不同表面处理的纤维桩微拉伸粘接强度研究

目的:通过微拉伸粘接强度测试法测试在纤维桩表面经过6种不同的处理后与核树脂的粘接强度,探索何种表面处理方法能显著提高纤维桩与核树脂的粘接强度,为临床应用提供参考。方法:将30根石英纤维桩随机分成6组,每组5根。A组纤维桩表面涂布粘接剂,B组涂布硅烷处理剂,吹干后涂粘接剂,C组5%氢氟酸酸蚀30sec,流水冲洗吹干后处理同A组,D组5%氢氟酸酸蚀30sec,流水冲洗吹干后处理同B组,E组24%双氧水处理,后操作同A组,F组24%双氧水处理后操作同B组。在桩周分层固化核树脂,用低速锯沿纤维桩外周平行片切,再垂直粘接面片切成横截面约0.9mm×0.9mm的长方柱状试件,每组15个,用微拉伸粘接强度测试法测试纤维桩与核树脂的微拉伸粘接强度,体视显微镜观察断裂类型。结果:A组微拉伸粘接强度8.78±2.20MPa,B组9.35±1.92MPa,C组15.50±2.87MPa,D组22.98±3.24MPa,E组16.64±2.70MPa,F组24.88±3.9 0MPa。用氢氟酸酸蚀的C组和D组和用双氧水处理的E组和F组的微拉伸粘接强度明显高于A组B组(P<0.05)。用氢氟酸酸蚀后再硅烷化处理的D组比C组、用双氧水处...     

三种粘接剂粘接不同牙本质的微拉伸粘接强度比较

目的采用微拉伸粘接强度实验测定3种牙本质粘接剂粘接楔状缺损处硬化牙本质的粘接强度。方法选择有典型楔状缺损并因牙周病拔除的上颌前磨牙30颗作为实验组，正常上颌前磨牙30颗作为对照组，使用粘接剂A（全酸蚀粘接剂Scotchbond Multi—Purpose）、B（一步法自酸蚀粘接剂Adper Prompt L-Pop）和C（两步法自酸蚀粘接剂Contax）处理硬化牙本质和正常牙本质表面，相应树脂修复。测试两组试件的微拉伸粘接强度。结果粘接剂A、B、C粘接硬化牙本质的微拉伸粘接强度分别为46．805MPa、39．045MPa、29．852MPa。粘接剂A和C与硬化牙本质的微拉伸粘接强度低于正常牙本质，而粘接剂B与之相反，差异有统计学意义（P〈0．05）。结论牙颈部楔状缺损处硬化牙本质由于结构上的特殊性可造成粘接困难。酸性强有利于粘接剂与硬化牙本质的粘接。     

丹酚酸B对人牙本质自酸蚀粘结强度的影响

目的：探讨丹酚酸B对牙本质自酸蚀粘结即刻及长期粘结强度的影响。方法：将10颗新鲜拔除的人下颌第三磨牙去除面牙釉质,暴露中层牙本质,打磨后制备出标准粘结面,以硬组织切片机将每颗牙均分为近中及远中两部分,自凝塑料包埋牙根,随机选取每颗实验牙的近中或远中部分共10个牙体单位于牙本质粘结面涂布两层Adper Prompt自酸蚀粘结剂（3MESPE）,光固化10s后以Filtek Z350通用型纳米树脂（3MESPE）堆塑5mm高的树脂核;其余10个牙体单位则先以丹酚酸B处理牙本质粘结面,再以相同方法与材料制作树脂核。以硬组织切片机将各牙体单位切为1mm×1mm×8mm的微拉伸试件,每个牙体单位选出2个试件并随机分组,最终形成A1、A2、B1、B2四组（n=10）,A1设为对照组。对A1、B1组试件进行即刻微拉伸强度测试,A2、B2组试件水储6个月后进行微拉伸强度测试,评估其粘结强度。实验所得结果采用SPSS18.0软件进行ANOVA两因素方差分析和LSD多重检验。结果：丹酚酸B处理与未处理组的即刻微拉伸强度分别为（40.05±2.24）MPa、（41.58±1.98）MPa,两组即刻粘结强度无统计学差异;6个月水储后丹酚酸B处理组微拉伸强度为（18.96±2.05）MPa,高于未处理组（13.14±2.17）MPa（P〈0.05）。结论：丹酚酸B对牙本质自酸蚀粘结的即刻粘结强度没有明显影响,但能有效减缓长期（6个月）粘结强度的降。     

