The causes of yellow non-smoking teeth include enamel loss, stain deposition, plaque, and dental hypoplasia. 1. enamel loss: due to severe wear and tear of the teeth, there is enamel loss, exposing the dark yellow dentin. 2. Color stains deposition: For example, if you drink tea or coffee, there will be pigmentation on your teeth, which will lead to yellowish teeth. 3. Plaque: If you don’t clean your teeth on time or don’t brush your teeth correctly, food debris, soft dirt, etc. will adhere to the surface of your teeth and form plaque, which will lead to a change in the color of your teeth. 4. Dysplasia: Dysplasia can cause defects on the surface of the teeth, which can lead to the accumulation of plaque. If there are symptoms of yellow non-smoking teeth, which affects the aesthetics, you can seek the help of a professional dentist, and you should have regular dental checkups to avoid adverse effects.