2. You see signs of plaque and tartar
When foods like carbs and sugars aren’t properly cleaned from your teeth, microscopic plaque germs feed on them and produce an acid, causing tooth decay and gum disease. Plaque is usually colorless. But you can buy plaque-disclosing products like tablets or rinses. These products contain a dye that will harmlessly stain your teeth in areas where plaque has been left behind.
If your teeth are covered in plaque, over time it might lead to tartar build-up, which is a hardened form of plaque and more difficult to remove. If you’re finding plaque or tartar, that’s a fairly clear indication that you need to brush up on your brushing technique.