固化光源光照角度对牙本质粘结强度的影响

目的：通过改变发光二极管光固化灯光照角度研究复合树脂固化后牙本质粘结强度。方法：选取因正畸需要拔除的前磨牙20颗,随机分成4组。去除面釉质,暴露平的牙本质表面,酸蚀后涂布粘结剂。发光二极管光固化灯固化粘结剂20s,复合树脂堆砌树脂冠,高2mm。A组：发光二极管光固化灯光导棒与树脂粘结面成30°光照。B组：成45°光照。C组：成60°光照。D：成90°光照。4组均光照30s。用硬组织切片机将实验牙切成粘结面积约为1mm×1mm的柱状小条,将样本放置于微拉伸测试仪上,测试髓壁的牙本质粘结强度。结果：发光二极管光固化灯投照角度为30°时,牙本质粘结强度最大（P〈0.05）。结论：固化光源投照角度对牙本质粘结强度有影响,随着角度增加微拉伸粘结强度呈降低趋势。     

固化光源对充填体与牙体密合度影响的实验研究

目的:研究两种固化光源固化同一种复合树脂充填体与牙体的密合度.方法:选取20颗离体前磨牙,采用析因设计随机分成10组,在颊面牙颈部制备Ⅴ类洞,使用卤素光固化灯和发光二极管光固化灯固化粘结剂20 s后,分别固化树脂20 s、30 s、40 s、50 s和60 s.将实验牙置于(37±1) ℃人工唾液中浸泡24 h后,置于(37±1) ℃恒温水浴箱内24 h后取出.使用扫描电镜观察牙合壁和龈壁处充填体与牙体的密合度并进行统计学分析.结果:固化粘结剂和树脂使用的光源及固化树脂使用的时间两者之间存在交互作用,差异有显著的统计学意义(P<0.01).10组中缝隙宽度最小均值为0.765 μm,出现在使用LED光固化灯固化粘结剂20 s,LED光固化灯固化树脂30秒组.结论:固化光源可影响充填体与牙体的密合度.适宜的固化时间可使充填体与牙体的密合度增加,固化时间过长或过短均会影响密合度.本研究显示使用发光二极管光固化灯固化粘结剂20 s,发光二极管光固化灯固化树脂30 s时充填体与牙体的密合度最好.     

粘结剂使用方式对全酸蚀树脂水门汀与牙本质粘结性能影响的研究

目的评价粘结剂的3种不同使用方式（不使用粘结剂,粘结剂不固化及粘结剂固化10 s）对全酸蚀树脂水门汀与牙本质间粘结性能的影响。方法新鲜拔除的无龋人第三磨牙45颗,随机分为9组（n=5）,流水降温下磨除冠部牙釉质,制备标准牙本质粘结面,酸蚀冲洗后表面按全酸蚀粘结技术处理,牙本质粘结剂处理方式按设计进行,然后与3种全酸蚀树脂水门汀（Rely X ARC、Calibra、VariolinkⅡ）粘结并测试微拉伸粘结强度,用扫描电镜观察粘结界面。结果对于3种全酸蚀树脂水门汀,不使用粘结剂组未测得粘结强度;粘结剂不固化组及粘结剂固化10 s组均获得较为满意的粘结强度,不固化组的微拉伸粘结强度（15.534±2.099;22.827±6.968;10.736±3.199）显著高于粘结剂固化10 s组（13.476±2.710;14.076±5.165;7.736±3.052）（P〈0.05）。结论①全酸蚀树脂水门汀应结合粘结剂同时使用。②牙本质涂布粘结剂后不单独固化可显著提高全酸蚀树脂水门汀与牙本质的粘结强度。     

