Adhesive bonding of a lithium disilicate ceramic material with resin-based luting agents

This study evaluates the bonding characteristics of a lithium disilicate-based ceramic material (IPS Empress 2). Two sizes of disk specimens of the material were made, and three groups of disk pairs were separately surface-prepared using three techniques; etching with phosphoric acid, etching with hydrofluoric acid, and air-abrasion with alumina. Each group was further divided into four sub-groups; group (i) was bonded with the Variolink II composite, (ii) was treated with the Monobond-S silane primer and bonded with the Variolink II composite, (iii) was bonded with the Super-Bond acrylic adhesive and (iv) was treated with the Porcelain Liner M silane primer and bonded with the Super-Bond acrylic adhesive. Shear bond strengths were determined before and after 100 000 thermocycles. Bond strength varied from 10.6 to 71.5 MPa before thermocycling, whereas post-thermocycling bond strength ranged from 0 to 61.2 MPa. Among the three surface preparations, hydrofluoric acid etching (HF) was most effective in enhancing bond strength of both luting materials, especially for unsilanized specimens. Application of the silane primer elevated bond strength of both luting agents regardless of surface preparation method. It can be concluded, for both luting agents, that durable bond to the Empress 2 ceramic material can be achieved through the combined application of HF and the proprietary silane primer.     

Bonding of silver-palladium-copper-gold alloy with thiol derivative primers and tri-n-butylborane initiated luting agents

summary This in vitro study evaluated the effect of two primers on bond strengths and durability of luting agents joined to a silver-palladium-copper-gold alloy. One primer (Metal Primer) contained methacryloyloxyalkyl thiophosphate derivative (MEPS). The other primer (V-Primer) contained 6-(4-vinylbenzyI- n -propyl)aniino-l,3,5-triazine-2,4-dithiol (VTD). The luting agent was a methyl methacrylate (MMA)-based adhesive resin that contained 4-methacryloyloxyethyl trimellitate anhydride (4-META) and was initiated with tri- n -butylborane derivative (TBB). In order to evaluate the function of 4-META, MMA-TBB resin without 4-META was used as a control. The alloy specimens were bonded with six combinations of two primers and two luting agents. Shear bond strengths were determined before and after thermocycling. Both primers significantly elevated the bond strengths of the luting agents joined to the alloy. For unprimed groups, 4-META resin showed a more durable bond than did MMA-TBB resin. Combined use of Metal Primer with 4-META resin reduced the bond strength, while combination of V-Primer and 4-META resin did not affect the bond strength.     

Adhesive bonding of titanium with a methacrylate–phosphate primer and self-curing adhesive resins

SUMMARY The adhesive bonding of titanium was evaluated with the use of a metal primer and three types of self curing luting agent. The primer contained 10-methacryloyloxydecyl dihydrogen phosphate (MDP). One luting agent was a composite material that contained the MDP monomer in its liquid part. The other luting agent was based on methyl methacrylate (MMA), initiated with tri-n-butylborane derivative (TBB), and contained 4-methacryloyloxyethyl trimellitate anhydride (4-META). The MMA-TBB resin without 4-META was used for the control. Pure titanium metal specimens were bonded with various combinations. Shear bond strengths were determined after repeated thermocycles in water. Both MDP and 4-META were effective in bonding titanium. The decrease in bond strength was minimum when the titanium was primed with MDP and then bonded with the TBB-initiated resins.     

Improved bonding of adhesive resin to sintered porcelain with the combination of acid etching and a two-liquid silane conditioner

