氢氟酸处理时间对玻璃陶瓷与树脂粘接耐久性的影响

目的 评价不同氢氟酸处理时间对玻璃陶瓷表面与树脂粘接耐久性的影响,以期为玻璃陶瓷表面氢氟酸处理时间的正确选择提供临床参考.方法 可切削玻璃陶瓷(PmCAD)表面接受4.8%氢氟酸处理0 s(对照组)、30 s(30 s氢氟酸处理组)和60 s(60 s氢氟酸处理组),每组32个陶瓷片.使用三维激光共聚焦显微镜测量陶瓷片表面粗糙度参数(Ra)和表面积.陶瓷片与4种粘接套装(硅烷偶联剂和树脂粘接剂:A:Monobond S和Variolink Ⅱ;B:Clearfil Ceramic Primer和Clearfil Esthetic Cement;C:GC Ceramic Primer和Linkmax HV;D:Porcelain Liner M和SuperBond)粘接形成粘接试件,每组16个陶瓷片直接测量粘接强度,16个陶瓷片经30 000次冷热循环后测量粘接强度.结果 对照组、30和60 s氢氟酸处理组Ra值[分别为(3.89±1.94)、(12.53±0.80)、(13.58±1.10)μm]及表面积[分别为(7.81±2.96)、(30.18±2.05)、(34.16±1.97)mm2]随着氢氟酸处理时间的延长而显著增加(P<0.05).同种粘接套装相同氢氟酸处理时间下冷热循环后试件的粘接强度均显著低于冷热循环前(P<0.05).冷热循环后粘接套装A、B的粘接强度随着氢氟酸处理时间的延长而显著增加[A:分别为(3.59±3.51)、(16.18±2.62)、(20.33±2.45)Mpa;B:分别为(4.74±2.08)、(7.77±1.55)、(13.45±3.75)Mpa];粘接套装D 30 s氢氟酸处理组的粘接强度[(22.00±1.64)Mpa]显著高于相应对照组[(12.96±4.17)Mpa],但与60 s氢氟酸处理组[(20.42±3.01)Mpa]相比,差异无统计学意义(P>0.05);氢氟酸处理时间未对粘接套装C的粘接强度产生显著影响.结论 氢氟酸处理能提高玻璃陶瓷与树脂的粘接耐久性,氢氟酸处理时间的选择不仅取决于陶瓷表面结构的变化,也取决于所使用的粘接套装.     

Intra‐oral adhesive systems for ceramic repairs: a comparison

The aim of this investigation was to compare the bond strength of restorative composite resin to dental ceramic conditioned with primers and adhesives of various commercial repair kits. Three intra‐oral ceramic repair systems—Silistor (Heraeus Kulzer), Cimara (Voco), Ceramic Repair (Vivadent)—were used on all‐ceramic (IPS Empress 2, Ivoclar‐Vivadent) substrate. Shear bond strength of restorative composite resin to substrate was tested after thermocycling and without thermocycling (n=10). Substrate surfaces of the specimen after loading were examined microscopically (SEM). The highest bond strengths in both water‐stored (7.0±5.7 MPa) and thermocycled conditions (2.5±1.8 MPa) were obtained with the Vivadent repair system, while the lowest values were observed with the Cimara system (0.6±1.4 MPa and 0.0±0.0 MPa, respectively). Shear bond strengths appeared to be significantly affected by thermocycling (ANOVA, P<0.05). It is concluded that there are significant differences in the bond strengths of resin composites and ceramic substrate. The roughened surface does not necessarily provide a better bond strength; the bond strength of composite decreases with storage in water and after thermocycling. Bond strength values were generally low for all of the tested materials.     

Porcelain repair - Influence of different systems and surface treatments on resin bond strength

PURPOSE

The purpose of this study was to evaluate the bond strength of composite resin on the fracture surface of metal-ceramic depending on the repair systems and surface roughening methods.

