IPS e.max is a lithium disilicate glass ceramic that has optimized translucency, durability, and strength for full anatomical restorations. It combines lifelike materials and fracture resistant properties. This material is the most esthetic, while still offering superior durability featuring 500 MPa of flexural strength. Due to use of new technology and optimized processing parameters, IPS e.max is more evolved than previously available lithium disilicate ceramics and has increased 2.5 to 3 times in strength than other glass ceramic options. It is an excellent choice of material for anterior esthetics or posterior function. Emax is great for single crowns, veneers, inlays/onlays, and specifically anterior cases. It is not recommended for bridges as they do not allow for adequate connector heights with this material.
Anterior full coverage crowns require a chamfer or shoulder margin. A circular shoulder is prepared with rounded inner edges or a chamfer at angle of 10-30°; the width of the shoulder or chamfer is approximately 1mm. Facial reduction is 1.5-2mm 1-1.5mm lingual contact clearance. Incisal reduction is 1.5-2mm with rounded internal line angles and at least 1mm wide on the incisal edge to permit optimum milling during CadCam processing.
Posterior full coverage crowns require a chamfer or shoulder margin. A circular shoulder is prepared with rounded inner edges or a chamfer at angle of 10-30°; the width of the shoulder or chamfer is approximately 1mm. Occlusal reduction 1.5-2mm, axial reduction (buccal, lingual, interproximal) is 1.5 with rounded internal line angles.
Emax can be cemented using resin reinforced glass ionimer such as RelyX Luting cement. It can also be bonded using a resin cement, such as RelyX Unicem or Ultimate, when extra strength is needed due to lack of retention on prep. Manufacturer Ivoclar Vivadent recommends using Multilink Automix for maximum strength of the restoration overall.
If adjustments are needed, use fine diamonds with air and water spray with light pressure. Be sure to always remove the crown when adjusting. To polish the roughened surface, use Brasseler Dialite system or similar substitute.