Reasons why we love our Charcoal Bamboo Toothbrushes : they are made of sustainably sourced MOSO bamboo, which is not only an amazing eco-friendly resource, but is also clean on both the micro (BPA-free) and macro (biodegradable) levels.The soft Charcoal bristles help cleaning and whitening your teeth naturally for a healthy smile.The American Dental Association recommends changing your toothbrush every 3 months. Bamboo can change color over time, which is completely normal.