浓硫酸酸蚀聚醚酮酮的时间对其与牙本质剪切粘接强度的影响

目的研究浓硫酸酸蚀聚醚酮酮(polyether?ketone?ketone,PEKK)不同时间对其与牙本质剪切粘接强度的影响,为临床使用PEKK修复体的粘接操作提供科学依据。方法制备PEKK试件44个,随机平均分为A、B、C、D 4组:A组为对照组,仅用水磨砂纸打磨;B组、C组、D组为实验组,分别用98%浓硫酸酸蚀经打磨试件表面5 s、30 s、60 s。另外,每组随机抽取1个试件用慢速切割机制备出剖面,在扫描电镜下观察其剖面的表面形貌。4组试件与牙本质通过树脂粘接后在37℃蒸馏水浸泡24 h,测量剪切粘接强度后统计分析,通过扫描电子显微镜与体视显微镜检查试件断裂界面,统计粘接失败类型。结果B组PEKK试件酸蚀处理后剖面呈海绵状且孔隙大小均匀,C组、D组可见试件剖面有破坏状孔蚀样结构;剪切粘接强度B组(16.84±1.84)MPa、C组(12.33±1.22)MPa和D组(6.44±1.18)MPa均大于A组(3.99±1.06)MPa(P<0.05),其中B组与牙本质的剪切粘接强度最高(16.84±1.84)MPa。结论采用98%浓硫酸酸蚀PEKK表面5 s处理方法可以使PEKK与牙本质获得较好的剪切粘接强度。     

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。     

EDTA预处理硬化牙本质对树脂粘结强度的影响

目的：采用微拉伸试验比较EDTA（Ethylene Diamine Tetraacetie Acid,乙二胺四乙酸）预处理硬化牙本质前后的离体牙树脂粘结强度。方法：选择24颗具有典型楔状缺损的离体牙,12颗离体牙的楔状缺损处为Ⅲ级以上硬化牙本质,其余12颗为正常牙本质。以平分楔状缺损为标准对离体牙进行纵剖,随机分为硬化牙本质对照组A与实验组B;正常牙本质对照组C与实验组D。实验组均使用EDTA（Glyde File Prep EDTA）预处理牙本质表面,再行自酸蚀树脂粘结。测定4组样本的微拉伸粘结强度。结果：微拉伸实验显示测得A、B、C、D,4组样本的微拉伸强度分别为（9.49±2.23）MPa、（10.50±2.16）MPa、（10.89±4.76）MPa、（10.99±5.21）MPa。实验组B的粘结强度显著高于对照组A,有统计学意义（P〈0.05）;而实验组D的粘结强度略高于对照组C,但无统计学意义。结论：利用EDTA预处理能提高硬化牙本质的自酸蚀树脂粘结强度,但对正常牙本质无明显作用。     

