Aim: The present study aimed to evaluate the sealing potential and marginal adaptation of different root canal sealers to dentin. Materials and methods: A total of sixty human lower premolars of the permanent dentition that were extracted were used for this study. The visible debris and calculus were removed from the extracted teeth ultrasonically and were kept for 2 hours in 2.5% sodium hypochlorite and stored in normal saline till next use. A low-speed diamond disc was used to section all the teeth samples at the cementoenamel junction. Later, cleaning and shaping of the canals was done. Based on the sealer used, the samples (each group consisting of 20 samples) were divided randomly into three groups: group I-bioceramic sealer, group II-resin-based sealer, group III-MTA-based sealer. All split samples were visualized under scanning electron microscope (SEM) at apical and coronal thirds of root canal, the marginal gap at root dentin and sealer interface were assessed. Results: The highest marginal adaptation (5.60 ± 0.12) was demonstrated by EndoSequence BC sealer, followed immediately by ProRoot MTA sealer (4.48 ± 0.12) and EndoREZ sealer (2.10 ± 0.54). A statistically significant difference (p = 0.001) was seen between the EndoSequence BC and ProRoot MTA sealer for apical and coronal marginal adaptation. Also, a statistically significant difference (p < 0.05) was found between EndoSequence BC sealer vs EndoREZ sealer at coronal and EndoSequence BC sealer vs EndoREZ sealer and EndoREZ sealer vs ProRoot MTA sealer at apical third. Conclusion: The present study concluded that significant and better sealing ability and marginal adaptation was demonstrated by EndoSequence BC (bioceramic sealer) when compared to ProRoot MTA sealer (MTA-based sealer) and EndoREZ sealer (resin-based sealer). Clinical significance: Numerous endodontic sealers enter the market with various factors to attain acceptable seal. According to current study bioceramic sealer, is the appropriate sealer that hermetically seals all the margins.