Effects of sodium hypochlorite gel and sodium hypochlorite solution on dentin bond strength

The aim of this study was to determine the effect of 10% NaOCl gel and 10% NaOCl solution on dentin bond strengths of four adhesive systems. One hundred eighty bovine incisors were ground to achieve a flat polished surface, then divided into 12 groups: Gluma One Bond [G1-control; G2-NaOCl solution; G3-NaOCl gel]; Prime & Bond 2.1 [G4-control; G5-NaOCl solution; G6-NaOCl gel]; Single Bond [G7-control; G8-NaOCl solution; G9-NaOCl gel]; Prime & Bond NT [G10-control; G11-NaOCl solution; G12-NaOCl gel]. Dentin was etched, rinsed, and blot dried. For the experimental groups, after acid etching, 10% NaOCl solution or 10% NaOCl gel was applied for 60 s, rinsed, and blot dried. Composite resin was inserted and light cured. Shear bond strengths were tested with a crosshead speed of 0.5 mm/min. The mean values MPa (SD) were analyzed with two-way ANOVA and Tukey's tests (alpha < 0.01). Ten percent NaOCl solution significantly increased Gluma One Bond strength. No effect was observed for the other adhesives. The 10% NaOCl gel did not affect bond strengths. Ten percent NaOCl gel was less effective on collagen removal as compared to 10% NaOCl solution. The influence of collagen removal on bond strength is dependent on adhesive system, where both the solvent and the monomer can influence the results.     

Liquid photocurable biodegradable copolymers: in vivo degradation of photocured poly(epsilon-caprolactone-co-trimethylene carbonate)

The present investigation was designed to test cellular toxicity of modern dentin adhesives. With the use of the products Ariston Liner, Etch & Prime 3.0, Optibond Solo, Prime & Bond NT, Scotchbond 1, and Syntac Sprint, test specimens were prepared according to the manufacturers' instructions and transferred into a culture medium. Eluates were obtained and pipetted onto fibroblast cultures, incubated, and subsequently stained. The respective cell densities and the numbers of normal, altered, and dead cells were determined and compared with control cell cultures. Statistical analysis of the data showed that all materials caused cytotoxic effects. Scotchbond 1 displayed the highest number of dead cells. The difference was statistically significant compared to Etch" 3.0, Optibond Solo, Prime&Bond NT, and the control. The lowest cell density was found for Scotchbond 1 and Ariston Liner. The difference was also statistically significant in comparison with Etch" 3.0, Optibond Solo, Prime&Bond NT, and the control. To conclude, all tested dentin adhesives caused cytotoxic reactions. Taking the limitations of an in vitro experiment into consideration, Prime&Bond NT, Optibond Solo, and Etch" 3.0 appear to be the most recommendable products, and Scotchbond 1 and Ariston Liner the least.     

Evaluation of the fatigue behavior of the resin-dentin bond with the use of different methods

The clinical performance of directly bonded resin composites is fundamentally dependent on durable adhesion to prevent gap formation over time. The goal of this investigation was to evaluate the effectiveness of various dentin adhesives by means of quasistatic and dynamic dentin bond strengths, and also to determine marginal and internal gap formation after loading in an artificial oral environment. Three hundred thirty human third molars were used within four weeks of extraction. Adhesives used were A.R.T. Bond, OptiBond FL, Scotchbond Multi-Purpose Plus, Single Bond, Prime & Bond NT, and One Up Bond F for bonding of one resin composite (Z 250). Buccal and lingual aspects of 90 teeth were ground flat to expose dentin, then resin composite cylinders were bonded. Initial bond strengths (n = 10) and adhesive fatigue limits (n = 20) were determined with the use of a shear test apparatus. One hundred eighty conical cavities were prepared into dentin discs and filled with the same materials. After 21 days of storage, initial push-out bond strengths (n = 10) and adhesive fatigue limits (n = 20) were measured. Sixty molars with MO cavities (n = 10) with margins below the cement-enamel junction were filled. Before and after thermomechanical loading (100000 x 50 N and 2500 x thermocycling between + 5 and + 55 degrees C), marginal gap formation and internal adaptation (only after loading) were analyzed under a SEM (x 200). The one-bottle systems showed higher shear bond strengths when evaluated statically and dynamically. However, cyclic fatigue push-out bond strengths resulted in higher values for older multistep systems. Marginal and internal gap analysis confirmed the results, in favor of older adhesive systems (p <.05; Mann-Whitney U test).     

