Evaluation of optical density of the midpalatal suture 3 months after surgically assisted rapid maxillary expansion

Abstract

This study evaluated new bone formation at the midpalatal suture after surgically assisted rapid maxillary expansion (SARME) by optical density analysis. The study population consisted of 18 patients, 10 males and 8 females. All patients presented maxillary atresia with posterior crossbite and were submitted to SARME. Maxillary occlusal radiographs were taken at three stages (before SARME, immediately after SARME and after 3 months). Three patients did not attend the session at the 3-month period for achievement of the occlusal radiography and thus were excluded, leading to a final sample of 15 patients. Two regions were selected and analysed at each stage. Region A measured 8 x 1 mm(2) and was located 1.2 cm from the tangent to the maxillary central incisors at the region of the midpalatal suture. Region B measured 5 x 9 mm(2) and was located 4.3 cm from the tangent to the maxillary central incisors at the region of the midpalatal suture. An aluminium scale (step wedge) with eight steps varying from 1 mm to 8 mm was adapted at the end of the films. Radiographs were taken on a Spectro 70X machine (Dabi Atlante, Ribeirão Preto, Brazil) set at 70 kVp and 10 mA with an exposure time of 1.0 s. Radiographs were scanned using a Power Look 1000 scanner (Umax, Taiwan, China) and a computer Dimension E510 (Dell Computer, Taiwan, China). Optical density analysis was performed after digitization of radiographs using the software Image Tool (UTHSCSA, San Antonio, TX). Statistical analysis of region A revealed statistically significant differences between Stages I and II (P=0.0001), Stages II and III (P=0.0001) and Stages I and III (P=0.0003). In region B, statistically significant differences were observed between Stages I and II, I and III and II and III (P=0.0018, P=0.0003 and P=0.0003, respectively). Optical density analysis improves post-treatment control of SARME procedures by surgeons and orthodontists. After 3 months, new bone formation at the midpalatal suture is not complete.