Christine,
this (treatment) will seem to go forever. I found it supremely boring but managed to catch up on my sleep.
It looks like you are in the same type of device as I was. I sometimes had problems going down (HBO speak for increased pressure!!!!), similar to what you get when you dive and do not equalize the pressure frequently enough. Surfacing was never an issue, there the pressure equalization happened automatically (bubbling sensation). You could always swallow to effect a pressure equalization.
Basically the problem arises when you have a portion in your body that contains an air space (lung and ear). The lung you equalize by simply breathing and on the ear you may have to work a bit.
(there are other funny thing that may happen with trapped air such as in teeth fillings)
Sometimes they place tubes in you ears to keep the passage (eustachian tubes) open.

re dental work.... I may have to have some and will let you know how that works out.

Best

M