Hyunsup Shim

Abstract

The purpose of this study is to compare two mechanical debonding methods on ceramic brackets (TP MXi and 3M Clarity) and a metal bracket (GAC OmniArch) with four different bonding materials (light-cured, one-step chemical-cured, two-step chemical-cured, and Fuji GIC) in clinical simulation, where the diametral force was applied on the handle of the pliers. The effectiveness of mechanical debonding technique was determined by evaluating the following variables: the amount of force required to debond the bracket, the amount of residual adhesive remaining on the enamel surface, the frequency of unexpected bracket failure, and the prevalence of visible enamel damage. The results indicated that the bracket type, bracket design for debonding, debonding instruments, and the adhesives all affect the debonding strength. The following conclusions were derived from the study: 1) Ligature wire cutter method was more efficient at debonding MXi ceramic brackets than metal brackets. 2) Weingart method was more efficient at debonding Clarity ceramic brackets than metal brackets. 3) Ligature wire cutter method was more efficient than Weingart method at debonding metal brackets. 4) Ceramic brackets required significantly smaller force for debonding than metal brackets did, maintaining a greater margin of safety. 5) Overall, the most common site of bond failure was at the adhesive bracket base interface without damaging enamel surface of the teeth. 6) All the four resin bonding systems were efficient in bonding metal and ceramic brackets in terms of debonding strength. 7) There were no unexpected failures or fractures of the bracket wings during debonding procedure. 8) The diametral force application on the handles of the pliers can be one of the ways of measuring both the actual force that the clinician exerts on the pliers and the load that the brackets and enamel of the teeth experience.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Willis L. Schlenker

Second Advisor

Joseph M. Caruso

Third Advisor

Daniel A. Flores

Fourth Advisor

Carlos Munoz

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1999

Date (Title Page)

9-1999

Language

English

Library of Congress/MESH Subject Headings

Dental Debonding; Orthodontic Brackets; Dental Materials

Type

Thesis

Page Count

vii; 56

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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