Once again, I’ve been suckered into believing something I read on the Internet. This time, a poster on the Ms. Boards, in a thread about tongue piercing, mentioned that friend of hers, who worked in a “very reputable medical school in California” (I was getting suspicious already) said:
“Cancer doctors are starting to see neoplasms associated with tongue piercings. Unlike the belly button, nose, and outer ear, tongues are constantly washed in that rather caustic substance known as saliva. No matter what the metal, some ions will be coming off now and then, and those will be running around your mouth doing things they shouldn’t be doing, like messing with cells that would be doing fine otherwise.”
Neoplasms=cancer, btw. I looked that up afterward. So, true or not? Does it even make any sense? Should I take my tongue piercing out tonight?
See, Monty, this was exactly the kind of logic that I was looking for. Freaking out over your supposedly impending cancer doesn’t really free you up to think, um, sensibly.
What makes me wonder is this. If saliva is acidic enough to cause this to happen, (if jakelopes cite is reliable) why weren’t acidic food and drink included in the warning as well?
We eat and drink things that are more acidic than our own saliva. Orange juice was the first thing that came to my mind. Not to mention Coca-Cola.
Metal objects in the mouth of some people can lead to contact stomatitis inside the mouth can lead to irritated areas that ulcerate and this can generate long term lesions that can lead to neoplasms.
Whether this is due to “caustic” saliva relasing ions is open to question.
Any device in the mouth (including dentures) that causes long-term irritation (as astro was suggesting) can create an environment that predisposes to malignancy.
However:
I haven’t seen or heard of any research, or pronouncements by the CDC (one could do a PubMed search) that this has been shown to occur with piercings in the mouth. The “friend at the reputable medical school” should be able to provide references in the literature.
I suspect it would be a lot easier to find reports of nasty infections from non-sterile piercing equipment.
By the way, a neoplasm is any kind of tumor, benign or malignant. “Tumor” and “neoplasm” don’t necessarily equate to malignancy.
I think tongue-piercing is dis-gusting. But telling people their tongues will turn into cancerous lesions the size of a softball is probably not the right way to convince Our Young People not to do it.
I am not a chemist, but that doesn’t sound right to me. The pH of an aqueous solution is the opposite of the log base ten of the concentration of hydrogen (hydronium) ions in that solution. So anything with a pH must be a solution, ie. contain water as well as an acid or alkali. Pure acids or alkalis therefore have no pH at all, not a pH of 0 or 14.
For instance, pure (anhydrous) nitric acid is an oily liquid. Although extremely acidic, it does not strictly speaking have a pH at all. Sodium hydroxide crystals are extremely alkaline, and they don’t have a pH either.
Also, I can’t off the top of my head think of any reason why a solution should not have a concentration of hydrogen ions greater than 1 mole per litre, or less than 10^-14 mol/l. 2 moles per litre of hydrogen ions could be achieved by dissolving 126 grammes of nitric acid in a litre of water, and would yield a pH of -0.3
AgBack (and other hijackers): negative pHs are definitely possible. “Maximum strength” hydrochloric acid (about 37% HCl dissolved in water) has a pH of approximately -1.1, and industrial grade sulfuric acid is even lower, IIRC. It’s also possible to go well above 14 on the basic side; a fully saturated solution of sodium hydroxide has a pH of about 15.
Interestingly, in checking the fact that PHs can indeed go negative for strong acids (such as HCl and HNO3), I also discovered that PHs can actually go higher than 14 for strong bases (such as NaOH). So it turns out that you were both mostly right (usually PH ranges from 0 to 14, however, it can go less than 0 and greater than 14 for solutions containing strong acids and strong bases respectively.) You were right to say that pure acids do not have a PH per se, as one would have to refer to a “0.5 M solution of HNO3”.
As for the rest of jackelope’s statement, he was correct to say that saliva is not caustic (if indeed it does have a PH of 6.6 to 6.9). Therefore, I doubt the validity of the source that claims there is a correlation between tongue piercings and cancer incidences.
Since I’m sitting around the lab right now, I ran a quick experiment: the pH of my saliva is 6.8, damn close to neutral.
So there.
I’ve had the same tongue ring for, oh, eight or nine years and I haven’t noticed any wear on it, like one would expect if it had been dissolved by acids and/or bases in the mouth. Jewelery from a reputable shop is usually implant-grade surgical steel, meaning it’s the same stuff used in medical implants. Which are not known to cause cancer.
Furthermore, anything and everything you eat contains ions, so I don’t know why this person “at a reputable medical school” is concerned about them.
Eighteen years later, braces these days contain almost no metal at all. Even when they did, braces are commonly only worn for a year or two in adolescence then are removed. Tongue piercings are in the mouth 24/7, usually for years at a time. Very different thing.
I never noticed. I had all of them replaced with crowns at one point in my life because new dentist said that there was too much filling per tooth. I didn’t notice any difference. Well, except that I found that I can’t do laughing gas cause it gave me dizzy spells for months after it was used.
I think they’re confused because they’ve heard that digestion begins in the mouth, with saliva, and they don’t know that digestion does not necessarily include “caustic” materials. Saliva contains enzymes, which are not corrosive and which pretty much leave metals alone.
