Effect Of Er:YAG Laser Etching With Different Energy Densities On Microleakage Of Pit And Fissure Sealant

Objective:In this experiment,Erbium doped yttrium aluminum garnet laser(Erbium:yttrium aluminum garnet,Er:YAG)with different energy densities was used to etch the surface of pit and fissure,and the pit and fissure sealant was performed.The effects of Er:YAG laser etching of tooth pit and fissure surface with different energy densities on the micro leakage of pit and fissure sealant were compared,so as to provide some experimental basis for the clinical application of Er:YAG laser etching in pit and fissure sealant.Methods:A total of 72 caries-free third molars at the age of 18 and 30 years old were selected to remove dental calculus and periodontal soft tissue on the surface of teeth.The experimental samples were randomly divided into 9 groups(n=8):acid etching group(E1)and the laser groups(L1,L2,L3,L4),laser/acid etching groups(LE1,LE2,LE3,LE4),R14 handle,adjust the laser in non-contact mode,set laser parameters:MSP mode,spot diameter 1.3mm,ratio soda:(8:4)mL/min,irradiation speed of 1 mm/s,the frequency of 20 Hz,laser energy:L1,LE1:100m J;L2,LE2:120m J;L3,LE3:140m J;L4,LE4:160m J.LE1,LE2,LE3,LE4 were treated with 37% phosphoric acid after laser treatment,and 8 cases in each group were treated with sealant for pit and fissure sealant.All samples were cut after soaking in 1% methylene blue for 24 hours.The leakage degree between the sealant and the pit and fissure interface was observed by the stereo microscope,the score results were recorded,the operating time of three different tooth surface treatment methods were recorded,and all data were statistically analyzed.Results:1.The degree of microleakage was observed under stereo microscope(x40).Different degrees of dye leakage were observed in each group.The microleakage score of9 groups was tested by Kruskal Wallis H test rank sum test,P<0.01,indicating that there was significant difference in microleakage among acid etching group,laser group and laser/acid corrosion joint group.The difference of microleakage between laser group and laser/acid corrosion joint group was statistically significant(P<0.05),indicating that the microleakage value of laser/acid corrosion joint group was lower than that of single laser group.There was no significant difference in microleakage between two groups in the laser group(P>0.05),and there was no significant difference in microleakage between two groups in the laser/acid corrosion joint group(P>0.05).It can be considered that there was no significant difference in the microleakage value of Er:YAG laser with different energy densities.2.The mean values of acid etching group,laser group and laser/acid etching combined group were(212±5.099)s,(72.75±3.694)s and(238.63±3.923)s.In the process of pit and fissure sealant,the mean value of laser operating time alone was the smallest and that of laser/acid etching dental surface treatment was the largest.One way ANOVA showed that there was significant differences among acid etching group,laser group and laser/acid etching combined group(P<0.05).Conclusion:1.The marginal adaptability of laser etching was similar to acid etching,but the effect of Er:YAG laser etching with different energy densities on the micro leakage value of pit and fissure sealant is not significant.2.Compared with Er:YAG laser etching,the marginal adaptability of Er:YAG laser etching combined with acid etching was better.3.Compared with traditional acid etching technology,Laser etching simplify the clinical operating process of pit and fissure sealant,reduce the operating time to some degree.It is suitable for young children with poor coordination.