How exactly does a “Night Guard” (Occlusal Splint) used in the treatment of teeth grinding work, and are soft splints harmful?

A night guard is a transparent, rigid acrylic appliance, custom-made in a laboratory based on millimeter-precise measurements taken by a dentist, and usually fitted onto your upper teeth. The purpose of a night guard is not to completely eliminate teeth grinding; its main function is to distribute the immense force exerted by your chewing muscles evenly across all your teeth, preventing wear and tear and breakage, and to protect the jaw joint by absorbing the destructive pressure (acting as a shock absorber). A crucial medical warning is necessary: ​​soft silicone guards, readily available online or in pharmacies, that dissolve in hot water and fit into the mouth are completely harmful to bruxism sufferers. Soft material creates a chewing gum-like effect in the mouth, further stimulating the brain’s chewing center and causing the patient to grind their teeth much more intensely and vigorously at night; a night guard must be made of rigid material and manufactured by a dentist.