Effect of etching time and resin bond on the flexural strength of IPS e.max Press glass ceramic

Effect of Storage Time on Bond Strength Performance of Multimode Adhesives to Indirect Resin Composite and Lithium Disilicate Glass Ceramic

Purpose: To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage.

Methods and Materials: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter × 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (α=0.05).

Results: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU > SBU = control); however, no significant difference among the adhesives was observed after one year (p>0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU > SBU) and one year (control > SBU = ABU; p<0.05).

Conclusions: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass–based ceramic.

Influence of silane and heated silane on the bond strength of lithium disilicate ceramics - An in vitro study

Objectives:

To evaluate the effect of silane application and silane heat treatment on lithium-disilicate ceramic when bonded to composite resin.

Methods:

Twelve blocks of lithium-disilicate (LD) ceramic were fabricated and bonding surfaces were etched using 9.5% hydrofluoric acid (90 seconds). Three experimental groups resulted from the various surface treatment combinations, which included, no silane application (NS) (controls), silane application (S) and silane heat treatment (HS) (100°C for 5 minutesutes). Ceramic and composite resin blocks were bonded using an adhesive resin and light cured restorative composite as a luting agent, under standard conditions. A total of 90 specimen sticks (8 x 1mm²) were subjected to micro-tensile bond strength testing. The means of micro-tensile bond strength (µ-tbs) of the study groups were analyzed using t-test and ANOVA. The tested specimens were analyzed for mode of failure using scanning electron microscopy (SEM).

Results:

The highest µ-tbs value (42.6 ±3.70 MPa) was achieved for LD ceramics with heat-dried silane. Both silane application and heat treatment of silane resulted in significant (p<0.05) improvements in micro-tensile bond strength of LD ceramics when bonded to resin composite.

Conclusions:

The application of silane and its heat treatment showed significant improvement in bond strength of lithium disilicate ceramic when bonded to composite.

The Effect of Hydrofluoric Acid Etching Duration on the Surface Micromorphology, Roughness, and Wettability of Dental Ceramics

The current laboratory study is evaluating the effect of hydrofluoric acid etching duration on the surface characteristics of five silica-based glass ceramics. Changes in the pore pattern, crystal structure, roughness, and wettability were compared and evaluated. Seventy-five rectangularly shaped specimens were cut from each material (IPS e-max™, Dentsply Celtra™, Vita Suprinity™, Vita mark II™, and Vita Suprinity FC™); the sectioned samples were finished, polished, and ultrasonically cleaned. Specimens were randomly assigned into study groups: control (no etching) and four experimental groups (20, 40, 80 and 160 s of etching). The etched surfaces’ microstructure including crystal structure, pore pattern, pore depth, and pore width was studied under a scanning electron microscope, and the surface roughness and wettability were analyzed using a non-contact surface profilometer and a contact angle measuring device, respectively. The results were statistically analyzed using one-way analysis of variance (ANOVA) and the post hoc Tukey’s test. The results showed a significant change in the pore number, pore pattern, crystal structure, surface roughness, and wettability with increased etching duration. Etching for a short time resulted in small pores, and etching for longer times resulted in wider, irregular grooves. A significant increase in the surface roughness and wettability was observed with an increase in the etching duration. The findings also suggested a strong association between the surface roughness and wettability.