模拟髓室压力对中层牙本质树脂微拉伸粘结强度的影响

目的评价髓室压力对中层牙本质树脂粘结强度的影响。方法32颗第三磨牙随机分组,实验组以15cm水柱模拟髓室压力。Clearfil S~3 Bond粘结剂作树脂光固化后微拉伸力学测试。结果实验组粘结剂应用时间为300 s时,微拉伸粘结强度明显下降。实验组和对照组相比较,150 s组和300 s组的微拉伸粘结强度差异均有统计学意义。结论模拟髓室压力会影响中层牙本质树脂微拉伸粘结强度。     

粘结剂类型对核树脂与牙本质的微拉伸粘结强度的影响

目的测试不同的粘结剂类型对核树脂与牙本质的粘结强度的影响,为临床选择合适的粘结剂和核树脂提供参考。方法选择20颗因阻生拔除的健康第三磨牙,磨除牙合面釉质,形成牙本质平面。随机分成ABCD四组,每组5颗牙齿。A组、B组所有牙本质粘结面涂布自酸蚀Contax粘结剂。C组和D组牙本质粘结面酸蚀剂处理后涂布SingleBond粘结剂,A组和C组用Luxa-Core核树脂,B组和D组用3MFiltekTMZ350纳米树脂进行分层固化粘结,切成约0.9mm×0.9mm的柱状试件,每组共30个试件。用微拉伸测试仪检测其粘接强度,用扫描电镜观察样本粘接界面的超微形态。结果 A组（36.03±9.25）MPa和B组（23.38±9.78）MPa与C组（14.27±8.63）MPa相比,差异有统计学意义（P〈0.05）,D组（38.80±10.56）MPa与B组、C组相比,差异有统计学意义（P〈0.05）,A组和D组相比,差异无统计学意义（P〉0.05）。两种核树脂的粘结界面均可见牙本质小管有树脂突形成,SingleBond酸蚀组树脂突比Contax自酸蚀组分布密度较密,长度较长。结论不同的粘结剂类型对核材料与牙本质的粘结强度有影响,要选择核树脂配套的粘结剂。     

自酸蚀粘结剂的预固化及其对复合树脂与牙本质和牙釉质粘结强度的影响

目的：评价并比较在填入复合树脂前对粘结剂进行光固化和粘结剂与复合树脂同步固化两种情况下．3种自酸蚀粘结剂与牙釉质和牙本质的剪切粘结强度。材料和方法：对120颗拔除的牙齿进行湿磨以在牙釉质和牙本质上形成粘结平面。按照厂家操作说明分别将3种粘结剂（Adper Prompt—L-Pop．Clearfil SE Bond和Xenolll）涂于牙釉质或牙本质上。半数样本涂布粘结剂后＆口刻光固化（PRC组）,另一半将复合树脂填入后再行光固化（COC组）。将复合树脂置入特氟龙管内并在其上方进行光固化。样本于室温储于去离子水中24h后．使用拉伸强度试验机进行剪切力加载直到断裂。用2因素方差分析、预固化和材料的单因素分析、以及Tukey显著性检验多重比较程序来分析剪切粘结强度（MPa）。所有检验均在5％显著性水平（n=10）进行。结果：与同步固化方法比较,先光固化粘结剂的方法显示其与牙本质的粘结强度明显增高（P〈0001）：而与牙釉质的粘结强度．PRC组与COC组并无显著差异（P=0．420）。结论：在固化复合树脂之前．对自酸蚀粘结剂预固化可产生更大的牙本质粘结强度：不同的自酸蚀粘结剂固化技术对釉质的粘结强度并无明显影响。     

