ortho the international C.E. magazine of orthodontics

14 I I C.E. article_ Bent Wire System ducedbythemusclesofthecheekandlips(Quatrelli, Ramirez-Yañez, 2005a) and to change the dimen- sions of the dental arches (Ramirez-Yañez, 2005b). Further research (Yagci 2011) shows that treatment usingtheTrainerproducedapositiveinfluenceonthe masticatory and peri-oral musculature. However, in those cases where more maxillary and mandibular expansion is required to avoid teeth extractions, the Trainer combined with the BWS produces higher amounts of expansion and, therefore, a higher increase in arch perimeter. It is also proposed that by utilizing the Trainer in conjunction with the arch expansion, the force of the tongue activates further alveolar changes that other techniques may not achieve because of the bulk of the appliance being located in the palate where the tongue should naturally position. The BWS is typically composed of a lingual arch, which follows the lingual surfaces of the teeth crowns at the gingival third and ends in a loop at the inter-proximal space between the second premolar and the first molar at both sides. The distal end en- gagesatube(0.7FarrelltubebyMRC)weldedtoace- mentedbandonthefirstmolars(Fig.1).Additionally, the BWS is maintained in place, facing the gingival third of teeth’s crown, by two begg premolar brack- ets cemented on the first premolars with the slot directed toward gingival or by alternately composite stops bonded to the premolar or anterior dentition (Fig. 2). The wire component is 0.7 mm spring wire and is fabricated to the arch form of the starting models either by the laboratory or the orthodontist. ortho2_2012 Fig. 4a Fig. 5 Fig. 4b