Abstract
The aim of this study was to investigate the curative effects of the Muh shield functional orthodontic appliance on anterior crossbite in primary dentition.The subjects were 66 children (mean 5 years 1 month old at start of study) with anterior crossbite who were evaluated regarding the clinical effectiveness of the Muh shield and duration of treatment. Sixteen of the subjects in dental stage IIA also participated in a second study. Model (arch length,arch width, occlusal height) and cephalometric analyses were performed before and after treatments. In addition, change in palate form was evaluated by measuring the vertical section plane area of the palatine.The following results were obtained. 1) Occlusal improvement was found in 78.8% of the subjects for the duration of treatment (average 9.8 months), which was judged to be effective with no differences for duration of treatment between the initiation age and dental stage. 2) Using model analysis,significant changes were found in overjet measurements, length of both the upper and lower dental arches, inter-canine width of both the upper and lower jaws, and occlusal height (p＜0.01). As for inter-canine width, that of the upper jaw was significantly increased, while the lower was decreased (p＜0.01). 3) Cephalometric analysis revealed significant changes for the measurement items ANB,FMA, Y-Axis, and APDI (anteroposterior dysplasia indicator), as well as in U1 to FH and the SN plane angles, and L1 to MP (p＜0.01). 4) A significant increase in the longitudinal section area of the palatine was also found (p＜0.05).In conclusion, the Muh shield functional appliance was found to be effective for treatment of anterior crossbite in younger children. Furthermore, it was found to affect not only the inclination of the anterior teeth, but also the bimaxillary relationship and palatal form even without application of direct orthodontic force to the teeth.
