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"Manufacturer matters"

by: Michael Stuart

All dental implant restorations are not created equal. That’s confirmed by a new study from leading materials scientist Professor J. Robert Kelly. His study also confirms Nobel Biocare’s own research regarding the strength of NobelProcera zirconia abutments. Here on our pages, he discusses the research, which has just been published in the International Journal of Oral and Maxillofacial Implants.

Professor J. Robert Kelly

Nobel Biocare News: Your latest research1 tests the fatigue behavior of zirconia implant abutments from four major manufacturers. What led you to take this approach?

Prof. J. Robert Kelly: We wanted to study commercial products, not in order to make commercial comparisons, but to study realistic products. Our goal was to look for processing problems and design issues, so it made sense to see what would happen with products on the market. We selected Straumann Bone Level (BL) implants as our reference and the study received funding from the ITI Foundation. Our search for comparison third-party abutments for the BL implants led us to abutments from NobelProcera and Glidewell – for BL implants these two manufacturers only produce hybrid zirconia abutments that have a titanium insert interface to the implant – and the available abutments from Astra and Straumann that are fully zirconia.

What was your methodology for testing these products?

To set up the method, we first took six of the abutments in each of the four groups and tested them with repeated loads of 200 Newtons. We chose 200 Newtons for the accelerated aging based on our previous work. We didn’t want to break the implants so we thought that was a fair load to start with. The results then allowed us to design phase two, determining the loads that we would use in testing with another 12 implants.

But by the time we got the phase one data, we were astounded. There were clearly significant differences between manufacturers in each of the categories.  This was subsequently verified in full sample testing. 

The NobelProcera product performed outstandingly in this study—is that fair to say? 

Yes, absolutely. While with some of the other abutments we had to reduce the load, with the NobelProcera product we ran-out (no fractures at 25 million cycles), so the load had to keep going higher and higher. 

How would you explain this weakness of the other abutments?

The vast differences were unexpected as the macrodesigns are similar across manufacturers. To help determine why we were seeing such varied results I asked my colleague Dr. Isabelle Denry to do SEM analyses.  Looking at one of the poorest-performing abutments in the study, she identified that the weakness was built in through damage arising from the manufacturing process – subsurface grinding damage, large cracks, inhomogeneous crystals and a diffuse layer of porosity. We clearly see that the manufacturer matters.

There are many reports of issues caused by third-party abutments being used with a system that they were not designed for. As the manufacturer matters, are you an advocate of using only authentic components?

In general, I advise against using lower cost third-party abutments. There’s too much to lose. From what we’ve seen over the years, the quality of the materials is inferior and the outcome has such a high value – the patient has such high expectations of the clinician – why would you risk that to save 100 dollars?

The NobelProcera product performed outstandingly in this study—is that fair to say? 

Nobel Biocare is a high-quality manufacturer. The company manufactures components that are designed, tested and then verified for the BL implant system.

More to explore


Kelly JR, Rungruanganunt P. Fatigue Behavior of Computer-Aided Design/Computer-Assisted Manufacture Ceramic Abutments as a Function of Design and Ceramics Processing. Int J Oral Maxillofac Implants. 2016 May-Jun;31(3):601-9.