Hello,
For whitening and yellowish ness of your teeth I.would.recommend a cleaning session with a near by periodontist/ dentist.
If still.not satisfied you can go for teeth whitening procedure.
Next Steps
visit the dentist.
for teeth sensitivity use vantej toothpaste by dr.reddy's.
for teeth whitening use- glister toothpaste or any toothpaste which has activated charcoal in it.
Health Tips
if teeth are sensitive better not to do whitening procedure as it may exaggerate the sensitivity.