In Vitro Evaluation On Sealing Ability Of IRoot BP Plus Used As Apical Barrier Technique

Objective To evaluate the apical sealing ability and marginal adaptation to the root canal wall of the new bioceramic material iRoot BP Plus for apical barrier technique,and to compare it with MTA for clinical application and promotion of iRoot BP Plus.Methods Thirty-nine newly single-rooted extracted teeth were collected according to the inclusion criteria,and the crowns were removed and preserved the remaining root length was 13 mm.All canals were prepared up to F3 with Protaper rotary device using a crown-down technique.The apices were then prepared using 1#(d=0.5mm),2#(d=0.7mm)and 3#(d=0.9mm)Gates-Glidden bur in sequence to form an open apical state of 4mm in depth.All teeth were randomly divided into group A(n=18),group B(n=18)and negative control group(n=3)according to the different apical barrier materials.group A was filled with MTA apical barrier + high temperature thermoplasticized injectable technique;group B was filled with iRoot BP Plus apical barrier + high temperature thermoplasticized injectable technique;negative control group was filled with continuous wave condensation technique,After all teeth were filled,the crowns were temporarily sealed with ZOE cement and placed in a 37°C,100% humidity incubator for 1 week.Three samples were randomly selected from each of groups A and B,cut longitudinally along the long axis of the tooth through the apical foramen,and placed under a scanning electron microscope(SEM)to observe the fit of the two materials with the root canal wall.The remaining 15 samples from each of the two groups were coated with two layers of clear nail polish except for the apical 2 mm,and all the samples from the negative control group were coated with two layers of clear nail polish including the apices,and after complete drying,a glucose leakage model was established to detect the amount of glucose leaking from the coronal side through the apical foramen on days 1,7,14,21 and 28,respectively.The t-test of two independent samples was used for statistical analysis,and P<0.05 was considered statistically significant.Results 1.Glucose leakage experiment: During the observation period,the amount of glucose leakage in group B(iRoot BP Plus group)was lower than that in group A(MTA group)at each testing time point,and the difference between the two groups was statistically significant(P<0.05).2.Scanning electron microscopy observation: In group A,there was an microleakage between the MTA barrier and the root canal wall dentin.In group B,the iRoot BP Plus barrier was more closely bonded to the root canal wall dentin,no significant gap was seen,and the marginal adaptation was better.Conclusion The apical sealing ability and marginal adaptation of iRoot BP Plus for apical barrier technique is better than that of MTA,which can compensate for the disadvantages of MTA in terms of difficult clinical operation,causing tooth discoloration and high cost,and has potential clinical application and promotion prospects.