I agree with Madiesmom. Why not offer your puppy some meat with bone-in (like raw chicken quarters) or chew toys like bully sticks to clean her teeth instead of something artificial with loads of chemicals. Do you know what the biggest ingredient in Oxyfresh is? Hehe, it's deionized water (aqua).
Here's the whole ingredients list: Deionized Water (Aqua), Oxygene® (Stabilized Chlorine Dioxide), Zinc Acetate, Sodium Citrate, Chlorophyllin-Copper Complex, Sodium Benzoate, Sodium Hydroxide, Citric Acid
Sorry, I wouldn't let my pets near this stuff.