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

Cristina Godoy

Date of original Performance / Presentation

January 2026

Publication Date / Copyright Date

1-1-2026

Abstract

Objective: The interest in micro and nanoparticles (MNPs) has increased due to the alarming rate at which they are accumulating in the ecosystem and their potentially detrimental effect on humans. In the body, MNPs are prone to bioaccumulation where they have the potential to cause cellular damage via inducing oxidative stress and DNA damage. Its infiltration into our bodies is becoming increasingly known as recent studies found microplastics within placentas and the human heart. Elastomeric materials are polymers made of plastics or latex and are frequently used throughout orthodontic treatment. This study was conducted to evaluate the amount and size of MNPs that are released from a variety of commonly used orthodontic elastomeric materials over time. Methods: Three of the most commonly used orthodontic elastomers- elastomeric ligatures (o rings), power chains, and rubber bands – were weighed to 150 mg and immersed in artificial saliva for specific periods of time (twenty four hours, forty eight hours, seventy two hours, two weeks, and four weeks) at 37 degrees Celsius. Nanoparticle release in solution was caried out using the Zetasizer that gave estimates of the size and relative quantity of MNP in solution. Further quantification of microparticle released from the elastomers was carried out via filtration of MNP out of solution, and quantification of the particles via microscopy. Results: All weights of elastomeric material had low standard deviations so results are not due to material variability. Immersion time, elastomer type, and their combination influence microparticle size with elastomer type having the largest effect (η² = 0.028). Post Hoc Tukey HSD revealed all statistically significant values except for 24 hours vs 2 weeks (p = 0.975), 24 hours vs 4 weeks (p = 0.917), and 2 weeks vs 4 weeks (p = 1.000). All elastomer types were statistically significant (p = 0.000). Rubber band released the most microparticles, followed by power chain, and o ring released the least amount of microparticles. Each elastomer type released different particle sizes and each had a specific and different degradation pattern. Conclusion: The three most commonly used elastomeric materials – elastomeric o rings, power chains, and rubber bands – were evaluated to determine micro and nanoparticle release. Power chain released the largest microparticles, followed by o ring, and rubber band released the smallest. Regarding quantity of microparticles, rubber band released the most, followed by power chain, and o ring released the least. Power chain, o ring, and rubber band all had different and specific nanoparticle degradation patterns. Power chain presented with bulk degradation early on, o ring presented with early release of larger nanoparticles, and rubber band had delayed degradation or aggregation of nanoparticles.

Disciplines

Dentistry

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