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

Mazhari, F. and Ajami, B. and Moazzami, S. M. and Baghaee, B. and Hafez, B. (2016) Microhardness of composite resin cured through different primary tooth thicknesses with different light intensities and curing times: In vitro study. European Journal of Dentistry, 10 (2). pp. 203-209.

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Abstract

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/cm2 and 15 and 30 s at 1100 mW/cm2. The "quartz-tungsten-halogen" LCU (400 mW/cm2) 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. © 2016 European Journal of Dentistry.

Item Type: Article
Additional Information: Cited By :1 Export Date: 16 February 2020 Correspondence Address: Hafez, B.; NIOC Health OrganizationIran; email: alazkoo@gmail.com
Uncontrolled Keywords: Composite resin Curing time Light intensity Microhardness Primary tooth
Subjects: WU Dentistry. Oral surgery
Divisions: Mashhad University of Medical Sciences
Depositing User: mr lib4 lib4
Date Deposited: 01 Mar 2020 11:02
Last Modified: 01 Mar 2020 11:02
URI: http://eprints.mums.ac.ir/id/eprint/13083

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