Personalized Dentist Or Hygienist Funny Hippo Youth Long Sleeve T-Shirt. Funny dental hygienist or dental assistant Youth Long Sleeve T-Shirt - Black with hippopotamus and Floss Em quote. Also perfect for a dentist or dental office staff. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)