湿度对"单瓶"牙本质粘结系统微拉伸粘结强度的影响

目的用微拉伸强度检测法评价脱矿牙本质表面的不同"湿度"状态对酒精/水基和丙酮基"单瓶"牙本质粘结系统粘结强度的影响.方法选择40颗健康前磨牙,去除牙合面釉质,随机均分为8个实验组,在过湿、用滤纸吸干、用空气干燥1 s或用空气干燥30 s的脱矿牙本质上分别应用Single Bond或Prime&Bond NT单瓶牙本质粘结系统.将牙齿片切为粘结面积约0.9 mm×0.9 mm的长方体状样本,进行微拉伸粘结强度检测,对结果进行统计学分析.结果对于同一种粘结系统,其吸干组和1 s干燥组间的微拉伸粘结强度值无统计学差异,但均显著高于过湿组和30 s干燥组.结论脱矿牙本质表面的湿度对酒精/水基和丙酮基"单瓶"牙本质粘结系统的粘结强度有极大的影响.     

丙酮基和酒精-水基牙本质粘接系统粘接强度比较及粘接界面观察

目的:比较丙酮基和酒精-水基两种不同溶剂类型的全酸蚀牙本质粘接系统粘接强度和粘接界面的微观形态。方法:选择24颗正畸治疗拔除的健康前磨牙,去除合面釉质层,随机分两组,每组选用一种 “两步法”全酸蚀牙本质粘接系统:以丙酮为溶剂的Prime & Bond NT(PB组)和以酒精和水为溶剂的Single Bond 2(SB2)组,粘接后进行微拉伸力检测。以扫描电镜(SEM)和激光共聚焦扫描电镜(LCSM)观察两种牙本质粘接系统的粘接界面。结果:粘接强度PB组(29.49±4.01) MPa,SB2组微拉伸粘接强度为,SB2组为(30.03±4.33) MPa,无统计学差异。两种牙本质粘接系统均可充分渗入脱矿牙本质表层的胶原纤维网和牙本质小管内,形成混合层和树脂突,SB组混合层薄而均匀,树脂突长。结论:不同溶剂类型的两组牙本质粘接系统微拉伸粘接强度无差异,全酸蚀牙本质粘接系统在湿粘接状态下可以对牙本质形成良好的渗透。     

Effects of different re-wetting techniques on dentin shear bond strengths

PURPOSE: For contemporary hydrophilic resin adhesive systems, bonding to dentin is improved if the substrate is maintained in a hydrated state following acid-etching. The purpose of this study was to compare the dentin shear bond strengths of two single-bottle adhesives (one acetone-based and one ethanol-based) applied under different etched-dentin conditions: dry, wet, or dry and re-wetted with different solutions. MATERIALS AND METHODS: Bovine incisors (N = 120) were mounted in acrylic, polished to 600-grit, and randomly assigned to 12 groups (n = 10). Dentin was etched for 15 seconds using 35% phosphoric acid, rinsed, and either blot-dried, air-dried, or air-dried and re-wetted with different solutions (distilled water, Gluma Desensitizer, Aqua-Prep, and 5% glutaraldehyde in water). Two adhesives (Single Bond and Prime & Bond NT) were applied to each of the surface conditions following manufacturers' instructions. After adhesive application and curing, composite was applied in a No. 5 gelatin capsule and light-cured. Specimens were loaded in shear, using an Instron at 5 mm per minute. Shear bond strengths were calculated by dividing the failure load by the bonded surface area. Data were subjected to analysis of variance (ANOVA) and a post hoc Tukey test. RESULTS: Mean shear bond strengths ranged from 12.5 to 26.6 MPa for Single Bond and from 5.6 to 14.7 MPa for Prime & Bond NT. Significant differences were found in both groups of materials (p < .001). The three highest mean bond strengths were obtained (in order) on dentin that was re-wetted with Gluma Desensitizer, re-wetted with Aqua-Prep, or never dried. Differences between these surface conditions were not statistically significant for either material.     