This study determined the bond strengths of adhesive resins joined to a feldspathic porcelain (VMK 68) for the purpose of developing the most durable surface preparation for the porcelain. Three porcelain surfaces-ground, air-abraded with alumina, and etched with hydrofluoric acid-were prepared. A two-liquid porcelain conditioner that contained both 4-methacryloyloxyethyl trimellitate anhydride (4-META) and a silane coupler (Porcelain Liner M) was used as the priming agent. Each of the two liquid components of the conditioner was also used individually in order to examine the effects of the respective chemical ingredients on adhesive bonding. Two methyl methacrylate (MMA)-based resins initiated with tri-n-butylborane (TBB) either with or without 4-META (MMA-TBB and 4-META/MMA-TBB resins) were used as the luting agents. Shear bond strengths were determined both before and after thermocycling. Shear testing results indicated that thermocycling was effective for disclosing poor bonding systems, and that both mechanical and chemical retention were indispensable for bonding the porcelain. Of the combinations assessed, etching with hydrofluoric acid followed by two-liquid priming with the Porcelain Liner M material generated the most durable bond strength (33.3 MPa) for the porcelain bonded with the 4-META/MMA-TBB resin (Super-Bond C&B).     

Comparison of four fluoride etchants in bonding between titanium and a self-curing luting agent

The purpose of the present study was to investigate the efficacy of four different fluoride etchants in titanium bonding. The etchants were aqueous solutions of 5 wt% sodium fluoride (NaF), ammonium fluoride (NH4F), sodium hydrogen fluoride (NaFHF), and ammonium hydrogen fluoride (NH4FHF). Cast specimens of commercially pure titanium were air-abraded with alumina, etched for 30 seconds, and then primed with a phosphate primer. An acrylic rod was bonded to the specimen with a tri-n-butylborane-initiated self-curing luting agent. Shear bond strengths were determined before and after 10,000 thermocycles. Regarding pre-thermocycling bond strength, there were no significant differences among the etchants. After thermocycling, there was a decrease in bond strength for all groups. Nonetheless, the bond strengths of NaFHF and NH4FHF were significantly higher than those of NaF, NH4F, and non-etched control. In terms of bonding durability between resin and titanium, it was significantly improved when the titanium surface was microscopically roughened with alumina blasting and etching using NaFHF or NH4FHF.     

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.     

Fatigue resistance of the bond of a glass-infiltrated alumina ceramic to human dentin

PURPOSE: To evaluate the fatigue resistance of the bond between dentin and glass-infiltrated alumina ceramic, using different luting protocols. MATERIALS AND METHODS: The null hypothesis is that the fatigue resistance varies with the luting strategy. Forty blocks of In-Ceram Alumina were prepared, and one surface of each block was abraded with 110-microm aluminum oxide particles. Then, the blocks were luted to flat dentin surfaces of 40 human third molars, using 4 different luting strategies (luting system [LS]/ceramic surface conditioning [CSC]) (n=10): (G1) [LS] RelyX-Unicem/[CSC] airborne abrasion with 110-microm Al2O3 particles; (G2) [LS] One-Step + Duo-Link (bis-GMA-based resin)/[CSC] etching with 4% hydrofluoric acid + silane agent; (G3) [LS] ED-Primer + Panavia F (MDP-based resin)/[CSC] Al2O3; (G4) [LS] Scotchbond1+RelyX-ARC (bis-GMA-based resin)/[CSC] chairside tribochemical silica coating (air abrasion with 30-microm SiOx particles + silane). After 24 h of water storage at 37 degrees C, the specimens were subjected to 106 fatigue cycles in shear with a sinusoidal load (0 to 21 N, 8 Hz frequency, 37 degrees C water). A fatigue survivor score was given, considering the number of the fatigue cycles until fracture. The failure modes of failed specimens were observed in a SEM. RESULTS: G3 (score = 5.9, 1 failure) and G4 (score = 6, no failures) were statistically similar (p = 0.33) and had significantly higher fatigue resistance than G1 (score = 3.9, 5 failures) and G2 (score = 3.7, 6 failures) (p < 0.03). SEM analysis of fractured specimens of G1 and G2 showed that almost all the failures were between ceramic and cement. CONCLUSION: The MDP-based resin cement + sandblasting with Al2O3 particles (G3) and bis-GMA-based resin cement + tribochemical silica coating (G4), both using the respective dentin bonding systems, were the best luting protocols for the alumina ceramic. The null hypothesis was confirmed.     

