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May 2009 | Dental Lab Products
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Free zirconia testing

Jay Thomas, Product Manager Ceramics for Tosoh USA explains the company’s business decision to test zirconia components for authenticity.

DLP: Explain if you would some background on Tosoh Corporation Japan as it pertains to the dental industry.

Thomas: Tosoh is the world’s leading supplier of top quality zirconia powder for a number of industries including dental. Manufacturers from many industries buy our powder to make everything from optical fiber connector ferrules to dental zirconia milling blanks. Currently, we have a better than 95% market share for zirconia powder supplied to dental CAD/CAM zirconia milling blank manufacturers worldwide. We also have the world’s largest capacity for this level quality zirconia powder. Our capacity is 1850 metric tons of zirconia powder per year.

DLP: How did Tosoh get such a lock on the dental zirconia market?

Thomas: Tosoh began manufacturing zirconia powder back in the1980s. The quality and consistency of the powder we supply to the world market gives us our high competitive edge. Our zirconia powder manufacturing process is unique. We are able to provide a uniform dispersion of yttria, or stabilizing agent, and other additives throughout the material via our hydrolysis process. Known as the Tosoh process, the uniformity of the dispersed material throughout a milling blank determines the quality of the final sintered product. As best as we can tell, no other zirconia manufacturer uses the same powder production process that we do.

DLP: What happened in the market that caused Tosoh to offer free testing of zirconia components?

Thomas: With the introduction of the open-architecture CAD/CAM systems we’ve seen an increase in the sale of aftermarket CAD/CAM milling blocks. It used to be that the only milling blocks available were those primarily from the European closed systems manufacturers and others whose blocks we knew were being manufactured using Tosoh zirconia powder. But now we have many open systems on the market and, with that, new companies selling zirconia milling blanks whose raw material origins are less clear. Our concern is that zirconia materials of inferior quality may be utilized and if they fail in the mouth, the entire industry as well as zirconia material may suffer as a consequence. For this reason we are offering any dental laboratory worldwide the opportunity to have the zirconia they are using tested by Tosoh, free-of-charge.

DLP: But aren’t there milling blocks on the market that bear the Tosoh logo or claim to be made from medical-grade Tosoh powder?

Thomas: Yes there are, but we could not control unauthorized use of our logo. In terms of the claim of medical-grade zirconia, we sell our powders based on specifications not applications. Based on our market-share, it is clear the dental industry has determined that our powders work best in this application. Don’t get me wrong, we love that companies want to promote the fact that their milling blanks are made with Tosoh powder. We think that’s a great selling point for them. But we’ve politely asked them to cease using our logo and the words “medical grade” in association with the blanks. Wording that we suggest they use in their promotion of their zirconia dental milling blocks is “Produced with Tosoh powder.”

DLP: If you are unknowingly using a non-Tosoh powder manufactured milling block, are there visual clues that the block may have quality issues?

Thomas: Possibly, especially when milling it. It may be more difficult to mill or it may chip easily during the milling process. But like almost anything else, price may be the best indicator. If you buy a batch of milling blanks at below market price, we believe they are probably not made with Tosoh powder.

DLP: So if a laboratory wants their material tested what do they send Tosoh for testing and what can they expect to receive back from Tosoh?

Thomas: Laboratories can submit a milled zirconia coping, bridge framework, implant abutment, even a part of a milling blank if they wish. We will test each sample and provide them our analysis results of the material submitted and our opinion on whether the zirconia they are using was made with Tosoh zirconia powder. However, return of the tested material is not possible.

DLP: So what do our readers need to do if they want to submit material for testing?

Thomas: If they are in the Americas, all they need to do is e-mail info.tusa@tosoh.com; in Europe, e-mail info.tse@tosoh.com; and for other parts of the world, e-mail zirconia@tosoh.co.jp. We will respond to the e-mail providing instructions on where to send the part or component. We then will send the component to our testing facility in Japan where experts will run an analysis of the material. Right now, I can’t promise turn-around time.