The objective of this study was to quantitatively evaluate, via CBCT, the dental and osseous effects of patients who had completed comprehensive orthodontic treatment with rapid maxillary expansion (RME) in conjunction with Ricketts prescription brackets. Thirty consecutive patients (16 males, 14 females; mean age = 13.9  1.9 years) who required RME as part of their orthodontic treatment and had pre-RME (T1), post-RME (T2) and final orthodontic (T3) CBCT images were included in the study. Thirteen patients had 2-banded, while 17 had 4-banded appliances. Measurements of interdental distance (ID), interdental angle (IA), buccal bone thickness (BBT) and buccal marginal bone level (BMBL) of the first premolar (P1), second premolar (P2) and first molar (M1) at T1, T2 and T3 were made and recorded. This data was compared using Friedman, Kruskal-Wallis, Wilcoxon Signed Rank and Mann-Whitney U-tests (α = 0.05). To determine which variables were associated with changes in ID, IA, BBT and BMBL, Kendall's Tau correlation analyses were used (α = 0.05). The results of this study suggest that the immediate effects of RME are uniform dental expansion from anterior to posterior, buccal crown tipping and reduction of both BBT and BMBL. In comparison to P1 and M1, P2 exhibited more buccal crown tipping (p = .010) and less reduction in BBT and BMBL immediately after RME. Long term effects of RME noted in this study included greater relapse of dental expansion at M1, which led to greater overall dental expansion maintained at P1 and P2. Also of note was the bone rebound for both BBT and BMBL, on all teeth, by the end of orthodontic treatment. At T3, patients with 4-banded appliances exhibited statistically significant greater overall BBT reduction at P1 (p = .036) and more tipping on P2 immediately after RME (p = .026). Significant correlations (p < .05) noted in this study between the changes in BBT and BMBL at various time points indicated that vertical bone changes can be expected when there is an evidence of horizontal bone change and that the greater the initial bone reduction, the greater the bone rebounded.

LLU Discipline

Orthodontics and Dentofacial Orthopedics


Orthodontics and Dentofacial Orthopedics


School of Dentistry

First Advisor

Rungcharassaeng, Kitichai

Second Advisor

Caruso, Joseph M.

Third Advisor

Leggitt, V. Leroy

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded

January 2012

Date (Title Page)




Library of Congress/MESH Subject Headings

Facial Bones - physiology; Orthodontics, Corrective; Oral Surgical Procedures; Palatal Expansion Technique; Cone-Beam Computed Tomography; Treatment Outcome;

Subject - Local

Rapid Maxillary Expansion; Fixed Orthodontic Treatment; Dental Bone Stability; Buccal Bone Stability; Coronal Imaging; Computed tomography; Rapid Palatal Expansion; Maxillary growth; Mandibular growth; Osseous effects



Page Count

56 p.

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 & Dissertations

Collection Website



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