Local anesthesia is used to prevent pain by making the area involved in the minor surgery numb. The area made numb is the one involved in pain during the procedure. Local anesthesia reduces pain without the patient’s awareness being changed. The area is made numb either by the application of local anesthesia i.e. the topical application or by injecting into the concerned area. In case of dental procedure usually a major nerve is anesthetized by injecting local anesthesia into it by proper techniques. At times several small injections need to be given in the concerned area and after few minutes the area is numb to precede with the minor surgical procedure. Extra local anesthesia can be given in order to make the area totally pain free. Usually the injection is also made painless by making the area of injection numb by the use of topical anesthetic. The effect lasts few hours depending upon the anesthetic used and the technique used.

Local anesthesia is commonly used to carry out painful dental procedures like the root canal treatment or minor surgical procedures.

Local Anaesthesia And Sedation In Dentistry

There are two main types of local anesthetics available and used in dentistry. One group is the amide group involving Lidocaine and the less used ester group involving cocaine, prilocaine etc. the ester group is less used these days due to the allergic reactions associated with them. Also the newer drugs are more effective and last for a longer time. The latest used local anesthetic in USA these days is the atricaine.

Local Anaesthesia And Sedation In Dentistry

The dental anesthetic used usually is a mixture of various agents serving various purposes

  1. A vasoconstrictor drug such as the adrenaline which causes the local anesthetic effect to last longer as the main effect due to the constriction of the blood vessels. Apart from this it also reduces the bleeding in the concerned area also.
  2. An anti-oxidant by the name of sodium metabisulphite is used to prevent the oxidation of the anesthetic agent and hence increase the shelf life of the vasoconstrictor.
  3. Methyl paraben is present as a preservative.
  4. An antifungal thymol is used
  5. Sodium chloride to maintain the iso-tonicity and distilled water as the carrier medium.

The main action site is the nerve membrane.

Generally there are two forms of local anesthesia injections which depend on the method of insertion of the needle by the dentist. The injection which numbs one whole region of the mouth like one side of the jaw is called as the nerve block. On the other hand an injection called as the infiltration is used to numb a smaller area. The numbness usually lasts longer in a nerve block.

Before giving the local anesthesia the dentist dries the area either with cotton swab or by lowing dry air. Some dentist applies the local aesthetic gel to numb the area before injecting the local anesthesia.

Usually a tingling sensation may be felt while the injection is being given. But as mostly taken to be the needle sting this feeling is actually occurring from the movement of the anesthetic through the pricked nerve.

Various procedures in dentistry cannot be made painless without the use of a local anesthetic and also at times the patient is so anxious with the fear of pain during the dental procedure that even if there is no need of an anesthetic injection they would purposely ask for it.

The procedures requiring local anesthesia in dental clinic are

1.   Cosmetic dentistry procedures
2.   Deep dental fillings
3.   Root canal treatment
4.   Removal of teeth
5.   Crown and bridge work
6.   Implants
7.   Periodontal gum surgeries

The availability of various anesthetic agents has made the dental procedures almost entirely painless.

The complications associated with the use of local anesthesia:

Properly used with proper quantity, quality and technique the complications caused by local anesthesia are almost none.

The feeling up heavy lip or numbness prevails for some time even afterwe leave the dental clinic. One can even find eating and talking also difficult. If anything is eaten before the numbness goes the lip can also be bitten without even the knowledge about it.

1.   When the needle pricks a blood vessel can result in the collection of the blood forming hematoma.

2.   The effect of the anesthesia outside the area to be operated causes the eyelid or the mouth to drop but the effects wear away with the usage of the anesthesia.

3.   The nerve if pricked by the needle it can lead to pain and numbness even after the effect of local anesthesia wears off and the symptoms disappear once the nerve regenerates.

4.   The vasoconstrictor in the local anesthetic makes the heart beat faster but this effect lasts for about 2 min so local anesthesia with adrenaline is avoided in cardiac patients.

5.   Trismus is another complication where if blood leaks due to a prick of blood vessel into muscle and gets fibrosed and the normal opening of mouth become difficult. The problem resolves after treatment.

6.   Allergic reactions are also seen to certain local anesthetic in some patients. As drug interactions occur the dentist should be told about the drugs being taken to avoid it.

Sedation can also be given in very apprehensive patients and certain difficult and painful dental procedures like the wisdom tooth impaction. Sedation is the process used to create an easy and relaxed anxiety Free State of mind through the use of sedative drugs like the tranquillizers, anti-anxiety drugs, nitrous oxide gas, depressants etc can be administered in different ways. Sedation is very commonly used in un-cooperative pediatric dental patients.

Local Anaesthesia And Sedation In Dentistry

The local anesthesia relieves pain but if administered after the sedatives the patient does not even feels the pain or apprehension of even the needle.

A term to be mentioned is the conscious sedation which is very popular in pediatric dentistry. The conscious sedation method puts the patient fast asleep but the conscious is not completely lost. It can be used for procedures ranging few hours. For major surgeries or treatments requiring long duration of time like multiple extractions, fixation of a fracture etc. general anesthesia is preferred. Very helpful in the treatment of a mentally challenged child also, nevertheless the general physician and the anesthetist should be consulted and the case approved by them before proceeding ahead with the dental treatment.

Local Anaesthesia And Sedation In Dentistry

So now with all these pain free options available you can easily go ahead with the any painful dental procedure also without any pain.

Leave Comment


  • Baigwa shem

    Baigwa shem 04 - August - 2015, at 01:25 AM

  • Doc.comment on the functions of the various components of saliva

  • brenda

    brenda 29 - June - 2012, at 12:19 PM

  • I had a filling done on my lower left side of the mouth. I got one injection at the very back left of my mouth, when it went in my left side felt like electricity was shocking my jaw. The dentist did the filling two times, (first time the filling was too close to the other tooth it would not let floss thru.) When I got home, I noticed my gums were cut up, I did salt rinses so I would not get infection. I'm not sure if I got an infection or something but now it's been two days, my left area of my jaw is very sore and every time I open my mouth wide I can feel the nerves pulling on my teeth, it is very uncomfortable. My left neck and shoulder have become very stiff. Please help I don't know what to do.

  • Sue

    Sue 25 - June - 2012, at 14:24 PM

  • I had a gum graft and the periodontist neglected to inform me of what type of graft he had performed. He told nothing about the procedure and what to expect in coming weeks and months. He also neglected to mention anything about what the long term effects of the anesthesia might be or any other information pertaining to the specifics of the graft. I had a free form gingival graft. I had to find out by searching on the internet. Secondly, he did not inform me that effects of the blocking may last up to 3-4 weeks. Symptoms included a hanging lower jaw, that felt like a lead weight had been inserted,a drooping, protruding swollen bottom lip, problems with my speech and excessive saliva, slurping and spitting. You can only imagine my panic. I was about to head to the ER, thinking severe and/or permanent nerve damage when a friend who works in a dental office was notified and kind enough to explain that in these surgeries, sometimes the effects of the blocking used in this rather invasive surgery is long term as in several weeks. Other details were also explained by "the friend" For shame on this periodontist. Yes, there will be an official complaint filed. Beware!

  • Dr.Ritz

    Dr.Ritz 02 - March - 2012, at 10:05 AM

  • There is no effect of local anesthesia on memory. There is no quoted study. The effect of local anesthesia is local. it is not systemic.

  • Christian

    Christian 01 - March - 2012, at 16:59 PM

  • I had almost weekly injections for a longer period of time. Does this local anesthesia's can effect your memory or lead later to brain loss. Is their any study out there?

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