% or 15% CP is used.     

激光照射与酸性氟磷酸盐联合应用对离体人牙齿釉质脱矿的影响

目的 :研究激光照射及酸性氟磷酸盐 (acidulatedphosphatefluoride ,APF)处理离体人牙齿釉质 ,对牙釉质抗酸性的影响。方法 :10 0、15 0、2 0 0mJ 3种能量的激光照射光滑面及咬合面牙釉质后用 12 .3g/LAPF处理 ,对照组仅用 12 .3g/LAPF处理。将处理过的牙齿置于人工龋液中脱矿 ,测量不同时间后脱矿液中的釉质钙溶出量 ;偏光显微镜下测量人工龋的深度。结果 :酸蚀 10h后 ,实验组釉质钙溶出量少于对照组 (P <0 .0 5 ) ;酸蚀 2 4h后各组之间的钙溶出量无显著的统计学差异 (P >0 .0 5 )。 10 0mJ激光照射咬合面组的人工龋损深度少于其他 3组 (P <0 .0 5 ) ,但 15 0、2 0 0mJ激光照射组与对照组相比无显著的统计学意义 (P >0 .0 5 )。结论 :10 0mJ激光照射后再使用 12 .3g/LAPF可明显增强光滑面及咬合面牙釉质的抗酸性     

SEM evaluation of contemporary self-etching primers applied to ground and unground enamel

PURPOSE: This study evaluated the etching effect of self-etching priming agents applied to intact and ground enamel. MATERIALS AND METHODS: Thirty-two human molars were used. Each tooth was divided into two halves. The buccal or lingual mid-coronal surface of 32 half-teeth was ground with 600-grit silicon carbide paper. The other half-teeth were left intact (control). Teeth were treated with Clearfil SE Bond (SE), Prompt L-Pop (PLP) or Adper (AD). Those in the control group were etched with 35% phosphoric acid. The etching effect of such systems on enamel surfaces was assessed by three different approaches using scanning electron microscopy: 1) in situ or direct morphological examination of the etched enamel; 2) indirect morphological examination, that is, evaluation of the etching pattern left on resin reproductions; 3) adhesive interface examination. RESULTS: SE exhibited the least aggressive dissolution of the intact and ground enamel, with many sites of the intact enamel remaining completely unetched. SE monomer infiltration into etched enamel was restricted to the superficial layer. PLP and AD produced equivalent etching patterns on intact and ground enamel, which resemble that produced by the phosphoric acid control group. PLP and AD monomer penetration extended along the porous subsurface enamel layer. CONCLUSION: SE produced mild morphological changes on intact and ground enamel surface, resulting in a very superficial resin infiltration particularly into intact enamel. No differences were evident among the etching and resin infiltration pattern produced by both all-in-one self-etching adhesives, PLP and AD, and the phosphoric acid system.     

aggressiveness of contemporary self-etching adhesives part ii. etching effects on unground enamel

