Aim:The aim of this study is to evaluate and compare the sealer penetrability and gap formation of root canal sealer to root dentin filled with AH Plus, Sealapex, and BioRoot RCS. Materials and methods: Twenty-seven mandibular second premolars were selected and were radiographed at two angulations. The teeth were stored in labeled plastic vials containing artificial saliva and were randomly assigned to three groups based on the sealer, group I-AH Plus (n = 9), group II-Sealapex (n = 9), and group III-BioRoot RCS (n = 9); teeth were de-coronated and the conventional root canal therapy was done with Protaper gold rotary files. Three groups were filled with AH Plus, Sealapex, and BioRoot RCS with the single-cone technique. About 1-mm sections of apical, middle, and cervical third were taken using a water-cooled low-speed saw. All specimens are evaluated using a scanning electron microscope. Clinical significance: The main goal of obturation is to provide a three-dimensional seal, thereby preventing the reinfection of the root canal and preserving the health of periapical tissues. Because of the hydrophobic nature of gutta-percha, the sealer tends to pull away from gutta-percha on the setting. To overcome these drawbacks, new sealer systems have been introduced to enhance the sealing ability. Resin-based sealers have gained more popularity in recent years because these sealers penetrate deep into the dentinal tubules due to their better flowability, long setting time, and provide long-term dimensional stability. The resin-based sealer used in this study is the AH Plus. It is compared with the newly introduced bioceramic sealer BioRoot RCS for marginal adaptation. Results: It was found that the AH Plus group had a higher depth of sealer penetration than other groups and the BioRoot RCS group revealed a minimum gap formation than other groups of sealers evaluated in the study. Conclusion: The Bioceramic sealer revealed better sealer penetrability at the apical third and minimal gap formation compared to the epoxy resin-based and the calcium hydroxide-based sealer.