CPP-ACP/ACFP预处理的牙本质与树脂粘结剂粘结作用的研究

目的:通过设立对比实验,研究酪蛋白磷酸肽-无定形磷酸钙(Casein phosphopetide-amorphic calcium phosphat,CPP-ACP)及酪蛋白磷酸肽-无定形磷酸氟钙(Casein phosphoetide-amorphic calcium fluoride phosphate complexes,CPP-ACFP)对牙本质小管的封闭效果及对树脂粘结剂粘结强度的影响。方法:将36个试件随机分为自酸蚀和全酸蚀组,每组再分空白组、GC组、GC plus组3个亚组(n=6)。采用扫描电子显微镜(SEM)观察CPP-ACP和CPP-ACFP预处理牙本质1 d和7 d后的表面形貌改变;用能谱分析,计算钙磷比值,分析羟基磷灰石晶体结构和成份;每个试件上均堆积厚约4 mm的Z350树脂,通过万能测试机进行微拉伸强度测试,分析CPP-ACP和CPP-ACFP预处理对粘结剂粘结强度的影响;使用体视显微镜,观察界面的断裂模式,并对结果进行统计分析。结果:SEM显示,经预处理的牙本质小管直径减小,经多次预处理与1次相比,牙本质小管几乎完全封闭;能谱分析表明经预处理的牙本质与空白组牙本质Ca∶P比值变化并无统计学差异,新形成的羟基磷灰石结构和成份与牙本质类似;微拉伸实验结果显示,在牙本质表面应用CPP-ACP或CPP-ACFP后,可降低全酸蚀粘结剂single bond2的粘结强度(P＜0.05),而对自酸蚀粘结剂ibond的粘结强度无明显影响;两者对同一种粘结剂粘结强度的影响无统计学意义;体视显微镜观察,各组断裂模式均以粘结面断裂为主。结论:粘结前使用CPP-ACP或CPP-ACFP预处理牙本质表面,可以封闭牙本质小管,多次应用效果更加显著;CPP-ACP或CPP-ACFP预处理后对自酸蚀粘结剂粘结强度没有影响;会降低全酸蚀粘结剂的粘结强度。     

复合树脂联合两种酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度比较

目的:比较复合树脂联合全酸蚀和自酸蚀粘结剂与乳牙釉质及牙本质的剪切粘结强度。方法:收集新鲜拔除的滞留乳磨牙48个,随机分为4组,分别制备全酸蚀和自酸蚀粘结剂的釉质和牙本质试件,电子万能试验机测定各组剪切强度;体视显微镜下观察试件断面的破坏模式;扫描电镜观察粘结界面情况。结果:全酸蚀粘结剂组的釉质剪切强度明显高于牙本质剪切强度(P<0.05);自酸蚀粘结剂组釉质与牙本质剪切粘结强度无统计学差异(P>0.05);全酸蚀粘结剂组的釉质、牙本质剪切粘结强度均明显高于自酸蚀粘结剂组(P<0.05);体视显微镜及扫描电镜观察均显示,全酸蚀粘结剂与釉质和牙本质的粘结界面结合程度好于自酸蚀粘结剂。结论:全酸蚀粘结剂处理对乳牙釉质及牙本质的剪切粘结强度高于自酸蚀粘结剂。     

全酸蚀与自酸蚀粘结系统与正常牙本质粘结强度的比较

目的本研究选取了3种知名品牌的全酸蚀和自酸蚀粘结剂,比较其与正常牙本质的粘结强度及相同品牌树脂粘结剂与不同品牌树脂粘结剂的粘结强度。方法选择60颗新鲜拔除的人第三磨牙,去除牙合面釉质层,随机分为12组,选用3种品牌全酸蚀和自酸蚀粘结剂Excite、AdheSE;Prime&BondNT、XenoⅢ;Singlebond2、Adper Prompt,分别应用于暴露的表层牙本质上,再用树脂恢复牙冠。将牙齿片切成横截面积约为1mm2的长方体状样本,检测其粘结强度。结果结果显示Excite与AdheSE、Prime&Bond NT与XenoⅢ、Singlebond2与Adper Prompt之间的粘结强度无显著差异(P>0.05),Prime&Bond NT、Singlebond2与TPH树脂,XenoⅢ、Adper Prompt与TPH树脂粘结强度无显著差异(P>0.05);Prime&Bond NT、Singlebond2与Z-250树脂,XenoⅢ、Adper Prompt与Z-250树脂粘结强度无显著差异(P>0.05)。结论全酸蚀/自酸蚀粘结系统与正常牙本质间的粘结强度无显著差异;不同品牌间的粘结剂和树脂一起应用不影响其粘结强度。     

