White plaque on the tongue is common in people with autoimmune gluten sensitivity (Celiac Disease).
Here's one website:
Geographic Tongue (Glossitis) and its Relationship with Celiac Disease
One of several early mentions of geographic tongue (glossitis) in association with celiac disease may be found in the medical textbook "Coeliac Disease" by ...
Some people have a problem with 'fuzzy tongue'. Some people brush their tongue when they brush their teeth; my Water-Pik comes with a tonge attachment. Some people use mouth washes but there is usually some problem tthat needs attention to stop this. It might be due to an infection in the mouth, under the teeth or in decayed areas. It could be a sign of silent reflux.