Dentists asks patients to wear a night-guard when there is a suspicion of night-time teeth-grinding, causing significant wear of tooth enamel. From a paleo perspective, re-calcification of teeth thanks to a healthy diet should help with this issue some, but would wearing a night-guard prevent, or degrade, the body's ability to re-calcify teeth?
It seems that putting a device directly over your teeth for seven+ hours a night would somehow prevent re-calcification from working properly (though perhaps I simply misunderstand how re-calcification works).