| Objective:The aim of this experiment was to study the effect of resin adhesives with different materials and thicknesses on shear strength and fracture load of IPS e.max glass-ceramics after bonding.The differences of shear strength and fracture load of IPS e.max CAD and IPS e.max Press all-ceramic materials after bonding were compared under the same bonding thickness and material,in order to provide experimental guidance and theoretical fundament for material selection and optimal design of clinical prosthetic therapy.Methods:In this study,five commonly used resin cement(RelyX? U200,RelyX? Ultimate Clicker,Multilink N,Variolink N and Kerr NX3)were selected.The enamel of 144 fresh molars in vitro was removed.IPS e.max CAD ceramic blocks were processed into 132 sheet specimens.The experiment was carried out in three parts.1)The specimens were randomly divided into five groups,12 bonding specimens for each group of bonding materials,and the shear strength test and fracture load test were carried out respectively.By comparing the effects of five kinds of resin cement on shear strength and fracture load of IPS e.max CAD glass-ceramics after bonding,the optimum adhesive was selected.2)On the basis of experiment 1),the specimens were randomly divided into five groups,each group with 12 adhesive resin thicknesses of 40μm,80μm,120μm,160μm and 200μm,respectively.By measuring the shear strength and fracture load of five different thickness bonded specimens with the selected optimum bonding agent,and analyzing the fracture interface,the optimum thickness of the bonding agent was selected.3)The IPS e.max press ceramic blocks were processed into 12 pieces with the same specifications as IPS e.max CAD group.The best bonding agent and the best bonding thickness selected from the above experiments were used to complete the bonding of specimens.The shear strength and fracture load of the ceramic sheets were measured,and the fracture interface was analyzed.The difference of the shear strength and the fracture loading value between IPS e.max CAD and IPS e.max Press was compared under the same thickness and material of the adhesive resin.Results:1.U200 had the smallest fracture load value and shear strength,which was significantly lower than the other four groups.There was no significant difference in fracture load between RelyX? Ultimate Clicker,Multilink N,Variolink N and NX3.The shear strength of Mutilink N was significantly higher than that of NX3,but there was no significant difference between Mutilink N and Variolink N and RelyX? Ultimate Clicker.2.The fracture load value and shear strength of 160μm bonding group were the largest,and the fracture load was significantly higher than that of the other four groups,and the shear strength was significantly higher than that of 40μm and 80μm group.There was no significant difference between it and 120μm or 200μm group.3.The average fracture load value and shear strength of IPS e.max Press bonding group were higher than those of IPS e.max CAD group,but there was no significant difference between them.Conclusions:1.Five kinds of bonding specimens of different resin cement with IPS e.max CAD glass-ceramics had been tested with shear strength and fracture load.It was found that U200 had the lowest fracture load value and shear strength,and the bonding effect needs to be considered.2.Five groups of different thickness bonding specimens with IPS e.max CAD glass-ceramics were fabricated by using Multilink N resin bonding agent.Through fracture load and shear strength tests,160μm was selected as the optimum bonding thickness.3.The fracture load and shear strength of IPS e.max Press and IPS e.max CAD were similar under the same resin bonding agent Multilink N and the same bonding thickness of 160μm,while the latter was slightly weaker but no significant difference. |
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