Impact of Silane-containing Universal Adhesive on the Biaxial Flexural Strength of a Resin Cement/Glass-ceramic System.

The aim of this study was to determine whether using a silane-containing universal adhesive as a silane primer in glass-ceramic/resin cement systems affects biaxial flexural strength (BFS) and bonded interface integrity after loading. Glass-ceramic (IPS e.max CAD, Ivoclar/Vivadent, Schaan, Liechtenstein) disc-shaped specimens (6.5±0.1mm in diameter, 0.5±0.1mm thick) were etched with 5% hydrofluoric acid (HF) for 20 seconds and divided into four groups of 30 specimens, to be treated as follows: 1) One bottle silane primer (RCP); 2) Separate application of silane and adhesive (RCP+SB); 3) Silane-containing universal adhesive (SBU); 4) No treatment (C). After silanization, all specimens were resin cement- coated and polymerized for 40 seconds. Each specimen layer was measured, as well as each assembly's thickness, using a digital caliper and scanning electron microscope (SEM). Specimens were stored for 24 hours and submitted to a BFS test (1.27 mm/min). BFS values were calculated using the bilayer disc-specimen solution. Bonded interfaces were analyzed on fractured fragments using SEM. One-way ANOVA and Tukey tests (α=0.05) were applied, as well as the Weibull analysis. Factor "silane treatment" was statistically significant ( p<0.0001). RCP+SB (372.2±29.4 MPa) and RCP (364.2±29.5 MPa) produced significantly higher BFS than did the C (320.7±36.3 MPa) or SBU (338.0±27.1 MPa) groups. No differences were found in the Weibull modulus ( m: RCP: 10.1-17.3; RCP+SB: 10.1-17.0; SBU: 12.3-22.4; C: 7.4-12.9). Bonded interface analysis exhibited ceramic-cement separation (SBU, C) and voids within the resin cement layer (all groups). Neither the ceramic/cement system's BFS nor its bonded interface stability were improved by SBU after loading.

Short- and Long-Term Bond Strength Between Resin Cement and Glass-Ceramic Using a Silane-Containing Universal Adhesive.

This study aimed to evaluate the effect of various silane-containing solutions on bonding between resin cement and glass ceramic after 24 hours and after six months of water storage. Glass-ceramic plaques (IPS e.max CAD) were sandblasted with aluminum oxide, etched with 10% hydrofluoric acid (HF), and divided into five "silane treatment" groups: RelyX Ceramic Primer (RCP), RelyX Ceramic Primer and Single Bond Plus (RCP+SB), Scotchbond Universal (SBU), Clearfil Ceramic Primer (CP), and no solution (HF-only control). Each group was divided into two "storage time" subgroups: 24 hours or six months in 37°C water. Eighteen resin cement cylinders (RelyX Ultimate) were bonded to each treatment group substrate (n=18) and then subjected to microshear testing. Failure mode was analyzed using scanning electron microscopy. Debond data were analyzed using a two-way analysis of variance and the Tukey post hoc test (α=0.05) as well as Weibull distributions. The factors "silane treatment," "storage time," (p<0.0001), and their interaction were statistically significant (p<0.0010). Group means (MPa±SD), RCP (24 hours: 27.2±3.1; six months: 18.0±4.9), and HF-only control (24 hours: 21.1±3.4; six months: 15.7±5.8) showed a reduced bond strength after six months of water storage, while RCP + SB (24 hours: 23.4±4.4; six months: 22.2±5.4), SBU (24 hours: 18.8±3.0; six months: 17.2±3.6), and CP (24 hours: 21.7±4.3; six months: 17.4±4.8) remained constant. Weibull analysis revealed that more reliable bond strengths were obtained after six months for SBU and RCP + SB. Evaluation by scanning electron microscopy revealed that all groups demonstrated hydrolytic degradation at six months of storage, but RCP + SB and SBU indicated less. Use of a separate application of silane and adhesive system improved short and long-term ceramic/resin cement bond strength.