Dr JT (Koos) Marais

In defense of amalgam: A case report

Many colleagues take pride in practicing so-called "amalgam free dentistry," claiming the benefits of esthetics and the absence of mercury in resins and porcelain. By denying patients the benefit of a proper and well-designed amalgam restoration, they are actually causing patients harm and unnecessary expense. These expenses, when added together on a national scale, are a very significant cost factor, driving up medical inflation. The claims about the "toxicity" of amalgam are blatantly untrue and devoid of any basis in reality. One could even argue that these claims are deliberately designed to defraud the public.

 The patient, a forty year old female, attended with a main complaint of a tooth in the lower left jaw with a cavity, with no history of pain. Examination confirmed the presence of a cavity on the mesio-occlusal surface of the second lower left molar tooth (37). On the buccal surface two adequately sealing, separate, amalgam restorations were also noted.

 Treatment was discussed with the patient, emphasising the slight risk of post-operative sensitivity. The patient was asked about any preference for a particular restorative material and the patient made it abundantly clear that durability, and not esthetics, was her main concern. This steered the discussion to the use of gold or amalgam. It was noted that gold would in all probability last a life, time but would require significantly more tooth tissue destruction and also involve much greater costs, a seven fold greater cost, to be exact.

 In the end the patient left the decision to me, allowing me the freedom to "do what is best."

 I anaesthetised the mouth and isolated the tooth with rubber dam. I then removed all decay and studied the remaining tooth structure again (Figure 1).

 Figure 1: Note the two clinically acceptable buccal amalgam restorations.

At this stage I reconsidered the use of all restorative materials again. Due to the size and extent of the cavity the use of direct resin was not an option. All that remained was porcelain, indirect resin, gold and amalgam. Porcelain and indirect resin would involve laboratory costs, totaling an amount of R6000-R7500. Gold would cost approximately R8000. In all three cases the two additional buccal amalgam restorations, clinically perfect, would also be removed, also requiring removal of all enamel and dentine coronal to the two amalgam restorations as well as impressions of the difficult sub-gingival margins. The destruction of the dentine and enamel and risk of leakage of the resin dentine/enamel interface would also carry greater risk of post-operative sensitivity, possibly leading to root canal treatment and subsequent crowning of the tooth, with the added cost of say R14000. Also, the use of indirect resin or porcelain requires a perfectly dry working field, something that is not easily accomplished in the area of the second molars, even with the aid of rubber dam.

 The patient had entrusted me with the care of her teeth, allowing me carte blanche, to do exactly as I pleased. All she asked for was to "do what is best." One can abuse this trust and even justify one's choice of treatment on the basis of esthetics (porcelain) or "longevity" (gold), but in the end the decision of "what is best" can and should be judged against the tenets of the 4000 year old Hippocratic oath, embodied in these three words, Primum Non Nocere, First Do No Harm. I subscribe to this oath and these three words form part of my personal logo. The decision was easy: I left the two perfect amalgam restorations in situ and filled the cavity with amalgam (Figure 2).

Figure 2. The cavity was restored with amalgam and the two old amalgam restorations left in place.

Leaving the two old amalgam restorations in situ is no problem when using amalgam for the new cavity, but it will be frowned upon if porcelain or resin or gold had been employed. This restoration would in all probability last a very long time, more than a decade. Esthetics is of zero concern. Amalgam is known to initially leak slightly, but then to undergo corrosion, ultimately creating an almost perfect seal. On the other hand, the bond between resin and dentine/enamel is known to degrade with time, eventually ending in secondary decay or pulpitis or both. The extension of the cavity margins by the removal of the two amalgam restorations would have compounded the risks, especially since these two restorations extend sub-gingivally, a notoriously difficult area to replicate in an expression and to isolate for bonding.

 The use of amalgam in this case was based on sound scientific and ethical principles. It was also, by far the least expensive technique, by a factor of at least seven. It was also the safest technique with the lowest risk of post-operative sensitivity.

 I believe I have satisfied the patient's need of wanting "what is best." By practicing "amalgam free dentistry" one is denying patients a very safe, well proven, cost effective and valuable service.