过氧化氢酶对外漂白后树脂充填体边缘微渗漏的影响

目的： 观察过氧化氢酶对10%过氧化脲外漂白后复合树脂充填体边缘微渗漏的影响。方法： 选取牙体健康完整的人离体前磨牙40颗,随机分为4组,第1组不漂白直接进行树脂充填,第2组外漂白后立即树脂充填,第3组外漂白后将牙在人工唾液中浸泡3周再进行树脂充填,第4组外漂白后先用过氧化氢酶处理窝洞再进行树脂充填。然后将4组样本进行2000个周期的冷热循环,应用2%亚甲基蓝染色24 h,体视显微镜下观察剖面树脂充填体的微渗漏程度,采用SPSS17.0软件包对数据进行统计学分析。结果： 第1组微渗漏值最低,第2组微渗漏值最高,第3组微渗漏值显著高于第1组但与第2组相比无显著差异（P>0.05）;第4组微渗漏值较第2组显著下降（P<0.05）。结论： 10%过氧化脲外漂白致树脂充填体边缘微渗漏明显增加,树脂充填前应用过氧化氢酶处理窝洞,可有效减少微渗漏,延迟充填不能有效改善微渗漏。     

两种抗氧化剂凝胶对内漂白后充填树脂微渗漏的影响

目的:对比含表面活化剂(0.2%Tween 80)的10%抗坏血酸钠(sodium ascorbate, SA)凝胶和6.5%原花青素(proanthocyanidins, PC)凝胶对死髓牙内漂后充填树脂微渗漏的影响,以及确定最佳处理时间。方法:收集近1月拔除的离体前磨牙120颗,随机分为10组(n=12), A组：未漂白组,B组：漂白组,C组：含0.2%Tween 80的10%SA组,D组：6.5%PC组,C/D组根据内漂白后抗氧化剂处理时间不同(10、30、60、120 min)又分为4个亚组(C1/C2/C3/C4,D1/D2/D3/D4),各组处理后行树脂充填窝洞。所有样本经过冷热循环后,每组随机选取10个样本置于2%亚甲基蓝染色,在体式显微镜下观察树脂与洞壁粘接界面微渗漏的程度,并对测量结果进行统计学分析。每组剩余两个样本于扫描电镜下观察牙体组织与充填树脂粘接界面的微观形貌特点。结果:A组微渗漏值明显小于B组(P=0.000),各实验组与B组比较差异均有统计学意义(P<0.05),C组微渗漏值逐渐减小,D3组微渗漏值最小,C/D组间除C4/D4外其余均有统计学差异(P...     

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。     

漂白剂对玻璃离子水门汀类材料充填Ⅴ类洞边缘微渗漏的影响

目的评估漂白凝胶和洁白牙贴对3种不同的玻璃离子水门汀类材料边缘微渗漏的影响。方法在45颗离体健康前磨牙的颊舌侧制备Ⅴ类洞,随机分为A、B、C组,分别使用加强型玻璃离子水门汀KetacTM Molar Easymix、复合体F2000、复合体Dyract AP充填,每个大组再分为3个亚组,第1组和第2组分别使用质量分数14％过氧化氢（HP）洁白牙贴和10％过氧化脲（CP）凝胶进行漂白,第3组为对照组。所有样本置入37 ℃蒸馏水中保存7 d后冷热循环500次,然后进行漂白。漂白21 d后置于碱性品红溶液中染色24 h,沿牙体长轴通过充填体中央颊舌向剖开牙齿,体视显微镜下观察并测量染料渗入窝洞壁的深度。结果2种漂白方式对充填体边缘微渗漏的影响没有明显差异（P>0.05）;与对照组相比,2种漂白方式对B、C组的微渗漏均没有产生明显影响（P>0.05）,但均可使A组的微渗漏增加（P<0.05）。结论10％CP凝胶和14％HP洁白牙贴对充填体边缘微渗漏的影响无明显差异;漂白不会影响复合体的微渗漏,但会增加加强型玻璃离子水门汀的微渗漏。     

漂白处理对树脂充填体边缘微渗漏的影响

目的:评价35%过氧化氢凝胶对树脂充填体边缘微渗漏的影响。方法:选择离体上颌第三磨牙40颗,在颊面制备Ⅴ类洞复合树脂分层充填,光照固化抛光后按处理时间随机分为4组(n=10):A(对照组)、B(10 min)、C(20 min)、D(30min)。将凝胶涂布于充填体表面进行漂白处理后冷热循环500次,再用2%亚甲蓝溶液染色24 h,沿颊舌纵向剖开,体式显微镜观察并记录染料渗入深度。用Kruskal-Wallis法进行数据分析;Mann-Whitney法组间两两比较,检验水准均为α=0.05。结果:不同漂白处理时间对树脂充填体边缘微渗漏的影响有统计学意义(P<0.05);组间比较显示A与C、A与D、B与D、C与D间差异有统计学意义。结论:35%过氧化氢凝胶漂白处理使复合树脂充填体的边缘微渗漏程度增加。     

