I have mild apnea, about 12 hypopneas an hour untreated. I use the TAP (Thornton Adjustable Positioner) dental device, and I now have fewer than 5 hypopneas an hour.
However, I must sleep on my side even with the TAP in place. If I sleep on my back, I go back to 12 hypopneas an hour.
The TAP has been a godsend for me. My sleep is much better now.
It must be fitted by a dentist although the patient can adjust it at home. There's a key you use to extend the jaw forward.
It takes a lot of patience because you must get your jaw used to the protrusion very slowly. I've advanced mine to the point where my upper and lower teeth meet when I'm wearing the device.
As far as a pillow goes, I love the Therapuetica. I learned of it from a couple of chiropractors.
It is quite firm, and for side sleeping it keeps your neck in just the right alignment.
Memory foam is great, but you sink into it gradually, thus losing alignment during the night.
The Therapuetica comes in different sizes. You measure from the base of your neck to the edge of your shoulder.
Petite is the proper size for me. That surprised me because I am tall and always fancied I had broad shoulders. I guess I'm not quite the bruiser I thought I was (har).
It takes a while to get used to the Therapuetica, especially if you have been using memory foam. You don't gradually sink into the Therapuetica. It remains firm, so your neck remains in correct alignment throughout the night.
I got mine from Amazon. You can look up reviews there. It's really helped with my neck pain.