This randomized controlled study was conducted on a total sample of thirty young adult orthodontic patients (20 girls and 10 boys) according to sample power analysis of previous study of Araneda et al (10) using G-power.
The inclusion criteria of patients who have transverse maxillary deficiency and an age ranged from 11–18 with mean of 14.20Y, 15.13Y, 15.40Y in group 1,2 and 3 respectively, no pathology affect the MS, good general health, so, any medical records who met the inclusion criteria were analyzed.
The exclusion criteria, history of trauma, syndromes affecting midface and previous orthognathic or orthodontic treatment.
Screening of patients was done in outpatient clinic, Orthodontic department, Faculty of Dental Medicine, Al-Azhar University, Cairo, Boys branch. It was approved with the ethical committee at the same Faculty under code number 775/220.
The study followed the requirements of the Consolidated Standards of Reporting Trials (CONSORT) (Fig. 1). Thirty young adult orthodontic patients were selected, classified and randomly allocated into three equal groups, according to the type of the expansion appliance, using online generated randomization plan (Graph Pad) found at the website
http://www.graphpad.com/quickcalcs/index.cfm .
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Group (1): The conventional hyrax. (3 males-7females) (Fig. 2a).
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Group (2): The Hybrid hyrax. (4 males-6females) (Fig. 2b).
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Group (3): The MSE expander (3 males-7females) (Fig. 2c).
The interpretation of research project was performed verbally and in writing and the objectives of the study were discussed with the patients and parents and a consent form for participation in the research project was obtained before any procedure.
Four-banded Hyrax expanders 9mm screw length (Fig. 1) were used and supported bilaterally by first premolars and first molars. All appliances were activated 2 quarter turns at the time of delivery (0.25 mm per each) then they were activated quarter turn at the morning and another one at the evening [13–17] by the patient or parents for 15 days, thus reaching the total amount of expansion of about 8 mm in all subjects. [18–22]
The MSE jackscrew with 4 holes was consisted of two soft titanium arms connected to two molar bands and 4 miniscrews (1.8mm in diameter, 11mm in length) were Inserted to enhance posterior and superior expansion of the maxilla Through bicortical engagement.
The patients’ follow-up was necessary to verify and confirm the accuracy of appliance activation. The screw was fixed with a ligature wire, and masked by a small piece of flowable composite and maintained for six months as retainer after the last activation of active screw. No additional orthodontic intervention was initiated in both jaws till the retention phase has finished.
Sixty CBCT were taken to all patients, Thirty before the start of the orthodontic expansion (T1), and thirty after the last activation immediately after removal of the expander (T2) about six months, (Fig. 3a, b and c).
Planmeca ProMax 3D Mid was used to capture CBCT images (at T1 and T2). 90 kV, 12.5 mAs, 20 × 17 mm field of view, Scan time: 18 S. Exposure time: 6.22 S. 194 degrees. With a voxel size of 200 mm.
All CBCT were converted as a DICOM (digital imaging and communications in medicine), data files and were reconstructed at 0.3 mm increments then analyzed by using Romexis software (version 5.3.4.39USA).
The patients positioning by adjusting the Frankfort horizontal plane (FHP) parallel to the floor, laser beams act as a guide for orientation of the head according to FHP. The following volumetric measurements were assessed according to previous studies. [23–32]
Manual segmentation of the maxillary sinus using segmentation tool in the software was made by tracing of the sinus layer by layer in the coronal cross section until the last layer.
Sagittal view showing completed volume segmentation and its volume in mm3. 3D volume reconstruction of the maxillary sinus. (Fig. 3a, b and c).
Statistical analysis
Data management and statistical analysis were performed using the Statistical Package for Social Sciences (SPSS) version 18. Numerical data were summarized using mean, standard deviation and confidence intervals. Data were explored for normality by checking the data distribution and using Kolmogorov-Smirnov and Shapiro-Wilk tests. Comparisons between groups with respect to normally distributed numeric variables were compared by one-way analysis of variance (ANOVA) test, followed by Bonferroni post hoc test. Comparison between pre and post values and between left and right was performed by paired t test.