Sameer Puri D.D.S. One of the most exciting materials available to CEREC owners is the e.max block. With a compressive strength in the neighborhood of 400 mpa, this porcelain block is two to three times stronger than other available blocks. Clinically it has performed beyond expectations, and recently Ivoclar has published a 10-year retrospective on the studies that have been done on this material. As soon as it’s available from Ivoclar, a digital version will be placed in the download section of this website.
The bottom line on the research is that the material works, and it works well. A summary of the IPS e.max Press system showed a failure rate of 1.6%. (Boning et al., 2006; Etman and Woolford, 2010; Guess et al., 2009; Gehrt et al., 2010; Dental Advisor 2010, and internal Ivoclar study) The studies tracked 499 restorations with a survival rate of 98.6% after a mean observation period of four years. Chipping only occurred in 1.4% of the restorations, and the other failures were due to endodontic failure, caries and fracture. These studies used a combination of adhesive and conventional cementation techniques, which I thought was interesting.
Now us CEREC guys are more interested in milling, so what were the results of the milling studies with e.max CAD? Six clinical studies were reviewed (Richter et al., 2009; Nathanson, 2008; Reich et al., 2010; Fasbinder et al., 2010; Bindl, 2011; Sorensen et al., 2009) with a total of 237 restorations (crowns) that showed that 97.9% of the restorations survived after a mean observation period of 2.5 years. The 2.1% failure rate included chipping, fractures and caries.
So no doubt those of you that have been using e.max in your practices can relate to these results. The material works, and it works well. The blocks have been available in both an HT (high translucency blocks) and an LT block (low translucency). The one shortcoming of the blocks (if there is one) is that esthetically, unless you cut back and layer porcelain, you are dealing with a monolithic material – which means monolithic esthetics. Unlike their Empress Multi counterparts, the blocks are the same shade and translucency throughout.
Until now. At the Midwinter meeting in Chicago next month, Ivoclar is expected to release the e.max Multi blocks graduated shade and graduated translucency from one end of the block to the other. Initially, these blocks will be available for the pressed version only. Once the pressed version is released, we will eventually get our hands on milled versions of these blocks for our milling units. They have not set a release date yet, but I would imagine that it will be after the Chicago meeting for the pressed version, and my hope is that we have milled versions of the e.max Multi blocks by CEREC 27 and a half in the summer.
So all you CEREC owners can salivate at what I expect will become the most popular block for CEREC, giving you the appropriate opacity to block out any dark underlying tooth structure with the appropriate incisal edge translucency for the appropriate esthetics. As more information becomes available on these blocks, we will keep you updated on www.cerecdoctors.com
