The Chronicles of Anesthesia

Stanley F. Malamed, DDS, joined the faculty of the University of Southern California School of Dentistry, Los Angeles, in 1973 where today he is professor of anesthesia and medicine. He has authored more than 120 scientific papers and 16 chapters in various medical and dental journals and textbooks in the areas of physical evaluation, emergency medicine, local anesthesia, sedation, and general anesthesia. In addition, Malamed is the author of three widely used textbooks. He speaks internationally on anesthesia and emergency medicine and is an editorial advisory board member for Dimensions of Dental Hygiene.

Q: What is the history of anesthesia usage in dentistry?

A: Prior to 1844, anesthesia did not exist, meaning that procedures involving surgery were only performed if their duration was very quick. In dentistry, this limited the field to extractions of teeth. In medicine, surgery was only used for the amputation of limbs. Due to the immense pain endured, these procedures were only attempted if the patient’s life was in danger. The use of anesthesia began in 1844 with the first use of nitrous oxide by Dr. Horace Wells, a Connecticut dentist, who had seen a demonstration of nitrous oxide at a science show. He thought the drug might be useful for pain control in dentistry. On December 11, 1844, Horace Wells was the patient to whom pure nitrous oxide was administered, rendering him unconscious and having one of his own teeth extracted painlessly. This was the beginning of anesthesia.

Ether and chloroform followed nitrous oxide. Then general anesthesia became possible and surgery, both in dentistry and medicine, evolved. By 1885, general anesthesia had become an accepted technique, however, it was the only technique available to a patient for pain control. In 1886 in Vienna, Austria, Sigmund Freud and Carl Koller, both physicians, used topically applied cocaine for the first time to produce anesthesia for surgery on a conscious patient. In 1886 in Baltimore, Md, a medical doctor, William Halsted, administered cocaine with epinephrine by injection, giving an inferior alveolar nerve block. As a result, cocaine with epinephrine became known as a wonder drug because it was the only drug available that allowed a patient to undergo surgery without pain and remain conscious.

By 1904, some of cocaine’s side effects became obvious. Addiction was one, not with patients but amongst the doctors who administered it. Also because cocaine is a cardiovascular stimulant, some patients would receive an injection of cocaine with adrenaline and then die of cardiac arrest in the dental office.

Q: How did Novocain come about?

A: In 1904 in Germany, Alfred Einhorn synthesized a drug called procaine, which was introduced under the brand name Novocain. Novocain is chemically related to cocaine but doesn’t have some of the negative properties. Novocain became almost instantly the most popular local anesthetic in the world. From 1904 to 1948, procaine and drugs related to it—the ester type—were extremely popular and very safe.

Procaine with epinephrine produces anesthesia for approximately 10 minutes. In the early 1900s, dental procedures were done using a quick-pedal handpiece so the duration of appointments was quite short, which made reliance on procaine a good choice at the time. Procaine was a slow-acting drug and didn’t produce a profound anesthesia. It wasn’t consistently reliable and many people became allergic to it. So in 1948, a Swedish company synthesized a very different chemical, which was chemically unrelated to esters. This drug was lidocaine and was introduced under the brand name Xylocaine in 1948. Lidocaine is the first in the family of amide local anesthetics.

Q: What are the major differences between procaine and lidocaine?

A: Lidocaine has a much faster onset and a longer duration. It’s more profound and more consistent. Almost immediately, dentists loved it. And by the early 1950s, the amide local anesthetics were the drugs of choice and esters began to fade into history. In the 1950s, a second amide named mepivacaine, brand named Carbocaine, was introduced. In 1965, prilocaine (Citanest) was introduced.

So by the mid-’60s, dentists in America and worldwide had three good amide local anesthetics: lidocaine, mepivacaine, and prilocaine. With the addition of epinephrine, all provided the dental patient and the dentist with about 1 hour’s worth of pulpal anesthesia and 3-5 hours of soft tissue anesthesia. The first dental implants were placed and a longer duration of anesthesia was needed. Not just for longer procedures in the office, but also for post-surgical pain control.

In 1983, bupivacaine or Marcaine was introduced in the United States in dental cartridge form. Bupivacaine is the first of the long-acting local anesthetics. Bupivacaine, along with epinephrine, provides the patient with pulpal anesthesia ranging anywhere from 90 to 180 minutes and soft tissue anesthesia ranging from 3 to 12 hours. It is the most popular, long-acting anesthetic used primarily in dentistry today mostly for post-surgical pain control.

In 2000, the last of the current anesthetics, articaine, was introduced in the United States. The brand names are Septocaine and Zorcaine. Articaine has been available in Europe since 1973 and was introduced in Canada in 1983. Articaine with epinephrine is a drug that is very similar in clinical properties to lidocaine, mepivacaine, and prilocaine. It provides approximately 1 hour of pulpal anesthesia and about 3-5 hours of soft tissue anesthesia.

Q: What is articaine’s role in the local anesthetic armamentarium?

A: The amide local anesthetics, such as lidocaine, were created in response to procaine’s shortcomings. By the 1940s, dentists were unhappy with Novocain’s short duration, slow onset, and lack of consistency. The newer drugs, the amides, were faster acting with longer duration, more profound anesthesia, and more consistently reliable. Administered by infiltration over a maxillary lateral incisor, pulpal anesthesia would develop in 99 of 100 cases. Now and then, of course, a block is missed or a patient is seen who is simply difficult to get numb.

Then in the 1980s, word came to the United States about a local anesthetic available in Europe and Canada that was said to work faster, better, and was more reliable than the amides. This drug is articaine, now available under the proprietary names Septocaine and Zorcaine.

Dental local anesthetics are a very small market for pharmaceutical companies. Most are reluctant to spend the tens of millions of dollars required for the research and development of a new drug to get it approved for sales by the Food & Drug Administration (FDA). The phase III clinical trials (demonstrating the drug’s safety and efficacy) on articaine were done in the late 1990s in both the United States and the United Kingdom in 29 clinical sites. In June of 2000, the FDA gave its approval for the sale of articaine in the US dental market.

So today, in the year 2006, dental hygienists in North America have four local anesthetics to choose from: articaine, lidocaine, mepivacaine, and prilocaine. These drugs provide, with the addition of a vasoconstrictor, 1 hour of pulpal anesthesia (and 3 to 5 hours of soft tissue anesthesia). For a shorter duration, mepivacaine 3% (plain) is suitable as is prilocaine 4% (via nerve block only). On the very rare occasion when a hygienist requires a prolonged duration of anesthesia (up to 12 hours) bupivacaine 0.5% with epinephrine is available.

From Dimensions of Dental Hygiene. January 2006;4(1):22-24.