I bought a Z-Quiet oral appliance (as seen on TV) and shared it with my Sleep Center Physician. He said to give it a try. We were traveling in Africa in tented camps without electrical power and did not have many options. It worked reasonable well. I also used an ear loop surgical mask that helped to retain the humidity in my nasal passages. Fortunately we were in humid environments.
A custom dental appliance ($800+) would certainly perform better, but my $50 option was adequate under the circumstances.