Brief orofacial myofunctional therapy and tongue pressure as prediction factors for open bite correction: a randomized clinical trial

Abstract

Objectives: To compare changes in tongue pressure during anterior open bite (AOB) treatment using a fixed palatal crib (PC) alone versus PC combined with brief orofacial myofunctional therapy (OMT), and to determine whether these changes predict overbite correction.

Materials and methods: Thirty-two patients were divided into two groups: the PC group received a fixed palatal crib alone, while the PC-OMT group received PC plus weekly OMT sessions for the first two months. Lateral cephalometric radiographs and tongue pressure measurements using the Iowa Oral Performance Instrument (IOPI) were collected at baseline (T1) and after open bite correction or 12 months later when the appliance was removed (T2). Primary outcomes included changes in tongue pressure and overbite. Analysis of covariance (ANCOVA) controlled for initial open bite severity (p < 0.05). Linear regression analyzed the relationship between tongue pressure changes and overbite correction.

Results: Each group included 16 patients (PC: 3 males, 13 females; mean age 8.65± 0.93 years; PC-OMT: 9 males, 7 females; mean age 7.97 ± 1.00 years). Both groups showed similar overbite improvements. Tongue pressure increased in all variables across groups; however, swallowing pressure increased significantly less in the PC-OMT group. Changes in tongue pressure were not associated with overbite correction.

Conclusions: Treatment with PC alone or combined with brief OMT yielded comparable overbite corrections. The addition of OMT moderated tongue pressure increases during swallowing. Changes in tongue pressure did not predict open bite correction in mixed dentition.

Clinical relevance: Brief OMT combined with PC may reduce atypical swallowing post-crib removal, supporting long-term treatment stability.

Keywords: Dentition, mixed; Myofunctional therapy; Open bite; Orthodontics.