EXTRA Watermelon. EXTRA® Sugarfree Chewing Gum helps to keep teeth clean and healthy, enabling you to feel more confident and ready to make the most of everyday moments and have your Time to Shine™. Make the most of the moment with the clean and fresh mouth feeling of EXTRA® Gum. Wrigley's EXTRA® Watermelon Sugar free Chewing Gum. Endorsed by the FDI World Dental Federation.