By now everyone is well aware of the successes of IPS e.max, which has proven to deliver strong, esthetic restorations in all areas of the mouth. In fact, long-time prosthodontist Dr. Kenneth Malament, a world-renowned researcher and educator on all ceramics, says his choice is Ivoclar Vivadent's ceramic for all of his single unit restorations. But where this material really has a unique spot is in the posterior areas.

Today, a number of clinicians are using zirconia in the posterior, but Dr. Malament, DDS, M.Sc.D., believes IPS e.max is still the best option for posterior single units, the bread and butter cases for many dentists. While many patients and clinicians are moving away from PFMs, they should be aware that while zirconia is an option that provides significant strength, lithium disilicate delivers the best survival data, economics and better esthetics, according to Dr. Malament.

"e.max is the best we have ever worked with," said Dr. Malament, who has had a prosthodontics practice in Boston since 1977.

The material and science advances that helped bring about a product like IPS e.max may very well lead to a changing of the guard for those clinicians who had grown accustomed to the traditional porcelain fused to metal (PMF) restorations.

According to Ivoclar Vivadent's IPS e.max Scientific Report Vol. 02 (2001-2013), which is available online at: ivoclarvivadent.us/emax/science, more than 75 million IPS e.max restorations have been delivered, and the crown survival rate is 98.2%. Dr. Malament's results have been even more impressive.

Originally, Dr. Malament and his colleagues extensively used and studied Ivoclar Vivadent's Empress with tremendous results. Since switching to IPS e.max, his success numbers have been staggering.

"I have researched all ceramic materials 32 years and have a database where every all ceramic restoration I have ever done is studied with 29 different confounding variables," said Dr. Malament, who practices with Dr. Dan Nathanson, Professor, Chairman Restorative Sciences, Boston University School of Graduate Dentistry, and Dr. Hans Peter Weber, Professor, Chairman Restorative Sciences, Tufts University School of Dental Medicine. "Of all the of the materials we have ever studied, Empress, all the time, was the best from the point of years of survival. I have cemented up to today, 2,133 Empress restorations over 265 months with 103 failures. A failure is a fractured crown that requires replacement. A chipped restoration is also studied in the database and of the 31 chipped Empress restorations all were easily smoothed and did not need to be replaced."

Now that he uses IPS e.max, the success rate is significantly higher than those impressive Empress figures.

"As of today, and at 85-86 months (7 years) 546 patients, 1,896 units and I have but one failure," he said. "We've never seen this performance in a ceramic material before ever."

These are the types of numbers that keep scientists up at night. Dr. Malament and his research colleagues are more than impressed by the data they have accumulated and the science on IPS e.max.

"The one failure has been studied extensively. We were totally obsessed with how this happened and needed to understand the fracture mechanics of the event," he said. "The lone 'failure' was a patient who was a severe bruxer who after four years fractured the lithium disilicate."

Dr. Malament has confidence that IPS e.max restorations will not only look great, but last long, keep his patients happy and his practice thriving.

"Obviously we have done a significant summer of anterior and posterior crowns. IPS e.max restorations are etch able when cemented, providing me with great confidence. This is not always the case with other materials," he said. "It has been a extraordinary material. I've never seen a material behave this way. Never, never, never.

Dr. Malament, who also uses IPS e.max regularly for minimally invasive inlays and inlays, and says the material has helped his practice profits grow dramatically, but just as important is the confidence it brings in knowing that the restoration will not have to be redone.

"I look at everything from the point of view of cost effectiveness," Dr. Malament said. "The IPS e.max lithium disilicate has been the most unusual material I have ever ever worked with. It's been an amazing material."

He adds that Ivoclar Vivadent is a company that listens to clinicians and responds. He also noted that they have material advances planned in the near future that are designed to deliver an even more esthetic ceramic.

"They (Ivoclar Vivadent) have been the most responsive manufacturers in prosthotontics," he said. "They're just a very responsible company to us."

Conclusion 

"I do not see the rationale for doing anything but IPS e.max anywhere in the mouth," Dr. Malament said. "For two reasons academically for me. Number one, lithium disilicate wears almost exactly like natural tooth. Zirconia if it's polished does very well but if it's rough, and as dentists we often have to adjust occlusions...once it's rough and not polished perfectly, its abrasive. Now, I'm not saying that matters...look, we've all worked our whole careers in metal ceramics. However, you can't compare any material we have in the posterior to lithium disilicate.

"Secondly, I can't see one advantage it has over the lithium disilicate in a single unit situation, and there is no comparison to it in terms of esthetic results. Zirconia is so smooth internally and has been reported to often come off teeth after cementation. Since e.max is etch able and can be cemented with either glass ionomer resin or resin cements I have not experienced a crown coming off."

Another factor about IPS e.max is the ceramic stratification and layering that can enhance the esthetic results.

"Our research team headed by Dianne Rekow and Van Thompson and just confirmed by Dr. Rober Kelly's group at University of Connecticut proved that if you add the fluorapetite veneering ceramic at 0.5 mm. The bi-layered restoration is stronger than the virgin monolithic. That to me is unbelievable.

"Dentistry is a hard business. Our overhead is high. We have great staffs, but they're expensive. You have to know that the work you do is going to have 1. Value and 2. It's going to survive so you don't have to remake it. And lose money. There has never been a story like this in dentistry yet."

Esthetics and strength: While IPS e.max is the "go to" material of choice for anterior esthetics, it has a proven track record for performance in the posterior region of the mouth as well.