LaMoreaux

Jessie Castle LaMoreaux, the first woman dentist to practice in Texas, c.1900.

The curve on a graph, first described by Robert Stephan in 1943, showing the fall in pH below the critical level of pH 5.5, at which demineralization of enamel occurs following the intake of fermentable carbohydrates, acidic liquids, or sugar in the presence of acidogenic bacteria. After consumption, there is an elimination of the acid and a return to normal saliva or plaque pH, at which point repair of any destruction of the enamel structure takes place (remineralization). Repeated intakes of fermentable carbohydrates cause the low pH to be maintained for longer periods, thereby not allowing remineralization to take place.

Did you know?

Decalcification of teeth occurs when the pH in the oral cavity is less than 5.5 Below the so-called “critical pH” at which point it is postulated enamel built with hydroxyapatite dissolves.

Fluoroapatite has a critical pH of 4.5

Fluoroapatite is present in human teeth that have been exposed to fluoride ions, for example, through water fluoridation or by using fluoride-containing toothpaste. The presence of fluorapatite helps prevent tooth decay or dental caries, it makes tooth structure more resistant to additional caries attack.

It takes only 1 to 3 min to decrease pH below 5 of plaque exposed to sugar.

It takes 30-60 minutes for your saliva to get you back to the safe zone.

Large (Wikimedia)

So I may have mislead you a little bit yesterday, dear reader, in my enthusiasm against dentistry.

In fact, my oral surgeon was wonderfully efficient—and he even has some interesting thoughts on German Expressionism (though he chose to share them with me just as the nurse applied the anesthetic, so I’m afraid my contributions amounted to: “no, don’t like…Paul Klee…not fond…Klee…funny angels…don’t like…”).

So to make my amends to the profession, here we have an 1889 painting by Gunnar Berndtson of a dentist named Matti Äyräpää.

The specialized chair and adjustable lamp, the delicate tool in Äyräpää’s hand, the washbasin, the little jars on the cabinet in the back, even the complacence of the patient—look how relaxed her hand is on the arm of the chair, as opposed to yesterday’s startled victim—all lend a sense of scientific precision and modernity to the scene.