Objective : The purpose of this study was to investigate the etching efficacy of three self‐etching primers on unground enamel by (1) examining the etched surface using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and (2) evaluating the microtensile bond strengths of these self‐etching primers to unground enamel using either their manufacturers' adhesive or a control resin. Materials and Methods : Three self‐etching systems were evaluated in this study: Clearfil® SE Bond (Kuraray Co. Ltd, Osaka, Japan), Non‐Rinse Conditioner® (NRC; Dentsply DeTrey, Konstanz, Germany), and Prompt L‐Pop® (ESPE, Seefeld, Germany). All‐Bond® 2 (Bisco Inc., Schaumburg, IL, USA), a total‐etch adhesive system, was used as a control. Buccal surfaces of human bicuspids were conditioned using either a self‐etching primer or 32% phosphoric acid for SEM examination of the conditioned enamel. The self‐etching materials were rinsed with an ascending series of ethanol. For TEM examination, each adhesive system was used according to its manufacturer's instructions. Unground enamel treated with NRC was bonded using Prime & Bond NT® (Dentsply DeTrey). Uninfiltrated enamel was then completely dissolved, and resininfiltrated replicas were assessed for the extent of penetration of the adhesives into the enamel. For microtensile bond strength evaluation, specimens were assigned to two groups. The first group was conditioned and bonded according to each manufacturer's instructions. In the second group the conditioned enamel surfaces were rinsed with ethanol to remove the self‐etch primer and then were primed and bonded using the control primer and resin adhesive. Resin composite (Z100®, 3M ESPE, St. Paul, MN, USA) was applied in 2 mm increments. The first resin composite increment was light‐cured using the pulse delay technique, followed by conventional light‐activation of subsequent increments. Specimens were sectioned into uniform 0.96 mm² beams and were subjected to tensile stress until failure. Results : The etching pattern and the subsurface hybrid layer morphology revealed by SEM and TEM varied by system. Clearfil SE Bond had the mildest etching pattern, whereas Prompt L‐Pop had an etching pattern similar to that of 32% phosphoric acid. When adhesive systems were used as directed, the mean microtensile bond strengths of the three self‐etching adhesive systems were not significantly different from one another, but they were significantly lower than that of the control group (10–14 MPa vs 27 MPa). When bonding specimens with the control adhesive resin, the mean microtensile bond strengths of NRC with Prime & Bond NT and Prompt L‐Pop were not significantly different from those of the control group, but all were significantly higher than that of Clearfil Mega SE Bond. Conclusions : The self‐etching primers evaluated in this study had significantly lower microtensile bond strengths to unground enamel than did a total‐etch system. There was no relationship between the etching efficacy of the adhesive systems and the microtensile bond strength.     

Er:YAG激光预备对牙釉质表面性能及树脂粘结强度的影响

目的:探讨Er:YAG激光预备对牙釉质表面性能及树脂粘结强度的影响。方法:选取50颗无龋坏、无充填物的人离体前磨牙或磨牙,用涡轮手机按近远中方向将离体牙切割成颊/舌两部分,最终选取84个样件,按不同的表面处理方法随机分为7组(A-G组),每组12个样件。每组2个样件扫描电镜观察,其余10个样件分别在处理后的牙釉质表面粘结光固化复合树脂,进行剪切强度测试。结果:A组剪切强度最高(20.51±3.33) MPa。B、C、D组剪切强度次之,与A组比差异无统计学意义。E、F、G组剪切强度较弱,其中E组剪切强度与B、C、D组无显著差异,F、G组与其他组有显著差异。扫描电镜观察:随着激光能量的增加,牙釉质表面粗糙度增加。激光处理后再进行酸蚀处理,牙釉质表面整体结构均匀,釉柱结构清晰可见,无玷污层。结论:Er:YAG激光处理牙釉质表面不能达到类似酸蚀的效果。激光加酸蚀能达到类似酸蚀的效果。牙釉质剪切粘结强度随着激光能量的增加而增加。[关键词] Er:YAG激光 酸蚀 牙釉质 剪切粘结强度     

MTAD根管冲洗液对牙本质、牙釉质微硬度影响的研究

目的:评价MTAD根管冲洗液对牙本质、牙釉质微硬度的影响。方法:收集新鲜完整的前磨牙48个,截取牙冠并沿牙体长轴剖开,分别用30mL/L过氧化氢液、50g/L次氯酸钠液、MTAD液、13g/L次氯酸钠液处理牙本质、牙釉质5、15min,采用微硬度测定仪测定处理前、后两个时间点上牙本质、牙釉质的微硬度。结果:与30mL/L过氧化氢液和50g/L次氯酸钠液相比,使用MTAD液和13g/L次氯酸钠液处理后的牙本质、牙釉质微硬度的降低幅度不明显。结论:通过与30mL/L过氧化氢液、50g/L次氯酸钠液的对比研究发现,MTAD冲洗液对牙本质、牙釉质微硬度的影响明显小于前两者, 13g/L次氯酸钠冲洗液的影响与MTAD的相似,MTAD液联合13g/L次氯酸钠液的根管冲洗方法值得推荐。