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

Jeffrey Thompson

Date of original Performance / Presentation

January 2019

Publication Date / Copyright Date

1-1-2019

Abstract

ABSTRACT COMPARISON OF THE FRICTIONAL RESISTANCE OF DIFFERENT WIRE DIMENSIONS IN CONVENTIONAL AND SPEED SELF-LIGATING ORTHODONTIC BRACKET SYSTEMS: AN IN-VITRO STUDY. DEGREE DATE: DECEMBER 2019 COLLEGE OF DENTAL MEDICINE NOVA SOUTHEASTERN UNIVERSITY Thesis directed by: Jeffrey Thompson Ph.D., Committee Chair Patrick Hardigan Ph.D., Committee Member James Ginzler, D.D.S., M.S., Committee Member Introduction: The purpose of this study was to assess and compare the frictional characteristics of the SPEED and conventional twin bracket systems with stainless steel (SS) SPEED D-wires and rectangular stainless steel (SS) archwires of various dimensions. Background: To date, many studies in the orthodontic literature have investigated the frictional resistance encountered using sliding mechanics. This is the result of the complex interaction between the bracket, archwire, and the method of ligation. The claim of reduced friction with self- ligating brackets is often cited as a primary advantage over conventional brackets. However, the data regarding active self-ligated brackets is limited. Methods: In this in-vitro study, SPEED (Strite Industries, Cambridge, Ontario, Canada) and conventional twin brackets (American Orthodontics, Sheboygan, WI, USA) were tested on straight lengths of four different commercially available SS wires. SPEED brackets contain an active self-ligating nickel titanium (NiTi) clip to engage the archwire within the bracket slot while conventional twins require a removable component, either an elastomeric or steel ligature. A total of eight groups comprised of various bracket and archwire combinations were evaluated. Each bracket was bonded to a maxillary right first premolar melamine typodont tooth (Kilgore 6 International Inc., Coldwater, MI, USA) using Assure Plus Primer (Reliance Orthodontics, Itasca, IL, USA), Transbond XT resin (3M Unitek, St. Paul, MN, USA) and light cured for 20 seconds. The frictional force was measured by the Universal Testing Machine 8841 (Instron, Canton, MA, USA) with sliding velocity of 1 mm/min and a load cell of 1000 newtons. The average kinetic friction from each sample was represented by the mean of the plateau observed between 0.2 to 0.8 mm. Descriptive statistical analysis for each bracket/archwire combination with regard to mean kinetic frictional resistance was performed with a two-way analysis of variance (ANOVA) with a Tukey adjustment for bracket type and wire size. Results: The highest and lowest value of kinetic friction was recorded with the Conventional Twin/ 0.019” x 0.025” and SPEED/ 0.018” x 0.018” SPEED D-wire groups, respectively (4.48 and 0.83 N). There was a statistically significant effect of bracket/archwire combination on mean kinetic friction (N) at the p<.05 level for the eight combinations [F(7,88) = 189.13, p < 0.001]. Conclusions: SPEED active self-ligating metal brackets produce lower kinetic frictional force compared to conventional twin metal brackets. Considering the type of the archwire, the results demonstrated that in general SPEED D-wires had statistically significant lower kinetic frictional resistance compared to the comparable rectangular arch wires. Concerning the effect of archwire dimension, increasing the size of the archwire increases the frictional resistance with both rectangular and SPEED D-wires. However, this increase was greater in conventional twin brackets using rectangular wires compared to SPEED brackets using SPEED D-wires. This difference in the ratio of increasing kinetic frictional resistance with various sizes of D-wires in SPEED brackets compared to various sizes of rectangular archwires in twin brackets could be attributed to a combination of both the geometry of D-wires and the presence of the active spring clip.

Disciplines

Dentistry

Keywords

Friction; Orthodontics; Speed

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