The effect of Etching of porcelain with Hydroflouric acid (HF) on Shear bond Strength using one coat bond and a self cure composite

The aim of this study was to compare the etching effect of porcelain with Hydroflouric acid (HF) one shear bond strength using one coat bond and self cure composite. Methods & Materials: The study was conducted experimentally using observation as its technique. 40 porcelain cubes were prepared and assigned into 4 groups. Group I specimens were treated with 35% phosphoric acid. Subsequently one coat bond was applied to bond the bracket, group II specimens were made fresh with fine diamond bur, treated with a 35% phosphoric acid and one coat bond was applied to bond the bracket, group III specimens were treated with a 20% hydroflouric acid (HF) and Nomix composite bond was applied to bond the bracket, group IV specimens were treated with a 40% HF acid and the same procedure in the group III was followed. The Instron machine was used at a crosshead speed of 0.5 mm/min to test the shear bond strength. The shear strength was 2.47±1.8 Mpa for group I, 5.64±2.6 Mpa for group II, 3.28±1.8 Mpa for group III and 3.03±2.6 for group IV. The overall difference between the four groups was statistically significant (P<0.05). The use of fine diamond bur and 35% phosphoric acid for Etching and use of one coat bond can achieve a successful bond between either use only phosphoric acid or 20% HF acid-Etched with Nomix composite and 40% HF acid etched with No mix composite.