自酸蚀粘结剂牙本质粘结界面未封闭结构观察

目的观察并评价3种自酸蚀粘结剂(ClearfilTM SE Bond、AdperTM PromptTM、ONE-UP Bond F)牙本质粘结界面的未封闭结构。方法选取人体24颗无龋坏磨牙,用600目碳化硅砂纸在流水冲洗下预备出统一的牙本质粘结面玷污层。分别用3种自酸蚀粘结剂和1种全酸蚀粘结剂(对照组)按使用说明进行粘结处理。每颗牙齿标本垂直于粘结面切割出粘结试件,分别进行氨化硝酸银、三色法染色,观察牙本质粘结界面。结果在电镜和光学显微镜下均观察到3种自酸蚀粘结剂牙本质粘结界面混合层底部的纳米渗漏。结论自酸蚀粘结剂牙本质粘结界面中存在部分脱矿的未封闭牙本质结构。     

冷热循环对牙本质粘结耐久性的影响

目的:研究冷热循环对牙本质粘结强度和粘结界面纳米渗漏的影响.方法:选取30个无龋损人磨牙,用600目碳化硅砂纸在流水冲洗下预备牙本质粘结面,分别用3种(Prime&Bond NT,Adper Prompt和Contax)粘结剂进行粘结处理,复合树脂充填.纵向片切牙齿,制备粘结面积为1 mm2的条形树脂牙本质试样.冷热循...     

不同牙本质粘结系统处理后的牙釉质表面及粘结界面扫描电镜观察

目的观察不同牙本质粘结系统处理牙釉质后,牙釉质表面和粘结界面的超微结构特点。方法选取人离体下第三磨牙14颗,湿性打磨颊面牙釉质。随机选择6颗牙,分别使用全酸蚀牙本质粘结系统Adper^TM Single Bond2（SB2）、一步法自酸蚀牙本质粘结系统Cleaxfil S^3Bond（CS3）和iBond GI（IB）与光固化复合树脂粘结牙釉质。硬组织切片,扫描电镜观察各粘结系统与牙釉质粘结界面形态特点。另8颗牙,随机分4组,对照组不再做任何处理,另3组分别用SB2的酸蚀剂（35％磷酸）、CS3和IB处理牙釉质表面,扫描电镜观察牙釉质表面形态特点。结果SB2的酸蚀剂酸蚀牙釉质表面后,脱矿明显,形成典型的蜂窝状结构;SB2粘结剂在牙釉质粘结界面形成密集的树脂突,长约5μm;CS3和IB对牙釉质的脱矿较弱,与牙釉质粘结界面无明显的树脂突形成。结论自酸蚀粘结系统CS3和IB与牙釉质粘结界面的超微结构和全酸蚀粘结系统SB2相比较存在明显差异。     

人工唾液浸泡对牙本质黏结耐久性的影响

目的:研究人工唾液浸泡对牙本质黏结强度和黏结界面纳米渗漏的影响.方法:选取30个无龋损人磨牙,用600目碳化硅砂纸在流水冲洗下预备牙本质黏结面,分别用3种(Prime&Bond NT,Adper Prompt和Contax)黏结剂进行黏结处理,复合树脂充填.制备黏结面积为Imm2的条形树脂牙本质试件,在人工唾液中分别浸泡1天(对照组)、90天、180天,然后进行硝酸银染色后测定微拉伸黏结强度,场发射扫描电镜下比较界面纳米渗漏.结果:唾液浸泡180天后,Prime&Bond NT和Adper Prompt黏结强度显著小于对照组,界面纳米渗漏百分比与对照组相比显著增加,Contax黏结强度和界面纳米渗漏百分比与对照组无显著变化.结论:"2步法"自酸蚀黏结剂Contax牙本质黏结界面的耐久性优于"1步法"自酸蚀黏结剂AdperPrompt和全酸蚀黏结剂Prime&Bond NT.     

