One of the great things about IPS e.max® CAD is the variety of translucencies that are available to us as clinicians. This allows us to use the material in a number of clinical situations. My general rule is that if there is a lot of good looking tooth structure to work with then using the high translucency block is the best option. It allows me to be much more conservative with my preparation.
The following case study shows how the use of a high translucent IPS e.max CAD block can be used to blend into the existing tooth structure. The patient has mesial caries present on #30 and an existing distal occlusal amalgam. (Figure 1 and 2)
The presence of multiple fractures and erosion warranted cover all of the remaining cusps. That being said the rest of the tooth was in good condition. So why carry the margin of the preparation all the way to the gingiva and reduce the tooth axially. The challenge of course is to hide the margin when it is in the mid facial/buccal region.
Upon excavation of the old amalgam and removal of the caries on the mesial the distal lingual cusp fractured off due to being undermined. (Figure 3) The carious lesion was removed and the lingual fracture was incorporated into the preparation. The facial aspect is beveled with a foot ball diamond to make the transition of ceramic to tooth disappear (Figure 4) The margins are then smoothed and the preparation imaged. (Figure 5)
Once we have the crown out of the mill we try it in and make any adjustments needed. The restoration is then characterized and fired on the Ivoclar Vivadent approved fast firing cycle.
The restoration is then tried in with the clear try in past for Variolink® Esthetic Cement. The esthetics are then evaluated. (Figure 6) Once we have picked the cement shade we want the enamel is etched using the selective etch technique compatible with Adhese® Universal bonding agent. (Figure 7) Adhese Universal bonding agent is then agitated on the preparation for 20 seconds and air thinned. (Figure 8). Variolink Esthetic is then placed on the preparation and the restoration is seated. (Figure 9). The excess cement is removed from the facial and lingual with an instrument or brush. The four corners are tack cured for 2-3 seconds and then the interproximal contacts are flossed. Liquid Strip is then applied to the margin to prevent the oxygen inhibition layer from affect our margins. The restoration is then cured buccal and lingual for 20 seconds.
With the high translucent IPS e.max CAD the margins are able to disappear even when placed in the mid facial region. (Figure 10) This allows for more conservative preparations without compromising the esthetics for the patient.