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.     

The effect of silica coating on the resin bond to the intaglio surface of Procera AllCeram restorations.

OBJECTIVES: This study investigated the influence of a silica-coating method on the resin bond of two different resin composite cements to the intaglio surface of Procera AllCeram densely sintered, high-purity, alumina ceramic restorations after long-term storage and thermocycling. METHOD AND MATERIALS: Densely sintered alumina ceramic specimens were fabricated with the intaglio surface of the Procera AlICeram coping and randomly divided into five adhesive groups (100 total specimens). Resin composite cylinders were bonded either to the untreated or to the tribochemical silica/silane-coated ceramic surface with either a conventional Bis-GMA resin cement or a resin composite containing an adhesive phosphate monomer (Panavia 21) in combination with their corresponding bonding/silane coupling agents. Panavia was also used without silanization to the untreated ceramic surface (control). Subgroups of 10 specimens were stored in distilled water for either 3 (baseline) or 180 days prior to shear bond strength testing. The 180-day samples were subjected to repeated thermocycling for a total of 12,000 cycles. Data were analyzed with one-way analysis of variance and Tukey's multiple comparison. RESULTS: Silica coating significantly increased overall bond strength to Procera AllCeram. RelyX ARC and silica coating revealed the highest bond strength at baseline. Long-term storage and thermocycling significantly decreased overall bond strength. Two groups revealed the significantly highest bond strength values after artificial aging: Panavia 21 with its silane/bonding agent to the original ceramic surface and Panavia 21 to the silica-coated ceramic surface. CONCLUSION: The use of a resin composite containing an adhesive phosphate monomer either in combination with a silane coupling/bonding agent or after tribochemical silica/silane coating revealed the highest long-term shear bond strength to the intaglio surface of Procera AllCeram restorations.     

Tensile bond strength of four resin luting agents bonded to bovine enamel and dentin

STATEMENT OF PROBLEM: The resistance to fracture of ceramic restorations depends on adequate bonding to tooth structure. The dental substrate and the types of resin luting agents used are believed to produce variability in adhesive properties. PURPOSE: The purpose of this study was to evaluate the tensile bond strength of 4 resin luting agents to bovine enamel and dentin. MATERIAL AND METHODS: Forty bovine incisors were embedded in acrylic resin and ground horizontally with water-cooled silicon carbide paper to expose enamel (20 teeth) and dentin at the enamel/dentin junction (20 teeth). Ten standard cone-shaped specimens with a 3-mm diameter base were prepared for each of the following resin cements: Resin Cement, Rely X ARC, Nexus, and Enforce. Five specimens of each material were bonded to enamel and the other 5 to dentin with these resin luting agents and their respective adhesive systems, according to the manufacturers' directions. After 7 days of storage in distilled water at 37 degrees C, specimens were subjected to tensile forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Bond strength data were analyzed with analysis of variance for substrate and material. Means were compared with Tukey's test at the 0.05 level of significance. RESULTS: Analysis of variance disclosed that both substrate (P<.001) and material (P<.05) demonstrated statistically significant differences, but their interaction was not significant. The bond strengths (MPa) obtained for Resin Cement (11.5 +/- 3.0), Rely X ARC (11.4 +/- 3.1), Nexus (10.0 +/- 1.4), and Enforce (11.8 +/- 2.8) were statistically the same for enamel. For dentin, bond strengths (MPa) for Rely X ARC (9.6 +/- 1.8), Resin Cement (9.3 +/- 0.9), and Enforce (7.8 +/- 2.9) were significantly higher than for Nexus (3.5 +/- 0.8). Significantly higher bond strengths (MPa) were also observed for enamel (11.2 +/- 2.5) than dentin (7.5 +/- 1.6). CONCLUSION: Within the limitations of this study, tensile bond strengths of resin luting agents to enamel were higher than those to dentin, and the bond strength values of Nexus to dentin were significantly lower (P<.05) than the other cements tested.     

