Date of Award

1-1-2011

Embargo Period

1-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Pediatric Dentistry and Orthodontics

College

College of Dental Medicine

First Advisor

Ron Bell

Second Advisor

Luis Leite

Third Advisor

Jing Zhou

Abstract

Introduction: The first-order toe-in angle of the maxillary first molar is an important aspect of orthodontics and occlusion. Many variables contribute to the amount of distal offset expressed such as bracket slot dimensions, the amount of toe in angle built into the prescription of the bracket, bracket placement, bracket deformation, and tooth morphology. The purpose of this study is to mathematically predict the degree of first-order toe in angle loss with various archwire dimensions in various molar tube width preprogrammed brackets. Methods: Molar brackets from 3M Unitek, American Orthodontics™ (AO), Great American Orthodontics™ (GAC), Ormco™, Opal™, Rocky Mountain Orthodontics™ (RMO) and TP™ orthodontics were all evaluated to achieve a range of molar tube widths available. The range was from 2mm to 6mm. The relationship between the bracket depth (x), bracket width (y), arch wire depth (z), prescription toe in angle (θ), and the theoretical toe-in angle loss (α) was trigonometrically formulated. The degree of first-order loss was predicted by solving these conditional equations. Results: The computations indicated that as the width of the molar tube increased, the toe in angle loss decreased, thus the expressed distal offset angle increased. In a given molar tube width, as you increased the depth of the archwire size one size, the toe in angle loss decreased 1-2 degrees. Conclusions: It is recommended that clinicians consider ways to improve the proper distal offset in the upper first molar by using a prescription in their molar tube based on the width of the molar bracket tube they are implementing and on their finishing archwire.

Rights

All rights reserved. Copyright is held by the author.

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