Bond strength of composite luting cement to zirconia ceramic surfaces

OBJECTIVES: To evaluate the bond strength of dental resin agent to zirconia ceramic after surface pre-treatment with different techniques. METHODS: Specimens of hot isostatic pressed yttrium-oxide-partially-stabilized zirconia blocks (ZF) were fabricated (Procera Zircon, Nobel Biocare, Sweden) and compared to glossy dense zirconia blocks (ZG). Four groups of specimens with different surface treatment were prepared. Group I: ZF (n = 5) and ZG (n = 5) without any pre-treatment, Group II: ZF-s (n = 5) and ZG-s (n = 5) treated with silane solution, Group III: ZF-P (n = 10) and ZG-P (n = 10) treated with RF plasma spraying (hexamethyldisiloxane) using a reactor (Plasma Electronic, Germany), Group IV: ZF-p (n = 10) and ZG-p (n = 10) treated with micro pearls of low fusing porcelain (720 degrees C) on the surfaces. Composite cylinders (Charisma, Hereus Kulzer, Dormagen, Germany) were luted with Variolink II (Ivoclar-Vivadent, Schaan, Liechtenstein) to the test specimens. The specimens were then stored in air for 1 h before shear loading in a universal testing machine (LRX, Lloyd Instruments, Farnham, England) until failure. RESULTS: No statistical difference was found between the untreated ZF and ZG specimens (Group I) neither between the specimens treated with silane (Group II). Plasma spraying treatment improved bond strength by a factor of three (p < 0.001). Treatment with low fusing porcelain micro pearls increased the bond strength by a factor of 10 compared to untreated surfaces (p < 0.001). No significant difference was seen between the surfaces treated ZF-p and ZG-p specimens. The thickness of the glass pearls layer did not exceed 5 microm. SEM showed dense grain borders of ZF and a flat glossy texture of ZG. SIGNIFICANCE: Treatment of zirconia ceramic surfaces with plasma spraying or a low fusing porcelain pearl layer significantly increased the bond strength of resin cement to the ceramic surface.     

Bond strength of a composite resin to an adhesive luting cement

This study evaluated the influence of surface treatment on the shear bond strength of a composite resin (CR), previously submitted to the application of a temporary cement (TC), to an adhesive luting cement. Eight-four CR cylinders (5 mm diameter and 3 mm high) were fabricated and embedded in acrylic resin. The sets were divided into 6 groups (G1 to G6) (n=12). Groups 2 to 6 received a coat of TC. After 24 h, TC was removed and the CR surfaces received the following treatments: G2: ethanol; G3: rotary brush and pumice; G4: air-abrasion; G5: air-abrasion and adhesive system; G6: air-abrasion, acid etching and adhesive system. G1 (control) did not receive TC or any surface treatment. The sets were adapted to a matrix and received an increment of an adhesive luting cement. The specimens were subjected to the shear bond strength test. ANOVA and Tukey's tests showed that G3 (8.53 MPa) and G4 (8.63 MPa) differed significantly (p=0.001) from G1 (13.34 MPa). The highest mean shear bond strength values were found in G5 (14.78 MPa) and G6 (15.86 MPa). Air-abrasion of CR surface associated with an adhesive system provided an effective bond of the CR to the adhesive luting cement, regardless the pre-treatment with the phosphoric acid.     

Bond strength of a luting composite to dentin with different bonding systems

This study evaluated the tensile bond strength of Conclude luting composite to dentin under different environmental conditions with Scotchbond dental adhesive, the FNP system, and unfilled BIS-GMA resin used as bonding agents. Although the bonding systems reportedly yield high tensile bond values to enamel, large differences were observed in this study for bond values to dentin. Only the FNP bonding system produced consistently high tensile load values to dentin under the three environmental conditions tested.     

