Student Theses, Dissertations and Capstones

Document Type


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.


College of Dental Medicine

First Advisor

Shiva Khatami

Publication Date / Copyright Date



Nova Southeastern University


Introduction: Demand for orthodontic treatment is increasing amongst patients of all ages, including adults. Typically, a comprehensive orthodontic treatment requires two to three years of active tooth movement, which may not seem desirable for adults. Orthodontic appliances can impede proper oral hygiene and increase the risk of white spot lesions and caries. Other sequel of lengthy orthodontic treatment includes external apical root resorption, increased plaque index, increased level of dental caries and subsequent gingivitis, root resorption, gingival inflammation, and bone loss. Reduction of treatment time may reduce the risk of the undesirable sequel and increase the acceptance rate of orthodontic treatment by adults. Some patients may be willing to pay more and undergo additional procedures in order to decrease treatment time and the side effects of orthodontic treatment. However, some of these procedures need a referral to a periodontist or an oral surgeon to be performed, they may be lengthy and involve an invasive surgical procedure in addition to adding expenses to the comprehensive orthodontic treatment. Therefore, there is a growing interest among orthodontists in adopting adjunctive procedures to accelerate tooth movement that are considered “minimally-invasive” to accelerate tooth movement. The available evidence to date suggests that both Low Level Laser Therapy (LLLT) and Micro osteo-perforations (MOP) have the potential to be adopted in routine clinical practice with no additional distress for the patient. However, despite the large majority of reports, no study has been conducted to compare the relative efficiency of the two techniques. This study aims to explore and compare the effects of two minimally invasive techniques to accelerate orthodontic tooth movement. Methods: 45 Sprague Dawley rats will be randomly divided into 3 groups of accelerated tooth movement with Propel® (n=15), LLLT (n=15), and control group without any intervention except orthodontic appliance (n=15). An orthodontic closed Nickel Titanium (NiTi) coil spring was extended from the central incisors to the maxillary first molars of each rat on the left side. The distance between the first molars and the central incisors was measured intraorally, using a digital caliper. Five rats from each group were euthanized at the 14 and 21 days. The histological observations and the rate of tooth movement elicited the differences between the two techniques and the control group. Results: Out of 45 rats, 40 remained healthy and demonstrated normal increased body weight throughout the 3-week experimental period. 5 rats were lost during the study due to hypothermia, since the temperature of the procedure room was set too low. At the end of the study all appliances stayed in place without breakage and all experimental groups demonstrated movement of the tests molars at the end of the experimental periods. There were no statistically significant differences in the clinically measured distance of the central incisor to the test molars across the groups in either of the time points (p < 0.000), neither between groups (p =0.49), or the interaction of groups by time (p =0.971). A post hoc Tukey test showed that day-21 was significantly different from the baseline and also from 14 days to 21 days in all groups at p < 0.01. However, no difference was found between baseline and 14 days in control and propel groups (p value: 0.11 and 0.06). The evaluation of osteoclast numbers in two different time intervals (T1, T2) demonstrated the mean amount of 1.86, 2.00 and 9.57 for control, propel and LLLT groups, respectively. The evaluation of osteoclast numbers in two different time intervals (T1, T2) demonstrated the mean amount of 58.29, 60.57 and 209.86 for control, propel and LLLT groups, respectively. The amount of root resorption was evaluated based on the presence of root resorption on the external border of roots. It seems that the laser group demonstrated higher frequency and severity of root resorption compared to control and propel groups. Conclusions: The rate of tooth movement did not differ significantly between the propel and laser groups at three-time intervals (baseline, 14 days, and 21 days). The number of osteoclasts was significantly higher in the LLLT group compare to the propel and control groups at both time points. However, the number of osteoblasts was significantly higher only at 14 days in these groups. LLLT demonstrated more significant histological changes compared to propel and seems to have a more significant effect on acceleration of tooth movement in a rat model.




Orthodontic treatment, Rate of tooth movement, Osteoclasts, Low Level Laser Therapy



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