Home > News Updated 06 December 2016 Heath24 Health Challenge: Week 21 It's time for our weekly health challenge! Find out if you can score a perfect 10 on our quiz. 0 Joshua Carstens NEXT ON HEALTH24X Sugar tax too low to work 2017-03-30 10:23 More: News advertisement Other news Diet and nutrition Sugar tax too low to work Medical QUIZ: 10 facts and myths about asthma Lifestyle High-tech acne treatments Medical What does the ADHD brain look like? Medical Could grinding your teeth cause headaches? Medical 7 alternative remedies for erectile dysfunction From our sponsors How to care for your vaginal flora Live healthier Hello? » SEE: Interesting facts about hearing loss Earworms: Let it go Is it bad to sleep with earplugs all the time? SEE: Do women hear better than men? The reason why men often appear not to be listening could be because they actually can't hear you. Confident smile? » Acidic drinks can harm your kids' smiles The facts on bleaching your teeth Am I taking good care of my teeth? Why are my teeth stained? We know the rules – brush your teeth twice a day and floss to keep them healthy. But, have you ever wondered what causes those stains that sometimes appear?