Well, you need to know that your teeth turns yellow due to a number of reasons and forms a greyish shade due to food stain. However, one of the major factors that contribute to teeth turning yellow is heavy cigarette smoking. Nicotine leaves yellowish or a brown layered stain on the surface of your teeth and this can be removed by undergoing a tooth cleansing. Some people believe that chewing teeth whitening gum or mouth fresheners will protect your teeth, but you may end up inviting more health problems if used in excess. https://zobuz.com/steel-bite-pro-customer-reviews-any-side-effects-must-read/5909/