A dental appliance is disclosed designed to protect a wearer's dentitions against injury from impacts suffered in sports or other activities that can cause chipping, fracturing, dislodging or evulsion of teeth. The appliance may be custom-fittable with at least one pocket having an energy absorbing fluid. The energy absorbing fluid be nanosuspensions of small particles in viscous fluids that can undergo shear thickening when the dental appliance is struck by an object. The appliance dampens and diffuses horizontal and axial forces and directs them away from dentitions thereby reducing the risk for dental injuries.