Rapid maxillary expansion affects the spheno-occipital synchondrosis in youngsters. A study with low-dose computed tomography.
OBJECTIVE
To test the null hypothesis that the spheno-occipital synchondrosis does not show bony displacement in response to rapid maxillary expansion (RME) therapy in youngsters.


METHODS
A total of 16 computed tomography (CT) records were taken from 8 growing patients (2 males and 6 females), before (T0) and after (T1) treatment with RME. All patients had been diagnosed originally with transverse maxillary deficiency. The mean chronological age of the patients was 9.8 +/- 1.8 years (range, 8 to 11.4 years). High-resolution multislice multidetector CT was used to study quantitatively the extent of the opening of the spheno-occipital synchondrosis following RME. A low-dose CT scan protocol was used (80 kV, 10 mA) and the data file of each patient was transferred to a workstation where the anteroposterior width of the spheno-occipital synchondrosis was measured on axial images.


RESULTS
Before treatment with RME (T0), the anteroposterior mean width of the spheno-occipital synchondrosis was 1.73 +/- 0.46 mm immediately after the active phase of expansion (T1), and the width of the synchondrosis increased to 2.30 +/- 0.47. This difference was statistically significant according to the Wilcoxon signed rank test (P < .05).


CONCLUSIONS
Rapid maxillary expansion leads to a small immediate widening of the spheno-occipital synchondrosis in youngsters.
Department of Orthodontics, University of Catania, Catania, Italy. rleonard@unict.it
Rosalia
R
Leonardi
Alice
A
Cutrera
Ersilia
E
Barbato
D002508:Cephalometry / Q000379:methods; D002648:Child; D003393:Cranial Sutures / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008437:Maxilla / Q000002:abnormalities; D009295:Nasal Bone / Q000000981:diagnostic imaging; D009777:Occipital Bone / Q000000981:diagnostic imaging*; D009967:Orthodontic Appliances; D010155:Palatal Expansion Technique / Q000295:instrumentation; D010159:Palate / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011829:Radiation Dosage; D012658:Sella Turcica / Q000000981:diagnostic imaging; D019291:Skull Base / Q000000981:diagnostic imaging; D013100:Sphenoid Bone / Q000000981:diagnostic imaging*; D036542:Tomography, Spiral Computed / Q000379:methods*