The BarkFresh Nano- Bristle toothbrush is made of 100% biodegradable bamboo. With its over 10000 nano bristles, it will gives your dog the best teeth and mouth cleaning experience and is also super gentle on their gums so fear about bleeding gums! The Wavy Bristles thoroughly cleans their teeth and get even gets to those hard to reach places while being extra gentle on their gums. Choose the extra soft toothbrush to not wear down your dog's enamel and don't hurt their teeth no more! We recommend owners to change their toothbrushes once every 3 months! And that goes for you hoomans toothbrushes too!