This year,Toray Industries,Inc.,announced that it has developed an insulating resin material for hybrid bonding(micro bonding).The material is based on Semicofine™and Photoneece™.These are high-heat-resistant polyimid...This year,Toray Industries,Inc.,announced that it has developed an insulating resin material for hybrid bonding(micro bonding).The material is based on Semicofine™and Photoneece™.These are high-heat-resistant polyimide coatings for semiconductor and display devices.The new material combines a conventional polyimide coating agent with the company’s processing and bonding technologies.It can enhance the yields and reliability of semiconductor devices in the hybrid bonding process,which entails bonding semiconductor chips with metal electrodes.Toray will push ahead with prototyping and providing samples to customers.It aims to obtain materials certification in 2025 and start mass production by 2028.展开更多
Bonded NdFeB magnets were prepared by compression molding. The effect of preparation technology on their magnetic and mechanical properties was studied through the analysis of density, Br, Hcj, （BH）max, bending stre...Bonded NdFeB magnets were prepared by compression molding. The effect of preparation technology on their magnetic and mechanical properties was studied through the analysis of density, Br, Hcj, （BH）max, bending strength, and compressive strength of the bonded magnets. The results showed that the magnetic properties decreased with increasing binder content, whereas the mechanical properties increased. Br and （BH）max increased with rising pressure, whereas Hcj decreased. For a fixed mass fraction of the binder, the optimal pressure was 620 MPa and the best thermosetting temperature was 160°C. These conditions made the bonded magnets have the optimal mechanical properties. Scanning electron microscopy （SEM） analyses of the fracture surfaces indicated that the epoxy resin bonded magnets exhibited brittle behavior.展开更多
Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly di...Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each.In group 1,each tooth was hemisected into two halves.One half was assigned to control subgroup 1,which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing.In group 2,the teeth were also hemisected into two halves.One half was assigned to control subgroup 2,which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer.Microtensile bond strength was immediately tested after specimen preparation.Results When the adhesive was applied three times before light curing,the bond strength of the experimental subgroup 1(n=33,57.49±11.61 MPa) was higher than that of the control subgroup 1(n=31,49.71±11.43 MPa,P<0.05).When using the technique of applying multiple layers of adhesive with light curing each successive layer,no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2(P>0.05).Conclusion Multiple coatings of one-step self-etching adhesive can increase the immediate bond strength to primary dentin when using the technique of light-curing after applying three layers of adhesive.展开更多
Objective To investigate whether multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin. Methods Twelve caries-free human primary molars were randomly divided into 2 gro...Objective To investigate whether multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin. Methods Twelve caries-free human primary molars were randomly divided into 2 groups. In group 1, each tooth was hemisected into 2 halves. One half was assigned to the control subgroup 1, which was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instruc- tions; the other half was assigned to experimental subgroup 1, in which the adhesive was applied three times before light curing. In group 2, one split half tooth was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instructions; for the other half, three layers of adhesive were applied with each successive layer of light curing. Specimens were stored in 0.9% NaC1 containing 0.02% sodium azide at 37℃ for 18 months and then were subjected to microtensile bond strength test and the fracture mode analysis. Results When the adhesive was applied three times before light curing, the bond strength of the ex- perimental subgroup 1 was significantly higher than that of the control subgroup 1 （47.46__＋13.91 vs. 38.12＋11.21 MPa, P〈O.05）. When using the technique of applying multiple layers of adhesive with each successive layer of light curing, no difference was observed in bond strength between the control subgroup and the experimental subgroup （39.40＋8.87 vs. 40.87-＋9.33 MPa, P〉O.05）. Conclusion Multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin when using the technique of light-curing after applying 3 layers of adhesive.展开更多
