Effect Of Er:YAG Laser Treatment On The Bonding Strength Of Leucite Glass Ceramic To Resin

Objective:This paper discusses the change of shear bonding strength and surface morphology of the bonding surface between leucite glass ceramic and resin after Er:YAG laser treatment,and expounds the effect and principle of Er:YAG laser treatment with different power on the bonding performance of the bonding surface of ceramic restoration,so as to provide reference for clinical operation.Methods:IPS Empress CAD glass ceramic blocks were prepared into 847mm×6mm×3mm ceramic samples,and randomly divided into 7 groups according to different surface treatment methods(12 samples for each group): control group,acid etching group,2W laser group,4W laser group,6W laser group,8W laser group and 10 W laser group.Surface treatment was carried out on the samples of each group: the control group was not treated,the acid etching group was treated with 9.5%hydrofluoric acid,and the 2W laser group,4W laser group,6W laser group,8W laser group and 10 W laser group were treated with Er:YAG laser with power of 2W,4W,6W,8W and 10 W respectively.After the surface treatment of the samples was completed,10 samples from each group were selected and tested by an electronic universal testing machine to detect the shear bonding strength(SBS)of the treated surface after bonding with the resin,and then the adhesion failure mode of the bonding section was observed by an optical stereoscopic microscope.Scanning electron microscope(SEM)was used to observe the surface morphology of the other two samples in each group.Results:1)SBS statistical analysis of each group showed: compared with the control group,the SBS value of other groups increased(P<0.01);the SBS values of the 2W laser group,4W laser group,6W laser group,8W laser group and 10 W laser group increased successively(P<0.01);when compared with the acid etching group,the SBS values of the 2W laser group,4W laser group,6W laser group and 8W laser group all decreased(P<0.01),while the difference of the SBS values between the 10 W laser group and the acid etching group was not statistically significant(P>0.05).2)The statistical results of adhesion failure modes show that the adhesion failure modes of each group are mainly adhesive failure modes,occasionally mixed failure,and no cohesive failure.3)The SEM results showed that the surface of the control group is smooth and unchanged;many irregular grooves with different depth can be seen in the acid etching group,presenting an obvious honeycomb structure;in the 2W laser group,the pits formed by the peeling of porcelain layer in a small range were observed,in the 4W laser group,the area and depth of pits were increased,in the 6W laser group,continuous bulk peeling was observed,in the 8W laser group and the 10 W laser group,the number of pits increased,presenting an obvious scale-like appearance.Conclusion:1)Er:YAG laser treatment can increase the bonding strength between the surface of the leucite glass ceramic and the resin to a certain extent.2)With the increase of Er:YAG laser processing power,the bonding strength between the surface of leucite glass ceramic and resin also increases.3)When the processing power of Er:YAG laser does not reach10 W,the shear bonding strength between leucite glass ceramic and resin cannot reach the level similar to that of the hydrofluoric acid treatment,but when the power reaches 10 W,reachable.