Recurrence pattern: every year on the day after Thanksgiving.

National Flossing Day is observed worldwide every year on the day after Thanksgiving. Established in 2000 by the National Flossing Council, this holiday emphasizes the importance of dental hygiene, particularly after the abundant meals typical of Thanksgiving. The day serves as a reminder to floss, as up to 40% of tooth surfaces are interdental and cannot be cleaned with a toothbrush alone. The origins of dental floss date back to the early 19th century, with the first patent issued to Johnson & Johnson in 1898. Flossing helps remove up to 80% of plaque from between teeth and below the gums, preventing bad breath, gum inflammation, and tooth decay. People celebrate by learning about dental floss history, pledging to improve their dental hygiene, and sharing information on social media using the hashtag #NationalFlossingDay.