Bond strength of luting materials to ceramic crowns after different surface treatments

The aim of present study was to evaluate the effect of different pre-treatments of alumina and zirconia copings on the bond strength of different luting materials. Pull out tests was performed on 60 alumina and 80 zirconia copings. Randomly selected, copings were divided in groups of i) un-treated alumina and zirconia copings, (n=20) ii) alumina and zirconia copings sandblasted with 50 or 110 microm alumina particles respectively (n=20), iii) zirconia copings treated with monolayer of glass pearls fused to the inner surface (n=20), iv) zirconia copings treated with silanized glass pearls (n=10). Zinc phosphate, Panavia 21 and VarioLink II were used for cementation. Pull out tests were done in an Instron universal testing machine with a speed of 0.5 mm/min and fracture loads was measured in N. Untreated zirconia copings cemented with zinc phosphate showed significantly higher bond strength values compared to those with sandblasted surfaces. No difference was seen between untreated alumina copings and those with sandblasted surfaces. Sandblasting decreased bond strength of zirconia and alumina copings. Glass pearls increased bond strength of zirconia copings, which was even better after silanization. Variolink II in combination with alumina gave significantly lower bond strength.     

Bond durability of composite luting agents to ceramic when exposed to long-term thermocycling

PURPOSE: This study evaluated the effect of thermocycling on the microtensile bond strength of four adhesive luting agents to GN-I CAD-CAM ceramic. The hypothesis tested was that thermocycling did not affect bonding effectiveness, irrespective of the luting agents used. MATERIALS AND METHODS: Ceramic specimens of two different sizes (6x8x3 mm; 13x8x4 nm) were fabricated from GN-I CAD-CAM ceramic blocks (GC) using a low-speed diamond saw. Two different sized porcelain discs were bonded with one of the four composite luting agents (Linkmax [LM], Panavia [PN], RelyX Unicem [UN] and Variolink II [VL]) according to the manufacturer's instructions. The specimens were stored for 24 hours in distilled water at 37 degrees C and subjected to 0; 10,000; 20,000 and 40,000 thermocycles prior to microTBS testing. Two-way analysis of variance was used to test the influence of luting cement, thermocycling and interaction between both (p < 0.05). The Tukey HSD test determined statistical differences in microTBS for each luting composite between the different thermocycling conditions (p < 0.05). The mode of failure was determined at a magnification of 50x using a stereomicroscope (Wild M5A). RESULTS: Two-way ANOVA revealed that microtensile bond strength was affected by the luting cement, thermocycling and a combination of both. No difference in bond strength between Linkmax, Panavia F and Variolink II was noticed after 24 hours of water storage (LM: 47.6 MPa; PN: 41 MPa; VL: 36 MPa). RelyX Unicem scored significantly lower than Linkmax and Panavia F (UN: 24.2 MPa). The influence of thermocycling on bond strength was different for the four luting cements. Using Variolink II, the bond strength remained stable after 40,000 thermocycles (43.6 MPa). Linkmax showed a significant decrease in bond strength after 10,000 (26 MPa) and 40,000 thermocycles (14.8 MPa). Panavia F and RelyX Unicem were the most negatively influenced, as all specimens failed prior to testing (pre-testing failures) when the specimens were thermocycled 10,000 and 20,000 times or longer, respectively. Regarding the failure mode, there was a correlation between bond strength and type of failure. Initially, a combination of adhesive and mixed adhesive-cohesive failures was noticed. The percentage of adhesive failures increased, together with a decrease in bond strength. CONCLUSION: It was concluded that there were significant differences among the four resin composite cements in terms of their bonding effectiveness to CAD-CAM ceramic after thermocycling. The varying degrees of bonding effectiveness of these adhesive luting agents highlight the need for material specifications.     