In vivo influence of residual moisture on microtensile bond strengths of one-bottle adhesives

Purpose: This study evaluated the microtensile bond strengths of three dentin adhesives applied on clinically moist dentin or on dentin that was dried with air for 5 seconds. The null hypothesis to test was that the level of residual moisture does not influence bond strengths when restorations are placed in vivo.
Materials and Methods: Twenty-four premolars scheduled to be extracted for orthodontic reasons from patients between the ages of 15 and 23 years were restored with one of the following adhesive systems followed by a mini hybrid composite resin: Excite (Ivoclar/Vivadent), an ethanol-based dentin adhesive; Prime & Bond NT (Dentsply/Caulk), an acetone-based dentin adhesive; and Single Bond (3M ESPE), an ethanol and water-based dentin adhesive. After extraction, the specimens were sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.7 ± 0.2 mm². The specimens were attached to a Geraldeli device and fractured using a universal testing machine at a crosshead speed of 1 mm per minute.
Results: For each dentin adhesive, there were no statistical differences between means for dry dentin versus moist dentin. Single Bond and Prime & Bond NT ranked in the same statistical subset regardless of the moisture condition of the substrate. Both Excite, dry, and Excite, moist, resulted in statistically lower bond strengths than Single Bond, moist, but similar to those of Single Bond, dry, Prime & Bond NT, moist, and Prime & Bond NT, dry.
CLINICAL SIGNIFICANCE
In this study, the level of residual moisture did not influence microtensile bond strengths. Clinically, the degree of moisture left on the dentin surface upon rinsing off the etching gel may not be as relevant as previously reported in laboratory studies.     

Effect of solvent and rewetting time on dentin adhesion.

OBJECTIVE: The purpose of this in vitro study was to determine the influence of solvent and rewetting time on microtensile dentin bond strengths of four dentin adhesives. METHOD AND MATERIALS: Sixty human molar specimens were divided into four dentin adhesive treatment groups: (1) a water-based total-etch dentin adhesive, EBS Multi; (2) an ethanol-based total-etch adhesive, Excite; (3) an acetone-based total-etch adhesive, Prime & Bond NT; and (4) an ethanol- and water-based total-etch adhesive, Single Bond. For each dentin adhesive, three specimens were assigned to five dentin moisture conditions. Specimens were tested in the tensile mode. RESULTS: When adhesives were applied to moist dentin, bond strengths varied from 26.2 MPa for Prime & Bond NT to 29.5 MPa for Single Bond without any statistical differences. When applied to dentin that had been dried for 15 seconds, Prime & Bond NT and Excite resulted in the lowest mean bond strengths, but they were statistically similar to each other (7.9 and 8.3 MPa, respectively). Single Bond resulted in a mean bond strength of 12.7 MPa, which was significantly lower than that of EBS Multi (24.1 MPa). For the latter, all mean bond strengths were statistically similar when some amount of moisture was present on the surface. For the other three adhesives, mean bond strengths returned to the range obtained on moist dentin only when dentin was rewet for 30 seconds. CONCLUSION: Bond strengths upon rewetting depend on the type of solvent in the bonding system, and rewetting time.     

Effect of residual water on dentin bond strength and hybridization of a one-bottle adhesive system

This research investigated the effects of wet and dry conditions of phosphoric acid etched dentin on resin bonding and determined the optimum moisture condition for resin bonding using an ethanol-based one-bottle adhesive system. Bovine dentin surfaces were etched with 35% phosphoric acid and rinsed with water. Under four wet and dry conditions (overwet, blot dry, one-second dry and desiccated), resin composite was bonded using Single Bond. Tensile bond strength was measured and the results analyzed by one-way ANOVA and Fisher's PLSD test at the 5% level. The resin-dentin interfaces of bonded specimens were observed with SEM. The bond strength of overwet, blot dry, one-second dry and desiccated groups were 5.2 MPa, 12.6 MPa, 11.9 MPa and 4.4 Mpa, respectively. The blot dry group and one-second dry groups revealed significantly higher bond strengths than the desiccated and overwet groups (p < 0.05). The formation of hybrid layers approximately 5 microm thick (overwet and blot dry), 2 microm (one-second dry) and 3 microm (desiccated) were observed. The coefficient of variation in the blot dry group was very high, even though a higher mean was observed. In the one-second dry group, the moisture content of the collagen network was possibly too low, such that hybrid layer formation was not as good even though the bond strength was high.     

Stability of wet versus dry bonding with different solvent-based adhesives.

