It seems you are much worried about the yellow colour, the fact is natural colour of teeth is yellow shade. But the sudden change in yellow colour might be due to two reasons, 1. May be due to stains, go for a professional cleaning and follow with brushing twice daily. 2. May be due to faulty tooth brushing or using improper tooth brush ( Rough one) . Please change to soft tooth brush and proper brushing technique. Please visit the dentist and find the exact reason for your problem and proceed with the treatment. Hope this helps you mam

Hot beverages causes stains Have a visit of your dentist for every 6 months Scaling will be done You can also maintain healthy oral hygiene

Brush your teeth twice daily Go for scaling and polishing

If it is due to stains and plaque  can be cleaned  up by professional scaling and polishing. If it is due to excessive brushing for more time with hard brush and applying more pressure which will cause the wearoff of enamel giving yellowish shade due to dentin exposure or thin enamel ..