Dental Anaesthesia

In the practice of medicine (especially surgery and dentistry), dental anaesthesia or anaesthesia is a state of temporary induced loss of sensation or awareness.

There are different types of anaesthesia that Oral Health Care Professionals use:

Local anaesthesia

The most common is local anaesthesia, given to numb the area or tooth that the dentists will work on. On the upper teeth, the anaesthetic numbs the nerve as it branches out to the individual tooth or area. In the lower jaw, however, the nerve supply is slightly different. To numb any area or tooth, the main nerve, inferior dental nerve, is numbed. 
Both of the above methods are commonly used for all dental procedures, from fillings to Oral Surgery and Dental Implants.

Anaesthetics, then and now

Cocaine was a popular anaesthetic in the 19th century. Novocaine (Procaine), which is cocaine derivative,  was the next alternative in 1905. It’s better than cocaine as it’s not toxic, lats longer and is not addictive. Lidocaine (Xylocaine) became popular in 1947. Then came Prilocaine in the 1950’s, then Articaine (Ultracain) in 1976 and finally Scandicaine (Scandonest).

The most commonly used local anaesthetic is lidocaine (also called xylocaine or lignocaine). It’s a modern replacement for novocaine and procaine. Its half-life in the body is about 1.5-2 hours, but this can vary from patient to patient. Anaesthetic “wears off” by being metabolized. So it takes a few hours. The more you work that muscle (talk, chew, etc) the faster it will wear off. If you went home and took a nap, it would most likely still be numb when you woke up.

Most agents come in two forms: with and without epinephrine.


Intravenous Sedation – a conscious sedation that works on the central nervous system. Helps to reduce the anxiety of the patient when undergoing dental treatments.
The Oral Health Care Professionals will administer a drug called midazolam into the vein to help relax the patient. The effects can last for approximately 24 hours after the treatment. Although the patient is sedated, the dentists will use local anaesthesia on the area that he will work on.  

Some dental practices use terms such as “sleep dentistry” or “twilight sleep” when talking about IV sedation. This is confusing because it suggests that IV sedation will put people to sleep. These terms are more descriptive of deep sedation. Deep sedation is not common (in the U.K. at least) and is classified as general anaesthesia (even though sedation occurs on a continuum).

In reality, you remain conscious during conscious IV sedation. You will also be able to understand and respond to requests from your dentist.
However, you may not remember much (or anything at all) about what went on. Since IV sedation induces a state of deep relaxation and distraction from surroundings.

The drugs that doctors use for IV sedation produce either partial or full memory loss (amnesia). But only for the period of time from when the drug first kicks in until it wears off. As a result, time will appear to pass very quickly and you will not recall much of what happened. Many people remember nothing at all. So it may appear as if you were “asleep” during the procedure.

General anaesthesia

Professionals in hospitals mainly use it for complex  Oral Surgery and Dental Implants and the extraction of multiple teeth. General anaesthesia involves administering one or more general anaesthetic drugs to render the patient unconsciousness. It also results in a loss of protective reflexes. General anaesthesia may have side effects such as amnesia, analgesia, relaxation of skeletal muscles, and loss of control of reflexes of the autonomic nervous system.

GA can be useful in certain situations

  • Conscious IV sedation works for about 97% of extremely anxious people. But there will always be a few people for whom it doesn’t work. Either because you find it impossible to cooperate even when sedated and/or because you have a very high tolerance to the drugs used for IV sedation. This appears to be more common if you’ve been taking similar drugs long-term for other mental health conditions. In this case, GA may be the best option.
  • For short or longer potentially traumatic procedures. For example, removal of wisdom teeth or certain other types of oral surgery. While there may be alternatives to multiple shorter appointments, in some cases GA may be preferable. If it’s extractions that really terrify you, the dentist may put you to sleep. The rest of the care for Dental problems and treatment (fillings etc.) can be done under conscious sedation with a local anaesthetic.