Bond strength of selected composite resin-cements to zirconium-oxide ceramic

Objectives: The aim of this study was to evaluate bond strengths of zirconium-oxide (zirconia) ceramic and a selection of different composite resin cements. Study Design: 130 Lava TM cylinders were fabricated. The cylinders were sandblasted with 80 µm aluminium oxide or silica coated with CoJet Sand. Silane, and bonding agent and/or Clearfil Ceramic Primer were applied. One hundred thirty composite cement cylinders, comprising two dual-polymerizing (Variolink II and Panavia F) and two autopolymerizing (Rely X and Multilink) resins were bonded to the ceramic samples. A shear test was conducted, followed by an optical microscopy study to identify the location and type of failure, an electron microscopy study (SEM and TEM) and statistical analysis using the Kruskal-Wallis test for more than two independent samples and Mann-Whitney for two independent samples. Given the large number of combinations, Bonferroni correction was applied (α=0.001). Results: Dual-polymerizing cements provided better adhesion values (11.7 MPa) than the autopolymerizing (7.47 MPa) (p-value M-W<0.001). The worst techniques were Lava TM + sandblasting + Silane + Rely X; Lava TM + sandblasting + Silane + Multilink and Lava TM + CoJet + silane + Multilink. Adhesive failure (separation of cement and ceramic) was produced at a lesser force than cohesive failure (fracture of cement) (p-value M-W<0.001). Electron microscopy confirmed that the surface treatments modified the zirconium-oxide ceramic, creating a more rough and retentive surface, thus providing an improved micromechanical interlocking between the cement and the ceramic. Key words:Shear bond strength, silica coating, surface treatment, zirconia ceramics, phosphate monomer.     

The effect of surface preparation and luting agent on bond strength to a zirconium-based ceramic

OBJECTIVES: To investigate the bond strength of modern "self-adhesive" resin cements to a zirconium-based dental ceramic following different surface preparations and storage conditions. METHODS: The surface of zirconium-based ceramic discs (12 x 2 mm) were either left untreated, prepared using alumina grit-blasting or tribochemical treatment. Resin composite cylinders were bonded to ceramic specimens using Panavia-F, RelyX Unicem or Maxcem resin cements. The shear bond strength of specimens (n = 10) was tested "dry," following 24-hour water immersion or a thermocycling regime. RESULTS: For each surface preparation, a significant reduction in bond strength following 24-hour water immersion and thermocycling compared to "dry" storage conditions was identified for both Panavia-F and Maxcem. However, Unicem specimens exhibited statistically similar SBS values for tribochemically-treated specimens stored dry following 24-hour water immersion or thermocycling (11.7 +/- 1.3, 14.1 +/- 6.3 and 11.7 +/- 4.9 MPa, respectively) (p > 0.05). No significant differences in bond strength were identified for Panavia-F or Unicem specimens for any surface preparation following the thermocycling regime (p > 0.05). In contrast, for each surface preparation following thermocycling (p < 0.001), Maxcem exhibited a significant decrease in SBS compared with Panavia-F and Unicem specimens. CONCLUSIONS: The pre-treatment of a zirconium-based ceramic surface with grit-blasting and tribochemical treatment improves the bond strength of resin cements. Following "wet" storage conditions, Panavia-F and Unicem demonstrated superior bond strength compared with Maxcem. Differences in ceramic surface preparation and the chemistry of resin cements will affect the nature of the bonding mechanism and durability of the adhesive layer.     

Bond strength between luting materials and a fiber-reinforced resin composite for indirect restorations

The purpose of the present study was to evaluate the bond strength between a fiber-reinforced composite (FRC) and six luting agents (Panavia F 2.0, Linkmax MC, Chemiace II, Multibond, Super-Bond C&B, and Fuji I). A prosthodontic resin composite material (RC-control) and a luting agent containing no functional monomer (MT) were used as controls. Shear bond strengths between alumina-blasted FRC and the luting agents were determined after 20,000 thermocycles. The FRC showed superior bond strength when compared with the RC-control. Highest bond strengths were achieved when FRC was bonded with Panavia F 2.0, Linkmax MC, Multibond, Super-Bond C&B, and MT, whereas Chemiace II trailed in the list of resin-based luting agents evaluated. Insufficient bonding was obtained with Fuji I. Results of the present study revealed that when fabricating restorations, the clinician should select an appropriate combination of resin composite material and luting agent so as to ensure the longevity of restorations.     