MATERIALS AND METHODS

A total of 30 disk specimens were fabricated, 15 of each were made from feldspathic porcelain and nickel-chromium base metal alloy. Each substrate was divided into three groups according to the repair method: a) application of repair system I (Intraoral Repair Kit) with diamond bur roughening (Group DP and DM), b) application of repair system I with airborne-particle abrasion (Group SP and SM), and c) application of repair system II (CoJet Intraoral Repair System, Group CP and CM). All specimens were thermocycled, and the shear bond strength was measured. The data were analyzed using the Kruskal-Wallis analysis and the Mann-Whitney test with a significance level of 0.05.

RESULTS

For the porcelain specimens, group SP showed the highest shear bond strength (25.85 ± 3.51 MPa) and group DP and CP were not significantly different. In metal specimens, group CM showed superior values of bond strength (13.81 ± 3.45 MPa) compared to groups DM or SM.

CONCLUSION

Airborne-particle abrasion and application of repair system I can be recommended in the case of a fracture localized to the porcelain. If the fracture extends to metal surface, the repair system II is worthy of consideration.     

Influence of mechanical and chemical pre-treatments on the repair of a hybrid ceramic

ObjectivesThis study aimed to investigate the influence of the respective mechanical and chemical pre-treatments on the composite repair of a CAD/CAM hybrid ceramic using a microtensile bond strength test (μTBS).Methods15 CAD/CAM Blocks of Vita Enamic (VE) were randomly sectioned into three mechanical pre-treatments: (1.) Diamond bur (D), (2.) Airborne abrasion (A), (3.) Tribochemical silica coating (T) and subsequently five chemical pre-treatments: (1.) Clearfil SE Bond Bond (B; negative control), (2.) ESPE Sil (S), (3.) Clearfil Ceramic Primer Plus (CPP), (4.) Clearfil Repair (CR) and (5.) Scotchbond Universal (SCB). Per block, n = 20 specimens were sawn. Half of the specimens were randomly selected and subjected to an immediate bond strength test, while the other half was subjected to artificial aging for 6 months 180 days at 37 °C and subsequent thermocycling of 5000 cycles. A μTBS was performed and data (MPa) were compared in one-way and two-way ANOVA and Tukey's HSD. Paired-t-test was used for artificial aging (α = 0.05). Debonded specimens were analyzed of for failure modes with a stereomicroscope (SEM).ResultsThe results of one-way ANOVA for the fifteen fastening procedures after aging indicated significant differences according to SCB-A and CPP-T. Two-way ANOVA after aging observed inferior bond strength for SCB. No differences were observed for mechanical pre-treatments. Artificial aging showed a significant reduction in bond strength on most of the fastening procedures.SignificanceSCB showed the lowest bond strength values besides B, S, CPP, and CR. MDP and silane are both suitable for the repair of VE.     

Twenty-four hour bond strength between layers of a highly loaded indirect composite

This study evaluated the repair bond strength of Estenia composite. Disk specimens of a dentin material were conditioned with varying combinations of silane primer (Add-on Primer, Clearfil Porcelain Bond Activator, Clearfil Porcelain Bond Activator + Clearfil Mega Bond-Primer, Porcelain Liner M, and unprimed) and bonding agent (Clearfil Mega Bond-Bond, Modeling Liquid, Stain Diluent, and no bonding agent). After photopolymerization of the enamel material placed on each surface, the specimens were either wet- or dry-stored at 37 degrees C for 24 hours. Average shear bond strength varied from 24.9 to 61.4 MPa, where the Clearfil Porcelain Bond Activator + Clearfil Mega Bond-Bond group and the Add-on Primer + Modeling Liquid group showed the greatest bond strength for dry and wet conditions respectively. To achieve reliable bond strength between layers of Estenia composite, it is highly recommended to use specific combinations of silane primer and bonding agent.     

Bond strength between machinable glass-ceramic and dual-cured resin luting cements using silane coupling agents

PURPOSE: To evaluate the shear bond strength of two dual-cured resin luting cements (Linkmax HV and Panavia Fluoro Cement) to machinable glass-ceramics (Decsy Machinable Ceramic) and the effect of three silane coupling agents (Clearfil Porcelain Activator, Ceramic Primer, and Porcelain Liner M) on the bond strength. METHODS: Disk-shaped specimens fabricated from machinable glass-ceramic blocks using a low-speed cutting saw were either treated or not treated with one of three silane coupling agents and then bonded together with one of two dual-cured resin luting cements. Specimens were stored in water at 37degrees C for 24 hours and/or thermal cycled 50,000 times before shear bond strength testing. RESULTS: Regardless of the resin luting cement and thermal cycling, specimens treated with the Clearfil Porcelain Activator showed the highest shear bond strength among all the treatments. Surface treatment of the Clearfil Porcelain Activator showed significantly greater shear bond strength after 50,000 thermocycles compared with other treatments. However, significant differences in bond strength were observed between 0 and 50,000 thermocycles for all treatments.     

