Case Study: Chairside CAD/CAM Implant Abutments in the Anterior Region

Thursday, May 8, 2014

Case Study: Chairside CAD/CAM Implant Abutments

After rumors flying about its release for the past several years, we finally have Ivoclar Vivadent’s e.max CAD material available for use with implant abutments.

I do appreciate the amount of research and development that went into making this material work for implants. The last thing we need as an industry, much less Ivoclar itself, would be to throw some new material into patients’ mouths without a clear understanding for how it will perform.

At the time of writing, you can only use the material in conjunction with Sirona’s TiBase system, a titanium pre-fab cylinder abutment that has compatible restorative connections with many of the more popular implant systems. Below, you can see an example of how the system telescopes together, in this case using a zirconia abutment rather than one milled from e.max.

Tibase

So why the hype about this new CAD/CAM block?

  1. Esthetics – Nothing looks worse than a gray, cylindrical pre-fab abutment trying to fill the space of a non-cylindrical tooth. Think of an orange on a toothpick. The e.max material allows you to create a UCLA type or custom abutment that is shaped and shaded like dentin. It allows you to use a more translucent material over the abutment, or place your margin supragingival in the case of a shallow implant placement.
  2. TiBase Cylinder – The material is supported internally by a titanium cylinder. This means better strength, as well as a metal-to-metal implant connection. Once you have to dig out the leftover fractured zirconia from the inside of an implant, you will get the benefit of the TiBase system.
  3. In-Office Fabrication – With the expansion of CAD/CAM dentistry, the ultimate trump card is the ability to fabricate this in the office. With e.max you don’t need an expensive sintering furnace like you would for zirconia. You may not do this as a same-day crown, but there is nothing wrong with delivering the next morning either.

Below is a case involving implants at teeth position 8 and 9, as well as a porcelain crown at tooth number 7. The patient had previously fractured both central incisors due to trauma, as well as the incisal edge and entire lingual surface of number 7. The teeth were extracted with immediate placement of the implants with provisional crowns. This helped to control any resorption and maintain the shape of the socket.

A traditional impression was taken using Impregum impression material for ease of fabrication. We actually could have used a set of Scanposts from Sirona and done the entire case with no model, but this implant case was completed using a physical impression. TiBase cylinders were placed on the lab analogs, and then scanned into the CEREC software.

The CEREC software allows you to first design a full contour version of the tooth. You can visualize the screw hole for the abutment, and if it is in a non-esthetic area, fabricate a full contour crown similar to a UCLA abutment. In this case, the screw hole would have extended out the incisal edge, so a cemented restoration was chosen to provide the most esthetic outcome.

Once the full contour tooth is designed, the software splits the tooth into two files—one for the abutment and one for the overlying crown. You can control the placement of the margin of the final crown in this step.

Once final edits are done to ensure proper thickness and contours, you can proceed to mill the two separate pieces.

The abutment and crowns are fired to crystallize the e.max material.

Because the two pieces were from the same file, they fit together perfectly.

The abutments were attached to the TiBase using Ivoclar’s Multilink Abutment resin cement. Final finishing was done using the stone model.

Note that due to some recession in the central papilla, the central contact was lengthened to avoid a black triangle effect. The provisionals were removed, and we had excellent tissue contours for to try in the final crowns.

The abutments were torqued down, and crowns on tooth numbers 7, 8 and 9 were cemented using Scotchbond Universal and RelyX Ultimate.

The case will be reviewed in a few months’ time. Using High Translucency e.max CAD blocks resulted in a bit more translucency than the surrounding teeth, and I think I could have potentially achieved an even better result using the lower translucency blocks.

Questions or comments on the case? Do you have an interesting case to share as well? Drop a note below or contact our editor at [email protected].

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