What to Decide Before You Order
1. How many units, and where?
Survival data separates sharply between single crowns and bridges, and this directly affects material choice.
| Restoration | 5-Year Survival (monolithic zirconia) | Reference point |
|---|---|---|
| Single crown | ~96.8% | Comparable to layered zirconia 97.3% and metal-ceramic 97.1% |
| Multi-unit bridge | ~87.9% | Lower than layered zirconia bridges at ~92.9% |
2. Anterior or posterior?
Zirconia grade is a trade-off between strength and translucency. Yttria content (Y₂O₃) controls this.
| Grade | Typical flexural strength | Translucency | Where it fits |
|---|---|---|---|
| 3Y-TZP | ≥1,100 MPa | Lowest | Posterior crowns, multi-unit posterior bridges, heavy occlusion |
| 4Y-PSZ | ~800–1,000 MPa | Medium | Posterior single crowns, short-span bridges, premolar area |
| 5Y-PSZ | ~600–800 MPa | Highest | Anterior crowns where esthetics outweigh maximum strength |
The reason 5Y is more translucent is also the reason it's weaker: the microstructure shifts toward a cubic-dominant phase, which reduces transformation toughening — the mechanism that gives 3Y its fracture resistance. For a bruxism patient, choosing 5Y for the esthetic win is a decision — not a free upgrade.
> On bruxism specifically: the evidence base is thinner than most product pages admit. A 2022 systematic review flagged one included study where survival in bruxism cases dropped sharply with small sample size. We treat bruxism as a reason to prefer 3Y-TZP and recommend a night guard — not as a reason to assume any zirconia is "bruxism-proof."
3. Preparation requirements
For posterior all-ceramic restorations, Abdulmajeed's clinical review in Inside Dentistry gives the following occlusal and axial reduction targets:
| Grade | Occlusal and axial reduction |
|---|---|
| 3Y-TZP | 0.8–1.0 mm |
| 4Y-PSZ | 1.0–1.2 mm |
| 5Y-PSZ | 1.2–1.5 mm |
Monolithic zirconia can be fabricated with surfaces as thin as 0.6 mm, which gives you flexibility when prep space is tight. That figure is not universal, though — the minimum thickness rises as yttria content increases, so a 5Y-PSZ restoration needs more reduction than a 3Y-TZP one to compensate for its lower strength. A heavy chamfer or rounded shoulder is preferred over a knife-edge margin; sharp internal line angles and abrupt transitions should be avoided, because they concentrate tensile stress. If you want to run a case under tight occlusal clearance, send the scans and we'll flag whether it's workable before milling.
Materials We Stock
We keep both domestic and imported zirconia blocks on hand so we can match your material preference. From our material catalog:
- Zirconia blocks — Aidite, Yucera (domestic); Wieland, Zirkonzahn, 3M Lava, Ivoclar (imported)
- Veneering porcelain (for layered or cut-back cases) — Ivoclar, Shofu, Noritake
- Luting / bonding reference — recommendations provided per block IFU
For every case, we can supply:
- Zirconia block brand, grade, and batch number
- Material certificate / certificate of conformity
- Sintering curve log (temperature profile and dwell times for the batch)
Pricing depends on grade, number of units, and surface finish; request our B2B price list from your account manager.
Surface Finish: Why It's Not Just a Cosmetic Choice
Both polishing and glazing produce a smooth, hygienic surface. But their effect on strength is not symmetric. A 2018 Journal of Dental Research study on 5Y-PSZ measured flexural strength (4-point bending) under three finishes:
| Finish | 5Y-PSZ flexural strength (4-point bending) |
|---|---|
| Polished | 467 ± 38 MPa |
| Sandblasted | 274 ± 55 MPa |
| Glazed | 211 ± 21 MPa |
That's roughly a 55% strength drop when 5Y is glazed versus polished. For 3Y-TZP the gap is narrower, but the direction is the same. We default to mechanical polishing on monolithic cases and reserve glazing for cases where surface characterization matters more than peak strength. If you have a preference, tell us; we'll follow it and log it with the case.
One operational note that matters chairside: if you adjust occlusion after seating, re-polish the adjusted surface. A ground, un-polished zirconia surface is both rougher on the opposing dentition and more prone to crack initiation. We supply polishing wheel recommendations by material brand on request.