OBJECTIVE: To evaluate the effects of surface moisture (wet or dry) and storage (24h or 3 months) on the microtensile bond strength (BS) of resin/dentin bonds mediated by two water/ethanol based adhesives Single Bond, 3M-ESPE, (SB) and Opti Bond Solo Plus, Kerr, (OB), and two acetone-based adhesives, One Step, Bisco, (OS) and Prime&Bond NT, Caulk/Dentsply, (PB). MATERIALS AND METHODS: Flat dentin surfaces were polished with 600-grit SiC paper, etched with 35% phosphoric acid for 15s and rinsed for 20s. Half the surface was maintained moist and the other half was air-dried for 30s. Each adhesive was applied simultaneously to both halves, left undisturbed for 30s and light-cured. Four-mm resin build-ups were constructed incrementally. After storage in water at 37 degrees C for 24h, slabs were produced by transversal sectioning and trimmed to an hourglass shape (0.8mm2). Half of the specimens were tested in tension at 0.6mm/min immediately after trimming and the other half after 3 months of water storage. Data were analyzed by two-way ANOVA and SNK for each material. RESULTS: Both moisture and storage affected BS to dentin, and was material-dependent. Dry bonding affected mostly the acetone-based adhesives. Larger reductions in bond strength were associated with dry bonding after 3 months of water storage. SIGNIFICANCE: Wet bonding resulted in more stable bonds over 3 months of water storage for most of the materials tested.     

Effect of various surface treatments on the microleakage and ultrastructure of resin-tooth interface

This study evaluated the effect of collagen removal and sodium ascorbate treatment of acid-etched dentin on the microleakage and ultrastructure of resin-tooth interface under moist and dry conditions using an acetone-based 1 bottle adhesive system. Class V cavities were made on the buccal surfaces of 90 premolars scheduled for orthodontic extraction. The cavities were etched with 37% phosphoric acid (DPI tooth conditioning gel/India) for 15 seconds. The teeth were divided into six groups with 15 teeth each. In Group 1, the etched surface was blot dried with a dry cotton pellet, leaving it visibly moist, and Prime & Bond NT (Dentsply Detrey/ Germany) was applied. In Group 2, after acid conditioning, the cavity surface was air dried for five seconds, followed by application of Prime & Bond NT. In Group 3, 3% NaOCl (Hyposol, Prevest Denpro Ltd/India) was applied to the acid-conditioned cavity surface for two minutes. The surface was blot dried before bonding. In Group 4, after NaOCl treatment, the surface was air dried for five seconds, followed by application of the bonding agent. In Group 5, 10% sodium ascorbate (chemically pure) was applied to the NaOCl-treated acid conditioned tooth surface for one minute. The surface was blot dried before bonding. In Group 6, after sodium ascorbate treatment as in Group 5, the cavity surface was air dried for five seconds before bonding. The cavities were restored with the hybrid composite Spectrum TPH (Dentsply Detrey, Konstanz, Germany). The teeth were extracted immediately after restoration, and the specimens were prepared for microleakage testing using 2% methylene blue dye and for scanning electron microscopic evaluation. The results of the dye penetration were analyzed with Kruskal-Wallis non-parametric analysis followed by the Mann-Whitney U test at a significance level of p = 0.05. After acid etching, the conventional acid etched groups and groups with NaOCl treatment demonstrated extensive leakage. Sodium ascorbate treatment of the NaOCl-treated dentin significantly reduced microleakage. No statistically significant difference between moist and dry bonding was observed in all groups. Although resin tag penetration improved in both the NaOCl-treated and NaOCl/ascorbate-treated groups, an absence of gap at the resin dentin interface was observed only for the NaOCl/ascorbate-treated groups.     

Effect of solvent type on microtensile bond strength of a total-etch one-bottle adhesive system to moist or dry dentin

