Lithium Disilicate CAD/CAM Blocks: KrystaFree and the State of the Market
Lithium disilicate remains one of the most clinically relevant materials in the dental lab — strong, highly aesthetic, and the go-to for anterior veneers, crowns, and inlays where optical properties matter. The CAD/CAM market for lithium disilicate blocks has expanded significantly, with alternatives to the original IPS e.max CAD now available at various price points. Here's what you need to know.
Why Lithium Disilicate
Lithium disilicate's clinical appeal comes from its combination of adequate strength for most single-unit restorations and excellent light transmission/depth. It transmits and reflects light similarly to natural enamel — something zirconia, despite its advances, doesn't fully replicate. For anterior cases and premium aesthetics, this material category is still the standard of care.
Key properties:
- Flexural strength adequate for single-unit crowns and veneers (not appropriate for posterior bridges under heavy load)
- Excellent translucency and polychromatic optical effect
- Requires wet milling — cannot be milled dry
- Requires crystallization firing after milling to develop full properties
- Can be etched and bonded, which is critical for thin veneer applications
The Two-Stage Milling/Firing Process
Most CAD/CAM lithium disilicate blocks are supplied in a pre-crystallized (blue phase or lithium metasilicate) state — this softer, more machinable phase mills efficiently without excessive bur wear. After milling, the restoration is fired in a porcelain furnace at the crystallization temperature, which transforms the material to its final lithium disilicate crystal structure and develops full strength and translucency.
The firing stage also allows color adjustment through the use of compatible staining and glazing materials.
IPS e.max CAD — The Reference Product
Ivoclar's IPS e.max CAD is the most extensively documented lithium disilicate CAD/CAM material, with the largest clinical evidence base. It comes in a wide range of shades and translucency levels (LT, MO, HT, MT, BL) and has validated workflows with most major CAM platforms. It's also the most expensive option in the category.
KrystaFree — The Competitor Worth Knowing
KrystaFree is a lithium disilicate CAD/CAM block that enters the market as a cost-competitive alternative. For labs looking to reduce material costs on glass ceramic cases without abandoning the lithium disilicate workflow, KrystaFree is worth evaluating. The key questions when evaluating any e.max alternative:
- What are the validated crystallization parameters? (Peak temperature, hold time — these must match your furnace capability)
- Is there an independent shade guide, or does it map to VITA?
- What milling strategies have been validated, and are they available in MillBox or your CAM platform?
- What is the flexural strength post-crystallization?
Any alternative lithium disilicate product needs independent validation in your lab before going into clinical production — run test firings, verify fit and shade, and confirm the properties match the spec sheet.
Working with Glass Ceramic Blocks: Lab Reminders
- Wet mill only — no exceptions; glass ceramics will develop micro-fractures dry-milled
- Use glass ceramic-specific burs; zirconia burs are not appropriate
- Handle pre-crystallized (blue phase) blocks carefully — they're brittle before firing
- Verify your crystallization program in the furnace; temperature accuracy matters for final properties
- Staining and glazing is done after crystallization; sequence matters
Application Guide
| Restoration Type | Lithium Disilicate Suitable? | Notes |
|---|---|---|
| Anterior veneers | Yes (ideal) | Optimal optical properties; etchable for bonding |
| Anterior crowns | Yes | Excellent aesthetics; verify occlusal clearance |
| Premolar crowns | Yes | Adequate strength for most cases |
| Molar crowns | Case-by-case | Check occlusal forces; bruxers may need zirconia |
| 3-unit bridges | Limited | Connector dimensions critical; posterior bridges higher risk |
| Implant-supported crowns | Yes (with caveats) | Cement-retained preferred; screw access may compromise material |