Patanjali tooth paste not cause discouration of teeth.
In any Tooth paste abrasive is important to clean the teeth effectively but how you are using the Tooth brush is important.
Need to brush only for 2 to 3 minutes.
Should not brush forcefully. It leads abrasion.
Tooth brush bristles matters more than your regular tooth paste.
Next Steps
tooth powder is better than tooth paste.
(reason search in Google)
Health Tips
use smooth bristles tooth brush and brush for 3 minutes 2 times a day but apply light force.