缩短酸蚀时间对乳牙及年轻恒牙粘结强度的影响

目的研究缩短酸蚀时间对乳牙及年轻恒牙粘结强度的影响,为临床上掌握更恰当的酸蚀时间提供一定的理论指导。方法选取新鲜拔除无龋坏乳磨牙20颗,无龋坏年轻恒牙20颗,磨除牙牙合面牙釉质,形成牙本质平面。乳牙随机分为A、B、C、D组,年轻恒牙随机分为E、F、G、H组,A、B组和E、F组牙本质应用Single Bond 2(SB2)全酸蚀粘结系统,A、E组酸蚀15 s;B、F组酸蚀7 s;C、D组和G、H组应用Kerr Optibond Versa(OV)自酸蚀粘结系统,C、G组用前处理剂涂布20 s;D、H组用前处理剂涂布10 s。树脂分层固化,恢复牙冠。用低速锯将牙齿片切成横截面积约为1.0 mm×1.0 mm的长方体状样本,进行微拉伸强度(micro TBS)的测试。结果微拉伸强度分别为A组(14.95±3.79)MPa,B组(16.74±2.77)MPa,C组(20.80±3.97)MPa,D组(20.50±3.98)MPa,E组(20.95±2.68)MPa,F组(17.26±3.32)MPa,G组(25.70±2.95)MPa,H组(20.98±3.13)MPa,A组与B组、C组与D组无统计学差异;F组A组,D组>B组,G组>E组,H组>F组,差异有统计学意义(P<0.05)。结论缩短酸蚀时间,乳牙的粘结强度没有明显变化,年轻恒牙的粘结强度明显降低;应用OV自酸蚀粘结系统的粘结强度高于应用SB2全酸蚀粘结系统的粘结强度。     

不同表面处理对聚乳酸可吸收桩与树脂核间粘结性能的影响

目的:探讨不同表面处理方法对聚乳酸桩与树脂核粘结性能的影响。方法:将25根聚乳酸桩随机分为A、B、C、D、E 5组(n=5),A组表面仅涂布粘结剂;B组表面涂布氯仿后再涂布粘结剂;C组表面涂布氯仿与粘结剂按1∶1混合5 s后的混合物;D组表面涂布氯仿与粘结剂按1∶2混合5 s的混合物;E组表面涂布氯仿与粘结剂按2∶1混合5 s的混合物;另取5根玻璃纤维桩作为F组(对照组),表面涂布粘结剂。处理后的各组桩分别与Filtek Z350树脂核粘结制成棒状试件后进行微拉伸测试;体视显微镜观察各样本的断裂类型,SEM观察桩-树脂核断裂界面;并对数据进行统计分析。结果:C组微拉伸强度最高(20.58±3.35)MPa,与其他各组相比P<0.05;随后依次为E组(13.35±3.21)MPa、D组(12.80±2.77)MPa、F组(12.24±1.40)MPa、B组(10.91±1.61)MPa、A组(5.03±1.48)MPa,两两相比,B组与E组比较,P<0.05,D、E、F组间比较P>0.05,其余各组间差异P<0.05;各组断裂模式两两相比P<0.05,C组以树脂内聚破坏为主。结论:将氯仿和粘结剂按1∶1的比例混合后处理聚乳酸桩表面可提高聚乳酸桩-树脂核的粘结强度。     

过硼酸钠内漂白对牙本质与树脂粘接强度影响的实验研究

目的比较牙本质经过硼酸钠漂白后在不同时间粘接树脂,其抗剪强度变化及粘接界面的超微形态。方法18颗恒前磨牙随机分为3组。A组为对照组：人工唾液内3周后制备牙本质粘接面,粘接树脂。B组：牙齿漂白3周后制备牙本质粘接面,粘接树脂;C组：牙齿漂白3周,人工唾液内储存2周后制备牙本质粘接面,粘接树脂。电子万能材料实验机测试抗剪粘接强度;扫描电镜观察粘接界面超微形态。结果①抗剪强度测试结果：A组：18.61±3.56MPa;B组：12.10±2.64MPa;C组：16.78±2.84MPa。②统计学分析：单因素方差分析表明三组样本均数之间存在统计学差异（P〈0.05）。各样本均数的两两比较（SNK-q法）结果显示A与B组,B与C组的抗剪强度值差别有统计学意义（P〈0.05）,而A与C组的抗剪强度值之间无统计学差异（P〉0.05）。③粘接界面的SEM观察结果：A组粘接界面上可见大量的树脂突渗入牙本质小管内,树脂突的长度较长并且均匀。B组粘接界面上的树脂突稀少,长度较短并且长短不一。C组粘接界面可见有较多的树脂突,长度均匀但较为短小。结论过硼酸钠漂白后牙本质的粘接时间对牙本质与树脂的粘接强度有影响：牙齿漂白后即刻粘接树脂,会降低牙本质与树脂的粘接强度,而漂白后延迟2周再粘接树脂能够恢复牙本质与树脂的粘接强度。     

