Comparison Of Three Polishing Sets On Surface Finish Of Zirconia Full Zircon Crown

Objective: To compare the surface roughness,surface morphology and adhesion of surface bacteria after polishing zirconia full zirconium crowns in three polishing sets,which are commonly used in clinical,and evaluate the polishing effect of three commonly used polishing sets on zirconia full zirconium crowns.A set with a relatively good polishing effect is screened to guide the clinical.Methods:1.Prepared zirconia specimens with a diameter of 10 mm and a height of 5 mm,and used a SHOFU green sand stone to grind under mild pressure to simulate clinical adjustment.2.The specimens were randomly divided into 5 groups: A group: SHOFU group,B group: EVE group,C group: Kerr group,D group: glazing group,E group: control group.Groups A,B,and C were polished in three different polishing sets according to the instructions provided by the manufacturer.Group D was glazed and sintered in a porcelain oven,and the E group did not do any treatment.3.The surface roughness value(Ra)of the test piece was measured with a roughness profiler,and the surface morphology of the test piece was observed under a scanning electron microscope(SEM).4.Resuscitation culture of Porphyromonas gingivalis(Pg W83),inoculation of Porphyromonas gingivalis suspension in 24-well cell culture plates containing each group of specimens in an anaerobic environment for 24 h at 37 ° C,plates colony counting method was used to determine the amount of bacterial adhesion on the surface,and the adhesion of the bacteria on the surface of the test piece was observed under a scanning electron microscope(SEM).5.The surface roughness value(Ra)and bacterial adhesion of the five groups of specimens were statistically analyzed by SPSS 17.0 software.Results:1.Surface roughness(Ra)results: The Ra values of groups A,B,C,D,and E were(0.33 ± 0.01),(0.45 ± 0.01),(0.55 ± 0.03),(0.12 ± 0.03),(0.55±0.05)?m;the Ra values of A,B and C groups increased in turn,and the difference between the three groups was statistically significant(P<0.05);the Ra values of C and E groups were the largest,and the difference between the two groups was no statistically significant(P>0.05);the Ra value of the D group was the smallest,and the difference was statistically significant compared with the other four groups(P<0.05).2.Bacterial adhesion results: The bacterial adhesions of groups A,B and C increased in turn,and the difference between the three groups was statistically significant(P<0.05).The bacterial adhesion of group C and group E was the largest.There was no statistically significant difference(P>0.05).The bacterial adhesion of group D was the smallest,and the difference was statistically significant compared with the other four groups(P<0.05).3.Scanning electron microscopy(SEM)observation results: Shallow scratches on the surface of specimens in group A and group B;wide and deep scratches and pit defects on the surface of specimens in group C and group E;The surface of specimens in group D was the smoothest,the shape was regular,and the defects were the least.The surface of the specimens in the A,B,C and E specimens were mainly distributed around the scratches and defects.The number of groups A and B was small,and the number of groups C and E was the highest.The surface of the specimens in group D was scattered and the number of bacteria was the least..Conclusion: Different polishing sets have different polishing effects on zirconia full zirconium crowns.Among the three polishing sets of SHOFU,EVE and Kerr under the current experimental conditions,the SHOFU set has the best polishing effect.