Soft Charcoal bristles Bentodent Eco Brush Bamboo Toothbrush (Charcoal) Soft has an ergonomically round bottom and super soft bristles. The handle is made from organically grown, sustainable, biodegradable, and antimicrobial bamboo. Bentodent Eco Brush charcoal bristles are, arguably the best quality and most trusted bristle available. Bentodent Eco Brush Bamboo Toothbrush (Charcoal) toothbrushes are "Dentist approved, Mother Nature recommended".