Improving bonding of zirconia through deposition of silica layer via collosol-gelatin process, the roles of NaHCO3 / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To evaluate the effects of NaHCO3 on gelation of silica sols and shear bond strength of silica coated zirconia via collosol-gelatin (Sol-Gel) process.</p><p><b>METHODS</b>The gelation time of silica sols after being mixed with 1%, 3%, 5%, 7%, 10% concentrations of NaHCO3 was recorded. The one got the shortest gelation time was used for the following tests. Zirconia blocks were prepared and divided into five experimental groups according to surface conditioning methods: group A, alumina sandblasting; group B, sandblasting + tribochemical silica coating + silane; group C, sandblasting + silica coating via Sol-Gel process + silane; group D, sandblasting + silica coating via Sol-Gel process (NaHCO3 was used) + silane; group E, sandblasting + zirconia primer. A composite resin column was bonded on the treated zirconia surface with Bis-GMA based composite resin cement. All specimens were subjected to shear bond strength (SBS) tests.</p><p><b>RESULTS</b>The shortest gelation time of silica sols were found when silica sols was mixed with 10% NaHCO3. Group A showed the lowest SBS values of (4.12 ± 0.52) MPa, which was significant different from SBS of group B [(10.24 ± 2.78) MPa], C [(7.36 ± 1.59) MPa], D [(9.79 ± 2.07) MPa], D [(8.39 ± 0.49) MPa], and no statistical difference was found between group C and D.</p><p><b>CONCLUSIONS</b>The silica coating via Sol-Gel process can significantly improve the bond strength of zirconia, and NaHCO3 would not exert influences to bonding.</p>