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District court's claim construction too narrow, but noninfringement finding affirmed anyway
May 07, 2008

In a decision yesterday, the Federal Circuit held that a district court construed a claim limitation too narrowly. However, even under the broader construction, summary judgment was still appropriate, because there was no genuine issue of fact that the accused method still did not practice that element, either literally or under the doctrine of equivalents.

PSN Illinois (PSN) owns a patent relating to a method of fabricating porcelain veneers for teeth. After reexamination, the patent had one independent claim, reproduced below (emphasis added):

1. A method of fabricating a custom-made porcelain veneer restoration for a tooth without the use of a metal matrix comprising the steps of:
a. preparing an impression of said tooth;
b. forming from said impression a statue of said tooth out of an investment material;
c. applying porcelain powder to the surface of said statue to build said veneer restoration conforming to the shape of the bonding surface of said tooth;
d. firing the porcelain veneer restoration on said statue; and
e. eroding away said statue from said porcelain veneer restoration leaving said restoration ready for mounting on said tooth.

The accused process is a "lost wax" process. It begins by taking an impression of the tooth, making a stone model of the impression, and placing wax on the model in the desired shape of the veneer, producing a structure called a "wax-up." Sprues (wax posts) are then attached to the wax-up, and the wax-up is placed in a cylinder. The cylinder is then filled with an investment material and heated so the wax and sprues melt, leaving a void in the shape of the veneer, as well as a channel to the void where the sprue was. Porcelain is then heated and pressed through the channel formed by the sprue to form the veneer. The investment cylinder is then eroded, leaving the veneer attached to a porcelain sprue. The sprue is then removed, and various finishing work is done before mounting it on the patient's tooth.

The district court construed the term "ready for mounting" as requiring that at the end of the process, the veneer be in its final form, i.e., no additional "finishing" be performed before mounting on the tooth takes place. Specifically, the court construction was "leaving the veneer restoration ready to be fitted to and cemented on a patient's tooth for which it was custom-made." Under this construction, the court held that summary judgment of noninfringement was appropriate, as in the accused process additional work must be done before the veneer is ready, including removing the sprue. PSN appealed.

The Federal Circuit held that the district court's construction was too narrow. The specification indicated that a veneer could be "ready for mounting" even if additional finishing activities were to be performed before actual mounting takes place. PSN argued that a recent case, Oatey Co. v. IPS Corp., supported its broader construction. There, the Federal Circuit held that "where claims can reasonably [be] interpreted to include a specific embodiment, it is incorrect to construe the claims to exclude that embodiment, absent probative evidence to the contrary." The court found this reliance unpersuasive, noting this statement does not require every claim to cover all disclosed embodiments. Here, the fact that some claims were cancelled during reexamination provided evidence that all emobidments were no longer within the scope of the claims. Further, the preferred embodiment was included in the proper construction.

The narrowing during reexamination notwithstanding, the summary of the invention and expert testimony supported a construction that a veneer could be "ready for mounting" even if additional finishing steps need to be performed.

Unfortunately for PSN, this did not result in reversal of the district court's summary judgment of noninfringement. The Federal Circuit held that, even under this broader construction, there could still be no infringement. This is because of the nature of the accused process, and specifically because of the presence of the porcelain sprue after the process is completed. In order to be "ready for mounting," the veneer must be "substantially fabricated," and its color and shape must be defined. In the accused process, however, the presence of the sprue prevents the veneer's shape from being defined after the investment material is eroded. PSN's expert testimony that removal of the sprue was a "finishing" step was discounted as conclusory. As a result, the accused process does not literally infringe the claims. Further, the court held there could be no infringement under the doctrine of equivalents, because it would vitiate the "ready for mounting" limitation.

Chief Judge Michel, who authored the opinion, also showed he has a sense of humor. From page 9:

When read in context of the claim language and the specification, we find that the district court was incorrect in holding that the description of a preferred embodiment had more bite than the description in the summary of the invention.

From page 11:

PSN argues that the operations performed following removal of the investment material in the accused Empress process are merely finishing steps and thus the veneer of the Empress process is “ready for mounting” after the investment material is eroded. This argument is hollow, however, and we affirm the district court’s summary judgment of noninfringement.

From footnote 3:

We note that PSN's suggestion that all steps which remove porcelain are finishing steps could be taken to ridiculous extremes. Under this rationale, sculpting the veneer from a square block of porcelain could be characterized as "removing porcelain"; yet an unformed block of porcelain would clearly not be "ready for mounting." Indeed, Gutzon Borglum might have considered removing a burr from George Washington's nose at Mount Rushmore as final finishing, but we doubt he would have thought blasting the presidents' heads from unformed stone was finishing just because both processes involved "removing granite."

It's enjoyable when the court lightens up their opinions a bit.

To read the full decision in PSN Ill., Inc. v. Ivoclar Vivadent, Inc., click here.

The Chicago IP Litigation Blog has coverage of the district court phase of this case here.

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