ABSTRACT
Objective: To study the effects of the palatal spur and chincup in the early treatment of anterior open bite in patients with Angle class Ⅰ malocclusion. Methods: Electronic search was conducted to find studies about the effects of the palatal spur and chincup in the early treatment of anterior open bite in patients with Angle class Ⅰ malocclusion. Data extraction and risk of bias assessment of included studies were conducted. RevMan5. 3 software was used fore Meta-analysis. Results: 6 clinical trials were qualified to the Meta-analysis. Compared to the control group, there was no significant change of skeletal measurments after treatment (P＞ 0. 05), and no significant change in dental measurments in chincup group (P＞ 0. 05) . While overbite, U1-PP (mm) and L1-MP (mm) were increased (P ＜ 0. 05), U1-NA (°) and L1-NB (°) decreased (P ＜ 0. 05) in the 3 groups of fixed palatal crib, bonded spur associated with the chincup and the removable palatal spur associated with the chincup. Conclusion: Chincup is not effective in the early treatment of the anterior open bite in patients with Angle class I malocclusion. But chincup combined with palatal spur or crib and have a positive effect on the closure of open bite through the palatal clination and extraction of the anterior teeth without influence of molar intrusion and skeletal change.
ABSTRACT
Although it is well known that the chincup, used to correct a skeletal class III malocclusion in growing children, reduce the mandibular prognathism by arresting the growth of the mandibular length and rotating the mandible posteroinferiorly, the majority of the studies about chincup is focused on condylar head that plays an important role in mandibular growth. The aim of this study was to evaluate the morphologic change of the mandibular symphysis where extraoral force is applied directly during chincup treatment. The data for this study were obtained from lateral cephalometric radiographs of 62 growing children(chincup group:32, control group:30) with mixed dentition who had been accepted for the orthodontic treatment at Chonbuk National University Dental Hospital. The results were as follows : 1. Symphysis height was increased both in chincup therapy group and control group during treatment. Symphysis depth was decreased or maintained the initial values in chin cup therapy group, whereas increased in control group. Posterior symphysis depth was decreased both in chin cup therapy group and control group, but anterior symphysis depth was increased in control group, whereas decreased in chincup therapy group. 2. Chin depth and chin curvature were increased in control group, whereas maintained or decreased in chincup therapy group during treatment. Chin angle, menton angle and symphysis angle were decreased in control group, whereas increased in chincup therapy group. It suggested that bone deposition in pogonion area that occur normally with mandibular growth was suppressed by direct contact of chincup. 3. When growing children wear chincup, symphysis morphology was maintained due to inhibition of forward growth at mandibular symphysis. It may be due to the suppression of bone deposition in anterior part of symphysis.