Effect of zirconium-oxide ceramic surface treatments on the bond strength to adhesive resin

STATEMENT OF PROBLEM: Surface treatment methods used for resin bonding to conventional silica-based dental ceramics are not reliable for zirconium-oxide ceramics. PURPOSE: The aim of this study was to compare the effects of airborne-particle abrasion, silanization, tribochemical silica coating, and a combination of bonding/silane coupling agent surface treatment methods on the bond strength of zirconium-oxide ceramic to a resin luting agent. MATERIAL AND METHODS: Sixty square-shaped (5 x 5 x 1.5 mm) zirconium-oxide ceramic (Cercon) specimens and composite resin (Z-250) cylinders (3 x 3 mm) were prepared. The ceramic surfaces were airborne-particle abraded with 125-microm aluminum-oxide (Al(2)O(3)) particles and then divided into 6 groups (n = 10) that were subsequently treated as follows: Group C, no treatment (control); Group SIL, silanized with a silane coupling agent (Clearfil Porcelain Bond Activator); Group BSIL, application of the adhesive 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP)-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/ Porcelain Bond Activator); Group SC, silica coating using 30-microm Al(2)O(3) particles modified by silica (CoJet System); Group SCSIL, silica coating and silanization (CoJet System); and Group SCBSIL, silica coating and application of an MDP-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/Porcelain Bond Activator). The composite resin cylinders were bonded to the treated ceramic surfaces using an adhesive phosphate monomer-containing resin luting agent (Panavia F). After the specimens were stored in distilled water at 37 degrees C for 24 hours, their shear bonding strength was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. Debonded specimen surfaces were examined with a stereomicroscope to assess the mode of failure, and the treated surfaces were observed by scanning electron microscopy. Bond strength data were analyzed using 1-way analysis of variance and the Duncan test (alpha = .05). RESULTS: The bond strengths (mean +/- SD; MPa) in the groups were as follows: Group C, 15.7 +/- 2.9; Group SIL, 16.5 +/- 3.4; Group BSIL, 18.8 +/- 2.8; Group SC, 21.6 +/- 3.6; Group SCSIL, 21.9 +/- 3.9; and Group SCBSIL, 22.9 +/- 3.1. The bond strength was significantly higher in Group SCBSIL than in Groups C, SIL, and BSIL (P<.001), but did not differ significantly from those in Groups SC and SCSIL. Failure modes were primarily adhesive at the interface between zirconium and the resin luting agent in Groups C and SIL, and primarily mixed and cohesive in Groups SC, SCSIL, and SCBSIL. CONCLUSION: Tribochemical silica coating (CoJet System) and the application of an MDP-containing bonding/silane coupling agent mixture increased the shear bond strength between zirconium-oxide ceramic and resin luting agent (Panavia F).     

Bonding to densely sintered alumina surfaces: effect of sandblasting and silica coating on shear bond strength of luting cements

PURPOSE: An important determinant of the clinical success of ceramic restorations is the bond strength of the luting agent to the seating surface and the prepared tooth structures. Manufacturers of ceramic systems frequently specify both the luting agent and preluting treatment of the seating surface of the crown. Procera AllCeram is an all-ceramic crown comprising a porcelain-veneered coping of densely sintered, high-purity aluminum oxide. This study evaluated the shear bond strength of 4 luting agents: zinc-phosphate, glass-ionomer, resin-modified glass-ionomer, and resin cement (dual cured) to Procera aluminum oxide coping material. The luting agents were subjected to different surface treatments: untreated, sandblasted, or silica coated by the Rocatec system. MATERIALS AND METHODS: Cylindric and cubic specimens of the coping material were luted together, and the shear force necessary to separate the cylinder from the cube was measured with a universal testing machine. The surfaces of the specimens were also analyzed. RESULTS: No significant differences were recorded for the shear bond strengths of the luting agents to the untreated aluminum oxide. Glass-ionomer and the resin-modified glass-ionomer cements had the highest values (4.2 +/- 2.5 MPa and 4.3 +/- 1.9 MPa, respectively), and the lowest were 3.3 +/- 2.3 MPa for the resin cement and 3.2 +/- 1.0 MPa for the zinc-phosphate cement. Similar results were recorded for the sandblasted aluminum oxide surfaces, except with the glass-ionomer, which was significantly higher (12.9 +/- 2.4 MPa). For all 4 luting agents, the highest shear bond strength values were recorded for the silica-coated specimens; the highest was for the resin cement, at 36.2 +/- 7.8 MPa. CONCLUSION: The bond strengths between resin cement and aluminum oxide specimens treated by the Rocatec system were significantly higher than those of the other materials and surface treatments evaluated.     