This study evaluated the effect of organic solvent (acetone or ethanol) on the microtensile bond strengths (MTBS) of an adhesive system applied to dry and moist dentin. Sixteen extracted human third molars were ground to expose a flat occlusal dentin surface and acid etched for 20 seconds (20% phosphoric acid gel, Gluma Etch 20 Gel, Heraeus/Kulzer). After rinsing the acid etchant, an ethanol-based one-bottle adhesive system was applied to the mesial half of the occlusal dentin surface. An acetone-based, one-bottle adhesive system was applied to the distal half of the ground dentin surface. The teeth were randomly assigned to groups. In Group 1, the etched dentin was thoroughly air dried and an ethanol-based one-bottle adhesive system was applied (Gluma Comfort Bond, Heraeus/Kulzer) (GCB). In Group 2, the etched dentin was thoroughly air dried and an acetone-based one-bottle adhesive system was applied (Gluma One Bond, Heraeus/Kulzer)(GOB). In Group 3, excess moisture was removed after acid etching, leaving a moist dentin surface and a one-bottle ethanol-based adhesive was applied (Gluma Comfort Bond). In Group 4, excess moisture was removed after acid etching, leaving a moist dentin surface and an acetone-based adhesive was applied (Gluma One Bond). A hybrid resin composite (Venus, Heraeus/Kulzer) was applied to the bonded surface in four 1-mm increments and light cured according to manufacturer's directions. The specimens were then sectioned with a slow-speed diamond saw in two perpendicular directions to obtain sticks with a cross-section of 0.5 +/- 0.05 mm2. The microtensile bond strength (MTBS) test was performed with a Bencor device in an Instron machine at a crosshead speed of 0.5 mm/minute. The data were subjected to a two-way ANOVA and Scheffé Post hoc test (p < 0.05). The experimental MTBS measured for dry dentin were Group 1 = 37.0 +/- 10.6 and Group 2 = 34.7 +/- 9.0 in MPa (mean +/- SD); and on moist dentin, Group 3 = 50.7 +/- 11.0 and Group 4 = 38.5 +/- 10.5 in MPa (mean +/- SD). The ethanol based adhesives resulted in higher MTBS than acetone-based adhesive (p < 0.008) and bonding to moist dentin resulted in higher MTBS (p < 0.001). GCB applied on moist dentin resulted in statistically higher bond strengths than the other groups. The highest MTBS were achieved with the use of an ethanol-based adhesive to moist dentin.     

Effect of Polymerization Mode on Bond Strengths of Resin Adhesive/Cement Systems

PURPOSE: The purpose of this study was to examine the effect of resin adhesive/cement system primer and cement polymerization mode (auto- vs dual-polymerized) on the shear bond strength to dentin. MATERIALS AND METHODS: Dentin surfaces of 90 bovine teeth were polished to 600 grit. The dentin was etched for 15 seconds with phosphoric acid, rinsed, and blotted. Three adhesive systems, All-Bond 2, Prime & Bond 2.1 Dual-Cure, or Scotchbond Multi-Purpose Plus, were applied. Three primer polymerization methods were used with each system: dual-polymerized, autopolymerized, or strictly following manufacturers' recommendations. Resin cements, which were also either auto- or dual-polymerized, were applied to dentin using gelatin capsules. Shear bond strengths were determined using an Instron universal testing machine. RESULTS: The greatest bond strength, 15.4 MPa, was found with the Scotchbond system when the primer was dual-polymerized and the cement was autopolymerized. The lowest bond strength, 7.5 MPa, was found with All-Bond 2/Duo-Link, when the primer and cement were dual-polymerized. The autopolymerization mode produced the highest mean bond strength for All-Bond 2, while dual-polymerization of primer and cement resulted in the highest mean bond strength for Prime & Bond 2.1. Scotchbond Multi-Purpose Plus was least affected by the polymerization method. Two-way ANOVA showed that the interaction between the type of adhesive system and the method of polymerization significantly influenced bond strength (p = .0001). CONCLUSIONS: The effect of the primer polymerization method on ultimate bond strength was different for each adhesive system evaluated. More research is needed to elucidate the interaction between adhesive system and method of polymerization on bonding of resin cements to dentin.     

牙本质表面状态对酒精-水基粘接剂强度和界面影响的微拉伸及LSCM研究

目的 :研究干燥或湿润的牙本质表面状态对酒精 -水基粘接剂粘接强度和粘接界面微观结构的影响 ,并探讨粘接强度和粘接界面微观结构之间的内在联系。方法 :选用两种含有酒精和水的湿粘接系统OptiBondSolo和SingleBond ,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 ,并在激光扫描共聚焦显微镜下观察和比较各组试件粘接界面超微结构的异同。结果 :湿粘接时粘接剂对牙本质表面的渗透较为充分 ,混合层均匀 ,厚度约为 5 μm ,并可观察到牙本质小管和侧支小管中均有明显的树脂突形成 ;干燥粘结时形成的界面形态与湿粘接时没有明显区别。干燥粘接时 ,两种粘接系统的微拉伸强度均有显著降低 ,下降幅度最高为 2 3 % ,微拉伸破坏的方式主要是粘接界面的破坏。结论 :含有酒精和水的粘接系统在干燥或湿润粘接时粘接界面的超微结构变化不明显 ,其中的水分对干燥的牙本质表面有再湿润效果 ;干燥粘结时微拉伸强度则有明显的降低 ;微拉伸强度的测试可以更客观的反映粘接强度的大小。     