Bonding between resin luting cement and glass infiltrated alumina-reinforced ceramics with silane coupling agent

The purpose of this study was to evaluate the shear bond strengths of three dual-cured resin luting cements (Linkmax HV, Panavia Fluoro Cement, and RelyX ARC) to glass-infiltrated alumina-reinforced ceramic material and the effect of four silane coupling agents (Clearfil Porcelain Bond, GC Ceramic Primer, Porcelain LinerM, and Tokuso Ceramic Primer) on the bond strength. The two type-shaped of In-Ceram alumina ceramic glass-infiltrated specimens were untreated or treated with one of the four ceramic primers and then cemented together with one of the three dual-cured resin luting cements. Half of the specimens were stored in water at 37 degrees C for 24 h and the other half thermocycled 20,000 times before shear bond strength testing. Surface treatment by all silane coupling agents improved the shear bond strength compared with non-treatment. The specimens treated with Clearfil Porcelain Bond showed significantly greater shear bond strength than any of the other three silane coupling agents regardless of resin luting cements and thermocycling except for the use of Panavia Fluoro Cement at 20,000 thermocycles. When the alumina-reinforced ceramic material was treated with any silane coupling agent except GC Ceramic Primer and cemented with Linkmax HV, no significant differences in bond strength were noted between after water storage and after 20,000 thermocycles. After 20,000 thermocycles, all specimens except for the combined use of Clearfil Porcelain Bond or GC Ceramic Primer and Linkmax HV and GC Ceramic Primer and Panavia Fluoro Cement showed adhesive failures at the ceramic-resin luting cement interface.     

Metal surface treatment: characterization and effect on composite-to-metal bond strength

This study evaluated the effect of four methods of metal surface preparation and the use of silane on the bond strength between resin and a Noble metal alloy. SEM Examination and x-ray energy-dispersive spectroscopy (EDS) of the various metal surface treatments was also performed. One-hundred metal disks were cast in a Noble metal alloy (Porcelain #76). Ninety disks were polished flat and the surfaces received one of four abrasive treatments (n = 20). 1) Roughening with a diamond bur at high speed; 2) Air abrasion with an intraoral sandblaster using alumina particles; 3) Air abrasion with KCP-2000 and 4) Air abrasion with an intraoral sandblaster using silanated silica covered alumina particles (CoJet-Sand). Half the specimens from each treatment group (n = 10) were silanated prior to bonding procedures (All-Bond 2 adhesive system, Pertac-Hybrid composite). Specimens were stored in distilled water at 37 degrees C and thermocycled prior to shear strength testing. The 10 remaining metal disks were used for scanning electron microscopy and x-ray energy-dispersive spectroscopy (EDS). Scanning electron microscopy examined the micromorphology of the metal surfaces produced by the four abrasive treatments and x-ray energy-dispersive spectroscopy (EDS) to evaluate changes in surface composition. Two untreated disks served as controls. One-way ANOVA and Tukey's HSD post-hoc test demonstrated that air abrasion with CoJet-Sand and silane resulted in significantly higher resin-to-metal bond strength than all other metal surface treatments, while roughening with a diamond bur produced the lowest bond strength. Resin-to-metal bond strength was similar for all other particle abrasive treatments with or without silane. Using silane significantly improved bond strength only for metal surfaces treated with CoJet-Sand. An increase in Al concentration was observed on metal surfaces sandblasted with aluminum oxide, and an increase in the concentration of both Al and Si was observed on surfaces air-abraded with CoJet-Sand.     

Bond strength of composite to porcelain treated with new porcelain repair agents.