上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷粘接及力学性能的影响

文题释义：氧化钇稳定四方相氧化锆多晶陶瓷：是以氧化钇为稳定剂、四方相为主要物相的氧化锆陶瓷，其具有较高的抗弯强度(900-1 200 MPa)和断裂韧性(9-10 MPa·m^1/2)。由于这些优异的机械性能，氧化钇稳定四方相氧化锆多晶陶瓷成为口腔冠桥修复中应用最广泛的陶瓷之一。 相变增韧机制：为氧化锆增韧的一种方法。稳定剂使四方相氧化锆在室温下可以处于亚稳态，但是在应力作用下亚稳态的四方相氧化锆易转化为单斜相氧化锆，同时伴有3%-5%的体积膨胀，这个过程能弥合微裂纹且消耗断裂能，提高氧化锆陶瓷的韧性。 背景：任何表面处理都应在不损害原有氧化钇稳定四方相氧化锆多晶陶瓷强度的前提下提高其粘接强度。目前缺乏上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷粘接强度影响的资料，并且其对氧化钇稳定四方相氧化锆多晶陶瓷力学性能的影响尚不明确。 目的：评估上釉技术对氧化钇稳定四方相氧化锆多晶陶瓷力学行为及其与树脂水门汀粘接强度的影响。 方法：制作氧化钇稳定四方相氧化锆多晶陶瓷试件并随机分为4组：A组，表面不做任何处理；B组，110 μm氧化铝颗粒喷砂；C组，上釉+氢氟酸酸蚀；D组，上釉+氢氟酸酸蚀+硅烷化。检测每组试件的表面显微形貌、粗糙度、晶相结构、元素组成、剪切粘接强度和弯曲强度，并观察剪切粘接强度测试后所有断面的断裂模式。 结果与结论：①经表面处理后的试件粗糙度明显增大，降序排列依次为C组(0.62±0.01) μm、D组(0.55±0.02) μm、B组(0.11±0.02) μm、A组(0.05±0.01) μm，5组间粗糙度比较差异有显著性意义(P < 0.05)；②B组试件表面含有2.2%单斜相氧化锆，而其他组含量均为零；③除锆和氧2种元素外，B组还含有铝元素6.49%，C和D组分别含有硅元素18.67%和25.78%；④A、B、C、D组的剪切粘接强度分别为(3.11±0.40)，(4.23±0.45)，(6.62±0.60)，(10.46±0.83) MPa，组间两两比较差异均有显著性意义(P < 0.05)；⑤A、B、C和D组的三点弯曲强度分别为(961.07±75.53)，(1 234.73±114.09)，(1 024.28±120.51)，(1 036.09±80.10) MPa，其中A、C和D组两两比较差异无显著性意义(P > 0.05)，B组与A、C、D组比较差异有显著性意义(P < 0.05)；⑥结果表明，上釉技术未明显提升氧化钇稳定四方相氧化锆多晶陶瓷的弯曲强度，但上釉后经氢氟酸蚀刻并硅烷化处理可显著增强氧化钇稳定四方相氧化锆多晶陶瓷与树脂水门汀之间的粘接强度。 ORCID: 0000-0002-8066-2498(徐小敏) 中国组织工程研究杂志出版内容重点：生物材料；骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性；组织工程     

The effect of six years of water storage on resin composite bonding to human dentin

The aim of this in vitro study was to evaluate dentin bond strength and marginal adaptation of direct resin composite fillings after different storage times. Three hundred sixty cavities were prepared in discs of freshly extracted human third molars and filled with resin composites. Multistep self-etching adhesives (Syntac Classic, A.R.T. Bond, both with and without total etching), three-step etch-and-rinse adhesives (Scotchbond Multi-Purpose Plus, EBS), and two-step etch-and-rinse adhesives (Prime and Bond 2.0, Syntac Single-Component) were used for bonding. After 1, 90, and 2190 days of water storage and 24 h thermocycling (1150 cycles), push-out testing was performed. From the 6-year group, replicas were made after 1 day, 90 days, and 1, 2, 3, 4, 5, and 6 years, and examined regarding marginal adaptation under an SEM (x 200 magnification). In all groups under investigation, push-out bond strengths remained stable after 90 days; however, the strengths significantly decreased after 6 years of water storage. The two-step systems exhibited lower bond strengths than three-step systems after 6 years. Marginal analysis revealed a significant loss regarding the percentage of perfect margins having been stable after 2 years for the three-step etch-and-rinse systems. Overall, the older three-step systems proved to be more effective than the simplified adhesives Syntac Single-Component and Prime and Bond 2.0 with regard to bond strength and marginal adaptation.     

