`N_2 O` is used as an anesthetic in dental surgery.

Answer

**Step-by-Step Text Solution:**

1. **Understanding N2O**: The chemical compound nitrous oxide, commonly referred to as N2O, is a colorless gas with a slightly sweet odor and taste. It is often used in medical settings.

2. **Role of N2O in Anesthesia**: N2O is primarily used as an anesthetic due to its ability to induce sedation and relieve pain. It is classified as a general anesthetic and is particularly effective for procedural sedation.

3. **Mechanism of Action**: When inhaled, nitrous oxide interacts with the central nervous system. It alters the perception of pain and can induce a state of euphoria, making it easier for patients to undergo dental procedures without experiencing severe discomfort.

4. **Application in Dental Surgery**: In dental surgery, N2O is used to manage anxiety and pain. It allows patients to remain conscious and responsive while still providing significant pain relief, making it ideal for various dental procedures.

5. **Additional Uses**: Besides dental surgery, nitrous oxide is also used in emergency departments for quick pain relief and sedation in various medical situations.

6. **Conclusion**: The use of N2O in dental surgery is primarily due to its effectiveness in providing pain relief and sedation, making it a valuable tool for dentists and patients alike.

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