牙本质表面状态对丙酮基粘结剂强度和界面的影响

目的：研究干燥或湿润的牙本质表面状态对丙酮基粘结剂粘结强度和粘结界面微观结构的影响，并探讨粘结强度和粘结界面微观结构之间的内在联系。方法：选用3种含有丙酮的湿粘结系统Gluma One-Bond、Bond-1和One-Step，将Chrisma树脂分别粘结在干燥或湿润的人牙本质表面，测试各组试件的微拉伸强度，并用扫描电镜观察和比较各组试件粘结界面超微结构的异同。结果：湿粘结时，粘结剂对牙本质表面的渗透较为充分，混合层均匀，厚度约为5μm，并可观察到牙本质小管和侧支小管中有明显的树脂突形成；干燥粘结时，形成的混合层变薄，并有不完全渗透的混杂层形成。干燥粘结时，3种粘结系统的微拉伸强度均有显著降低，下降幅度最高为39％，微拉伸破坏的方式主要是粘结界面的破坏。结论：含有丙酮的粘结系统在干燥粘结时，对牙本质表面的渗透性下降，微拉伸强度明显降低；微拉伸强度的测试，可以更客观地反映粘结强度的大小。     

纳米金刚石改性核树脂与牙本质的微拉伸粘结强度的研究

目的 检测纳米金刚石填料改性的自行合成的核树脂与牙本质的微拉伸粘结强度.方法 选择10颗因阻生拔除的健康第三磨牙,磨除牙合面釉质,形成牙本质平面.随机分成2组,每组5颗牙齿.采用自行合成的纳米金刚石填料改性的核树脂(UFD-C)和Luxa-Core(L-C)商品核树脂充填并分别粘结于牙本质面上,形成4mm～5mm高的树脂层.将牙齿及上方的粘结树脂样本平行于牙长轴片切成约0.9mm×0.9mm的柱状试件,每组共30个试件.用微拉伸测试仪检测其粘结强度,体视显微镜观察其断裂类型,用扫描电镜观察样本粘结界面和断面的超微形态.结果 UFD-C组与牙本质的微拉伸粘结强度均值为:(36.03±9.25)MPa,L-C组与牙本质的微拉伸粘结强度均值为:(36.80±10.56)MPa,两组的粘结强度差异无显著性.UFD-C组70%为粘结面断裂,L-C组80%为粘结面断裂.扫描电镜显示两种核树脂的粘结界面均有树脂突形成.结论 自行合成的纳米金刚石改性核树脂(UFD-C)与Luxa-Core核树脂(L-C)的微拉伸粘结强度差异无显著性,能达到牙体缺损粘结修复的要求.     

四种双固化树脂粘结剂与根管牙本质间微渗漏的研究

目的评价冷热循环对4种双固化树脂粘结剂与根管牙本质间微渗漏的影响。方法20颗健康上前牙随机分为4组。根管预备后选用4种粘结树脂及其配套粘结剂（Clearfil DC Core Automix,Calibra esthetic resincement,DMG LUXACORE Smartmix Dual,3M ESPE RelyX^TM Unicem）分别粘结直径1．2mm树脂纤维桩,并用此4种材料分别做树脂核。将试件冷热循环处理10000次（温度设定为4℃／60℃,浸泡时间30s,传递时间20s）后,用0．5％碱性品红溶液染色24h。将试件连续纵向剖开为四部分,体视显微镜下观察各剖面的微渗漏情况,并用Kmskal-WaillisH非参数检验进行统计分析。结果各种树脂粘结剂均存在微渗漏现象,各种粘结剂之间的微漏程度有显著性差异（P〈0．05）。结论冷热循环后4种双固化树脂粘结剂粘结纤维桩与根管牙本质之间均存在微渗漏现象,使用Clearfd DC Core Automix作为粘结树脂的试件微渗漏程度最轻。     

简化乙醇湿粘结对龋影响牙本质粘结强度的影响

目的:评估简化乙醇湿粘结技术对龋影响牙本质粘结强度的影响。方法:选取人慢性龋离体第三磨牙36颗去龋备洞后保留龋影响牙本质。随机分为6组,分别使用自制疏水性粘结剂,Prime & Bond NT(PB),Adper Single bond plus(SB)进行粘结,堆砌树脂厚度约4~5 mm。实验组采用简化乙醇湿粘结法,对照组采用传统水湿粘结法。制作1 mm ×1 mm ×8 mm的条形微拉伸强度试件,每组选取8个。采用万能材料试验机测试微拉伸强度并记录,观察断裂界面。结果:在自制疏水性粘结剂组中,实验组粘结强度较对照组有显著提高(P<0.05)。结论:简化乙醇湿粘结技术可以提高CAD界面的粘结强度,尤其是在与疏水性粘结剂联合运用时,有显著提高。     

