There are many patients in general practice with health complaints that cannot be medically explained. Some of these patients attribute their problems to dental amalgam.

This study examined the cost-effectiveness of the removal of amalgam fillings in patients with medically unexplained physical symptoms (MUPS) attributed to amalgam compared to usual care, based on a prospective cohort study in Norway.

Costs were determined using a micro-costing approach at the individual level. Health outcomes were documented at baseline and approximately two years later for both the intervention and the usual care using EQ-5D-5L. Quality-adjusted life year (QALY) was used as the main outcome measure. A decision analytical model was developed to estimate the incremental cost-effectiveness of the intervention. Both probabilistic and one-way sensitivity analyses were conducted to assess the impact of uncertainty on costs and effectiveness.

In patients who attributed health complaints to dental amalgam and fulfilled the inclusion and exclusion criteria, amalgam removal was associated with a modest increase in costs at the societal level as well as improved health outcomes. In the base-case analysis, the mean incremental cost per patient in the amalgam group was NOK 19 416 compared to the MUPS group, while the mean incremental QALY was 0.119 with a time horizon of two years. Thus, the incremental costs per QALY of the intervention were NOK 162 680, which is usually considered to be cost-effective in Norway. The estimated incremental cost per QALY decreased with increasing time horizons, and amalgam removal was found to be cost-saving over both 5 and 10 years.

The authors concluded that this study provides insight into the costs and health outcomes associated with the removal of amalgam restorations in patients who attribute health complaints to dental amalgam fillings, which are appropriate instruments to inform health care priorities.

The group sizes were 32 and 28 respectively. This study was thus almost laughably small and therefore cannot lead to firm conclusions of any type. In this contest, a recent systematic review might be relevant; it concluded as follows:

On the basis of the available RCTs, amalgam restorations, if compared with resin-based fillings, do not show an increased risk for systemic diseases. There is still insufficient evidence to exclude or demonstrate any direct influence on general health. The removal of old amalgam restorations and their substitution with more modern adhesive restorations should be performed only when clinically necessary and not just for material concerns. In order to better evaluate the safety of dental amalgam compared to other more modern restorative materials, further RCTs that consider important parameters such as long and uniform follow up periods, number of restorations per patient, and sample populations representative of chronic or degenerative diseases are needed.

Similarly, a review of the evidence might be informative:

Since more than 100 years amalgam is successfully used for the functional restoration of decayed teeth. During the early 1990s the use of amalgam has been discredited by a not very objective discussion about small amounts of quicksilver that can evaporate from the material. Recent studies and reviews, however, found little to no correlation between systemic or local diseases and amalgam restorations in man. Allergic reactions are extremely rare. Most quicksilver evaporates during placement and removal of amalgam restorations. Hence it is not recommended to make extensive rehabilitations with amalgam in pregnant or nursing women. To date, there is no dental material, which can fully substitute amalgam as a restorative material. According to present scientific evidence the use of amalgam is not a health hazard.

Furthermore, there is evidence that the removal of amalgam fillings is not such a good idea. One study, for instance, showed that the mercury released by the physical action of the drill, the replacement material and especially the final destination of the amalgam waste can increase contamination levels that can be a risk for human and environment health.

As dental amalgam removal does not seem risk-free, it is perhaps unwise to remove these fillings at all. Patients who are convinced that their amalgam fillings make them ill might simply benefit from assurance. After all, we also do not re-lay electric cables because some people feel they are the cause of their ill-health.

29 Responses to Is removal of dental amalgam a good idea?

  • Two points that arent really addressed by this summary of the study:
    1) Was there testing done on the patients to see if they had Mercury toxicity. I like the way they use the term Quicksilver which sounds so pleasant compared to Mercury, one of the most toxic substances on the planet.
    2) Was the Mercury removal done according to the recommended protocols for the procedure.
    Certainly there are going to be patients who mistakenly attribute their health problems to their mercury which might not be warranted. They should have been taken out of the study.
    If the mercury removal is done without proper safeguards it can actually worsen their health so that even 2 years later they could be suffering from the mercury that migrated elsewhere in the body.
    This study seems designed to obscure the benefits of Mercury removal.

    • The article quoted that mentions quicksilver is a translation from a German language article. The German word for mercury is queckselber.

      The protocol for mercury removal seems to be that of a dental practitioner. Has it been evaluated?

    • “I like the way they use the term Quicksilver which sounds so pleasant compared to Mercury, one of the most toxic substances on the planet.”

      Good grief!

      1. “Mercuryis a planet.
      2. “mercury” is a chemical element that is commonly known as “quicksilver”, not “Quicksilver”.
      3. mercury is not “one of the most toxic substances”; botulinum toxin is orders of magnitude more toxic, having an LD50 of 1 ng/kg.

      • Gosh! Really tough comments. I dont know if I can recover from that.

      • “Organic and inorganic mercury compounds have different effects and hence LD50 values (which are typically between 1mg/kg and 100 mg/kg).”

        Pretty damn toxic for something that is placed inside peoples’ mouths permanently, on a regular basis. I dont think there is a dental protocol for botulinum toxin, although stupid vain people do use it intermittently for beauty treatments. And mercury is not easily cleared from some systems of the body so it accumulates. It seems that the BT toxin gradually loses its activity. Not the case with mercury.

        • Elemental mercury is not particularly toxic. It is dangerous in the form of mercury vapour which is emitted by amalgams in barely-perceptible amounts which have not been demonstrated to be harmful. It is also dangerous as methylmercury which becomes concentrated in the flesh of oily fish following environmental contamination with elemental mercury.

