Toothbrush Filament-Double Tapered PBT Filament has been tested by authoritative institutions and added some special functions, such as antibacterial function, fluffy effect, etc. By the way, this PBT filament is super recyclable and eco-friendly, and is competitive with regular plastic toothbrush bristles. Toothbrush filaments have competitive features such as good flex recovery, soft toughness, excellent resilience and straightness, which can provide you with gentle and effective oral cleaning care without harming your gums.