I have been using CPAP for 24 years. . I do not use a full face mask. . The small mask that I use has what they call "nasal pillows" which stream the air directly into the nostrils. . There are elastic straps going over the top of my head and around the base of my skull which have Velcro adjustments. . The airflow ramps up to the prescribed value over about half and hour. . I can give you the manufacturer name if you wish.
You still have to get used to the air flow and having warmed air is less troublesome. . The machine has a water reservoir with a heater underneath. I can get you the manufacturer name if you wish. This is only my second machine and I got it about 5 yrs ago. The first machine which I used for 19 years was a real dinosaur of a thing ... probably one of the first on the market and quite noisy/intrusive. . My present machine is orders of magnitude better.
I did try the dental appliance but found it even worse than my dinosaur CPAP machine. . The appliance made and fitted by a sleep-specializing dental practitioner in conjunction with a sleep-specializing psychiatrist, both of whom where "bears" do deal with. . I had to go through a month-long adjustment period ... maybe longer. . Every night or two when first using it, I had to adjust it to bring my lower jaw just microscopically (it seemed) further forward relative to the upper jaw. . During that adjustment period, sleep was far from normal and the discomfort in my mouth was terrible. . And then for 8 or 10 hours the next day, the strained feeling in my jaw muscles lingered. . I hated it and tossed it after 8 months or so ... never got used to it. . It was at least as expensive as purchasing the machine.
With my original dinosaur CPAP I had to get a sleeping pill prescription (Zopiclone 7.5 mg each night) to help overcome the noise distraction and airflow discomfort. . With the new machine, I have been gradually reducing the use of Zopiclone and am now at 3.5 mg.
Tony, I would recommend the machine I have and the nasal pillows instead of full mask (tried several designs, none of which suited the architecture of my face).... just my opinion FWIW.
I can get a full 8 hours sleep, or more, if I want, now ... except for one mid-sleep trip to the loo !