Plz upload a good quality picture of ur teeth.

Your problem will not go by brushing...it is an intrensic stain not extrinsic U can go fr bleaching...but only after evaluation

The level of fluorosis in the teeth needs to be evaluated by a proper clinical examination or at least a look at the clinical photograph of the affected. Please upload the same for a better opinion. But one thing is for sure---- fluorosis stains are intrinsic in nature and cannot be reduced by tooth brushing and they need camouflage treatments like bleaching or laminates or even metal-free Zirconia crowns if they are bothersome to the patient. Regards.