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。     

Effects of adhesive primers on bond strength of self-curing resin to cobalt-chromium alloy

Purpose. This study evaluated the effects of four adhesive primers on the shear bond strength of a self-curing resin to cobalt-chromium alloy.Material and methods. The adhesive primers Acryl Bond (AB), Cesead Opaque Primer (COP), Metal PrimerII (MPII), and MR Bond (MRB) were used. A brass ring placed over the casting alloy disk surface nonprimed or primed with each primer was filled with the self-curing methyl methacrylate–polymethyl methacrylate resin. The specimens were stored in water at 37° C for 24 hours and then alternately immersed in water baths at 4° C and 60° C for 1 minute each for up to 20,000 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min.Results. All the primers examined improved the shear bond strength between the resin and cobalt-chromium alloy compared with nonprimed specimens before thermal cycling. However, after 20,000 thermal cycles, the bond strengths of resin to cobalt-chromium alloy primed with COP or MPII primers were significantly greater than those of specimens primed with AB or MRB primers and nonprimed controls.Conclusion. This study indicated that COP and MPII are effective primers to obtain higher bond strength between resin and cobalt-chromium alloy.     

Effects of incremental curing on contraction stresses associated with various resin composite buildups.

OBJECTIVE: The purpose of this study was to photoelastically evaluate contraction stresses associated with various resin composite build-up procedures, including incremental curing and the use of flowable composite for pulpless molars. METHOD AND MATERIALS: Life-sized photoelastic models of an endodontically treated molar were fabricated. The cavity represented a conservative access preparation and included four lateral walls. The following materials were used for buildup: dual-cured hybrid composite (Cleafil DC Core [DC], BIS-CORE [BC]); light-cured flowable composite (AELITEFLO LV [ALV]); and chemical-cured flowable composite (CORE-FLO [CF]). The photoelastic models were built up with the following techniques: bulk-cured (BDd [dual-cured DC], BDc [chemically-cured DC], BBd [dual-cured BC], and BC [CF]); and incremental-cured (1 mm gingivally + 3.5 mm occlusally; IAB [ALV + BC], ICB [CF + BC], and IBB [BC + BC]). Isochromatic fringes developed in the models were recorded photographically in the field of a circular polariscope, and maximum fringe order was determined. Five specimens were tested for each condition. RESULTS: Stress intensity of the build-up methods fell into two categories: high (BDd, BBd, BC, and IAB) and low (BDc, ICB, and IBB). The difference between high and low groups was statistically significant, except between BC and ICB. The maximum fringe order was developed around the point angles at the cavity floor for all the conditions tested. CONCLUSIONS: Type and setting mechanism of resin composite build-up technique had considerable influence on contraction stress. Incremental buildup using composites with low elastic modulus did not reduce contraction stress intensity compared with bulk-cured techniques.     

Influence of curing rate of resin composite on the bond strength to dentin

This study determined whether the strength with which resin composite bonds to dentin is influenced by variations in the curing rate of resin composites. Resin composites were bonded to the dentin of extracted human molars. Adhesive (AdheSE, Ivoclar Vivadent) was applied and cured (10 seconds @ 1000 mW/cm2) for all groups. A split Teflon mold was clamped to the treated dentin surface and filled with resin composite. The rate of cure was varied, using one of four LED-curing units of different power densities. The rate of cure was also varied using the continuous or pulse-delay mode. In continuous curing mode, in order to give an energy density totaling 16 J/cm2, the power densities (1000, 720, 550, 200 mW/cm2) emitted by the various curing units were compensated for by the light curing period (16, 22, 29 or 80 seconds). In the pulse-delay curing mode, two seconds of light curing at one of the four power densities was followed by a one-minute interval, after which light cure was completed (14, 29, 27 or 78 seconds), likewise, giving a total energy density of 16 J/cm2. The specimens produced for each of the eight curing protocols and two resin composites (Tetric EvoCeram, Ivoclar Vivadent; Filtek Supreme XT, 3M ESPE) were stored in water at 37 degrees C for seven days. The specimens were then either immediately subjected to shear bond strength testing or subjected to artificial aging (6,000 cycles between 5 degrees C and 55 degrees C baths) prior to testing. Failure modes were also assessed. The shear bond strengths were submitted to factorial analysis of variance, and the failure modes were submitted to a Chi-square test (alpha = 0.05). All but power density (curing mode, resin composite material and mode of aging) significantly affected shear bond strength. The curing mode and resin composite material also influenced the failure mode. At the selected constant energy density, pulse-delay curing reduced bonding of the resin composite to dentin.     

