Introduction: Sealing of the root canal entrance is an effective method of reducing microleakage in endodontically treated teeth. Although studies support the effectiveness of coronal barriers (CB), there is no universal protocol that incorporates it as part of the Endodontic Treatment. Objectives: In order to assess what is the best material to be udsed as CB, when applied on the entrance of the root canal after filling, an in vitro micro-leakage study was carried with four materials. Materials and Methods: 70 single root teeth were aleatory divided into 4 test groups (n=15) and 2 control ones (n=5). The materials tested were Ionoseal®, GC Fuji II LC®, GrandioSO® Flow and GrandioSO®. The teeth were subjected to thermal cycling and then immersed in a methylene blue dye 2% for leakage evaluation. The results were analysed using ANOVA and Tukey HSD statistic testes (α = 0.05). Results: Overall, Ionoseal® showed the greater amount of leakage and, compared to the other groups, the difference was statistically significant (p0.05). However, between GC Fuji II LC® , GrandioSO® Flow and GrandioSO®, there was no statistically differences. Conclusion: The results showed that LC Fuji II®, GrandioSo® Flow and conventional GrandioSo® are suitable as intra-canal barrierrs, promoting a CB to infiltration. When using Ionoseal®, its suggested the use of adhesive system to improve the sealing; in future, more studies are needed to analysed the behave of this material. Clinical Implications: Sealing of the root canal is essential suggesting their integration into routine clinical protocol. Schlagwörter: coronal sealing, coronal barrier, endodontic sealing, endodontic infiltration, endodontic leakage, micro-leakage, canal reinfection