A dental appliance including a concave trough conforming to a plurality of teeth when placed over the plurality of teeth. The concave trough is configured to transition from a first shape to a second shape if a deforming force is applied. The concave trough further includes a shape memory material. The shape memory material is configured to restore the concave trough to an approximate first shape upon an application of an external stimulus. The first shape is configured to apply a first force on a tooth when the trough conforms.