I have sleep apnea related to my lower jaw sliding back when I sleep: PureSleep is the solution for me as it holds my lower jaw in place and eliminates my apnea. I have been using one for more than 10 years. The only reason I give it 4 stars instead of 5 is that, FOR ME, it stops being effective within 3-4 months as it becomes a looser fit by that time, and no longer holds my jaw in place. I only think this would be a problem for people who have really strong tooth-grinding movement. Mine is extreme- where I have broken teeth. But, protecting my teeth is an added benefit to PureSleep: I have not damaged my teeth since I started using it. Instead of my teeth, I wear out the implement. Much better choice. So, overall- this is an excellent device. It stops my apnea (which is due to an underbite, not throat width or other things that can create this issue), and it protects my teeth from damage. It just wears out quickly for me... Highly recommend overall.