The microtensile bond strength of self-etching adhesives to ground enamel

It is uncertain whether single-phase self-etching adhesives form bonds to enamel as reliable as those of etch-and-rinse adhesives. This study compared the microtensile bond strengths to ground enamel of three self-etching adhesive systems, a self-etching primer system and an etchand-rinse adhesive system. Human enamel was ground flat with 320-grit silicone carbide paper. The self-etching adhesives iBond (Heraeus Kulzer), Prompt L-Pop (3M ESPE) and Xeno III (Caulk/Dentsply), the adhesive with a self-etching primer Clearfil SE Bond (Kuraray) and the etch-and-rinse adhesive Scotchbond Multipur-pose (3M/ESPE) were applied as directed, followed by a core of the same manufacturers' hybrid resin composite. A microtensile bond strength evaluation was performed after 48 hours of water storage, using untrimmed beams approximately 0.9 mm2 in cross-sectional area at a crosshead speed of 0.6 mm/minute. There were no pretest failures in any group, and failures were predominately adhesive or mixed. Adhesion to enamel of Clearfil SE was not significantly different from Scotchbond Multi-Purpose, while the three self-etching adhesive systems demonstrated significantly lower bond strengths (One-way ANOVA, Tukey-Kramer Multiple-Comparison Test, p < 0.00001).     

Effect of water storage on bond strength of self-etching adhesives to dentin

AIM: The objective of this study was to evaluate the bond strength of self-etching adhesive systems one week and one year after storage in water. METHODS AND MATERIALS: Fragments from the buccal surfaces of 45 bovine teeth were prepared (12 mm in length x 5 mm in width x 1.0 mm in thickness). Dentin surfaces were wet-abraded with 600-grit SiC paper to create a standardized smear layer. Samples were randomly assigned to 18 experimental groups (n=5), according to nine adhesive systems tested (Single Bond; Adper Prompt L-Pop; iBond; One-Up Bond F; Xeno III; Clearfil SE Bond; Optibond Solo Plus SE; Tyrian SPE/One-Step Plus; and UniFil Bond) and two water-storage times (one week and one year). Adhesives were applied according to the manufacturers' instructions. Z250 composite was applied into the molds to fill up the internal diameter volume of a Tygon tubing mold (1.0 mm high/0.7 mm internal diameter). Micro-shear bond strengths were determined using an apparatus attached to an Instron Universal Testing Machine (0.5 mm/min). Data were statistically analyzed using a two-way analysis of variance (ANOVA) and the Tukey's test (5%). RESULTS: One year after water storage the dentin bond strength of all adhesive systems reduced significantly, except for One-Up Bond F. CONCLUSION: Water-storage time decreased the bond strength for most dentin bonding agents tested.     

The effect of direct and indirect water storage on the microtensile dentin bond strength of a total-etch and two self-etching adhesives

PURPOSE: To evaluate the effect of direct and indirect water storage on the microtensile dentin bond strength of one total-etch and two self-etching adhesives. METHODS: The adhesive materials were: one total-etch adhesive; Admira Bond and two self-etch adhesives; Clearfil SE Bond and Hybrid Bond. Freshly extracted human third molar teeth were used. In each tooth, a Class I cavity (4 x 4 mm) was prepared in the occlusal surface with the pulpal floor extending approximately 1 mm into dentin. The teeth were divided into three groups (n = 12). Each group was restored with the resin composite Clearfil APX using one of the tested adhesives. For each experimental group three test procedures (n = 10) were carried out: Procedure A: the teeth were stored in water for 24 hours, then sectioned longitudinally, buccolingually and mesiodistally to get rectangular slabs of 1.0 - 1.2 mm thickness on which a microtensile test was carried out; Procedure B: the teeth were also sectioned, however the slabs were stored in water at 37 degrees C for 1 year before microtensile testing; Procedure C: the teeth were kept in water at 37 degrees C for 1 year before sectioning and microtensile testing. During microtensile testing the slabs were placed in a universal testing machine and load was applied at a cross-head speed of 0.5 mm/minute. RESULTS: For the 24-hour water storage groups there was no significant difference in bond strength between the three adhesives. After 1 year of indirect water storage, the bond strength decreased but the reduction was not significantly different from those of 24 hours. After 1 year of direct water storage, the mean bond strengths of Admira Bond and Hybrid Bond were significantly reduced compared to their 24-hour results. In contrast the average value of Clearfil SE Bond was not significantly affected.     

