I'm about to have major dental surgery. Are there any dangers from dental anaesthetic? G T, Windsor........
The products now used by most dentists (lidocaine, prilocaine, procaine) are all compounds containing aniline, an aromatic hydrocarbon used to manufacture rubber and varnishes, photographic chemicals and other pharmaceuticals. Other members of this family include benzene, phenols, hydroquinone and naphthalene. These substances, also used in household products and pesticides, are known to accumulate and damage the bone marrow, causing depressed immune function (Townsend Letter, April 1998).
American researcher Dr Alfred Nickel, who has studied these substances in depth, says that aniline compounds are "well documented" human poisons, classic carcinogens and neurotoxins. Although bladder cancer developing among aniline dye workers was described in the medical literature as long ago as 1895 by a German doctor, the use of novacaine, which was developed in 1905, soon became widespread.
The dental profession has always maintained that once aniline is incorporated into a local anaesthesia, it is rendered benign, and that the anaesthetic molecules are excreted by the body.
According to Nickel, this assumption was based on pharmaceutical companies' assurances, which in turn were derived from a single study showing that 10 per cent of injected local anaesthetic was recoverable from urine. Exactly where the other 90 per cent of the anaesthetic landed up was never actually explored (BG Covine, HG Vassallo, Local Anesthetics: Mechanisms of Action and Clinical Use, Grune & Stratton: 1976).
Injecting aniline as an anaesthetic is undoubtedly the most efficient way of infiltrating the body with this poison because it enters the bloodstream, bypassing the gastrointestinal barriers and the liver.
According to Nickel, exposure to aniline in dental anaesthetic far exceeds the maximum daily occupational exposure recommended by the Occupational Safety and Health Agency (OSHA) and the International Agency for Research on Cancer. These agencies suggest 10 mg per cubic meter of analine for long term exposure and 20 mg per cubic meter for short term exposure. According to Nickel, just 1 cc of 2 per cent lidocaine (the usual strength in dental anesthetic) will produce 10 mg of 2,6 dimethylaniline. A dentist might inject 14 cc of 2 per cent lidocaine while extracting wisdom teeth and 5-8 cc of lidocaine if he is doing caps or fillings. This can go on for as long as six months for a full mouth reconstruction. This means that a patient gets a whopping 140 mg of 2,6 dimethylaniline every time he gets a tooth out, or 50-80 mg of the stuff for other routine work.
Compared with tobacco, which also contains aniline, a single cigarette contains 102 nanograms of 2,6 dimethylaniline. According to Dr Nickel, you would have to smoke 20 unfiltered cigarettes every day for 12.9 years to inhale the same amount of 2,6 dimethylaniline that you get in a single cc of 2 per cent lidocaine.
According to researcher, Susan Stockton, writing in the Townsend letter (June 1998), the side effects of lidocaine include excitement, hallucinations, distorted perceptions, changes in heart rate and dyspnea (laboured breathing). Excessive doses may even cause methemoglobinemia (an inability of the body to utilise oxygen properly).
For 25 years, we've had laboratory evidence contrary to the prevailing view showing that local anesthetic can convert into toxic metabolites in human tissues before it gets to the organs of metabolic excretion (the liver, for instance) (J Pharmol Exp Tehra, 1972; 180: 454-463). Nevertheless, according to Nickel, "the implications of this study are still widely ignored."
Dr Nickel himself conducted a case control study of nearly 5000 patients who'd received oral surgery and discovered that paresthesia, or pins and needles a well known complication of oral surgery in between 1 and 5 per cent of cases was actually a toxic side effect of local anaesthetic (Anesth Prog, 1990; 37: 42-5). The real significance of Nickel's study is that it again shows that dental anaesthetic does convert to aniline in the body.
The Anesthetic and Life Support Drugs Advisory Committee, an arm of the FDA, have given a nod to this by ruling that the following warning should appear on EMLA, a skin cream which contains lidocaine and prilocaine: "Metabolites of both lidocaine and prilocaine have been shown to be carcinogenic in animals."
Yet that warning has not been extended so that patients are ever told about the risk of dental anaesthetic.
Some of the most compelling human work by Dr Nickel concerns a review by his research team of 30 cancer patients at a local hospital. All the patients had total body scans, which also revealed their full dental history. These scans demonstrated that each patient had undergone between 12 and 28 crown and bridge dental procedures, which would have meant extensive exposure to local anesthetics.
Even if you don't develop cancer, many side effects of aniline poisoning (that is, ingesting more than one gram) include headache, paresthesia, poly neuritis, dizziness, convulsions, muscle weakness, hypotension and irregular heartbeat. One study says that a form of aniline can induce allergies. If you are concerned, ask your dentist to follow the lead of many holistic dentists in America, who have switched from using aniline based anaesthetics to intravenous Demerol.