Mechanical Properties of Dual-Cured Resin Luting Agents for Ceramic Restoration

PURPOSE: The aim of the present study was to evaluate mechanical properties, including surface hardness, flexural strength, and flexural modulus, of two dual-cured resin luting agents [Clearfil Esthetic Cement (CEC) and Variolink II (VLII)] irradiated through four thicknesses of leucite ceramics (0, 1, 2, and 3 mm) and to evaluate their shear bond strength to zirconia ceramic (Cercon) using each ceramic primer. MATERIALS AND METHODS: Knoop hardness was measured on a thin layer of resin luting agent on the ceramic surface. Three-point bending tests were performed after 24 hours of storage at 37 degrees C. Two differently shaped zirconia ceramic specimens with or without sandblasting with alumina were treated with each primer. The specimens were then cemented together with each resin luting agent. Half of the specimens were stored in water at 37 degrees C for 24 hours and the other half were thermocycled 5000 times. RESULTS: VLII revealed statistically higher Knoop hardness and flexural modulus than CEC for each thickness of ceramic. No significant differences in flexural strength were observed between VLII and CEC for each ceramic spacer. Reduction of the mechanical properties with increase of ceramic thickness varied for each property; however, these properties were similar in the two materials. Blasting with alumina was significantly effective for increasing shear bond strength of both resin luting agents before and after thermal cycling. The use of Clearfil Ceramic Primer showed the highest shear bond strength and maintained bond durability after 5000 thermocycles. CONCLUSION: Mechanical properties of CEC dual-cured resin luting agent appear adequate for ceramic restorations.     

Bonding polycarbonate brackets to ceramic: effects of substrate treatment on bond strength.

This study evaluated the effects of 5 different surface conditioning methods on the bond strength of polycarbonate brackets bonded to ceramic surfaces with resin based cement. Six disc-shaped ceramic specimens (feldspathic porcelain) with glazed surfaces were used for each group. The specimens were randomly assigned to 1 of the following treatment conditions of the ceramic surface: (1) orthophosphoric acid + primer + bonding agent, (2) hydrofluoric acid gel + primer + bonding agent, (3) tribochemical silica coating (silicon dioxide, 30microm) + silane, (4) airborne particle abrasion (aluminum trioxide, 30microm) + silane, and (5) airborne particle abrasion (aluminum trioxide, 30microm) + silane + bonding agent. Brackets were bonded to the conditioned ceramic specimens with a light-polymerized resin composite. All specimens were stored in water for 1 week at 37 degrees C and then thermocycled (1000 cycles, 5 degrees C to 55 degrees C, 30 seconds). The shear bond strength values were measured on a universal testing machine at a crosshead speed of 1 mm/min. Brackets treated with silica coating with silanization had significantly greater bond strength values (13.6 MPa, P =.01) than brackets treated with orthophosphoric acid (8.5 MPa). There was no significant difference (P =.97) between the bond strengths obtained after airborne abrasion with aluminium trioxide particles followed by silanization (12 MPa) and hydrofluoric acid application (11.2 MPa) (ANOVA and Tukey test). Although brackets conditioned with orthophosphoric acid exhibited only adhesive failures of the luting cement from the ceramic surface, other conditioning methods showed mixed types of failures. Airborne particle abrasion with aluminium trioxide or silica coating followed by silanization gave the most favorable bond strengths. The types of failures observed after debonding indicated that the critical parameter was the strength of the adhesive joint of the luting cement to both the bracket and the ceramic.     

