Student Theses, Dissertations and Capstones

Document Type

Thesis - NSU Access Only

Degree Name

Master of Science (M.S.) in Dentistry

Copyright Statement

All rights reserved. This publication is intended for use solely by faculty, students, and staff of Nova Southeastern University. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

Department

College of Dental Medicine

Publication Date / Copyright Date

2012

Publisher

Nova Southeastern University

Abstract

A thesis submitted to the College of Dental Medicine of Nova Southeastern University of the degree of Master of Science in Dentistry.

Objective: This study was conducted to examine the changes in the inclination of mandibular incisors and their alveolar bone dimensions between pre- and post- non-extraction orthodontic treatment, measured using cone beam computed tomography (CBCT) images. The study measured the association of the pre- and post- labial and lingual bone measurements with the pre- and post- treatment incisor inclination by comparing the incisor-mandibular plane angle (IMPA). Background: Teeth move through bone by extensive osseous adaptation within the alveolar process. It is a common belief in orthodontics that alveolar bone follows tooth movement. As a tooth moves, bone will remodel around the alveolar socket usually in a 1:1 ratio of bone resorption to bone apposition. However, conflicting evidence in the orthodontic literature questions whether the anterior alveolar bone is able to remodel and follow the direction and quantity of tooth movement. Many studies have shown that the width of the alveolar bone and the lingual and labial cortical plates set limitations on how much anterior tooth movement can be accomplished without negative effects such as periodontal problems, root resorption or fenestrations. Methods: Pre- and post- non-extraction orthodontic treatment CBCT scans of twenty Class I molar patients with mild to moderate crowding were used to observe the buccal and lingual width and incisor inclination of each of the patient's four mandibular incisors. The labial and lingual alveolar bone dimensions were measured pre-treatment and post-treatment at 6 mm apical to the CEJ and at the apex of each tooth. The inclination of the incisors (using IMPA) of both time points was also documented. Results: A Fisher's exact test and a Cramer's V test were performed. The results showed statistical significance between the change in bone of the incisors and the change in their inclination at the buccal 6mm, buccal apex, lingual 6mm and lingual apex. There was also statistical significance found between the change in bone between the buccal apex and lingual apex of the LR1, LR2, LL1, and LL2. Conclusion: Our results showed that the change in bone of the lower incisors is correlated to the change in their inclination. This suggests that incisors were tipped within the confines of the mandibular anterior alveolar process, or the alveolar process bent and remodeled around the incisors in the same direction of tooth movement or a combination of the two.

Disciplines

Dentistry | Orthodontics and Orthodontology

Keywords

Health and environmental sciences, Anterior mandible, Cone beam computed tomography, Mandibular incisors

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