Effect of Thermo-Mechanical Aging and Repressing on Fracture Resistance of Lithium Disilicate Crowns
DOI:
https://doi.org/10.14295/bds.2021.v24i3.2545Abstract
Objective: The recycling of heat pressed lithium disilicate glass-ceramic leftover material has been reported to be done by dental laboratories. The effect of this procedure on the fracture resistance of single crowns is unknown, especially when it is functioning inside the oral cavity with subsequent exposure to temperature changes and cycles of mastication. Material and Methods: A total of 28 lithium disilicate glass-ceramic crowns (IPS emax Press) were constructed and randomly assigned into two groups (n = 14); Group (P): Included crowns fabricated from new e.max ingots. Group (R): Included crowns fabricated from repressed e.max buttons. Specimens of each group were divided into two equal subgroups (n = 7) according to whether the aging of specimens will be performed or not before fracture resistance testing. Subgroup (N), samples were subjected to fracture resistance without thermo-mechanical aging, while subgroup (A), samples were subjected to thermo-cycling and cyclic loading before being subjected to fracture strength testing. Different methods; SEM, XRD, EDAX were used to characterize the properties of lithium disilicate glass-ceramics before and after repressing. Results: The highest statistically significant fracture resistance value was recorded for the subgroup (RN) repressed/non-aged, followed by the subgroup repressed/aged (RA), while the lowest statistically significant mean value was recorded for the subgroup pressed/aged (PA). There was no significant difference between pressed/non-aged (PN) and repressed/aged (RA) subgroups. Conclusion: Repressing of leftover buttons may increase the fracture resistance of IPS emax Press crowns. Thermo-mechanical aging may negatively affect the fracture resistance of IPS emax Press crowns, yet Repressing may decrease this effect. Clinical implications: This is a novel approach that targets a point of research that has not been investigated before. It elaborates how repressing may decrease the effect of aging and increase the fracture resistance of lithium disilicate crowns. Thus, recycling of lithium disilicate glass ceramics might decrease its failure and prolong their serviceability.
Keywords
Fracture resistance; Heat pressed; Lithium disilicate; Recycling; Repressing; Thermo-mechanical aging.
Downloads
Downloads
Published
How to Cite
Issue
Section
License
Brazilian Dental Science uses the Creative Commons (CC-BY 4.0) license, thus preserving the integrity of articles in an open access environment. The journal allows the author to retain publishing rights without restrictions.
=================
COPYRIGHT TRANSFER AND RESPONSIBILITY STATEMENT
(PDF)
For all articles published in the BDS journal, copyright is retained by the authors. Articles are licensed under an open-access Creative Commons CC BY 4.0 license, meaning that anyone may download and read the paper for free. In addition, the article may be reused and quoted, provided that the original published version is cited. These conditions allow for maximum use and exposure of the work while ensuring that the authors receive proper credit. All metadata associated with published articles is released under the Creative Commons CC0 Universal Public Domain Dedication.
Before the submission, authors must obtain permission to reproduce any published material (figures, schemes, tables, or any extract of a text) that does not fall into the public domain or for which they do not hold the copyright. Permission should be requested by the authors from the copyright holder (usually the Publisher, please refer to the imprint of the individual publications to identify the copyright holder).
The authors hereby attest that the study is original and does not present manipulated data, fraud, or plagiarism. All names listed made a significant scientific contribution to the study, are aware of the presented data, and agree with the final version of the manuscript. They assume complete responsibility for the ethical aspects of the study.
This text must be printed and signed by all authors. The scanned version should be submitted as supplemental file during the submission process.