The main role of sodium hypochlorite (NaOCl) irrigation during root canal therapy is to dissolve organic tissue remnants and disinfect the root canal system.

- Sodium hypochlorite is widely used as an irrigant because of its powerful antimicrobial properties and its ability to break down necrotic tissue, biofilms, and organic debris within the complex anatomy of the root canal.
- This helps in reducing bacterial load and ensures a cleaner canal space, which is essential for successful root canal treatment.

To clarify the options given:
- Option 1 (Remove inorganic smear layer): Sodium hypochlorite is not effective in removing inorganic components of the smear layer. For this purpose, chelating agents like EDTA are used.
- Option 3 (Enhance adhesion of root canal sealers): This is not a primary function of sodium hypochlorite. Adhesion is more related to the properties of the sealer and surface treatment.
- Option 4 (Neutralize acidic byproducts): Sodium hypochlorite does not serve this function.

Therefore, the primary and most critical role of sodium hypochlorite irrigation is to dissolve organic tissue remnants and disinfect the root canal system.

Reference: Hargreaves KM, Cohen S. *Cohen’s Pathways of the Pulp*, 12th Edition, Volume 1, Chapter 8: Root Canal Irrigation and Disinfection / Page 280-290