Published in InterAction 79, Spring 2012
We regret that our medical adviser cannot respond to individual enquiries.
I am having problems with my teeth and getting very anxious about how I am going to have any dental treatment. I have severe M.E. and I am not well enough. I have just been told that there is a problem with the usual local anaesthetics and that if you have M.E. you should have an adrenalin-free one instead.
My dentist has advised me to have my wisdom tooth taken out under general anaesthetic as I had a lot of problems last time I had back teeth removed. But my GP then told me he doesn’t advise me to have a general because it can cause problems with the M.E.
I also need a filling and am worried because I have heard that they contain mercury that can exacerbate M.E. How should I proceed?
Dr Alastair Miller replies:
This poses several questions about dental treatment and M.E. which can be summarised as:
- Are local anaesthetics safe for those with M.E. and if they are not, are those free of adrenaline safer?
- Are general anaesthetics safe for those with M.E. (especially in the context of general anaesthesia for dental procedures)?
- Is dental amalgam a risk to those with M.E.? Is fluoride also a risk or is it safer than amalgam?
We do not have a full explanation or an anatomical (structural), physiological or biochemical basis for how the symptom complex that we recognize as M.E. is generated. It is therefore difficult to predict whether, why or how any of the interventions described above (local or general anaesthesia and dental fillings with amalgam) could or should adversely affect the person suffering from M.E.
There are no scientifically controlled trials demonstrating that any of these interventions has any effect on M.E. but of course there are numerous patient experiences to that effect.
The first thing to establish is whether any particular dental procedure is essential and this involves an open dialogue with your dentist to discuss the risks and benefits of dental surgery. If any procedure is essentially a cosmetic one then only you can make the decision as to whether any risk (however small) of an adverse effect on your M.E. is justified.
If, however, the proposed surgery is to reduce the risks of more extensive surgery in the future, to reduce or eliminate chronic low- grade infection or to control unpleasant symptoms, then you should probably accept the small risk that it may adversely affect your M.E.
Local anaesthetics are often given in conjunction with adrenaline. This is a natural body substance produced by the adrenal gland. When given with the local anaesthetic it causes constriction of blood vessels in the local area and therefore reduces blood loss during subsequent surgery.
There have been suggestions that some symptoms of M.E. may be caused by excess adrenaline and I assume that this forms the basis for the advice from some quarters to avoid adrenaline containing local anaesthetics. This is something that you need to discuss with your dentist.
If adrenaline-free local anaesthetic is readily available and your dentist does not feel that it will compromise surgical safety, then it seems reasonable to request this. However, there is no convincing scientific evidence that adrenaline will have an adverse effect.
In general terms, irrespective of whether you have M.E., it is always safer to have local anaesthesia rather than a general anaesthetic. No general anaesthetic can ever be regarded as 100% safe and there is no evidence that general anaesthetic is less likely to cause problems in those with M.E. than local anaesthetics. Unless there are compelling dental reasons then you should always go for local anaesthetics.
Dental amalgam is made by mixing liquid mercury (about 50%) with an alloy of silver (about 30% silver) with a small amount of tin and copper. This is mixed directly before inserting into a tooth cavity to produce a filling.
The initial putty-like consistency of the amalgam hardens into a robust, resilient substance that lasts for many years. It is strong, relatively low cost and therefore a popular choice for dental fillings (especially in the back teeth where cosmetic considerations are less important). Its use developed in the 19th century and even in those days, there was considerable controversy over its potential adverse health effects.
Concerns are based on the fact that small amounts of liquid or vaporised mercury may be released from fillings over a period of time, and may be ingested or inhaled. It is well known that mercury is a toxic heavy metal and significant exposure can lead to a variety of symptoms including irritability, memory loss and tremors.
It is possible that some of the clinical features of mercury toxicity can overlap with M.E. but there is no clinical epidemiological evidence that mercury poisoning is linked to M.E.
Overall, amalgam use is declining and the main reason for this is that with better dental health (in part attributable to water fluoridation) there is less requirement for cavity fillings. Alternative materials for fillings are also improving and becoming less costly.
However, amalgam remains the most widely used filling material in the UK and US, although its use is restricted in Scandinavia.
Two large scale clinical trials looked at the health effects of amalgam in children and followed them up for five to seven years. They did not show any adverse health events and specifically, there was no evidence of problems with intellect, memory, co-ordination, nerve conduction or kidney function. The current view of US regulatory authority, the Food and Drug Administration, is that there is “insufficient evidence of a link between dental mercury and health problems, except in rare instances of allergic reaction.”
Although there have been anecdotal reports of improvements in health with removal of dental amalgam in those suffering with M.E., there is no conclusive evidence for this and in someone with a large number of fillings (for whom presumably the indication would be strongest) this procedure is likely to be uncomfortable, time-consuming and expensive. I would certainly not advocate it.
If you need an additional filling and you have M.E. then you may wish to discuss alternative approaches with your dentist but having a single or even several amalgam fillings is most unlikely to have an adverse effect in your health. There is similarly no evidence whatsoever that fluoridation of water supplies has any effect in causing or worsening M.E.
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