# Analysis of Tongue Function from the Orthodontist's Point of View: Not Only a Matter of Deglutition
###### Abstract  
Many studies report that maxillofacial growth is influenced by genetic and environmental elements and that incorrect breathing, chewing, sucking, and swallowing are promoting factors of malocclusion. This study aims to evaluate the function and the influence of the tongue positions in patients with Angle class III malocclusion, maxillary hypoplasia, and posterior crossbite. One hundred patients, aged between 6 and 12 years old, were enrolled for the study. In the first group, patients with a diagnosis of class III malocclusion, affected by maxillary hypoplasia, skeletal class III, and posterior dental positive were recruited. In the control group, not treated patients with no malocclusion, skeletal class I, and without posterior dental crossbite were selected. Regarding atypical deglutition, no statistical differences were reported between the two groups, and 14% of patients reported ankyloglossia. Statistical differences were found in tongue rest position and during the execution of \"hold and pull\" and \"chuck\" exercises. Results obtained in this observational study showed that the clinician (orthodontist or general dentist) should analyze the presence/absence of atypical swallowing, the anatomical and functional aspects, and the tongue behavior in the rest position.  
t o o 2021 11 2  
Swallowing patterns have been linked to environmental factors [11], tongue position and thrust, mouth breathing, and nonnutritive oral habits. The presence of altered swallowing can also be attributed to ankyloglossia, or tongue-tie: a congenital oral anomaly characterized by an abnormally short lingual frenum and which negatively affects the growth and development of the stomatognathic system [12].  
[PERSON] et al. determined that children with an incorrect swallowing pattern may rarely touch the anterior part of the palate with the tip of the tongue [13]. In addition, lingual muscle action is interrelated with mandibular motility and position [14]. Patients with skeletal class III malocclusion have the highest rate of abnormal swallowing, as [PERSON] and [PERSON] in 1994 evaluated by using video-based B-mode ultrasound methods [15].  
Within a dysfunctional swallowing pattern, close attention must be paid to the tongue rest position. Anterior open bite is the predominant type of malocclusion in children aged between 6 and 8 years old [3; 16; 17; 18; 19]. [PERSON] et al. measured the force levels of the tongue against upper incisors and palate during rest position and normal swallowing. They stated that the tongue resting point was a more important contributing factor than the swallowing position in developing dental arch form [20; 21; 22]. Moreover, the results from the cinematic-magnetic resonance imaging analysis described horizontal tongue movement among these individuals and the tendency of placing the tongue between teeth while speaking and swallowing [23].  
When oral dysfunction remains untreated, orofacial myofunctional disorder (OMD) may occur.  
OMD includes dysfunction of the lips, jaw, tongue, and/or orophnx that interferes with the normal growth and the development and functions of the other oral structures. The lack of intervention during the critical periods may result in malocclusion and inadequate facial development [24; 25; 26].  
This study aims to evaluate the function and influence of the tongue positions in patients with Angle class III malocclusion, maxillary hypoplasia, and posterior crossbite.