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。     

自酸蚀树脂水门汀ResiCem牙本质粘结强度的评价

目的 评价自酸蚀树脂水门汀ResiCem的牙本质粘结强度并探讨酸蚀对其粘结强度的影响。方法 选择离体无龋第三恒磨牙15颗。沿垂直于牙体长轴方向将磨牙冠中1/3处切开,将牙本质面分别用自酸蚀树脂水门汀Panavia F和Resi-Cem原位对位粘结。其中ResiCem组牙本质面分别用磷酸酸蚀0、5、10、15 s。用低速切片机把样本切割成约1 mm×1 mm×8mm条块后进行微拉伸测试,并通过扫描电镜观察粘结界面。结果 ResiCem的牙本质微拉伸粘结强度[(16.9±5.3)MPa]与Panavia F[(17.0±5.2)MPa]间差异无统计学意义(P>0.05)。磷酸酸蚀显著地降低ResiCem与牙本质间的粘结强度(P<0.05),并随着酸蚀时间的延长而降低。结论 ResiCem的牙本质微拉伸粘结强度与Panavia F相当,但酸蚀会降低ResiCem的牙本质粘结强度。     

丁香油酚对全酸蚀/自酸蚀牙本质粘接系统微拉伸强度的影响

目的:评价含丁香油酚的暂封剂氧化锌丁香油糊剂(zincoxide- eugenol ,ZOE)对全酸蚀/自酸蚀牙本质粘接系统微拉伸强度的影响。方法:选择因正畸拔除的完整、无龋前磨牙;两种全酸蚀牙本质粘接系统:AllBond 2和SingleBond ,两种自酸蚀牙本质粘接系统:ClearfilSEBond和iBond。实验组使用氧化锌丁香油糊剂;对照组牙本质表面不做任何处理;分别存储于3 7℃的蒸馏水中,一周后两组分别使用4种牙本质粘接系统,用微拉伸法测试粘接强度。在体视显微镜下观察断裂界面。结果:双因素方差分析使用ZOE对粘接强度有显著影响(P <0 .0 5 ) ,粘接剂的类型对粘接强度无显著性影响(P >0 .0 5 ) ,交互作用有统计学意义(P <0 .0 5 )。多重比较提示,AllBond 2和SingleBond的实验组和对照组无显著性差异,而ClearfilSEBond和iBond实验组的微拉伸强度明显低于对照组,有显著性差异。体视显微镜下观察断裂多发生在粘接剂内。结论:含丁香油酚的暂封剂氧化锌丁香油糊剂对全酸蚀系统的AllBond 2和SingleBond的粘接强度无影响,对自酸蚀系统的ClearfilSEBond和iBond有显著不利影响。     

矿化液对牙本质粘接系统粘结强度的影响

目的:研究矿化液在牙本质粘接中的作用,同时了解经过蛋白萃取剂处理牙本质后牙本质混和层再矿化是否受影响。方法:选择人正常双尖牙40颗去除牙合面釉质后随机分4组,制得酸蚀标本分别进行常规树脂修复 硅油浸泡(A组),常规树脂修复 人工唾液浸泡(B组),常规树脂修复 矿化液浸泡(C组)和NaC l溶液(蛋白萃取剂) 常规树脂修复 矿化液浸泡(D组)。12周后用能谱仪观察粘结界面混合层再矿化情况,同时用微拉力仪对牙本质粘结系统的粘结强度进行测试。结果:经矿化液浸泡组混合层钙磷比值显著升高(P<0.05),但0.5 mol/L NaC l溶液对混合层钙磷无影响(P>0.05),同时经矿化液浸泡组和硅油浸泡组的牙本质粘结系统微拉伸强度无统计学意义(P>0.05),但均显著高于人工唾液浸泡组(P<0.05)。结论:矿化液对牙本质粘结系统混合层的脱矿牙本质有再矿化作用,可相对提高粘结微拉伸强度;而0.5 mol/L NaC l溶液对增加牙本质粘结混合层再矿化能力无明显作用。     

