OraVet Dental Hygiene Chews contain a special ingredient, delmopinol. Delmopinol works to form a preventive barrier that blocks bacteria and the future formation of plaque and calculus (tartar) that builds up over time. OraVet Chews are the first and only dental hygiene product for dogs that contain delmopinol. The dual-action approach of OraVet Chews doesn’t just clean teeth and freshen breath. It creates a barrier to protect against plaque, calculus and bad breath.