GDLD started 2018 with a significant appellate victory for a dental manufacturer who faced down a California class action brought against it under the state’s Unfair Competition Law (UCL). Richard M. Barnes and Linda S. Woolf led the trial team that prevailed in a three-week bench trial in San Francisco Superior Court. Plaintiffs had claimed that the Class II prescription medical device at issue concealed a biofilm “hazard” that purchasing dentists did not appreciate. On appeal, they claimed that the trial judge misapplied the UCL and the law of the case on express warranty by considering the purchasers’ long-standing knowledge of how to treat biofilm in any dental device that uses water. Derek M. Stikeleather briefed and argued the matter in the California Court of Appeal. He persuaded the panel that the trial judge had substantial evidence that the highly sophisticated licensed purchasers knew of the claimed defect. This disproved the plaintiffs’ allegations of fraud under the UCL and breach of an express warranty for certain uses. The precedential decision has been designated for publication.