Ive had white film on top of tongue for many years but dentist has never mentioned it(i go every 6 months). does this mean its not leukoplakia?

Tongue: Do you brush your tongue? Do you smoke? Many times a white film is caused by food debris on your tongue and this an be removed y brushing your tongue. Brushing may also improve your breath.

White coating: is caused by food, bacteria and dead-cells. Use a tongue scraper to clean the surface. If it's become painful or persists for longer than a few weeks, see a doctor.