Effects of ceramic surface treatments on the bond strength of an adhesive luting agent to CAD-CAM ceramic

OBJECTIVES: The objective of this study was to evaluate the effect of different surface treatments on the micro-tensile bond strength (microTBS) of an adhesive luting agent to CAD-CAM ceramic. The hypothesis tested was that neither of the surface treatments would produce higher bond strength of the adhesive luting agent to CAD-CAM ceramic. METHODS: Ceramic specimens of two different sizes (6 mm x 8 mm x 3 mm; 13 mm x 8 mm x 4 mm) were fabricated from ProCAD ceramic blocs (Ivoclar-Vivadent) with a low-speed diamond saw. The ceramic blocks were divided into seven groups and submitted to the following surface treatments: group 1: no treatment; group 2: etching with 37% H(3)PO(4); group 3: etching with 37% H(3)PO(4)+silane; group 4: etching with 37% H(3)PO(4)+silane+adhesive resin; group 5: etching with 4.9% HF acid; group 6: etching with 4.9% HF acid+silane; group 7: etching with HF acid+silane+adhesive resin. After surface treatment, two differently sized porcelain disks were bonded together with a composite luting agent (Variolink II, Ivoclar-Vivadent). The specimens were stored for 24h in distilled water at 37 degrees C prior to microTBS testing. One-way analysis of variance was used to test the influence of surface treatment and Scheffe multiple comparisons test determined pair-wise statistical differences (p<0.05) in microTBS between the experimental groups. RESULTS: The mean microTBSs (standard deviation) are: group 1: 12.8 (+/-4.6)MPa; group 2: 19.1 (+/-5.0)MPa; group 3: 27.4 (+/-11.1)MPa; group 4: 34.0 (+/-8.9)MPa; group 5: 37.6 (+/-8.4) MPa; group 6: 34.6 (+/-12.8)MPa; group 7: 34.5 (+/-5.1)MPa. Statistical significant differences were found between group 1 and groups 3-7, and between group 2 and groups 4-7. All specimens of groups 1-4 exhibited adhesive failures, while a combination of adhesive and mixed (adhesive and cohesive) failures was observed in the specimens of groups 5-7. CONCLUSIONS: The results show that surface treatment is important to bond to ceramic and suggests that etching is needed preferably with hydrofluoric acid than with phosphoric acid.     

Shear bond strength of a new resin bonding system to different ceramic restorations

This study evaluated the shear bond strength of a newly developed resin bonding system, including single-liquid ceramic primer and dual-cured resin luting agent, to 5 ceramic materials (feldspathic porcelain, machinable ceramic, In-Ceram Alumina, Procera AllCeram alumina, and Cercon). Ceramic specimens were cleaned with phosphoric acid, treated with primer, and bonded with a resin luting agent. Shear bond strength was determined after 24 hours of immersion in water and/or 10,000 thermocycles. There were no significant differences in bond strength before and after thermocycling for the 5 ceramic materials (P > .05). The findings indicate that the resin bonding system may offer an acceptable performance in terms of clinical success for the 5 ceramic restorations.     

Effect of ceramic surface treatment on tensile bond strength to a resin cement

PURPOSE: The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-to-resin systems. MATERIALS AND METHODS: Ceramic specimens were polished with 1-micron alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mode of failure. RESULTS: Silane-treated surfaces showed statistically higher mean tensile bond strength values than surfaces treated with any etchant (HF, ABF, APF). HF produced statistically higher mean tensile bond strengths than ABF and APF. All failures occurred in the adhesion zone. CONCLUSION: The tensile bond strength test is adequate for analysis of the adhesive zone of resin-ceramic systems. The chemical adhesion produced by silane promoted higher mean bond strength values than the micromechanical retention produced by any etchant for the resin-ceramic systems used in this study.     

Bonding of titanium with acidic primers and a tri-n-butylborane-initiated luting agent

summary Adhesive bonding of titanium was investigated with the use of five primers and two luting agents. All of the primers contained acidic methacrylate monomers for promotion of metal bonding. Titanium metal specimens were bonded with seven combinations of five primers and two luting agents. Durability of the bond was evaluated by means of thermocycling. Although all five primers enhanced the bond strength to titanium, three of the primers (Super-Bond Liquid, Metal Primer and Tokuso Rebase MR. Bond) demonstrated more durable bonds than the other two primers (Acryl Bond and All-Bond 2 Primer B). The tri- n -butylborane (TBB)-initiated luting agent exhibited better bonding ability as compared to conventional composite resin. The strongest and the most consistent bond was achieved by the combination of 4-methacryloyloxyethyl trimellitate anhydride (4-META) primer and TBB resin.     

