Abstract

With the advent of lower third molar enucleation in the 7 to 10 year old comes the potential for abuse because the operation is fast and easy to perform. The rationale could be, "they will probably impact any way." If this is done without benefit of a growth forecast to project future dental needs a great disservice may be performed.

This study was designed to provide a simplified method to predict space for the lower third molar. Frankfort Horizontal (FH), Pterygoid Root Vertical (PTV), Xi, Upper first molar and lower second molar were the major landmarks to be used on a lateral cephalometric head film.

Before treatment (T1), end of retention (T3) and out of retention (T5) cephalometric tracings from 37 orthodontically treated cases were studied. They represented a time span of about 11 years. The measurements of 6 to PTV and Xi to 7 were correlated and used to project molar position at maturity by adding 1 millimeter per year along the occlusal plane.

The actual fate of the lower third molar was recorded in the hope it could be used to predict what to expect from the known T1 positions. Data were subjected to computer analysis for means, standard deviations, linear correlation and regression analysis for Xi to 7 and 6 to PTV.

T1 and T5 data were divided into two groups, impacted and nonimpacted. Within each group was a further division of extracted bicuspids and non-extracted bicuspids. The means for Xi to 7 and 6 to PTV for each group was recorded.

Xi to 7 and 6 to PTV at maturity was projected by adding 1 millimeter per year to these measurements at T1 until maturity. A comparison of the means of each group indicated no correlation between predicted molar position and actual fate of the lower third molars. For this sample the lower third molar space could not be predicted by adding 1 millimeter per year to the T1 measurement for 6 to PTV nor Xi to 7.

It was recommended that a growth forecast, using possibly the arcial method, be performed for all enucleation operations.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

James R. Wise

Second Advisor

J. Miford Anholm

Third Advisor

Virgil V. Heinrich

Fourth Advisor

Arthur J. Morgan

Fifth Advisor

John K. Pearson

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1980

Date (Title Page)

6-1980

Language

English

Library of Congress/MESH Subject Headings

Tooth Eruption; Tooth Extraction.

Type

Thesis

Page Count

vi; 28

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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