There is no single sintering program for dental zirconia: depending on the brand, the grade and the furnace used, the holding temperature ranges from 1,450°C to 1,600°C, the holding time at that temperature lasts from 16 minutes to 2 hours, and the full cycle runs from about 54 minutes to more than 8 hours. This reference brings together, from manufacturer instructions for use that were actually read, the sintering parameters of several zirconia materials used in CAD/CAM laboratories: the discs distributed by Dentev, KATANA Zirconia (Kuraray Noritake), IPS e.max ZirCAD (Ivoclar) and VITA YZ (VITA Zahnfabrik).
Why does sintering temperature and duration change from one zirconia to another?
Batch composition, the percentage of yttrium oxide that stabilises the zirconia, grain size and the commercial grade (high-strength class 5 type II or ultra-translucent class 4) together determine the holding temperature and holding time needed to reach a dense piece with no residual porosity. A furnace able to heat faster or higher, such as a dedicated fast-cycle sintering furnace, can shorten the total cycle without changing the zirconia itself, as long as the program matches exactly the grade being sintered. Two zirconia materials with the same commercial shade can require two different programs if they come from two different manufacturers.
What are the sintering parameters of the zirconia discs distributed by Dentev?
According to the instructions for use from the manufacturer of the zirconia discs distributed by Dentev (ST, SHT, 3D Pro, 4D and UT grades, CE marking, notified body 0197, EN ISO 6872 type II standard), the ST-White, ST-Color and ST-Multi grades sinter at a holding temperature of 1,530°C, and the SHT-White, SHT-Color, SHT-Multi, 3D Pro and 4D grades at 1,500°C. In both cases, the holding time at that temperature is 120 minutes. The temperature rise happens in three stages: from 20°C to 300°C in 28 minutes, then to 1,000°C in 58 minutes, then to the holding temperature in 106 minutes for a single unit or a bridge of 2 to 5 units, or in 133 minutes for a bridge of 6 units or more; cooling from the holding temperature to 20°C then takes 189 minutes. The UT-Multi grade, which comes from a different manufacturer and follows its own instructions for use, sinters at a holding temperature between 1,435°C and 1,470°C, with 1,450°C as the recommended temperature.
What are the sintering parameters of KATANA Zirconia?
According to the sintering schedule published by Kuraray Noritake for KATANA Zirconia, accessed on 30 October 2026, the general 7-hour program, common to the UTML, STML, YML and HTML grades, rises at 10°C per minute to a holding temperature of 1,550°C held for 120 minutes, then cools at 10°C per minute down to 100°C. A fast 90-minute program, limited to cases of up to 3 connected units for the UTML, STML and YML grades, rises in stages to 1,560°C with a holding time of only 16 minutes; the HTML grade follows its own profile on this program, at 1,515°C with a 30-minute holding time. An even faster 54-minute program rises to 1,600°C with a 20-minute holding time for the UTML, STML and YML grades, but does not apply to the HTML grade.
What are the sintering parameters of IPS e.max ZirCAD?
On the Programat S2 furnace product page, accessed on 30 October 2026, Ivoclar states that this furnace reaches a holding temperature of 1,600°C for zirconium oxide materials, with three adjustable heating stages and two cooling stages depending on the grade. For an IPS e.max ZirCAD crown, Ivoclar states that the Programat S2 brings the sintering cycle down to about 75 minutes, compared with 5 to 8 hours with a conventional sintering program on an older furnace. The exact holding temperature and holding time for each cycle are not detailed on that page: to set them, Ivoclar refers to the furnace's instructions for use and to the manual for the ZirCAD grade in use.
What are the sintering parameters of VITA YZ?
According to the VITA YZ instructions for use published by VITA Zahnfabrik, the VITA YZ T and VITA YZ ST grades sinter at a holding temperature of 1,530°C, and the VITA YZ HT and VITA YZ XT grades at 1,450°C. The universal program holds that temperature for 120 minutes, after a rise of about 1 hour 30 minutes, for a full cycle of around 7 hours 20 minutes. A fast sintering program also exists for some grades, bringing the full cycle down to about 80 minutes.
Can one brand's sintering program be used for another brand's zirconia?
No. A holding temperature that is too low or a holding time that is too short leaves the piece under-sintered, porous and less strong; a holding temperature that is too high or a holding time that is too long causes grain growth, which lowers both the strength and the translucency declared by the manufacturer, and can shift the shade. The instructions for use from the manufacturer of the batch actually in hand remain the only reference to follow, even when two zirconia materials share a similar grade name or the same commercial shade: "a temperature or a duration outside the program alters the final properties," as the instructions for use of the discs distributed by Dentev put it. Calibrating the furnace regularly and checking the holding temperature actually reached, for instance with control rings, avoids most gaps between the displayed program and the real temperature inside the firing tray.
- Lowest holding temperature: 1,450°C, VITA YZ HT/XT (VITA Zahnfabrik instructions for use) and UT-Multi distributed by Dentev (manufacturer's instructions for use for the discs)
- Highest holding temperature: 1,600°C, KATANA Zirconia on the 54-minute fast program (kuraraynoritake.com, accessed 30 October 2026) and the Programat S2 furnace (ivoclar.com, accessed 30 October 2026)
- Longest holding time: 120 minutes, ST and SHT discs distributed by Dentev, KATANA Zirconia on the general 7-hour program, and VITA YZ on the universal program
- Shortest holding time: 16 minutes, KATANA Zirconia on the 90-minute fast program (kuraraynoritake.com, accessed 30 October 2026)
- Shortest full cycle found: about 54 minutes for KATANA Zirconia, about 75 minutes for IPS e.max ZirCAD on the Programat S2 (ivoclar.com, accessed 30 October 2026)
- Longest full cycle: at least 8 hours 48 minutes for a bridge of 6 units or more on the discs distributed by Dentev (manufacturer's instructions for use)
Sources
Instructions for use from the manufacturer of the ST, SHT, 3D Pro, 4D and UT-Multi zirconia discs distributed by Dentev, CE marking, notified body 0197, EN ISO 6872 type II standard, summarised in internal sintering documentation.
"Sintering Schedule, KATANA Zirconia Materials," Kuraray Noritake Dental, kuraraynoritake.com/katana/eu/sintering_schedule/, page accessed 30 October 2026.
"Programat S2 Sinter Furnace," Ivoclar, ivoclar.com, page accessed 30 October 2026.
VITA In-Ceram YZ and VITA YZ Solutions instructions for use, VITA Zahnfabrik, vita-zahnfabrik.com, accessed 30 October 2026.