In vitro tensile bond strengths of composite to porcelain were evaluated using three pretreatments (HF etching, sandblasting, diamond abrasion) of the porcelain, four bonding agents (Clearfil Porcelain Bond, Porcelain Liner M, Porcelain Liner M with Super-Bond C&B, and Scotchprime) and two storage conditions (24 h and thermocycling). The overall coefficient of variation was 27%. Significant differences among bond strengths were observed, with storage condition being the most important factor, followed by bonding agent and then pretreatment. Thermocycling decreased the bond strength of all samples, but samples treated with Scotchprime were affected least. For 24 h storage, Clearfil Porcelain Bond and Scotchprime had bond strengths above 23 MN/m2 to sandblasted porcelain.     

热循环和机械循环对切削Ti2448和纯钛金瓷结合强度的影响

目的 研究热循环和机械循环对切削Ti2448和纯钛金瓷结合强度的影响。方法 按照ISO 9693的标准分别制作纯钛和Ti2448烤瓷试件各30个,每种试件均随机分为3组,A组为对照组,在37 ℃水浴中保存24 h;B组和C组在5~55 ℃水浴中热循环3 000次,在每一个温度下保持60 s,然后采用载荷50 N、频率4 Hz,机械循环20 000次（B组）或40 000次（C组）。采用三点弯曲实验测试试件的金瓷结合强度,通过扫描电镜和能谱分析金瓷剥脱面和金瓷结合界面的显微结构和成分组成,对结果进行两因素方差分析和Tukey检验。结果 A组中,纯钛试件的金瓷结合强度（29.21 MPa±2.20 MPa）明显小于Ti2448试件（44.86 MPa±1.75 MPa）（P<0.01）;纯钛试件和Ti2448试件中,C组与A组之间均有统计学差异（P<0.01）。扫描电镜和能谱分析结果显示,Ti2448瓷剥脱面有明显的瓷残留,而纯钛瓷剥脱面无明显瓷残留。结论 热循环和机械循环处理降低了Ti2448和纯钛的金瓷结合强度。     

Durability of bond between an indirect composite veneering material and zirconium dioxide ceramics

Abstract

Objective. The purpose of the present study was to evaluate the durability of bond strength between an indirect composite material and zirconia ceramics after thermocycling (100 000 cycles) and to assess the effect of various priming agents for zirconia surface treatments. Materials and methods. A CAD/CAM system (Katana, Noritake Dental Supply) was used to fabricate 96 zirconia disks as a bonding substrate. The specimens were randomly divided into six groups (n = 16) and treated with one of the following acidic priming agents: Alloy Primer (ALP, Kuraray), Clearfil Ceramic Primer (CCP, Kuraray), Clearfil Photo Bond (CPB, Kuraray), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB + Activator, Kuraray), Estenia Opaque Primer (EOP, Kuraray) and Porcelain Liner M Liquid A (PLA, Sun Medical). The specimens were bonded with an indirect composite material (Estenia C&B Dentin, Kuraray). Shear bond strengths were tested before and after 100 000 thermocycles and the data were analyzed by using the Steel-Dwass test and Mann-Whitney U-test. Results. After 100 000 thermocycles, the PLA group showed the lowest bond strength (p = 0.010), whereas the CPB + Activator (23.9 MPa; p < 0.014) and CPB (22.7 MPa; p < 0.028) groups had significantly higher bond strengths than the other groups. The Mann-Whitney U-test revealed that bond strengths did not significantly decrease after thermocycling, except for specimens in the PLA (p = 0.038) and CCP (p = 0.028) groups. Conclusions. Application of a combination of hydrophobic phosphate monomer (MDP) and initiator results in a durable long-term bond between Katana zirconia and Estenia C&B composite material.     

