Electropalatographic and cephalometric assessment of myofunctional therapy in open-bite subjects.

Myofunctional therapy (MFT) is often prescribed to correct tongue-thrust swallowing, with the expectation that anterior open bite (AOB) will reduce spontaneously if a more posterior tongue posture is learned. However, MFT has not been subjected to systematic evaluation. Electropalatography (EPG), which is used in speech pathology to measure dynamic tongue function for diagnostic, therapeutic and research purposes, is a suitable technique for the evaluation of MFT. This prospective clinical study assessed the effect of tongue re-education therapy on tongue function and dento-facial form in AOB patients. Electropalatography recordings of speech and swallowing, and lateral head cephalometric radiographs were obtained from eight 10-year-old boys with tongue-thrust swallowing behavior and AOB before and after a course of tongue re-education therapy. Although differences in cephalometric measurements before and after therapy were small, there was some evidence of a trend for upper and lower incisor eruption, with concomitant reduction of the AOB. Analysis of the EPG speech data was inconclusive, but the swallowing data showed trends for more consistent and more anterior patterns of EPG contact after therapy. Comparison of pre- and post-therapy EPG data with data from a parallel study using a group of age-matched controls indicated that some "normalisation" of swallowing behaviour had occurred. The results of this research imply that the therapy was partially successful in improving tongue function during swallowing and in reducing AOB. Further research on a larger sample over a longer observation period is required for more accurate assessment of soft and hard tissue changes.