Date of Award
Summer 2023
Document Type
Master's Essay
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Mehta, Shivam
Second Advisor
Liu, Dawei
Third Advisor
Del Santo, Marinho
Abstract
Objective: The objective of this study was to evaluate the short-term and long-term hard tissue changes with miniscrew-assisted rapid palatal expansion (MARPE) and rapid palatal expansion (RPE) compared to a matched control group with voxel based superimposition and three dimensional cone-beam computed tomography (CBCT) analysis. Methods:After IRB review, a total of 180 cone beam computed tomography (CBCT) scans were analyzed for 60 patients with a mean age of 13.9 years at 3 time points: pretreatment (T1), Post-Expansion (T2), and Post-treatment (T3). Patients were divided into 3 groups: MARPE, RPE, and controls. Voxel-based superimposition was performed for CBCTs from T1 to T2 and T1 to T3 using the anterior cranial base as a reference. The hard-tissue surfaces were extracted after the superimposition procedure. Nine landmarks (nasion, A point, pogonion, left and right alar bases, zygoma, and gonion were analyzed. In all time points, the results were tested against no change within groups by paired t-test, and the mean changes were compared among the three groups by ANOVA F test. Pearson correlation coefficients, 95% confidence intervals, and P values were calculated for correlations between changes from T1 to T2 or from T1 to T3. Results: In the short term within groups, MARPE and RPE groups saw the pogonion move downwards, both alar bases move laterally, left zygoma move laterally, and both gonions move downward and backward A-point moved forward in RPE in the short term. The controls saw no significant changes in the short term. Between groups saw similar changes in the short term with MARPE and RPE for the pogonion, alar bases, and left gonion. However, no changes were observed between the three groups in the long term. Conclusion: There were significant differences in pogonion, alar bases, and gonion between MARPE, RPE, and control groups in the short term. All the hard tissue changes were transient however, as there were no differences between the three groups in any of the landmarks in the long term.