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Effect of light intensity on linear shrinkage of photo‐activated composite resins during setting
Author(s) -
INOUE K.,
HOWASHI G.,
KANETOU T.,
MASUMI S.,
UENO O.,
FUJII K.
Publication year - 2005
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.2004.01363.x
Subject(s) - shrinkage , composite number , intensity (physics) , light intensity , materials science , composite material , chemistry , optics , physics
summary The purpose of this investigation was to examine the effects of light intensity on linear shrinkage of photo‐activated composite resins during setting. The materials used were four commercially available photo‐activated composite resins. Three light‐irradiation instruments were selected and prepared so as to obtain four light intensities (200, 480, 800 and 1600 mW cm −2 ). The linear shrinkage during setting was examined 10 min after light irradiation using a trial balance plastometer, and the specimen thickness was 2·0 mm for all materials. The depth of cure was examined according to the test method described in the International Organization for Standardization (ISO/FDIS 4049: 2000(E)). In measuring the linear shrinkage 60 s from the start of light irradiation for 10 s, there was a significant correlation ( r = 0·89–0·94) between the amount of linear shrinkage and the light intensity: an increase in light intensity produced a greater linear shrinkage. Furthermore, there was a significant correlation ( r = 0·92–1·0) between the linear shrinkage and the irradiation time: an increase in irradiation time resulted in a greater linear shrinkage. Values of the depth of cure ranged from 1·69 to 3·75 mm.