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The aim of this prospective randomized clinical study was to cephalometrically investigate the dentoalveolar and soft tissue changes produced by a removable appliance with a palatal crib associated with high-pull chin cup therapy in children with an Angle Class I anterior open bite (AOB) malocclusion. Thirty children (8 males and 22 females) with an initial mean age of 8.3 years and a mean AOB of 4.1 mm were treated with a removable appliance composed of a palatal crib associated with chin cup therapy for 12 months. A control group of 30 individuals (7 males and 23 females) closely matched for age, initial mean age 8.6 years, gender, and ethnicity with a mean AOB of 4.6 mm was followed without treatment. The measurements (means and standard deviations) were statistically analysed using a paired t-test. The results showed no significant differences in the level of molar eruption or in lower anterior face height, suggesting that the vertical control expected from the chin cup therapy did not occur. Dentoalveolar changes at the anterior region were evident, with statistically significant extrusion, retrusion, and lingual tipping of the maxillary and mandibular incisors (P < or = 0.05). However, these hard tissue changes did not imply soft tissue changes and the variables related to the soft profile were not statistically significantly different between the groups. The dentoalveolar changes at the anterior region of the dental arches were mainly responsible for closure of the AOB in patients treated in the mixed dentition.

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ObjectiveThe aim of this prospective study was to compare the dentoalveolar effects produced by two types of palatal crib, removable (Rpc+C) and fixed (Fpc+C), combined with chincup in growing patients with anterior open bite.Material and MethodsEach group comprised 30 patients, in the mixed dentition phase, with similar cephalometric characteristics and skeletal ages. Group 1 (Rpc+C) presented initial mean age of 8.3 years and mean anterior open bite of 4.0 mm. Group 2 (Fpc+C) presented initial mean age of 8.54 years and mean anterior open bite of 4.3 mm. The evaluation period comprised 12 months between initial (T1) and second lateral radiograph (T2). The T2-T1 changes were compared cephalometrically in the 2 groups using the non-paired t-test.ResultsVertical changes in the posterior dentoalveolar region were similar between the groups (about 1 mm) and no significant differences were found in molar mesialization. The Fpc+C group had in average 1.6 mm more improvement of the overbite as a result of greater maxillary incisor extrusion (1.3 mm). Patients in this group also presented less lingual tipping of maxillary incisors and more mandibular incisors uprighting. ConclusionsThe Fpc+C combination was more efficient in the correction of the negative overbite mainly due to greater extrusion of the maxillary incisors. However, the Rpc+C appliance promoted better upper and lower incisor inclination, resulting in a more adequate overjet.