The Full Zirconia Hat Trick--Can a Material Evolution Lead the Way for a Three-Way Win/ Patient, Doctor, and Lab?

by Brad Guyton, DDS, and Veeraraghavan V. Sundar, DDS

The problem: Gold is expensive. Even if you don’t follow the gold market, you know this is an issue because of your high lab bills the past few years. Over the past 12 months, gold has hovered around $1,600 an ounce. The rapid acceleration of PPO plans over the past decade (PPO dental plans are now approaching 70% of all new insurance plans sold), and the decrease in reimbursement to the dentist (a handful of states have already decreased their reimbursement rates for their provider dentists), coupled with the high cost of cast gold crowns and PFMs has placed unprecedented pressure on dentists to produce high quality restorations at a reasonable cost. When you accept a PPO that pays $650 for a crown for a patient who is tough on teeth, and a full contour gold crown is $325, the math just doesn’t add up. What are you to do?

The hat trick solution:

A hat trick is defined as a positive feat that happens three times during a game, or when other achievements occur in threes. Is zirconia the answer that may help us fill the void when gold may not be an option? With all the options out there, how do we best communicate a solution to patients, providing them with adequate informed consent while not overloading them with confusing information?

With choices often comes confusion

Your patients count on you to know what’s in their best interest and to present them with your recommendation. It’s increasingly important to have great communication skills when discussing the options that exist for your patients when it comes to crowns and veneers.

Prep and delivery — Why zirconia fills a void

Zirconia has enjoyed significant success since it was introduced for clinical use over a decade ago as the high-strength, high-toughness ceramic alternative to metal-based restorations. The inherent biocompatibility and durability of transformation-toughened yttria-stabilized zirconia has made it an attractive alternative for practitioners who want enhanced esthetics and better managed practice costs.

Fig. 2 — Wear Comparison of Porcelain, Zirconia, and Enamel

Research is necessary to ensure porcelain compatibility with this innovative substructure material. While some studies have highlighted chipping and fracture of porcelain at low levels on this material, most of these issues appear to be technique-related rather than material-related.

Manufacturers have responded to this issue with not only training and education, but also with material improvements. The recent introduction of monolithic zirconia with enhanced translucency, such as Cercon ht from Dentsply Prosthetics, BruxZir from Glidewell Dental Lab, and Lava Plus from 3M ESPE, has enabled us to create and place CAD/CAM zirconia restorations that are efficiently milled, but only stained and glazed (as opposed to veneered with ceramic). This innovation significantly reduces the technique sensitivity of veneering, as well as enhances lab efficiency through computer-aided manufacturing.

Since these materials typically display excellent strength (~1200MPa), and are similar in composition to the previous generation of zirconias, the study suggests we can expect the same durability. Without the veneering porcelain layer, and with 30% to 40% enhanced translucency, a very conservative preparation is possible (often <1 mm for axial and occlusal reduction). With staining and glazing, the crowns are tooth colored and offer enhanced esthetics, especially in the posterior. It is also possible to veneer these materials for esthetic anterior-posterior combination cases.

A final concern with this type of strength is what effect does wear have on the opposing dentition? We now have access to research that compares the wear of a next generation zirconia (Cercon ht) to a conventional zirconia (LAVA) as well as PFM and zirconia porcelains. The test results indicated that zirconia ceramics yielded superior wear behavior and lower antagonistic wear compared to other porcelains. In addition, while adjusting zirconia increased the wear slightly, repolishing significantly lowered the wear of the antagonist.

Clinicians now have a material that offers an esthetic alternative to metal crowns for patients that are tough on teeth. In addition, when adjustments are necessary, repolishing with medium and fine diamonds mitigates the wear factor to levels better than those obtained with porcelain. All in all, the use of zirconia materials that offer a depth of clinical and scientific evaluations to support their claims provides an excellent practice alternative.

Prep and delivery — Case presentation and communicating options to patients

With Zirconia now in your treatment armamentarium, you have an opportunity to 1) inform and motivate your team about the option, 2) educate your patients about the option so they trust your expertise and recommendation, and 3) enhance your profit and/or pass savings on to your patients. We suggest you consider all three.

References available upon request.

Brad Guyton, DDS, MBA, MPH, is COO for Jameson Management, and Veeraraghavan V. Sundar, PhD, is Global Program Manager for the Prosthetics Division at DENTSPLY International. Dr. Guyton and the Jameson team of 40 clinical, management and marketing advisors improve the lives of dental professionals through in-office and online coaching, speaking, and management services. DENTSPLY manufactures and distributes professional, high quality dental product solutions in 120 countries under well known industry brand names. Learn more at www.JamesonManagement.com or www.Dentsply.com. Reach Dr. Guyton at [email protected] or Dr. Sundar at [email protected].