Dr. Kourosh Maddahi, a cosmetic dentist in Beverly Hills, spent decades recommending mouthwash products to patients who were advised not to brush for one week after certain procedures. He found that producers of those products would change their formulas or disappear altogether, so in 2015, he developed his own. Before long, Dr. Maddahi’s all-natural, certified non-toxic, and microbiome-safe mouthwash took off, along with toothpaste and sensitivity-free whitening strips.