Heat Treatment of Pre-hydrolyzed Silane Increases Adhesion of Phosphate Monomer-based Resin Cement to Glass Ceramic

Abstract

This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Silane + Heat Treatment (oven) + Panavia F; G4: HF 9.6% for 20 s + Silane + Heat Treatment (hot air) + Panavia F; G5: Silane + Heat Treatment (hot air) + Panavia F; G6: Silane + Panavia F. Microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using stereomicroscope and scanning electron microscope (SEM) to categorize the failure types. Data were analyzed statistically using two-way test ANOVA and Tukey's test (=0.05). Heat treatment of the silane containing MDP, with prior etching with HF (G2: 13.15 ± 0.89a; G4: 12.58 ± 1.03a) presented significantly higher bond strength values than the control group (G1: 9.16 ± 0.64b). The groups without prior etching (G3: 10.47 ± 0.70b; G5: 9.47 ± 0.32b) showed statistically similar bond strength values between them and the control group (G1). The silane application without prior etching and heat treatment resulted in the lowest mean bond strength (G6: 8.05 ± 0.37c). SEM analysis showed predominantly adhesive failures and EDS analysis showed common elements of spectra (Si, Na, Al, K, O, C) characterizing the microstructure of the glass-ceramic studied. Heat treatment of the pre-hydrolyzed silane containing MDP in an oven at 100 °C for 2 min or with hot air application at 50 ± 5 ºC for 1 min, was effective in increasing the bond strength values between the ceramic and resin cement containing MDP.

Bond strength to ZLS ceramics at different etching times and cementation protocols after aging

“…The hydroxyl group (-OH) of MDP monomer can chemically react with the hydroxyl group of zirconia oxides [10]. That promotes a stable chemical bond resistant to hydrolytic degradation [18], which, however, may be weakened after thermal cycling [10] but still effective to promote zirconia bonding [19,20]. In the 30 s no-cycled groups (30SRc/ no-C, 30SUaRc/no-C and 30UaRc/no-C), the use of universal adhesive promoted higher bond strength values than silane.…”

Effects of ceramic primers and post-silanization heat treatment on bond strength of resin cement to lithium disilicate-based ceramic

“…De Carvalho et al [21] heated a pre-hydrolyzed silane containing MDP (Clearfil Ceramic Primer) in an oven at 100 °C for 2 min or applied hot air at 50 °C for 1 min. The results of that study indicated that both treatments were effective in increasing the bond strength values between the feldspathic ceramic and resin cement.…”

“…The lowest bond strength was found for a pre-hydrolyzed silane containing phosphate monomer-based MDP. Its manufacturer does not recommend hydrofluoric acid etching, because MDP monomer should be able bond to ceramic without acid etching treatment by very strong bonds to SiO 2 based ceramics and metal oxides [21]. Without the microporosities promoted by acid etching, the silane containing phosphate monomer-based MDP yielded approximately 19% (for heat treatment) and 29% (no heating) lower bond strength than those silanes applied to acid etched ceramic.…”

Can the silane heat treatment influence the bond durability between resin cements and a dental ceramic?

“…This is a monomer containing reactive organic group and monovalent hydrolysable group that form siloxane bonds between the inorganic phase of the ceramic and the organic phase of the applied resin cement [2][3][4][5]. The chemical bond promoted by the silane coupling agent is the main mechanism behind feldspathic ceramic adhesion to resin cements [6][7]. Furthermore, silane increases the surface energy of ceramic substrates and improves cement wetting, optimizing the microscopic interaction between cement and ceramic [6][7].…”

“…The chemical bond promoted by the silane coupling agent is the main mechanism behind feldspathic ceramic adhesion to resin cements [6][7]. Furthermore, silane increases the surface energy of ceramic substrates and improves cement wetting, optimizing the microscopic interaction between cement and ceramic [6][7].…”