White tongue is often related to oral hygiene. Your tongue can turn white when the tiny bumps (papillae) that line it swell up and become inflamed.
Bacteria, fungi, dirt, food, and dead cells can all get trapped between the enlarged papillae. This collected debris is what turns your tongue white.
Some of the conditions can cause white tongue:
poor brushing and flossing
dry mouth
breathing through your mouth
dehydration
irritation, such as from sharp edges on your teeth or dental instruments
fever
the cause of the white tongue needs to be determined and the treatment to be started accordingly. Some cases resolve on their own and other need conservative treatment
Next Steps
consult a physician