Expert: Lawrence Spindel DDS, www.lspindeldds.com - 10/15/2008

Question
I was wondfering what is in the needle the dentist uses to kill pain before working on the teeth.  Is there any danger assosciated with this type of chemical.  I will be having work done on my lower tooth this week.  It cracked last week and had to have it temporarily capped for now.  The dentist took a long time injecting the pain killer and I got a little paranoid about the injection.  I have to go through it again this week as he is going to put a more secure filling in the tooth.  Your thoughts are much appreciated.  Nervouse in Hawaii.

Answer
Dear Raul,

Different dentist use several different anaesthetics.  Sometimes dentists use anaesthetic with a vasoconstrictor, and sometimes they use it without.

I personally use 2% lidocaine with 1:100,000 epinephrine or 3% carbocaine (without vasoconstrictor).

The vasoconstrictor is used to make the blood vessels at the injection site constrict so that the anaesthetic will remain at the site of the injection and not travel away in the blood stream.  Anaesthetic with vasoconstrictors last longer and can give more profound anaesthesia.

Dentists will often use anaesthetic without vasoconstrictor if they believe that the patient has a  medical conditions involving their heart that may make them more likely to have a complication following an injection,. Also dentist often do not use vasoconstrictors for some elderly who are frail ,or for patients who have experienced prior complications to an injection.

The most frequent complication of the injection is a racing heart beat. It happens rarely with the injection without the vasoconstrictor.  Much less frequently patients can experience syncope(fainting).

Complications occur less frequently when the injection is delivered slowly so that is why your injection was given slowly. A slow injection is considered good injection technique.

It sounds like your dentist is a careful dentist and has a good injection technique and if you do not have a prior history of any problems after injections , you will most likely be fine!

I hope I have answered your questions and please feel free to contact me again with any future questions.