The last solution used in root canal treatment to avoid painful surgical emphysema before dressing is
**Core Concept**
The question is testing the knowledge of the last solution used in root canal treatment to avoid painful surgical emphysema before dressing. This involves understanding the properties of various solutions used in endodontics and their effects on the periapical tissues.
**Why the Correct Answer is Right**
The correct answer is **B. Sodium Hypochlorite (NaOCl)**. Sodium hypochlorite is a strong alkaline solution that is commonly used in endodontics for its antimicrobial and solvent properties. It helps to dissolve organic matter and remove microorganisms from the root canal system. Before dressing, sodium hypochlorite is used to irrigate the root canal to remove any remaining debris and to prevent the formation of surgical emphysema, a condition characterized by the presence of air in the tissues surrounding the root canal.
**Why Each Wrong Option is Incorrect**
* **Option A:** **Water** is not an effective solution for pre-dressing irrigation as it does not have antimicrobial properties and may not effectively remove debris from the root canal.
* **Option C:** **Ethanol** is not typically used as a pre-dressing irrigant as it can be toxic to the periapical tissues and may cause inflammation.
**Clinical Pearl / High-Yield Fact**
When using sodium hypochlorite as a pre-dressing irrigant, it is essential to use it in a well-ventilated area and to avoid splashing the solution on the surrounding tissues to prevent irritation and inflammation.
**Correct Answer: B. Sodium Hypochlorite (NaOCl)**