A hub assembly includes a retainer housing, a retaining member, a biasing element, and an occlusion. The shield is flexible for easy installation over all exposed surfaces of the orthodontic appliance; but is removable after a period of use. The semiconductor device further comprises a lens capping layer on a top surface of the second substrate, wherein the lens capping layer is aligned with the vertical waveguide, and a second optical device over the lens capping layer. The finer pulse may be of shorter duration or of smaller amplitude. The measured points can be relative to the projected plane from the laser.