3类修复体经3种瓷表面处理后与陶瓷托槽的粘结强度及去托槽后的瓷表面情况

目的研究3种瓷表面处理方法对3类修复体与陶瓷托槽粘结强度的影响以及去除托槽后瓷表面的情况。方法钴铬烤瓷、e-max铸瓷、二氧化锆全瓷3类修复体试件各36个,每类试件随机分为4组。除对照组为6个试件,其余各组每组10个试件。对照组不作任何处理。喷砂组,氧化铝喷砂4 s,冲洗、吹干后表面涂布硅烷偶联剂。磷酸组,质量分数37%磷酸酸蚀1 min,冲洗、吹干后表面涂布硅烷偶联剂。氢氟酸组,氢氟酸酸蚀2 min,冲洗、吹干后表面涂布硅烷偶联剂。使用光固化托槽粘结剂粘结陶瓷托槽。经37℃恒温水浴24 h后检测抗剪强度。观察托槽去除后瓷表面粘结剂残留情况和瓷面破损情况。结果 3种表面处理方法均能达到或超过有效粘结强度。采用喷砂并涂布硅烷偶联剂方法和氢氟酸酸蚀并涂布硅烷偶联剂方法,钴铬烤瓷试件的抗剪强度与e-max铸瓷和二氧化锆全瓷试件比较差异有统计学意义(P<0.05);磷酸酸蚀并涂布硅烷偶联剂方法中,3类修复体的抗剪强度差异无统计学意义(P>0.05)。3类修复体在使用氢氟酸并硅烷偶联剂处理后,抗剪强度较其他2种方法高,差异有统计学意义(P<0.05)。磷酸组的3类修复体瓷表面粘结剂残留指数得分最低,粘接剂残留最少,且瓷表面破坏最小。结论喷砂、磷酸酸蚀、氢氟酸酸蚀合并使用硅烷偶联剂处理钴铬烤瓷、e-max铸瓷、二氧化锆全瓷修复体,均能得到满意的粘结强度,而磷酸结合硅烷偶联剂方法去除托槽后对修复体表面的影响最小。     

Tensile bond strength of 4-META/MMA-TBB resin to ground bovine enamel using a self-etching primer

The purpose of this study was to examine the effectiveness of self-etching primer in adhering 4-META/MMA-TBB resin to bovine enamel. In this study, we designed an original self-etching primer which contained an aqueous mixture of 4-MET, 35 wt% HEMA, and ferric chloride. The polished bovine enamel surface was treated with self-etching primer for 30 seconds. Tensile bond strength of 4-META/MMA-TBB resin to enamel was measured after 1-day immersion in water at 37 degrees C. The self-etching primer containing 30 wt% 4-MET and 35 wt% HEMA (4MET30) gave a significantly higher bond strength of 11.2+/-2.8 MPa than other self-etching primers. The addition of ferric chloride into 4MET30 primer significantly decreased tensile bond strength. SEM observation revealed that 4MET30 treatment produced no distinct dissolution on enamel. When compared with phosphoric acid etching, the self-etching primer containing 30 wt% 4-MET and 35 wt% HEMA was more superior in adhering 4-META/MMA-TBB resin to enamel.     

Bond durability of the resin-bonded and silane treated ceramic surface.

