ANSWERS

How thick should an e.max crown be?

An e.max lithium disilicate crown needs 1.0mm minimum thickness on axial walls and 1.5mm on occlusal or incisal surfaces for posterior cases. Anterior cases tolerate 0.8mm in non-load-bearing zones. Ivoclar Vivadent's published prep guidelines (the e.max manufacturer) flag anything under 1.0mm occlusal as a fracture...

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Why it works this way

Manufacturer-published minimum thickness for e.max

Ivoclar Vivadent, the manufacturer of IPS e.max, publishes the prep guide that every lab works from. Their floor: 1.0mm axial wall, 1.5mm occlusal reduction on molars and premolars, and 1.0mm incisal reduction on anteriors. Anterior facials can go to 0.8mm in non-functional zones. The flexural strength of pressed lithium disilicate sits at roughly 400 MPa, which is what lets the material survive at those thicknesses, but the number assumes the prep hits the minimum. Under 1.0mm occlusal on a second molar is where fractures show up in the literature.

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What happens if the e.max crown is milled under the minimum thickness?

Fractures show up between three and eighteen months on posterior cases prepped under 1.0mm occlusal. The crown survives initial seating and short-term function, then fails under repeated load. Ivoclar's prep guide flags this directly. At Dani Dental the CAD technician checks reduction on every case before the design hits the mill. If clearance is short, the dentist gets a same-day call from the technician on the case, not a generic lab rep, so the prep can be adjusted before a crown ships that will fail.

Can e.max be used for full-arch or bridge cases?

e.max press handles three-unit anterior bridges through the second premolar at standard thickness. Posterior bridges and full-arch cases shift to zirconia because lithium disilicate flexural strength caps around 400 MPa, while zirconia holds at 1200+ MPa. Dani Dental's All-on-X workflow defaults to zirconia for the final prosthetic for that reason. For single-unit anterior esthetics where the prep supports it, e.max remains the material of choice, often layered for the high-shade-match cases prosthodontists send.

How long does an e.max crown case turn at Dani Dental?

Single-unit e.max crowns ship on a standard turnaround window from receipt of a clean intraoral scan. The technician assigned to the case is reachable by direct line for prep questions, shade calls, or contact adjustments. If the prep is short on reduction the call goes out same day so the dentist can adjust before milling. Multi-unit anterior cases with custom layering run longer because the ceramist builds shade in layers, which is the work the case is paying for.

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This answer is one piece of a larger workflow. The pillar page covers materials, turnaround, and how we build the case to your specification.

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