Maya is back with another case—and this time, the mystery isn’t what you eat… it’s what you don’t replace. When her friend starts having constant bad breath, strange tastes, and even cavities despite brushing every day, nothing seems to make sense. How can someone who brushes regularly still have so many dental problems? Determined to find the truth, Maya begins investigating and uncovers a surprising culprit hiding in plain sight—a worn-out toothbrush. As the clues come together, Maya reveals how using an old toothbrush can lead to bacteria buildup, ineffective cleaning, gum problems, and more. In this eye-opening case, readers will learn why changing your toothbrush is just as important as brushing itself. Because sometimes… the problem isn’t skipping the habit—it’s not updating it.