Ora-Clens Oral Hygiene Chews are multi function chews that clean your dog's teeth, prevent plaque and tartar buildup and freshens breath. The advanced formula in these dental chews includes the enzymes Lactoperoxidase and Glucose Oxidase coated on the outside. The dental chews have an abrasive texture, so when dogs chew on these treats, it scrubs the surface of their teeth, effectively removing plaque and tartar build up.