4种牙色充填材料与乳牙粘结强度的比较研究

目的：比较4种牙色充填材料与乳磨牙的剪切粘结强度,为临床应用提供理论依据。方法：选用滞留乳磨牙80颗,随机分成8组,分别用复合树脂、多聚酸改良复合树脂、树脂改良玻璃离子、玻璃离子及相对应的酸蚀粘结剂或齿面处理剂按使用说明制作牙釉质和牙本质粘结试件,测定其剪切强度,并在体视显微镜下观察试件断面界面破坏情况。结果：4种牙色材料的剪切强度牙釉质组均明显高于牙本质组,复合树脂与多聚酸改良复合树脂组牙质剪切粘结强度无统计学差异,其它任意两组之间均有高度统计学差异。结论：复合树脂与多聚酸改良复合树脂牙质粘结强度无明显差别,均高于玻璃离子和树脂改良玻璃离子,以玻璃离子粘结强度最低。     

酸蚀时间对再矿化牙本质粘结强度影响的研究

目的选取全酸蚀和自酸蚀粘结剂,比较再矿化牙本质在不同酸蚀时间下的粘结强度,为临床上更恰当掌握酸蚀时间提供一定的理论指导。方法选择40颗牙合面慢性龋病达牙本质中层的磨牙,去除病变累及的软化牙本质,保留再矿化牙本质。平行于牙体长轴将牙齿切为3份,分别用35%Gluma酸蚀剂(或处理剂)酸蚀20、40、60 s。选用全酸蚀和自酸蚀牙本质粘结剂分别用于牙本质,树脂恢复牙冠。用低速锯将牙齿片切成横截面积约为1 mm2的长方体状样本,所有样本先在体视显微镜下观察,区分正常牙本质和再矿化牙本质,用微拉伸测试仪检测其粘结强度。结果再矿化牙本质其40 s组的微拉伸强度高于20 s组及60 s组(P<0.05),而60 s组与20 s则无显著差异(P>0.05)。结论酸蚀时间对再矿化牙本质的粘结强度有影响,对再矿化牙本质的酸蚀时间应适当延长。     

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。     

Adhesion of resin composite core materials to dentin

PURPOSE: This study determined (1) the effect of polymerization mode of resin composite core materials and dental adhesives on the bond strength to dentin, and (2) if dental adhesives perform as well to dentin etched with phosphoric acid as to dentin etched with self-etching primer. MATERIALS AND METHODS: Human third molars were sectioned 2 mm from the highest pulp horn and polished. Three core materials (Fluorocore [dual cured], Core Paste [self-cured], and Clearfil Photo Core [light cured]) and two adhesives (Prime & Bond NT Dual Cure and Clearfil SE Bond [light cured]) were bonded to dentin using two dentin etching conditions. After storage, specimens were debonded in microtension and bond strengths were calculated. Scanning electron micrographs of representative bonding interfaces were analyzed. RESULTS: Analysis showed differences among core materials, adhesives, and etching conditions. Among core materials, dual-cured Fluorocore had the highest bond strengths. There were incompatibilities between self-cured Core Paste and Prime & Bond NT in both etched (0 MPa) and nonetched (3.0 MPa) dentin. Among adhesives, in most cases Clearfil SE Bond had higher bond strengths than Prime & Bond NT and bond strengths were higher to self-etched than to phosphoric acid-etched dentin. Scanning electron micrographs did not show a relationship between resin tags and bond strengths. CONCLUSION: There were incompatibilities between a self-cured core material and a dual-cured adhesive. All other combinations of core materials and adhesives produced strong in vitro bond strengths both in the self-etched and phosphoric acid-etched conditions.     

Effect of surface conditioning and restorative material on the shear bond strength and resin-dentin interface of a new one-bottle nanofilled adhesive.

