My son grinds his teeth when he sleeps and the dentist remarked that he was seeing some wear. Now the dentist could do a custom mold and make a mouthguard (he said) for a few hundred dollars, of which our insurance would pay for like.... NOTHING.

We asked if an over-the-counter guard would work and he shrugged as if to say whatever. So that evening I poked around a bit, read a few reviews, and ended up ordering these.

Update:
We followed the process for molding (basically heat and bite) and tried it out. My son wasn't too keen on it, but he gave it a shot. It wasn't any longer than a few days before he started complaining that his teeth were hurting when he woke and during the day.

He's still young and his jaw is still forming so I can't but think that the mouth guard was putting pressure on them and moving them (like braces).

I got my stefather (a dentist) on the phone, gave him the scoop. He said that at my son's current age, the grinding wear wasn't so big a deal because most of his molars where still baby molars. He suggested we re-look at the issue when his 12 year molars came in. So that's what were doing.