Tensile bond strength of two ceramic and three resin composite inlay materials placed using a resin luting agent.

The tensile bond strength of inlay materials to dentin was evaluated. Five materials, two direct resin composite inlay products, one hybrid resin composite, a preformed ceramic block, and a conventional porcelain material were bonded to bovine dentin and bonded together using a dual-polymerizing resin luting agent. Specimens were tested with and without thermocycling. Some bar-to-bar bonding groups fractured through the bar. Significantly higher (P < .05) bar-to-bar bonds were recorded than the bar-dentin bonds, irrespective of the inlay materials. VitaDur N showed the lowest bar-to-bar failure values (7.6 MPa) compared to the four other inlay materials (14.4 MPa to 22.2 MPa), but had the highest dentin bond strength (4.5 MPa). Unexpectedly, thermal loading increased the bond strength to bovine dentin, although this was only statistically significant for VitaDur N. The dentin bond strength of Charisma (1.4 MPa) was inferior (P < .02) to all other materials (2.6 MPa to 4.5 MPa) when thermocycled before testing.     

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.     

Bond strength of composite resin to glass ceramic after saliva contamination

Objectives

Purpose of this study was to investigate the effect of cleaning methods of glass ceramic specimens contaminated with saliva on tensile bond strength (TBS) to composite resin. Additionally, effect of water storage on bond strength was evaluated.

Materials and methods

Glass ceramic discs (IPS Empress, Ivoclar-Vivadent, FL) distributed among five groups (n?=?28) were etched with hydrofluoric acid, silanized, contaminated with human saliva, and in group W rinsed with water, group WS additionally silanized, group E rinsed with water and cleaned with ethanol, and group ES additionally silanized. Group C served as a control without contamination. Plastic screws were bonded to the glass ceramic discs using Variolink II (Ivoclar-Vivadent). TBS was measured after 24 h and after 150 days of storage. Failure modes were examined. ANOVA was applied to explore group effect on TBS. Pair-wise comparisons were calculated.

Results

The mean TBS [in megapascals] were for W 46?±?14, WS 55?±?8, E 48?±?11, ES 52?±?10, and C 50?±?8 after 24 h, and W 39?±?11, WS 53?±?9, E 48?±?8, ES 48?±?11, and C 50?±?8 after 150 days. After 150 days specimens of group W showed significantly lower TBS compared to group C (p?=?0.05). Additional silanization in group WS led to a significant increase of TBS compared to specimens of group W (p?=?0.003). Adhesive fractures were observed only in specimens without second application of silane.

Conclusions

The cleaning of the contaminated glass ceramic surface by rinsing only did not result in a durable bond.

Clinical relevance

Pre-silanized glass ceramic restorations need to be rinsed and treated with a fresh layer of silane after saliva contamination.     

The effect of surface treatment on the shear bond strength of luting cement to a glass-infiltrated alumina ceramic

PURPOSE: The aim of this study was to evaluate the effect of three different surface treatments on the bond strength of four different luting cements--three bis-GMA-based resin cements and a compomer cement--to In-Ceram. MATERIALS AND METHODS: Eight In-Ceram samples were used for each experimental group. The samples were randomly assigned three treatment conditions: (1) etching for 90 seconds with 5% hydrofluoric acid gel, (2) sandblasting (110-micron Al2O3), and (3) tribochemical silica coating. All samples were silanated following the surface treatment. The luting cements were bonded to In-Ceram specimens using Teflon tubes. All samples were thermocycled for 5,000 cycles altering between 5 and 55 degrees C with 30-second dwell times. The shear bond strength values were measured in a universal testing machine with a cross-head speed of 1 mm/min. Analysis of variance was used to analyze data. RESULTS: The mean bond strengths varied between 1.2 and 24.7 MPa. CONCLUSION: Shear bond strength of compomer cement following tribochemical silica coating was significantly lower in comparison to resin cements. Luting of In-Ceram with various resins provided varying degrees of bond strengths that were significantly increased by the tribochemical silica-coating system.     

