Anesthesia has come a long way. Before general anesthesia existed, people might undergo surgery until they lost consciousness from the pain. For local anesthesia, people had plant extracts or alcoholic beverages rubbed on their gums. Happily, today's methods of anesthesia are very effective and don't involve more pain than they're trying to prevent.

Some research has focused on giving local anesthetics without needles. These systems aren't popular yet. But they are promising, says Donald Sadowsky, D.D.S. Dr. Sadowsky is professor emeritus of clinical dentistry and sociomedical sciences at Columbia University College of Dental Medicine and the Mailman School of Public Health.

One system consists of a patch applied to the gum. The patch contains a numbing drug. The drug enters the skin directly. After the patch is removed, a dentist can give a virtually painless injection at that spot.

Some people cannot tolerate numbing shots that go deep into their tissue. Instead, they can receive another type of shot. A tiny drill makes a hole in the gum. Then, a needle is inserted into the jawbone. Anesthetic is injected into the bone.

This type of anesthesia is somewhat uncomfortable to receive and not commonly used. But it numbs a large area of the lower jaw. It might not numb the gum tissue well enough to be used for removing teeth, says Dr. Sadowsky. But it can be used for fillings and root canals.

Besides local anesthesia, conscious sedation can be used. It is useful for people who are fearful or anxious. Sedative drugs reduce anxiety and fear. They also can cause short-term memory loss, so people don't remember most of the dental procedure. These medications can be taken as pills. They also can be injected into a vein. Many doctors also use nitrous oxide to reduce anxiety. Nitrous oxide is an odorless gas.