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Dental-Impression Patent “Loses Its Bite”

October 25, 2002

Decision icon Decision

Last Month at the Federal Circuit - November 2002

Judges: Lourie (author), Newman, and Friedman

In All Dental Prodx, LLC v. Advantage Dental Products, Inc., No. 02-1107 (Fed. Cir. Oct. 25, 2002), the Federal Circuit reversedin- part and affirmed-in-part a SJ that U.S. Patent No. 5,213,498 (“the ‘498 patent”) was invalid and not infringed. The Federal Circuit found that the ‘498 patent was not invalid, but agreed that the accused product does not infringe.

Advantage Dental Products, Inc. (“Advantage”) owns the ‘498 patent, which is directed to a method for making custom dental impressions using a material known as polycaprolactone. Typically, dentists use a dental-impression tray filled with alginet to make a mold of a patient’s teeth for a dental appliance, such as a crown or cap. Instead of using a tray or container, the ‘498 patent discloses heating polycaprolactone until it is pliable and then placing it directly over the patient’s teeth. The polycaprolactone then cools into a rigid mold. The claims of the ‘498 patent set forth a step of heating an “original unidentified mass” of material to make a mold.

All Dental Prodx, LLC et al. (collectively “All Dental”) sells a product known as “TEMP TABS TRUE BLUE,” which is a flat, oval-shaped tablet also made of polycaprolactone. The tablet is heated until pliable and then molded directly over a patient’s teeth. All Dental brought suit seeking a DJ that the ‘498 patent was invalid and not infringed by its tablet.

The district court found that the phrase “original unidentified mass” was not described in the ‘498 patent such that one skilled in the art could understand the bounds of the claims, and, thus, the claims were invalid under 35 U.S.C. § 112, ¶¶ 1 and 2. In addition, after reviewing the prosecution history, the district court construed “original unidentified mass” to mean “a mass that does not have a specific preformed size and shape.” Since All Dental’s tablet has a specific preformed size and shape, the district court held that it did not infringe the claims of the ‘498 patent.

With regard to invalidity, the Federal Circuit found that although the ‘498 patent was not a model of clarity, the specification was reasonably clear enough to provide a context for understanding the meaning of “original unidentified mass.” The Federal Circuit noted that the specification of a patent need not describe the claimed subject matter in exactly the same terms as used in the claims and the specification’s failure to exactly mention a claimed limitation is not fatal.

Furthermore, the Federal Circuit noted that the prosecution history was clearly relevant as intrinsic evidence for determining validity. The Federal Circuit agreed with the district court that the prosecution history clarified “unidentified original mass” to mean a mass that does not have a specific preformed size and shape. Since the district court was able to construe the phrase, the Federal Circuit held that the district court was incorrect in concluding that this phrase was indefinite. Therefore, the Federal Circuit held that the ‘498 patent was not invalid.

With regard to infringement, the Federal Circuit agreed that All Dental’s tablet had a preformed shape and, thus, did not infringe the claims of the ‘498 patent.