The effect of additional etching and curing mechanism of composite resin on the dentin bond strength

PURPOSE

The aim of this study was to evaluate the effects of additional acid etching and curing mechanism (light-curing or self-curing) of a composite resin on the dentin bond strength and compatibility of one-step self-etching adhesives.

MATERIALS AND METHODS

Sixteen human permanent molars were randomly divided into eight groups according to the adhesives used (All-Bond Universal: ABU, Clearfil S3 Bond: CS3), additional acid etching (additional acid etching performed: EO, no additional acid etching performed: EX), and composite resins (Filtek Z-250: Z250, Clearfil FII New Bond: CFNB). Group 1: ABU-EO-Z250, Group 2: ABU-EO-CFNB, Group 3: ABU-EX-Z250, Group 4: ABU-EX-CFNB, Group 5: CS3-EO-Z250, Group 6: CS3-EO-CFNB, Group 7: CS3-EX-Z250, Group 8: CS3-EX-CFNB. After bonding procedures, composite resins were built up on dentin surfaces. After 24-hour water storage, the teeth were sectioned to make 10 specimens for each group. The microtensile bond strength test was performed using a microtensile testing machine. The failure mode of the fractured specimens was examined by means of an optical microscope at ×20 magnification. The data was analyzed using a one-way ANOVA and Scheffe''s post-hoc test (α=.05).

RESULTS

Additional etching groups showed significantly higher values than the no additional etching group when using All-Bond Universal. The light-cured composite resin groups showed significantly higher values than the self-cured composite resin groups in the Clearfil S3 Bond.

CONCLUSION

The additional acid etching is beneficial for the dentin bond strength when using low acidic one-step self-etch adhesives, and low acidic one-step self-etch adhesives are compatible with self-cured composite resin. The acidity of the one-step self-etch adhesives is an influencing factor in terms of the dentin bonding strength and incompatibility with a self-cured composite resin.     

3种树脂表面处理技术对树脂核-玻璃离子水门汀粘接强度影响的实验研究

目的 比较3种表面处理的树脂核与玻璃离子水门汀间的剪切粘接强度,为临床上设计树脂核-全冠修复体时冠的粘接提供理论依据。方法 将30个树脂核试件块随机分为3组：金刚砂车针打磨（RDB）组、RDB加酸蚀剂酸蚀（RDBE）组、RDB加树脂粘接剂（RDBA）组,分别接受金刚砂车针打磨、RDB加酸蚀剂酸蚀、RDB加树脂粘接剂3种表面处理。将各组树脂核与玻璃离子水门汀粘接,经37 ℃恒温水浴24 h后,测试分析各组的剪切粘接强度,并通过扫描电镜依次观察树脂核表面形貌、粘接界面及粘接断面,记录粘接面破坏形式。结果 3组的树脂核表面形貌及粘接界面形貌不同,而粘接断面的断裂方式无统计学差异（P>0.10）。RDB组、RDBE组、RDBA组试件的剪切强度分别为（4.28±0.18）、（4.65±0.17）、（2.39±0.21）MPa,3组间的剪切强度具有统计学差异（P<0.01）。结论 树脂核表面处理对其与玻璃离子水门汀间的剪切粘接强度有影响。     

Influence of different light curing units on the bond strength of indirect resin composite restorations

The aim of this study was to evaluate the influence of different light sources on the bond strength of indirect resin composite restorations cemented with a dual-cure resin cement. The superficial dentin of human third molars was exposed and acid-etched and an adhesive system was applied (Single Bond 2). Four-mm-thick indirect resin composite restorations (Gradia) were fabricated and cemented using a dual-cure resin cement (Rely X). Four light sources were used to polymerize the cement: QTH - Optilux 401; LED1 - L.E.Demetron 1; LED2 - Optilight CL; and LED3 - Ultralume 5. The teeth were stored for 24 h and then sectioned, yielding stick-shaped specimens for each group with a bonded area of 1.0 mm(2). The specimens were then tested in a universal testing machine, at a crosshead speed of 1 mm/min. Data were analyzed using ANOVA. Bond strength mean values were: QTH: 22.5 (+/- 8.4); LED1: 22.7 (+/- 9.4); LED2: 21.4 (+/- 10.2); and LED3: 27.3 (+/- 13.8). No statistically significant difference was observed among the experimental groups. The bond strength values when the cement was polymerized using different LED lights were equivalent to the values when the QTH light was used. It can be concluded that the variety of light sources used in the present study did not influence the bond strength of indirect resin composite restorations cemented with a dual-cure resin cement.     