Influence of hydrostatic pulpal pressure on the microtensile bond strength of all-in-one self-etching adhesives

PURPOSE: To evaluate the microtensile bond strength (microTBS) of two all-in-one self-etching adhesive systems and two self-etching adhesives with and without simulated hydrostatic pulpal pressure (PP). MATERIALS AND METHODS: Flat coronal dentin surfaces of extracted human molars were prepared. Two all-in-one self-etching adhesive systems, One-Up Bond F (OBF; Tokuyama) and Clearfil S3 Bond (Tri-S, Kuraray Medical) and two self-etching primer adhesives, Clearfil Protect Bond (PB; Kuraray) and Clearfil SE Bond (SE; Kuraray) were applied to the dentin surfaces according to manufacturers' instructions under either a pulpal pressure (PP) of zero or 15 cm H2O. A hybrid resin composite (Clearfil AP-X, Kuraray) was used for the coronal buildup. Specimens bonded under PP were stored in water at 37 degrees C under 15 cm H2O for 24 h. Specimens not bonded under PP were stored under a PP of zero. After storage, the bonded specimens were sectioned into slabs that were trimmed to hourglass-shaped specimens, and were subjected to microtensile bond testing (microTBS). The bond strength data were statistically analyzed using two-way ANOVA and the Holm-Sidak method for multiple comparison tests (alpha = 0.05). The surface area percentage of different failure modes for each material was also statistically analyzed with three one-way ANOVAs and Tukey's multiple comparison tests. RESULTS: The microTBS of OBF and Tri-S fell significantly under PP. However, in the, PB and SE bonded specimens under PP, there were no significant differences compared with the control groups without PP. CONCLUSIONS: The microTBS of the two all-in-one adhesive systems decreased when PP was applied. However, the microTBS of both self-etching primer adhesives did not decrease under PP.     

Effects of one-year storage in water on bond strength of self-etching adhesives to enamel and dentin

The aim of this study was to compare the bond strengths of three self-etching materials during one year of storage. Clearfil SE Bond (SE), Clearfil Protect Bond (PB), and Clearfil Tri-S Bond (TS) were used for bonding to dentin and enamel according to manufacturer's instructions. Microshear bond strength values were measured after 24 hours, six months, and one year. Two-way ANOVA showed that the interaction of material type and storage time was significant for dentin. At baseline, SE had the highest bond strength to dentin. There were no significant changes in bond strength for each material during the storage period, except for PB which showed increased bond strength to dentin after one year. All materials performed reliably after one year. However, the antibacterial and fluoride-releasing effects of PB would further contribute to the long-term clinical benefits of this material.     

Influence of air abrasion and long-term storage on the bond strength of self-etching adhesives to dentin

This study tested the effects of long-term storage and aluminum oxide air abrasion on the bond strength of self-etching adhesive systems. Extracted human third molars were ground flat with 600-grit SiC paper to expose middle coronal dentin. Clearfil SE Bond and One-Up Bond F were applied to dentin surfaces in accordance with manufacturers instructions with or without previous aluminum oxide 50 microm air abrasion. A crown was built up with the resin composite TPH Spectrum and the specimens were stored in water for 24 hours. The bonded assemblies were vertically sectioned into beams for microtensile bond testing. The beams of each tooth were individually immersed in bottles containing water at 37 degrees C for one day, three and six months; the water was changed daily. The specimens were then subjected to microtensile bond testing. The bond strength data were subjected to ANOVA and Tukey Kramer test. Fractured specimens were analyzed in a scanning electron microscope to determine failure modes. Air abrasion improved Clearfil SE Bond bond strength in the three month evaluation. No significant difference was found between the two adhesives systems, but bond strengths gradually decreased over time. Failure modes varied significantly among groups and were influenced by long-term storage and aluminum oxide air abrasion.     

