What is IPS e.max®? IPS e.max® is a trade name for monolithic lithium disilicate ceramic, a biocompatible glass-ceramic material that is renowned for its high mechanical strength, form, function, fit, and aesthetics. It is an affordable alternative to zirconia and porcelain-fused-to-metal restorations. Prosthetics can be built as full-contour monolithic restorations without the need for veneering ceramic. For this reason, the preparation is minimally invasive, while maximizing the aesthetic and strength of metal-free restorations.
What is IPS e.max® CAD? IPS e.max® CAD is an e.max® product that undergoes a milling process where the material is either cut or ground. Cutting uses burrs designed to carve away at the material in a predictable and precise fashion. On the other hand, grinding uses diamond burrs that sand and wear down the material to the desired shape. However, the diamond particles can cause unevenness and as the burrs are worn down, the accuracy is reduced further. According to the Journal of Dentistry, microcracks with depths of 40-60 microns were reported when using the grinding method. IPS e.max® CAD takes the form of blue millable blocks and is said to be, “the world’s best-selling glass-ceramic,” according to its producer, Ivoclar Vivadent®. It is known for its versatility when it comes to applications, its comprehensive range of processing options, and its strength. Clinical StudiesMore than 10 years of ongoing quality testing has proven clinical long-term success and scientifically documented results. In regards to fracture toughness and biaxial flexural strength, a 2010 document published by Ivoclar Vivadent® found the toughness to be 2.25 megapascals (MPa) and strength to be 360-400 MPa. This combination of fracture toughness and flexural strength is particularly desirable in minimally invasive dentistry. In terms of survival rate, an eight-year independent study by the Clinicians Report® documented a 95% survival rate with a 5% failure rate due to breakdown in cementation. However, there was no breakdown reported in the lithium disilicate material itself. Other clinical reports found IPS e.max® CAD to deliver a 97.2% survival rate over a ten-year period.  Two-Step Crystallization Process E.max® CAD can not be milled in its fully crystallized state because it would be too hard and cause the burrs to wear down too quickly. To combat this, the material, known as lithium metasilicate in its initial form, is partially crystallized at the factory to make it millable. Lithium metasilicate is softer than its final form, lithium disilicate, with a flexural strength of 130 MPa. This allows the product to be milled with diamond burrs before going through its final crystallization cycle. The two-step crystallization method results in the formation of shorter and smaller crystals, which is the reason for less resistance to fractures and the drop in strength compared to pressed e.max®. Maximum VersatilityMilled e.max® covers an unrivaled scope of applications in computer-assisted design and manufactured (CAD/CAM) glass-ceramics:
 Versatile Processing OptionsThe wide range of products covered by e.max® CAD offers flexibility when it comes to processing methods, allowing the technician to either prioritize aesthetics over efficiency or vice versa:
Comprehensive Shade RangeMilled e.max® blocks are available in four different levels of translucency plus the special Impulse shade. The comprehensive range enhances flexibility and shade matching to provide maximum aesthetics. IPS e.max® CAD High Translucency (HT) blocks are suitable for smaller restorations, such as inlays or onlays. Given their high translucency, HT restorations seamlessly blend in with the natural dentition. IPS e.max® CAD Medium Translucency (MT) blocks provide more brightness than HT restorations and more translucency than LT restorations. IPS e.max® CAD Low Translucency (LT) blocks are characterized by their lifelike brightness and chroma and are suitable for fabricating larger restorations, such as posterior crowns. IPS e.max® CAD Medium Opacity (MO) blocks are ideal for slightly discolored frameworks. IPS e.max® CAD Impulse (I) blocks hold opalescent properties, which are ideal for veneers in light tooth shades.  How Can The Dental Lab Help?The Dental Lab is a proud provider of both IPS e.max® CAD and its pressed counterpart IPS e.max® Press. Our skilled technicians are experienced in both pressing methods as well as using CAD/CAM for milling. Contact us today to send a case. Keywords:
IPS e.max, IPS e.max CAD, milled, milling, lithium disilicate ceramic, ceramic, restorations, veneers, crowns
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