Eric Looi

Abstract

The purpose of this study was to investigate the effects of mandibular expansion by orthopaedic and surgical procedures in the growing rat mandible.

Sixty-four 35 day old Sprague Dawley Harlan rats were divided into four groups of 16 rats each and categorized as the control, orthopaedic expansion, surgery without graft and surgery with graft respectively. Prefabricated appliances were used for orthopaedic expansion of the mandibles and maintaining surgical expansion at the symphysis in the respective groups. Oxytetracycline were given intraperitoneally to mark areas of bone remodeling. Half the number of rats from each group were sacrificed at the end of the 7-day and 21-day experimental periods.

Analysis of variance and multiple range test showed that the horizontal and oblique dimensions of the experimental groups were significantly shorter than the control and the vertical dimension showed no significant difference compared to the control at the end of the 21-day experimental period. Graphically, the lateral morphology of the mandible of the experimental groups appeared to be less rectangular than the control. Histological sections of the condylar cartilage of the experimental groups showed reduced thickness and cellular activity. Fluorescence microscopy showed increased bone remodeling at the site of expansion and at the lower border of the body of the mandible extending over the buccal side. There were less bone remodeling in the experimental groups compared to the control around the condylar neck and ramus region. These observations indicated that the expansion procedures had affected and interfered with the normal growth and development of the mandible. The surgical expansion procedure seemed to interfere less with growth and development of the growing mandible than the orthopaedic expansion procedure.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Willis L. Schlenker

Second Advisor

Christer Engstrom

Third Advisor

Roland D. Walters

Fourth Advisor

Philip P. Boyne

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1986

Date (Title Page)

6-1986

Language

English

Library of Congress/MESH Subject Headings

Mandible; Growth

Type

Thesis

Page Count

vi; 67

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

Download

Share

COinS