Custom Zirconia Material Selection

This service lets you specify a zirconia blank outside our standard range. We confirm that we can process it, the lead time for the blank and the cost with you before accepting the case.

What this service is

“Zirconia – let the professionals choose” is for cases where you want a zirconia blank outside our standard range: another brand, another line, or a translucency and shade system that our stocked blanks do not cover. You specify the blank; we design, mill, sinter and finish the case as we do with our own blanks.

Zirconia blanks we stock

Before requesting another blank, you may want to check the lines we use routinely:

• IPS e.max ZirCAD Prime (Ivoclar)
• 3M Lava Plus and Lava Esthetic
• Cercon ht (Dentsply Sirona)
• DD Bio (Dental Direkt)
• Ceramill Zolid, Aidite 3D Pro
• Luxen (Dentalmax)
• Sagemax NexxZr
• Everest and Razor (U&C International)
• Kerox Zircostar
• Copran (Whitepeaks)

Strength, translucency and indications across the zirconia groups are compared in our dental ceramic materials comparison and in 3Y-TZP vs 5Y-PSZ zirconia.

When a non-stock blank makes sense

• Your practice already works with a specific line and wants shade and translucency to match the patient’s existing restorations.
• The case needs a translucency, shade system or layer structure our stocked blanks do not offer.
• The patient or dentist requests a particular brand.

What to send us

• Brand, blank line and version (for example the translucency grade), shade, and disc size if known.
• The manufacturer’s instructions for use (IFU) if available, so we can check indications, minimum thickness and the sintering program.
• The usual case data: scans or impressions, bite, shade, photos.

Process

1. We check that the blank runs on our milling system and sintering furnaces, and that the case is within the manufacturer’s indications.
2. We confirm the lead time for the blank and the cost with you before accepting the case.
3. Once you agree, the case is designed and processed following the blank manufacturer’s instructions.

To ask about a specific blank, contact Khai Nguyen.

Written for dentists and technicians. Khai Nguyen Dental Lab manufactures to clinical prescription only and does not sell directly to patients.

Why “strong zirconia” or “translucent zirconia” is not enough on a prescription

In a survey run in the American Dental Association laboratory (Liao et al., 2023), 9 dental laboratories were asked for zirconia specimens for “posterior” (high-strength) and “anterior” (high-translucency) indications. The 32 specimens from 17 different blanks showed:

• “Posterior” zirconia ranged from 195 to 783 MPa (mean 490 MPa), overlapping heavily with “anterior” zirconia at 320 to 768 MPa (mean 581 MPa).
• Regrouped by yttria content, the 3 mol% materials averaged 584 MPa and the 5 mol% materials 373 MPa.
• The authors attributed the scatter partly to mixed use of 3Y and 5Y blanks, and found strength highly dependent on processing and finishing at the laboratory.

So when you specify a blank outside our range, add the yttria class (3Y, 4Y, 5Y) or the ISO 6872 class the manufacturer declares for that line, alongside brand and line.

ISO 6872 classes and indications

Dental zirconia is a Type II ceramic under ISO 6872. The standard sets classes by minimum mean flexural strength, each linked to a group of indications. For monolithic restorations, ISO 6872:2015 (as summarised by Liao et al., 2023 and Pandey et al., 2024) sets:

Manufacturers state the class in the instructions for use (IFU). Dental Direkt’s IFU, for example, lists DD cubeX² as Class 4 and DD Bio Z, DD Bio ZX² and DD cube ONE as Class 5. For long-span bridges, the blank’s class is the first thing to check.

3Y, 4Y, 5Y and multilayer blanks

More yttria means more cubic phase: the blank is usually more translucent but weaker (see the 3 mol% and 5 mol% figures above). A study of three multilayer zirconia grades from one manufacturer (Kolakarnprasert et al., 2019) measured:

• 5Y-PSZ grade: about 75 wt% cubic phase, mean grain size 4.05 µm.
• 4Y-PSZ grade: about 65 wt% cubic phase, grain size 2.81 µm; translucency similar to the 5Y grade.
• 3Y grade: under 50 wt% cubic phase, grain size 0.63 µm; less translucent than the other two, and the only one showing monoclinic phase after water ageing.

In these blanks the layers differed only in pigments, not composition. Other multilayer blanks change composition through the disc, such as IPS e.max ZirCAD Prime with a 5Y-TZP incisal zone and a 3Y-TZP dentin zone. If you write “multilayer”, name the line so we know which layer carries the load. Background is in 3Y-TZP vs 5Y-PSZ zirconia.

Why each blank needs its own sintering programme

• Properties are reached only after the specified cycle. Dental Direkt’s IFU states that its blanks fulfil their material requirements “after specified final sintering”, with a defined cycle (for example a 120-minute hold at 1450 °C).
• Each disc has its own enlargement factor. The same IFU says the magnification factor is printed on the side of the disc as a code to enter in the software, compensating for sintering shrinkage. That is why the physical disc matters, not just the line name.
• Speed sintering is not always neutral. A meta-analysis by Liu et al. (2023) found no significant effect of speed sintering on flexural strength or fracture toughness, but the CIELab translucency parameter was higher with conventional sintering. A review by Al-Haj Husain et al. (2022) noted that translucency is usually reduced when 3Y-TZP is speed-sintered.

This is why the blank’s IFU helps us check a case before accepting it. Before choosing a non-stock blank, you may want to compare the lines we use: 3M Lava, Cercon ht, DD Bio and ZirCAD Prime. If you still need a blank outside our list, we confirm the lead time and cost with you before accepting the case.

Sources: Liao et al., JADA Foundational Science 2023; Pandey et al., Materials 2024; Kolakarnprasert et al., Dent Mater 2019; Liu et al., Jpn Dent Sci Rev 2023; Al-Haj Husain et al., J Clin Med 2022; Dental Direkt, Instructions for Use DD medical zirconia (Rev.03, 2024).