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.     

Durability of the resin bond strength to the alumina ceramic Procera.

OBJECTIVES: The purpose of this in vitro study was to evaluate the tensile bond strength of adhesive bonding systems to the densely sintered alumina ceramic Procera, and its durability. METHODS: Plexiglas tubes filled with composite resin were bonded to Procera ceramic discs (99% Al2O3), which were either in their original state as supplied by the manufacturer or which were sandblasted for surface conditioning. Groups of 20 specimens were bonded in an alignment apparatus using 10 bonding methods. Subgroups of 10 bonded specimens were tested for tensile strength following storage in distilled water at 37 degrees C either for 3 days or for 150 days. In addition, the 150 days specimens were thermal cycled 37,500 times. The statistical analyses were conducted with the Kruskal-Wallis test followed by multiple pair-wise comparison of groups using the Wilcoxon rank sum test. RESULTS: Not sandblasted groups showed relatively poor initial bond strengths independent from bonding resins. During 150 days storage time all specimens in the not sandblasted groups debonded spontaneously. Moderate to relatively high initial bond strengths between 18 and 39 MPa were achieved to sandblasted specimens by using the PMMA luting resin Superbond C & B or the composite resin Variolink II or by silica coating and silanation in combination with Variolink II. However, in these groups after 150 days storage time the bond strength decreased significantly. The phosphate monomer containing composite resin Panavia 21 showed the highest bond strength to sandblasted Procera ceramic which did not decrease significantly over storage time. In addition, the bond strengths of sandblasted groups bonded with Variolink II after priming the ceramic with Alloy Primer or the silane Monobond S were relatively high and did also not decrease significantly after 150 days storage time. SIGNIFICANCE: Using ten bonding systems, a stable resin bond to Procera ceramic could be achieved after sandblasting and by using Panavia 21 or by using Variolink II after priming the ceramic with Alloy Primer or Monobond S.     

Effect of three-liquid bonding agents on bond strength to a machine milled ceramic material

This study determined the bond strengths of porcelain bonding systems joined to a ceramic material, with the aim of evaluating the effect of a catalyst for silane coupling as well as that of initiators for bonding agents. Two sizes of specimen were cut from ceramic blocks (Cerec 2 Vitablocs Mark II) and then primed with either a three-liquid self-curing bonding agent (Clearfil Porcelain Bond, CPB), a three-liquid dual-activated bonding agent (Clapearl Bonding Agent, CBA), or their components. Unprimed specimens were also used as controls. After conditioning, the two different sized plates were bonded together with a dual-cured luting agent (Clapearl DC). The specimens were stored in 37 degrees C water for 24 h and shear bond strengths were determined. Shear testing revealed that the greatest bond strength was generated in the group consisting of ceramic material primed with CBA and exposed for 20 s prior to luting. Bond strengths of the CPB-primed group and the CBA-primed group without pre-exposure were comparable, whereas the remaining groups resulted in significantly lower bond strengths than the other three groups. The priming effect was greatly enhanced when a catalyst was used with the silane coupler as compared with the application of silane alone. The results suggest that incorporation of an initiator and a catalyst for silane coupling into the bonding agent reciprocally enhances bonding between the luting agent and the ceramic material.     