To evaluate the shear bond strength（SBS） and bond failure interface after the debonding of orthodontic brackets with a resin-modified glass ionomer cement（RMGIC） under six bonding conditions, 140 premolar teeth we...To evaluate the shear bond strength（SBS） and bond failure interface after the debonding of orthodontic brackets with a resin-modified glass ionomer cement（RMGIC） under six bonding conditions, 140 premolar teeth were randomly divided into seven groups. The brackets of all groups, except for control group, were bonded using a RMGIC. The teeth were debonded using a universal testing machine. The shear bond strength, adhesive remnant index （ARI） and enamel fracture were examined for each debonding. A significant difference existed in SBS under wet and dry conditions in two groups of Fuji Ortho LC. Different degree of enamel fracture was seen in groups of Fuji Ortho LC（dry/37% phosphoric acid treated） after debonding. Bond failed predominantly at the enamel-adhesive interface, except for phosphoric acid treated groups. The RMGIC achieve a clinically effective adhesion in orthodontics under different bonding conditions.展开更多
Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconi...Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated： Maxcem （MA）, Smartcem （SM）, Rely X Unicem Aplicap （UN）, Breeze （BR）, Biscem （BI）, Set （SE）, and Clearfil SA luting （CL）. The specimens were grouped according to conditioning as follows： Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 μm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating ＋ silanization. Specimens were stored in distilled water at 37℃ for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, B1, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP- containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.展开更多
The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups accord...The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups according to 4 different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M). The shear bond strength was determined in the first 30 min after bonding. The analysis of variance indicated that the shear bond strengths of the 4 groups were significantly different (F=11.89, P<0.05). Tukey HSD tests indicated that contamination both before and after the application of the acid-etch primer resulted in a significantly lower (=4.6±1.7 MPa) shear bond strength than either the control group (=8.8±1.9 MPa) or the groups where contamination occurred either before (=7.9±2.0 MPa) or after (=6.9±1.5 MPa) the application of the primer. It was concluded that the new acid-etch primer could maintain adequate shear bond strength if contamination occurred either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer could significantly reduce the shear bond strength of orthodontic brackets.展开更多
We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars...We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin （1 mm below the dentine-enamel junction）, deep dentin （1 mm above the highest pulp horn） and cervical dentin （0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction）. Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mrn/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin （P 〈 0.001）. Micro-ten- sile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions （P 〈 0.001）. Immediate ＂micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements （P 〈 0.001）. It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.展开更多
This study presents a simple technique for strengthening the adhesive-bond strength between aluminium(Al)substrate and carbon fibre reinforced polymer(CFRP) utilising resin pre-coating(RPC) with carbon nanotubes(CNTs)...This study presents a simple technique for strengthening the adhesive-bond strength between aluminium(Al)substrate and carbon fibre reinforced polymer(CFRP) utilising resin pre-coating(RPC) with carbon nanotubes(CNTs). The CNT-containing RPC solution with 90 wt% acetone and 10 wt% resin(without hardener) was applied onto Al substrates, where micro-/nano-vertical channels had been created by chemical or mechanical surface treatments to accommodate CNTs. RPC was able to fill all micro-/nano-cavities over the Al substrate surface, then CNTs were pulled into those vertical micro-channels by the capillary action generated from acetone evaporation.Normal epoxy adhesive(resin + hardener) was applied after the CNT-containing RPC treatment. CNTs bridging across the interface between the adhesive joint and Al substrate and sealing of micro-/nano-cavities by RPC effectively enhanced the interfacial shear bond strength between the Al substrate and CFRP by 30–100%depending on the Al substrate surface profiles. Al substrates with two different chemical treatments were compared in this study for the effectiveness of CNT interfacial reinforcement. Results from a steel substrate after sandblasting were also included for comparison.展开更多