Adhesion of composite to enamel and dentin surfaces irradiated by IR laser pulses of 0.5-35 micros duration

The characteristics of laser-treated tooth surfaces depend on the laser wavelength, pulse duration, spatial and temporal laser beam quality, incident fluence, surface roughness, and the presence of water during irradiation. Ablated surfaces are most commonly restored with adhesive dental materials and the characteristics of the ablated surfaces influence adhesion of restorative materials. Previous studies suggest that high bond strengths can be achieved using shorter laser pulses that minimize peripheral thermal damage. In this study, Er:YSGG, Er:YAG, and CO(2) lasers were used at irradiation intensities sufficient to simulate efficient clinical caries removal to uniformly irradiate bovine enamel and human dentin surfaces using a motion control system with a microprocessor-controlled water spray. The degree of spatial overlap of adjacent pulses was varied so as to investigate the influence of irradiation uniformity and surface roughness on the bond strength. Composite resin was bonded to the irradiated surfaces and shear bond tests were used to obtain bond strengths in MPa. The highest results were obtained using the Er:YAG pulses with pulse durations less than 35 mus without the necessity for postirradiation acid etching. Some of these groups were not significantly different from nonirradiated, acid-etch-only positive control groups.     

口腔粘接新型材料——磷酸二氢(甲基丙烯酰氧癸)酯的合成与应用

以甲基丙烯酸、1,10-癸二醇和三氯氧磷为主要原料合成出了磷酸二氢(甲基丙烯酰氧癸)酯.用1HNMR、MS和31P-NMR对产物结构进行了表征确认.通过剪切强度的测试评价了磷酸二氢(甲基丙烯酰氧癸)酯对复合树脂与牙釉质、牙本质、钛合金、钴铬合金和高含金合金之间的粘接性能的影响.结果表明磷酸二氢(甲基丙烯酰氧癸)酯能够促进复合树脂与牙釉质、牙本质、钛合金、钴铬合金的粘接,剪切强度分别达到13.5、11.2、16.2和18.1 MPa.     

Characterisation of resin-dentine interfaces by compressive cyclic loading

The aims of this in vitro study were to evaluate the ultra-morphological changes in resin-dentine interfaces after different amounts of thermomechanical load (TML), and to determine the corresponding microtensile bond strengths (microTBS). Enamel/dentine discs with a thickness of 2 mm were cut from 24 human third molars and bonded with four adhesives involving different adhesion approaches: Syntac (Ivoclar Vivadent; used as multi-step etch-and-rinse adhesive), Clearfil SE Bond (Kuraray; two-step self-etch adhesive), Xeno III (Dentsply DeTrey; mixed all-in-one self-etch primer adhesive system), and iBond (Heraeus Kulzer; non-mixed all-in-one self-etch adhesive). The resin-dentine discs were cut into beams (width 2 mm; 2 mm dentine, 2 mm resin composite) and subsequently subjected to cyclic TML using ascending amounts of mechanical/thermal cycles (20 N at 0.5 Hz of mechanical load and 5-55 degrees C of thermal cycles: for 0/0, 100/3, 1,000/25, 10,000/250, 100,000/2,500 cycles). Loaded specimens were either cut perpendicularly in order to measure microTBS (n=20; crosshead speed: 1 mm/min) or were immersed in an aqueous tracer solution consisting of 50 wt% ammoniacal silver nitrate and processed for ultra-morphological nanoleakage examination using transmission electron microscopy (TEM). microTBS were significantly decreased by increasing amounts of TML for all adhesives (p<0.05). Bond strengths after 0 vs. 100,000 thermomechanical cycles were: Syntac: 41.3/30.1 MPa; Clearfil SE Bond 44.8/32.5 MPa; Xeno III 27.5/13.7 MPa; iBond 27.0/6.2 MPa. Relatively early, a certain amount of nanoleakage was observed in all groups by TEM, which was more pronounced for Xeno III and iBond. The incidence of nanoleakage remained stable or was even reduced with increasing load cycles for all adhesives except iBond, where exact failure origins were detected within the adhesive and at the top of the hybrid layer.     

