Microstructures and nanostructures consisting of a substrate, an array of pillars capped by metallic disc, metallic dots disposed on the sidewalls of the pillars, and a metallic backplane that can interact to enhance a local electric field, the absorption of the light, and the radiation of the light are disclosed. The heat sink is made by die-casting, and includes a chassis and a plurality of fins extending upwardly from the chassis. , caused by andor associated with intervertebral disc degeneration, and methods of treatment of a spinal disorder andor spinal pain. One or more retractors can be placed into the gingival crevice as needed given the particular tooth and procedure involved. The compartments communicate with each other via a channel that is closed by an excess pressure vent device allowing gas at excess pressure to pass in one direction only from the smaller volume compartment to the larger volume compartment.