The effect of silica-coating by sol-gel process on resin-zirconia bonding

Abstract

The effect of silica-coating by sol-gel process on the bond strength of resin composite to zirconia was evaluated and compared against the sandblasting method. Four groups of zirconia samples were silica-coated by sol-gel process under varied reagent ratios of ethanol, water, ammonia and tetraethyl orthosilicate and for different deposition times. One control group of zirconia samples were treated with sandblasting. Within each of these five groups, one subgroup of samples was kept in dry storage while another subgroup was aged by thermocycling for 6,000 times. Besides shear bond testing, the surface topography and surface elemental composition of silica-coated zirconia samples were also examined using scanning electron microscopy and X-ray photoelectron spectroscopy.Comparison of silica coating methods revealed significant differences in bond strength among the Dry groups (p<0.001) and Thermocycled groups (p<0.001). Comparison of sol-gel deposition times also revealed significant differences in bond strength among the Dry groups (p<0.01) and Thermocycled groups (p<0.001). Highest bond strengths were obtained after 141-h deposition: Dry (7.97±3.72 MPa); Thermocycled (2.33±0.79 MPa). It was concluded that silica-coating of zirconia by sol-gel process resulted in weaker resin bonding than by sandblasting.

Effects of some chemical surface modifications on resin zirconia adhesion

“…These methods would obviously result in various bond strengths. The sol-gel approach was reported to be still impractical for dental practice due to its long treating time (Lung et al, 2013). Tribochemical air abrasion method could deposit silica content on zirconia surface in the form of zirconium silicate with the transduction of high impact energy and increase resin zirconia bond strength (Hallmann et al, 2012;Lung et al, 2014).…”

Double‐Layer Surface Modification of Polyamide Denture Base Material by Functionalized Sol‐Gel Based Silica for Adhesion Improvement

“…Tetra alkoxysilane sol‐gel polymerization (Si (OEt) 4 ) is a gentle and convenient method of synthesizing amorphous silica gel, which under hypercritical conditions turns into monolithic silica glass . The homogeneity and purity of this sol‐gel‐derived silica film are comparable or even superior to the coatings obtained by other methods . Unlike air abrasion, this approach can coat large or complex areas of the substrate .…”

“…[9][10][11][12][13] The homogeneity and purity of this sol-gel-derived silica film are comparable or even superior to the coatings obtained by other methods. 10,[13][14][15][16][17] Unlike air abrasion, this approach can coat large or complex areas of the substrate. 9,[12][13][14]16 Then the coupling agents react with the substrate and establish much more hydrolytically stable chemical bonds compared to the mechanical retention obtained by blasting.…”

Sol&ndash;gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain

“…Modification of zirconia surface using silica glasses was introduced for improving the zirconia-to-resin bonding strength. 14,15 Moreover, this method would make it possible to improve the bonding between zirconia and veneering porcelain, since the feldspathic porcelain may fuse to the silica layer during firing. However, conventional methods for silica coating have been criticized for their adverse effects on mechanical properties (ie, producing surface flaws and phase transformations), as well as their expense.…”

“…14,16 A sol-gel method provides the powderless processing of glasses and thin films directly from the solution. During this process, an oxide network forms through hydrolysis and condensation of metal alkoxide precursors.…”