i have gone through your query.discolration of teeth can be due to various reasons.in your case the antibiotics tetracycline
and doxycycline are known to discolor teeth when given to children whose teeth are still developing (before the age of 8). Mouth rinses
and washes containing chlorhexidine
and cetylpyridinium chloride can also stain teeth.
As you age, the outer layer of enamel on your teeth gets worn away revealing the natural yellow color of dentin.
either from environmental sources (naturally high fluoride levels in water) can also discolor the teeth.
poor oral hygiene
can also lead to yellowness of teeth.
but you dont have to worry.you can go for certain procedures to fix this problem:
Thorough scaling (cleaning) of your teeth.
Avoidance of the foods and beverages that cause stains
Using over-the-counter whitening agents
In-home whitening agents purchased from your dentist
In-office whitening procedures
Hope this ans helps