OBJECTIVES: The aim of this study was to explore methods for improving the ceramic-silane-resin bond strength of silica-based ceramics, such that it may be possible to eliminate the hazardous process of acid etching these dental ceramics with hydrofluoric acid (HF). METHODS: Ni/Cr rods were prepared with ceramic facings, which were polished to a 1 microm finish. A silane coupling agent was applied to the ceramic surface using seven different procedures. Specimens were bonded using a luting resin and the tensile bond strength was measured at a crosshead speed of 1mm/min. One bonding procedure was selected and used for the comparison of four ceramic surface preparations consisting of; 1 microm polish, gritblasted (50 microm alumina), etched with 10% HF, and gritblasted and etched. The durability of the bond was assessed by (1) storing the specimens in water at 37 degrees C for different time periods up to 3 months, (2) thermal cycling, and (3) storing in water at 100 degrees C for 24h. RESULTS: The results showed that one bonding procedure to a polished ceramic surface gave better results for the tensile bond strength of the resin to the smooth ceramic surface and that the tensile bond strength was not significantly different from the gritblasted, etched or gritblasted and etched groups (P>0.05). There was no deterioration in the tensile bond strength for any of the groups after water storage for up to 3 months or after thermal cycling (P>0.05). The silane bond was also capable of resisting hydrolytic attack in boiling water. SIGNIFICANCE: The results indicate that a durable resin-ceramic tensile bond can be obtained by appropriate silane application without the need for HF acid etching the ceramic surface.     

纳米硅涂层对玻璃渗透氧化铝陶瓷粘结强度的影响

目的：探讨利用溶胶凝胶法进行纳米硅涂层表面改性对玻璃渗透氧化铝陶瓷粘结强度的影响。方法：3组In-Ceram氧化铝瓷块分别施以“喷砂（P组）”、“喷砂＋硅烷偶联（PO组）”、“喷砂＋纳米硅涂层＋硅烷偶联（PTO）组）”的表面处理。制作陶瓷／复合树脂粘结体,室温下置蒸馏水中浸泡24h,微拉伸法测试各组试件粘结强度。结果：P组与PO组粘结强度较弱且无明显差异（P=0．797）,PTO组的粘结强度明显高于其他组（P〈0．05）。结论：通过溶胶凝胶法在喷砂表面制备纳米硅涂层后应用硅烷偶联剂可以显著提高In-Ceram氧化铝陶瓷的粘结强度。     

Effects of primer containing silane and thiophosphate monomers on bonding resin to a leucite-reinforced ceramic

Objectives

Silane primers are commonly used for bonding between resin-based luting agents and ceramic restorations. The purpose of the present study was to evaluate the effects of nine silane primers on the bond strength of resin to a leucite-reinforced ceramic.

Methods

The commercially available dental primers used were five silane primers (GC Ceramic Primer, GP; Clearfil Ceramic Primer, CP; Tokuso Ceramic Primer, TP; Porcelain Liner M, PM; and Monobond Plus, MB). Four experimental primers (MDS, MTS, MDS/MPII, and MTS/MPII) and two control primers (MMA and MMA/MPII) were also prepared. The ceramic specimen was ground with silicon carbide paper, primed, and then bonded to a resin composite disc using a dual-curing luting agent. After a 24-h immersion in water, the shear bond strengths were determined.

Results

Shear bond testing revealed that the bond strength was significantly improved with the use of a MTS/MPII primer when compared to MDS, MTS, MMA, MDS/MPII and MMA/MPII. Although no significant differences were detected between GP, CP, PM, and MB, the primers CP, TP, PM, and MTS/MPII exhibited the highest bond strengths, followed by GP and MB, whilst the no-primer control resulted in the lowest values.

Conclusion

The maximum bond strengths were obtained with CP, TP, PM, and MTS/MPII. It was suggested that the thiophosphate monomer accelerated the role of the silane monomer. When selecting a primer to bond ceramic restorations, clinicians should be aware that not only the silane monomer but also additional components of the primer considerably affect the bond strength.     

In vitro evaluation of long-term bonding of Procera AllCeram alumina restorations with a modified resin luting agent

