All Ceramic Restorations and the Digital Wave

By David & Marisa Birnbaum, MobileTek Labs
published in the Fall 2009 Ninth District Dental Society Bulletin

In the last couple of years, CAD/CAM restorations have come a long way. The ‘chiclet’ like esthetics of the early years have been replaced with lifelike shading and nice translucencies. The questionable marginal fits and ‘blobby’ anatomy of the past have been corrected thanks to vast improvements in the software and hardware. Even strength and prep issues have been addressed by new stronger materials that can be used for molar crowns with chamfers. These materials innovations offer the opportunity to bond your restorations more regularly.

All of these advances are exciting and we expect that the best is yet to come.

Wading through all of the information out there can be exhausting and confusing. These five focus areas will help you integrate the latest advances into your practice.

1. Strength – Lithium Disilicate porcelain (sold under the brand name EMAX) has a flexural strength of 360 mpa so it can be bonded or cemented into the mouth. As opposed to framework based restorations, the 360 mpa flexural strength is maintained throughout the entire restoration (not just the framework). Thanks to its’ strength and its’ cementability, EMax is indicated for implant restorations.
2. Esthetics – Unfortunately, early CAD/CAM developments focused more on the enabling technology than the esthetics of the completed restorations. Now that the materials have had a few years to catch up, high quality, esthetically pleasing restorations are the norm. Blocks for all materials are available in a wide range of shades and translucencies that can be custom adjusted by skilled technicians with the proper oven, tools, etc. The restorations look good with a quick polish, but they look even better after a bake in the oven. And don’t forget, they are all ceramic so there are no visible metal rims or discolorations.
3. Preps/Fit – Today’s CAD/CAM systems ‘play nice’ with standard all ceramic preps. Milling improvements have eliminated the need to compromise prep design for the sake of the machine. In addition to crowns, CAD/CAM is ideal for preserving tooth structure with onlays, inlays and ¾ crowns. As mentioned, EMAX restorations are compatible with chamfer preps. With all of these options, CAD/CAM preps can expand your arsenal rather than limiting it.
4. Bonding – For optimal strength, bonding is recommended for all ceramic CAD/CAM restorations (EMAX can be cemented when preferable). The adhesive retention provided by bonding your restorations offers more options for your prep designs since mechanical retention is not the primary concern. In addition, ‘same visit’ bonding of restorations immediately seals exposed dentinal tubules and reduces pulpal trauma.
5. Digital Systems – While CAD/CAM restorations make sense for almost all practitioners, in house CAD/CAM systems may not. Full systems cost more than $100K and the learning curve can be steep.

We work with doctors who own their own systems and love them. We also work with many doctors who have looked closely at buying their own machines and have decided to work with us instead.

The concept of digital impressions has wide appeal. Many doctors have told us that they would consider purchasing their own scanner without the milling apparatus. The manufacturers have started going down this route with scanner-only options. We think that this approach will lead to wider adoption but we don’t think 3M will be shutting down their impression material division anytime soon.

The sharing of digital impressions between dentist and lab is another area with great promise. We have worked on some of these cases and the results have been great. More scanners need to be sold for this method to realize its full potential.

So…if Bill Gates’ quote is on target, we won’t see CAD/CAM in every office in 2 years, but we just might see it in the majority of offices within ten years. Right now, this seems like a stretch, but the rate of change in technology is increasing everyday. Will CAD/CAM solve all of the worlds’ problems? Of course not – but…it can be an essential tool in your toolbox.

MobileTek Labs offers their unique CAD/CAM OnSite Lab service throughout the Ninth District geographic area. For more information call David Birnbaum at 917-747-7519 or visit www.MobileTekLabs.com.