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Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study

OBJECTIVE: The aim of this study was to evaluate the effect of increased exposure time and light intensity on microhardness of cured composite through different thicknesses of tooth structure in primary teeth. MATERIALS AND METHODS: One hundred and seventy cylindrical resin composite specimens were...

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Autores principales: Mazhari, Fatemeh, Ajami, Behjatolmolok, Moazzami, Saied Mostafa, Baghaee, Bahareh, Hafez, Bahareh
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Medknow Publications & Media Pvt Ltd 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4813436/
https://www.ncbi.nlm.nih.gov/pubmed/27095897
http://dx.doi.org/10.4103/1305-7456.178316
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author Mazhari, Fatemeh
Ajami, Behjatolmolok
Moazzami, Saied Mostafa
Baghaee, Bahareh
Hafez, Bahareh
author_facet Mazhari, Fatemeh
Ajami, Behjatolmolok
Moazzami, Saied Mostafa
Baghaee, Bahareh
Hafez, Bahareh
author_sort Mazhari, Fatemeh
collection PubMed
description OBJECTIVE: The aim of this study was to evaluate the effect of increased exposure time and light intensity on microhardness of cured composite through different thicknesses of tooth structure in primary teeth. MATERIALS AND METHODS: One hundred and seventy cylindrical resin composite specimens were prepared. All specimens were divided into 17 experimental and control groups. “Light-emitting diode” light curing unit (LCU) applied directly or through 1, 2, and 3 mm thicknesses tooth slices for experimental groups. The irradiation protocols were 25 and 50 s at 650 mW/cm(2) and 15 and 30 s at 1100 mW/cm(2). The “quartz-tungsten-halogen” LCU (400 mW/cm(2)) for 40 s was used in control group. Microhardness was measured by the Vickers hardness test. RESULTS: Indirectly cured specimens and those cured through a 1 mm thick tooth structure, an increase in intensity caused hardness drop. In the specimens cured through 2 and 3 mm thick tooth structures, increased intensity and/or exposure time did not show any appropriate changes on microhardness. CONCLUSION: Irradiation through a 1.0 mm thick tooth slice resulted in reduced microhardness although it was still within the clinically acceptable level. The hardness values of the specimens cured through 2 or 3 mm thick tooth slices fell below the clinically acceptable level even after doubling the exposure time and/or light intensity.
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spelling pubmed-48134362016-04-19 Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study Mazhari, Fatemeh Ajami, Behjatolmolok Moazzami, Saied Mostafa Baghaee, Bahareh Hafez, Bahareh Eur J Dent Original Article OBJECTIVE: The aim of this study was to evaluate the effect of increased exposure time and light intensity on microhardness of cured composite through different thicknesses of tooth structure in primary teeth. MATERIALS AND METHODS: One hundred and seventy cylindrical resin composite specimens were prepared. All specimens were divided into 17 experimental and control groups. “Light-emitting diode” light curing unit (LCU) applied directly or through 1, 2, and 3 mm thicknesses tooth slices for experimental groups. The irradiation protocols were 25 and 50 s at 650 mW/cm(2) and 15 and 30 s at 1100 mW/cm(2). The “quartz-tungsten-halogen” LCU (400 mW/cm(2)) for 40 s was used in control group. Microhardness was measured by the Vickers hardness test. RESULTS: Indirectly cured specimens and those cured through a 1 mm thick tooth structure, an increase in intensity caused hardness drop. In the specimens cured through 2 and 3 mm thick tooth structures, increased intensity and/or exposure time did not show any appropriate changes on microhardness. CONCLUSION: Irradiation through a 1.0 mm thick tooth slice resulted in reduced microhardness although it was still within the clinically acceptable level. The hardness values of the specimens cured through 2 or 3 mm thick tooth slices fell below the clinically acceptable level even after doubling the exposure time and/or light intensity. Medknow Publications & Media Pvt Ltd 2016 /pmc/articles/PMC4813436/ /pubmed/27095897 http://dx.doi.org/10.4103/1305-7456.178316 Text en Copyright: © European Journal of Dentistry http://creativecommons.org/licenses/by-nc-sa/3.0 This is an open access article distributed under the terms of the Creative Commons Attribution NonCommercial ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non commercially, as long as the author is credited and the new creations are licensed under the identical terms.
spellingShingle Original Article
Mazhari, Fatemeh
Ajami, Behjatolmolok
Moazzami, Saied Mostafa
Baghaee, Bahareh
Hafez, Bahareh
Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title_full Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title_fullStr Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title_full_unstemmed Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title_short Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study
title_sort microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: in vitro study
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4813436/
https://www.ncbi.nlm.nih.gov/pubmed/27095897
http://dx.doi.org/10.4103/1305-7456.178316
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