Toughened biaxially oriented polyamide films prepared by dry blending i) a polyamide homopolymer, copolymer, or blends thereof; and ii) a functionalized polyolefin terpolymer comprising maleic anhydride, ethyl acrylate, and an olefin, to thereby form a dry mixture. The method includes a number of launch-cells, a base and an upper attachment arrangement. The shelf rests are in an L-shape in a cross-sectional manner whose angle between the one piece and the other piece is an acute angle. Accordingly, media can be provided to users at a low price or free, thereby minimizing the financial burden on the users. A retaining wire is threaded through this tube and then extend down to attach to the lower mandibular member, which includes two buccal tubes embedded into it to receive the retaining wire.