What should I do if the space between my teeth turns black?

The blackening between teeth should be treated according to the specific underlying cause: 1. **Pigmentation**: Long-term smoking, drinking tea, coffee consumption, or eating deeply pigmented foods may lead to pigment deposition between teeth. It is recommended to improve oral hygiene by using tools such as dental floss and interdental brushes to clean between teeth. Additionally, ultrasonic teeth cleaning may help remove accumulated pigments. 2. **Dental calculus**: If the black substance between teeth is dental calculus, it is usually caused by poor oral hygiene leading to calcification of dental plaque. Self-removal is difficult, and professional dental cleaning using ultrasonic scaling should be sought promptly. 3. **Dental caries**: Tooth decay is another common cause of blackening between teeth. Early-stage caries may appear as yellowish-brown or black spots. If left untreated, these may progress into cavities. Treatment options for dental caries include fillings or root canal therapy, depending on the severity of the decay. It is recommended to seek timely dental consultation to identify the exact cause and receive appropriate treatment under professional guidance.