Effects Of Different Smear Removal Methods On The Microleakage Of Class V Cavity In Young And Old People

Objective:To compare the generation of microleakage in the cavity after filling the Class V Cavity composite resin of young people and the elderly with Er:YAG laser(100 mJ,20 Hz),0.5 M EDTA solution and 35%phosphoric acid treated smear layer.Provide a basis for clinical applications.Methods:A total of 60 human isolated third molars were collected,with complete crowns and no cracks.Among them,young people(16-30 years old)have 30 molars,and the elderly(65+)have 30 molars.According to different treatment methods,the molars of young and old people were randomly divided into three groups,which were recorded as laser etching group,EDTA treatment group and phosphoric acid etching group,with 10 groups in each group.All the isolated teeth were prepared the Class V Cavity on the buccal side with a length of 4 mm and a depth of 3 mm.The laser group was etched with Er:YAG laser(100 mJ,20 Hz)for 60 s to make the walls blank;EDTA group The cavity was treated with 0.5M EDTA solution for 60s and rinsed.The phosphate group was treated with 35%phosphoric acid for 15 s for 15 s and then rinsed for 30 s.All the test pieces were combined with Adper~TMM Single Bond2 adhesive and used once with large volume resin.Scratch to reduce errors that may result from stratified filling.After polishing,the apical foramen were closed with wax and the teeth were sealed with transparent nail polish.After hot and cold cycles,the dye was immersed and sliced.The leakage of the dye was observed by a stereo microscope and photographed.The scanning electron microscope was used to observe the gap between the cavity wall and the filling body.Micro-gap,data analysis was performed using SPSS20.0 software package,dye infiltration grade data was analyzed by Kruskal-Wallis H test and Manu-Whiney U test;gap width between cavity wall and resin was analyzed by one-way analysis of variance(ANOVA).According to?=0.05 level,P<0.05 was considered statistically significant.Results:1.The microleakage of gingival wall was significantly greater than that of occlusal wall in both young and old people(P<0.05).2.The microleakage in the occlusal wall and gingival wall of the elderly was significantly greater than that in the young,with statistical significance(P<0.05).3.The microleakage score of 35%phosphoric acid etching group was the lowest in both the young and the elderly groups,whether in the occlusal or gingival walls,which was significantly different from that of laser etching and EDTA treatment(P<0.05).Conclusion:1.After Class V Cavity filling,the elderly are more likely to have microleakage than the young,and the gingival wall is more likely to produce microleakage than the occlusal wall.The microleakage after.2.35%phosphoric acid treatment is the smallest.Er:YAG laser and EDTA treatment can not replace phosphoric acid.