an in vitro comparison of coronal microleakage of three orifice barriers filling materials

introduction: a coronal barrier in root-filled teeth is one of the most effective methods for prevention of coronal microleakage. the aim of this study was to compare coronal microleakage of three materials [light-cured glass-ionomer (gi), mineral trioxide aggregate (mta), and composite resin] as coronal barriers. materials and methods: a total of 188 intact maxillary incisors were used. after instrumentation, all the canals were obturated with gutta-percha and lateral condensation technique using ah26 sealer. then, the teeth were sectioned just apical to the cemento-enamel junction. the roots were randomly assigned to three experimental groups ( n =56) and two negative and positive control groups ( n =20). after placing the orifice barrier, the samples were immersed in 2% methylene blue solution for 2 weeks at 37 ° c. then the teeth were longitudinally sectioned mesiodistally and dye penetration was measured under a stereomicroscope at ×10 magnification. data were analyzed with one-way anova and a post-hoc tukey test. results: the positive control group leaked significantly more than all the experimental groups ( p =0.001). mta exhibited less leakage than composite and gi ( p =0.002) but no significant differences were found between gi and composite groups. conclusion : immediate placement of a suitable intra-orifice barrier like mta, before final restoration, may help minimize recontamination of the remaining apical gutta-percha.