The Effect Of Smear Layer On Apical Microleakage After Retrograde Filling

Retrograde filling technique (Retrograde filling) is an important step in apical surgery, those patients who are have situations such as the root canal calcified, severely curved root canal, root canal barrier and so on can not routine root canal treatment and want to keep the teeth, through the retrograde filling can close the outside down to prevent bacteria and periapical inflammatory substances penetration and expand the indications for teeth to maintain the physiological function of teeth to improve the quality of life of patients. However, retrograde preparation will produce the smear layer, the so-called retrograde preparation of the smear layer is produced in retrograde preparation, due to the use of high-speed burs, and instantly generating a lot of heat can cause the root canal wall organic degeneration, and dentin debris, dentin tubules exudate, saliva and bacteria in the root canal paste admixture also play the roles. the smear layer is very difficult to flush out by ordinary fluid and affects apical root filling material and the inner wall of adaptation, which leads to apical microleakage. Many experts have different views about the removal of the smear layer or smear layer retained.This experiment is to study whether to keep the smear layer or not after retrograde filling, removal of the smear layer and smear layer retained a comparative study, to observe the apical microleakage, provide a theoretical basis for clinical practice.ObjectiveThrough 36 preparations of isolated teeth fell down after the smear layer produced in the apical dye penetration microleakage cases, observe whether microleakages impact the results. MethodsChoose 36 human single-rooted canal teeth,prepare the root canal,fill the lateral root by the step-back technique . The teeth were randomly divided into two groups 18, the experimental group: 17% of the ethylene amine tetraacetic acid (EDTA) +1% Naclo+10% Citric acid washed root tip to the set after the removal of smear layer, the control group without any fluid flush, end filling with glass ionomer root tip, stained by the dye penetration method, made of demineralization dehydration transparent teeth in the experimental group. two groups photographed under a microscope and measure the depth of staining, statistical analysis and comparison of two sets of differences by t test.ResultsThe experimental group and control group in the incubator (37°C) were observed the depth of dyeing after one week, both have the existence of micro leakage, but the experimental group are stained less than the control group .Conclusion(1) Both the experimental group and control group had microleakages.(2)experimental group (2.88±0.68) apical microleakage got less microleakage than the control group (3.38±0.77).