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目的比较老年牙本质和青年牙本质与复合树脂间粘接强度的差异,评价Er,Cr：YSGG激光对牙本质与复合树脂间粘接强度的影响。方法于2012年2—3月在中国医科大学口腔医学院收集老年人（A组）和青年人（B组）离体牙标本各10颗,每组随机分为2个亚组,即A1、A2组和B1、B2组。A1、B1组采用Er,Cr：YSGG激光预备,A2、B2组采用传统涡轮手机预备,自酸蚀粘接剂结合Z350复合树脂充填,37℃水浴24h后,制备成沙漏状试件并进行微拉伸粘接强度测试。体式显微镜下观察并记录断裂模式。结果微拉伸粘接强度测试结果,青年牙本质组明显高于老年牙本质组,差异有统计学意义（P〈0．05）;激光预备组略高于手机预备组,差异无统计学意义（P〉0．05）。各组断裂模式多为界面断裂,组间差异无统计学意义（P〉0．05）。结论老年牙本质由于增龄性变化导致粘接强度降低;Er,Cr：YSGG激光预备对牙本质与复合树脂间粘接强度无不利影响,可作为传统涡轮手机的替代方法。     

The effect of different light-curing methods on temperature changes of dual polymerizing agents cemented to human dentin

AIM: This in vitro study aims to measure the temperature changes of resin luting cements cemented to human dentin when using different light curing systems for photo-activation. METHODS AND MATERIALS: The three different types of light-curing units (LCUs) used for photoactivation were quartz-tungsten halogen (QTH), light emitting diode (LED), and plasma arc (PAC). Two types of dual cure resin cements were used [Variolink II (VL) and Choice (CH)]. Feltik Z250 composite resin material was used to prepare composite discs. Thirty human dentin specimens were prepared for each resin luting cement (ten for each light source). A total of 60 specimens were fabricated. Resin cement was applied on a dentin bridge and covered with the prepared composite disc where specimens were fabricated. Temperature change was recorded with a digital thermometer. RESULTS: The lowest temperature was recorded when VL and CH were photo-activated with the PAC unit. The PAC unit produced significantly lower recorded temperatures than the LED and QTH units. No significant difference appeared between QTH and LED units in terms of recorded temperature. CONCLUSION: The PAC unit produced significantly lower temperature changes compared to QTH and LED curing units. The risk for temperature rise should be taken into consideration during photo-polymerization of adhesive resins with LED or QTH in deep cavities when dentin thickness is 0.5 mm.     

The effect of light-curing source and mode on microtensile bond strength to bovine dentin

PURPOSE: The purpose of this study was to evaluate the effects of different light-curing techniques on the microtensile bond strength of hybrid and packable resin composite to dentin. The null hypotheses were that different light-curing techniques do not affect the adhesion of resin composites to tooth structure and that different resin composites do not have a similar bond to dentin. MATERIALS AND METHODS: One hundred four box-shaped buccal preparations were made and dentin/enamel adhesive was applied according to the manufacturer's instructions (Single Bond 3M ESPE). A hybrid resin composite (Filtek Z250, A2, 3M ESPE) or a packable resin composite (Solitaire 2, A2, Heraeus Kulzer) were inserted in bulk and polymerized using one of these techniques (n = 13): (a) Soft-start (SS) using a halogen lamp (QTH); (b) LED low intensity; (c) Plasma arc (PAC) curing for 6 s for packable resin composite and 3 s for the hybrid resin composite; (d) Conventional (C) QTH curing for 40 s. Afterwards, specimens were thermocycled 1,000 times between 5 degrees C and 55 degrees C in tap water, and were sectioned into beams with a rectangular cross-sectional area of approximately 1 mm2. Microtensile bond strength testing was performed using a universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: Bond strength means +/- (SD) in MPa were: Filtek Z250: SSQTH = 17.9 (5.4); LED = 17.9 (6.4); PAC = 16.8 (6.8); CQTH = 16.1 (4.6). Solitaire 2: SSQTH = 12.4 (6.4); LED = 15.5 (4.3); PAC = 16.2 (4.4); CQTH = 13.8 (5.7). The data were structured in a split-plot design and analyzed by a two-way ANOVA and Tukey's tests (alpha = 0.05). CONCLUSION: The light-curing method did not significantly affect bond strengths. However, the bond strengths of the packable resin composite were significantly lower than those of the hybrid resin composite for all polymerization techniques, suggesting that the restorative material itself might be a more critical factor in adhesion than the curing method.     