Adhesion to chondroitinase ABC treated dentin

Dentin bonding relies on complete resin impregnation throughout the demineralised hydrophilic collagen mesh. Chondroitin sulphate-glycosaminoglycans are claimed to regulate the three-dimensional arrangement of the dentin organic matrix and its hydrophilicity. The aim of this study was to investigate bond strength of two etch-and-rinse adhesives to chondroitinase ABC treated dentin. Human extracted molars were treated with chondroitinase ABC and a double labeling immunohistochemical technique was applied to reveal type I collagen and chondroitin 4/6 sulphate distribution under field emission in-lens scanning electron microscope. The immunohistochemical technique confirmed the effective removal of chondroitin 4/6 sulphate after the enzymatic treatment. Dentin surfaces exposed to chondroitinase ABC and untreated specimens prepared on untreated acid-etched dentin were bonded with Adper Scotchbond Multi-Purpose or Prime and Bond NT. Bonded specimens were submitted to microtensile testing and nanoleakage interfacial analysis under transmission electron microscope. Increased mean values of microtensile bond strength and reduced nanoleakage expression were found for both adhesives after chondroitinase ABC treatment of the dentin surface. Adper Scotchbond Multi-Purpose increased its bond strength about 28%, while bonding made with Prime and Bond NT almost doubled (92% increase) compared to untreated specimens. This study supports the hypothesis that adhesion can be enhanced by removal of chondroitin 4/6 sulphate and dermatan sulphate, probably due to a reduced amount of water content and enlarged interfibrillar spaces. Further studies should validate this hypothesis investigating the stability of chondroitin 4/6 and dermatan sulphate-depleted dentin bonded interface over time.     

Bonding performance of different adhesive systems to deproteinized dentin: microtensile bond strength and scanning electron microscopy

Deproteinization has been shown to optimize dentin bonding, but differences in adhesive composition should be considered. The objective of this study was to evaluate the effect of dentin deproteinization on microtensile bond strength (microTBS) of four total-etch adhesive systems (Single Bond/SB, Prime & Bond NT/PB, One Coat Bond/OC, and PQ1/PQ). The ultrastructure of the resin-dentin interfaces was also examined using scanning electron microscopy. Tukey's multiple-comparison tests indicated that PB and PQ produced significantly higher microTBS (p<0.05) after dentin deproteinization (PB=61.53 MPa, PQ=58.18 MPa). This treatment provided statistically lower results for SB (39.08 MPa), but the microTBS of OC to dentin was unaffected by dentin deproteinization. The bonding performance on deproteinized dentin surfaces depended on the characteristics of each adhesive system, as well as the adhesive dentin specificity to the oxidant effect of sodium hypochlorite. Incorporation of fillers in the adhesive, a possible self-etching action, and the presence of a volatile solvent (acetone) were the main factors for a better union between the adhesive system and deproteinized substrate.     

Effect of elapsed time following bleaching on the shear bond strength of composite resin to enamel

The purpose of this study was to investigate the effect of post-treatment time on the shear bond strength of composite resin to enamel after bleaching with 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) bleaching systems. One hundred and thirty-five flattened labial enamel surfaces obtained from human mandibular incisors were divided into two bleaching groups of 10% CP (n = 60) and 35% HP (n = 60) and a control group (n = 15). Specimens in the control group (group 1) were not bleached. Each bleaching group was then divided into four subgroups (n = 15). For both CP and HP groups, group 2 consisted of specimens bonded immediately after bleaching. In groups 3, 4, and 5, specimens were immersed in artificial saliva for 24 h, 1 week, or 2 weeks after bleaching, respectively. After the specimens were bonded with Clearfil SE Bond and Clearfil ST, they were tested in shear until failure. For both CP and HP groups, shear bond strength of composite resin to enamel that was bonded immediately after bleaching was significantly lower than that of unbleached enamel (p < 0.05). However, in CP group restored after 24 h, the bond strength returned to values close to those of nonbleached enamel (p > 0.05). It took 1 week to return to conditions that lead to control bond values for HP bleaching applications (p > 0.05). The results of this study proved that immediate bonding of composite to enamel bleached with 10% CP and 35% HP gels result in a significant decrease in shear bond strength. It is advisable that composite resin application onto bleached enamel surfaces should be delayed at least 24 h for 10% CP and 1 week for 35% HP.     

