I have long had a problem with mouth breathing, or so I thought. For a long time I used a chinstrap (homemade), and it helps, but for the past year or so I have been experiencing dry mouth even though the chin strap is working well and leaks are normal. In fact, when I wake up in the middle of the night my mouth is dry, but my mouth is completely closed.
It seems to me that the problem is not mouth breathing but, rather, inadequate flow of saliva.
I have a (possibly) related problem with tears. My tear ducts don't work properly. Allergies bring on tears, but the tears do not drain from the eyes. All day long I am constantly daubing tears out of my eyes.
I don't know if the problem with tears is related to waking up with a dry mouth. Ducts for tears and saliva work a lot the same. They both involve fluid movement, so there may be a connection.
Any ideas or suggestions?