The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 ...The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 and 20°C/min) and the bonding property was evaluated by the wet shear strength and wood failure of two-ply plywood panels after soaking in water (48 hours at room temperature and followed by 1-hour boiling). The test results indicated that the NCC content had little influence on the peak temperature, activation energy and the total heat of reaction of LPF resin at 5 and 10°C/min. But at 20°C/min, LPF0.00% (LPF resin without NCC) showed the highest total heat of reaction, while LPF0.25% (LPF resin containing 0.25% NCC content) and LPF0.50% (LPF resin containing 0.50% NCC content) gave the lowest value. The wet shear strength was affected by the NCC content to a certain extent. With regard to the results of one-way analysis of variance, the bonding quality could be improved by NCC and the optimum NCC content ranged from 0.25% to 0.50%. The wood failure was also affected by the NCC content, but the trend with respect to NCC content was not clear.展开更多
The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements.Eight square-shaped（φ12 mm×5 mm high） Y-TZP cer...The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements.Eight square-shaped（φ12 mm×5 mm high） Y-TZP ceramic were studied blocks（LAVATM,3M ESPE,USA） and flat occlusal dentin blocks were fabricated,pre-treated（airborne abrasion with 125μm Al2O3 particles,tribochemical silica coating with 110 μm Al2O3 particles modified by silica oxide）,and bonded to each other using resin cements（Panavia F 2.0,RelyX Unicem）.Thereafter the trilayer specimens were cut into microbar specimens with a bonding area of approximately 1.0±0.1 mm2 and then microtensile bond strength tests were performed.The Y-TZP ceramic following airborne particle abrasion with 125μm Al2O3 and silicoating,the surface roughness of Y-TZP and its surface silica content were confirmed to increase.Overall,the Y-TZP ceramic surface treatment with a tribochemical silica coating showed the highest microtensile bond strength of the phosphate monomer-based resin cement to Y-TZP ceramic（mean MPa=18.11±0.27（Panavia F 2.0）,17.45±0.39（Rely X Unicem）.In cases in which a silica coating was applied,there was no significant difference in the bonding strength depending on resin cements（P0.05）.展开更多
Background: Chlorhexidine could have effect on shear bond strength of composite resin-dentin. Objective: The purpose of this study is to compare two methods of chlorhexidine application of shear bond strength degradat...Background: Chlorhexidine could have effect on shear bond strength of composite resin-dentin. Objective: The purpose of this study is to compare two methods of chlorhexidine application of shear bond strength degradation between composite resin and dentin. Methods: Thirty samples of dentin were taken from the crown of premolars and then divided into three groups (n = 10). Group 1 were applied bonding without chlorhexidine, group 2 were applied with liquid chlorhexidine and followed by bonding, group 3 were applied bonding which contains chlorhexidine. Each group was divided into two sub-groups (n = 5): the group with and without 10% NaOCl immersion for one hour. Then, 4 samples in each sub-group were used to measure shear bond strength using Universal Testing Machine, and 1 sample was examined with Scanning Electron Microscope (SEM). Data were analyzed using SPSS 17 by Mann-Whitney and Kruskal Wallis test. Results: The highest mean shear bond strength without 10% NaOCl immersion was in group 1, while the highest mean with 10% NaOCl immersion was in group 3. Significant differences occurred between the groups 1 and 2, groups 2 and 3. Conclusion: Method of using bonding contains chlorhexidine can increase and inhibit degradation shear bond strength between composite resin and dentin.展开更多
This study aimed to evaluate the effects of universal primers on the tensile bond strength between zirconia and resin composites.Zirconia specimens were divided into five groups based on the surface treatment with the...This study aimed to evaluate the effects of universal primers on the tensile bond strength between zirconia and resin composites.Zirconia specimens were divided into five groups based on the surface treatment with the following primers:MP(Monobond Plus),SU(ScotchBond Universal),AZ(AZ Primer),BM(Beauty bond Multi),and BL(Bondmer Lightless).After priming,stainless steel rods were bonded to the zirconia specimens with composite resin.The tensile bond strength test was performed:stored at room temperature for 1 day;stored in distilled water at 37°C for 7 days;and underwent thermal cycling.The BL group demonstrated a significantly higher tensile bond strength than other groups when stored at room temperature for 1 day(p<0.05).The primer that acted via chemical polymerization appeared to be most effective in improving the bond strength between the two materials in this study.展开更多
Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with s...Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with sixty polystyrene-supported quaternary ammonium salt catalysts was synthesized. The reduction of acetophenone by NaBH, was used as the probing reaction to select out the most active catalyst in the library by using iterative method, which was the gel-type triethanolamine aminating strongly basic anion exchange resin with the crosslinking degree of 2% A hydrogen bonding assisted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.展开更多