不同根管内壁处理方法对玻璃离子水门汀与根管牙本质粘接强度的影响

目的：评价不同根管内壁处理方法对树脂改性玻璃离子水门扪‘与根管牙本质粘接强度的影响。方法：新鲜拔除的42个完整前牙或单根管前磨牙，于釉一牙骨质界处水平截断，根据不同处理根管壁＋粘接纤维桩的方法随机分为7组：A组：无酸蚀＋GC Fuji I；B组：酸蚀＋GC Fuji I；C组：酸蚀＋singlebond2＋GCFujiI；D组：无酸蚀＋GCFuji ⅡLC；E组：酸蚀＋GC VujiⅡLC；F组：酸蚀＋singlebond2＋GCVujiⅡLC：G组：酸蚀＋singlebond2＋ClearfilDCCoreAutomix。粘结处理后垂直牙根长轴切割成1mm厚薄片，在万能测试机上进行微推出测试。结果：7组粘接强度分别为A组（1．6367±0．2673）MPa；B组（1．9933±0．1906）MPa；C组（2．4800±0．5349）MPa；D组（3．1967±0．7068）MPa：E组（3．9385±0．2782）MPa；F组（5．5317±0．5545）MPa；G组（8．2510±0．7757）MPa。D组、E组、F组均相应高于相同根管内壁处理方法的A组、B组、C组（p〈0．05），但均低于G组如〈O．05）；F组〉E组〉D组（P（0．05），ABC三组间无显著差异（p〉O．05）。结论：不同方法处理根管内壁对粘接材料与根管牙本质间的粘接强度有影响。     

Bond strengths of three different dentin adhesive systems to sclerotic dentin

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p < 0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p > 0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.     

Tubular occlusion prevents water-treeing and through-and-through fluid movement in a single-bottle, one-step self-etch adhesive model

Water entrapment occurs at resin-dentin interfaces of one-step self-etch adhesives. We hypothesized that by preventing water fluxes from dentin, any water entrapment would be attributed to incomplete removal of adhesive solvents. We tested this hypothesis by bonding to transparent carious dentin containing occluded dentinal tubules. An experimental single-bottle, one-step self-etch adhesive was applied to flat surfaces of caries-affected dentin surrounded by sound dentin, with or without pulpal pressure. Resin-dentin interfaces were examined with TEM after silver-impregnation. Although caries-affected dentin was highly porous, adhesive layers were devoid of silver deposits when tubules were occluded. Conversely, variable extents of water-treeing and water-droplets were identified from adhesive layers in bonded sound dentin. Water-treeing and water-droplet formation, being manifestations of evaporative and convective water fluxes, can be eliminated during bonding to occluded transparent carious dentin. However, the highly porous nature of this clinically relevant substrate after bonding may lead to potentially undesirable consequences.     

In vitro interfacial relationship between human dentin and one-bottle dental adhesives.

