Timeline of All Potential Types of Autopsy Records, and Molds and Casts

Type writers entered the public domain in the 1870s. Therefore, typed autopsy records can be expected as early as the 1870s. Even after the invention of type writers, it would not be unusual for professionals to prefer taking hand written notes during the procedure and then writing a formal documentation later using a machine. Autopsies can be messy and dusty procedures and machines get in the way.

The modern computer was invented as early as the 1940s, but it was not until the 1970s that computers were manufactured for consumer use (Daskeyboard, “Typing Through Time.”). Therefore digital copies of notes can be expected starting as early as the 1970s.

Plaster of Paris molds and casts have been made since the 15th century, but the field of paleopathology did not emerge until the turn of the 20th century.

After latex, the use of plaster for cast resurged. However, this time dental plaster with a finer grain was used. The finer gain size allowed for more details to be captured (Turner, Biological Anthropology and Ethics, 91-94).

Around the 1950s, it also became common to use polyester and epoxy for making casts. Later these materials became the “overwhelming choice (Turner, Biological Anthropology and Ethics, 94).” Not only are polyester and epoxy more rigid plastic resins, thus not as likely to penetrate the surface foramina, but they created highly detailed casts that were also highly stable. On the other hand, epoxy casts were very expensive and they produce a chemical bi-product and heat during the curing process. This chemical bi-product can permeate the silicon mold, destroy its elasticity and over time will accelerate the degradation process of the whole cast. Lastly, the silicon cast is susceptible to shrinkage since it cures by evaporation. According to Janet Monge and Alan Mann, it is not uncommon to have 10% or more shrinkage as well as some distortion. It is possible to prevent such dimensional distortion by applying a tempering agent such as fiberglass or talc (Turner, Biological Anthropology and Ethics, 91-94).

Room Temperature Vulcanization (RTV) silicon rubber had great flow and the ability to capture finer details. Unfortunately, due to the great flow, the silicone rubbers also tended to “penetrate the surface foramina on a bone [and thus] when the mold is pealed off the fossil, many of these will break off and remain in holes (Turner, Biological Anthropology and Ethics, 93-94).” This ultimately would cause irreversible change to the texture and anatomy of the fossil. In some cases, this material was also noted for leaving chemical residue on the fossil (Turner, Biological Anthropology and Ethics, 93-94).

Polyurethanes require a releasing agent between the mold and the casting agent so to prevent the materials from bonding. Unfortunately, the releasing agent also reduces the accuracy and quality of the details. Polyurethane molds also tend to shrink. According to Monge and Mann, they shrink roughly the same amount as the epoxy molds, but unlike the epoxy molds they tend to have dimensional stability. In other words, they shrink the same amount in all dimensions (Turner, Biological Anthropology and Ethics, 91-94).