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

First Advisor

Sundaralingam Premaraj

Date of original Performance / Presentation

January 2024

Publication Date / Copyright Date

1-1-2024

Abstract

Objectives: The objective of this Finite Element Analysis (FEA) was to determine and compare the forces and moments of forces (Mf) exerted by three different types of Maxillary Segmental Distalizers (MSDs): JVBarre® 4D - metallic (JVB), Carriere® Motion 3D™ Appliance - metallic and clear (CMA) in conjunction with Class II elastics on the following teeth: maxillary right canine (UR3), maxillary right first molar (UR6), mandibular right first molar (LR6), and mandibular right second molar (LR7). Additionally, the Von Mises stress and displacement maps of the MSDs were characterized. Background: CMA is a MSD used in the initial phase of correction of Class II malocclusions. Documented side effects of CMA include extrusion of U3s and distal tipping of U6s. JVB was designed to minimize the above side effects and is expected to produce bodily movements of teeth. Methods: MSDs were bonded to UR3 and UR6 of a life-size, plastic model of a human skull. Anterior bite turbos were bonded on maxillary central incisors, and buttons were bonded on the LR6 and LR7 for Class II elastics application: 1/8”, 6 ½ oz and 3⁄16”, 8 oz on the MSDs. FEA 3D model was generated using the digital scan of the skull and patient-specific CBCT images. Using FEA, forces and the Mf along three planes of space were quantified and compared between different MSDs. Displacement and Von Mises stress maps of the MSDs were generated. Results: Metallic CMA exerted 24.6% and 7.6% more distally directed forces on the UR3 and UR6 respectively compared to that of JVB, when the elastics were placed on LR6. Both types of CMA produced 15.3% and 10% more mesially directed forces on LR6, and 45.5% and 48.5% more mesially directed forces on LR7, respectively than that of JVB. JVB exerted 19% less extrusive force on UR3 compared to metallic CMA when the elastics were placed on LR6.Furthermore, JVB exerted less mesio-buccally directed moment of force on UR3 and UR6, and less distal crown tipping of UR3 compared to that of both types of CMA. Elastic forces exerted were higher when the elastics were placed on LR7 instead of LR6 and 1/8”, 6.5 oz exerted higher elastic forces than the 3⁄16”, 8 oz. The 1/8”, 6.5 oz elastics exerted a statistically significant higher extrusion force on the LR7 than the 3⁄16”, 8 oz elastics. Displacement in JVB was less than that of both types of CMAs, while the clear CMA showed the least Von Mises stress. For all types of MSDs, the highest stress and displacement were observed at the hooks of the structures. Conclusions: Compared to JVB, both types of CMA are capable of producing greater mesio-buccal rotations of UR6 and exerting larger mesially directed forces on lower molars. In contrast, compared to metallic CMA, JVB could correct the Class II buccal segment relationship with minimal extrusion of maxillary canines and minimal distal tipping of maxillary canines and molars. Wearing of 1/8”, 6.5 oz elastics on lower second molars produced Class II forces of greater magnitude.

Disciplines

Dentistry

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