IP Law Daily Dispute over patented dental implant drilling method remanded for further chewing by PTAB
News
Tuesday, June 19, 2018

Dispute over patented dental implant drilling method remanded for further chewing by PTAB

By Peter Reap, J.D., LL.M.

The Patent Trial and Appeal Board correctly determined that claims 1-8 of a patent for a method for drilling holes for dental implants, held by Sirona Dental Systems GmbH, were unpatentable as obvious in light of prior art, the U.S. Court of Appeals for the Federal Circuit has ruled. Further, the petitioners, Institut Straumann AG and Dental Wings Inc., failed to demonstrate that claims 9-10 of the challenged patent were unpatentable, as the Board correctly found. However, the Board erred when it denied Sirona’s contingent motion to amend the claims of its patent, and that ruling of the Board was vacated, and the dispute remanded with instructions to the Board to reconsider in light of recent precedent (Sirona Dental Systems GmbH v. Institut Straumann AG, June 19, 2018, Moore, K.).

Sirona’s U.S. Patent No. 6,319,006 "relates to a method for producing a drill assistance device," i.e., a drill template, "to precisely place a pilot hole for a tooth implant, wherein the pilot hole for the tooth implant is aligned relative to the teeth that still remain in the jaw." The petitioners sought inter partes review of claims 1–10 of the ’006 patent. After institution, Sirona filed a contingent motion to amend the claims pursuant to 37 C.F.R. § 42.121, which the Board denied. The Board held claims 1–8 of the ’006 patent as unpatentable as obvious over the combination of German Patent No. 195 10 294 (Bannuscher) and U.S. Patent No. 5,842,858 (Truppe). Sirona appealed the determination that claims 1–8 are unpatentable and the denial of its contingent motion to amend. The petitioners cross-appealed the determination that claims 9–10 are patentable.

Sirona’s appeal. Sirona appealed the Board’s obviousness determination regarding claims 1–8 based on the combination of Bannuscher and Truppe. The parties filed different translations of Bannuscher, a German reference, the court noted. It describes a method of determining an optimal position for a dental implant based on 3-D model geometry of the mouth or jaw region and an X-ray image of the same and producing a surgical template with this optimal position to use in implant surgery.

The different translations both described digitally inputting plaster models cast from impressions taken of the "patient’s oral situation" into a computer, but did so differently. According to the petitioners’ translation, the plaster models are transferred into a skull-based simulator in a 3-D relationship "using a recording sheet." According to Sirona’s translation, the plaster models are transferred "into a skull-referenced simulation device with the aid of a recording bow." Based on these different translations, the parties disputed whether Bannuscher digitally inputs structures of the mouth or movements of the jaw into the simulation.

Sirona did not challenge the Board’s legal analysis but questioned on appeal whether substantial evidence supports the Board’s findings that the combination of Bannuscher and Truppe discloses "carrying out a three-dimensional optical measuring of the visible surfaces of the jaw and of the teeth and compiling a corresponding measured data record" based on the Board’s construction, and whether a person of ordinary skill in the art would have been motivated to combine the references.

Specifically, the Board found that "Bannuscher discloses digitally inputting the X-ray image and 3-D model geometry of a patient’s jaw and teeth into a computer for ‘correlating’ the data sets." It found that Bannuscher does not disclose carrying out a 3-D optical measuring of the visible surfaces of a patient’s jaw and teeth but found that Truppe did, "using light from a conventional video camera, with reference to a three-dimensional coordinate system provided by the relative positions of the magnetic sensors." It found that a person of ordinary skill in the art would have been motivated to use Truppe’s optical measurement system to generate 3-D surface data of the jaw and teeth for use in Bannuscher’s planning simulation software to assist in determining the optimal implant position.

Sirona argued that Bannuscher never indicates that data reflecting the topography of the plaster models is input into a computer and the petitioners never identified an instrument in Bannuscher that could do so. Substantial evidence, however, supported the Board’s finding that such data is input, the court reasoned. The Board determined that whether Bannuscher uses a recording bow to measure jaw movement is not dispositive in light of Bannuscher’s other disclosures. Bannuscher discloses that "a three-dimensional model geometry of the mouth or jaw region and an X-ray image thereof are input digitally, relative to the patient’s skull, into a computer." The 3-D model geometry refers to the plaster model of the mouth or jaw region, which represents the visible surfaces of the jaw and teeth. Based on this disclosure, substantial evidence supported the Board’s finding that Bannuscher digitally inputs the structures from the plaster model for correlation and not simply jaw movement.

