Laughing at the drill.

• Position: Use of nitrous oxide in dentistry

Nitrous oxide, or laughing gas, helps many dental patients maintain a more lighthearted attitude than they otherwise might as they peer at a drill headed straight for their molars. "Nitrous oxide allays feelings of apprehension and allows patients to become more calm and relaxed, thus reducing any stress associated with a trip to the dentist," notes Steven Sullivan, an oral and maxillofacial surgeon at the University of Oklahoma Health Sciences Center. "Although the patient always retains consciousness, hearing, sight, touch, and pain, memory, concentration, and calculation are temporarily affected, and most people get a little |giddy' under its influence. The term |laughing gas' was a direct offshoot of some of the clinical observations of its effects."

In 1868, dentists introduced oxygen with nitrous oxide and it has been used with general anesthesia ever since. One of the primary benefits is that patients can breathe room air whenever they choose, thus regulating the level of analgesia. "Instead of being rendered unconscious, patients are rendered fearless and time seems to pass very rapidly. At least 50% of all pain involved in dentistry can be eliminated by doing away with fear, anxiety, and the anticipation of pain - all of which nitrous oxide does."

While many people take its application for granted, not many know about the actual gas itself. Sullivan offers answers to some frequently asked questions:

Does it have any long-term effects? Since nitrous oxide is a soluble gas, it usually diffuses rap through the body with little...