Skeletal and dental changes in the sagittal, vertical, and transverse
dimensions after rapid palatal expansion.
Chung CH, Font B.
The purpose of this study was to examine the maxillary and mandibular
responses to rapid palatal expansion (RPE) in all 3 dimensions.
Twenty children (average age, 11.7 years) who required RPE treatment
were included in this study. Pre- (T1) and post-RPE (T2) lateral
and posteroanterior (PA) cephalograms and study models were taken
for all patients. For each patient, lateral and PA cephalograms
at T1 and T2 were traced, and the sagittal, vertical, and transverse
measurements were made. In addition, on the pre- and postexpansion
models, the widths between the first premolars, the first molars,
and the two acrylic halves of the Haas-type expander were measured.
Results showed that from T1 to T2, the mean SNA increased 0.35
degrees ( P < .05) and ANB increased 1.00 degrees ( P <
.05). Both the ANS and PNS moved downward (1.30 mm and 1.43 mm,
respectively, P < .05), and the mandibular plane angle (MP-SN)
increased 1.72 degrees ( P < .05). The maxillary and mandibular
incisors did not change significantly after RPE. After RPE, the
mean increase of maxillary interpremolar width, maxillary intermolar
width, maxillary width (J-J), nasal width, and interorbital width
were found to be 110.7%, 104.5%, 30.1%, 23.1%, and 3.3% of the
screw expansion, respectively. After RPE treatment in children,
the maxilla displaced slightly forward and downward ( P < .05);
the mandible rotated downward and backward, and the anterior facial
height increased significantly ( P < .05); and the widths of
the maxilla and nasal cavity increased significantly ( P <
.05).
PMID: 15520689 [PubMed - in process]
Am J Orthod Dentofacial Orthop. 2004 Nov;126(5):569-75.
