Half-white and half-yellow teeth are considered to be related to enamel dysplasia, dental calculus, dental fluorosis and other factors, and should be examined in a timely manner in the hospital. 1. Enamel dysplasia: usually due to trauma, malnutrition and other reasons, affecting the development of enamel, resulting in enamel calcification, thus making the teeth half white and half yellow. 2. Dental calculus: usually due to factors such as incomplete oral cleaning and poor dietary habits, resulting in the appearance of calcified material on the surface of the teeth, which is yellow in color, leading to half-white and half-yellow teeth. 3. Dental fluorosis: usually due to high fluoride content in the water, long-term consumption may lead to changes in the texture and color of the teeth, the formation of dental fluorosis, which is generally manifested as half-white and half-yellow teeth. There are many other causes of half-white and half-yellow teeth, and it is recommended to consult a doctor in time to avoid blindly using medication on your own.