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

Chin-Yu Lin

Date of original Performance / Presentation

January 2023

Publication Date / Copyright Date

1-1-2023

Abstract

Objectives: The objective of this study was to compare the resistance to sliding (RS) of aesthetically coated and uncoated orthodontic archwires in ceramic brackets at various bracket angulations after water immersion up to 24 weeks. Background: Polymer-coated orthodontic wires have shown distinct material properties when compared to uncoated stainless-steel wires. Prolonged immersion in water, the most abundant component in human saliva, for up to four weeks has been shown to impact the resistance to sliding of polymer-coated wires, as a result of the plasticizing effects of water. Clinically, orthodontic wires could be used continuously for months. Therefore, the purpose of the current study was to compare RS of aesthetically coated and uncoated wires after water immersion for up to 24 weeks. Materials and Methods: Three groups of 0.019 x 0.025 inch stainless-steel archwires were utilized: uncoated (Group U), epoxy-coated (Group E), and Teflon-coated (Group T). Each group was immersed for 0 weeks (T0), 8 weeks (T8), 16 weeks (T16), or 24 weeks (T24), in distilled deionized water at 37°C. Maximum resistance to sliding (MRS) and average resistance to sliding (ARS) were measured by sliding the archwires through 0.022 inch slot ceramic brackets in either 0° (passive) or 3° (active) contact angle configurations using an Instron Universal testing machine. The data was then analyzed with a three-way ANOVA with independent variables of water immersion times, wire groups, and contact angles. Results: All three independent variables played significant roles in RS. Pair-wise comparison of MRS at 3° contact angle, the most clinical relevant RS, showed that Group U was in the highest group and Group T was in the lowest in all timepoints. A similar pattern was found for ARS at 3° contact angle. However, MRS and ARS at 0° contact angle showed distinct patterns different from that found in active configurations. Within wire-group comparisons of RS showed that the only statistically significant difference in MRS and ARS was found at a 3° contact angle in group E between T0 and T8. Conclusions: There are distinct differences in the resistance to sliding of aesthetically coated and uncoated wires after long-term immersion in water for up to 24 weeks, with Teflon coating displaying the lowest MRS in active bracket configuration at all immersion timepoints.

Disciplines

Dentistry

Keywords

Aesthetic; Friction; Immersion; Orthodontics; Polymers; Teflon

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