暂封材料对窝洞充填后微渗漏影响的实验研究

目的：研究暂封材料对复合树脂充填后微渗漏的影响,探讨减少微渗漏的方法。方法：60颗离体牙备Ⅰ类洞后随机分为三组。A、B组为实验组,用氧化锌丁香油粘固剂暂封1周,超声波清洗去除暂封材料,A组再用气水枪冲洗、B组再用75%酒精擦拭及气水枪冲洗。然后用光固化树脂充填窝洞;C组为对照组,不暂封窝洞而直接进行光固化树脂充填。用染色法制备微渗漏检测标本,测量比较各组充填后的微渗漏情况。结果：A组微渗漏大于B组和C组（P〈0.05）,B组和C组间无统计学差异（P〉0.05）。结论：暂封材料残留有增加充填后微渗漏的可能性;超声波清洗后用75%酒精擦拭洞壁可以有效地减少微渗漏的发生及微渗漏程度。     

体外模型中3种光固化树脂充填体边缘微渗漏实验研究

目的：比较3种光固化充填材料在体外模型中充填体边缘的微渗漏程度。方法：在36颗离体的前磨牙颊侧颈部备洞。随机分为3组,每组12颗牙。分别充填3M前后牙通用树脂Valux Plus、流动性纳米复合树脂Z350、登士柏Esthet.XTM复合树脂。样本经温度循环,采用10g/L碱性品红染色后,颊舌向沿长轴连续切开,在体式显微镜下观察修复体与牙体洞壁间染料渗漏情况。结果：3种材料中流动性纳米复合树脂Z350微渗漏最小。前后牙通用树脂Valux Plus微渗漏最大。流动性纳米复合树脂Z350与其他两组相比有显著性差异（P〈0.01）。结论：流动性纳米复合树脂Z350是临床上充填颊侧颈部窝洞的较好材料。     

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目的对比4种充填材料的边缘微渗漏情况,为其临床应用提供合理指导。方法选择2013年1—6月青岛大学医学院附属医院口腔科因牙周病或阻生齿而拔除的健康新鲜后牙60颗,备洞后随机分为6组,每组10颗,分别使用Fihek Z250复合树脂（A1、A2组）、Ketac N100树脂加强型玻璃离子（B1组）、Ketac MolarEasymix型玻璃离子（B2、B3组）、F2000Compomer玻璃离子复合体（B4组）充填窝洞。其中A2组充填后充填体表面涂布AdperSingleBond2粘接剂,B3组充填后充填体表面涂布凡士林,而其他各组充填后表面不做任何处理。经冷热交替实验后,记录各组染料渗入窝洞壁与充填体之间的深度,并进行统计分析。结果A2组微渗漏最小,B2组微渗漏最大,与其他组（A1、B1、B3、B4）相比差异有统计学意义（P〈0．05）;A1、B1、B3、B4组间两两比较差异均无统计学意义（P〉0．05）。结论复合树脂、树脂加强型玻璃离子、玻璃离子复合体的边缘微渗漏均小于传统型玻璃离子;表面涂布隔湿剂后能增强上述材料的边缘封闭性能。     

原花青素对漂白后牙本质与复合树脂粘接强度的影响

目的 探讨原花青素对过氧化脲漂白后牙本质与复合树脂粘接强度的影响。方法 按照牙本质粘接界面不同处理方法,将120颗人离体第三磨牙随机分为12组(n=10);W组(无漂白+去离子水)、Wa组(无漂白+去离子水+老化)、WT1组(无漂白+5%原花青素1 min)、WT1a组(无漂白+5%原花青素1 min+老化)、WT2组(无漂白+5%原花青素5 min)、WT2a组(无漂白+5%原花青素5 min+老化)、C组(过氧化脲+去离子水)、Ca组(过氧化脲+去离子水+老化)、CT1组(过氧化脲+5%原花青素1 min)、CT1a组(过氧化脲+5%原花青素1 min+老化)、CT2组(过氧化脲+5%原花青素5 min)、CT2a组(过氧化脲+5%原花青素5 min+老化);上述各组在即刻或冷热循环老化后,万能力学试验机测试粘接强度,扫描电镜观察粘接界面微观形貌和纳米渗漏。结果 CT1组经原花青素处理1 min(P<0.001)和CT2组经原花青素处理5 min(P<0.001)的漂白即刻组粘接强度均高于对照组C组,差异具有统计学意义,但CT1与CT2之间差异无统计学意义(P=1.00...     