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。     

Shear Bond Strengths of One-Bottle Adhesives to Moist Enamel

Abstract: Purpose: This study evaluated bond strengths of six one-bottle bonding agents and a control (primer plus unfilled resin) to moist enamel.
Materials and Methods: One-hundred and five bovine teeth were randomly assigned to seven groups of 15. Enamel was etched for 15 seconds with 35% phosphoric acid. Etched enamel was rinsed, and excess water was blotted with tissue paper. Following application of the adhesive, composite resin was bonded using a gelatin capsule technique. Shear bond strengths to enamel were determined using a universal testing machine (Instron Corp., Canton, Massachusetts).
Results: Mean bond strengths ranged from 21.9 MPa for OptiBond Solo (Kerr Corp., Orange, California) to 29.6 MPa for Prime & Bond 2.1 (Dentsply/Caulk, Milford, Delaware). Prime & Bond 2.1 had a significantly higher mean bond strength than the other adhesives.
CLINICAL SIGNIFICANCE: The results of this study suggest that all of the one-bottle systems tested should provide clinically acceptable bonding to moist enamel.     

Shear bond strengths of one-bottle adhesives to moist enamel.

PURPOSE: This study evaluated bond strengths of six one-bottle bonding agents and a control (primer plus unfilled resin) to moist enamel. MATERIALS AND METHODS: One-hundred and five bovine teeth were randomly assigned to seven groups of 15. Enamel was etched for 15 seconds with 35% phosphoric acid. Etched enamel was rinsed, and excess water was blotted with tissue paper. Following application of the adhesive, composite resin was bonded using a gelatin capsule technique. Shear bond strengths to enamel were determined using a universal testing machine (Instron Corp., Canton, Massachusetts). RESULTS: Mean bond strengths ranged from 21.9 MPa for OptiBond Solo (Kerr Corp., Orange, California) to 29.6 MPa for Prime & Bond 2.1 (Dentsply/Caulk, Milford, Delaware). Prime & Bond 2.1 had a significantly higher mean bond strength than the other adhesives. CLINICAL SIGNIFICANCE: The results of this study suggest that all of the one-bottle systems tested should provide clinically acceptable bonding to moist enamel.     

Effects of saliva contamination on shear bond strength of compomer to dentin in primary teeth

PURPOSE: To investigate the effects of saliva contamination on the bond strengths of two compomers applied to primary teeth dentin during different bonding stages. METHODS: 30 extracted human non-carious primary molars were prepared for shear bond-strength testing. Specimens were randomly divided into three groups of 10. Prime & Bond NT (acetone-based) and Futura Bond A & B (water-based) adhesives were tested under the following conditions: (a) non-contaminated conditions; (b) after contamination of the dentin surface with fresh whole saliva for 20 seconds and removal of excess saliva before adhesive application; and (c) contamination of the dentin surface with fresh whole saliva for 20 seconds and removal of excess saliva after adhesive curing. Following adhesive application Dyract AP or Glasiosite was applied via a polytetrafluroethylene split mould and light-cured to the dentin surface. Shear bond strengths were measured using an Instron Universal testing machine running at a crosshead speed of 1 mm/minute. After measuring shear bond strengths, specimens were prepared for SEM evaluation and identification of failure type. Results were analyzed by two-factor experiment with repeated measures as one factor. RESULTS: No statistically significant differences were found among the shear bond strengths (P > 0.05) of the groups. The results revealed that saliva contamination of dentin surfaces before or after adhesive application did not affect the shear bond strength of either compomer.     

牙本质的表面状态对黏接剂粘接强度的影响

目的研究3种不同的表面状态对两种牙本质黏接剂的粘接强度的影响。方法选用两种牙本质粘接系统SingleBond(SB)和Prime&BondNT(PB),分别应用于干燥、湿润和过湿的离体的人牙本质表面,用Z-100树脂恢复牙冠至4mm。用低速锯片切牙齿,精细金刚砂车针修成沙漏状的粘接面积约0.8mm2的样本,测试各个样本的微拉伸粘接强度。结果两种黏接剂在湿润状态下的粘接强度均高于干燥组和过湿组(P<0.05),干燥组与过湿组的差异无显著性。在3种表面状态下,SB的粘接强度均高于PB组(P<0.05)。结论在使用全酸蚀单瓶粘接系统时,牙本质表面必须保持适度的湿润。     

The effect of a re-wetting agent on dentin bonding.

