One of the great, less-appreciated advances of the twentieth century was hydraulics. While the concept of using liquids to create force had been around for centuries, a true breakthrough came in 1906, when a system based on hydraulic oil was used to move the guns on a Navy ship, the U.S.S. Virginia. By the 1920s, self-contained hydraulic units were raising and lowering components in everything from cars to machine tools . . . to dental chairs.
Thus, for the first time, dental chairs could go up and down — an enormously beneficial innovation, with that vertical movement powered by hydraulic pressure combined with foot-pump chairs and, later, an electric motor.
Integral to hydraulic lift: hydraulic fluid. This substance was very similar to the brake fluid of today, except that the entire industry referred to it as hydraulic “oil.” That was a misnomer, as the substance had very little to do with the motor oil that most people associate with the term.
After all, unless you like frying your car’s engine, motor oil needs to be changed regularly. But during the period from the 1920s to the 1960s, when hydraulics ruled dental chairs, this oil was good for the entire life of the chair and never needed changing or replacing. It was a onetime buy — the bottle you see here, made by Ritter, likely predates the Great Depression.
It never needed replacing, that is, as long as you kept it from escaping! The problem with the dental chairs of this era — regardless of foot pedal or electric motor, brand or manufacturer — was that they weren’t sealed systems. They worked fine, until and unless they were tilted beyond 45 degrees. When that happened, and it did so more than I care to remember, then — surprise! — that damn fluid spilled. And then the fun really began: It ruined whatever it came into contact with and presented a difficult cleanup challenge.
The happy ending to this story: Dental chairs today are either hydraulics-free or sealed-hydraulics systems — and thus light years better than the ones of old. Nostalgia aside, there were some drawbacks to the “good old days”!
See more of Larry’s Collection at IncisalEdgeMagazine.com