Die stone materials testing

Comparison of the long-scale accuracy and stability of a range of die stone materials, and the effect of the stone mixing ratio on the accuracy of master models.

Long-scale accuracy

This chart compares gypsum die stone materials from different manufacturers. Again we are only looking and long scale errors here.

Measurements from the master artefact were compared with those from the model, with no impression stage.

Stone mixing ratio

Varying the manufacturer recommended powder/liquid ratio affects the accuracy of the final model.

Adding more water generally reduces errors for these materials.  Lack of abrasive resistance makes the model susceptible to damage, which is likely to be more detrimental to accuracy than the small difference in expansion.

Die stone stability

A stone model was made and the position of each sphere was measured repeatedly over a 16 hour period.

The graph shows the mean position error for all spheres.  Note this is a very small scale.

Most of the expansion has already happened by the time the stone is hard enough to remove from the impression.

Recommended inciseTM materials and accessories

We recommend the following materials and accessories for use with the inciseTM process:

Material / accessory	Renishaw inciseTM recommendations
Impression trays	Perforated metal tray
Tray material	Coltene Whaledent® Affinis™ MonoBody tray material Kettenbach Monopren® transfer tray material
Wash material	Coltene Whaledent® Affinis™ Regular Body wash Kettenbach Panasil® initial contact light or extra light wash
Impression method	Simultaneous application of wash and tray material by dentist and nurse
Model stone	inciseTM model stone matched to the impression
Cement	Kururay Panavia® F Cement

Buy inciseTM-approved materials

Tested and recommended for the inciseTM process, Exact Dental Supplies provides all the products needed to take the most accurate impressions.

www.exactdentalsupplies.com