Shear bond strength of resin cements to both ceramic and dentin

STATEMENT OF PROBLEM: All ceramic restorations benefit from resin cement bonding to the tooth. However, the literature is unclear on which cement, ceramic conditioning treatment, and dentin bonding agent produce the highest and longest-lasting bond strength. PURPOSE: This in vitro study evaluated immediate and 6-month shear bond strengths between a feldspathic ceramic and 4 different resin cements with the use of 6 different surface-conditioning treatments. Shear bond strengths between the 4 resin cements and dentin also were measured. MATERIAL AND METHODS: Four hundred eighty discs (10 mm in diameter and 4 mm thick) of Ceramco II porcelain were randomly divided into 6 main groups (n = 80). The ceramic specimens received 6 different surface conditioning treatments before the application of resin cement. These surface treatments were sanding with 600-grit silicon carbide paper, microetching with aluminum oxide, sanding followed by silane application, microetching followed by silane application, hydrofluoric acid-etching, and hydrofluoric acid-etching followed by silane application. Each group then was subdivided into 4 subgroups (n = 20) for the application of 1 of 4 cements: Nexus, Panavia 21, RelyX ARC, and Calibra. All cemented specimens were tested under shear loading until fracture on a universal testing machine; the load at fracture was reported in MPa as the bond strength. Bond strengths were determined at 24 hours and after 6 months of specimen storage in a saline solution. For dentin-resin cement shear bond strength testing, dentin specimens were treated with dentin bonding agents, and a thin layer of resin cement was applied according to the manufacturer's directions. Prodigy composite was bonded to the cement. Shear bond strengths were determined as above and reported in MPa at fracture. Data were analyzed with 3-way analysis of variance (P<.01). RESULTS: Hydrofluoric acid-etching followed by silane application produced bond strengths (15.0 +/- 7.4 to 21.8 +/- 5.8 MPa) in the highest statistical group with all 4 cements at both 24 hours and 6 months (P<.01). Sanding with 600-grit silicon carbide paper and microetching with aluminum oxide produced the lowest bond strengths (0.0 to 4.0 +/- 3.5 MPa). At 24 hours and 6 months, there were no significant differences among the 4 cements when hydrofluoric acid-etching was followed by silane application. Both auto- and light-polymerized dentin bonding agents bonded better to dentin than dual-polymerized bonding agents. CONCLUSION: Within the limitations of this study, hydrofluoric acid-etching followed by silane application produced the best bonds at 24 hours and 6 months with all 4 cements. Auto- and light-polymerized adhesives were associated with higher bond strengths to dentin than dual-polymerized adhesives.     

Evaluation of five dental silanes on bonding a luting cement onto silica-coated titanium

OBJECTIVES: Five commercial dental silanes were evaluated in vitro as adhesion promoters bonding a luting cement to silica-coated titanium surfaces. METHODS: Titanium slides (n=20) were cleaned with alumina sand and then silica-coated with a special sand consisting of alumina particles coated with silica. The bonding of a resin composite cement (3M ESPE, Seefeld, Germany) to silica-coated and silanized titanium was evaluated by using the dental silane (RelyX Ceramic Primer) that belongs to the RelyX ARC cementing kit, and comparing it to four other dental silanes (Bisco Porcelain Primer, Cimara, ESPE Sil, and Pulpdent Silane Bond Enhancer). The resin composite cement stubs (n=8) were light-polymerized onto a silanized silica-coated titanium surface. The shear bond strength of the cement stubs was measured after dry storage and thermo-cycling 6000 times between 5 and 55 degrees C. The silanes and their reactions were chemically monitored by using Fourier transform infrared analysis. RESULTS: Statistical analysis using ANOVA revealed that the brand of silanes and the types of storage condition differ significantly (p<0.005). The highest shear bond strength was obtained with RelyX ceramic silane in dry conditions (19.5+/-4.3 MPa), and after thermo-cycling (16.6+/-3.5 MPa). The lowest results were obtained using Pulpdent Silane Bond Enhancer, in dry conditions (7.8+/-2.2 MPa), and after thermocycling (5.3+/-2.4 MPa). The analysis showed that silanes had different pH values. Some differences were detected between the silanes and their reactions. CONCLUSIONS: Dental silanes provide different bonding strengths and have differences in their pH, solvent system and silane concentration.     

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.     

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.     

Influence of ceramic thickness and polymerization mode of a resin luting agent on early bond strength and durability with a lithium disilicate-based ceramic system