OBJECTIVES: One-bottle dentin adhesives combine primer and adhesive resin into a single solution. This study was conducted to determine the bond strengths to dentin of four one-bottle bonding systems and to evaluate their SEM interfacial morphology. The hypothesis to be tested was that the water-based bonding system would produce lower bond strengths and less complete penetration into dentin than other bonding systems that are dissolved in organic solvents. METHODS: Forty extracted molars were ground to expose middle dentin and were randomly assigned to four groups (n = 10): Group 1--Experimental Single Bond (3M Dental Products Division); Group 2--Prime&Bond 2.1, pre-launch version (Dentsply DeTrey); Group 3--Syntac Single-Component (Vivadent); Group 4--Tenure Quik with Fluoride (Den-Mat Co.) The surfaces were treated according to manufacturers' instructions. After 24 h in water, the specimens were thermocycled, and the bond strengths were measured in shear. The data were analyzed with ANOVA and Duncan's test at a confidence level of 95%. Further, the adhesives were also applied to 600 microns thick dentin disks. After preparing polished cross sections, the bonded interfaces were demineralized, deproteinized, and observed under a FE-SEM. The morphological appearance of the resin-dentin interface surfaces was compared by screening the entire resin-dentin interface for each specimen. RESULTS: Two morphological characteristics were evaluated: 1) the depth of resin penetration into the tubules and 2) the thickness and density of the resin-dentin interdiffusion zone. Single Bond showed statistically higher mean shear bond strengths (p < 0.001) compared to the other three materials. Specimens prepared with Syntac Single-Component and Prime&Bond 2.1 were ranked in the intermediary Duncan's grouping. Specimens bonded with Tenure Quik with Fluoride exhibited the lowest mean shear bond strength. All materials penetrated and hybridized dentin. Single Bond formed a thick layer of adhesive resin on the top of the interdiffusion area without debonding, whereas some areas of debonding were observed on the top of the hybrid layers for Prime&Bond 2.1 and Syntac Single-Component. For the water-based adhesive Syntac Single-Component, the interdiffusion zone displayed a thick filigree pattern, containing scattered open spaces between the resin-enveloped collagen fibers. Tenure Quik with Fluoride did not thoroughly infiltrate the demineralized dentin zone, resulting in wide gaps in all specimens. Prime&Bond 2.1 formed the shortest resin tags, whereas Syntac Single-Component formed the longest resin tags. SIGNIFICANCE: Bonding to dentin remains unpredictable using one-bottle bonding systems. The chemistry of each individual material may be more important than the type of solvent.     

Effect of bur-cut dentin on bond strength using two all-in-one and one two-step adhesive systems

PURPOSE: To compare the microtensile bond strength (MTBS) of two all-in-one adhesive systems and one experimental two-step self-etching adhesive system to two types of bur-cut dentin. MATERIALS AND METHODS: Using one of the three adhesives, Xeno CF Bond (Xeno), Prompt L-Pop (PL), or the experimental two-step system ABF (ABF), resin composite was bonded to flat buccal and root dentin surfaces of eight extracted human premolars. These surfaces were produced using either regular-grit or superfine-grit diamond burs. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into six or seven slices approximately 0.7 mm thick perpendicular to the bonded surface. They were then subjected to microtensile testing. The surfaces of the fractured specimens were observed microscopically to determine the failure mode. In addition, to observe the effect of conditioning, the two types of bur-cut dentin surfaces were conditioned with the adhesives, rinsed with acetone, and observed with SEM. RESULTS: When Xeno and PL were bonded to dentin cut with a regular-grit diamond bur, MTBS values were lower than to superfine bur-cut dentin, and failures occurred adhesively at the interface, whereas the experimental two-step adhesive showed no significant difference in microtensile bond strength between two differently cut surfaces. CONCLUSION: The all-in-one adhesives tested here improved bond strengths when bonded to superfine bur-cut dentin as a substrate, whereas the experimental two-step adhesive system showed unchanged bonding to both regular and superfine bur-cut dentin surfaces.     

In vitro bracket bond strength to acid-etched or air-abraded enamel.

PURPOSE: This study evaluated, in vitro, the capacity of a dentin bonding agent to improve the bond strength of orthodontic brackets using air abrasion enamel preparation. METHODS: Each of the enamel surfaces received a different treatment prior to bonding procedures. Group 1 received acid-etched with 38% phosphoric acid for 30 seconds. Group 2 received acid-etched with 38% phosphoric acid for 30 seconds, dentin bonding agent (Scotchbond MultiPurpose) applied after rinse completed. Group 3 received abrasion-etched (particle size 50 microns, 120 psi). Group 4 received abrasion-etched, dentin bonding agent applied after etching completed. Unfilled adhesive resin (Ormco light cured sealant) was applied followed by a premolar bracket (Ormco meshed mini-twin) with adhesive (Ormco light cured adhesive) placed on the back. Shear bond strengths were measured using an INSTRON machine and the site of bond failure was determined under 3X magnification. RESULTS: The shear bond strength obtained with a traditional acid-etch, in vitro, was not improved significantly by the use of a dentin bonding agent. Air abraded surfaces showed very low bond strengths with all treatments. CONCLUSIONS: Tested in vitro, air-abraded surfaces provide clinically unacceptable bond strength when compared to acid-etched enamel surfaces.     

