Student Theses, Dissertations and Capstones

Document Type

Thesis

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

Publication Date / Copyright Date

2018

Publisher

Nova Southeastern University

Abstract

Objective: High translucency zirconia has been developed for esthetically demanding dental cases with the objective of improving light transmittance. The purpose of this in vitro study is to compare the translucency and flexural strength of high translucency zirconia with conventional zirconia and lithium disilicate ceramics, all of which are options for indirect dental restorative applications. Methods: Three dental ceramic materials were selected: Group 1: conventional zirconia; group 2: high translucent zirconia; and group 3: lithium disilicate glass-ceramic. Fifteen disk-shaped specimens (10mm in diameter) of each material were fabricated at 0.5mm, 0.75mm, and 1 mm thicknesses as subgroups A, B, and C respectively (n=135). The morphologies of the specimens were observed by a scanning electron microscopy at 5000X magnifications. Translucency and flexural strength of all specimens were measured using spectrophotometry and biaxial flexural testing respectively. The data was analyzed by ANOVA followed by post-hoc test (p<0.05). Results: Conventional Zirconia and lithium disilicate showed the highest and lowest mean flexural strength values respectively. Flexural strength of all 3 ceramic materials did not show significant difference with different material thicknesses. Lithium disilicate and conventional zirconia of equal thicknesses showed the highest and lowest translucency values respectively. Translucency of all 3 ceramic materials decreased with increasing material thickness. Conclusion: High translucency zirconia did not show superior translucency compared to lithium disilicate. Thus, high translucency zirconia should be carefully used in the esthetic zone depending on the translucency needed for a successful restoration. The flexural strength of conventional zirconia was significantly higher than high translucency zirconia and lithium disilicate. Therefore, the mechanical properties of high translucency zirconia may be of concern when planning for more than three unit FPDs in the posterior area.

Disciplines

Dentistry

Keywords

Zirconia, Light transmittance, Dental ceramics

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