          And before you debate further Stan, please bear in mind that I’m a dentist and hence do know what I’m talking about here.

          • as that would have ever stopped Stan!

          • Lenny: It is dangerous in the form of mercury vapour which is emitted by amalgams in barely-perceptible amounts which have not been demonstrated to be harmful.

            I haven’t looked into the research but one has to consider, amongst other things, emitted dose over time. What is the longest study done on this topic?

          • I haven’t looked into the research but one has to BS a little anyway

          • This one is based upon findings upon death.

            “ I-Hg in both blood and occipital cortex, as well as total-Hg in pituitary and thyroid were strongly associated with the number of dental amalgam surfaces at the time of death.”


          • Lenny,

            ‘Stan’, ‘stan’, and ‘DC’ provide yet more illustrations of the contrast between genuinely knowledgeable persons and numpties, quacks, and woomeisters.

          • Interesting how Pete is allowed to continuously violate rules 2-5. But I suppose it’s not surprising a double standard seems to exist here.

          • Interesting how Pete is allowed to continuously violate rules 2-5. But I suppose it’s not surprising a double standard seems to exist here.

            Are you saying you would like to have comments posted which violate those rules, or that Pete Attkins shouldn’t be allowed to?
            If the first, what’s the benefit or point of making comments that violate those rules?

          • The quantity of emitted vapour depends on design of the drill, the rotational speed, quality of cooling and the effektivity of suction. Greetings from Bremen!
            My article via dzw:

          • Robin, I am pointing out that Pete regularly violates the rules that Ernst has set up. Referring to folks as “numpties, quacks, and woomeisters” adds nothing to the conversation and he didn’t even address the topic at hand. But perhaps that is all he has to offer.

          • QUOTE

            ad hominem

            It isn’t actually an ad hom argument unless you’re using the assertion that he’s a fecking eejit as the basis for your assertion that he’s wrong. Here you have clearly based your conclusion that he’s a fecking eejit on the evidence that he himself has posted.

            Ad hom: “You’re wrong because you’re a fecking eejit.”
Not ad hom: “You’re wrong and you’re a fecking eejit.”

            Also not ad hom: “You’re a fecking eejit because you’re wrong.”


            END of QUOTE

          • Interesting, from 2012.

            “The half-life of mercury in the brain is not entirely clear, but is estimated to be as long as approximately 20 years. Elemental mercury is bound strongly to selenium or SH-groups after oxidation in the brain, which may contribute to remaining brain deposits for a long time [21].

            The adverse health effects due to additional mercury exposure from dental amalgam remains a subject of debate among researchers.”


          • DC wrote

            I am pointing out that Pete regularly violates the rules that Ernst has set up. Referring to folks as “numpties, quacks, and woomeisters” adds nothing to the conversation

            There are lots of comments from a lot of different people on this site that are just interpersonal fencing and don’t have any logical substance. Such comments discourage good discussions, too. It’s the online equivalent of farting loudly in a crowded room – the person quickly gets space around them.
            It could be a lot better – we have such a knowledgeable and productive blogger.

          • Robin: it’s more the issue that there are set rules here. Does Ernst pick and choose when and who has to abide by them? It appears so.

          • do you pick and chose what you consider evidence?
            of course not – you are super human!

          • “Referring to folks as ‘numpties, quacks, and woomeisters’ adds nothing to the conversation.”

            By the same token, referring to folks as “knowledgeable and productive” adds nothing to the conversation.

            “It is a pity the unintelligent aren’t aware of their lack of intelligence.”
            — Frank Collins

  • It also doesn’t indicate whether they controlled for health problems caused by mucoid plaques. 😉

  • Measuring mercury levels pre and post removal would have been a good idea. The fact they didn’t lessens the ability of this study to provide reliable evidence as to the health impacts of amalgam fillings.

    We should also consider the fact that here we have a group of people who are convinced that amalgam fillings are a problem. They have them removed. They report feeling better. Hardly surprising.

  • Hal Huggins was the manufacturer of the amalgam “controversy”. An egregious and amoral quack, he had his dental license removed in 1996. One of his marks was the breathtakingly stupid late and entirely unlamented Sandra “Brown Bag Pantry” Herrmann-Courtney who would often spout ill-informed tripe on this blog.

    The Quackwatch pages on Huggins and his modus operandi are highly informative.

  • Amalgam fillings eventually have to be replaced in any case – they don’t last forever.
    I had to get an amalgam filling replaced recently, and actually had some problems getting it replaced with amalgam. It seems that amalgam fillings are being used a lot less, because of people’s fears about them and because fairly good alternatives are available.

  • My dentist only recommends replacing amalgam fillings if they are somehow not doing their job properly (e.g. cracked).

    When she replaces them, she uses a non-amalgam filling.

    I was under the impression that the main mercury vapour risk from amalgam fillings was to the dental technician who prepares them, but that may well be incorrect.

    • Technicians aren’t involved in the preparation of amalgam. The liquid mercury and powdered alloy are predosed in capsules which are mixed in a machine called an amalgamator. Previously, alloy and mercury were loaded into an amalgamator which would dispense and mix fixed amouts (so-called “spills”) but these machines are no longer used. Prior to that, the alloy and mercury was put into a small mortar called a Dappens pot and hand-mixed using a pestle but that was a long, long time ago. In my 30+ year career, most of the amalgam I’ve used has been encapsulated. I also stopped routinely placing amalgams twenty years ago.

    • Thanks, Lenny. I’m pretty sure I remember amalgams being prepared by the technician when I was young, but that was a good bit longer than 30 years ago.

      I’m not surprised that that’s no longer the case.

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