The purpose of this study was to use cone beam computed tomography (CBCT) to quantitatively evaluate and compare skeletal expansion and alveolar tipping of the maxilla at the maxillary canine (Cl), first premolar (PI), second premolar (P2) and first molar (Ml) after rapid maxillary expansion (RME). Transverse effects to the maxillary suture, nasal width and maxillary sinus were also assessed. Included in the study were thirty consecutive patients (17 males and 13 females; mean age = 13.8 + 1.7 years) requiring RME using Hyrax appliances as part of their comprehensive orthodontic treatment. The pre-RME and post-RME measurements of palatal and buccal maxillary widths (PMW and BMW), palatal alveolar angle (PAA), nasal width (NW), nasal floor width (NEW), and maxillary sinus width (MSW) at Cl, PI, P2 and Ml were compared using Wilcoxon signed-rank, Kruskall-Wallis and Wilcoxon rank sum tests at the significant level of a = .05. To evaluate the level of association, Pearson correlation analyses were performed (a = .05). The results of this study suggest that skeletal expansion of the maxilla exhibits a triangular pattern with the wide base in the anterior, accounting for 55% of total expansion at PI, 45% at P2, and 38% at Ml. An additional alveolar bending/tipping component accounts for 6% of total expansion at PI, 9% at P2, and 13% at Ml. The remaining orthodontic (dental tipping) portion of total expansion is 39% at PI, 46% at P2, and 49% at Ml. RME also produces a statistically significant increase in nasal width and decrease in maxillary sinus width (p < .0001). Retention time showed a significant negative correlation to the change in palatal maxillary width at Cl, P2 and Ml (p < .05), rate of appliance expansion only displayed a significant correlation with palatal maxillary expansion at PI and P2 (p < .05), and age exhibited no statistically significant association with any parameters (p > .05).

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


Graduate Studies

First Advisor

Joseph M. Caruso

Second Advisor

James Farrage

Third Advisor

Jay Kim

Fourth Advisor

Kitichai Rungcharassaeng

Fifth Advisor

Guy Taylor

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Palatial Expansion Technique; Cone-Beam Computed Tomography; Maxillary Sinus; Orthodontics, Corrective; Nasal Cavity -- radiography



Page Count

xi; 35

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives