How is an e.max crown cemented?

No. Conventional glass ionomer and zinc phosphate cements are not approved by Ivoclar for IPS e.max lithium disilicate restorations. Both materials lack the bond strength to support the restoration under occlusal load and will lead to debonding, fracture, or both. The minimum acceptable cementation is self-adhesive resin cement, and only on retentive preparations at or above 1.5mm wall thickness. Anterior cases and thin-walled preparations require full adhesive resin bonding with hydrofluoric acid etch and silane treatment per the manufacturer's protocol.

Ivoclar specifies 1.5mm minimum occlusal and axial wall thickness for posterior IPS e.max crowns cemented with self-adhesive resin cement. For adhesively bonded cases the minimum drops to 1.0mm occlusal in select scenarios, though most clinical guidance recommends staying at 1.5mm for predictability. At Dani Dental we flag any preparation that comes in thinner than 1.5mm on the case slip so the restorative dentist can either rebuild the prep or commit to the adhesive bonding workflow before seat day.

Twenty seconds. Ivoclar's IPS Ceramic Etching Gel (5% hydrofluoric acid) is applied to the intaglio surface for exactly 20 seconds, then rinsed thoroughly with water spray and air-dried. Over-etching past 60 seconds degrades the lithium disilicate crystal structure and reduces bond strength rather than improving it. After etching, the surface is silanated with Monobond Plus for 60 seconds and air-dried before the resin cement is loaded into the crown for seating.