STATEMENT OF PROBLEM: Bonded densely sintered aluminum oxide ceramic restorations such as Procera AllCeram laminates rely on a strong and long-term durable resin bond. Air particle abrasion and a phosphate-modified resin luting agent have the potential to provide such bonds to aluminum oxide ceramics, but their efficacy on the Procera AllCeram intaglio surface is unknown. The inherent microroughness of this surface may influence bond strengths, because micromechanical interlocking is a main contributor for adhesion of resins to ceramic materials. PURPOSE: This study evaluated the bond strength of a phosphate-modified resin luting agent with and without silanization to an air particle-abraded Procera AllCeram intaglio surface compared with a conventional resin-bonding system before and after artificial aging. MATERIAL AND METHODS: Sixty square (10 x 10 x 2 mm) specimens of Procera AllCeram alumina ceramic with the Procera intaglio surface were air particle abraded with aluminum oxide. Composite cylinders (2.9 mm in diameter and 3.0 mm in width) were fabricated with Z-250 composite and bonded to the ceramic specimens with either Panavia 21 TC or Rely X ARC (control) and their corresponding bonding/silane coupling agents. In addition, Panavia was used without silanization as suggested in similar studies. Subgroups of 10 specimens were stored in distilled water for either 3 or 180 days before shear bond strength was tested with a universal testing machine (MPa) until fracture. The 180-day specimens were subjected to thermocycling at 2000 cycles every 30 days (12,000 cycles total). Data were analyzed with 1-way analysis of variance and Tukey's multiple comparison (alpha=.05). Failure modes were examined with a light microscope (original magnification x 25). RESULTS: Differences between short-term and long-term groups were highly significant (P=.000). Bond strength with Rely X ARC and its silane coupling agent (22.75 +/- 4 MPa) decreased significantly (P=.000) after artificial aging (3.32 +/- 3.62 MPa). Panavia 21 after silanization revealed significantly different (P=.003) early (21.42 +/- 4.3 MPa) and late (16.09 +/- 2.37 MPa) bond strengths but achieved the highest bond strength after artificial aging. Bond strengths of Panavia without silanization both early (8.06 +/- 2.1 MPa) and late (6.91 +/- 2.49 MPa) were not significantly different. Failure modes were mainly adhesive at the ceramic surface for all groups. CONCLUSION: Panavia 21 in combination with its corresponding bonding/silane coupling agent can achieve an acceptable resin bond to the air particle-abraded intaglio surface of Procera AllCeram restorations after artificial aging, which had mixed effects on the other investigated groups. The conventional resin luting agent revealed the most dramatic decrease in bond strength.     

Effects of two silane coupling agents, a bonding agent, and thermal cycling on the bond strength of a CAD/CAM composite material cemented with two resin luting agents

STATEMENT OF PROBLEM: Surface treatment of CAD/CAM-generated composite material is important for a strong bond of resin luting agents to composite material. Purpose. This study evaluated the shear bond strengths of 2 dual-cured resin luting agents to a CAD/CAM composite material and the effect of silane coupling agent and bonding resin on the bond strength. MATERIAL AND METHODS: Rectangular- and disk-shaped CAD/CAM composite materials were untreated or treated with 1 of the 2 silane coupling agents or bonding resin and then cemented together with 1 of the 2 dual-cured resin luting agents. Half of the specimens were stored in water at 37 degrees C for 24 hours, the other half thermocycled 50,000 times before shear bond strength testing. Shear bond strengths were measured with a servohydraulic mechanical testing machine, and results were analyzed with 2-way analysis of variance. RESULTS: Surface treatment by silane coupling agent improved the shear bond strength when compared with nontreatment. Specimens treated with bonding resin showed significantly greater shear bond strength than the untreated groups. However, all specimens had the same adhesive failures at the composite-luting agent interface as untreated groups. When the CAD/CAM composite material was treated with 1 of the 2 silane coupling agents, no significant differences in bond strength were noted between water storage alone and after 50,000 thermocycles. For the 2 groups treated with bonding resin or silane coupling agent and cemented with 1 of the 2 dual-cured resin luting agents, there were significant increases in bond strength after 50,000 thermocycles, compared with specimens that were not subjected to thermal cycling. On the other hand, for the 2 untreated groups, there were significant decreases in bond strength after thermocycling. After 50,000 thermocycles, all specimens treated with silane coupling agent and then cemented with 1 of the 2 resin luting agents showed cohesive failures within the composite material. CONCLUSION: The application of a silane coupling agent to the CAD/CAM composite surface provided the highest bond strength between the resin luting agent and composite after long-term thermal cycling.