STATEMENT OF PROBLEM: Attenuation of polymerization light energy by translucent all-ceramic materials may result in insufficient polymerization of underlying resin luting agents and inadequate early bond strength and durability. There is little information regarding the selection of an appropriate polymerization mode for cementing translucent all-ceramic restorations. PURPOSE: The purpose of this study was to evaluate the influence of ceramic thickness and polymerization mode on the early bond strength and bond durability of a lithium disilicate-based ceramic system. MATERIAL AND METHODS: The occlusal surfaces of 120 extracted, intact, human third molars were sectioned to expose a flattened area of dentin. The surface was etched with 32% phosphoric acid, and a single-step adhesive (One-Step) was applied to the etched dentin surfaces. Ceramic specimens (Empress 2), 6 mm in diameter and 1 mm, 1.5 mm, or 2 mm thick (n=40 per group), were fabricated using fluoropolymer resin matrixes. Each specimen was ground flat. Following hydrofluoric acid etching and silane treatment, ceramic discs of each thickness were further divided into 2 groups (n=20 per group) and bonded to the dentin surfaces with a dual-polymerized resin luting agent (Illusion), either with a catalyst (dual polymerization) or without a catalyst (light polymerization). A shear bond test was performed after 10 minutes (n=10) or after 24 hours following 1000 thermal cycles between 5 degrees C and 55 degrees C and a dwell time of 30 seconds (n=10). Debonded dentin surfaces were examined with SEM. The data were analyzed with 3-way analysis of variance (ANOVA) (alpha=.05). RESULTS: The shear bond strengths ranged between 13.2 +/- 4.1 MPa and 15.9 +/- 2.0 MPa. Three-way ANOVA revealed that ceramic thickness, polymerization mode, storage time, or combinations of these parameters did not influence shear bond strength. The location of failure for all specimens was adhesive, between the dentin surface and bonding agent. CONCLUSION: Both light polymerization and dual polymerization provided similar early shear bond strengths for the lithium disilicate-based ceramic system (Empress 2). The bond strength was not dependent on the thickness of the ceramic material tested. Durability of the bond was similar for both of the polymerization modes.     

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.     

Effect of different bonding agents on shear bond strengths of composite-bonded porcelain to enamel

STATEMENT OF PROBLEM: The use of bonding agents in the luting procedure for porcelain laminate restorations to enamel is not clear. PURPOSE: This study evaluated the shear bond strength differences between an enamel-luting composite and a heat-pressed ceramic with 6 different bonding systems. MATERIAL AND METHODS: Seventy standardized heat-pressed IPS Empress ceramic discs (4-mm diameter, 3-mm height) were prepared. A vertical planar enamel-bonding surface was prepared on the buccal or lingual enamel of 70 freshly extracted sound human molars and premolars. The teeth were oriented to maintain a parallel relationship between the bonding plane and the shear loading axis of a universal testing machine. Tooth specimens were divided into 7 groups (n=10) comprising equal numbers of molars and premolars. The enamel surfaces of specimens in groups 1 through 6 were prepared with 1 of 6 bonding agents (Scotchbond Multi Purpose Plus, Heliobond, PQ1, SE Bond, Prime&Bond NT, and Prompt L-Pop). Finally, the specimens were luted to the ceramic discs with the composite cement (Opal Luting Composite). Ceramic discs in the seventh group (Control) were luted to the etched enamel with the composite cement without using bonding material. Enamel-ceramic specimens were kept in distilled water at room temperature for 30 days after cementation. All specimens were shear loaded axially in a universal testing machine with a crosshead speed of 0.05 mm/min until fracture. Shear bond strength was measured and recorded for each group in MPa. To determine the statistical significance of the differences between the mean shear bond strength values, a 1-way analysis of variance was used (alpha=.05). Post-hoc multiple comparisons were made with Duncan's multiple range analysis. Fractured surfaces of each specimen were also inspected with a stereomicroscope to evaluate failure modes. RESULTS: A 1-way analysis of variance revealed significant differences between the test groups (P=.00). Bond strength values (MPa) from the highest to the lowest were as follows: Prompt L-Pop, 25.46 +/- 5.6; Prime&Bond NT, 18.99 +/- 4.93; Heliobond, 17.28 +/- 4.0; SE Bond, 16.21 +/- 2.6; PQ1, 15.60 +/- 2.8; Scotchbond MPP, 14.82 +/- 2.4; and Control, 10.55 +/- 1.6. Duncan's multiple range post hoc analysis exhibited significant differences between the control group and the adhesive bonding agent groups (P<.05). There were also significant differences between the bonding agent groups (P<.05). Prompt L-Pop showed the highest bond strength values. CONCLUSION: Within the limitations of this study, bonding agents appear to have a strengthening effect on the shear bond strengths of the enamel/composite/porcelain interface of the materials tested. Bonding agents used in this study showed similar bond strength values except for Prompt L-Pop, which demonstrated the highest bond strength values.     

