ST. PAUL, Minn.--(BUSINESS WIRE)--As the next step in its ongoing program to license to the dental industry 3M's patented technologies in various areas of ceramic-based dental restorations, 3M has filed a patent infringement lawsuit in Düsseldorf, Germany. On June 23, 2015, 3M filed a patent infringement lawsuit in Düsseldorf, Germany, against Zirkonzahn Deutschland GmbH located in Neuler, Germany, and Zirkonzahn SRL located in Gais, South Tyrol, Italy. The lawsuit alleges infringement of 3M’s