The effect of silane applied to glass ceramics on surface structure and bonding strength at different temperatures

Shear bond strength between standard or modified zirconia surfaces and two resin cements incorporating or not 10-MDP in their matrix

OBJECTIVE

This study aimed first to compare the shear bond strength between zirconia samples luted to enamel with a 10-MDP- containing resin cement (Panavia F2.0, Kuraray, Japan) and those luted with a resin cement using a separated 10-MDP monomer-containing bottle (Panavia V5, Kuraray, Japan). The second objective was to evaluate the bond stability after 150 days of aging in water, between enamel and zirconia ceramic surface enhanced with a glass-ceramic coating.

MATERIALS AND METHODS

80 specimens composed of ceramic cylinders and enamel disks were obtained, within eight experimental groups (n = 10). 60 zirconia cylinders (Katana STML zirconia, Kuraray, Japan) were assigned to 3 groups according to their surface treatment: milled/sintered surface (ZRCT), tribochemical silica-coating (Cojet™ Sand, 3 M ESPE, Seefeld, Germany) (ZRTC), and glass-ceramic coating (IPS e.max Zirpress) (ZRZP). 20 cylinders of lithium disilicate had a milled surface (IPS e.max CAD, Ivoclar-Vivadent, Schaan, Liechtenstein) (ECAD). The cylinders of each group were further divided into two subgroups according to the resin cement used: Panavia F2.0 (-PF) and Panavia V5 (-PV). All specimens were stored in distilled water for 150 days before shear bond strength (SBS) tests. The fracture mode was analyzed, and data were statistically computed (two-way ANOVA, post hoc Tukey test, p < 0.05, SPSS, IBM, v26).

RESULTS

The ECAD-PF group recorded the highest SBS values (31.75 ± 2.2), and the ZRCT-PF group recorded the lowest values (5.59 ± 1.1). The two-way ANOVA test showed that ceramic surface treatment had a statistically significant effect on SBS (F (3,72) = 38.95, p < 0.001) while the type of ARC did not (F (1,72) = 2.40, p = 0.126). Tukey's post hoc test revealed no statistical difference between the ZRZP and the ZRTC or ECAD groups.

CONCLUSION

Within the limitations of this study, the PV resin achieved similar shear bond strength results between tribocoated zirconia and enamel compared to the one for glass-ceramic and enamel. Furthermore, a long-term durable bond, similar to the glass-ceramic one, was achieved with the heat pressed ceramic coated specimens. Thus, this new surface treatment could be recommended for anterior cantilever bridges for its fracture resistance and bonding ability.

Comparison of Silane Heat Treatment by Laser and Various Surface Treatments on Microtensile Bond Strength of Composite Resin/Lithium Disilicate

In the current study, we evaluated the effects of heat treatment (by Er:YAG or furnace) and various surface treatments on the microtensile bond strength (μTBS) of silanized lithium disilicate ceramic. Seventy lithium disilicate (IPS e. max Press; Ivoclar Vivadent) and composite resin (Tetric N-Ceram; Ivoclar Vivadent) blocks were made and distributed into seven groups (n = 10) at random: S: silanization alone; ALS: airborne particle abrasion (APA) and silanization; SC: APA modified with silica and silanization; SHT1: silanization and heat treatment by Er:YAG; SHT2: silanization and heat treatment performed in the furnace (100 °C, 1 min); HF: etching with HF; and HFS: etching with HF and silanization. Every ceramic specimen was cemented to a composite resin block after surface treatment. Cemented specimens were embedded into acrylic resin and were tested with the μTBS test. Data were analyzed using one-way ANOVA and Tamhane T2 tests (α = 0.05). The SHT1 group had the highest bond of strength compared to the other groups (27.46 MPa). The ALS group had the lowest strength of the groups (15.56 MPa). Between SHT2 and HFS (p = 1), the comparison of the mean µTBS values showed no significant differences. It was concluded that silane heat treatment increased the resin composite–ceramic bond strength; however, within the terms of μTBS, the Er:YAG laser treatment was more successful than other surface treatment applications.

The effect of different ceramic surface treatments on the repair bond strength of resin composite to lithium disilicate ceramic

This study aimed to evaluate the bonding abilities and long-term durability of different repair agents when applied to lithium disilicate ceramics (LDS). Blocks of IPS e.max CAD were prepared and divided into four groups according to the surface treatment: Monobond Etch & Prime (ME), K-etchant GEL+Clearfil Universal Bond (UB), Bondmer Lightless (BL), and K-etchant GEL+G-Multi Primer (GMP). All treated ceramic specimens were bonded to resin composite and light-cured. The micro-shear bond strength was measured after 24 h of water storage or 5,000 thermocycles. ME and BL showed significantly higher initial bond strengths than UB and GMP (p<0.05). After 5,000 thermocycles, there was no significant difference in ME (p>0.05), but BL and GMP showed considerable reduction in bond strength (p<0.05); moreover, the samples of UB were all de-bonded before testing. ME and BL proved to be effective surface treatment materials for LDS.