OBJECTIVES: To determine the effect of different combinations of surface conditioning (DeTrey Conditioner 36, NRC, no etching) and restorative materials (Dyract AP, Spectrum TPH) on the shear bond strength of Prime and Bond NT to enamel and dentin, and to characterize the resin-dentin interface produced by these combinations. METHODS: Shear bond strength was tested on 30 enamel and 30 dentin flat labial surfaces of extracted bovine teeth. The enamel and dentin specimens were randomly assigned to six groups of five teeth each and treated using different combinations of surface conditioners and restorative materials with Prime and Bond NT. Scanning electron microscope (SEM) observation of argon-ion-etched specimens was done to evaluate the resin-dentin interface. RESULTS: The type of surface conditioning and restorative material had significant effects on dentin bond strengths. Etching the dentin prior to application of Prime and Bond NT significantly increased bond strength and caused formation of a hybrid layer for Spectrum TPH. For Dyract AP, dentin etching generally did not improve bond strength despite the formation of a hybrid layer. On enamel, Prime and Bond NT had consistently high bond strengths on etched specimens. SIGNIFICANCE: The results showed that Dyract AP and Spectrum TPH, when used with Prime and Bond NT have different bonding mechanisms and the effect of surface conditioning on their shear bond strength differs. Clinicians should be aware of these effects in order to optimize bonding.     

Effect of bonding variables on the shear bond strength and interfacial morphology of a one-bottle adhesive

This study's objectives were: 1) to determine the combination of bonding procedures (with or without acid etching, moist or dry substrate, one or two applications of primer/adhesive) that would produce the highest shear bond strength of Prime & Bond and Dyract AP and 2) to characterize the resin-dentin/enamel interface produced by these bonding procedures. Ninety-six bovine incisors were randomly assigned to eight groups for shear bond testing to enamel (n = 6) and dentin (n = 6). Prime & Bond and Dyract AP were applied and cured following manufacturers' instructions. Shear bond testing was conducted in a Universal Testing Machine. Thirty-two bovine incisors were sectioned to produce blocks with enamel and dentin, then bonded in pairs for evaluation of interfacial morphology. They were polished and argon ion-etched using a high-speed argon ion-etching machine and examined by SEM. The groups where enamel was etched, kept moist or dry and received a single application of Prime & Bond produced the highest shear bond strength. Dentin bond strengths were high in the groups where dentin was etched and kept moist. The number of Prime & Bond applications had no effect on dentin bond strength. Acid etching results in better adaptation of Prime & Bond to enamel and dentin regardless of whether moisture is present.     

Effect of preliminary treatment of the dentin surface on the shear bond strength of resin composite to dentin.

This study evaluated the effect of two dentin disinfectants (Consepsis, Tubulicid), one aqueous HEMA solution (Aqua Prep), a combination of Aqua Prep and Tubulicid and an air abrasion treatment (50 microns aluminum oxide) on the shear bond strength (SBS) of two acetone-based single bottle adhesives (One Step and Prime & Bond 2.1). The occlusal surfaces of 167 freshly extracted human third molars were ground flat to expose the dentin, then polished with a 600 grit-polishing disc. The teeth were randomly assigned to 12 test groups (two bonding agents, six pretreatment protocols). The exposed dentin was etched with 35% phosphoric acid for 20 seconds, rinsed and briefly (1-2 seconds) air dried. Six pretreatment protocols were then applied. The air abrasion groups were exceptional, as etching was carried out only after pretreatment. One Step, or Prime & Bond 2.1 was applied according to the manufacturer's instructions. Cylinders of Z-100 composite were bonded to the flat dentin surfaces by transparent gelatin capsules. Specimens were thermocycled in water baths between 5 degrees and 55 degrees C, then sheared in an Instron Testing Machine. One-way and two-way ANOVA and Tukey HSD post-hoc tests were used for statistical analysis. In the One Step group, Consepsis yielded a significantly higher SBS (17.8 MPa) than air abrasion (9.5 MPa), Control (11.8 MPa) and Aqua Prep + Tubilicid (11.9 MPa), and a comparable SBS with Tubilicid (12.5 MPa) and Aqua Prep (14.8 MPa). In the Prime & Bond 2.1 group, Aqua Prep (24.9 MPa) showed a significantly higher SBS than all other groups: air abrasion (9.3 MPa), Control (9.97 MPa), Tubilicid (12.2 MPa), Consepsis (13.0 MPa) and Tubilicid + Aqua Prep (13.3 MPa).     

