Let’s Make An Impression: History Of Dental Impressions

When was the last time you had one of those ooey, gooey dental impressions? Perhaps your dentist made a mold, or maybe your orthodontist needed one.

First Ever Dental Impressions

The idea of making dental impressions dates back to the 18th century and German dentists in Prussia. Philipp Pfaff served as dentist to the King of Prussia, Frederick the Great, and described taking impressions in wax. Pfaff had softened the wax in hot water, molded it to the teeth, removed it, then used plaster of Paris to make the cast. Around the same time, German surgeon Matthaus Purmann described using the same type of wax model for making prosthetic teeth.

Fast forward about 50 years to a New York Daily advertisement in 1787, where John Greenwood practiced medicine in Boston before the Revolutionary War, and resumed his career afterwards. In the ad, he promised to make “false teeth” by using beeswax impressions. It is the first known use of a dental model in prosthetic dentistry in America. Greenwood’s son and grandson also became dentists, and used their grandfather’s technique of beeswax molds, but didn’t add plaster of Paris until after 1820.

Levi S. Parmly was another dentist who wrote about use of molds in 1819: “Where the teeth are mostly gone, in both or in either of the jaws, the method is to form an artificial set, by first taking a mould of the risings and depressions of every point along the surface of the jaw, and then making a corresponding artificial socket for the whole.” Parmly considered it one of the great advances in dentistry.

The First Metal Impression Tray

In 1820, a French dentist, C.F. Delabarre, invented the first impression tray—you know, those trays we’ve all come to know and love? So thank Delabarre for that. Rather than using wax alone, he created a metal tray and lined it with wax to get a better imprint. The trays also kept the cheeks from getting in the way of the impression.

Soon, “the manner of obtaining a model” became widely documented in dental textbooks.

Dentists frequently used gold to make crowns and other dental fillings, but plaster was too soft to use to form the gold fixture, so metal impressions were sometimes used. The same technique that was used in iron and brass foundries was used for dentistry too—a plaster model was made the filled with zinc and tin to make the metallic impression.

Later in the 1800’s, gutta percha was used for impressions; it is a natural latex-type material produced by the Palaquium tree, but it was only used for about 25 years because it was too soft.

By the 1870’s trays were made of light upper and lower metal trays that came in three sizes and were used with plaster, very similar to the same method used by dentists today.


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