Experimental Study On The Effects Of Different Adhesives And Different Surface Mechanical Treatments On The Bonding Properties Of Zirconia Ceramics

Obiective The experiment was to study the effects of two different universal bonding materials and four kinds of caramic surface mechanical treatments on bonding of zirconia ceramics to dentin in vitro to provide reference for the clinical treatment of restorations adhesive.Method Processing 104 zirnonia cuboid specimens(4 mm×4 mm×6 mm),among which 24 specimens are choosed randomly in Experiment 1.And the remaining 80 specimens are prepared for Experiment 2.Experiment 1:After sandblasting,24 specimens are randomly assigned into 3 groups(n=8)according to different resin adhesives,control group:Group F(Panavia F2.0),experimental groups:Group R(Single Bond Universal/RelyXTM Ultimate ClickerTM)and group N(Optibond Versa Adhesive/NexusTM 3rdGeneration).After all specimens are randomly paired with prefabricated dentin embedding pieces,they are bonded strictly according to the instructions of each adhesive material.After constant temperature water bath for 24 hours,the shear strength of fifty bonding specimens is tested by universal testing machine,and the fracture mode is analyzed under the microscope.The data are statistically analyzed by SPSS 25.0.Experiment 2:the remaining 80 specimens are randomly assigned into 5 groups(N=16),A-untreated,B-sandblasted,C-Er:YAG laser,D-Nd:YAG laser,E-femtosecond laser.One specimen is randomly selected from each group to explore the microstructure by scanning electron microscope,and fives are selected from each group to measure surface roughness.After the remaining specimens are randomly paired with prefabricated dentin embedding pieces,they are bonded with resin material(Optibond Versa).The subsequent procedures are as the same as Experiment 1,and the results are statistically analyzed by SPSS 25.0.Result Different bonding materials has an effect on the bonding strength of zirconia surface modification(P<0.05).The difference between Group F and Group N,Group F and Group R is statistically significant(P<0.05).Group R and Group N are similar without statistically significance(P>0.05),and Group F is the smallest.Scanning electron microscopy images show that the micromorphology of zirconia surface of Groups B,C,D and E change significantly.Both of roughness and shear bond strength after surface treatments have statistically significant(P<0.05),and the improvement of Groups B and E is greater than Groups C and D(P<0.05).The change trend of shear bond strength is similar to that of roughness.The shear bond strength increases with the increase of roughness.The shear bond strength of Group E is lager than Group B(P<0.05).The maximum bond strength can be obtained by femtosecond.Conclusion The short-term bond strength obtained by using new universal adhesives of Single Bond Universal and Optibond Versa Adhesive alone is greater than that obtained by using traditional resin cement of Panavia.Femtosecond laser and sandblasting treatment can improve the short-term bonding strength of ceramics better than Er:YAG laser and Nd:YAG laser.After femtosecond laser treatment,the surface of zirconia shows microgroove array,which is beneficial to the mechanical bonding with resin adhesive.Femtosecond laser treatment is a promising mechanical treatment method.