不同喷砂条件对选择性激光熔覆钴铬合金金瓷结合强度影响的研究

目的 研究不同的喷砂条件对选择性激光熔覆技术（SLM）制作的钴铬合金与瓷结合强度的影响。方法 用SLM技术制得63个10 mm×10 mm×2 mm钴铬合金试件块,随机分9组（n=7）,采用不同Al₂O₃粒度（A1=50 μm,A2=100 μm,A3=150 μm）和不同压强（B1=0.2 MPa,B2=0.4 MPa,B3=0.6 MPa）进行喷砂处理。每组随机选取一个试件进行扫描电子显微镜（SEM）观察,其余试件上瓷后用万能测试机测定试件的金瓷结合强度并观察其断裂模式,运用SPSS 17.0软件分析数据。结果 A1B1、A1B2、A1B3、A2B1、A2B2、A2B3、A3B1、A3B2、A3B3组剪切强度分别为（27.22±0.95）、（27.58±0.47）、（26.80±0.71）、（27.54±0.78）、（30.75±0.43）、（26.93±0.88）、（28.18±0.93）、（29.55±0.57）、（28.11±0.91） MPa。不同粒度Al₂O₃喷砂组间剪切强度的差异有统计学意义（P<0.05）,不同压强喷砂组间剪切强度的差异有统计学意义（P<0.05）,不同颗粒和不同压强对剪切强度的大小有交互作用（P<0.05）。剪切实验后,全部试件均为混合断裂模式。结论 在本实验条件下,SLM钴铬合金在0.4 MPa、100 μm的Al₂O₃颗粒喷砂后,金瓷结合强度最大。     

Influence of Surface Treatment on the Shear Bond Strength of Ceramics Fused to Cobalt–Chromium

Purpose: To evaluate the influence of surface treatment on the shear bond strength between a Co‐Cr alloy and two ceramics. Materials and Methods: Forty‐eight metal cylinders were made (thickness: 4 mm, height: 3.7 mm) according ISO TR 11405. The 48 metallic cylinders were divided into four groups (n = 12), according to the veneering ceramic (StarLight Ceram and Duceram Kiss) and surface treatments: air‐particle abrasion with Al₂O₃ or tungsten drill (W). Gr1: StarLight + Al₂O₃; Gr2: StarLight + W; Gr3: Duceram + Al₂O₃; and Gr4: Duceram + W. The specimens were aged using thermal cycling (3000×, 5 to 55°C, dwell time: 30 seconds, transfer time: 2 seconds). The shear test was performed with a universal testing machine, using a load cell of 100 kg (speed: 0.5 mm/min) and a specific device. The bond strength data were analyzed using ANOVA and Tukey's test (5%), and the failure modes were analyzed using an optical microscope (30×). Results: The means and standard deviations of the shear bond strengths were (MPa): G1 (57.97 ± 11.34); G2 (40.62 ± 12.96); G3 (47.09 ± 13.19); and G4 (36.80 ± 8.86). Ceramic (p= 0.03252) and surface treatment (p= 0.0002) significantly affected the mean bond strength values. Conclusions: Air‐particle abrasion with Al₂O₃ improved the shear bond strength between metal and ceramics used.     

Repair strength of etched vs silica-coated metal-ceramic and all-ceramic restorations

The purpose of this in vitro study was to examine shear bond strengths of composite resin to metal-exposed porcelain-fused-to-metal (PFM) and all-ceramic restorations after silica coating or etching with 5% hydrofluoric acid (HF). Specimens were fabricated for each of the following groups: two all-ceramic materials [a feldspathic porcelain (Vita Mark II) and a leucite-reinforced glass-ceramic (IPS Empress)], and one noble metal-ceramic (Orplid Keramik I alloy; Vita VMK 68 N felspathic veneer ceramic). These groups were repaired with resin composites after different pretreatment methods. In one metal-ceramic subgroup the surface exhibited a 50% metal and 50% ceramic exposure. In the silica-coating groups, the specimen surfaces were air abraded with silica acid-modified Al2O3 (CoJet Sand) and treated corresponding to the porcelain repair with resin composite. For control groups, the surfaces were etched with 5% HF for 60 seconds and treated in the same way as the silica-coated groups. After 24 hours of storage (distilled water, 37 degrees C) and an additional 24 hours of thermocycling (1150 x 5 degrees C/55 degrees C) the specimens were debonded using a shear bond strength test (n = 15). In all groups the silica coat repair achieved equal or significantly higher bond strengths than did the etching technique (p < 0.05, Mann-Whitney U test). In the metal-exposed group, the mean bond strength increased from 7.3 MPa to 16.3 MPa following the silica-coat repair. Results indicated that silica coating represents a suitable treatment for the intraoral repair of the materials tested in the present study.     

