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Unasserted or Cancelled Claims May Provide “Probative Evidence” That an Embodiment Is Not Within the Scope of an Asserted Claim

May 06, 2008

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Last Month at the Federal Circuit - June 2008

Judges: Michel (author), Linn, Prost

[Appealed from: N.D. Ill., Judge Kendall]

In PSN Illinois, LLC v. Ivoclar Vivadent, Inc., No. 07-1512 (Fed. Cir. May 6, 2008), the Federal Circuit found that the district court construed the claim term “ready for mounting” of U.S. Patent No. 4,579,530 (“the ’530 patent”) too narrowly. The Court nevertheless affirmed the district court’s grant of SJ of noninfringement, finding that there was no infringement even under the correct construction.

PSN Illinois, LLC (“PSN”) is the assignee of the ’530 patent, originally issued in 1986. A reexamination certificate was issued in July 1989. After reexamination, the ’530 patent contained only one independent claim, which is directed to a method of fabricating a porcelain veneer restoration for a tooth. The method includes “preparing an impression of said tooth,” “forming from said impression a statue of said tooth out of an investment material,” “applying porcelain powder to the surface of said statue to build said veneer restoration,” and “eroding away said statue from said porcelain veneer restoration leaving said restoration ready for mounting on said tooth.” Slip op. at 2 (emphasis added).

PSN sued fourteen defendants, accusing them of infringement of the ’530 patent. It settled with most of them. With the remaining defendants, it settled as to all accused processes other than Ivoclar Vivadent, Inc.’s(“Ivoclar”) IPS Empress technique (“the Empress process”) and processes functionally identical to the Empress process. Ivoclar filed a motion for SJ of noninfringement as to the Empress process. The district court construed the term “readyfor mounting” as “leaving the veneer restoration ready to be fitted to and cemented on a patient’s tooth for which it was custom-made,” and granted Ivoclar’s SJ motion. It concluded that the Empress process could not infringe either literally or under the DOE because the Empress veneer required substantial finishing work after it is removed from the cylinder of investment material and before it is fitted and cemented to the patient’s tooth. PSN moved for reconsideration, but the district court denied that motion. PSN appealed.

On appeal, PSN argued that the district court incorrectly construed the term “ready for mounting” because it excluded all finishing activities. The Federal Circuit agreed. It found that the district court incorrectly focused on the detailed description of the preferred embodiment in excluding subsequent finishing steps in its claim construction, noting that the description in the summary of the invention expressly contemplated performing such finishing steps following removal of the statue. In so finding, the Court noted that its case law did not require all claims to cover all embodiments. Specifically, the Court recognized that disclosed embodiments may be within the scope of other allowed but unasserted claims. Likewise, noted the Court, during prosecution, an applicant may have cancelled pending claims but not amended the specification to delete disclosure relevant only to the cancelled claims. The Court explained that in such cases, unasserted or cancelled claims may provide “probative evidence” that an embodiment is not within the scope of an asserted claim.

Applying these principles to the present case, the Court noted that the description in the summary of the invention and expert witness testimony supported the conclusion that a person of ordinary skill in the art would understand that a veneer was “ready for mounting” after statue removal, even if some “finishing” operations still needed to be performed. Accordingly, it concluded that the district court erred in excluding all finishing steps and should have construed “ready for mounting” as “substantially fabricated such that only final finishing and fitting operations need be performed prior to mounting the veneer on a patient’s tooth for which it was custom-made.” Id. at 11.

The Federal Circuit then turned to the district court’s grant of SJ of noninfringement. It observed that under the correct construction, a veneer must be “substantially fabricated” to be “ready for mounting.” The Court noted that the Empress process required substantial finishing of the veneer prior to mounting it in the patient’s mouth and that as a result, a veneer made by the Empress process was not “ready for mounting” and did not infringe literally. The Court also concluded that the Empress process did not infringe under the DOE because such a finding would read the “ready for mounting” limitation out of the claim. Accordingly, the Court affirmed the district court’s grant of SJ of noninfringement.