Effects of adhesive liner and provisional cement on the bond strength of nickel/chrome/beryllium alloy cemented to dentin.

OBJECTIVE: Treating teeth with adhesive agents before placing a provisional restoration can prevent tooth sensitivity. This study evaluated the bond strength of resin cements to dentin treated with 2 adhesive agents and 2 provisional cements. METHODS AND MATERIALS: Extracted human molars were prepared by exposing dentin and were treated with either Prime & Bond NT or Clearfil SE Bond. After a simulated impression technique, the teeth were provisionalized with either a eugenol or noneugenol temporary cement. Teeth were cleaned for bonding by either mechanical removal of the cement or use of an acid conditioner. Panavia F and Calibra resin cements were used to cement nickel/chrome/beryllium alloy to the tooth surfaces, and the specimens were debonded. Mean shear bond strengths for each group were calculated. RESULTS: Mean shear bond strengths ranged from 26.6 +/- 5.8 MPa for Calibra bonded to dentin treated with Prime & Bond NT, a noneugenol cement, and mechanically cleaned, to 10.6 +/- 4.4 MPa for Panavia F bonded to unlined (no adhesive) dentin treated with a eugenol cement and mechanically cleaned. Of the 14 groups tested, significant differences were observed related to the adhesives and resin cements. Both temporary cements reduced the bond to dentin not treated with a resin adhesive. Use of an acid conditioner for cleaning the temporary cement also reduced bond strengths in all groups. CONCLUSIONS: Placement of a dentin adhesive before provisionalization may prevent the temporary cement from affecting the bond of the final resin cement to the tooth. For the products used in this study, use of phosphoric acid to clean the tooth surface is not recommended.     

Shear bond strength of two resin cements to human root dentin using three dentin bonding agents

This study compared the bond strength of two resin cements to human root dentin when used with three bonding agents. The materials used were Rely X ARC and Perma Cem, two one-bottle bonding agents (Single Bond, Bond-1) and one self-etching bonding agent (Clearfil SE Bond). The dentin was obtained from single rooted human teeth, and the specimens were treated with either 15% EDTA or 37% phosphoric acid to remove the smear layer, except in groups where the self-etching bonding agent was used. The resin cements were placed on dentin surfaces with the use of bonding agents. Shear bond strength (SBS) was tested using a single plane shear test assembly. The dentin specimens were divided into 10 groups. Eight groups were pre-treated with EDTA or phosphoric acid to remove the smear layer, followed by a bonding agent (Bond-1 or Single Bond) and resin cement (Rely X or Perma Cem). In the two remaining groups, the smear layer was left intact, and the two resins cements were used in combination with the self-etching bonding agent (Clearfil SE Bond). No statistically significant differences were observed among the eight groups treated with one-bottle bonding agents. The mean bond strengths of the two groups treated with the self-etching bonding agent did not differ significantly from each other but were both significantly greater than the bond strengths of all the other groups. The results of this study also showed that EDTA can be used as an alternative to phosphoric acid in bonding procedures for resin cements. However, the bond strengths of resin cements, in combination with a self-etching bonding agent, were significantly greater than those of the same cements when used with one-bottle bonding agents.     

Comparison of shear bond strength of three bonding agents with metal and ceramic brackets.

