Abstract

This study was conducted to examine, retrospectively, orthodontic and orthopedic changes resulting from quad helix expansion therapy in mixed and permanent dentition stages. Twenty-one subjects with an average age of 10.2 years who experienced an expansion of at least 3 mm with the quad helix appliance were selected for this study. The subjects were evaluated according to facial type and age for both short and long-term stability. Plaster dental casts and posteroanterior (frontal) radiographs were evaluated at the beginning of treatment (T1), at the completion of Phase 1 or full treatment (T2), and approximately two years following the completion of treatment (T3). Maxillary first intermolar distance evaluations on the plaster casts showed no statistically significant effects of facial type and age on intermolar width for the sample evaluated. No significant difference in intermolar distance existed from T2 to T3, indicating stability of expansion. The overall maxillary first molar inclinations measured on the frontal cephalogram tended to decrease from T1 to T2 (roots tended to become more upright). No significant decrease in overall inclination from T2 to T3 existed. Both facial type and age had no statistically significant effect on maxillary first molar inclination. Results of J Point evaluation for orthopedic change show that there is a significant difference from T1 to T2 and T1 to T3. No statistically significant difference existed between T2 and T3. It was concluded that neither facial type nor age have a significant effect on changes seen in maxillary first molar inclination or intermolar distance from T1 to T2, T2 to T3, or T1 to T3 for the sample studied. Short and long term stability were demonstrated by the fact that all overall measurements had no significant decrease from T2 to T3. Orthopedic changes were evidenced by the increase in J Point distance from T1 to T2 especially if the increase is greater than Ricketts norm of 0.6 mm per year.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate School

First Advisor

R. David Rynearson

Second Advisor

Joseph M. Caruso

Third Advisor

Michael J. Fillman

Fourth Advisor

Jay S. Kim

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2000

Date (Title Page)

6-2000

Language

English

Library of Congress/MESH Subject Headings

Orthodontic Appliances, Removable; Palatal Expansion Technique

Type

Thesis

Page Count

viii; 25

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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