Bond strengths of three-step etch-and-rinse adhesives to silane contaminated dentin

This study aimed to evaluate the effect of silane coupling agent contamination on the microtensile bond strength (µTBS) of 3-step etch-and-rinse adhesives on dentin. Flat occlusal dentin surfaces were prepared and randomly divided into 8 groups (n=20) based on the tested adhesives; Scotchbond Multi-purpose or Optibond FL, with contamination of an experimental silane (2 vol% of 3-m ethacryloxypropyltrimethoxysilane at pH 4.5) before acid-etching, after-etching or after-priming; while the groups without silane contamination served as controls. µTBS data were analyzed by two-way ANOVA and Tukey's HSD tests at a significance level of 0.05. Additional specimens of contaminated dentin were used to analyze changes in the organic molecules by Fourier transform infrared spectroscopy (FTIR). Silane contamination before acid-etching did not significantly change µTBS (p>0.05), but contamination after-etching and after-priming significantly decreased µTBS of both adhesives (p<0.05). Silane contamination had an adverse effect on the dentin bond strength of 3-step etch-and-rinse adhesives especially after-priming.

The impact of restorative material and ceramic thickness on CAD\CAM endocrowns

Background

Endocrown restorations as a conservative approach to restore endodontically treated teeth still need in vitro investigation under fatigue and made in different materials. This study evaluated the effect of restorative material and restoration thickness on the maximum fracture load of endocrowns subjected to cyclic loading.

Material and Methods

Sixty (60) third molar teeth received an endocrown preparation with three different heights of remaining dental tissue (1.5, 3.0 or 4.5 mm). A leucite-based ceramic (LEU) and a lithium disilicate (LD) based ceramic were selected to manufacture the CAD/CAM endocrown restorations, totaling 6 groups (n=10). The specimens were subjected to fatigue loading (200N, 2 x 106 cycles, water) and then to the single load to failure test (1 mm/min crosshead speed). Data were analyzed by using two-way ANOVA and Tukey tests (p< 0.05).

Results

All endocrowns survived the fatigue test. The thickness did not influence the restoration’s fracture load (p=0.548) instead the restorative material (p=0.003). LD showed higher mean values (1714.43 N)A than LEU (1313.47 N)B.

Conclusions

Endocrowns manufactured with CAD/CAM lithium disilicate blocks showed superior fracture load than the leucite-based blocks after mechanical fatigue. Nevertheless, both materials presented acceptable survival and fracture load as long as the material’s minimum thickness and the enamel adhesion are respected.

Key words:Endocrown, CAD/CAM, Endodontically treated teeth, Failure load, Minimal intervention dentistry.

Physicochemical and morphological characterization of a glass ceramic treated with different ceramic primers and post-silanization protocols

OBJECTIVE

Evaluate the effect of different ceramic primers and post-silanization protocols on physicochemical and morphological characteristics of a lithium disilicate glass ceramic.

METHODS

Lithium disilicate ceramic (IPS e-max CAD) plaques (6 × 10 × 2 mm) were divided into 3 groups according to the ceramic primer used: (1) Silane (RelyX Ceramic Primer-RL); (2) Silane + MDP (Clearfil Ceramic Primer Plus-CP); (3) Self-etching ceramic primer (Monobond Etch and Prime-MB). Specimens from each group were distributed into 5 sub-groups according to post-silanization protocols: (a) Treated as recommended by the manufacturer (MR), (b) MR + Additional drying with air at room temperature for 30 s (RTA), (c) MR + additional drying with hot air for 30 s (HT), (d) MR + Surface rinsing with water at room temperature for 10 s and drying with air at room temperature for 30 s (WT), and (e) Specimens were not silanized (NS). Surface free energy (SFE) was determined using static contact angles measurements with water and diiodomethane. SFE data were submitted to Friedman followed by Wilcoxon post-hoc test (α = 0.05). Morphology was analyzed using scanning electron microscopy. Elemental composition and chemical interactions were determined with X-ray photoelectron spectroscopy analysis.

RESULTS

RL presented the highest SFE (62.4 mN/m) followed by CP (59.7 mN/m). Post-silanization protocols resulted in similar SFE, but WT and HT induced the highest water contact angles when using CP and RL. CP modified ceramics' surface morphology compared to the etched and RL treated groups. The presence of water was identified on CP treated specimen. All analyzed primers formed siloxane bonds with ceramic surface.

SIGNIFICANCE

Ceramic primers resulted in different surface free energy and morphology, but siloxane bonds were identified for all tested solutions. HT and WT protocols should be used with RL and CP primers. MB was not influenced by the different silanization protocols.

