Dental anesthetic nerve damage – What is the cause?
Dental anesthetic nerve damage after administering dental anesthetic is a known risk factor, although it is very uncommon. The exact cause may never be known because multiple things are happening at once, physical and chemical trauma.
Dental anesthetic nerve damage recovery rates
Temporary paresthesia occurs in around 1 in 6000 IANBs and is much more common than anything permanent, which occurs in about 1 in 30,000 IANBs. However, since the vast majority of cases go away on their own the reported rate of dental anesthetic nerve damage is likely much higher than reported. More than 80% with temporary damage will recover within 3 months, usually in the first 2 weeks. Another stat I have seen states 85% recovery in 8 weeks or less. After that time period about 1/3 do not recover. Some say their is no benefit to microsurgery, but that is debatable.
What is the cause of dental anesthetic nerve damage?
There exists three major theories on the cause of this nerve injury. Lingual nerve damages occurs about twice as often as IAN damage. Unfortunately around 1/3 of patients will experience dysesthesia.
- Direct trauma to the nerve from the needle itself.
- Intra-neural hematoma formation.
- Local anesthetic toxicity.
What is the treatment for dental anesthetic nerve damage?
There is no known treatment for nerve damage resulting from dental anesthetic. Steriods and anti-inflammatory are often used for treatment, but there is no evidence they are beneficial.
Which dental anesthetics are more likely to cause nerve damage?
It appears that the higher percentage anesthetics can cause local anesthetic toxicity that results in dental anesthetic nerve damage. The approximate rate at which it happens overall is around 1:785,000. Such a low rate makes it difficult to study directly.
A lot of studies do say that articaine and prilocaine have a higher likelihood to cause paresthesia.
Pogrel JADA 1995 found no correlation between using lidocaine, prilocaine, and mepivacaine. There was a correlation between dental anesthetic nerve damage and the number of times patient was injected. Although this could result from more chances for physical injury and/or higher doses. A correlation was also found with the patient reporting a feeling of an electric shock, which is a sign the nerve is being injured by needle. Finally, a correlation was found for those that had dental work requiring local anesthetic in that area recently.
Pogrel 2000 found prilocaine more likely to have caused dental anesthetic nerve damage.
Again in 2007 Pogrel found prilocaine to be far more likely to cause nerve damage than articaine or lidocaine.
Garisto 2010 found dental anesthetics with higher concentration were more likely to cause dental anesthetic nerve damage. The main two anesthetics in the study are articaine and prilocaine. Prilocaine was 7x more likely to cause damage and articaine was 3.5x more likely. Others have found similar results, such as Haas 1995 and Gaffen 2009.