If a nightguard makes my molars intrude, what should i do about grinding my teeth when i sleep? i don't want my front teeth absorbing all of the bite

See a dentist: There are many different type of nightguards available out there. Sounds like you have one that only covers the anterior teeth which could cause extrusion of the posterior teeth. In most cases it is not a major problem but if you feel like yours causing an issue than see your dentist and discus your concerns. Maybe you need one that covers all of your teeth. Hope that helps

See DDS: Speak to the dentist about the difference types of noghtguards available. More important, what a nightguard does is simply separate the teeth, so you do not grind, it is made of plastic and needs to be replaced on an as needed basis. Get to the etiology of the problem and not just treat the symptoms. Do you also have TMJ involvement? Have the DDS check all.