Listerine Teeth & Gum Defence Mouthwash Fresh Mint is the ideal, all-round defence for better oral and dental hygiene. Listerine Teeth and Gum Defence is for stronger teeth and healthy gums. No other branded mouthwash offers this unique, four-ingredient formula that penetrates to reduce plaque in depth and help keep your mouth clean and healthy. With flouride for stronger teeth, this mouthwash reduces plaque and even works below the gumline.