Effects Of Er:YAG Lasers With Different Energy On Domestic And Imported Zirconia

Objectives: To measure the changes in physical and chemical properties and bonding properties of domestic Upcera zirconia and imported Cercon zirconia after different energy Er:YAG laser treatments,and to determine the optimal energy value of zirconia after Er:YAG laser treatment.Comprehensive evaluation of zirconia.Methods: 12 pieces of 25 mm x 8 mm x 1 mm domestic Upcera zirconia ceramics(A)and imported Cercon zirconia ceramics(B)were produced,and they were randomly divided into 2 groups,Upcera zirconium oxide and Cercon zirconia six for each,respectively,used in the experiment 1,experiment 2.The experimental specimen of every experiment can be divided into 6 groups,Upcera zirconium oxide and Cercon zirconia for each.Thirty domestic Upcera zirconia ceramics(A)and imported Cercon Zirconia ceramics(B)of 25mm×8mm×1mm were prepared for experiment 3.They were randomly divided into 6 groups with 5 Upcera zirconia and 5 Cercon zirconia in each group.One 25 mm × 8mm × 1mm IPS e.max Press ceramic(C)was produced and used in experiment one after being treated with hydrofluoric acid.In experiment four,30 pieces of domestic Upcera zirconia ceramics(A)and imported Cercon zirconia ceramics(B)with 3mm × 3mm × 1mm specifications were randomly divided into 6groups.Five Upcera zirconia ceramics and Cercon zirconia ceramics for each group.Five 3mm × 3mm × 1mm IPS e.max Press ceramics(C)were produced,and treated with hydrofluoric acid and silane coupling agent method to adhere to isolated teeth.According to the treatment method,the above four experimental zirconia ceramics groups are divided into 6 groups: blank group(A0,B0)without any treatment,Er:YAG laser treatment group(100MJ-A1,B1;150MJ-A2,B2;200MJ-A3,B3;250MJ-A4,B4),sandblasting group(A5,B5).In experiment one,the surface morphology of A0 group,B0 group,A1-A5 group,B1-B5 group,and C group was observed by scanning electron microscope to evaluate the surface roughness after treatment.In experiment two,an X-ray diffractometer was used to determine the crystal phase structure of the A0 group,the B0 group,the A1-A5 group,and the B1-B5 group,and the stability after treatment was evaluated.In experiment three,an Instron 3345 micro-force testing machine was used to measure the three-point bending strength of the A0 group,the B0 group,the A1-A5 group,and the B1-B5 group to evaluate the mechanical properties after treatment.In experiment four,the Instron 3345 micro-force tester was used to measure the shear bonding strength of zirconia ceramics and IPS e.max Press ceramics test specimens bonded with Panavia F adhesive.The fracture mode of the test specimens was observed under a stereo microscope to evaluate the adhesion.One-way ANOVA analysis and LSD multiple comparison test were performed on the experimental data with spss 26.0 software.The test standard was ? = 0.05.Results: 1.The size of grain gaps on the surface of Er:YAG laser-treated zirconia varies,and there is still a big gap with the IPS e.max Press ceramic group treated with hydrofluoric acid.100 MJ Er:YAG laser energy can not significantly increase the surface roughness of zirconia,250 MJ energy is too large to generate micro-cracks,the surface roughness of zirconia after 150 MJ and 200 MJ treatment are significantly increased and there is no significant difference in the scanning electron microscope results.There is still a certain gap in the strength of domestic Upcera zirconia and imported Cercon zirconia.2.After the four energy parameters Er:YAG laser of 100 MJ,150MJ,200 MJ,and250MJ and sandblasted zirconia were used in this experiment,none of the tetragonal phase to monoclinic phase transition occurred,and the crystal phases were relatively stable..3.The three-point bending strength measured by the Instron 3345 micro-force testing machine showed that P>0.05 between the A1,A2,and A5 groups in the Upcera group was not statistically significant;the remaining pairwise comparisons were all P <0.05,and the differences were Statistical significance.In the Cercon group,P>0.05 in the B1 and B2 groups was not statistically significant;P>0.05 in the B3 and B4 groups was not statistically significant;the other two pairs were compared P<0.05,and the differences were statistically significant.There was a statistically significant difference between Upcera and Cercon group at P<0.05.In summary,100 MJ,150MJ Er:YAG laser treatment of zirconia materials has little effect on its mechanical properties.4.The shear bond strength measured by the Instron 3345 micro-force tester showed that P>0.05 in the A1,A2,A3,and A4 groups of Upcera zirconia group,which was not statistically significant.The other groups were compared in pairs.All P <0.05,statistically significant.In Cercon zirconia group,P> 0.05 in A1 group,A2 group,A3 group and A4 group was not statistically significant,and the pairwise comparison between the other groups was P<0.05,which was statistically significant.There was no statistical significance in the comparison between Upcera and Cercon group P>0.05.The bonding strength of the IPS e.max Press ceramic group was significantly higher than that of the Upcera zirconia and Cercon zirconia groups.Er:YAG laser group and sand blasting group are mainly dominated by zirconia-adhesive interface fracture mode,while the IPS e.max Press ceramic group is dominated by mixed fracture mode.Conclusion:1.150 MJ energy is the best energy value for Er:YAG laser treatment of zirconia.This energy has the smallest effect on the strength of the zirconia while increasing the surface roughness of the zirconia,and also achieved a large shear bonding strength.2.The bonding strength obtained by the Er:YAG laser treatment of zirconia is still smaller than that of sandblasting,and the gap is more obvious than that of the treated IPS e.max Press ceramics.But compared with the blank group,it effectively increased the shear bonding strength.3.Compared with imported Cercon zirconia,domestic Upcera zirconia still has a gap in strength and other aspects.