Micro CT评估光照模式对复合树脂微渗漏影响的研究

目的:用Micro CT评价不同光照模式对复合树脂充填体微渗漏的影响。方法:选取24颗新鲜拔除的上颌前磨牙,在牙冠颊面制备圆形窝洞(直径1 mm,深度1 mm),窝洞用光固化树脂(3M Z250)充填并固化,按照光固化模式随机分为常规模式组(A组)、弱光引导组(B组)、间歇光照组(C组)。标本经冷热循环及氨硝酸银染色剂浸染后,用Micro CT测量复合树脂充填体和牙齿界面的银沉积物体积,定量评价微渗漏程度。结果:常规模式组微渗漏大于弱光启动组和间歇光照组,差异有显著性(P<0.05);弱光启动组与间歇光照组之间微渗漏有差异,但不具统计学意义(P>0.05)。结论:弱光引导模式和间歇光照模式能够比常规光照模式更有效降低复合树脂(3M Z250)的微渗漏。     

Effect of nonvital bleaching with 10% carbamide peroxide on sealing ability of resin composite restorations

AIM: To (i) determine the effect of nonvital bleaching with 10% carbamide peroxide on the sealing ability of resin composite restorations bonded with a self-etching adhesive system; and (ii) compare the effects of antioxidant treatment and delayed restoration after bleaching on marginal seal. METHODOLOGY: Forty-eight noncarious maxillary incisors were divided into four groups (n=12) after conventional root canal treatment was completed. In group 1, access cavities were restored with a self-etching adhesive system and resin composite. In the remaining three groups, 10% carbamide peroxide bleaching gel was placed into the access cavities for periods of 8 h per day for 1 week. They were then restored in the same manner as group 1. Group 2 consisted of specimens restored immediately after bleaching. Group 3 specimens were treated with the antioxidant, 10% sodium ascorbate, whereas group 4 specimens were immersed in artificial saliva for 1 week before restoration. Ten specimens in each group were then subjected to dye leakage; the remaining 2 specimens were examined in a SEM (Jeol/JSM 5200, Tokyo, Japan). The dye penetration was assessed with the standard scoring system. Statistical analysis was carried out using the Kruskal-Wallis and the Mann-Whitney tests. RESULTS: Groups 1, 3 and 4 exhibited similar leakage patterns and significantly less leakage than group 2 (P<0.0083). SEM examination of groups 1, 3 and 4 specimens demonstrated close adaptation of resin composite to cavity walls, whereas group 2 specimens did not. CONCLUSION: Nonvital bleaching with 10% carbamide peroxide adversely affected the immediate sealing ability of resin composite restoration; both 10% sodium ascorbate treatment and a 1-week delay in restoration following bleaching improved the reduced sealing ability of resin composite.     

Effect of pine bark extract on bond strength of brackets bonded to bleached human tooth enamel

Abstract

Aim. The purpose was to investigate the effect of pine bark (proanthocyanidin, natural antioxidant) solution on the shear bond strength (SBS) of metal brackets bonded with composite resin to human enamel after bleaching with hydrogen peroxide (HP). Materials and methods. Sixty recently extracted premolars were divided into an experimental group (n = 45), which was bleached with 40% HP, and a control group (n = 15), which was not bleached. The experimental group was further divided into three sub-groups. Specimens in group IB (n = 15) were bonded immediately after bleaching; specimens in group SA (n = 15) were bleached, then treated with 10% sodium ascorbate and then bonded; group PB specimens (n = 15) were bleached, then treated with 5% pine bark solution and bonded. The specimens were debonded with Universal testing machine. The adhesive remnant index was calculated. Results. No significant differences in shear bond strength were noted when the pine bark treated group was compared with the control group and sodium ascorbate group (p > 0.05). Treating the bleached enamel surface with 10% sodium ascorbate or 5% pine bark solution reverses the SBS reduction. Conclusion. So, as a natural antioxidant and less hazardous, clinicians can choose pine bark solution instead of sodium ascorbate.     