Influence of eugenol-containing temporary cement on bonding of self-etching adhesives to dentin

PURPOSE: To investigate the influence of eugenol-containing temporary cement on bonding of resin composite to dentin mediated by self-etching adhesives. MATERIALS AND METHODS: Flat dentin surfaces were produced by grinding of extracted human molars. The dentin surfaces were either used directly or after a one-week exposure to a zinc oxide-eugenol cement (IRM). A resin composite (Herculite XRV) was bonded to the dentin surfaces following treatment with 1 of 6 self-etching adhesives (AdheSE, Adper Prompt L-Pop, Clearfil SE Bond, iBond, OptiBond Solo Plus - Self-Etch Adhesive System, and Xeno III). An adhesive system containing 0.5 M EDTA as dentin conditioner (Gluma Classic) was included as negative control, and an etch-and-rinse adhesive system (OptiBond FL) was included as positive control. After storage in water at 37 degrees C for 1 week, the bonded specimens were fractured in shear (n = 8 in each group). RESULTS: Previous contact of dentin with zinc oxide-eugenol cement significantly decreased the bond strength mediated by the negative control and did not affect the bond strength mediated by the positive control. For the self-etching adhesives, no effect was found of previous contact with zinc oxide-eugenol cement. With and without previous contact with zinc oxide-eugenol cement, the etch-and-rinse adhesive system yielded a significantly higher bond strength than all other adhesive systems. CONCLUSION: Previous contact with zinc oxide-eugenol cement did not decrease the bond strength of resin composite to dentin mediated by self-etching adhesives. This finding suggests that eugenol-containing temporary cements may be safe to use in combination with self-etching adhesives.     

Water uptake of bonding systems applied on root dentin surfaces: a SEM and confocal microscopic study.

OBJECTIVES: Dentin adhesives have been proposed as desensitizing agents to seal exposed root dentin surfaces. Simplified 'one-step' dentin adhesives are highly permeable to water. The authors hypothesized that a lactic acid challenge may increase permeability of simplified adhesives and may induce fast degradation of bonding. This phenomenon adversely affects their durability as long term desensitizing agents. The aim of this in vitro study was to evaluate the ability of four dentin adhesives to seal root dentin surfaces that were exposed to water and lactic acid challenges. METHODS: Four commercially-available dentin adhesives were applied with a small sponge to the root dentin of extracted human molars as de-sensitizing agents. Impression replicas of the adhesive-covered root dentin were fabricated after water immersion, as a control, and after lactic acid challenge. The replicas were examined with SEM for quantitative comparison of fluid droplet formation on the surfaces. The bonded specimens were also examined using reflected light confocal microscopy. RESULTS: Replicas of water droplets were observed on the adhesive surfaces, by SEM which corresponded with direct confocal observation of blisters and voids from the surface of the bonded specimens. There were significantly more water droplets from samples that were subjected to lactic acid challenge than water only immersion. SIGNIFICANCE: Although the dentin adhesives examined were able to cover exposed root dentin, they all exhibited fluid transudation through the polymerized adhesives. Dentin adhesives were also susceptible to surface degradation after lactic acid challenge. As simplified self-etch adhesives were highly water permeable and exhibited the most extensive surface damage, they may not be the best adhesives to be used for long-term dentin desensitization. These preliminary in vitro findings warrant validation in vivo.     