Exploration and preliminary clinical investigation of an adhesive approach for primary tooth restoration

The current study aims to investigate a suitable adhesive for primary tooth enamel. Shear bond strength (SBS) of primary teeth and the length of resin protrusion were analyzed using one-way ANOVA with Bonferroni multiple comparison tests after etching with 35% H₃PO₄. SBS and marginal microleakage tests were conducted with Single Bond Universal (SBU)/Single Bond 2 (SB2) adhesives with or without pre-etching using a nonparametric Kruskal-Wallis test. Clinical investigations were performed to validate the adhesive for primary teeth restoration using Chi-square tests. Results showed that the SBS and length of resin protrusion increased significantly with the etching time. Teeth in the SBU with 35% H₃PO₄ pre-etching groups had higher bond strength and lower marginal microleakage than those in the SB2 groups. Mixed fractures were more common in the 35% H₃PO₄ etched 30 s + SB2/SBU groups. Clinical investigations showed significant differences between the two groups in cumulative retention rates at the 6-, 12- and 18-month follow-up evaluations, as well as in marginal adaptation, discoloration, and secondary caries at the 12- and 18-month follow-up assessments. Together, pre-etching primary teeth enamel for 30 s before SBU treatment improved clinical composite resin restoration, which can provide a suitable approach for restoration of primary teeth.     

Tensile and shear adhesion of amalgam to tooth structure using selective interfacial amalgamation

Eight cavity liner systems using Selective Interfacial Amalgamation (S.I.A.) were evaluated for their ability to bond dental amalgam to tooth structure. Both punch shear and tensile adhesion along with the fracture path were evaluated. Results showed the maximum mean adhesive tensile and shear strengths to be of the order of 3.5 MPa and 15 MPa, respectively.     

不同表面处理对Ceramage聚合瓷黏结强度的影响

背景：长期以来修复材料与基牙的黏接技术一直是口腔修复学的研究热点,其中尤为引人关注的是黏结工件的表面处理工艺。 目的：对比观察8种表面处理方法对Ceramage聚合瓷黏结强度的影响,筛选适合Ceramage聚合瓷的表面处理方法。 方法：将Ceramage聚合瓷制成试件80个,随机分成8组,分别采用喷砂,酸蚀,偶联剂,喷砂+酸蚀,喷砂+偶联剂,酸蚀+偶联剂,喷砂+酸蚀+偶联剂处理聚合瓷表面并与树脂黏结剂黏结,对照组不进行任何处理。在37 ℃水浴24 h后测试样本剪切强度,并用扫描电镜观察处理后的聚合瓷表面形貌。 结果与结论：各组的剪切强度值由高到低分别为：喷砂+酸蚀+偶联剂处理组(31.12±2.81) MPa,喷砂+酸蚀组(27.62±1.70) MPa,酸蚀+偶联剂组(27.31±2.18) MPa,喷砂+偶联剂组(26.91±1.97) MPa,喷砂组(24.23±2.03) MPa,偶联剂组(23.50± 2.19) MPa,酸蚀组(17.61±2.14) MPa,对照组(8.13±0.63) MPa,除喷砂组、偶联剂组之间,喷砂+酸蚀组、喷砂+偶联剂组、酸蚀+偶联剂组之间比较差异无显著性意义外(P > 0.05),其余组间比较差异均有显著性意义(P  < 0.05)。结果显示7种表面处理方法都提高了黏结强度,喷砂、酸蚀联合硅烷偶联剂处理的聚合瓷黏结强度最高,是适合Ceramage聚合瓷黏结的表面处理方法。     

Differential effect of in vitro degradation on resin-dentin bonds produced by self-etch versus total-etch adhesives