Bonding effectiveness to different chemically pre-treated dental zirconia

Objective

The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia.

Methods

Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed.

Results

Weibull analysis revealed the highest Weibull scale and shape parameters for the ‘Clearfil Ceramic Primer/mechanical ageing’ combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability.

Conclusion

Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia.

Clinical relevance

As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.     

Comparative strength of metal-ceramic and metal-composite bonds after extended thermocycling

The relative strengths of ceramic-to-metal and composite-to-metal bonds were compared after prolonged thermocycling. A total of 104 cast discs were produced from a gold alloy (Pontor LFC). A ceramic material (Duceragold) was fused to 24 discs to assess the strength of the metal-ceramic bond. An indirect composite material (New Metacolor Infis) was bonded to the remaining discs after surface preparation by Rocatec tribochemical coating, tin plating and priming with a phosphate conditioner [10-methacryloyloxydecyl dihydrogen phosphate (MDP), Cesead II], priming with a thione conditioner (V-Primer) or no treatment (unprimed control). Shear bond strengths were determined before and after thermocycling at 20,000 and 100,000 cycles. Pre-thermocycling bond strengths were ranked in the order: metal-ceramic (40.5 MPa); Rocatec treatment (33.1 MPa) and tin plating-MDP (31.0 MPa); V-Primer (20.9 MPa); and control (11.9 MPa). The bond strengths of the first three groups were not significantly different after 20,000 thermocycles, whereas those of the V-Primer and control groups were significantly reduced. After extended thermocycling (100,000 cycles) the metal-ceramic group had the highest mean shear bond strength (28.5 MPa; P < 0.05), followed by the Rocatec (23.9 MPa) and tin plating-MDP (22.1 MPa) groups. The metal-ceramic bond was the most durable, although its strength was reduced by 29.6% after extended thermocycling. On the basis of these results, we recommend the Rocatec and tin plating-MDP systems for composite-to-metal bonding. Metal-ceramic bonding, however, is superior to metal-composite bonding within the limitation of the current experiment.     

A comparative study on the bond strength of porcelain to the millingable Pd-Ag alloy

PURPOSE

The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys.

MATERIALS AND METHODS

Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe''s tests (α=.05).

RESULTS

The 3-point bending test showed the strongest (40.42 ± 5.72 MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy (37.71 ± 2.46 MPa), precious metal alloy containing 83% of gold (35.89 ± 1.93 MPa), and precious metal alloy containing 32% of gold (34.59 ± 2.63 MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05).

CONCLUSION

The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).     

Effects of the rare earth element lanthanum on the metal-ceramic bond strength of dental casting Co-Cr alloys

Statement of problem

The metal-ceramic bond strength of dental casting Co-Cr alloys may be improved by the addition of the rare earth element lanthanum (La), but studies are lacking.

Intra-oral adhesive systems for ceramic repairs: a comparison

The aim of this investigation was to compare the bond strength of restorative composite resin to dental ceramic conditioned with primers and adhesives of various commercial repair kits. Three intra-oral ceramic repair systems--Silistor (Heraeus Kulzer), Cimara (Voco), Ceramic Repair (Vivadent)--were used on all-ceramic (IPS Empress 2, Ivoclar-Vivadent) substrate. Shear bond strength of restorative composite resin to substrate was tested after thermocycling and without thermocycling (n = 10). Substrate surfaces of the specimen after loading were examined microscopically (SEM). The highest bond strengths in both water-stored (7.0 +/- 5.7 MPa) and thermocycled conditions (2.5 +/- 1.8 MPa) were obtained with the Vivadent repair system, while the lowest values were observed with the Cimara system (0.6 +/- 1.4 MPa and 0.0 +/- 0.0 MPa, respectively). Shear bond strengths appeared to be significantly affected by thermocycling (ANOVA, P < 0.05). It is concluded that there are significant differences in the bond strengths of resin composites and ceramic substrate. The roughened surface does not necessarily provide a better bond strength; the bond strength of composite decreases with storage in water and after thermocycling. Bond strength values were generally low for all of the tested materials.