Dental Tribune USA

Reflecting on oral-health’s good old iodine days

By Patricia Walsh, RDH, USA
March 19, 2015

While anxiously waiting for the “Downton Abbey” television series to start up again, I got my English history fix by reading the history of Wentworth Castle. The book covered the trials and tribulations of an aristocratic family in a home three times the size of Buckingham Palace. 

I was taken by surprise when the author mentioned the cause of death of a high-ranking nobleman as “quinsy throat.” In modern times, with the arrival of antibiotics, you wouldn’t hear of this — at least not in a developed nation. The more I thought about it, I don’t think I had heard the term “quinsy sore throat”for a very long time. Around here, if your throat is starting to close off, you’ve probably gotten yourself to an emergency room “pronto.” It is an abscess in the peritonsillar area that often needs drainage.

While tonsillitis is more common in children, both kids and adults are susceptible to quinsy. One can only assume that if the breathing restrictions don’t kill you, the resulting septicemia might later. A quinsy sore throat can infect both the blood supply and individual organs.

I can recall having my tonsils painted with iodine by the school nurse when I was starting to “come down with something.” A tall canister of extra long cotton swabs were one of the staples of her office.

I can’t say whether there’s any scientific proof that tonsil painting reduced cases of severe tonsillitis. But I do know that some homeopathic remedies call for gargling with a watered down Betadine solution even today. I’ve also heard that eating three or four marshmallows helps to soothe a sore throat. Apparently it has something to do with the gelatin. I suppose if you’re not eating at all, any caloric intake will do, so it might as well be fun!

Washington’s epiglottitis
George Washington’s physician mentions his quinsy sore throat prior to his death at age 63. He was thought to have suffered from a quinsy sore throat that quickly turned into epiglottitis — most likely his cause of death. The swelling of his epiglottis cut off his air supply. He also suffered from malaria, TB and smallpox during his lifetime. How sad that it may have been a very bad sore throat that got him in the end. The blood-letting technique that was used at the time probably hindered his recovery as well.

When I was a dental hygiene student, we were occasionally brought to a local city clinic to do checkups on grammar school children. These children were the poorest of the poor and were seen on old WWII wooden field chairs. There was no money in the budget for fancy things like “disclosing tablets.” Instead, we used iodine on long cotton swabs to paint the teeth and disclose the plaque. Our instructor kept the large bottle of iodine. The iodine that a physician uses is water-based as opposed to the alcohol-based type available for home use. We used eye droppers to fill up our little green-glass dappen dishes for each patient. I would think the taste alone would put children off dentistry for some time to come. We rinsed their mouths with a rubber ball syringe, and they expectorated into a kidney basin. Considering the number of patients I currently see with known iodine allergies, it’s amazing we never heard of any children having a reaction. Then again, people are now more “allergy aware” then they once were. There is probably an equal number of children with red-dye allergies who would have done no better with the modern disclosing tablets.

In spite of iodine’s unpleasant taste, I have been known to recommend subgingival irrigation with a Betadine solution (brand name for povidone-iodine). The key to this is the dosage. I tell the patient that if the water turns brown, they’ve added too much. There is a huge temptation to use too much because most drug stores sell only very large bottles. But between the bad taste and the potential for staining, it’s easy to see why less is more. Iodine kills the gram negative bacteria that live in the darker recesses of a deep perio pocket.

There is another clinical application for iodine in dentistry. An iodine staining test used to assist in discerning attached gingiva as mentioned in “Periodontics Revisited” by Shalu Bathla, MD. The clinician can: “paint the gingiva and oral mucosa with Lugols solution (iodine,water and potassium iodide). The aveolar mucosa takes on a brown color owing to its glycogen content while the glycogen-free attached gingiva remains unstained. Measure the total width at the unstained gingiva and subtract the sulcus/pocket depth from it to determine the width of the attached gingiva.”

In the Chernobyl disaster, some Lugols solution was used as an emergency source of iodide to block radiation iodine uptake, simply because it was widely available as a drinking water decontaminant, and pure potassium iodide without iodine (the preferred agent) was not available.

Mama don’t take my Mecurochrome away
Mecurochrome and merthiolate were also very popular in my childhood. We proudly wore our hot pink tinctures over scraped knees like playground battle scars. When it was determined that mercury was detrimental to one’s overall health, Mecurochrome was banned from general use. The U.S. Food and Drug Administration put very strict limitations on the sale of Mercurochrome in 1998 and stated that it was no longer considered to be a GRAS (generally recognized as safe) over-the-counter product. Merthiolate was another commonly found antiseptic and antifungal agent that was banned because of its mercury content.

Iodine was determined by the U.S. Justice Department to have a roll in the production of methamphetamine and is now a restricted purchase. I wouldn’t recommend bringing back anything more than 4 fl. oz. of tincture of iodine from your next Mexican vacation. Scrape your feet on a coral reef, and you might find yourself detained at customs for questioning about your toiletry kit.

While iodine crystals are the form of choice for illegal drug labs, some smaller manufacturers are known to combine tincture of iodine with hydrogen peroxide. Some businesses have removed iodine from the shelves, while others are simply restricting large quantity sales — i.e., more than $100 worth. When I asked my local pharmacist about Walgreen’s policy, he pointed to the surveillance cameras above the tincture of iodine shelf. Legitimate medical laboratories that do gram staining now have additional paperwork due to the restrictions on iodine strengths and quantities.

Iodine getting harder to find
The old-time iodine bottle with the skull and crossbones sitting in the medicine cabinet has come and gone. In this new age of communication and entertainment, I wonder if a child would even be put off by the sight of a poison label. Children are exposed to cartoon pirates at such an early age. In the mid 19th century, cobalt blue bottles or raised glass lettering were used to help in the identification of poison.

While there is no federal mandate for small quantities, iodine has disappeared from a few pharmacies and department store shelves the way Sudafed did most recently. Home brewers take heart, these pharmacists just require that you sign a poison-control statement and list the reason for your purchase. For those of you who still buy your beer in the traditional manner, iodine is often used as a test for starch conversion in the mash.


This article was published in Hygiene Tribune U.S. Edition, Vol. 8 No. 2, February 2015 issue.


  • Abelha says:

    Is iodine (mouth rinses) selective of gram negative bacteria? Does it affect gram positive? If so, does iodine mouth washes interfere with nitric oxide production?

  • E M Dutton says:

    I had trench mouth as a kid in the 1950’s. My dr treated it with some mix of iodine and it stained my teeth. I wonder if the iodine or the trench mouth could be the reason I have had cervical dystonia, spasmodic dystopia with voice tremor ever since then.

  • Kelly says:

    Not sure where you’re living, but iodine is available all over the web, many forms and bottle sizes.

  • mel says:

    E M Dutton, it would most certainly have not been the iodine.

  • Tony L says:

    I always imagined iodine would kill all cavities forming bacteria in the mouth since dentists use it for oral surgery, and surgical wards for regular surgeries etc. Also, kill pathogens in contaminated water, so how come it would not help us keep our mouths free from caries , gengivite the the like.

  • Regina Kray says:

    I have an infected tooth its had an abscess. Its had a root canal its attached to a bridge. I put iodine around the infection with cotton swabs it hurts but it seems to be working. I think its been giving me a slight sore throat so l dabbed a tiny bit on my sore throat thin rinsed it off. It cleared that up to. Everyday though it comes back flood particles get in the tooth then my throat gets a little sore. So l repeat the process. I have appointment December 10th they want 180 dollars which l did not have. So this is my interim treatment

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