Abstract
Background: Palatal expansion is one of the most common types of orthodontic treatment, which is administered employing different appliances, and is used for the correction of posterior cross bite. This treatment can elevate the palatal cusp on the maxillary first molar, lead to the rotation of mandible, and increase the height of the lower third of the face. In some cases, the use of bite plane is suggested to avoid vertical dimension changes of the face. This study aimed to assess the effect of removable maxillary expanders on facial vertical dimensions. Methods: In this cross-sectional study, 68 patients referring to Hamedan School of Dentistry and being treated using removable maxillary expander with or without bite plane were examined. Pretreatment and post treatment cephalograms of the patients were analyzed by Dolphin Imaging Software 11.9 version, and the results from 5 cephalometric variables, namely the mandibular plane related to SN line, the angle of mandibular plane related to FH, Y axis, the maxillary plane angulation, as well as the lower facial height were calculated. Patient’s transverse dimension was measured by a caliper on the dental casts along the mesiobuccal cusp of maxillary first molars. Paired t test and independent t-test were adopted for carrying out data analysis. Results: There was no significant difference between the two groups in terms of age and sex at the beginning of treatment. However, maxillary plane angulation and Y axis changed significantly in group with bite plane. (P=0.034, P=0.007). The changes were less than 1.5 degrees. No significant difference was observed between the groups with or without bite plane regarding the changes of cephalometric variables during the treatment. The transverse dimension of the arch was increased significantly in both groups. The changes were similar in two groups. Conclusions: According to the results from this study, the presence of bite plane had no advantage over its absence. However, it seemed necessary to design a randomized clinical trial in this regard.
Highlights
Palatal expansion is one of the most common types of orthodontic treatment, which is administered employing different appliances, and is used for the correction of posterior cross bite
The present study aimed to investigate the effect of using maxillary expansion appliances with or without bite planes on the vertical dimension of the face
A number of 68 patients were examined in this research, of whom 34 patients were with bite plane, and 34 ones were without it (Table 2)
Summary
Palatal expansion is one of the most common types of orthodontic treatment, which is administered employing different appliances, and is used for the correction of posterior cross bite This treatment can elevate the palatal cusp on the maxillary first molar, lead to the rotation of mandible, and increase the height of the lower third of the face. The lateral tipping causes the extrusion of the lingual cusp of the maxillary posterior teeth [5] Both orthopedic and orthodontic movements may cause the mandible to change position by making it rotate in backward and downward directions. With the mandible rotating backward, the angle of the mandibular plane increases during orthodontic treatment [6] These side effects are significant in patients with a long face, large mandibular angulation, and anterior open bite [7]. Providing different mechanisms for expanding the palate, they all work by opening the central maxillary suture [9]
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