Temperature rise during adhesive and resin composite polymerization with various light curing sources

This study evaluated the temperature rise in two different adhesive (Clearfil SE Bond [CSEB] and EBS-Multi [EBSM]) and composite systems (Clearfil AP-X [CAPX,] Pertac II [PII]) by the same manufacturer when illuminated by four different light sources: Light-emitting diode (LED), Plasma arc curing (PAC), high intensity quartz tungsten halogen (HQTH) and quartz tungsten halogen (QTH). Forty dentin disks were prepared from extracted premolars. These dentin disks were placed in apparatus developed to measure temperature rise. Temperature rise during photopolymerization of adhesive resin and resin composite was then measured. The mean values of temperature increases for adhesive and resin composites did not differ significantly (p=0.769). The highest temperature rise was observed during photopolymerization of EBSM with PAC (5.16 degrees C) and HQTH (4.28 degrees C), respectively. Temperature rise values produced by QTH (1.27 degrees C - 2.83 degrees C for adhesive resin; 1.86 degrees C - 2.85 degrees C for resin composite) for both adhesive and resin composites were significantly lower than those induced by PAC and HQTH (p<0.05). However, these values were significantly higher than those produced by LED (1.16 degrees C - 2.08 degrees C for adhesive resin; 1.13 degrees C - 2.59 degrees C for resin composite). Light sources with high energy output (PAC and HQTH) caused significantly higher temperature rise than sources with low energy output (QTH and LED). However, in this study, no temperature rises beneath 1-mm dentin disk exceed the critical 5.6 degrees C value for pulpal health.     

Analysis of the microtensile bond strength to enamel of two adhesive systems polymerized by halogen light or LED

With the development of composite resin polymerization techniques, LEDs were introduced to the market place. Based on the studied literature, the aim of this study was to evaluate, through microtensile testing, the bond strength to enamel of a composite resin associated to a conventional (multi-bottle) adhesive system or to a self etching primer adhesive system, polymerized by halogen light or LED (light emitting diode). Bovine teeth were divided into 4 groups with 10 teeth each (n = 10). Then the adhesives Scotchbond Multipurpose Plus (3M-ESPE) and Clearfil SE Bond (Kuraray) were applied following the manufacturers instructions. Both systems were polymerized for 10 s by halogen light (Degulux Soft Start-Degussa Hulls) set at 550 mW/cm(2) or by LED (Kerr Demetron) set at 600 mW/cm(2). The composite resin Filtek Z-250 was applied in four 1 mm increments with the aid of a square, condensation silicon, 5 mm x 5 mm matrix, and polymerized by either of light sources for 40 s. Scotchbond Multipurpose Plus polymerized by halogen light presented the highest bond strength values (39.69 +/- 7.07 MPa), and the other groups did not present statistically significant differences: Scotchbond Multipurpose Plus polymerized by LED (22.28 +/- 2.63 MPa), Clearfil SE Bond polymerized by halogen light (27.82 +/- 2.65 MPa) and by LED (22.89 +/- 5.09 MPa).     

