Bob Conte This is an early Celtra Duo case that demonstrates the fragile nature of all of the ceramics we use and process with our CEREC systems. Celtra Duo calls for a very specific firing cycle along with Dentsply’s Celtra Duo firing glaze in order to achieve maximum strength of 370 MPa. The holding temperature of 820 degrees Celsius for 1:30 is critical to the process.
In this case the crown on the left was processed properly initially utilizing the official Celtra cycle for glazing. It looked just like the crown on the right after this initial firing. The author then was hoping to add a little more character and decided on an additional firing, but this time used an old 6 minute Vita glaze cycle that was appropriate for the Akzent stains. The hold temperature for this cycle is 850 degrees Celsius or a mere 30 degrees above the proper cycle. This small variance in protocol sent the ceramic over the edge and I was left with a molten blob.
Lesson learned. Follow the instructions!!!! These ceramics are all meant to be handled properly for long term success.