Influence of thermal and mechanical load cycling on the microtensile bond strength of self-etching adhesives

PURPOSE: To evaluate the influence of thermal and mechanical load cycling on the microtensile dentin bond strength of two self-etching and one total-etch adhesives. METHODS: The adhesive materials were: a two-step self-etch adhesive (Clearfil SE Bond), a one-step self-etch adhesive (Hybrid Bond), and a total-etch one-step adhesive (Admira Bond). Sixty freshly extracted human third molars were used. In each tooth, a Class I cavity (4 x 4 mm) was prepared in the occlusal surface with the pulpal floor extending about 1 mm into dentin. The teeth were divided into three groups (n=20). Each group was restored with the resin composite Clearfil APX using one of the adhesives. After restoration, 10 teeth in each group were thermocycled between 5 degrees C and 55 degrees C, (dwell time 3 minutes, 5,000 cycles). The same teeth were then mounted in a fatigue loading machine to receive an intermittent load of 125 N at 52 cycles/minute for 4,000 cycles. Subsequently, each tooth was sectioned longitudinally, bucco-lingually and mesio-distally to get rectangular slabs 1-1.2 mm in thickness for the microtensile test. Each slab was then placed in a universal testing machine and tensile load was applied at a cross-head speed of 0.05 mm/minute. RESULTS: Without loading procedures, there was no significant difference in the bond strength of the tested adhesives. In contrast to Admira Bond and Clearfil SE Bond, fatigue loading resulted in a significant reduction of the bond strength for Hybrid Bond when compared to the unloaded restorations.     

Effect of blood contamination with 1-step self-etching adhesives on microtensile bond strength to dentin

This study evaluated the effect of blood contamination and decontamination methods on the microtensile bond strength of 1-step self-etching adhesive systems to dentin contaminated after adhesive application and light curing. Three commercially available "all-in-one" adhesives (One Up Bond F, Xeno III and Adper Prompt L-Pop) and 1 resin composite (Clearfil AP-X) were used. Third molars that had been stored in distilled water with 0.5% thymol at 4 degrees C were ground with #600 SiC paper under running water to produce a standardized smear layer. The specimens were randomly divided into groups according to the 3 adhesive systems. The adhesive systems were used under 3 conditions: no contamination, which was the control (C); contamination of the light-cured adhesive surface with blood and reapplication of adhesive (Contamination 1) and contamination of the light-cured adhesive surface with blood, then washing, drying and reapplication of the adhesive (Contamination 2). Following light curing of the adhesive, the resin composite was placed in 3 increments up to a 5-mm-thick layer on the bonded surface. All specimens were stored in distilled water at 37 degrees C for 24 hours. The microtensile bond strength was measured using a universal testing machine (EZ test), and data were analyzed by 1-way ANOVA followed by the Duncan test to make comparisons among the groups (p=0.05). After debonding, 5 specimens were selected from each group and examined in a scanning electron microscope to evaluate the modes of fracture. For all adhesives, contamination groups showed lower bond strength than the control (p<0.05). There was no statistically significant difference among the control groups (p>0.05). For Xeno III and Adper Prompt L-Pop, contamination group #2 showed the lowest bond strength among the groups (p<0.05). For One Up Bond F, contamination group #2 showed higher bond strength than contamination group #1 but showed no statistical significance between them (p>0.05).     

