Zirconia Processing Expert: Cercon xt Multilayer a “Game-Changer”
The Cercon all-ceramic CAM system was introduced to the dental market in 2001 and with it the first economically viable process for the production of dental zirconia crowns and bridges. Since then, the Cercon line has evolved with Cercon base colored, Cercon base light and medium, Cercon ht, Cercon ht light and medium, Cercon ht True Color Technology, Cercon ht and Cercon xt for open systems, and now Cercon xt Multilayer (ML) from Dentsply Sirona.
Throughout that time, Jack Marrano, CDT, estimates that he likely has processed more zirconia than anyone in North America.
“The advances in zirconia materials have been so incredible,” says Marrano, Director of Signature Prosthetics for Absolute Dental Services, which has three locations in North Carolina and one in South Carolina. “The industry focused too much on strength in the early years, with the materials reaching as high as 1500 MPa, and with that came ugly levels of opacity and the need to externally or internally stain. We then went in the opposite direction ended had zirconia materials with flexural strength as low as 500 MPa, which led to brittleness and fractures in the mouth. Finally, we have found the sweet spot, which is 750 MPa to 1200 MPa, and now the introduction of multilayer zirconia has improved our options even more.”
Marrano notes that the techniques that have been necessary to optimize the esthetics of zirconia in the past have been inefficient because they are redundant.
“If we have the computing capability to design that restoration in full contour, but we then remove all of that valuable information such as contacts, facial position, and incisal edge, and replace it with layered ceramic, that is a redundancy and an inefficiency in the workflow,” he says. “It is ideal to maintain all that information with minimal post-process finishing. Multilayered zirconia is layered within the puck and preshaded, so we can design it in full contour and maintain that throughout the process.”
Some multilayer zirconia products have a limited range of shades, but Cercon xt ML features True Color Technology that accurately matches all 16 VITA* shades and is available in BL2.
“Having the entire range makes it applicable and optimal in any situation,” Marrano says. “When you only have a selection of five shades, you can design in full contour, but you really need to work harder in post-processing to achieve the correct shade. With Cercon xt ML, if a case requires A2, you mill it in A2. You can apply additional characterization, but you have your base, which is most important.”
Cercon xt ML also has the same sinter cycle as Cercon xt and Cercon ht, so users can sinter all Cercon restorations the exact same way.
“We have six sintering ovens, and at times we have been beyond capacity because we had different types of zirconia that required different cycles,” Marrano says. “With the Cercon line, various types of zirconia restorations can be sintered on the same tray.”
With those factors plus Cercon xt ML’s 750-MPa strength and approximately 49% translucency, dentists have taken notice of the improved quality of their restorations.
“They love it,” Marrano says. “I often challenge dentists to differentiate between multilayer zirconia and all-ceramic crowns. Not only can they not tell the difference, but they usually pick the multilayer zirconia as the more esthetic one. You cannot pick this out in the mouth, so it has been a real game-changer.”
Dentsply Sirona Laboratory
*VITA is a registered trademark of VITA Zahnfabrik H. Rauter GmbH & Co. KG.