The Theroux retainer was originally designed by Dr. Kevin L. Theroux DDS, MS. The purpose of this appliance to maintain arch width and tooth position after Phase I treatment while providing sufficient space for erupting adult teeth and exfoliation of the deciduous teeth. It is common for patients in this part of Tx to have short clinical crowns making it difficult to clasp with a retainer making this appliance ideal. This device wraps the incisors and follows 2mm away from the gingival margin while encasing the molars. The rigidity of the material is excellent to maintain the arch form post-expansion.