Home > News Updated 26 October 2016 Health24 Health Challenge: Week 15 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 ADHD: A timeline 10 minutes ago More: News advertisement Read Health24’s Comments Policy Comment on this story 0 comments Add your comment Thank you, your comment has been submitted. Logout Comment 0 characters remaining Share on Facebook Logout Comment 0 characters remaining Share on Facebook Loading comments... Other news Medical ADHD: A timeline Medical SEE: 5 ways to avoid backache during pregnancy Parenting WATCH: Fighting for inclusive education for children with Down syndrome News First NGO-owned nursing surgery unit opens in Khayelitsha Medical A third of asthma patients may be misdiagnosed Lifestyle Neglected rural pets pose scabies risk for humans 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?