Ultrasonography in the evaluation of the mid-palatal suture in rapid palatal expansion.

OBJECTIVES: Orthodontists usually evaluate the mid-palatal sutural opening with occlusal radiography. The purpose of this article is to evaluate the sutural opening with ultrasonography (USG) in a series of patients undergoing rapid palatal expansion (RPE). METHODS: The study included 87 USG images and 87 occlusal radiographs from 29 healthy patients (mean age, 13.9 years; range, 11-20 years; boys, 12; girls, 17) who required RPE treatment. The sutural opening was assessed with USG, and the amount of sutural expansion as mesiodistal length was measured immediately after appliance practice (T0), 10 turns (T1) and 20 turns (T2) during the expansion period. Sutural expansion evaluated by occlusal radiographs was scored at every stage. Measurements obtained by USG and scores observed in the occlusal radiographs were compared by non-parametric Kendall's tau test. RESULTS: Both USG and radiographic images revealed normal anatomical structure during pre-expansion (stage T0). On USG, sutural expansion was seen in 19 patients at stage T1. There was no expansion at this stage in ten patients. At stage T2, on USG and radiography, an increase in the amount of expansion was observed in 19 patients with sutural expansion at stage T1 and sutural expansion was observed in 5 patients without sutural expansion at stage T1. No expansion was observed at both stages T1 and T2 in five patients. USG measurements and occlusal scores in both T1 and T2 turns showed statistically significant correlation (p < 0.001). CONCLUSIONS: The results indicate that USG might be a useful method to assess mid-palatal sutural opening in patients undergoing RPE.