Antagonist wear
On enamel wear against opposing teeth, a 2024 network meta-analysis reported monolithic zirconia produced about 40 µm of additional enamel wear versus natural enamel, compared with roughly 82 µm for metal-ceramic. That's a point in zirconia's favor. We'll also tell you honestly that an earlier in-vitro study found results that pointed in a different direction regarding polished vs. glazed, so the "polish or glaze for minimum wear?" question doesn't have a settled answer. What is settled: a rough, un-polished surface is worse for the opposing dentition than either.
Cementation: What We Supply, What You Do
Cementation is a chairside procedure performed by the clinician — we don't do it, and we don't tell you how to do your job. What we do:
- Ship each case with a cementation recommendation keyed to the specific zirconia block (per the manufacturer's IFU).
- Provide block IFUs in English if you don't have the brand on file.
- Note any case-specific concerns (short clinical crown, short axial walls, divergent prep) that may affect retention.
In practice, most monolithic zirconia single crowns can be cemented with conventional glass ionomer or resin-modified glass ionomer when retention form is adequate. Adhesive bonding with a resin cement and an MDP-containing zirconia primer is the fallback when retention is compromised. The clinical community has converged on this split — if your retention form is good, the extra time of a bonded protocol is often unnecessary.
Regulatory and Standards Context
Terminology on this page matters because the wrong wording can create compliance exposure. A few points we hold to:
- Zirconia dental restorations in the U.S. are cleared under 21 CFR 872.6660, product code EIH, Class II. The 510(k) decision is "Substantially Equivalent" — not "FDA approved." We don't use the "FDA approved" phrasing because it's not what the clearance says.
- In the EU, custom zirconia restorations are handled under MDR Annex XIII (custom-made device route), Class IIa. We complete the MDR custom-device notification and issue a per-case custom-made device statement.
- The relevant material standard is ISO 6872:2024 Dentistry — Ceramic materials. For posterior multi-unit bridges, zirconia should meet Class 5 (≥800 MPa flexural strength).
Our registrations and certifications
- FDA establishment registration + device listing (custom dental restorative material)
- EU MDR custom-made device notification
- UK MHRA registration
- ISO 13485 quality management system
What to Ask Your Supplier (Procurement Checklist)
A finished crown without supporting documentation is a black box. For your records and for diagnosing anything that goes wrong clinically, we recommend asking for the following with every case — not just ours.
Material
- Block brand and grade (3Y / 4Y / 5Y)
- Batch number and expiration
- Material certificate / certificate of conformity
Processing
- Sintering curve log for the batch
- Surface finish applied (polished / glazed / cut-back + layered)
- Shrinkage compensation factor used in CAD
Quality
- QC inspection record (margin fit, occlusal clearance, contour)
- Technician and inspector sign-off
- Reject / remake notes if the case was reworked
Compliance (for export cases)
- FDA registration proof (U.S.)
- MDR custom-device statement (EU)
- ISO 13485 certificate (if required by your jurisdiction)
Design artifacts
- Final approved STL
- Margin-line verification
- Occlusal clearance map (if available)
We supply all of the above on request. Every case is bound to a unique barcode that links the technician, equipment, material batch, and QC results, so if you ever need to trace a case, we can retrieve the full production record.
How We Make a Monolithic Zirconia Crown
We're a full-service dental lab, not a middleman. For a zirconia crown-and-bridge case, the full workflow runs under one roof:
Case intake — digital files (STL/PLY/DCM) by email or secure transfer, or physical impressions with a prepaid shipping label for established accounts.
CAD design — reviewed by senior designers; design file sent to you for approval on request before milling.
CAM milling — multi-axis dental mills; shrinkage compensation set per material batch.
Sintering — zirconia-specific furnaces running validated temperature profiles per block manufacturer's instructions; sintering logs retained.
Finishing — mechanical polishing (default) or glazing (on request); margin and contour refined by hand.
Multi-stage QC — in-process checks at the end of each department (sintering, finishing, final), with the final release performed by independent QC staff, not the technician who built the case.
Packaging and shipment — bar-coded individually, cushioned for fragile items, scan-linked to the courier tracking number.
Everything above happens at our Shenzhen and Huizhou facilities. We don't re-outsource cases.
Who's actually doing the work
- Around 460 full-time staff, including ~100 in CAD, ~70 in milling, ~70 in porcelain/metal (for layered cases), ~25 in QC, and ~40 in case coordination and customer service
- A trained reserve pool of ~50 production staff to cover peak season
- Normal-season capacity around 8,000 single zirconia crowns and 2,000 zirconia bridges per month; peak-season capacity around 15,000 single crowns and 3,000 bridges per month
Delivery timelines are counted in working days from the point we have everything we need (design approved, materials confirmed). Waiting on your approval or missing files doesn't eat into your production clock.
