Digory: A 3D Printed Alternative to Ivory

For a long time, ivory was considered a valuable material due to its rarity and was used, among other things, for various art pieces. The material is obtained from the tusks and canines of various species, prominently Asian elephants. In order to protect these animals, the ivory trade has been banned since 1989. The EU Commission is also considering a ban on intra-European trade in antique ivory in order to counteract criminal activities. The Technical University in Vienna has now developed the material “Digory” together with Cubicure GmbH , which thanks to SLA 3D printing, enables the restoration of existing objects and is deceptively similar to ivory. The project was created in cooperation with the Art and Monument Preservation of the Archdiocese of Vienna and the Addison restoration studio in Vienna.

Alternatives for restoration

Mammoth ivory was used to carve figures more than 35,000 years ago. In the course of history, the material was used by a large number of cultures for the production and decoration of pieces of jewelry and in Christianity it was often used in sacred objects. Various alternatives made of mussels, bones or plastics have been used for restoration in recent years. However, there was no material among them that was 100% convincing. In addition, many of these materials are only available on the market in large quantities and are therefore of no interest for repairing individual parts for economic reasons.

Shrine with ivory decoration from the 17th century (Photo Credit: Stephan Doleschal)

The starting point for the project was a shrine from the 17th century, which is located in a church in Mauerbach, Lower Austria. “It is decorated with small ivory ornaments, some of which have been lost over time. The question was whether they could be replaced with 3D printing technology, ” said Jürgen Stampfl from the Institute for Materials Science and Technology at the Vienna University of Technology.

Digory – synthetic resin with calcium phosphate particles

The material “Digory” is the result of a collaboration with the TU spin-off Cubicure. For its development, the team was able to fall back on its expertise with ceramic materials for dental technology. The Digory consists of synthetic resin with calcium phosphate particles and silicon oxide powder and is cured in the desired areas using the stereolithography process. Compared to other alternatives, the right amount of calcium phosphate can be used to produce a translucent material. A property that distinguishes ivory and is therefore essential for aesthetics.

Confusingly similar: ivory on the left, Digory on the right (Photo Credit: TU Vienna)

“With our specially developed 3D printing systems, we process different material formulations for very different areas of application, but this project was also something new for us,” says Konstanze Seidler from Cubicure. “In any case, it is further proof of how diverse the possible uses of stereolithography are.” A major advantage of using 3D printing for restorations is the ability to reproduce even the finest details. After printing, the color of the parts is reworked in order to preserve the color structures of the ivory. To do this, the team uses an inexpensive and environmentally friendly coloring agent – black tea. The manufacturers hope that the material will establish itself on the market as a high-quality ivory substitute. You can find out more about this project by reading the full paper HERE.

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* Cover picture credits: Archdiocese of Vienna