Study On The Effect Of Different Root Canal Irrigation Schemes On Apical Sealing Ability

Objective To investigate the effect of several root canal irrigation schemes commonly used in clinic on apical sealing of single root canal teeth after iRoot SP + continuous wave of condensation technique,in order to select a more compatible root canal irrigation scheme with iRoot SP.Methods According to the experimental inclusion criteria,90 newly extracted single root canal isolated teeth were collected from the oral and maxillofacial head and neck surgery outpatient department of our hospital from June 2017 to December 2017,due to the need of orthodontic treatment.All the isolated teeth were treated with protaper combined with crown downward technique for root canal preparation.According to the different irrigation schemes,they were randomly divided into six groups,with 15 extracted teeth in each group.Experimental group A: the basic and final rinse solutions were 2.5%NaClO.Experimental group B: the basic rinse solution was 2.5% NaClO,and the final rinse solution was 17% EDTA.Experimental group C,the basic rinse solution was 17% EDTA,and the final rinse solution was 0.2% chlorhexidine(CHX).Experimental Group D: the basic rinse solution was 2.5% NaClO,and the final rinse solution was MTAD.Positive control group E and negative control group F: both basic and final rinse solutions were distilled water.All extracted teeth were rinsed with syringe method.During the mechanical preparation of root canal,the instruments were replaced once for basic irrigation.The total washing time and residence time was 60 s,and the dose was 1 ml.After the last mechanical preparation of the root canal,the final was carried out.The washing time and residence time were 5 min in total,with a dose of 5ml.After the final washing,the single sterile moisture absorbent paper tips were placed in the root canals of extracted teeth in each group for 30 s to dry the root canal.The root canal was filled with iRoot SP+ continuous wave of condensation technique,and the crown was filled with zinc phosphate cement base and resin layered filling.After that,all the teeth in vitro were placed in the incubator with temperature of 37 C and humidity of100% for one week,and then the materials were fully cured.After 1 week,the extracted teeth in the experimental group and the positive control group were sealed with transparent nailpolish in the area of the whole tooth tissue except for the root tip of 2mm.The negative control group were sealed the whole tooth tissue,including apical foramen.Finally,apply dye microseepage experiment and clearing technique specimen method were used to treat all extracted teeth.The effects of different root canal irrigation schemes on apical closure were evaluated by measuring the length of dye infiltration into root canals under stereomicroscope.The measured data were expressed as mean standard deviation,and the data were analyzed by statistical software SPSS21.0.The test level was =0.05,P<0.05,and the difference was considered statistically significant.Results(1)There was no dye infiltration in the root tip area of the negative control group,and the dye infiltration distance was 0;(2)The dye infiltration distance of the positive control group was greater than that of the experimental group,and the difference was statistically significant(p<0.05).(3)The dye infiltration distance of each experimental group was different,and the difference was statistically significant(p<0.05).Further pairwise comparison showed that the dye infiltration distance of group A was significantly larger than that of group B and D,and the difference was statistically significant(p<0.05).Dye infiltration distance in group C was significantly greater than that in group B and D,and the difference was statistically significant(P<0.05).There was no significant difference between group A and group C(P>0.05).There was no significant difference between group B and group D(P>0.05).Conclusion(1)The extracted teeth can be effectively sealed by transparent nail polish to prevent microleakage;(2)Combined with the application of chemical rinse solution during root canal preparation,the sealing property of single root canal tip after iRoot SP+ continuous wave of condensation technique can be improved.(3)The solutions of group B(2.5% NaClO+17%EDTA)and group D(2.5% NaClO+MTAD)had better sealing effect on the root tips of single root canals after iroot-sp + continuous wave of condensation technique.(4)The solutions of group A(2.5% NaClO+2.5% NaClO)and group C(17%EDTA+0.2%CHX)were followed by the sealing of single root canal root tips after iRoot SP+ continuous wave of condensation technique.