Tongue, Dento-alveolar and Speech Changes in Children with Oral Habits

Background: The fixed Bluegrass appliance (BG) has been shown to be an effective habit-breaking appliance in children with finger-sucking habits. A new removable functional appliance, the Myofunctional Trainer (MFT; Myofunctional Research Co.), is now being investigated as an appliance to break oral habits and to achieve favourable dento-alveolar and soft tissue changes. Objectives: A longitudinal pilot study to compare the effects of the experimental MFT and the conventional BG on 1. dento-alveolar relations, 2. on tongue position at rest and during physiologic movement, and 3. on speech, in children with reduced overbite malocclusions associated with oral habits (finger-sucking and tongue-thrusting). Methods: The experimental group (n=4) received the MFT appliance while the control group (n=4) received the BG appliance. Dento-alveolar changes were assessed by cephalometry and study model data using paired t-tests. Longitudinal midsagittal 2-dimensional B-mode ultrasound scans of the tongue surface were performed to determine static and dynamic tongue changes and assessed semi-quantitatively. Speech acceptability scores were rated and analysed using the Wilcoxon's signed rank test. Results: The BG appliance was successful in breaking the finger-sucking habit. The MFT appliance showed only partial success which could be attributed to lack of compliance. At the end of treatment, the open bite was reduced in both groups due to dento-alveolar changes. There was significant variability in static tongue position and movements in response to both appliances. Tongue position changes in response to the BG appliance were variable. In contrast, a favorable elevation in rest position of the tongue was noted in the MFT group. The BG appliance had a short-term deleterious effect on speech acceptability while in place and immediately following removal. However, there were no such effects with the MFT appliance.Conclusions: Ultrasound imaging is a helpful non-invasive tool in assessing tongue position at rest and in function in response to orthodontic interventions.