Experimental Study On Antibacterial And Adhesive Properties Of Lanthanum Chloride Orthodontic Adhesive With Different Proportion

Objective In this study,different proportions of Lanthanum chloride were added to the light curing enamel adhesive resin,in order to test the antibacterial effect of Lanthanum chloride on Streptococcus sobrinus.Compared with the adhesive resin without Lanthanum chloride in antibacterial and adhesive properties,it provides a new idea for the prevention of caries in orthodontic treatment process.Methods 1%,2%,3%,4%and 5%Lanthanum chloride were added into the light cured enamel adhesive resin as the experimental group of group A,B,C,D and E respectively,and the adhesive resin without Lanthanum chloride as the control group of group F.The six groups of resins were made into test pieces with a diameter of 6 mm and a thickness of 1 mm.The antibacterial properties of the six groups of test pieces were tested by the bacteriostatic ring method and the OD value of bacterial liquid measurement method.5%Lanthanum chloride orthodontic adhesive resin and Resin-modified glass Ionomer cements?RMGIC?were immersed in distilled water for 0 h,48 h and 1w respectively,and their antibacterial properties were tested and compared by the OD value of bacterial liquid measurement method.60 non carious premolars extracted by orthodontic treatment were randomly divided into six groups on average.The orthodontic brackets were bonded to the center of the crown with the light curing enamel adhesive resin of group A?F,and 60 detached teeth were separately embedded in the self setting plastic.The adhesive strength was measured by universal mechanical testing machine.After bracket debonding,the adhesive residue index?ARI?was scored,and the fracture position of adhesive resin was analyzed.Results There was no bacteriostatic ring in the experimental group and the control group.The OD₅₄₀value of the bacterial liquid in the experimental group A?E group decreased gradually,and the OD₅₄₀value of group E was the smallest.The difference of OD₅₄₀between group A?E and group F was statistically significant?P<0.05?.There was no significant difference between OD₅₄₀of group A and group B,group B and group C?P>0.05?,and there was significant difference between the other groups?P<0.05?.OD₅₄₀of group RMGIC without distilled water immersion was less than group5%Lanthanum chloride,and the difference was statistically significant?P<0.05?.OD₅₄₀of group RMGIC was higher than that of group 5%lanthanum chloride after 48 hours of immersion,and the difference was statistically significant?P<0.05?.While OD₅₄₀of group RMGIC and group5%Lanthanum chloride had no significant difference?P>0.05?after 1 week of immersion.OD₅₄₀of bacterial liquid increased gradually with the increase of immersion time,and there was significant difference between group5%Lanthanum chloride and group RMGIC?P<0.05?.With the increase of the proportion of Lanthanum chloride,the shear strength of group A?E in the experimental group showed a downward trend,while that of group F in the control group was the largest.The difference of the shear strength between group A?E and group F was statistically significant?P<0.05?,and the difference between groups A?E in the experimental group was not statistically significant?P>0.05?.There were only 4 samples with a ARI score of"0"and 19,21 and 16 samples with ARI scores of"1,2 and 3"respectively.There was no significant difference in ARI scores between group A?F?P>0.05?.Conclusion The light curing enamel adhesive resin with 5%Lanthanum chloride has obvious antibacterial effect on Streptococcus sobrinus.During 48 hours,the antibacterial activity of 5%lanthanum chlorideadhesive resin was lower than that of RMGIC.After 48hours,the antibacterial activity of 5%lanthanum chlorideadhesive resin was stronger than that of RMGIC.One week later,both two kinds of adhesive resinalmost lost their antibacterial activity.Adding 1%?5%Lanthanum chloride in different proportion to the light curing orthodontic adhesive.Although the shear strength is reduced,it is within the range of clinical acceptance?7-9MPa?.The addition of Lanthanum chloride did not increase the risk of enamel damage.