Shear bond strengths of a light-cured composite resin, a light-cured glass ionomer cement, and a light-cured compomer used with metal and ceramic brackets were compared, and ARI scores were evaluated. Ceramic brackets showed statistically higher shear bond strengths than metal brackets when bonded with all test materials (p<0.001). When used with metal brackets, the light-cured glass ionomer cement (LCGIC) and compomer materials demonstrated statistically lower shear bond strengths than the light-cured composite (p<0.01 and p<0.001, respectively). When used with ceramic brackets, LCGIC was found to have significantly lower shear bond strength than the composite material (p<0.001). Despite its relatively low shear bond strength, LCGIC demonstrated optimal bonding values (8.39+/-3.24 MPa) with ceramic brackets. Bond failures within the LCGIC groups occurred at the adhesive-tooth interface, whereas in the compomer and composite groups, failures were detected at the adhesive-bracket interface. In the metal bracket group, clinically acceptable shear bond strength was obtained only with the composite resin (7.06+/-1.65 MPa). Compomer and LCGIC demonstrated values well below the accepted standard for metal brackets (4.32+/-1.75 MPa and 4.45+/-1.06, respectively), while in the ceramic bracket group, values for composite and compomer were above the desired level (14.40+/-5.88 MPa and 12.31+/-6.09, respectively). LCGIC showed reasonably good bond strength with ceramic brackets, suggesting that this material may be considered suitable for use with ceramic brackets in clinical situations where moisture cannot be controlled.     

Effect of dentin primer on shear bond strength of composite resin to moist and dry enamel

The etched enamel-composite resin bond is the most reliable bond known to us. Moisture and dentin primers are the two most important variables that can interfere with this bond. This study investigated the effect of dentin primer on bond strengths of composite resin to moist and dry enamel. One hundred freshly extracted molar teeth were used for shear bond strength testing. The teeth were mounted in phenolic rings with an approximal enamel surface exposed. The exposed enamel surface on each tooth was flattened using 320- 400- and 600-grit silicon carbide papers and etched using 34-38% phosphoric acid gel. The teeth were then divided into 10 groups (n = 10). Four groups were assigned to each of the two dentin bonding systems, Scotchbond Multi-Purpose and OptiBond FL. Two groups were assigned to the single-bottle bonding agent (Single Bond). Each bonding system was tested on moist and dry enamel. OptiBond FL and Scotchbond MP were tested with and without the use of primer. All samples were thermocycled and tested in shear. Fracture analysis was performed using a binocular microscope. For scanning electron microscopy, approximal samples of enamel (1 mm thick) were flattened, etched, and bonded with and without primer on moist and dry enamel. A 1 mm-thick layer of Z100 was bonded to the specimens, which were then immersed in 10% HCl for 24 hours to dissolve the enamel. The specimens were viewed under a scanning electron microscope. Results indicated that the use of primer on dry enamel did not significantly affect (P > 0.05) shear bond strengths for the two bonding systems, Scotchbond MP (primed 24.10 +/- 4.83 MPa, unprimed 29.57 +/- 7.49 MPa) and OptiBond FL (primed 26.82 +/- 4.44, unprimed 25.66 +/- 2.95). However, the use of primer was found to be essential on moist enamel to obtain acceptable bond strengths with both Scotchbond MP (primed 25.61 +/- 10.29 MPa, unprimed 3.26 +/- 0.95 MPa) and OptiBond FL (primed 30.28 +/- 3.49 MPa, unprimed 8.37 +/- 3.31 MPa). Moisture on enamel did not significantly affect (P > 0.05) bond strengths for the single-bottle bonding agent, Single Bond (moist enamel 31.34 +/- 9.03 MPa, dry enamel 27.93 +/- 5.41 MPa). Fracture analysis revealed that most fractures were adhesive or mixed, with a greater percentage being cohesive for the groups with dry enamel or with primer on moist enamel. Scanning electron micrographs corroborated the shear bond strength data. The specimens without primer on moist enamel showed very poor penetration of adhesive and composite resin into the etched enamel microporosities.     

Shear bond strength between nickel-chromium and human dentine using a dual-cure, self-adhesive universal resin luting agent

The adhesive property of a dual-cure, self-adhesive universal resin luting agent (Rely X Unicem, 3M ESPE) between nickel-chromium (Ni-Cr) and human dentine was compared with three conventional resin luting agents (Calibra, Dentsply; Panavia-F, Kuraray; All-bond 2 C & B cement, Bisco). Ten Ni-Cr rods were bonded to human dentine with each of the four luting agents, and were subjected to shear bond test. Results showed that there was no significant difference in shear bond strengths among the luting agents. A dual-cure, self-adhesive universal resin luting agent was shown to have comparable adhesive property between Ni-Cr and human dentine as three other conventional resin luting agents. Given the simplicity of use of the dual-cure, self-adhesive universal resin luting agent, it appears to be promising in clinical applications.