白酸蚀粘结系统的使用方法对牙本质粘结强度的影响

目的：评价自酸蚀粘结系统中不同的使用方法对牙本质粘结强度的影响。材料与方法：将255颗拔出的牛牙颊面进行研磨以暴露出平坦的牙本质表面,再将牙齿分成4个实验组,使用4种自酸蚀粘结系统．分别为One Up Bond F Plus, Clearfil SE Bond Xeno Ⅲ．以及FuturaBondNR．对照组为传统的酸蚀;中洗粘结系统Adper Single Bond 2。所有实验组均主动或被动地使用一或两层的自酸蚀粘结剂．再将复合树脂粘结至牙本质．24h后在一个万能试验机上以1mm／min的速度对试样进行剪切测试。对得到的数据进行双因素方差分析．Dunnett以及Tukey检验（5％）。结果：不同的粘结剂类型、使用方法以及相互作用等因素间均有显著性的差异。所有粘结系统均表现出显著差异．主动使用两层自酸蚀粘结剂产生的平均粘结强度要明显高于被动使用的。结论：主动使用自酸蚀粘结剂能有效增加牙本质的剪切粘结强度,而且不同的使用方法对粘结的影响取决于所测试的粘结剂类型。     

预酸蚀对非龋性硬化牙本质黏结强度的影响

目的：评价预酸蚀处理提高3种自酸蚀黏结剂对牙颈部非龋性硬化牙本质黏结的有效性。方法：选择牙颈部有典型硬化牙本质的离体牙29个，其中24个随机分3组，每组8个牙，分别应用黏结剂Contax、Clearfil TRI—S Bond及Xeno Ⅲ，剩余5个牙用来观察硬化牙本质表面微观结构。以等分硬化牙本质的方式纵向切开每个牙齿，一半先用350g／L磷酸酸蚀15s，然后应用黏结剂，另一半直接应用黏结剂。在黏结剂上充填复合树脂并固化，24h后片切制作微拉伸黏结试件，测试拉伸黏结强度，并在扫描电镜下观察断裂面。结果：Contax与Clearfil TRI—S Bond2种黏结剂的预酸蚀组的黏结强度明显高于未预酸蚀黏结组（P〈0．01），XenoⅢ预酸蚀组与未预酸蚀黏结组拉伸黏结强度无显著性差异（P〉0．05）。结论：用350g／L的磷酸预酸蚀能够提高一些自酸蚀黏结剂对非龋性硬化牙本质的黏结强度。     

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。     

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。     

不同酸蚀方法对非龋性硬化牙本质黏结强度的影响

目的:测试不同酸蚀方法处理非龋性硬化性牙本质对黏结强度的影响,为临床工作提供参考.方法:牙颈部具有典型楔状缺损的前磨牙共30颗,随机分为2大组,分别应用全酸蚀黏结系统AdperTM Single Bond2 (ASB2)与自酸蚀黏结系统AdperTM Easy one(AEO),每大组各分为3个亚组(ASB21、ASB22、ASB23、AEO1、AEO2、AEO3),每亚组5颗牙.其中,ASB21组:磷酸处理15s后ASB2处理15s,ASB22组:磷酸处理30 s后ASB2处理15s,ASB23组:磷酸处理15s后ASB2处理30 s;AEO11组:AEO1处理20 s;AEO2组:AEO处理40 s;AEO3组:磷酸处理15s后AEO处理20s.进行树脂充填后,室温下放入蒸馏水中24 h后取出,制作成黏结面积为1 mm2的哑铃型试件,微力材料试验机测量各试件的微拉伸黏结强度.采用SPSS17.0软件包对数据进行单因素方差分析,多重比较采用SNK-q检验.结果:各组微拉伸黏结强度依次为AEO3组＞ASB22组＞ASB23组＞ASB21组＞AEO2组＞AEO1组,AEO3组的黏结强度最高,AEO1组最低,差异显著(P＜0.05);ASB22组黏结强度低于AEO3组高于其他组,差异显著(P＜0.05).结论:使用全酸蚀黏结系统.加倍延长磷酸处理时间,黏结强度增加.使用自酸蚀黏结系统,联合磷酸处理或延长自酸蚀黏结剂处理时间,均会使黏结强度增加.其中,磷酸处理硬化性牙本质15s联合自酸蚀黏结剂处理20s获得的黏结强度最高.无论使用全酸蚀系统或自酸蚀系统,磷酸处理硬化性牙本质15s联合自酸蚀黏结剂处理20 s获得的强度最好,单独使用自酸蚀黏结系统黏结强度最差.     