Bonding of single-component adhesives to dentin following chemomechanical caries removal

PURPOSE: To determine the effect of chemomechanical caries removal on the bonding quality of contemporary single-component adhesives to dentin. MATERIALS AND METHODS: N-monochloro-DL-2-aminobutyrate solution (NMAB) and Carisolv gel were used to chemomechanically remove dentin caries in 60 extracted human molars. Caries removal with rotating instruments served as the control. Two single-component adhesive systems, Syntac Single Component and Excite, were applied to bond the hybrid composite Tetric Ceram to the treated dentin surfaces. The prepared samples were sectioned for microtensile bond strength testing and SEM examination of the bonding interfaces. The debonding patterns of the fractured samples were also assessed. RESULTS: No statistically significant differences were found between the bond strengths of either adhesive to the conventionally and the NMAB-treated dentin (p > 0.05). However, the Carisolv-treated dentin yielded significantly higher (p > 0.05) bond strength values with both adhesives compared to those on dentin prepared with rotating instruments. No statistical difference could be discerned between the 2 adhesive systems (p > 0.05), nor was the interaction between the 2 variables under investigation (method of caries removal and the type of adhesive) statistically significant (p = 0.7712). SEM images indicated unspecific effects of the tested variables on both the thickness of the hybrid layer and the length of the resin tags. CONCLUSION: Under the conditions of this study, using the Carisolv chemomechanical caries removal system to prepare dentin surfaces enhanced the dentin/adhesive bond strength. In addition, the chemical nature of the adhesive systems seems to have no effect on the values of bond strength.     

五种牙本质粘结系统微拉伸强度的比较

目的比较不同类型自酸蚀牙本质粘结系统的粘结强度,为临床应用提供参考。方法选择4种自酸蚀粘结系统Clearfil S3Bond,i Bond,Clearfil SE Bond,XenoⅢ,1种全酸蚀粘结系统Single Bond2,用微拉伸法测试这些粘结系统的粘结强度并进行比较。结果全酸蚀粘结剂Single Bond2的微拉伸强度最高,与自酸蚀粘结剂粘结强度有显著差异（P〈0.05）。自酸蚀粘结剂i Bond,S3Bond,XenoⅢ两两之间粘结强度无显著差异（P〉0.05）。SE Bond的粘结强度显著高于i Bond,S3Bond和XenoⅢ（P〈0.05）。结论第五代牙本质粘结剂具有较强的粘结强度,但第七代牙本质粘结剂临床操作更为方便。     

Influence of Er,Cr:YSGG laser treatment on the microtensile bond strength of adhesives to dentin

PURPOSE: In light of the concept of minimally invasive dentistry, erbium lasers have been considered as an alternative technique to the use of diamond burs for cavity preparation. The purpose of this study was to assess the bonding effectiveness of adhesives to Er,Cr:YSGG laser-irradiated dentin using irradiation settings specific for cavity preparation. MATERIALS AND METHODS: Fifty-four midcoronal dentin surfaces, obtained from sound human molars, were irradiated with an Er,Cr:YSGG laser or prepared with a diamond bur using a high-speed turbine. One etch-and-rinse (Optibond FL/Kerr) and three self-etching adhesives (Adper Prompt L-Pop/3M ESPE, Clearfil SE Bond/Kuraray, and Clearfil S3 Bond/Kuraray) were used to bond the composite to dentin. The microtensile bond strength (microTBS) was determined after 24 h of storage in water at 37 degrees C. The Kruskal-Wallis test was used to determine pairwise statistical differences (p < 0.05). Prepared dentin surfaces, adhesive interfaces, and failure patterns were analyzed using a stereomicroscope and Field-emission gun Scanning Electron Microscopy (Feg-SEM). RESULTS: Significantly lower microTBS was observed to laser-irradiated than to bur-cut dentin (p < 0.05), irrespective of the adhesive employed. Feg-SEM photomicrographs of lased dentin revealed an imbricate patterned substrate and the presence of microcracks at the dentin surface. CONCLUSION: Morphological alterations produced by Er,Cr:YSGG laser-irradiation adversely influence the bonding effectiveness of adhesives to dentin.