In-Vitro assessment of Er: YAG and Er: Cr YSGG laser surface treatment effect on shear bond strength of lithium disilicate on dentine in comparison with hydrofluoric acid.

Description :

This project is comparing the effect of Er: YAG or Er: Cr YSGG laser on the surface conditioning of lithium di-silicate (Ivoclar Vivadent, Schaan, Liechtenstein) and its effect on shear bond strength (SBS) to dentine. With surface conditioning of the same glass ceramic, with hydrofluoric acid (HF). To a control sample with no surface conditioning. To add on, teeth will be cut horizontally and prepared with 37% phosphoric acid for 3 seconds by a cutting machine (EXAKT Vertriebs GmbH, Germany). Then they will be bonded with Kuraray Clearfil Liner Bond F (Kuraray Noritake Dental Inc, Tokyo). Then light cured for 20 seconds with Eighteeth curing pen (Eighteeth Changzhou City, Jiangsu Province, China). The first hypothesis is that Er: YAG or Er: Cr YSGG surface treatment of lithium di-silicate will increase shear bond strength when compared to 9% HF acid etching for 20 seconds. And the second one will be that Er: CR YSGG laser will yield a higher bond strength for surface treatment of lithium disilicate when bonded to dentine when compared to Er: YAG. Sections of the samples will be viewed under a scanning electron microscope. SBS will be measured using a universal testing machine.