Nd:YAG激光对不同充填材料牙本质边缘微渗漏的影响

目的 评价Nd:YAG激光对不同充填材料与牙本质之间边缘微渗漏的影响。方法 选用人离体前磨牙36颗,制备V类洞,随机分为激光组和对照组,激光组使用80 rnJ、10 Hz脉冲Nd:YAG激光照射后,分别用全酸蚀粘接树脂、自酸蚀粘接树脂和玻璃离子充填洞型,对照组不使用激光,同样用如前所述的3种材料充填洞型。将所有标本浸泡在2%亚甲基蓝溶液中24 h后,用金刚砂片从颊舌向通过充填物中央纵向切开牙体,显微镜下观察龈壁染料渗透的深度。采用SAS8.0软件对数据进行统计学处理。结果 经Nd:YAG激光照射后尽管3种材料与牙本质之间微渗漏程度均有降低趋势,但只有玻璃离子组激光照射后较未照射组微渗漏降低具有统计学意义(P<0.05)。结论 脉冲Nd:YAG激光照射牙本质壁,在一定程度上可能会减少玻璃离子充填材料与洞壁的微渗漏。     

Postoperative dental bleaching: effect of microleakage on Class V tooth colored restorative materials

The effect of 3 percent, 11 percent, and 16 percent carbamide peroxide bleaching solutions and 35 percent hydrogen peroxide bleaching gel on microleakage of Class V composite resins, resin modified glass ionomer cements, and compomer restorative materials together with corresponding (if indicated) fourth/fifth generation bonding agents was evaluated using previously extracted human teeth. Five groups of Class V cavity preparations were placed in enamel of the facial surfaces of 200 teeth. Groups A through D included 40 restorations each (4 different restorative materials and their accompanying bonding agent multiplied by 10 teeth) treated with 3 percent, 11 percent, and 16 percent carbamide peroxide bleach and 35 percent hydrogen peroxide bleach. Group E included 40 restorations without treatment of bleach and stood as the control. The restorative materials included were: Fuji II LC resin modified glass ionomer cement, Helioprogress composite resin/-Heliobond adhesive system, Aelitefil composite resin/Allbond 2 adhesive and Dyract compomer material/Prime & Bond adhesive system. Bleaching agents included were Rembrandt 3 percent peroxide gel, Perfecta 16 percent carbamide peroxide gel, White & Brite 11 percent carbamide peroxide solution and Superoxyl 35 percent hydrogen peroxide gel. All teeth were thermally stressed for 100 cycles and microleakage were assessed by dye penetration. The results were tabulated using Analysis of Variance (ANOVA) testing procedures. The Aelitefil composite resin material behaved the least favorably (relative to microleakage) compared to the other materials when exposed to various concentrations of dental bleaching agents.     

Effect of 10% sodium ascorbate on the shear bond strength of composite resin to bleached bovine enamel

The purpose of this study was to comparatively investigate the effect of antioxidant treatment and delayed bonding after bleaching with three different concentrations of carbamide peroxide (CP) on the shear bond strength of composite resin to enamel. One hundred flat buccal enamel surfaces obtained from bovine incisors were divided into three bleaching groups of 10, 16 and 22% CP (n = 30) and a control group. Each bleaching group was then divided into three subgroups (n = 10). Group 1 consisted of specimens bonded immediately after bleaching. Group 2 specimens were treated with antioxidant agent, 10% sodium ascorbate, while Group 3 specimens were immersed in artificial saliva for 1 week after bleaching. Specimens in the control group were not bleached. After the specimens were bonded with Clearfil SE Bond and Clearfil AP-X, they were thermocycled and tested in shear until failure. Fracture analysis of the bonded enamel surface was performed using scanning electron microscope. The shear bond strength data was subjected to one-way analysis of variance followed by Duncan's multiple range test at a significance level of P < 0.05. Shear bond strength of composite resin to enamel that was bonded immediately after bleaching with 10, 16 and 22% CP was significantly lower than that of unbleached enamel (P < 0.05). For all three bleaching groups, when the antioxidant-treated and delayed bonding (1 week) subgroups were compared with the control group, no statistically significant differences in shear bond strength were noted (P < 0.05).     