Performance and Compatibility of Self Polymerizing Prime and Bond NT Adhesive and the Composite LuxaCore]

AIM: To evaluate the performance of bond strength and the compatibility of Prime &Bond NT self etching adhesive resins without activator on dentin surface with dual composite resin LuxaCore, and verify the contribution of a coactivator. MATERIAL AND METHODS: twenty-four human teeth without decay, molars or pre-molar are used. The dental crowning is cut with diamond disc mounted on a hand piece; the roof surface is flattened and well humidified. Each tooth is embedded in cold self-etching resin (Plexil Excil). Samples are divided into two groups of 12. in the first group, self-etching Prime &Bond NT resin adhesive without activator is supplied on the flat mesial dentin roots, then dual cure composite resin LuxaCore) is bonded. The second group was subject to the same treatment but with addition of co-activator the Prime &Bond NT self-etching adhesive resin. Debonding was achieved with Universal testing machine and mean shear bond strengths were determined for each test group. The data were subjected to ANOVA (p < 0001). RESULT: Bond strength obtained with self-etching Prime &Bond NT without activator is 10.635 MPa. With addition of activator it is 15.185 MPa CONCLUSION: supplementing with an activator has significantly improved bonding strength.     

Acid conditioning combined with single-component and two-component dentin bonding agents.

OBJECTIVE: The purpose of the present study was to compare ethylenediaminetetraacetic acid conditioning and phosphoric acid conditioning of dentin in combination with two principally different commercial dentin bonding systems. METHOD AND MATERIALS: Twenty-one extracted human third molars were used. All teeth were caries free, and no teeth were root filled. In total, 29 pairs of dentin surfaces were obtained from 21 teeth. One dentin surface in each pair was etched with a 32% phosphoric acid gel for 15 seconds, and the opposite surface was etched with a 24% ethylenediaminetetraacetic acid gel for 3 minutes. One experimental group of 15 dentin surface pairs was subsequently bonded with All-Bond 2, a two-component system, and the other group of 14 pairs was bonded with Prime & Bond NT, a one-bottle adhesive. A flowable resin composite was inserted in the experimental cavity and light cured. Shear bond strength testing was performed according to the protocol of the International Organization for Standardization. RESULTS: The combination of conditioning with ethylenediaminetetraacetic acid and bonding with All-Bond 2 was significantly better than all other combinations, providing a shear bond strength that was 61% to 123% greater. CONCLUSION: Use of ethylenediaminetetraacetic acid in combination with All-Bond 2 resulted in a significantly greater bond strength to dentin than did conventional acid etching.     

Evaluating a method of artificially hypermineralizing dentin to simulate natural conditions in bonding studies

PURPOSE: This study tested an in vitro model of dentin hypermineralization, aiming to simulate naturally hypermineralized dentin for bond strength studies. The effect on bond strength of a double-etching treatment on the artificially hypermineralized substrate was also evaluated. MATERIALS AND METHODS: Extracted human third molars were selected and 2 groups were formed: a group of 3 teeth, called N (normal dentin) and a group of 6 teeth, called H (hypermineralized dentin). Occlusal surfaces were ground flat to expose midcoronal dentin. Group H was subjected to artificial hypermineralization and subdivided into 2 subgroups: Ht and Hd. The exposed dentinal surfaces of group N and subgroup Ht were etched with 37% phosphoric acid for 15 s prior to bonding with Single Bond adhesive. Dentin of the subgroup Hd was etched twice (double etching) prior to bonding with Single Bond. A 4-mm-high Z100 composite buildup was created on each tooth and, after 24 h water storage, bond strengths were evaluated by the microtensile method. The data between group N and subgroup Ht and between subgroups Ht and Hd were compared using the Student's t test (alpha = 0.05). RESULTS: No significant difference was observed between bond strengths of group N and subgroup Ht (p = 0.108). Subgroup Hd was statistically different from Ht (p < 0.0001). CONCLUSIONS: Bond strengths of Single Bond to artificially hypermineralized dentin did not differ statistically from those to normal dentin substrate. The double etching approach significantly reduced bond strengths of artificially hypermineralized dentin.     