The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on ino...The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on inorganic binder-bonded sands no matter the test items or the atmospheric protection, while the instrumentss specially designed for resin-bonded sand are not yet available. A new instrument for testing the hightemperature performance of resin sand was designed including the confirmation of the testing parameters, loading, measurement and control systems, and the design of the frame shape and heating furnace. This instrument can test the compressive strength, heat tolerance time and restraining load of phenol-formaldehyde resin coated sand, self-hardened furan resin sand, and trimethylamine(TEA)-based resin bonded sand at high temperatures. The developed instrument has a high accuracy offering smaller than 0.3% deviation at a full scale in the measurement of the high temperature compressive strength and the restraining load over the range of 0-6.8 MPa and 0-2,000 N, respectively. The high temperature heat tolerance time range is 0-300 s and its measurement accuracy is ±1 s.展开更多
目的:探讨通用型粘结剂(Single Bond Universal,SBU)对牙本质的粘结强度。方法:选取A组(SBU)、B组(S3bond)和C组(hybrid coat,Hy C)三组不同类型处理剂,分别比较A组与B、C两组的牙本质微拉伸粘结强度。各组样本数量相同(n=30),结果通过...目的:探讨通用型粘结剂(Single Bond Universal,SBU)对牙本质的粘结强度。方法:选取A组(SBU)、B组(S3bond)和C组(hybrid coat,Hy C)三组不同类型处理剂,分别比较A组与B、C两组的牙本质微拉伸粘结强度。各组样本数量相同(n=30),结果通过两独立样本t检验进行统计学分析(α=0.05),通过扫描电镜观察断裂模式。结果:A组拉伸强度约23.371MP,与B组间无统计学差异,显示了与B组同等的粘结强度;与C组(17.314MP)比较,A组显示了较高的粘结强度,两组间有显著的统计学差异。断裂模式显示,三组断裂都主要以界面断裂为主,A、B两组样本断面可见牙本质小管结构,C组可见极少量牙本质小管结构。结论:通用型粘结剂Single Bond Universal具备与传统自酸一步法粘结剂同等的粘结强度,可以满足临床粘结要求;Single Bond Universal作为牙本质保护膜用于即刻牙本质封闭时,对牙本质小管有一定的封闭作用,并且可以获得较hybrid coat牙本质保护膜更高的粘结力,但其对牙本质小管的封闭效果还有待进一步实验研究。展开更多
文摘This year,Toray Industries,Inc.,announced that it has developed an insulating resin material for hybrid bonding(micro bonding).The material is based on Semicofine™and Photoneece™.These are high-heat-resistant polyimide coatings for semiconductor and display devices.The new material combines a conventional polyimide coating agent with the company’s processing and bonding technologies.It can enhance the yields and reliability of semiconductor devices in the hybrid bonding process,which entails bonding semiconductor chips with metal electrodes.Toray will push ahead with prototyping and providing samples to customers.It aims to obtain materials certification in 2025 and start mass production by 2028.
基金supported by the National Natural Science Foundation of China (No. 50074014)the Science Foundation of Hubei Province,China (No. 2003ABA092)
文摘Bonded NdFeB magnets were prepared by compression molding. The effect of preparation technology on their magnetic and mechanical properties was studied through the analysis of density, Br, Hcj, （BH）max, bending strength, and compressive strength of the bonded magnets. The results showed that the magnetic properties decreased with increasing binder content, whereas the mechanical properties increased. Br and （BH）max increased with rising pressure, whereas Hcj decreased. For a fixed mass fraction of the binder, the optimal pressure was 620 MPa and the best thermosetting temperature was 160°C. These conditions made the bonded magnets have the optimal mechanical properties. Scanning electron microscopy （SEM） analyses of the fracture surfaces indicated that the epoxy resin bonded magnets exhibited brittle behavior.
文摘Objective To investigate the effect of multiple coatings of the one-step self-etching adhesive on immediate microtensile bond strength to primary dentin.Methods Twelve caries-free human primary molars were randomly divided into 2 groups with 6 teeth each.In group 1,each tooth was hemisected into two halves.One half was assigned to control subgroup 1,which was bonded with a single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 1 in which the adhesive was applied three times before light curing.In group 2,the teeth were also hemisected into two halves.One half was assigned to control subgroup 2,which was bonded with the single-step self-etching adhesive according to the manufacturer's instructions;the other half was assigned to experimental subgroup 2 in which three layers of adhesive were applied with light curing each successive layer.Microtensile bond strength was immediately tested after specimen preparation.Results When the adhesive was applied three times before light curing,the bond strength of the experimental subgroup 1(n=33,57.49±11.61 MPa) was higher than that of the control subgroup 1(n=31,49.71±11.43 MPa,P<0.05).When using the technique of applying multiple layers of adhesive with light curing each successive layer,no difference of immediate bond strength was observed between the control subgroup 2 and the experimental subgroup 2(P>0.05).Conclusion Multiple coatings of one-step self-etching adhesive can increase the immediate bond strength to primary dentin when using the technique of light-curing after applying three layers of adhesive.
