Dear practo user Can share X-ray.

See Change of tooth could be Due to Trauma..She might not be aware because trauma doesnot mean necessarily an accident or injury..it could be even because of opening the bottle cap with a jerk or some previous history of fall or sometimes if she is having some abrasion / erosion or caries or decay till the pulp in the adjacent teeth..retrograde infection can also take place..

Change in the color of the tooth is mostly because of trauma to the tooth!! If you the colour changes in future too,she might need a RCT followed by a crown!

Change in color in the font tooth is most often due to a history of fall or other kind of trauma to that tooth. Kindly attach a picture of the related tooth It can be a case of pulpal necrosis or internal resorption which might require root canal treatment.

Please consult your dentist at the earliest

Normally change in color of tooth is due to trauma or any accidental injury to tooth. Tell her to visit her dentist as soon as possible.

A picture would be very useful , but the best  treatment plan  can be made when you visit the  dental clinic .

Pl attach a picture of the area in question

Normally change in colour is due to trauma.Injury can be of various forms. It can occur while eating also. You have to visit your nearest dentist to get an xray done. Only then the further treatment plan be decided.

It's called calcification of teeth if it's from inside , usually trauma for long-term from below teeth e.g. teeth grinding can cause this if this is the case simple veneer can be done for aesthetic purposes. If outside minimal scaling procedure can solve the issue.