Er,Cr:YSGG Laser Treatment Of Zirconia Prosthesis To Enhance The Bond Strength Of Brackets

Objectives The Er,Cr: YSGG lasers with different values of power,frequency and water were used to conduct orthogonal test.The shear strength values of each group were compared to investigate the factors affecting the shear strength of zirconia restorations after bonding brackets.The primary and secondary relationships of the influencing factors,and the Er,Cr:YSGG laser processing parameters for improving the surface bracket bond strength of zirconia restorations were obtained by orthogonal test.Then,the Er,Cr:YSGG laser treatment of the optimal parameters obtained by orthogonal experiment was compared with the surface treatment methods of sand blasting and hydrofluoric acid etching to study the surface morphology of zirconia restorations treated by different surface methods.Shear strength,roughness and binder residue index provide experimental basis for clinically selecting the ideal surface treatment of zirconia prosthesis.Methods 1 Three factors of orthogonal test: A power,B frequency,C water volume.Each factor has three levels A1(power 4W),A2(power 5W),A3(power 6W);B1(frequency10Hz),B2(frequency 20Hz),B3(frequency 30Hz);C1(water 10%),C2(water volume 20%),C3(water volume 30%).Prepare zirconia test pieces that meet the test requirements and establish an orthogonal test table,The Er,Cr:YSGG laser was used to treat the surface of the test piece and bond the brackets with the parameters in the orthogonal analysis table.Then,the test piece is placed in a thermal cycler for temperature cycling,and after taking out,the shear strength is tested by a universal testing machine,orthogonal analysis was used to investigate the effects of three factors A,B and C on the shear strength of the bracket,and the optimal combination of parameters was selected.2 The optimal parameter setting of Er,Cr: YSGG laser treatment is compared with sand blasting and hydrofluoric acid etching.The prepared 32 zirconia specimens were randomly divided into 4 groups(n=8),the E group was the blank control group without treatment;the F group was Er,Cr:YSGG laser treatment;the G group was sandblasted;the H group hydrogen was used.Fluoric acid etching treatment.After the test pieces of each group are processed,the roughness value is measured by a roughness meter,one test piece was randomly selected from each experimental group,and the microscopic morphology of the surface of the test piece was observed by a scanning electron microscope,and then infrared spectrum analysis was performed,then,the bracket of the right upper central incisor was bonded with 3M Transbond adhesive,and the test piece after bonding the bracket was subjected to the hot and cold cycle test,and the shear strength test was performed,and the test piece after the bracket was removed was used with a digital microscope.The residual index of the zirconia surface binder was calculated.The shear resistance and roughness of each group were analyzed by ANOVA using SPSS17.0 software package,and the binder residue index was subjected to rank sum check,the morphology and the difference of the elements contained in the zirconia surface after scanning by four treatment methods were compared.Results 1 By orthogonal test,the optimal parameters of Er,Cr: YSGG laser are A: 6W,B: 10 Hz,C: 10% water.The effects of power,frequency and water volume on shear strength were significantly different(P<0.05),and the parameters that mainly affected the shear strength were power.The results of the four groups of shear strength were compared.The shear strength of group F was higher than that of group E and group H,the difference was statistically significant(P<0.05);the group of group F was higher than group G but the difference was not statistically significant(P>0.05);the bonding of group H The intensity was higher than that of E and G groups,and the difference was statistically significant(P<0.05).The roughness values of the four groups were compared by two to two.The results showed that the roughness of group G was higher than that of group E,group F and group H,the difference was statistically significant(P<0.05);the roughness of group F was higher than that of group F.The difference of E was statistically significant(P>0.05);the roughness of group H was higher than that of group E,and the difference was statistically significant(P<0.05).The binder residue index of the four sets of specimens after removal of the brackets was compared in the H group>F group>E group>G group,the difference was statistically significant(P<0.05).The surface structures of the prostheses treated with E,F,G and H were observed by scanning electron microscopy.The surface of group E was smooth with a small amount of impurities.The surface of group F had scattered shallow pit-like structures,but it was oxidized.Zirconium surface damage is limited,and some smooth surfaces are still preserved;the surface roughness of G group is obviously increased,it is granular depression and there are obvious traces of alumina falling out after embedding;the surface of group H is irregularly damaged and has a large number of undercuts.The cut portion is bladed.The surface elements of E,F,G and H were analyzed.The content of elements in group F was the same as that in group E.The carbon content in group G was significantly increased.The new group of fluorine was found in group H,and the content of other elements was not changed.Conclusions 1 Er,Cr:YSGG laser power,frequency and water content all affect the bonding strength of zirconia repair surface bonding bracket.The optimal parameter combination is 6W power 10 Hz frequency 10% water content.2.Compared with sandblasting and hydrofluoric acid etching treatment,Er,Cr:YSGG laser treatment of zirconia restoration surface has the advantages of low roughness,small damage to zirconia surface,high adhesion strength of supporting groove and high adhesive residue index after removing supporting groove.Figure20,Table10,Reference 134...