Effects of composite thickness on the shear bond strength to dentin

The manufacturers of some condensable posterior composites claim that their products can be placed in bulk and light-cured in 5-mm-thick increments. This study compared the shear bond strengths of three composite resins when bonded to dentin in 2- and 5-mm-thick increments. Overall the bond strengths were adversely affected by the composite thickness (p < 0.0001). The shear bond strength of each composite tested was much lower when polymerized in a 5-mm increment than in a 2-mm increment of composite (p < or = 0.0005). The two condensable composites tested had a lower bond strength than the conventional composite when polymerized in a 5-mm bulk increment (p < or = 0.01).     

自凝水凝胶义齿软衬材料粘结强度实验研究

目的　探讨自凝水凝胶软衬材料与义齿基托之间的粘结强度 ,并评价水份存在对该材料粘结强度的影响。同时将其与硅橡胶和自凝丙烯酸酯类软衬的粘结强度作比较。方法　用牙科型盒通过常规方法制备基托试样 ,使其长为 40mm ,粘结面为 10mm× 10mm。两粘结面之间预留 3mm间隙 (用金属模型 ) ,充填软衬材料 ,使其在室温下固化。用LJ - 5 0 0型拉力试验机测试软衬与基托粘结强度。结果　自凝水凝胶软衬的粘结强度明显优于SDG -A硅橡胶及自凝型丙烯酸酯类软衬 ,高达 5 .433Mpa。当浸入 37℃蒸馏水中 1d、3d ,其值有不同程度下降 ,并于第 3d后趋于稳定。结论　自凝水凝胶软衬材料具有很高的粘结强度 ,但水对其有一定影响。     

Effects of different pretreatments on the bond strength of a dual-cure resin core material to various fiber-reinforced composite posts

The aim of this study was to evaluate the effects of different pretreatments on the bond strength of a dual-cure resin core to 3 types of fiber posts. Bond strength was measured using a push-out design. One-sided t-Test of Hypothesis with unknown variance was performed (p-values < 5%). Sandblasting abrasion with 50 micro alumina particles at a specific distance, pressure and time was the only surface treatment in DT Light Post and Transluma Post that increased the bond strength to dual cure resin composite cores. FRC Postec Plus post did not shown an increase in bond strength in any group.     

Comparing the effectiveness of self-curing and light curing in polymerization of dual-cured core buildup materials

BackgroundThe authors conducted an in vitro study to investigate the influence of various curing protocols on subsurface microhardness of dual-cured resin-based composites.MethodsThe authors filled molds with four dual-cured resin-based composite core buildup materials: Clearfil DC Core Automix (Kuraray, Tokyo), Core?X flow (Dentsply DeTrey, Konstanz, Germany), LuxaCore Z-Dual (DMG, Hamburg, Germany) and MultiCore Flow (Ivoclar Vivadent, Schaan, Liechtenstein). They light cured the specimens for 20 or 60 seconds immediately after the filling procedure (time delay, 0 seconds) or after a 90-or 300-second delay. Self-cured specimens served as controls. The authors tested 15 specimens in each group. They measured the Knoop hardness number (KHN) at depths of 0.25, 2.00 and 5.50 millimeters two weeks after the initiation of polymerization.ResultsLight curing with Core?X flow, LuxaCore Z-Dual and MultiCore Flow did not result in significantly higher KHNs at any depth compared with those for the self-cured control specimens. For Clearfil DC Core Automix, immediate light curing for 60 seconds resulted in significantly higher KHNs than those for self-cured specimens only at a depth of 5.50 mm (P = .0171). The study results showed no significant differences in KHN at different depths for Core?X flow specimens, independent of the curing protocol. All other materials exhibited a significant decrease in KHN at increased depths in only one of the six light-cured groups.ConclusionThe results of this study show that photoactivation of the tested dual-cured materials provided no clinically relevant benefit compared with self-curing with regard to the degree of microhardness.Clinical ImplicationsThe dominant self-curing mode allows placement of the tested buildup materials in areas inaccessible to a curing light.     

Dentin bond strengths of three adhesive/composite core systems using different curing units

This study evaluated the tensile bond strengths of three adhesive/composite core materials to bovine dentin using three different curing units. Bovine dentin surfaces were ground with 600-grit SiC paper. Bonding area was demarcated with a vinyl tape (4-mm-diameter hole). Three adhesive/composite core systems--S6054 (experimental), UniFil Core, and Clearfil DC Core Automix--were used with three curing units--Curing Light XL3000 (quartz-tungsten-halogen), Hyper Lightel (high-power quartz-tungsten-halogen), and LEDemetronl (blue light-emitting diode)--according to manufacturers' instructions. After 24 hours of storage in water at 37 degrees C, tensile bond strengths were measured at a crosshead speed of 2 mm/min. Results were statistically analyzed with one-way ANOVA and Tukey's HSD test (p < 0.05). Highest tensile bond strength was obtained using Clearfil DC Core Automix with Hyper Lightel.     

Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

Objective

The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement.

Material and Methods

Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO₂ particles, silane application; (AO) Sandblasting with 50 mm Al₂O₃ particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05).

Results

The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling.

Conclusion

Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement.     

Effects of tooth surface treatment with the acid solutions containing metal chloride on the bond strength of a self-curing resin

We evaluated the use of aqueous solutions containing an acid and metal chloride as a tooth surface pretreating agent. Nineteen solutions containing 10% acetic (AA), citric (CA), lactic (LA) or phosphoric acid (PA) and/or 0.11 M aluminum (Al), cupric (Cu) or ferric chloride (Fe) were prepared. The tensile bond strengths of the TBB-O initiated MENTA resin to tooth surfaces treated with the respective aqueous solutions were measured. The amount of dissolved Ca by each of the solutions was determined. The demineralization of tooth surface was mainly dependent on the pH of the aqueous solutions. There was no specific relationship between the bond strength and amount of dissolved Ca. This suggests that a high bond strength can be obtained without serious demineralization. Pretreatment with the CA-Cu, CA-Fe or LA-Cu solution markedly enhanced the bond strengths to both enamel and dentin, although these solutions demineralized tooth surface less than the solutions containing 10% PA.     

Effect of three endodontic materials on the bond strength of two composite core materials to dentin

PURPOSE: This study investigated the effect of dentin treatment with iodine potassium iodide, calcium hydroxide or a biphenol-A- diglycidylether epoxy resin sealer on the dentin bond strength of titanium-reinforced Bis-GMA and urethane dimethacrylate composite materials. MATERIALS AND METHODS: Dentin was exposed in four groups of extracted teeth (20 specimens each). Three groups were treated with one of the contaminants and the fourth group was left uncovered and served as the control group. All specimens were stored for 1 week at 37 degrees C and 100% humidity. The dentin surfaces were cleaned with pumice slurry using a prophylaxis rubber cup, rinsed and dried. Then the dentin surfaces were treated using the conditioner and the primer of the GLUMA adhesive system followed by placement of composite core materials. After 20 minutes, debonding of the core materials was accomplished using a shear-peel test. A two-way analysis of variance and Tukey's multiple range test was performed based upon core type and contaminant type (alpha = 0.05). RESULTS: Titanium-reinforced Bis-GMA composite showed significantly greater bond strength values than the urethane dimethacrylate composite material (p < 0.0001). The mean bond strength values in megapascals for the Bis-GMA resin ranged from 8.47 +/-1.52 for the calcium hydroxide group to 9.81 +/-0.94 for the control group. Mean bond strengths for the urethane dimethacrylate resin ranged from 3.35 +/-0.90 for calcium hydroxide to 3.99 +/-0.88 for iodine potassium iodide groups. Within each core group, no difference in bond strengths were noted compared to the uncontaminated control. CONCLUSION: Pretreatment of the dentin with iodine potassium iodide, calcium hydroxide, or epoxy resin followed by pumicing and using the GLUMA system conditioner and primer had no effect on the bond strength of the two resin composite core materials. However, the titanium reinforced Bis-GMA composite exhibited significantly greater bond strength to dentin than the urethane dimethacrylate based composite.     

Effects of high-speed curing devices on shear bond strength and microleakage of orthodontic brackets.

This study evaluated the shear-peel bond strength and mode of bond failure of 3 curing devices (plasma arc light, argon laser, and conventional halogen light) and 2 orthodontic bracket adhesives with different filler contents (Transbond XT and Adhesive Precoated [APC]). Observations of microleakage were also reported. Ninety human adolescent premolars were randomly divided into 6 groups, and standardized brackets were bonded according to the manufacturers' recommendations. The plasma arc light produced significantly (P =.006) higher bond strength than did the halogen light or the argon laser when Transbond was used. When APC was used, the plasma arc light and the halogen light produced similar results, and they both produced significantly (P =.015) higher bond strengths than did the argon laser. Overall, the APC showed substantially less variation in bond strength than did the Transbond. Although all curing methods showed significant microleakage (P <.001), differences among the 3 curing lights occurred only when APC was used. Microscopic evaluations demonstrated that 95% of the specimens failed for adhesion at the bracket or tooth surface; the argon laser produced the highest adhesive remnant index scores. On the basis of bond strength and microleakage results, the plasma arc light was comparable with or superior to the other curing devices, depending on the adhesive used.