Simplified Surface Treatments for Ceramic Cementation: Use of Universal Adhesive and Self-Etching Ceramic Primer

The aim of this study was to evaluate the shear bond strength of resin cement and lithium disilicate ceramic after various surface treatments of the ceramic. Sixty blocks of ceramic (IPS e.max Press, Ivoclar Vivadent) were obtained. After cleaning, they were placed in polyvinyl chloride tubes with acrylic resin. The blocks were divided into six groups (n=10) depending on surface treatment: H/S/A - 10% Hydrofluoric Acid + Silane + Adhesive, H/S -10% Hydrofluoric Acid + Silane, H/S/UA - 10% Hydrofluoric Acid + Silane + Universal Adhesive, H/UA- 10% Hydrofluoric Acid + Universal Adhesive, MBEP/A - Monobond Etch & Prime + Adhesive, and MBEP - Monobond Etch & Prime. The light-cured resin cement (Variolink Esthetic LC, Ivoclar Vivadent) was inserted in a mold placed over the treated area of the ceramics and photocured with an LED for 20 s to produce cylinders (3 mm x 3 mm). The samples were subjected to a shear bond strength test in a universal test machine (Instron 5965) by 0.5 mm/min. ANOVA and Tukey tests showed a statistically significant difference between groups (p<0.05). The results of the shear strength test were H/S/A (9.61±2.50)^A, H/S (10.22±3.28)^A, H/S/UA (7.39±2.02)^ABC, H/UA (4.28±1.32)^C, MBEP/A (9.01±1.97)^AB, and MBEP (6.18±2.75)^BC. The H/S group showed cohesive failures, and the H/UA group was the only one that presented adhesive failures. The conventional treatment with hydrofluoric acid and silane showed the best bond strength. The use of a new ceramic primer associated with adhesive bonding obtained similar results to conventional surface treatment, being a satisfactory alternative to replace the use of hydrofluoric acid.

Resistência da união ao microcisalhamento de cimento resinoso e resina fluida à cerâmica de dissilicato de lítio

Objetivos: O objetivo neste estudo foi avaliar a resistência da união ao microcisalhamento de uma resina composta microhíbrida de baixa viscosidade (fluida) e de um cimento resinoso fotopolimerizável aplicados a uma cerâmica de dissilicato de lítio. Métodos: Discos de uma cerâmica de dissilicato de lítio (IPS e.max CAD, Ivoclar Vivadent) foram divididos em 2 grupos (n = 10), de acordo com material utilizado para a cimentação: cimento resinoso (Allcem Veneer, FGM) ou resina composta microhíbrida fluida (Opallis Fluida, FGM). Previamente a aplicação do material para cimentação, todas as cerâmicas receberam tratamento superficial padronizado: condicionamento com ácido fluorídrico a 10% (Condac Porcelana, FGM) por 20 s, lavagem com água por 60 s, secagem com ar por 30s e aplicação de silano (Prosil, FGM). Os materiais foram inseridos em uma matriz elastomérica (0,5 mm x 1,2 mm) sobre o bloco cerâmico. Quatro cilindros por grupo foram construídos e fotoativados por um aparelho de diodo emissor de luz (LED, Valo, Ultradent) por 40 s a uma irradiância de 1200 mW/cm2. O teste de microcisalhamento foi feito utilizando uma máquina de ensaio universal (EMIC) a uma velocidade de 0,5 mm/min. Os dados (MPa) foram submetidos ao teste de normalidade (Kolmogorov-Smirnov) e one-way ANOVA, sendo as médias comparadas pelo teste de Tukey (α=0,05). Resultados: O cimento resinoso apresentou resistência da união ao microcisalhamento estatisticamente superior à resina composta fluida (ρ=0,020). Conclusão: Melhor desempenho na união à cerâmica de dissilicato de lítio foi obtido utilizando cimento resinoso.

Bonding to silicate ceramics: Conventional technique compared with a simplified technique

Background

Silicate ceramic bonding is carried out by acid-etching with hydrofluoric acid (HF) followed by an application of silane. By replacing HF with ammonium polyfluoride, contained in the same flask as the silane, the number of steps in this clinical procedure, can be reduced, while maintaining bond strength values, and reducing toxicity. A shear bond test was performed to compare the conventional and the simplified surface treatment techniques.

Material and Methods

Twenty ceramic samples were fabricated from IPS emax CAD® ceramic (Ivoclar Vivadent) and divided into two groups (G1 and G2) (n=10). The conventional technique was applied to G1 samples, and the simplified technique to G2 samples. A resin cement cylinder was bonded to each sample. Afterwards, samples underwent shear bond strength testing in a universal test machine.

Results

G1 obtained 26.53±6.33 MPa and G2 23.52±8.41 MPa, without statistically significant differences between the two groups.

Conclusions

Monobond Etch&Prime appears to obtain equivalent results in terms of bond strength while simplifying the technique. Further investigation is required to corroborate these preliminary findings.

Key words:Shear bond strength, surface treatment, bonding to ceramic, hydrofluoric acid, ammonium polyfluoride.