Hard night guards should be chosen for patients with heavy to severe grinding. It’s made from acrylic; a clear, hard plastic that is heat cured for maximum strength and are rigid with absolutely no flexibility. Hard night guards aid in protecting teeth as well as other vital structures by creating a protective barrier between upper and lower teeth. The overall thickness of a night guard is about 2.5mm and it can be easily repaired or added to if you need to adjust the vertical.