Degree of conversion of adhesive systems light-cured by LED and halogen light

This study evaluated the effect of blue light emitting diode (LED) and quartz tungsten halogen (QTH) on the degree of conversion (DC) of an etch-and-rinse Single Bond adhesive system (SB) and a mixture composed of primer solution and resin bond from Clearfil SE Bond self-etching adhesive system (CB) using Fourier transform infrared analysis (FTIR). Adhesives were applied to potassium bromide pellet surfaces and FTIR analyses were performed before and after photo-activation for 10 s with either LED (Freelight 1 - 400 mw/cm(2)) or QTH (XL 3000 - 630 mw/cm(2)) light-curing units (n=8). Additional FTIR spectra were obtained from photo-activated samples stored in distilled water for 1 week. The DC was calculated by comparing the spectra obtained from adhesive resins before and after photo-activation. The results were analyzed by two-way split-plot ANOVA and Tukey's test (p<0.05). Both adhesive systems exhibited low DC (%) immediately after photo-activation (SB/QTH: 18.7 +/- 3.9; SB/LED: 13.5 +/- 3.3; CF/QTH: 13.6 +/- 1.9; CF/LED: 6.1 +/- 1.0). The DC of samples light-cured with LED was lower than DC of those light-cured with QTH, immediately after light curing and after 1 week (SB/QTH: 51.3 +/- 6.6; SB/LED: 50.3 +/- 4.8; CF/QTH: 56.5 +/- 2.9; CF/LED: 49.2 +/- 4.9). The LED curing unit used to photo-activate the adhesive resins promoted lower DC than the QTH curing unit both immediately after light curing and 1 week after storage in water.     

Color stability of composites subjected to accelerated aging after curing using either a halogen or a light emitting diode source

The purpose of this study was to evaluate, in vitro, the color stability of three composite resins of two different shades (A3 and C3) cured with either a quartz tungsten halogen (QTH) or a light emitting diode (LED) source. Forty specimens (20 x 2 mm) were prepared for each composite (Tetric Ceram(R), Heliomolar(R) and Esthet-X(R)), being 20 for each shade. In each group, 10 specimens were light-cured using the QTH unit and 10 with the LED source. The shade of the materials was evaluated before and after submitting the specimens to artificial accelerated aging (4 h UV-B/4 h condensing vapor), using a reflection spectrophotometer. deltaE means were calculated and analyzed statistically by 2-way ANOVA and Tukey's test at 5% significance level. Both A3 and C3 shades of Esthet-X composite resin showed the lowest color change when cured with the QTH light, while Tetric C3 cured with the QTH light showed the highest color change.     

Depth of cure and surface microhardness of composite resin cured with blue LED curing lights.

OBJECTIVES: This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available light emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). METHODS: The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. RESULTS: HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH lights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. SIGNIFICANCE: Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing.     

固化光源对正畸托槽光敏粘结剂抗剪切强度及粘结剂残留指数影响的研究

目的：研究普通卤素灯（QTH）和发光二级管灯（LED）对正畸托槽复合树脂光敏粘结剂（3M）和树脂加强型玻璃离子光敏粘结剂（GC）抗剪切力的影响,为临床正畸粘结材料和固化光源的选择提供一定依据。方法：选取新鲜拔除的第一双尖牙48颗,随机分为4组,使用不同粘结材料和不同光源配合粘结标准网底方丝弓托槽,采用微机万能材料实验机对托槽的粘结强度进行检测,同时记录粘结剂残留指数（ARI）。结果：3M抗剪切力及ARI值均显著大于GC（P〈0．05）;QTH和LED对3M和GC的抗剪切力及ARI值影响差别无统计学意义。结论：2种正畸光敏粘结剂抗剪切强度均符合临床要求,托槽去除后GC对牙面破坏较小;LED灯照可以节约一半光照时间并能达到普通卤素灯的光照效果,正畸托槽粘结建议使用LED灯作为固化光源。