Influence of shade and irradiation time on the hardness of composite resins
This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37ºC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.
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Fundação Odontológica de Ribeirão Preto
2007
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oai:scielo:S0103-644020070003000102008-01-02Influence of shade and irradiation time on the hardness of composite resinsDella Bona,ÁlvaroRosa,ViníciusCecchetti,Dileta resin composite shade hardness irradiation time This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37ºC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.info:eu-repo/semantics/openAccessFundação Odontológica de Ribeirão PretoBrazilian Dental Journal v.18 n.3 20072007-01-01info:eu-repo/semantics/articletext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-64402007000300010en10.1590/S0103-64402007000300010 |
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Della Bona,Álvaro Rosa,Vinícius Cecchetti,Dileta Influence of shade and irradiation time on the hardness of composite resins |
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Della Bona,Álvaro Rosa,Vinícius Cecchetti,Dileta |
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Della Bona,Álvaro |
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Influence of shade and irradiation time on the hardness of composite resins |
title_short |
Influence of shade and irradiation time on the hardness of composite resins |
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Influence of shade and irradiation time on the hardness of composite resins |
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Influence of shade and irradiation time on the hardness of composite resins |
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Influence of shade and irradiation time on the hardness of composite resins |
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influence of shade and irradiation time on the hardness of composite resins |
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This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37ºC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2. |
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Fundação Odontológica de Ribeirão Preto |
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2007 |
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http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-64402007000300010 |
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AT dellabonaalvaro influenceofshadeandirradiationtimeonthehardnessofcompositeresins AT rosavinicius influenceofshadeandirradiationtimeonthehardnessofcompositeresins AT cecchettidileta influenceofshadeandirradiationtimeonthehardnessofcompositeresins |
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