Federal Circuit Finds Claim Preamble Is Limiting When It Recites Essential Structure Of Invention

In Bicon Inc. v. Straumann Co., 78 USPQ2d 1267 (CA FC 2006), Appellant Diro, Inc. (“Diro”) and Diro’s licensee Bicon, Inc. (“Bicon”) owned U.S. Pat. No, 5,749,731 (“the ‘731’ patent”).  The ‘731 patent is directed towards a plastic cuff that is designed to preserve a space around a dental implant so that when a dental crown is placed on top of the implant, the base of the crown can fit beneath the patient’s gum line.  The preamble of claim 5 of the ‘731 patent reads as follows:

An emergence cuff member for use in preserving the interdental papilla during the procedure of placing an abutment on a root member implanted in the alveolar bone of a patient in which [a] the abutment has a frusto-spherical basal surface portion and [b] a conical surface portion having a selected height extending therefrom comprising …[e] the bore having a taper generally matching that of the conical surface portion of the abutment …(claim elements a-d and f-h omitted for simplicity).

Diro sued the appellee Straumann Company and Institut Straumann AG (collectively, “Straumann”) for patent infringement, alleging that Straumann’s sale of two dental devices infringed at least claim 5 of the ‘731 patent.

The U.S. District Court for the District of Massachusetts granted summary judgment of noninfringement on several grounds.  The court held that claim 5’s preamble was an integral part of the claim and thus limited the claim.  Since Straumann’s devices did not incorporate one of the limitations in the preamble, the court held that Straumann did not infringe the ‘731 patent.  The court also held that Straumann’s devices did not literally or equivalently infringe claim 5 because they did not read on claim element [e].  The court also held that licensee Bicon did not have standing to sue Straumann since Bicon was not an exclusive licensee of Diro, and thus dismissed Bicon as a party plaintiff.

On appeal, the Federal Circuit held that the preamble is regarded as limiting.  Specifically, the Federal Circuit noted that a preamble is considered to be limiting if the preamble recites essential structure that is important to the invention or necessary to give meaning to the claim.  In the ‘731 patent, the preamble of claim 5 is not limited to stating the purpose or intended use of the invention, but contains structural features of the abutment.  Further, the body of the claim referred back to features of the abutment described in the preamble, so that the references to the abutment in the body of the claim derive their antecedent basis from the preamble.  If claim 5 is not limited to the particular abutment described in the preamble, then elements [e] and [h] of claim 5 become meaningless.   As such, the Federal Circuit upheld the District Court’s summary judgment on the issue of no literal infringement. 

Additionally, the Federal Circuit upheld the finding of no infringement under the doctrine of equivalents since claim 5 recites specific convex shapes not found in the accused device.  Quoting SciMed Life Sys., Inc. v. Advanced Cardiovascular Sys., Inc., 242 F.3d 1337, 1346 (Fed. Cir. 2001), the Federal Circuit held that, as in claim 5, “by defining the claim in a way that clearly excluded certain subject matter, the patent implicitly disclaimed the subject matter that was excluded and thereby barred the patentee from asserting infringement under the doctrine of equivalents.”  As such, the Federal Circuit also upheld the District Court’s finding of no infringement under the doctrine of equivalents.   



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