While decay does not develop on porcelain crowns and other dental crowns , you need to make sure your crowned teeth are properly cared for, including regular brushing and flossing. This care is the same as the care you apply to your normal teeth. If you do not apply proper dental hygiene, there may still be caries and tooth decay under porcelain or other type of crowns. Especially if you regularly consume things like coffee and red wine, which tend to leave stains on natural teeth, you should remember that your crowns may be stained. Teeth whitening products do not work in crowns, so if you want to whiten your crowned teeth, you will need to discuss this with your dentist and possibly replace or update your crown with white tooth caps.