Abstract

The view of not expanding mandibular canines to accommodate incisor crowding because of the fear of relapse of of the incisors has been generally accepted in orthodontics for many years. Most studies that have investigated expanded mandibular canine stability have concluded that they could not be permanently expanded to any degree. By adding another variable (rapid midpalatal expansion) to canine expansion it was thought that this might possibly increase canine expansion stability.

The purpose of this research was to determine if the stability of the expanded canines through 1st permanent molars was enhanced by concomitant rapid expansion of the midpalatal suture thus allowing lower incisor crowding to be resolved without the necessity of premolar extraction.

Of approximately 350 cases that were reviewed who had rapid palatal expansion only ten were found that met the criteria selected for this study. These criteria were:

  1. nonextraction treatment
  2. rapid midpalatal expansion achieved
  3. suture opening device stabilized a minimum of three months
  4. four or more millimeters of mandibular crowding measured on beginning plaster models.

Intercanine, interpremolar, and inter 1st permanent molar widths were measured on beginning, ending, and two or more year post treatment models.

The millimeters of crowding was related to a cephalometric norm of one millimeter from the lower incisor to the A-Pogonion plane to evaluate whether lower incisors were advanced or canines, premolars, and molars were expanded.

Conclusions drawn form these measurements were:

  1. A tendency of increased stability was demonstrated for the expanded mandibular canines, premolars, and 1st permanent molars when done in conjunction with rapid midpalatal expansion.

  2. The mandibular canines exhibited the least amount of stability, the 2nd premolars the most stability with the 1st premolars slightly less, and the molars somewhat less than the premolars but more than the canines.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Roland D. Walters

Second Advisor

James R. Wise

Third Advisor

Raymond M. Sugiyama

Fourth Advisor

Ray M. Hymer

Fifth Advisor

Grenith J. Zimmerman

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1978

Date (Title Page)

5-1978

Language

English

Library of Congress/MESH Subject Headings

Orthodontics; Palate

Type

Thesis

Page Count

v; 38

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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