Substantial evidence also supported the Board’s finding that Truppe discloses "carrying out a three-dimensional optical measuring of the visible surfaces of the jaw and teeth," as claimed, the court decided. Sirona did not dispute that Truppe discloses an optical measuring of the visible surfaces of the jaw and teeth. Instead, it argued that Truppe’s camera measures only in 2-D and that Truppe uses electromagnetic sensors to determine the relative positions of the jaw in 3-D. The appellate court disagreed. Truppe uses an optical camera along with 3-D sensors and a device for positional determination to create a 3-D optical representation that can be inserted into the 3-D X-ray image in a positionally-correct manner. The Board’s construction required no more than that, the court said.

Substantial evidence also supported the Board’s finding that a person of ordinary skill in the art would have been motivated to combine Bannuscher and Truppe. Relying on the petitioners’ expert, the Board found that both Truppe and Bannuscher disclose a similar process of correlating 3-D X-ray and visible imaging data of the jaw and teeth to generate the best representation of a patient’s jaw and teeth. This evidence was enough to support the Board’s finding of a motivation to combine. Therefore, the Board’s conclusion that claims 1–8 would have been obvious over the combination of Bannuscher and Truppe was affirmed.

Sirona also challenged the Board’s final written decision by arguing that the Board relied on theories that first appeared in the final written decision. An inter partes review must proceed "in accordance with or in conformance to the petition." SAS Inst., Inc. v. Iancu, 138 S. Ct. 1348, 1356 (2018). Thus, it would thus not be proper for the Board to deviate from the grounds in the petition and raise its own obviousness theory, the court observed.

However, the Board did not deviate from the grounds in the petition by relying upon the geometry data and citing for support the same portions of Bannuscher that the petition cited, the court concluded. The Board simply used the term "geometry data" to refer to the digitized plaster models that were expressly cited in the petition. Because the petition provided Sirona notice and opportunity to address the portions of Bannuscher relied on by the Board, the Board’s reliance on these portions of Bannuscher did not violate the Administrative Procedure Act (APA) and was not inconsistent with SAS.

The Board, however, erred when it denied Sirona’s contingent motion to amend, the Federal Circuit determined. The petitioner bears the burden of proving that proposed amended claims are unpatentable. Aqua Prods., Inc. v. Matal, 872 F.3d 1290, 1324–25 (Fed. Cir. 2017) (en banc) (plurality opinion). The final written decision, which issued prior to the Federal Circuit’s en banc decision in Aqua Products, improperly placed the burden on Sirona to demonstrate that the proposed substitute claims were patentable. Thus, the Board’s denial of Sirona’s contingent motion to amend was vacated and the case remanded for the Board to reconsider in light of Aqua Products. The Board shall determine in the first instance, in light of recent precedent including SAS, whether it may consider combinations of references not argued by the petitioner in opposing the motion to amend claims, and, if so, what procedures consistent with the APA are required to do so.

Petitioners’ cross-appeal. The Board concluded that the petitioners did not demonstrate that claims 9 and 10 were unpatentable over Bannuscher and Truppe and that Bannuscher did not satisfy the "drill assistance device" limitation of claims 9–10. Substantial evidence supported these findings, the court held.

The petitioners argued that the Board should have applied findings from its analysis of Sirona’s contingent motion to amend to its analysis of claims 9–10. In essence, the petitioners were attempting to add references to the ground of unpatentability put forth in their petition, the court observed. There was no error in the Board’s decision not to decide grounds of unpatentability not raised in the petition. Thus, the Board’s determination regarding claims 9–10 was affirmed.

This case is Nos. 17-1341 and 17-1403.

Attorneys: Justin J. Oliver (Fitzpatrick, Cella, Harper & Scinto) for Sirona Dental Systems GmbH. Wesley Otto Mueller (Leydig, Voit & Mayer, Ltd.) for Institut Straumann AG and Dental Wings Inc.

Companies: Sirona Dental Systems GmbH; Institut Straumann AG; Dental Wings Inc.

MainStory: TopStory Patent FedCirNews

Back to Top

Interested in submitting an article?

Submit your information to us today!

Learn More