Pernicious Anaemia Society
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Dental Work, Anaesthetic & low B12 & Folate


I'm posting on the back of something pvanderaa said in an earlier post re. my B12d possibly being caused by Stress, Anaesthetic, Dental work etc.

It reminded me that this week I have 3 dentist appointments!!! One is to see a hygienist (just routine), the other two appointments are for fillings where I will be given a local anaesthetic on both occasions I'm sure.

I probably wouldn't have mentioned my B12d to the dentist not thinking it was relevant so is there something I should know about this? Is it worth calling my dentist to explain and check?

I'm worried that given my GP is not treating me for B12d or Folate deficiency (160 & 2.9) that if anaesthetics/dental work have an affect in reducing B12 further then it may decrease my levels even further???

Any help or advice greatly appreciated. My appointments are Wednesday and Thursday morning.

6 Replies

Local anaesthetic won't affect B12. It's only nitrous oxide (gas and air) that can remove B12 from the blood.


Hi iStevie. The anaesthetic you need to be concerned about in relation to B12 is nitrous oxide (sometimes called laughing gas). This deactivated B12 and people with B12 deficiency are advised not to have it. If having a general anaesthetic, this is not a problem, since there are other drugs that can be used.

There is not an issue with local anaesthetic (the one that dentists inject) and B12 deficiency (unless, of course, you have other things going on that would make local anaesthesia an issue).

But do tell your dentist about your deficiencies - should be part of the routine health screening that dentists do before treating patients. Some people with B12 deficiency experience increased bruising / bleeding (or indeed, increased clotting) so your GP will need to know a out your deficiencies - but telling him/her at the appointment should be sufficient.

Three dentist appointments in a week - yuk 😖

Good luck 👍

P.s. Just going to reply to your earlier question in previous post / thread.


My dentist is well -aware about PA . He knows about glossitis ( swollen red tongue- which is one of the many symptoms ) He also knows about nitrous oxide( laughing gas ) which can affect utilisation of B12. Ask your dentist if he is aware . Local anaesthetic will not affect B12 .A good hygienist will also have this information .

I am shocked that with your low B12 and folate values you are not receiving treatment . Also you need to be tested for Intrinsic Factor Antibodies . Not a reliable test , only about 50 % accurate , but it should be done . Look in the "pinned posts" top right , and print out and take to your appointment .

Best wishes to you .


Amalgam fillings with mercury are also thought to be a cause for depleting B12. As I understand it, B12 is used up to clean up toxic metals from the body.

Some people with a B12 deficiency have had all their amalgam fillings replaced but this can get expensive.

I still have all my amalgam fillings.

If you can avoid having amalgam fillings in the first place that is preferred.

That said, my dentist, when I discussed amalgam with him, thought me a complete nutter and went ahead and filled in a root canal with amalgam. As I was getting a crown on that tooth I didn't push the issue. I get infections in my mouth starting near that tooth and my tongue patches always start up on that side.

I don't go to that dentist any more either.

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Hi thanks for the info. The dentist always starts by asking for update on medical history so I'll be sure to tell them. I'll let you know what they say about it just out of curiosity. :)

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Would definitely tell dentist about B12 absorption problems - in the past dentists used to identify B12 deficiency from glossitis.

As fbirder says there shouldn't be any interaction from the local anaesthetics that dentists use these days - although nitrous oxide was used in the past these days it isn't recommended for use by dentists

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