Sameer Puri Do you know the emax Impulse blocks? These are interesting blocks made by Ivoclar. On first glance they appear to be the same as the emax blocks that you normally use to restore teeth with inlays, onlays, crowns and veneers. However the Impulse blocks, while they share the same physical characteristics as regular emax blocks, are intended to be used for a very special purpose.
The Impulse blocks come in two variations. The Opal blocks and the Value blocks. The strength of these blocks is the same as regular emax HT and LT - roughly 360-400 mpa of strength. The milling time is essentially the same. You can mill them fast, the lithium disillicate material has the same physical and chemical characteristics as regular emax. If then there are so many similarities, what then is the difference between these and the regular emax blocks? First of all the Opal blocks are intended to be used only for minimal prep veneers, essentially enamel replacement. The Opal blocks come in two shades, Opal 1 and Opal 2, with Opal 2 being a bit more opaque. Essentially if you are doing multiple teeth with minimal prep veneers and you want to increase the value of the teeth, you would use the Opal shades. Remember, enamel replacement only. If you end up doing a full coverage crown for example, you will have an extremely white and monochromatic look. The second block in the Impulse family are the Value blocks. Value 1, Value 2 and Value 3 are the shades. These blocks can be used in more routine indications. While the HT blocks are translucent and the LT blocks are bit more opaque, the Value blocks are a combination of the two. With the Value block, you can take a discolored stump and block out the darkness and still retain some life in the restoration. If you use an LT for example in a situation where there is a dark stump, the opacity of the LT tends to make the restoration appear lifeless and dead. The Value blocks have the ability to block out the stump and maintain some translucency thereby preserving the life of the restoration. Now you know the indications, why are these blocks so infrequently used? Essentially its due to the fact that Opal blocks have a limited indication (enamel replacement) and more importantly, both the Opal and Value blocks require a long firing cycle. Essentially a 35 minute firing cycle. This means that you cannot use the fast fire 14:50 firing cycle with these blocks. This in essence means that most clinicians won't even consider these blocks for chairside use. Regardless, in the proper clinical situation, you can find that these blocks will come in handy to get that right shade on a patient.