文摘Objective To investigate whether multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin. Methods Twelve caries-free human primary molars were randomly divided into 2 groups. In group 1, each tooth was hemisected into 2 halves. One half was assigned to the control subgroup 1, which was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instruc- tions; the other half was assigned to experimental subgroup 1, in which the adhesive was applied three times before light curing. In group 2, one split half tooth was bonded with a commercially available one-step self-etching adhesive according to the manufacturer＇s instructions; for the other half, three layers of adhesive were applied with each successive layer of light curing. Specimens were stored in 0.9% NaC1 containing 0.02% sodium azide at 37℃ for 18 months and then were subjected to microtensile bond strength test and the fracture mode analysis. Results When the adhesive was applied three times before light curing, the bond strength of the ex- perimental subgroup 1 was significantly higher than that of the control subgroup 1 （47.46__＋13.91 vs. 38.12＋11.21 MPa, P〈O.05）. When using the technique of applying multiple layers of adhesive with each successive layer of light curing, no difference was observed in bond strength between the control subgroup and the experimental subgroup （39.40＋8.87 vs. 40.87-＋9.33 MPa, P〉O.05）. Conclusion Multiple coatings can improve the bond durability of one-step self-etching adhesive to primary dentin when using the technique of light-curing after applying 3 layers of adhesive.
文摘To evaluate the shear bond strength（SBS） and bond failure interface after the debonding of orthodontic brackets with a resin-modified glass ionomer cement（RMGIC） under six bonding conditions, 140 premolar teeth were randomly divided into seven groups. The brackets of all groups, except for control group, were bonded using a RMGIC. The teeth were debonded using a universal testing machine. The shear bond strength, adhesive remnant index （ARI） and enamel fracture were examined for each debonding. A significant difference existed in SBS under wet and dry conditions in two groups of Fuji Ortho LC. Different degree of enamel fracture was seen in groups of Fuji Ortho LC（dry/37% phosphoric acid treated） after debonding. Bond failed predominantly at the enamel-adhesive interface, except for phosphoric acid treated groups. The RMGIC achieve a clinically effective adhesion in orthodontics under different bonding conditions.
文摘Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated： Maxcem （MA）, Smartcem （SM）, Rely X Unicem Aplicap （UN）, Breeze （BR）, Biscem （BI）, Set （SE）, and Clearfil SA luting （CL）. The specimens were grouped according to conditioning as follows： Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 μm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating ＋ silanization. Specimens were stored in distilled water at 37℃ for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, B1, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP- containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.
文摘The effect of saliva contamination on the shear bond strength of orthodontic brackets, at various stages of the bonding procedure using a new self-etch primer was studied. The samples were divided into 4 groups according to 4 different enamel surface conditions: Group A: dry; Group B: saliva contamination before priming; Group C: saliva contamination after priming, and Group D: saliva contamination before and after priming. Stainless steel brackets were bonded in each test group with a light-cured composite resin (TransbondXT 3M). The shear bond strength was determined in the first 30 min after bonding. The analysis of variance indicated that the shear bond strengths of the 4 groups were significantly different (F=11.89, P<0.05). Tukey HSD tests indicated that contamination both before and after the application of the acid-etch primer resulted in a significantly lower (=4.6±1.7 MPa) shear bond strength than either the control group (=8.8±1.9 MPa) or the groups where contamination occurred either before (=7.9±2.0 MPa) or after (=6.9±1.5 MPa) the application of the primer. It was concluded that the new acid-etch primer could maintain adequate shear bond strength if contamination occurred either before or after the application of the primer. On the other hand, contamination both before and after the application of the primer could significantly reduce the shear bond strength of orthodontic brackets.
文摘We sought to evaluate immediate and delayed micro-tensile bond strength of Panavia F2.0 and Multilink Sprint resin cement to superficial, deep and cervical dentin. Thirty-six freshly extracted non-carious human molars were sectioned in the mesiodistal direction to expose three different dentin regions including superficial dentin （1 mm below the dentine-enamel junction）, deep dentin （1 mm above the highest pulp horn） and cervical dentin （0.5 mm above the cemento-enamel junction and 0.5 mm below the dentine-enamel junction）. Resin cements were applied on dentin surfaces and composite blocks were luted under constant seating pressure. Each group was divided into three subgroups according to time intervals. Specimens were sectioned to obtain sticks of 1 mm2 in diameter and subjected to microtensile bond strength testing at a cross head speed of 1 mrn/min. Both resin cements showed higher micro-tensile bond strength to superficial dentin than that to deep or cervical dentin （P 〈 0.001）. Micro-ten- sile bond strengths of Panavia F2.0 were higher than those of Multilink Sprint at different dentin regions （P 〈 0.001）. Immediate ＂micro-tensile bond strengths were higher than those of delayed micro-tensile bond strengths for both resin cements （P 〈 0.001）. It was concluded that resin cements with different chemical formulations and applications yield significantly different micro-tensile bond strengths to different dentin regions.
