Effect of etchant type and the use of silane on the shear bond strength of composite resin to porcelain

Abstract EN

Background : this study was formulated to compare the effect of 5 % hydrofluoric acid in comparison to 37 % phosphoric acid with and without the application of silane on bond strength of composite to porcelain.

Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameter and 4mm-thickness) and ceramic veneering.

Thirty two specimens were prepared, sandblasted with 50 μm aluminum oxide, and divided into four groups of eight samples.

Groups I and III were etched with 37 % phosphoric acid while groups II and IV were etched with 5 % hydrofluoric acid ; and groups I and II were silaneted while groups III and IV were not.

Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mmdiameter and 4mm-height).

Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles.

Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm / minute.

Results : mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV).

Paired-t revealed that specimens treated with 5 % hydrofluoric acid were significantly higher than those treated with 37 % phosphoric acid regardless the use of silane.

The use of silane dramatically enhanced the bond strength of composite resin to porcelain for both acids.

All specimens treated with 37 % phosphoric acid without silane showed adhesive failure, while those treated with 5 % hydrofluoric acid showed mostly cohesive failure within ceramic.

Conclusion : silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performed greater bond strength compared to phosphoric acid.