The reluctant dentist
As a child in Fort Wayne, Indiana, Muhler’s imagination was captured by chemistry. He took as many high school science courses as he could and dreamed of a future surrounded by test tubes and chemical reactions. Then World War II began, and the U.S. Navy had other plans for Muhler. He was almost finished with his undergraduate degree at IU when his draft notice arrived in 1944.
During both world wars, some men were rejected from military service because they couldn’t meet the minimum requirement of having six upper teeth matched by six in their lower jaw. The dental plague was so dire — tens of thousands were turned away over too few teeth — that the U.S. armed forces began seeking solutions. In 1912, on the eve of U.S. involvement in World War I, the U.S. Navy Dental Corps was launched with the intent to train front-line fighters in the war on tooth decay. Three decades later, this dental battle was still underway, and the Navy wanted Muhler to join the fight against cavities by offering him support to attend dental school.
He arrived at the Indiana School of Dentistry in Indianapolis in 1944, feeling ho-hum about a monotonous career filling cavities and pulling molars. “At the time I hadn’t the slightest interest in dentistry,” Muhler recalled.
Enter Harry Day, a chemistry professor at IU Bloomington, who was tasked with teaching biochemistry to first-year dental students like Muhler.
To capture their attention, Day later wrote, he emphasized topics related to dentistry. “The work on tooth decay and fluoride in the diet was a natural.”
For Muhler, the implication of chemistry impacting tooth decay was a game changer. Studying dentistry went immediately from dull to exhilarating. Fluoride and enamel were a match made in chemistry heaven.
At Bloomington, Day and Muhler gathered an assortment of chemicals and lab equipment for the biochemistry course. “Our stockroom was especially well supplied with various fluorides [as] a result of the work of another departmental chemist, F. [Frank] C. Mathers, who had hit upon a method of extracting the element while working for the U.S. Chemical Warfare Service in World War I,” Day wrote.
The pure form of fluorine, F2, is almost nonexistent in nature. Instead the element is typically found in the form of compounds with other elements or molecular groups. When combined with metals — such as tin or sodium — fluorine atoms take on a negative charge, while the metal atoms become positively charged. These negatively charged fluorine ions are referred to as fluorides.
Serendipity was central to the discovery that fluorides are effective against tooth decay.
The story goes back before Muhler was born. It was the early 1900s, and in the hills of Colorado, a bunch of kids in a young dentist’s office were fortunate enough to have almost no tooth decay. Dr. Frederick McKay noted his patients also had brown, stained teeth. He suspected the answer might be found in the local water. McKay sent a sample to Harry Churchill, a chief chemist at The Aluminum Company of America. Churchill found the water contained high levels of naturally occurring fluoride.
However, most natural water supplies don’t contain much fluoride. So in the 1930s, researchers led by Dr. H. Trendley Dean at the National Institute of Health looked into adding low levels of fluoride to drinking water and found no negative effects. And in 1945, the first test to fluoridate drinking water took place in Grand Rapids, Michigan.
The hope was that applying fluoride to developing teeth would create a more durable surface that would resist decay. And because fluoride reacts with tooth enamel, making it more resistant to acids and, therefore, less likely to decay and develop a cavity, the fluoridated water worked. Despite the evidence, there was resistance, and conspiracy theories arose about Communists trying to poison Americans en masse. To this day, these concerns over the hazards of ingesting fluoride in drinking water remain unproven, with organizations like the Centers for Disease Control and U.S. surgeon generals supporting this inexpensive way to fight tooth decay in communities.
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