OBJECTIVES: Recently, a new generation of simplified one-bottle dentin bonding systems, sensitive to variations in the degree of substrate moisture, was introduced. This in vitro project compared the dentin bond strengths and interfacial ultra-morphology formed by three one-bottle bonding systems [OptiBond SOLO (ethanol-based), Prime&Bond 2.1 (acetone-based), and Single Bond (ethanol- and water-based)]. The null hypothesis tested was that re-wetting a dried dentin surface with a HEMA aqueous solution would not result in bond strengths, and resin impregnation into demineralized dentin, comparable to those obtained for moist dentin. METHODS: Dentin specimens were assigned to the following three etched surface conditions: moist dentin-control group; dentin dried for 5 s; and dentin dried for 5 s and re-moistened with a commercial 35% HEMA aqueous solution. Mean shear bond strengths were calculated and analyzed with one- and two-way ANOVA. Dentin discs treated with the same combination of surface condition/adhesive were processed and observed under both transmission and scanning electron microscopes. RESULTS: For moist dentin, the morphology of the resin-dentin interfaces showed penetration of the dentin adhesives to the depth of the transition between demineralized and unaffected dentin. Drying dentin for 5 s resulted in a significant decrease in mean bond strengths and an incompletely infiltrated collagen structure with areas of unveiled collagen fibers, regardless of the solvent. Re-wetting dentin with the aqueous HEMA solution re-established the level of bond strengths obtained to moist dentin and resulted in a raise of the fiber network with simultaneous increase in interfibrillar space dimensions. SIGNIFICANCE: The results suggest that the use of an aqueous HEMA solution might compensate for the dryness induced on dentin surfaces by using air blasts from an air syringe, after rinsing off the etchant. As the behavior of the material that contained water was also affected by surface dryness, the percentage of water included in the composition of current ethanol- and water-based adhesives, such as Single Bond, may not be enough to compensate for the collapse of the collagen filigree upon drying.     

表面状态对乙醇-水基黏接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乙醇 -水基黏接剂黏接强度与黏接界面微观结构的影响 ,探讨黏接强度与黏接界面微观结构之间的内在联系。方法　选用两种含有乙醇和水的湿黏接系统OptiBondSolo和SingleBond ,将Chrisma树脂分别黏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 ,并在扫描电镜下观察和比较各组试件黏接界面超微结构的异同。结果　湿黏接时黏接剂对牙本质表面的渗透较为充分 ,混合层均匀 ,厚度为 4～ 5 μm ,并可观察到牙本质小管和侧支小管中均有明显的树脂突形成 ;干燥黏结时形成的界面形态与湿黏接时没有明显区别。干燥黏接时 ,两种黏接系统的微拉伸强度均降低 ,下降幅度最高为 2 3% ,微拉伸破坏的方式主要是黏接界面的破坏。结论　微拉伸强度测试可客观反映黏接强度的大小     

The effect of nonvital bleaching on the shear bond strength of composite resin using three adhesive systems

PURPOSE: To evaluate the effect of nonvital bleaching on the shear bond strength of composite resin using three adhesive systems. MATERIALS AND METHODS: Two hundred seventy bovine teeth were assigned to 3 groups (n = 90): SP, paste of sodium perborate and water; CP, 37% carbamide peroxide; CO, control group (no treatment). After the bleaching treatment, the teeth in each group were cut into enamel (E) and dentin (D) sections. The teeth were embedded in polyester resin and polished in order to obtain a flat E or D surface. Each group was divided into 6 subgroups (n = 15) according to substrate (E and D) and adhesive system: SB, Single Bond (solvent: water/alcohol); PB, Prime & Bond NT (solvent: acetone); CLF, Clearfil SE Bond (solvent: water). The adhesive system was applied on each flat surface according to the manufacturer's instructions and a cylinder of composite resin Z-250 was overlaid. The specimens were stored in distilled water for 7 days at 37 degrees C. The SBS test was performed in a universal testing machine with crosshead speed of 0.5 mm/min. The data obtained (in MPa) were statistically analyzed with two-way ANOVA and Tukey's test (p < or = 0.05). RESULTS: The bleaching treatment influenced the SBS, regardless of the adhesive system used. On enamel, the SP and CP bleaching treatments reduced the SBS values. On dentin, the SP bleaching agent reduced the SBS values, but the CP bleaching did not. CONCLUSION: Nonvital bleaching treatment with sodium perborate may adversely affect shear bond strength of composite resin for both enamel and dentin. Similar effects can be expected from 37% carbamide peroxide bleaching agent on enamel but not dentin bonding strength. The use of water/alcohol and acetone-based adhesive systems cannot reverse the effects of bleaching treatments on bond strengths.