The aim of this study was to observe the effects of treatment with a Trainer T4K® myofunc tional appliance of thirteen late mixed dentition patients. We conducted thorough clinical examinations that included assessment of breathing and swallowing capabilities and took profile cephalograms and study models for each one. We also selected a control group that had been treated only with palatal expansion so that we could distinguish the effects of myofunctional therapy from those of expansion. We observed significant mandibular growth (p<0.05) of 3.24 mm on the average and a significant decrease in overjet, essentially linked to dento-alveolar effects, in the Trainer T4K® group. Swallowing and breathing function also improved in these patients. The two groups had similar maxillary and mandibular expansion.

So we conclude that use of a Trainer T4K® myofunctional appliance results in improved antero-postero dental relationships and an improvement in oral functioning.