Aspectos etiológicos da mordida aberta anterior e suas implicações nas funções orofaciais*** Etiological aspects of anterior open bite and its implications to the oral functions

Background: open bite is a complex anomaly that has a difficult treatment. Frequently, unsatisfactory results and relapse of orthodontic treatment are observed. Aim: to associate orofacial malfunction and deleterious oral habits to anterior open bite. To congregate evidences for the better understanding of the etiology and of the development of anterior open bite and its potential association to myofunctional disorders. Method: an exploratory study, to obtain relative risk measurements associating clinical characteristics, sucking habits and myofunctional alterations in 130 scholars. This study was developed in two stages: the first was based on a questionnaire about the child’s oral habits which was answered by the parents, and the second involved odontologic and speech-language evaluations. Results: in this sample, the most prevalent occlusion disorder was anterior open bite, which was associated to vertical facial growth (relative risk (RR) 3.12; confidence internal (CI) 1.20 – 9.90) and to Angle’s Class II malocclusion (p-value = 0.01). An association was also observed for anterior open bite and lingual interference (RR 2.44; CI 1.13-5.27). The same was not observed for speech disorders (RR 0.80; CI 0.20-2.30). Conclusion: a correlation exists between the etiology of anterior open bite, deleterious oral habits, and a few orofacial malfunctions. An association between the history of deleterious habits and the occurrence of lingual interposition during swallowing, as well as with speech disorders was identified. These findings emphasize the necessary interaction between orthodontists and speech-language pathologist during the treatment of patients. The rehabilitation role of speech-language therapy stands out, through the oral myofunctional therapy, emphasizing the positioning of the tongue during swallowing, speech and when in habitual position.