For bad breath, yellow teeth, sensitivity, and black stains, you may benefit from switching to a toothpaste designed for both sensitivity and stain removal. These help reduce sensitivity while gently removing surface stains. Brush twice daily with a soft-bristled brush, floss regularly, and consider using an antibacterial mouthwash for bad breath. However, black stains often require professional dental cleaning, so visiting a dentist for scaling can give much better and longer-lasting results.