Scott R. McAdoo, DDS
In response to Dr. Kevin W. Toal`s response in the July issue of Dental Economics, I apologize for implying that he was unaware of the Olea study (see original letter in the March issue of DE). Dr. Toal notes that Olea was cited three times since 1996 in the Journal of the American Dental Association. I feel Dr. Toal is confusing argument with truth. Just because someone is quoted or cited does not substantiate it as true - although it does seem to erroneously establish it in others` minds as true. I could get five people to agree that the world is flat and then we`d cite each other as "experts" and establish it as fact.
I understand that to test a chemical, you must elutriate it from the compound or, in this case, the composite filling material, and then see what (if any) effect it has on cell lines. That`s a lucid and well-thought-out argument, counselor. Let`s apply a little God-given sense. I often have patients raise concerns about the aluminum in composites and porcelain. I tell them that crystal is a well-bound aluminum salt, much like the aluminum in glass. I go on to point out that landfill operators will tell you that getting rid of glass is their biggest problem. Paper breaks down in years, metals in decades, plastics in centuries, and glass in millions of years. So how much aluminum is a patient truly exposed to? Probably none. Unless you have patients who are swishing with boiling hydrochloric acid, this argument is probably moot.
Dr. Toal points out that this issue stems from the debates of the amalgam/composite series from 1999 issues of DE. I might point out that you do not have to expose amalgam to 100° C in a solution of pH 1 or pH 14 to elutriate mercury. All you have to do is collect the mercury vapor as it is released at room temperature - let alone body temperature - as the ADA finally admitted in 1985. If mercury to be studied can be elutriated in any concentration, and if it can adversely affect a given cell line, then it must be assumed that a given percentage of our patient population could be susceptible to the adverse effects of that mercury (to use Dr. Toal`s exact words, substituting mercury for chemical). And where exactly are the very easy-to-perform studies showing the adverse effects against cells? You won`t see any in JADA because the results will read "killed cells."
I agree with Dr. Toal`s last paragraph that further studies must be done. The dental profession must be aware of any potential hazards in the use of dental composite and amalgam.