Primary dentin etching time,bond strength and ultra-structure characterization of dentin surfaces

Objectives

To evaluate the effect of shortening the etching time on roughness, microhardness and bond strength of three adhesive systems to primary tooth dentin.

Methods

Flat dentin surfaces from primary molars were randomly assigned to six experimental groups. Three different adhesive systems were used: an etch-and-rinse adhesive (Single Bond), a two-step self-etching (Clearfil SE Bond), and a one-step self-etching (One-Up Bond F) adhesive. In half of the specimens, the recommended etching time was used, in the other half the etching time was 50% reduced. After applying the adhesive, resin composite build-ups were constructed and stored in a humid environment for 24 h at 37 °C. Specimens were sectioned into 1 mm² beams and tested for microtensile bond strength (MTBS). Debonded surfaces were analyzed by scanning electron microscopy (SEM). Additional surfaces were conditioned for microhardness measurements (KHN) and for atomic force microscopy (AFM) analysis. Intertubular and total surface roughness (Ra) were recorded. Results were analyzed with ANOVA and Student–Newman–Keuls tests (P < 0.05).

Results

Single Bond and Clearfil SE Bond showed higher MTBS than One-Up Bond F. Bond strength and intertubular roughness increased when Single Bond and One-Up Bond F were used with a reduced etching time. For Clearfil SE Bond no differences in MTBS were detected when reducing the etching time. The application of phosphoric acid, Clearfil SE Bond primer and One-Up Bond F decreases dentin microhardness.

Conclusions

Shortening One-Up Bond F application time and reducing the etching time of phosphoric acid to one-half of the manufacturer's recommended etching time when using Single Bond are recommended when bonding to primary dentin.     

Shortening of primary dentin etching time and its implication on bond strength

OBJECTIVE: The aim of this study was to investigate the influence of shortening the etching time on the bond strength of a conventional and a self-etching primer adhesive system used in primary tooth dentin. METHODS: Flat dentin surfaces were obtained from 24 primary molars, randomly assigned to 4 experimental groups. The adhesive systems Single Bond and Clearfil SE Bond were applied in two groups according to the manufacturers' recommendations. In the other two groups, the adhesives were applied after half-time of acid etching, 7 s for Single Bond and 10 s for Clearfil SE Primer. Resin crowns were built up and after 24 h storage in water at 37 degrees C, the teeth were sectioned to produce beams with cross-sectional area of approximately 0.49 mm2. Specimens were tested in tension at 0.5 mm/min until failure. Fractured specimens were analyzed to determine the failure mode. RESULTS: Tensile bond strengths for Single Bond in primary dentin were higher than for Clearfil SE Bond. Shortening of acid etching time improved bond strength only for Single Bond, while no statistically significant difference was observed for Clearfil SE Bond when both etching times were compared. SIGNIFICANCE: No detrimental effect on bond strength was observed when the time of acid etching was shortened in 50%. Shortening the time for a procedure in a small child without compromising the quality of the work is a very important finding for the practicing pediatric dentist.     

