Mealey's (July 30, 2019, 2:48 PM EDT) -- MINNEAPOLIS — A federal magistrate judge in Minnesota on July 25 ruled that lead plaintiffs in a securities class action lawsuit against a dental supply company and certain of its former executive officers failed to sufficiently show that a majority of the defendants violated provisions of federal securities law in alleging that they conspired with competitors to fix dental supply prices and boycott group purchasing options (GPOs) (Plymouth County Retirement System v. Patterson Companies Inc., et al., No. 18-871, D. Minn., 2019 U.S. Dist. LEXIS 124014)....