自酸蚀粘结系统及唾液污染分别对窝沟封闭剂微拉伸粘结强度的影响

目的 评价Clearfil S3 Bond自酸蚀粘结系统和唾液污染对窝沟封闭剂拉伸粘结强度的影响.方法 15颗离体前磨牙,随机分为3组,每组5颗.A、B组分别经35%磷酸酸蚀、Clearfil S3 Bond自酸蚀处理,C组35%磷酸酸蚀后唾液污染,3组均用Estiseal F窝沟封闭剂分层固化堆积形成5 mm高封闭剂小柱.再将样本切成1 mm×1 mm×10 mm大小的试件,微拉伸仪检测其拉伸粘结强度.结果 使用自酸蚀粘结系统与常规磷酸酸蚀组的微拉伸粘结强度无显著区别(P＞0.05),而唾液污染组显著低于常规磷酸酸蚀组的微拉伸粘结强度(P＜0.05).结论 临床操作过程中应严格避免唾液污染,而关于自酸蚀粘结剂对封闭剂与牙釉质的微拉伸粘结强度的影响需进一步研究.     

Effect of hydrostatic pulpal water pressure on microtensile bond strength of self-etch adhesives to dentin

PURPOSE: To evaluate the effect of pulpal pressure on the microtensile bond strength of four self-etch adhesives to dentin. A total-etch adhesive was added for comparison. METHODS: 60 freshly extracted human third molars were selected. For each tooth, the root was removed below the cemento-enamel junction. A second parallel section was made to remove the coronal enamel to form a crown segment. The root portion of the resulting crown segment was cemented to a Plexiglas platform using cyanoacrylate cement. The crown segment was then connected with a plastic tube to a water column to produce a pressure of 20 cm H2O at the prepared dentin surface of the crown segment. The adhesive materials were: a total-etch adhesive (Scotchbond 1) and four self-etch adhesives (Clearfil SE Bond, Hybrid Bond, Futurabond NR, and AdheSE Bond). The tested adhesives were applied to the dentin surface in three test procedures: applied to dentin without pulpal pressure, applied to dentin with pulpal pressure for 24 hours, and applied to dentin with pulpal pressure and the pressure was maintained for 6 months during storage. Grandio resin composite was placed in 3-4 layers to a height of 5-6 mm to form a crown segment. For bond strength measurement, the composite-dentin segment was removed from the Plexiglas. This segment was then sectioned to prepare the specimens for microtensile bond measurement. RESULTS: None of the tested adhesives showed bond strength reduction when applied to dentin supplied with water pressure. After 6 months of pulpal pressure, Scotchbond 1, Clearfil SE Bond and AdheSE Bond showed significant reduction in bond strength (P < 0.05). In contrast, Futurabond NR and Hybrid Bond were not significantly affected.     

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。     

Effect of different bur grinding on the bond strength of self-etching adhesives

This study compared the microtensile bond strength (MTBS) of three all-in-one adhesive systems and a two-step system using two types of burs to prepare the dentin surfaces. Flat coronal surfaces of 24 extracted human molars were produced using either regular-grit or superfine-grit diamond burs. Resin composite was then bonded to equal numbers of these surfaces using one of the four adhesives: Clearfil SE Bond (CSE), G-Bond (GB), SSB-200 (SSB) or Prompt L-Pop (PLP). After storage for 24 hours in 37 degrees C distilled water, the bonded teeth were sectioned into slices (0.7-mm thick) perpendicular to the bonded surface. The specimens were then subjected to microtensile testing and the bond strengths were calculated at failure. Bond strength data were analyzed by two-way ANOVA and the GamesHowell test for interaction between adhesive and type of cut dentin. The fractured surfaces were observed by SEM to determine the failure mode. In addition, to observe the effect of conditioning, equal numbers of the two bur-cut dentin surfaces of eight additional teeth were conditioned with the adhesives and observed by SEM. Based on the results, when CSE and SSB were bonded to dentin cut with a regular-grit diamond bur, the MTBS values were significantly lower than that of superfine bur-cut dentin; whereas, GB and PLP showed no significant differences in MTBS between the two differently cut surfaces. SEM observation of the fractured surfaces revealed a mixed mode (adhesive in some areas and cohesive in others in the same sample) of failure in all specimens except PLP, which showed cohesive failure within the adhesive for both types of bur preparation. Generally, SEMs of the conditioned surfaces using both types of burs showed partial removal of the smear layer for CSE, minimal for GB and SSB and complete removal for PLP. In conclusion, when cutting dentin, selecting the proper bur type is important for improving the bond strength of some self-etching adhesive systems.     