Evaluation of etching time on dentin bond strength using single bottle bonding systems

PURPOSE: Incomplete infiltration of the demineralized collagen network may result in a weak zone within the hybrid layer and between the hybrid layer and dentin. The current study evaluates whether reducing the etching time to 5 s from the recommended 15 s or increasing it to 30 s has an effect on dentin bonding. MATERIALS AND METHODS: 108 extracted molars were assigned to 3 bonding agent groups (n = 36): (a) Single Bond (SB), (b) One-Step (OS), and (c) Syntac Single Component (SSC). Each group was further divided into three subgroups (n = 12) of different etching times: 5, 15, and 30 s. All groups were bonded with Z100 composite resin according to the manufacturer's instructions. All specimens were thermocycled 300 times between +/-5 degrees C and +/-55 degrees C, and shear bond strength testing and mode of failure analysis were performed. RESULTS: The bond strength of SB (5 s: 15.5 MPa +/- 4.4; 15 s: 16.5 MPa +/- 3.1; 30 s: 16.8 MPa +/- 3.2) and OS (5 s: 13.7 MPa +/- 1.8; 15 s: 12.4 MPa +/- 3.8; 30 s: 10.6 MPa +/- 3.8) showed no significant differences (p < 0.05) for the different etching times. For SSC, different etching times showed significant differences (5 s: 10.9 MPa +/- 1.8; 15 s: 7.5 MPa +/- 2.5; 30 s: 6.4 MPa +/- 2.1). The mode of failure for SB and OS was adhesive or mixed adhesive/cohesive. For SSC, all failures were adhesive. CONCLUSION: Etching times of less than 15 s do not seem to adversely affect bonding to dentin.     

Effect of primer dwell time on dentin bond strength

The period of time that primers are to be applied to etched dentin surfaces is sometimes clear and sometimes not indicated in the instructions accompanying the bonding system. In this study, primers with either alcohol or acetone solvents appeared to act rapidly and not show any significant improvement with extended primer dwell time. When resin adhesive primer application periods were prolonged, significant improvements in the bond strengths of some adhesives occurred. Water-based primers placed on dried etched dentin surfaces appear to require longer application times than do acetone or alcohol-based primers applied to wet etched dentin surfaces. Careful attention is required regarding the application of these materials. If in doubt about the primer application, longer primer application periods should be used.     

Effects of etching time of primary dentin on interface morphology and microtensile bond strength

OBJECTIVES: To determine the influence of different etching times (5, 15 or 30 s) on the morphology and micro-tensile bond strength (muTBS) of primary dentin. METHODS: For muTBS study, nine primary molars were randomly distributed in three experimental groups. Three Class I cavities per tooth were drilled and etched (37% orthophosphoric acid gel for 5, 15 or 30 s). Excite adhesive was applied and cavities restored with a resin composite (Tetric Ceram). Composite/dentin bars (ca. 1 mm2 section) were obtained from teeth and tested in tension until debonding. Means of muTBS results were compared with ANOVA and Student-Neuman-Keuls post hoc tests. Morphology: Three occlusal cavities were prepared in five primary molars. Each cavity was etched and restored as described for previous groups and teeth were sectioned mesio-distally. One half of each tooth was prepared for using under optical microscopy using Masson's trichromic dye technique and the other half was examined by SEM. RESULTS: muTBS mean (S.D.) results (in MPa) were 5 s etch: 6.20 (2.81), 15 s: 13.43 (5.91), 30 s: 13.04 (5.67). muTBS groups were Excite 5 s < Excite 15 s = Excite 30 s. Masson's trichromic technique stained the demineralized dentin layer red in all specimens. The mean (S.D.) thickness of the demineralized layers (in mu) were 5 s: 3.28 (1.23), 15 s: 3.83 (1.26), 30 s: 4.44 (1.70). There is a statistically significant linear relationship between time of application of etching and mean depth of demineralized layer. This relationship was established as depth (in mu) = 3.08 + 0.05 time (in s). SIGNIFICANCE: The minimum adequate etching time for primary dentin is 15s.     

