mouth air

When I first started using a Cpap i would have like a air vacume when i opened my mouth. now i can open my mouth and no air escapes at all. i dont know why it does not do that anymore and it makes me wonder if the machine is working right. does anyone know if that is a normal change after using a Cpap for a long time?

Completely normal..you are probably learning to control your tongue. When your tongue touches the roof of your mouth...it stops the air from escaping. It is also somewhat dependent on the mask that you are using.