Comparison of the Shear Bond Strength of Acid Etched and Er,Cr:YSGG Laser Irradiated IPS Empress II and Feldspathic Ceramic Surfaces to Metal Brackets: an in-Vitro Study

Abstract

In this experimental study, the effects of Er,Cr:YSGG laser on the shear bond strength (SBS) of brackets bonded to two ceramic surfaces (Feldspathic and IPS Empress II) were compared to hydrofluoric (HF) acid etching. 60 ceramic discs were prepared, including two groups: Feldspathic and IPS Empress II surfaces. In each group, the following subgroups were prepared: 2W Er,Cr:YSGG laser, 2.5W Er,Cr:YSGG laser, and HF acid-etching. Ceramic primer and adhesive resin composite were applied and then light-cured to bond the ceramic cylinders to brackets. The samples were stored in distilled water for 24h and then, thermocycled. SBS testing was performed with a universal testing machine. Two-way ANOVA was used to compare SBS among subgroups (P<0.05). The highest SBS was seen in feldspathic surfaces with HF preparation (14.61±3.11MPa). There was a significant difference in SBS between different surface treatments except between the laser groups of IPS Empress II. Also, feldspathic surfaces had significantly higher SBS than IPS Empress II in all groups except HF. Conventional surface treatment provides much stronger adhesion than laser regardless of the ceramic type. Er,Cr:YSGG laser is effective on the SBS of the feldspathic ceramics, but not in IPS Empress II ceramics. So, laser treatment can be recommended as a favorable setting for treating feldspathic surfaces.