| Objective: In this experiment,a comparative study of different treatment methods on the surface of zirconia was conducted to further verify that the hot acid etching method can effectively increase the surface roughness of zirconia and improve the shear bonding strength.And comprehensively consider the mechanical properties of flexural strength,comprehensively evaluate the clinical stability of domestic Altron zirconia and imported Cercon zirconia,and provide a basis for the wide application of thermally acid-treated zirconia in clinic and expand clinical indications.Materials and methods: Production of experimental specimens: Domestic and imported zirconia specimens of two specifications are prepared separately,Type I specimens: 55 pieces of 25 mm × 8mm × 1mm,Type II specimens: 3mm × 3mm × 1mm each of 25 Pieces;5 pieces of die-cast ceramic specimens(3mm × 3mm × 1mm).After all domestic and imported zirconia test pieces are ground and polished by water sandpaper,they are divided into 5 groups(n = 5)according to the processing method and hot acid etching time,and processed in the following ways: A1-E1 are Altron zirconia blank control group,110μm alumina blasting group,10 min hot acid etching group,30 min hot acid etching group,60 min hot acid etching group;A2-E2 are imported Cercon zirconia blank control group,110μm alumina blasting group,10 min hot acid etching group,30 min hot acid etching group,60 min hot acid etching group.Die-cast ceramics were used as group F(n = 5): hydrofluoric acid treatment for 60 s.All the treated specimens were ultrasonically washed in absolute ethanol for 30 min.All processed Type I test specimens were tested for three-point bending strength with an Instron 3345 micro-force tester,and an X-ray diffractometer(XRD)was used to observe the transformation of the crystal phase structure on the zirconia surface,microscope(SEM)was used to observe the surface morphology of zirconia;A selfmade mold was used to partially embed the isolated tooth with self-setting resin to prepare a standard sample and the processed type II test specimen was bonded.The Instron 3345 micro-force tester was used to measure the initial shear of the zirconia and die-cast ceramic specimens at the moment of fracture Force F(N),and calculate the shear strength;observe the fracture interface of the test piece with an optical stereo microscope.All the above data were statistically analyzed using SPSS19.0 software.The statistical test standard was set to P <0.05 with statistical significance.Results: 1.SEM results: 1)It can be seen that the surface of domestic Altron and imported Cercon zirconia in the blank control group of group A is smooth,and the grain structure is arranged regularly and densely;the surface of domestic Altron and imported Cercon zirconia in group B of 110μm alumina blasting group forms a stripe Dent-like structure;C,D,E 10 min,30min,60 min thermal acid-etched groups of domestic Eltron and imported Cercon zirconia surface grains widened to form a three-dimensional three-dimensional porous structure.2)No significant difference in surface roughness between groups C,D,E observed at 5000 times.2.Three-point bending test results:1)Three-point bending strength values: 1101.0 ± 118.9MPa for group A1,1684.2 ± 123.2MPa for group A2,985.8 ± 74.5MPa for group B1,1492.8 ± 110.1MPa for group B2,859.0 ± 85.8MPa for group C1,1337.2 ± 57.7MPa for group C2,and 814.0± 52.1MPa for group D1,The D2 group was 1292.8 ± 118.7MPa,the E1 group was 793.8 ± 72.2MPa,and the E2 group was 1241.2 ± 144.2Mpa.2)The comparison between group A and the other groups was statistically significant(P <0.05),the comparison between group B and the other groups was statistically significant(P <0.05),and there was no statistical comparison between the C,D,and E groups.Significance(P> 0.05).3)After the same treatment,the flexural strength of domestic Altron and imported Cercon zirconia has statistical significance.(P <0.05).3.Analysis of Crystal Phase Results on Zirconia Surface: There were no characteristic peak images of monoclinic crystal phase in Group A,Group B,Group C,Group D,Group E of domestic Altron and imported Cercon zirconia.4.Shear bond strength test results: 1)Shear strength values of each group: 5.20 ± 1.53 MPa in group A1,5.47 ± 1.33 MPa in group A2,8.13 ± 1.60 MPa in group B1,8.22 ± 2.40 MPa in group B2,11.58 ± 1.81 MPa in group C1,and 10.89 ± 1.43 MPa in group C2,D1 group was 11.42 ± 1.49 MPa,D2 group was 11.09 ± 2.39 MPa,E1 group was 11.20 ± 2.94 MPa,and E2 group was 11.02 ± 2.39 MPa.2)The shear strength values of groups C,D,and E were not statistically significant(P> 0.05),the shear strengths of group A and B,C,D,and E were statistically significant(P <0.05),and the shear strengths of group B and C,D,and E were statistically significant(P <0.05).3)After the same treatment,the shear strength values of domestic Altron and imported Cercon zirconia have no statistical significance(P> 0.05).4)The shear strength value of group F die-casting ceramics: 27.33 ± 2.67 MPa,which is statistically different from the shear strength of zirconia in this experiment(P <0.05).Conclusion: 1.Sand blasting and hot acid etching have increased the surface roughness of domestic Alcon and imported Cercon zirconia,and the hot acid etching roughness has increased more significantly.However,the increase in the surface roughness of zirconia has nothing to do with the hot acid etching time.After the same sandblasting or hot acid etching treatment,there is no significant difference in the surface roughness of domestic Altron and imported Cercon zirconia.2.Sand blasting and hot acid etching have increased the shear bonding strength of domestic Altron and imported Cercon zirconia.The effect of hot acid etching is more significant,but it is still significantly smaller than that of die-cast ceramics.After the same blasting or hot acid etching treatments,there was no significant difference in shear bond strength between domestic Altron and imported Cercon zirconia,and the increase in shear bond strength on the surface of zirconia had nothing to do with hot acid etching time.3.Sand blasting and hot acid etching have decreased the flexural strength of domestic Altron and imported Cercon zirconia,and the hot acid etching group had a more significant decrease.After the same blasting or hot acid etching treatments,the flexural strength of imported Cercon zirconia is better than domestic Altron zirconia.4.There is no obvious tetragonal phase to monoclinic phase change in the grain structure of domestic Altron and imported Cercon zirconia after sandblasting and hot acid etching treatment..It is speculated that the physical and chemical properties of domestic Altron zirconia and imported Cercon zirconia treated by sandblasting and hot acid etching are relatively stable. |
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