Comparative Study On The Translucency Of Dental Zirconia Materials And Tooth Dentin

Objective: The color of uncolored dental zirconia seems like the color of ivory because of its poor translucency.Thus,it can not fully meet the requirements of dentists and patients on the aesthetic performance of restorations in clinical practice.If the translucency of the basal crown made of dental zirconia can match the natural dentin tissue,then there will be less veneered porcelain to be used during the restoration process.Not only can we retain more dental tissue,but also allow the restoration to achieve the desired aesthetic effect.Measure the transmittance of natural dentin of different age groups and dental zirconia,and explore the difference between the translucency of natural dentin of different age groups and different dental zirconia.Through the comparative study on the translucency of dental zirconia and natural dentin,we can improve the production process of dental zirconia and then choose the proper dental zirconia in clinical.This can meet the patient's requirements for the aesthetic performance of the restoration.Methods: A total of 45 teeth from different age groups were collected.Then all the teeth were divided into three groups according to age,15 samples per group.The age of the young group,middle-aged group and elderly group is 15-44,45-60 and61-90,respectively.The sample was prepared as a section of dentin tissue with a thickness of 1 mm and a minimum diameter of not less than 5 mm for the first experiment.Three kinds of dental zirconia brands(Upcera ST porcelain block,Edit HT high permeability ceramic block,Zirconia Block HT ceramic block)were selected,which is commonly used and appearing better translucency.Then we selected 5 samples of each brand and then prepared samples with a size of 10 * 10 * 1mm for the second experiment.The spectrophotometer was used to measure the percentage of transmittance tooth dentin sample and the dental zirconia sample in the visible light range.Each sample wasmeasured three times and averaged.The SPSS21.0 software was used to perform one-way analysis of variance and LSD multiple comparison test on the measurement results of tooth dentin samples and zirconia samples,P<0.05.We selected one sample from each group and then observed them by using the scanning electron microscope.Results:1.The results of direct measurement of dentin shows that the translucency of dentin in different age groups is statistically different(P <0.05).The dentin translucency in the young group is higher than that in the middle-aged group,and the lowest in the elderly group.Scanning electron microscope results show that the number of open dentin tubules in the young group is more than that in the other two groups,followed by the middle-aged group,the oldest is the least.The amount of intratubular deposits in the young group was less,and the deposits in the dentin tubules of the elderly group increased significantly.As the age increases,the diameter of the dentin tubule gradually becomes smaller,and individual dentin tubules are closed.2.The LSD multiple comparison test results of the three groups of dental zirconia show that there is no significant difference in the average transmittance measurement results of the three groups of dental zirconia in the visible light range of 380-780nm(P> 0.05),which indicates that there is no significant difference in the translucency of the three groups.Scanning electron microscopy results show that the three groups of dental zirconia grains have the same grain diameter,but compared with the other two dental zirconia materials,the grain size of Zirkonzahn HT ceramic block is more uniform.3.In the visible light wavelength range of 380-780 nm,the comparison between the average transmittance of tooth dentin and dental zirconia shows that the average transmittance of the young group is higher than that of the three groups of dental zirconia,the difference is statistically significant(P <0.05).There is no statistically significant difference between the average transmittance of the middle-aged group and the three zirconia(P> 0.05).The average transmittance of the elderly group is lower than the three zirconia ceramic materials,the difference is statistical academic significance(P <0.01).Conclusion:1.The translucency of tooth dentin gradually decreases with age.This change may be caused by the aging change of the microstructure of the dental hard tissue.In clinical repair treatment,the influence of age on translucency should be considered,and appropriate repair materials should be selected.2.There is no significant difference in the translucency of the three brands.Scanning electron microscopy results show that the grains of the imported brand Zirkonzahn HT ceramic blocks are relatively more uniform,which may be the direction for domestic zirconia brands to further improve.3.When clinically repairing dental defects or dentition defects in middle-aged and elderly people,Altron ST porcelain blocks,Editor HT high-permeability ceramic blocks,and Zirkonzahn HT ceramic blocks can be used as a good choice to achieve a better aesthetic restoration effect.Young patients should choose dental zirconia with higher translucency when repairing dental defects or dentition defects.