基金Chang’an University of China for a visiting professor grant (2018-2020) for research collaboration between Chang’an University and University of Western Australia。
文摘This study presents a simple technique for strengthening the adhesive-bond strength between aluminium(Al)substrate and carbon fibre reinforced polymer(CFRP) utilising resin pre-coating(RPC) with carbon nanotubes(CNTs). The CNT-containing RPC solution with 90 wt% acetone and 10 wt% resin(without hardener) was applied onto Al substrates, where micro-/nano-vertical channels had been created by chemical or mechanical surface treatments to accommodate CNTs. RPC was able to fill all micro-/nano-cavities over the Al substrate surface, then CNTs were pulled into those vertical micro-channels by the capillary action generated from acetone evaporation.Normal epoxy adhesive(resin + hardener) was applied after the CNT-containing RPC treatment. CNTs bridging across the interface between the adhesive joint and Al substrate and sealing of micro-/nano-cavities by RPC effectively enhanced the interfacial shear bond strength between the Al substrate and CFRP by 30–100%depending on the Al substrate surface profiles. Al substrates with two different chemical treatments were compared in this study for the effectiveness of CNT interfacial reinforcement. Results from a steel substrate after sandblasting were also included for comparison.
文摘The curing behavior of lignin-based phenol-formaldehyde (LPF) resin with different contents of nano-crystalline cellulose (NCC) was studied by differential scanning calorimetry (DSC) at different heating rates (5, 10 and 20°C/min) and the bonding property was evaluated by the wet shear strength and wood failure of two-ply plywood panels after soaking in water (48 hours at room temperature and followed by 1-hour boiling). The test results indicated that the NCC content had little influence on the peak temperature, activation energy and the total heat of reaction of LPF resin at 5 and 10°C/min. But at 20°C/min, LPF0.00% (LPF resin without NCC) showed the highest total heat of reaction, while LPF0.25% (LPF resin containing 0.25% NCC content) and LPF0.50% (LPF resin containing 0.50% NCC content) gave the lowest value. The wet shear strength was affected by the NCC content to a certain extent. With regard to the results of one-way analysis of variance, the bonding quality could be improved by NCC and the optimum NCC content ranged from 0.25% to 0.50%. The wood failure was also affected by the NCC content, but the trend with respect to NCC content was not clear.
文摘The effects of surface conditioning methods on the microtensile bond strength of Y-TZP ceramic were studied based on airborne particle abrasion and resin cements.Eight square-shaped（φ12 mm×5 mm high） Y-TZP ceramic were studied blocks（LAVATM,3M ESPE,USA） and flat occlusal dentin blocks were fabricated,pre-treated（airborne abrasion with 125μm Al2O3 particles,tribochemical silica coating with 110 μm Al2O3 particles modified by silica oxide）,and bonded to each other using resin cements（Panavia F 2.0,RelyX Unicem）.Thereafter the trilayer specimens were cut into microbar specimens with a bonding area of approximately 1.0±0.1 mm2 and then microtensile bond strength tests were performed.The Y-TZP ceramic following airborne particle abrasion with 125μm Al2O3 and silicoating,the surface roughness of Y-TZP and its surface silica content were confirmed to increase.Overall,the Y-TZP ceramic surface treatment with a tribochemical silica coating showed the highest microtensile bond strength of the phosphate monomer-based resin cement to Y-TZP ceramic（mean MPa=18.11±0.27（Panavia F 2.0）,17.45±0.39（Rely X Unicem）.In cases in which a silica coating was applied,there was no significant difference in the bonding strength depending on resin cements（P0.05）.