- Standard zirconia crown and bridge: ~2–3 working days of lab production time
- Complex implant or full-arch cases: ~5–7 working days of lab production time
- Rush service: available at no extra charge for established customers whose monthly volume is below 10 units (per our standing policy); larger rush requests are handled case by case
Quality Management and What Can Be Audited
Because every production step is in-house, we can show you data for every stage. In practice:
- Per-case traceability: unique barcode links technician, equipment, material batch number, and all QC checkpoints. Production records are retained for three months by default (extensions available on request).
- Internal rework rate: tracked monthly by our lab manager; current overall rework rate runs around 2–3%.
- Supplier audits: we support client audits of our quality system, production records, and material-handling records. Site visits in Shenzhen or Huizhou can be arranged through sales; video inspections of specific lines are also available.
- Remake policy: the great majority of lab-origin remakes are free of charge — margin gaps, open contacts, high occlusion, poor seating, incorrect shade, or clear esthetic defects. Items outside the free-remake scope include changes you request after approval (e.g., changed shade, changed material) and cases where the submitted impression was flagged by us as unsuitable and you asked us to proceed anyway. Where repeated remakes still can't resolve the issue, we offer a refund.
- Monthly reports: on-time rate, rework rate, and complaint rate can be delivered as a customized monthly report under an agreement.
Working with Istar
Starting a new relationship
- Send a test case — digital or physical — through your preferred channel. We don't require a minimum order volume to try us.
- Every account gets a dedicated case manager and a customer service lead who stays with you.
- Standard reply time within our working hours (China time, 9:30–18:00) is under an hour; outside working hours, depending on the time zone difference, up to 7–8 hours, and no longer than 12 hours.
- WhatsApp groups are set up per account for case discussion, try-in feedback, and technical follow-up.
Agreements
- NDAs, quality agreements, and supplier agreements can be signed on request.
- Supplier qualification questionnaires and annual audits can be completed.
- B2B price lists, product catalogs, and material lists are available from your sales manager.
Visiting us
- Factory tours and video audits of the Shenzhen and Huizhou lines are open to clinics, labs, and DSOs. Book through your sales contact.
FAQ
Can a monolithic zirconia crown be used in the anterior region? Yes, with 5Y-PSZ (high-translucency zirconia). The esthetic result is good for most patients but will not match the depth of a hand-layered restoration. For a demanding anterior case where esthetics are the priority, we usually recommend a cut-back and layered design on a zirconia core instead.
Is monolithic zirconia the best option for a patient who grinds? 3Y-TZP is the material of choice for heavy occlusion because of its higher flexural strength and transformation toughening. We also recommend a night guard. We won't tell you zirconia is grinding-proof — the literature doesn't support that claim.
What happens if the crown chips? Monolithic zirconia has no porcelain veneer to chip. If the zirconia body itself fractures — rare, especially in 3Y — intraoral repair with composite is a weak fix. Replacement is usually the right call.
Can you match a specific zirconia block brand we use at the clinic? Yes. Tell us the brand and grade in the prescription; we'll confirm stock, run the case on that material, and ship the material certificate with the restoration.
Do you accept digital cases? Yes, STL / PLY / DCM files are our default input. If you work on a specific CAD platform or scanner, let us know and we'll confirm compatibility.
Can we audit your facility? Yes, including on-site visits, video inspection of specific production lines, and supplier questionnaires. Factory visits are coordinated through your sales contact.
Can you provide monthly performance data for our accounts? Yes — on-time rate, rework rate, and complaint rate can be delivered as a customized monthly report.
Request a Quote or Test Case
Send us your scans, prescription, and shade preference. For a first case, we'll confirm feasibility, provide a design preview if you ask for one, and lock in a delivery date before we start milling. We'll ship the restoration with the material certificate, QC record, and any compliance documents you need.
Contact your account manager through our sales team to:
- Request the B2B price list and material catalog
- Start a test case (no minimum order)
- Schedule a factory visit or video audit
- Discuss NDAs, quality agreements, or supplier onboarding
Istar Dental Lab — direct manufacturing of zirconia restorations since 2012, serving dentists, clinics, DSOs, and partner labs in the U.S. and Europe.