Effect Of Different Surface Treatments On The Bonding Strength Between Glass Ceramics And Resin

Object:The main objective of this study was to evaluate the effect of different surface treatments on the shear bond strength(SBS)between glass ceramic and resin.Nd:YAG laser as a ceramic surface etching method is easy to operate and harmless to soft tissues.However,the same laser treatment has different effects on the pretreatment of different ceramics,mainly because the morphology and structure of the ceramics are not the same.Therefore,laser pretreatment research of new ceramic zirconia-reinforced lithium silicate(ZLS)Celtra Duo ceramics is needed,and two commonly used ceramic types are compared,namely leucite-reinforced glass ceramic IPS Empress CAD and lithium silicate glass ceramic IPS e.max CAD.The effect of Nd:YAG laser surface treatment is controversial.This research is compared with the commonly used HF acid etching method and the method of HF and Nd:YAG laser combined application to explore the most suitable method for ceramic pretreatment.Methods:Under running water,using a hard tissue microtome,the ceramic block was cut into test pieces with a size of 5 mm × 5 mm × 4 mm,and the IPS e.max CAD test pieces were sintered in a porcelain furnace.Then place the test piece under running water according to the following surface treatment,after sanding with 600 mesh,800 mesh,and 1000 mesh sandpaper,and ultrasonically divide the three different CAD / CAM ceramics into 4 groups: blank control group,4.5% HF acid etching group;Nd:YAG laser irradiation group;Nd:YAG laser and HF acid etching group.The surface morphology of each sample after pretreatment was evaluated with a scanning electron microscope.Then,a silane coupling agent and a resin adhesive(Variolink N)were applied to each porcelain block to bond with the resin.Put all bonded test pieces in distilled water at 37 ° C for 24 h.After taking out,place the bonded test pieces on a universal testing machine,measure the SBS value of the bonded test pieces,and analyze the bonding failure mode after fracture.Data analysis was performed using SPSS 25.0 software.For SBS analysis,measurement data were analyzed using twoway ANOVA and LSD multiple comparison tests,p <0.05.Result:The surface of each group of ceramics etched by HF has a certain degree of crystal exposure due to the dissolution of the glass phase.Filled particles can be observed after Celtra Duo ceramic treatment,while the voids left on the surface of IPS Empress CAD are relatively small.Obviously,IPS e.max CAD can observe lithium silicate crystals with different directions.After the Nd:YAG laser treatment,the surface of the Celtra Duo ceramics became rough,the surface of the IPS Empress CAD was obviously damaged and pits appeared,and cracks and bubble-like damage occurred after the explosion of the IPS e.max CAD;The surface morphology of Nd:YAG laser after treatment is similar,and it also has the phenomenon of glass phase dissolution;In Celtra Duo,the SBS value was highest in NY group(14.80 MPa),followed by NY + HF group and HF group.The HF group(13.54 MPa)obtained the highest SBS value of IPS Empress CAD specimens(p <0.05),and no significant difference was observed in the other groups(p> 0.05).In the IPS e.max CAD,the HF group(14.70 MPa)showed the highest bond strength,followed by the NY + HF and NY groups.There was no significant difference between the NY and NY + HF groups(p> 0.05).Conclusion: 1.The type of surface treatment and the ceramic material have an influence on the bonding strength between the composite resin and glass ceramic.2.The Nd:YAG laser irradiation technology significantly improved the SBS value of Celtra Duo and IPS e.max materials.The laser parameters(150 mJ / pulse and 20 Hz for 20 s)of this experiment are applicable to Celtra Duo ceramics,and its effect Can replace HF acid etching.But this parameter is not suitable for IPS EmpressCAD.3.There is no significant difference between the treatment of NY + HF and the treatment using Nd:YAG laser alone.