OBJECTIVE: To evaluate the effect of an in vitro challenge (NaOCl immersion) on microtensile bond strength (MTBS) of five adhesive systems to dentin. METHODS: Flat dentin surfaces from 40 molars were bonded with three total-etch adhesives (Single Bond, Prime&Bond NT and the experimental Prime&Bond XP), and two self-etching agents (Clearfil SE Bond and Etch&Prime 3.0). Composite build-ups were constructed with Tetric Ceram. Teeth were then sectioned into beams of 1.0 mm2 cross-sectional area. Half of the beams were immersed in 10% NaOCl aqueous solution for 5 h. Each beam was tested in tension in an Instron machine at 0.5 mm/min. Data were analyzed by 2-way ANOVA and multiple comparisons tests (p < 0.05). RESULTS: Clearfil SE Bond and Single Bond attained higher MTBS than the other three adhesives. Prime&Bond NT and Prime&Bond XP performed equally, and Etch&Prime resulted in the lowest MTBS. After NaOCl immersion, MTBS decreased in all groups. The highest MTBS values were obtained for Clearfil SE Bond and Prime&Bond XP. Scaning electron microscopy observation of debonded sticks evidenced dissolution and microstructural alterations of intertubular dentin, except when Clearfil SE Bond was used. CONCLUSIONS: Resin-dentin bonds are prone to chemical degradation. The extent of the resin degradation is adhesive system specific. Chemical degradation of the nonresin infiltrated collagen fibers does also exist in total-etch adhesives. Both processes may reduce long-term resin-dentin bond strength.     

Pyruvic acid as an etching agent in clinical dentistry

The objective of this study was to evaluate the use of pyruvic acid as an alternative etching agent to phosphoric acid (H3PO4). Solutions containing 5, 10, 15, 20, 25, and 30 m/m % pyruvic acid and 50% m/m H3PO4 were prepared. The tensile bond strengths of a composite resin to enamel surfaces etched with the respective etching agents were determined. The rates of etching of enamel surfaces by each of the etching solutions were evaluated. Unground and polished enamel surfaces were etched with the respective etching solutions and the surfaces examined by scanning electron microscopy. The tensile bond strengths of the resin to enamel surfaces etched with 10-30% pyruvic acid exceeded those obtained on enamel surfaces etched with 50% H3PO4. The rates of etching of all the pyruvic acid solutions were significantly less than of H3PO4. Well-defined etching patterns were observed on the enamel surfaces etched with all the etching solutions. The results of this laboratory study suggest that pyruvic acid may be a suitable alternative to phosphoric acid as an etching agent in clinical dentistry.     

Initial adhesion of glass-fiber-reinforced composite to the surface of porcine calvarial bone

The aim of this preliminary study was to compare the initial bond strength of the glass-fiber-reinforced composite veil to the surface of the porcine calvarial compact bone using different adhesives. Fiber-reinforced composite (FRC) made of E-glass fiber veil with the BisGMA-PMMA resin system was used in the study. For the shear bond strength test, porcine calvarial bone cubes were mounted into resin matrix. FRC-veil discs were bonded to compact bone with different types of adhesives: (A) BisGMA-HEMA based (3M-ESPE Scotchbond Multi-Purpose Adhesive), (B) 4-META/UDMA/BisGMA based (Unifil Bond Bonding Agent) and MDP based (Clearfil Se Bond adhesive), (C) UDMA/BisGMA/PMMA-based experimental adhesive, and (D) silane-based (APS, ICS, MPS) experimental adhesives. The surface of the bone was mechanically roughened and was either used as such, treated with dental primers (Unifil Bond Self-etching Primer, Clearfil Se Bond Primer), or treated with an experimental silane mixture (APS, ICS, MPS), or with a mixture of the experimental silane liquid and Clearfil Se Bond Primer. The 3M-ESPE Scotchbond Multi-Purpose Adhesive and UDMA/BisGMA/PMMA experimental adhesive gave poor results in the shear bond test (0.58 and 0.40 MPa, respectively). Unifil Bond Bonding Agent and Clearfil Se Bond adhesive with respective primers markedly improved the shear bond strength; with Unifil the result was 3.40 MPa, and with Clearfil it was 6.19 MPa. When the bone surface was primed with a mixture of Clearfil Se Bond Primer and Clearfil Porcelain Bond Activator, the Clearfil Se Bond adhesive-impregnated FRC veil gave the best adhesion to the bone surface in this test: 9.50 MPa. The addition of bioactive glass granules between the veil and the bone lowered the shear bond strength in the test system described above to 6.72 MPa. The test systems with the silane mixture were also promising. In the SEM study, it was found that the mechanical treatment reveals the pores of the bone surface. Chemical treatments of the bone surface improved the adhesion of the FRC veil to the bone. The results showed that the adhesion of the FRC to the surface of the bone can be significantly improved with mechanical roughening and with special chemical treatments of the bone surface.     

