Abstract

Pre-adjusted bracket systems offer the clinician the convenience of working with both fewer in number and smaller magnitude adjustments in the archwire. The purpose of this study was to examine the normal variations in the thickness of the six maxillary anterior teeth and how this relates to anticipated first order bends in the archwire. A second purpose was to examine these same teeth for bilateral symmetry.

Thirty casts from the Loma Linda University completed treatment files were examined with respect to variations in the thicknesses of the crowns at the level of the archwire plane. From these, the mean difference between the thicknesses of the maxillary anterior teeth on this plane was determined.

Computer simulated pre-adjusted brackets were designed with faciolingual thicknesses to offset the mean differences in thickness of these teeth and align the incisal edges of the crowns at specified inclinations. This was done with respect to the mean thickness variations at a common crown long axis inclination from facial to lingual. These computer simulated brackets were compared with simulated control brackets of uniform thickness to assess the clinical value of a pre-adjusted appliance. The data was analyzed to determine the frequency and magnitude of first order bends which would have been required to align the incisal edges to a smooth arch form. Bilateral symmetry in these same dimensions was also examined.

Conclusions are presented showing frequency of first order archwire adjustments anticipated at varying levels of clinical acceptance of departure from smooth incisal edge arch forms. Pre-adjusted bracket systems with unbent archwires have the potential to deliver incisal edge alignment within 0.5 millimeters in sixty percent of patients in these teeth.

Bilateral symmetry was found to be within a small variance for the dimensions studied.

LLU Discipline

Orthodontics

Department

Orthodontics and Dentofacial Orthopedics

School

Graduate School

First Advisor

Roland D. Walters

Second Advisor

Norman S. Carter

Third Advisor

Joseph M. Caruso

Fourth Advisor

Michael J. Fillman

Fifth Advisor

Lawrence F. Andrews

Sixth Advisor

Raymond M. Sugiyama

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1991

Date (Title Page)

6-1991

Language

English

Library of Congress/MESH Subject Headings

Orthodontic Appliances; Tooth -- anatomy and histology

Type

Dissertation

Page Count

2 ii; 35

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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