Effect of dentinal surface preparation on bond strength of self-etching adhesives

PURPOSE: This study examined the effects of cutting dentin with different burs at various speeds on the microtensile bond strength (muTBS) of two self-etching adhesive systems. MATERIALS AND METHODS: Flat deep dentin surfaces from 50 extracted human third molars were divided into 5 groups (n = 10) according to bur type and speed of rotation: (I) high-speed diamond bur, (II) low-speed diamond bur, (III) high-speed tungsten carbide bur, (IV) low-speed tungsten carbide bur. Controls were abraded with 600-grit SiC paper. A two-step self-etching adhesive, Clearfil SE Bond (SE, Kuraray) and a one-step self-etching adhesive, Clearfil S3 Bond (S3, Kuraray) were applied to dentin surfaces and light cured. Composite buildups were performed using Filtek Z250 (3M ESPE). For lTBS evaluation, composite-dentin beams of 0.8 mm2 were stressed to failure at a crosshead speed of 1 mm/min. The muTBS data were analyzed using two-way ANOVA and Tukey's multiple comparison tests. Representative fractured beams from each group were prepared for fractographic analysis under SEM. RESULTS: Two-way ANOVA showed that the effects of dentin surface preparations, adhesive systems, and their interaction were statistically significant (p < 0.001). The muTBS was the highest when bonding SE to dentin surface prepared with 600-grit SiC abrasive paper (47.3 +/- 7.4 MPa), followed by high-speed tungsten carbide burs (40.8 +/- 6.1 MPa), and the lowest when bonding S3 to dentin surfaces prepared with a high-speed diamond bur (15.2 +/- 6.2 MPa). SEM observation of the fractured surfaces revealed mixed and adhesive failures for SE groups, while in the S3 groups, adhesive failures predominated with numerous inclusion droplets. CONCLUSION: Higher bond strengths are achieved with SE bond when applied on dentin surfaces prepared with tungsten carbide burs. Proper bur and adhesive selection are essential to optimize dentin adhesion of self-etching adhesives.     

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。     

Resin-dentin interfacial ultrastructure and microtensile dentin bond strength after five-year water storage

OBJECTIVE: To evaluate a total-etch three-step adhesive system's resin-dentin interfacial ultrastructure and microtensile dentin bond strength (microTBS) after multi-year storage in water. METHODS: Resin composite crowns were formed on 600 grit SiC flattened extracted human molars using a total-etch three-step adhesive system (Optibond FL, Kerr) and a hybrid resin composite (Prodigy, Kerr). microTBS specimens were fabricated and placed in water with 0.5% chloramine T at 37 degrees C until respective static load to failure testing at one-month, six-months and five-year storage. Failure modes were determined by scanning electron microscopy. The interfacial ultrastructure of the resin-dentin interface was analyzed by transmission electron microscopy (TEM) at 48-hours and 44-months storage. microTBS was modeled with Weibull distribution for survival analysis and failure curve distributions were analyzed by the Wald chi-square statistic for significant differences at alpha=0.05. RESULTS: The characteristic tensile strength (sigma omicron) at one-month, six-months and five-year storage was 52.63, 14.77 and 23.57 Mpa, with a Weibull modulus of 3.04, 1.56 and 1.28, respectively. Failure distributions for all groups were significantly different (p<0.0001) with one-month > five-year > six-months. TEM interfacial morphology demonstrated hydrolytic degradation of hybrid layer components at 44-months storage. SIGNIFICANCE: The decrease in tensile strength and changes in ultrastructure may be caused by water sorption and resultant hydrolytic degradation of the adhesive joint.