Bond strength of three luting agents to zirconia ceramic - influence of surface treatment and thermocycling

Objective

This in vitro study aimed to evaluate the influence of different surface treatments, 3 luting agents and thermocycling on microtensile bond strength (µTBS) to zirconia ceramic.

Material and Methods

A total of 18 blocks (5x5x4 mm) were fabricated from zirconia ceramic (ICE Zirkonia) and duplicated into composite blocks (Alphadent). Ceramic blocks were divided into 3 groups (n=6) according to the following surface treatments: airborne-particle abrasion (AA), silica-coating, (SC) (CoJet) and silica coating followed by silane application (SCSI) (ESPE Sil). Each group was divided into 3 subgroups (n=2) according to the 3 luting agents used. Resin-modified glass-ionomer cement (RMGIC, Ketac Cem Plus), self-adhesive resin cement (UN, RelyX Unicem) and adhesive resin cement (ML, MultiLink Automix) were used for bonding composite and zirconia blocks. Each bonding assembly was cut into microbars (10 mm long and 1±0.1 mm²). Seven specimens of each subgroup were stored in water bath at 37ºC for 1 week. The o ther 7 specimens were stored in water bath at 37ºC for 30 days then thermocycled (TC) for 7,500 cycles. µTBS values were recorded for each specimen using a universal testing machine. Statistical analyses were performed using a 3-way ANOVA model followed by serial 1-way ANOVAs. Comparison of means was performed with Tukey''s HSD test at (α=0.05).

Results

µTBS ranged from 16.8 to 31.8 MPa after 1 week and from 7.3 to 16.4 MPa after 30 days of storage in water and thermocycling. Artificial aging significantly decreased µTBS (p<0.05). Considering surface treatment, SCSI significantly increased µTBS (p<0.05) compared to SC and AA. Resin cements (UN and ML) demonstrated significantly higher µTBS (p<0.05) compared to RMGIC cement.

Conclusions

Silica coating followed by silane application together with adhesive resin cements significantly increased µTBS, while thermocycling significantly decreased µTBS.     

Bond strength of luting cements to zirconium oxide ceramics

PURPOSE: This study was conducted to determine the bond strength of some resin luting cements to zirconia ceramic. The hypothesis was that adhesive bonding capacity is influenced by different surface pretreatments designed for milled ceramic inlays. MATERIALS AND METHODS: Composite cylinders 5 mm x 5 mm were light cured on the ceramic surfaces for a shear test conducted in a test jig. Five surface treatments were studied: as received (from the milling machine), sandblasting with either 250- or 50-micron alumina sand, hydrofluoric acid treatment, and grinding with diamond burs. The tested luting cements were Panavia 21, Twinlook, and Superbond C&B. RESULTS: All debonding occurred at the interface between ceramic and composite cement. Superbond demonstrated the highest bond strength regardless of the surface treatments. Grinding the surface with diamond burs improved the bonding slightly for Twinlook and Panavia 21 and also showed the roughest texture. Washing with hydrofluoric acid had no significant influence on bond strength. CONCLUSION: Bond strengths for Twinlook and Pananvia 21 were quite low, and only Superbond showed a bond strength reasonably acceptable for clinical use; however, as no standard for bond strength has been established for inlay therapy, the other cements cannot be rejected as luting cements for inlays.     

Bond strength of dental luting cements to titanium castings

This study compared the tensile bond strength of dental luting cements to the titanium castings with gold alloy (Type IV), 12% Au-Ag-Pd alloy and Ni-Cr alloy in dental clinical practice. In this experimental condition, the zinc phosphate cement did not adhere to any dental casting alloy tested. The tensile bond strength of polycarboxylate cement to the titanium castings was 96 kg/cm2, about two times as high as that gold alloy (Type IV). The tensile bond strength of the glass ionomer cement to titanium castings was 32 kg/cm2, about two times as high as that of dental precious alloys. The tensile bond strength of the adhesive resin cement to titanium castings was 220 kg/cm2, about three times as high as that of dental precious alloys.