Effect of air-drying time of single-application self-etch adhesives on dentin bond strength

This study examined the effect of air-drying time of adhesives on the dentin bond strength of several single-application self-etch adhesive systems. The adhesive/resin composite combinations used were: Adper Prompt L-Pop/Filtek Z250 (AP), Clearfil Tri-S Bond/Clearfil AP-X (CT), Fluoro Bond Shake One/Beautifil (FB), G-Bond/Gradia Direct (GB) and One-Up Bond F Plus/Palfique Estelite (OF). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied according to each manufacturer's instructions followed by air-drying time for 0 (without air-drying), 5 and 10 seconds. After light irradiation of the adhesives, the resin composites were condensed into a mold (phi4x2 mm) and polymerized. Ten samples per test group were stored in 37 degrees C distilled water for 24 hours; they were then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Tukey's HSD tests (alpha = 0.05) were done. FE-SEM observations of the resin/dentin interface were also conducted. Dentin bond strength varied with the different air drying times and ranged from 5.8 +/- 2.4 to 13.9 +/- 2.8 MPa for AP, 4.9 +/- 1.5 to 17.1 +/- 2.3 MPa for CT, 7.9 +/- 2.8 to 13.8 +/- 2.4 MPa for FB, 3.7 +/- 1.4 to 13.4 +/- 1.2 MPa for GB and 4.6 +/- 2.1 to 13.7 +/- 2.6 MPa for OF. With longer air drying of adhesives, no significant changes in bond strengths were found for the systems used except for OF. Significantly lower bond strengths were obtained for the 10-second air-drying group for OF. From FE-SEM observations, gaps between the cured adhesive and resin composites were observed for the specimens without the air drying of adhesives except for OF. The data suggests that, with four of the single-application self-etch adhesive systems, air drying is essential to obtain adequate dentin bond strengths, but increased drying time does not significantly influence bond strength. For the other system studied, the bond strength of the non-air dried group was not significantly different from the five second drying time, but prolonged drying was very detrimental to bond strength. For all five of the systems studied, a five-second air-drying time appeared to be appropriate.     

Influence of post-bleaching time intervals on dentin bond strength

It has been reported that bond strength of resin to tooth structure can be reduced when the bonding procedure is carried out immediately after the bleaching treatment. This study evaluated the effect of bleaching of non-vital teeth bleaching on the shear bond strength (SBS) of composite resin/bovine dentin interface and the influence of delaying the bonding procedures for different time intervals following internal bleaching. According to a randomized block design, composite resin cylinders (Z100/Single bond - 3M) were bonded to the flattened dentin surface of two hundred and fifty-six teeth which had previously been subjected to four different treatments: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP - 37% carbamide peroxide; and CON - distilled water (control), each one followed by storage in artificial saliva for 0 (baseline), 7, 14, and 21 days after bleaching (n = 16). The bleaching agents in the pulp chambers were replaced every 7 days, over 4 weeks. The SBS test of the blocks was done using a universal testing machine. The ANOVA showed that there was no significant interaction between time and bleaching agents, and that the factor time was not statistically significant (p > 0.05). For the factor bleaching treatment, the Student's t-test showed that [CON = CP] > [SPW = SPH]. The bleaching of non-vital teeth affected the resin/dentin SBS values when sodium perborate mixed with 30% hydrogen peroxide or water was used, independently of the elapsed time following the bleaching treatment.     

Effect of irradiation time to light-cured resin composite on dentin bond strength.

This study examined the relationship between the irradiation time of three light-cured resin composites and their bond strength to dentin using two adherend surfaces. The light-cured resin composite systems selected were: Scotchbond/Silux, Scotchbond 2/Silux, and Clearfil Photo Bond/Photo Clearfil A. The adherend surfaces selected were a flat dentin surface and a box-shaped cavity. The greatest bond strength for all resin systems was recorded using the longest irradiation time. The bond strengths increased with an elevated irradiation time. When comparing the flat surface and a box-shaped cavity, the bond strength of the box cavity was greater than the flat surface with similar conditions except for 20 and 30 seconds of Scotchbond and 30 seconds of Clearfil. The correlation between bond strength and irradiation was greater for the flat surface than for the box-shaped cavity. This implied that the bond strength of the box-shaped cavity may be more susceptible to polymerization shrinkage.