Shear bond strength of four core materials to dentin bonded with light-cured or dual-cured adhesive

PURPOSE: To measure and compare the shear bond strength of four core materials to dentin bonded with one adhesive (Prime and Bond NT) that was either light-cured or dual-cured. METHODS: The dentin of 80 freshly extracted molars was exposed using a series of abrasive disks. The teeth were divided into eight equal groups, etched with phosphoric acid for 15 seconds and rinsed. Dentin was dried to a moist surface. On 40 teeth, Prime and Bond NT was applied and light-cured for 30 seconds. On 40 teeth, Prime and Bond NT was mixed with the self-cure additive, which was applied to the dentin, and light-cured for 20 seconds. The core materials were then placed following manufacturers' directions onto the cured adhesive. The core material was light-cured, when it was necessary, for 60 seconds and stored for 24 hours in water at room temperature. The specimens were loaded in shear in the Instron until failure at a 5 mm/minute crosshead speed. Data were compared using two factor ANOVA and Tukey's HSD test (P = .05). RESULTS: Both curing mode and core material showed a significant difference. A significant difference between mean shear bond strength for dual and light cured was observed only in CompCore (P = 0.0002). There was no statistical difference when Prime and Bond NT dual-cured was used with chemical- or dual-cured materials.     

Bond strengths of nonrinsing adhesives.

OBJECTIVE: The purpose of this study was to determine enamel and dentin bond strengths of a nonrinsing "all-in-one" adhesive and of a nonrinsing conditioner combined with a 1-bottle adhesive. METHOD AND MATERIALS: Specimens were obtained from 240 bovine teeth ground to expose enamel or dentin surfaces. Ten enamel and 10 dentin specimens were randomly assigned to each of 12 different combinations of adhesive system (Prompt L-Pop; no etch + Prime & Bond NT; NRC + Prime & Bond NT; 36% phosphoric acid + Prime & Bond NT; no etch + Prime & Bond 2.1; 36% phosphoric acid + Prime & Bond 2.1) and restorative material (resin composite; polyacid-modified resin composite ["compomer"]). After the application of the adhesive system, a No. 5 gelatin capsule filled with the restorative material was seated against the enamel or dentin surface. After 24 hours in distilled water at 37 degrees C, the specimens were thermocycled and the shear bond strengths were measured. RESULTS: For resin composite, etching with phosphoric acid resulted in the highest bond strengths to enamel. For compomer, the highest enamel bond strengths were achieved with both phosphoric acid and Prompt L-Pop. Treating dentin with Prime & Bond NT without etching provided the highest mean bond strength for composite. For compomer, treating dentin with Prime & Bond NT resulted in the highest mean bond strengths, regardless of the conditioner. CONCLUSION: Compomer and resin composite exhibited statistically similar bond strengths. Bond strengths to dentin were significantly lower than those to enamel.     

Effect of collagen removal on shear bond strength of two single-bottle adhesive systems

This study evaluated the effect of collagen removal on the shear bond strength for two single-bottle adhesive systems. The ultrastructure of the dentin after treatments and the dentin-resin interface were examined under SEM. The buccal and lingual surfaces of 80 extracted human third molars were ground to expose dentin. Teeth were randomly assigned to four groups and received the following treatments: Group 1(P&B 2.1), Prime & Bond 2.1 adhesive was applied according to the manufacturer's directions and Restorative Z100 composite resin was bonded to the dentin surface; Group 2 (P&B 2.1/NaOCl), the same procedures were followed as for Group 1 except that the surfaces were treated with 10% sodium hypochlorite (NaOCl) for one minute after acid conditioning; Group 3 (SB), Single Bond (3M) was applied according to the manufacturer's recommendations; Group 4 (SB/NaOCl), the same procedure was followed for Group 2, using Single Bond. The specimens were stored in humidity at 37 degrees C for 24 hours and tested in a shear mode at a crosshead speed of 0.5 mm/minute. The Kruskal-Wallis test and Multiple Comparisons were used for statistical analysis of the data. A one-minute exposure of dentin to 10% NaOCl following acid conditioning resulted in a significant increase of the dentin shear bond strength for Prime & Bond 2.1. The same treatment for Single Bond resulted in a significant reduction in bond strength. Groups 1 and 3 were not statistically different from each other. The presence of a collagen layer resulted in the formation of a hybrid layer and similar values of adhesion for both adhesive systems. The results may suggest that collagen removal improves the bond strength for this acetone-based adhesive system but several such systems would need to be investigated.