Abstract

The purpose of this study was to use Cone Beam Computed Tomography (CBCT) images to quantitatively evaluate buccal bone changes of maxillary first premolar (P1), second premolar (P2) and first molar (M1) shortly after Rapid Maxillary Expansion (RME) and at the end of orthodontic treatment, as well as to evaluate the variables that may be associated with the short-term and long-term changes. Forty-seven consecutive patients (25 males and 22 females) with a mean age of 14.5years and who required RME as part of their orthodontic treatment and had pre-RME (T1) and post-RME (T2) CBCT images available were used for the short-term evaluation of the study. Of the forty-seven patients, ten patients (five males and five females) with a mean age of 14.1 years who have completed the orthodontic treatment, and had post-Treatment (T3) CBCT images, were used for the long-term evaluation of the study. The appliances used for expansion were either 2-banded or 4-banded Hyrax appliances. The T1, T2 and T3 measurements of buccal bone thickness (BBT), buccal marginal bone level (BMBL), interdental distance (ID), and interdental angle (lA) of P1, P2 and M1 were compared using Krustal-Wallis rank test and Mann-Whitney U-test at the significance level of α = 0.05. To determine which variables were associated with the changes in BBT, BMBL, ID, and lA, Pearson correlation analysis were performed (α = 0.05). The results of this study indicate that shortly following RME, dental expansion, dental tipping, reduction of BBT and BMBL are to be expected. P1 exhibited statistically significant more crown tipping than P1 and M1, and dental tipping showed correlation with the differential expansion. Age showed significant correlation with dental expansion. For M1, changes in BMBL and BBT exhibited significant correlation with dental expansion and differential expansion. There was more dental expansion experienced by P1 and P2 when 4-banded appliances were used as compared to 2-banded appliances and there was more BMBL loss experienced by all teeth and more BBT loss experienced by P2 when the 4-banded appliance was used. Long-term, M1 showed statistically significant dental relapse, however P1 and P2 showed some relapse as well. Although not statistically significant, all teeth showed clinically significant dental tipping relapse. There was statistically significant long-term BBT regain in all teeth, and although only M1 showed statistically significant BMBL regain, P1 and P2 showed clinically significant BMBL regain. The long-term BBT regain correlated with post-RME BBT loss and the long-term BMBL regain correlated with post-RME BMBL loss in all the teeth. Initial bone thickness showed correlation with long-term BMBL regain of M1. Therefore it can be concluded that up to 67%, 78%, 61% and 56% of the samples showed dental relapse, dental tipping relapse, BBT regain and BMBL regain respectively and that the more horizontal (BBT) and vertical (BMBL) bone loss observed post-RME, the more BBT and BMBL was regained at the end of the treatment.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate Studies

First Advisor

Joseph M. Caruso

Second Advisor

Jay Kim

Third Advisor

Kitichai Rungcharassaeng

Fourth Advisor

Guy Taylor

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2008

Date (Title Page)

12-2008

Language

English

Library of Congress/MESH Subject Headings

Facial Bones -- physiology -- dissertations; Orthodontics, Corrective; Oral Surgical Procedures; Palatal Expansion Technique -- therapy; Tomography, X-ray Computed; Maxillofacial Development; Cone-Beam Computed Tomography; Treatment Outcome; Time Factors; Endodontics -- instrumentation

Type

Thesis

Page Count

xi; 50

Digital Format

PDF

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.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

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

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