What is IPS e.max®?E.max is a trade name for monolithic lithium disilicate ceramic, a biocompatible glass-ceramic material that is renowned for its high mechanical strength, fracture toughness, form, function, fit, and aesthetics. Its true-to-nature shade behavior and optimum light transmission combined with its resistance to fractures, chips, or cracks results in long-lasting and lifelike aesthetic restorations. In addition, it is an affordable alternative to zirconia and porcelain-fused-to-metal dental corrections. Given their high flexural strength of 360 – 400 MPa, IPS e.max® restorations also offer flexible cementation options: adhesively, self-adhesively, or conventionally. The strength also enables very thin restorations to be fabricated without the risk of fracturing. 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. There are two types of IPS e.max®: Press and CAD.  IPS e.max® PressIPS e.max® Press is lithium disilicate that is pressed through a three-step process:
Pressing is the desirable production method as it enables the technician to get the full benefits of the material and produce several restorations in a single cycle. The 2010 Ivoclar Vivadent® document stated that pressed IPS e.max® has a fracture toughness of 2.75 MPa and a flexural strength of 470-500 MPa. Over ten years of clinical long-term success has documented e.max® Press to deliver a 97,8% survival rate Press ingots are available in seven different levels of translucency and opalescent Impulse shades: IPS e.max® Press High Translucency, Medium Translucency, Low Translucency, High Opacity, Medium Opacity, Low Opacity, Multi, and Impulse.  IPS e.max® CADOn the other hand, IPS e.max® CAD 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. E.max® CAD 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. It has the same translucency shades as e.max® Press, but only has one of the opacity shades: Medium. CAD also has the same Impulse shade. Regarding 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. In addition, more than eight years of clinical use in an independent study by the Clinicians Report® found that milled e.max® has a 95% survival rate. The 5% failure rate was caused by breakdown in cementation, but not in the lithium disilicate material itself. Moreover, this material takes the shape of blue-colored blocks. The blocks undergo a two-step crystallization process, where they arrive at the lab partially crystallized, are milled, then undergo final crystallization. The result is shorter and smaller crystals that are less resistant to fractures and less strong.  Clinical StudiesBoth IPS e.max® Press and CAD have been used in clinical trials for over 10 years with success. A study by K. A. Malament comparing IPS e.max® CAD and Press to other glass-ceramics found the e.max® materials to perform best with a survival rate of 99.75% during a ten-year observation period. Not only that but the e.max® materials were also reported to have surpassed all the clinical practice requirements. The study tested 6000 all-ceramic restorations made of four different materials:
 A study by K. A. Malament Over ten years of clinical studies have found that E.max® Press performed better than conventional materials, such as glass or metal ceramics. It also outperformed its millable counterpart, IPS e.max® CAD in terms of fracture toughness and biaxial flexural strength. E.max® Press offers high levels of safety, survival, toughness, and strength. Six studies focused on a total of 499 restorations over the course of four years documented a survival rate of 98.4% and a fracture rate of 0.4%. Additionally, a 2010 Ivoclar Vivadent® document stated that pressed IPS e.max® has a fracture toughness of 2.75 megapascals (MPa) and a flexural strength of 470-500 MPa. In terms of fatigue, pressed lithium-disilicate monolithic crowns performed better than IPS e.max® CAD as well–especially when treated with a self-etching ceramic primer. As for IPS e.max® CAD, this material has also undergone over 10 years of ongoing quality testing and has proven clinical long-term success and scientifically documented results. Regarding 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.  Wide Range of Applications The wide range of shades also grants flexibility when it comes to applications:
How Can The Dental Lab Help? Dentists throughout Philadelphia and the surrounding region already turn to The Dental Lab for superior quality e.max® crowns and other dental implants to restore their patients’ smiles. Our full-service dental lab offers lithium disilicate restorations through both options of milling and pressing. Contact us today to try IPS e.max®.  Sources: IPS e.max® IPS e.max® - one system for every indication IPS e.max® Lithium Disilicate Tech Sheet How durable are IPS e.max Press and IPS e.max CAD restorations? The Two IPS e.max® Restoration Production Methods CAD-CAM milled versus pressed lithium-disilicate monolithic crowns Clinicians Report November 2018, Volume 11 Issue 11 Keywords:
IPS e.max®, IPS e.max® CAD, IPS e.max® Press, crowns, implants, bridges, restorations, lifelike aesthetics, minimally invasive restorations, lithium disilicate
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