Document Type

Thesis

Date of Degree

Spring 2010

Degree Name

MS (Master of Science)

Degree In

Orthodontics

First Advisor

Thomas E. Southard

Abstract

The purpose of this study was to substantiate previous claims that differential growth across the frontonasal suture occurs and if this differential growth pattern is caused by an increased mitotic rate of the nasal bone.

Two six week old New Zealand White Rabbits were given calcein 20mg/kg IA, demeclocycline 20mg/kg IA, and BrdU 40mg/kg IA on Days 1, 11, and 14, respectively. The animals were euthanized using Ketamine 31.6mg/kg IM and Pentobarbital 100mg/kg IV. The frontonasal suture was removed from the rabbit and divided into hemisections. The right hemisection was histologically processed using standard calcified methods which were modified and used for smaller bone sections at the Comparative Orthopaedic Research Laboratory, School of Veterinary Medicine, University of Wisconsin. The left hemisection was reserved for BrdU staining at the Central Microscopy Research Facility, University of Iowa. The resultant slides were imaged and photographed using an Olympus BX-40 microscope and measured using ImageJ software (NIH). Means and standard deviations were calculated for interlabel distance and mineral apposition rate (MAR).

All frontonasal suture sites demonstrated double fluorochrome labeling. Samples F2-2 and M2-1 demonstrated the predicted differential growth pattern. Samples F2-1 and M2-2 did not. No suture sites demonstrated positive staining for BrdU. Although the sample size was small (n=2), this may demononstrate a trend toward differential growth of the suture.

Due to the small sample size, the labeling protocol used in this study provided limited quantitative data. Although two sections did not demonstrate more bone deposition or faster mineral apposition rate of the nasal bone, it is important to consider that these sections were of poorer quality when compared to the other sections. Higher quality sections with clear, measurable margins showed a difference between frontal and nasal bone growth in both morphology and mineral apposition rate.

Keywords

Craniofacial suture, Frontonasal suture, Growth & Development, Rabbit

Pages

vii, 58 pages

Bibliography

Includes bibliographical references (pages 53-58).

Comments

This thesis has been optimized for improved web viewing. If you require the original version, contact the University Archives at the University of Iowa: http://www.lib.uiowa.edu/sc/contact/.

Copyright

Copyright 2010 Maura Josephine Vroman

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