The effectiveness of four methods for stain removal from direct resin-based composite restorative materials

Background/purposeFew studies investigated the best method for removing stains from different types of resin-based composite restorations and compared them to the more recently introduced nanocomposites. This study compared the effect of four methods for stain removal from composite resins; finishing with Sof-lex disks, using pumice and brush, bleaching with 10% carbamide peroxide and 38% hydrogen peroxide.Materials and methodsTwenty disk specimens were prepared. Specimens were immersed in a staining solution for 3 weeks. The stained surfaces of five specimens from each RBC material were treated with one of the treatment procedures. Colorimetric measurements were taken using spectrophotometer prior to and after staining, and then repeated after surface treatments. Color difference values were calculated.ResultsOne-way ANOVA indicated significant differences in color change of the three composite resin materials following staining. Filtek Z250 showed the least susceptibility to discoloration followed by Renamel, Filtek Supreme was the material most prone to discoloration. Two-way ANOVA and Tukey’s Post Hoc showed that all stain removing procedures except polishing with pumice, were able to return Filtek Z250 to clinically acceptable color difference. While bleaching with 38% carbamide peroxide was not effective with Renamel. Only pumice and 10% carbamide peroxide were able to return Renamel to clinically acceptable color difference.ConclusionCompositions of resin-based composite resins play an important role in their susceptibility to stain and their amenability to stain removal procedures. Home bleaching showed good results for the three materials, while office bleach was the least effective.     

Effect of antioxidant treatment on bond strength of a luting resin to bleached enamel

PURPOSE: The aim of this study was to comparatively investigate the effect of antioxidant treatment and delayed bonding after bleaching with carbamide peroxide on the shear bond strength (SBS) of a luting resin to enamel. MATERIALS AND METHODS: Forty flat enamel surfaces were prepared from freshly extracted human molars using a low speed diamond saw, then divided into three bleaching groups (n=10/group) and a control group (n=10). Group 1 consisted of specimens bonded immediately after bleaching. Group 2 specimens were treated with an antioxidant agent, 10% sodium ascorbate, while Group 3 specimens were immersed in artificial saliva for 1 week after bleaching. Specimens in Group 4 were not bleached, but immersed in artificial saliva for 1 week before bonding. Forty ceramic blocks (Empress 2, Ivoclar) were prepared and luted to teeth using a dual-curing resin cement (Variolink II, Ivoclar). The specimens were thermocycled and the SBS tests were performed using a universal testing machine (crosshead speed: 0.5mm/min). Fracture analysis of the bonded surfaces was done using a scanning electron microscope. Statistical analysis was carried out by Kruskall-Wallis and Mann-Whitney U-tests. RESULTS: While the samples that were immediately bonded after bleaching (Group I) demonstrated significantly lower shear bond strengths and 10% sodium ascorbate group (Group II) demonstrated significantly higher bond strengths than control group samples (p<0.05), no significant differences were found among delayed bonded group and control group (p>0.05). CONCLUSION: Using sodium ascorbate with a concentration of 10% may be reliable for reversing the compromised bond strength.     

Reversal of compromised bonding in bleached enamel

Oxygen inhibits polymerization of resin-based materials. We hypothesized that compromised bonding to bleached enamel can be reversed with sodium ascorbate, an anti-oxidant. Sandblasted human enamel specimens were treated with distilled water (control) and 10% carbamide peroxide gel with or without further treatment with 10% sodium ascorbate. They were bonded with Single Bond (3M-ESPE) or Prime&Bond NT (Dentsply DeTrey) and restored with a composite. Specimens were prepared for microtensile bond testing and transmission electron microscopy after immersion in ammoniacal silver nitrate for nanoleakage evaluation. Bond strengths of both adhesives were reduced after bleaching but were reversed following sodium ascorbate treatment (P < 0.001). Resin-enamel interfaces in bleached enamel exhibited more extensive nanoleakage in the form of isolated silver grains and bubble-like silver deposits. Reduction of resin-enamel bond strength in bleached etched enamel is likely to be caused by a delayed release of oxygen that affects the polymerization of resin components.     

The effect of hydrogel and solution of sodium ascorbate on bond strength in bleached enamel

Compromised bonding to bleached enamel can be reversed with sodium ascorbate as an antioxidant. This study evaluated the effect of hydrogel and solution of sodium ascorbate on enamel-resin composite shear bond strength after bleaching. Sixty buccal enamel surfaces obtained from human, sound third molars were randomly divided into 4 groups (n=15). Enamel surfaces were subjected to different treatments: 1) bleaching (10% carbamide peroxide gel); 2) bleaching + 10% sodium ascorbate solution; 3) bleaching + 10% sodium ascorbate hydrogel and 4) bleaching + 20% sodium ascorbate hydrogel. The specimens were bonded with Single Bond and restored with a composite. The specimens were prepared for shear bond testing. The data was evaluated using ANOVA and Tukey tests. Bond strengths were significantly increased following hydrogel and solution of sodium ascorbate treatments (p<0.05). Also, there was no significant difference among the different forms of sodium ascorbate preparations.