**Question:** After more than 1 hour of extraoral time, an avulsed tooth is soaked in sodium hypochlorite solution, then it should be soaked in:

A. Whole milk
B. Saline solution
C. Blood
D. Dental stone

**Core Concept:** When an avulsed tooth is reimplanted, it is essential to preserve its viability by maintaining its tissue perfusion and preventing bacterial contamination. After extraoral time exceeds 1 hour, using sodium hypochlorite solution for initial irrigation helps to eliminate any residual bacteria and tissue debris, making the tooth suitable for further treatment.

**Why the Correct Answer is Right:** Sodium hypochlorite solution (e.g., household bleach) is an effective antimicrobial agent that helps to eliminate potential pathogens and tissue debris from the root canal system. This makes the tooth more suitable for reimplantation or further treatment.

**Why Each Wrong Option is Incorrect:**

A. Whole milk (fatty substances, proteins, and carbon dioxide can be detrimental to the tooth's viability and tissue perfusion).
B. Saline solution (does not have the antimicrobial properties of sodium hypochlorite solution, making it less effective in eliminating potential pathogens).
C. Blood (contains coagulation factors and platelets, which could potentially clog the root canal system, impairing tissue perfusion and tooth viability).
D. Dental stone (is an inert substance, not suitable for disinfecting the root canal system and maintaining tissue perfusion).

**Clinical Pearl:**

To ensure optimal treatment outcomes for an avulsed tooth, the following steps should be followed:
1. Apply sodium hypochlorite solution for initial irrigation (to eliminate bacteria and tissue debris).
2. After the initial irrigation, reimplant the tooth immediately or proceed to further treatment options like transport media (such as saline or heparinized saline) and maintain constant moisture and temperature to preserve the tooth's viability.
3. Consult a dental professional for proper evaluation, reimplantation, or treatment options.

**Correct Answer:** B. Saline solution (sodium chloride solution)

**Why the Correct Answer is Right:** Saline solution (sodium chloride solution) is commonly used as a transport medium for avulsed teeth, as it helps to preserve the tooth's viability by maintaining constant moisture and temperature. It is also free of blood products, reducing the risk of clot formation within the root canal system.

**Why Each Wrong Option is Incorrect:**

A. Whole milk (as mentioned above)
B. Blood (contains clotting factors that could clog the root canal system and impair tissue perfusion)
C. Dental stone (inert substance, not suitable for disinfecting the root canal system)
D. Sodium hypochlorite solution (used for the initial irrigation, not for transport media)