Does Dental Infection Interfere With Injected Anesthesia?

[ClaryS]

I had a horrible experience at the dentist yesterday and left shaking, totally upset. I had been the following week and told a large molar was beyond repair and needed an extraction. I was given a 7 day course of Amoxicillin ( 3 x 250mg) and went back yesterday for the extraction. After the initial local anaesthetic the dentist started rocking the tooth and soon I was in agony -I have a strong pain threshold and have had extractions before so am aware there is normally little if no pain. After 2 more injections and something applied directly to the tooth the pain was no better, in fact worse, a burning sensation like someone was sticking a hot knife into the tooth. She(the dentist) stopped and said she would not lie and that she could go ahead and try some more to extract the tooth but I would be in agony because there was still some infection at the root and this stopped the anaesthetic from working. I opted to leave it and take another course of stronger antibiotic ( Metronidazole 400mg) and go back in 3 days for her to try again. Is this true? Why would an infection inhibit the anaesthetic? when I got home I was in such a state I phoned the surgery and asked to be referred to a different dentist or a dental hospital and they were very good and have booked me into a specialist dental hospital on Saturday. now I'm petrified -20 years of successfully fighting a fear of dentists gone down the pan in 20 minutes and I can't eat or sleep for the worry of what will happen on Saturday. So, was the dentist correct in what she said or was it perhaps an excuse for bad dentistry?

[Sqad]

J2PUR is the resident Aber dentist and he will surely be along.

Yes, infection MAY affect the effectiveness of a local dental anaesthetic, but usually,not always, a second "top up" of local usually does the trick.

Also, unless absolutely necessary it is bad dental or indeed surgical practice to introduce a needle into an infected area in case of spread (septicaemia)

In your case and feeling the way that you do , i would ask for intravenous sedation.

[ClaryS]

Sqad, Thanks for the speedy reply. I have been referred to a private practice that specialises in 'conscious sedation' although effect pain management would suffice. I understand that a 'raging local infection' can change the Ph. of the surrounding tissue making the anaesthetic less effective, but as far as I'm aware I have no raging local infection as I've had no pain with the tooth and was given amoxicillin as a precursory to the extraction 'just to be sure'. I asked the question in the hope that the experience was down to bad dentistry from an obviously newly qualified dentist (sorry but she looked about 18) and that the next dentist will know what they are doing.

[Sqad]

LOL...good luck.

[ClaryS]

Thanks squad -I think a bottle of spiced rum would have been a more effective analgesic lol!

[woofgang]

My dentist says yes, also so does this website
http://www.dentalfearcentral.org/fears/not-numb/

briefly the infection changes the Ph of the tissue around the tooth and makes it harder for the anaesthetic to diffuse. Putting in more anaesthetic to overcome this is possible but can be very painful.
From experience, you might not know that you have an infection. I had one which I (and the dentist) was unaware of until he removed the tooth. He always uses loads and numbs well away from the tooth for me as I am such a wimp and the tooth was very loose so it wasn't painful but the smell and taste when the tooth came out were horrendous (anyone having elevenses??)

[Milvus]

I had the same experience last year. The molar was still sensitive after quite a lot of anaesthetic because of an infection. I decided to let him get on with it. It probably wasn't as painful as yours because he was able to loosen the tooth and the actual extraction was very quick

[McMouse]

I have a very low paid threshold and over the years have trained (encouraged) my dentist to inject as much local as possible. I never experience pain.