Which of the following agents is primarily used for sedation during dental procedures?

The agent primarily used for sedation during dental procedures is laughing gas, which is also known as nitrous oxide. This inhaled sedative is commonly utilized in dentistry to help patients relax while remaining conscious and able to respond to instructions. Nitrous oxide works quickly and provides a calming effect, making it ideal for various dental procedures, especially for patients who may experience anxiety or fear associated with dental treatments.

In contrast, local anesthetic is used to numb a specific area of the mouth to prevent pain during dental procedures, but it does not provide sedation or alleviate anxiety. Epinephrine is often combined with local anesthetics to prolong their effect and reduce bleeding, but it does not serve as a sedative agent. Ibuprofen is a non-steroidal anti-inflammatory drug that is used to relieve pain or inflammation, but it does not have sedative properties and is not used for sedation in dental settings. Thus, laughing gas is the agent of choice for sedation, facilitating a more comfortable experience for dental patients.