文摘Background: Chlorhexidine could have effect on shear bond strength of composite resin-dentin. Objective: The purpose of this study is to compare two methods of chlorhexidine application of shear bond strength degradation between composite resin and dentin. Methods: Thirty samples of dentin were taken from the crown of premolars and then divided into three groups (n = 10). Group 1 were applied bonding without chlorhexidine, group 2 were applied with liquid chlorhexidine and followed by bonding, group 3 were applied bonding which contains chlorhexidine. Each group was divided into two sub-groups (n = 5): the group with and without 10% NaOCl immersion for one hour. Then, 4 samples in each sub-group were used to measure shear bond strength using Universal Testing Machine, and 1 sample was examined with Scanning Electron Microscope (SEM). Data were analyzed using SPSS 17 by Mann-Whitney and Kruskal Wallis test. Results: The highest mean shear bond strength without 10% NaOCl immersion was in group 1, while the highest mean with 10% NaOCl immersion was in group 3. Significant differences occurred between the groups 1 and 2, groups 2 and 3. Conclusion: Method of using bonding contains chlorhexidine can increase and inhibit degradation shear bond strength between composite resin and dentin.
文摘This study aimed to evaluate the effects of universal primers on the tensile bond strength between zirconia and resin composites.Zirconia specimens were divided into five groups based on the surface treatment with the following primers:MP(Monobond Plus),SU(ScotchBond Universal),AZ(AZ Primer),BM(Beauty bond Multi),and BL(Bondmer Lightless).After priming,stainless steel rods were bonded to the zirconia specimens with composite resin.The tensile bond strength test was performed:stored at room temperature for 1 day;stored in distilled water at 37°C for 7 days;and underwent thermal cycling.The BL group demonstrated a significantly higher tensile bond strength than other groups when stored at room temperature for 1 day(p<0.05).The primer that acted via chemical polymerization appeared to be most effective in improving the bond strength between the two materials in this study.
基金Supported by the National Natural Science Foundation of China !(Grant No. 29574164 and 29974015)
文摘Possibilities for enhancement of catalytic reaction rate by combining phase transfer catalysis and hydrogen bonding of the catalyst with the substrate and reagent were studied. A phase transfer catalyst library with sixty polystyrene-supported quaternary ammonium salt catalysts was synthesized. The reduction of acetophenone by NaBH, was used as the probing reaction to select out the most active catalyst in the library by using iterative method, which was the gel-type triethanolamine aminating strongly basic anion exchange resin with the crosslinking degree of 2% A hydrogen bonding assisted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.
文摘The mechanical properties of resin-bonded sand mixtures at high temperatures significantly affect the quality of casting. However, the existing instruments for high-temperature performances testing mainly focus on inorganic binder-bonded sands no matter the test items or the atmospheric protection, while the instrumentss specially designed for resin-bonded sand are not yet available. A new instrument for testing the hightemperature performance of resin sand was designed including the confirmation of the testing parameters, loading, measurement and control systems, and the design of the frame shape and heating furnace. This instrument can test the compressive strength, heat tolerance time and restraining load of phenol-formaldehyde resin coated sand, self-hardened furan resin sand, and trimethylamine(TEA)-based resin bonded sand at high temperatures. The developed instrument has a high accuracy offering smaller than 0.3% deviation at a full scale in the measurement of the high temperature compressive strength and the restraining load over the range of 0-6.8 MPa and 0-2,000 N, respectively. The high temperature heat tolerance time range is 0-300 s and its measurement accuracy is ±1 s.
文摘目的:探讨通用型粘结剂(Single Bond Universal,SBU)对牙本质的粘结强度。方法:选取A组(SBU)、B组(S3bond)和C组(hybrid coat,Hy C)三组不同类型处理剂,分别比较A组与B、C两组的牙本质微拉伸粘结强度。各组样本数量相同(n=30),结果通过两独立样本t检验进行统计学分析(α=0.05),通过扫描电镜观察断裂模式。结果:A组拉伸强度约23.371MP,与B组间无统计学差异,显示了与B组同等的粘结强度;与C组(17.314MP)比较,A组显示了较高的粘结强度,两组间有显著的统计学差异。断裂模式显示,三组断裂都主要以界面断裂为主,A、B两组样本断面可见牙本质小管结构,C组可见极少量牙本质小管结构。结论:通用型粘结剂Single Bond Universal具备与传统自酸一步法粘结剂同等的粘结强度,可以满足临床粘结要求;Single Bond Universal作为牙本质保护膜用于即刻牙本质封闭时,对牙本质小管有一定的封闭作用,并且可以获得较hybrid coat牙本质保护膜更高的粘结力,但其对牙本质小管的封闭效果还有待进一步实验研究。
