Effects of rapid palate expansion on body posture and motor functions in children with monolateral posterior crossbite are test and task-related

Stomatognathic apparatus and the postural system interact through biomechanical chains, whose neuromuscular properties influence both gross and fine motor coordination. To evaluate changes in body posture and motor functions in children with malocclusion who are treated with palatal expanders, 8 right-handed children (6-12 years) with unilateral posterior crossbite were enrolled in this non-randomized pragmatic longitudinal study. Fine motor skills tests, handgrip strength, 3D body posture analysis, electromyography, thermography and stabilometry were performed before and after the treatment with a Rapid Palatal Expander (RPE) at T0pre (before using RPE), t0Post (immediately after using RPE), T1 (after 21 days of RPE use) and T3 (after 6 months). The positive effect on malocclusion, as demonstrated by reduced mandibular offset, did not result in changes in motor symmetries across time. Velocity variance of stabilometry was reduced during the treatment. The immediate wearing of device only slightly affected the results. The beneficial results at the occlusal level through RPE were not accompanied by changes at the neuromuscular and postural level. Clinicians and practitioners should consider that orthodontics treatments and devices which are adapted due to neuromuscular and posturometric tests may be task and test-related.