Effects of bonded rapid palatal expansionon the transverse dimensions of the maxilla:A cone-beam computed tomography study

摘要

Introduction: The purpose of this study was to examine the maxillary response on the transverse dimensionsto rapid palatal expansion (RPE) by using cone-beam computed tomography (CBCT). Methods: Twenty-fourchildren (average age, 9,9 years) who had RPE treatment with a bonded expander were included. Pretreat-ment orthodontic records (T1) and immediately after expansion (T2) CBCT images were taken for all patients.For each patient, the width of the nasal cavity at the level of the maxillary first permanent molar and seconddeciduous molar (or second permanent premolar), the width of the maxillary basal bone, and the width ofthe midpalatal suture at the level of the second deciduous molar (or the second permanent premolar), thefirst deciduous molar (or first permanent premolar), and the deciduous canine (or permanent canine) at T1and T2 were measured. In addition, the amount of tipping for both the maxillary right and left first permanentmolars was measured. Results: From T1 to T2, mean increases in nasal width, related to the mean jack-screw opening (8.19 mm), occurred at the levels of the first permanent molars of 33.23% (2.73 mm, P <0.05)and the second deciduous molars of 37.32% (3.06 mm, P <0.05). Significant increases in basal bone of themaxilla were found at all levels (P <0.05), with mean increases of 40.65% (3.33 mm), 44.08% (3.49 mm),46.73% (3.83 mm), and 46.83% (3.62 mm) of the mean jackscrew opening at the levels of the first permanentmolars, and the second deciduous molars, first deciduous molars, and deciduous canines, respectively. Sig-nificant openings in the midpalatal sutures was found at all levels (P <0.05), with mean increases of 52.82%(4.33 mm), 53.23% (4.36 mm), 54.35% (4.46 mm), and 52.77% (4.33 mm) of the jackscrew opening at the lev-els of the first permanent molars, and the second deciduous molars, first deciduous molars, and deciduouscanines, respectively. The right first molar tipped buccally an average of 6.2? (P <0.05), and the left firs...