Microleakage and interfacial morphology of self-etching adhesives in class V resin composite restorations

The purpose of the study was to evaluate the marginal leakage of three adhesive systems in Class V resin composite restorations. Two adhesive systems containing acidic primers: Clearfil SE Bond (CSEB) and Etch & Prime 3.0 (E&P), were compared with a conventional water-based primer: Scotchbond Multipurpose Plus (SBMP). Class V cavities were made at the cementum-enamel junction of extracted human molars, which were then divided between three groups. One of the adhesive systems was applied to each group following manufacturers' instructions. Composite restorations were placed, light cured for 40 s, and polished. Specimens were then immersed in a solution of 2% basic fuchsin dye for 24 h. Longitudinal sections were obtained and studied with a stereomicroscope for assessment of the microleakage according to the degree of dye penetration (scale of 0-3). Data were analyzed by Kruskal-Wallis one-way ANOVA, Mann-Whitney tests, and the Wilcoxon matched-pairs signed rank test. Two specimens for each group were analyzed by scanning-electron microscopy (SEM). Bonded interfaces of dentin were also examined by transmission-electron microscopy (TEM). On enamel, there were no significant differences between the three groups. On dentin, CSEB showed the lowest dye penetration values among the three adhesive systems. SEM and TEM studies showed hybrid layer and resin tag formations in all groups.     

Efficacy of varying the NMEP concentrations in the NMGly-NMEP self-etching primer on the resin-tooth bonding

It is well understood that the application of a self-etching primer enhances the bonding at the resin-teeth interface. In this study, we designed a self-etching primer consisting of N-methacryloyl glycine (NMGly) and N-methacryloyl-2-aminoethyl phosphonic acid (NMEP). The demineralization effects on the hydroxyapatite or dentin by the carboxylic acid in the NMGly and by the phosphonic acid in the NMEP and their effects on the bond strength of the resin to the tooth were examined. The application of the NMGly-NMEP solution to the enamel resulted in an increase in the bond strength when additional amounts of NMEP were added to the NMGly aqueous solution. This increase was due to the phosphonic acid in the NMEP demineralizing the enamel. Conversely, the addition of the NMEP to the NMGly solution resulted in a decrease in the bond strength to the dentin. The optimal concentration of the NMEP in the NMGly-NMEP solution resulted in bond strengths of over 20 MPa for both the enamel and dentin.     

Shear bond strength of a hot pressed Au-Pd-Pt alloy-porcelain dental composite

Objectives: The purpose of this study was to evaluate the effect of hot pressing on the shear bond strength of a Au-Pt-Pd alloy-porcelain composite. Methods: Several metal-porcelain composites specimens were produced by two different routes: conventional porcelain fused to metal (PFM) and hot pressing. In the latter case, porcelain was hot pressed onto a polished surface (PPPS) as well as a roughened one (PPRS). Bond strength of all metal-porcelain composites were assessed by the means of a shear test performed in a universal test machine (crosshead speed: 0.5?mm/min) until fracture. Interfaces of fractured specimens as well as undestroyed interface specimens were examined with optical microscope, stereomicroscope, Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). The data were analyzed using one-way ANOVA followed by Tuckey's test (p<0.05). Results: Shear bond strength of conventional PFM specimens were in line with the upper range of literature data (83±14?MPa). Hot pressing proved to significantly increase bond strength between metal and porcelain (p<0.05). For both polished and roughened surface the shear bond strength values for hot pressed specimens were 120±16?MPa and 129±5?MPa, respectively, which represents an improvement of more than 50% relatively to a conventional PFM. Roughened surface did not have a significant effect on bond strength of hot pressed specimens (p>0.05). Significance: This study shows that it is possible to significantly improve metal-porcelain bond strength by applying an overpressure during porcelain firing.