Microhardness of a Resin Cement Polymerized by Light‐Emitting Diode and Halogen Lights through Ceramic

Hooshmand, Tabassom; Mahmoodi, Nasrin; Keshvad, Alireza

doi:10.1111/j.1532-849x.2009.00449.x

Cited by 21 publications

(30 citation statements)

References 24 publications

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“…There is no internationally recognized standard for adequate depth of cure as measured by the relative hardness method 17 . For proper depth of cure, a relative hardness value (100 x hardness of lower surface/hardness of top surface) must be higher than 80% 27 .…”

Section: Discussionmentioning

confidence: 99%

“…Some studies have shown that LED is now as effective as QTH curing light units 4,17,28,30 . LED units have an expected lifetime of several thousand h without significant degradation of light flux over time and no filters are required, since their spectral output falls conveniently within the absorption spectrum of the camphoroquinone photoinitiator (400-500 nm) 18,31,34 .…”

Section: Introductionmentioning

confidence: 99%

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Hardening of a dual-cure resin cement using QTH and LED curing units

et al. 2010

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ObjectiveThis study evaluated the surface hardness of a resin cement (RelyX ARC) photoactivated through indirect composite resin (Cristobal) disks of different thicknesses using either a light-emitting diode (LED) or quartz tungsten halogen (QTH) light source.Material and MethodsEighteen resin cement specimens were prepared and divided into 6 groups according to the type of curing unit and the thickness of resin disks interposed between the cement surface and light source. Three indentations (50 g for 15 s) were performed on the top and bottom surface of each specimen and a mean Vickers hardness number (VHN) was calculated for each specimen. The data were analyzed using two-way ANOVA and Tukey-Kramer test was used for post-hoc pairwise comparisons.ResultsIncreased indirect resin disk thickness resulted in decreased mean VHN values. Mean VHN values for the top surfaces of the resin cement specimens ranged from 23.2 to 46.1 (QTH) and 32.3 to 41.7 (LED). The LED curing light source produced higher hardness values compared to the QTH light source for 2- and 3-mm-thick indirect resin disks. The differences were clinically, but not statistically significant. Increased indirect resin disk thickness also resulted in decreased mean VHN values for the bottom surfaces of the resin cement: 5.8 to 19.1 (QTH) and 7.5 to 32.0 (LED). For the bottom surfaces, a statistically significant interaction was also found between the type of curing light source and the indirect resin disk thickness.ConclusionsMean surface hardness values of resin cement specimens decreased with the increase of indirect resin disk thickness. The LED curing light source generally produced higher surface hardness values.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hardening of a dual-cure resin cement using QTH and LED curing units

et al. 2010

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“…The success of indirect esthetic restorations depends mainly on the luting agent, which should guarantee an effective bonding between the restoration and the dental substrate, preserving the marginal seal (1). Despite the variety of commercially available cements, there is no ideal cement for all clinical situations.…”

Section: Introductionmentioning

confidence: 99%

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

et al. 2010

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This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC film. Light curing (40 s) was carried out through resin discs (2, 3, 4 or 5 mm) with a halogen light positioned 0, 1, 2 or 3 mm from the resin surface. After storage, specimens were sectioned for hardness measurements (top, center, and bottom). Data were subjected to split-plot ANOVA and Tukey's test (a=0.05). The increase in resin disc thickness decreased cement hardness. The increase in the distance of the light-curing tip decreased hardness at the top region. Specimens showed the lowest hardness values at the bottom, and the highest at the center. Resin cement hardness was influenced by the thickness of the indirect restoration and by the distance between the light-curing unit tip and the resin cement surface.

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“…Vários fatores podem influenciar a polimerização do cimento empregado na cimentação de coroas confeccionadas em cerâmica: a composição, espessura, opacidade e a cor do material cerâmico podem atenuar a passagem da fonte luz e, consequentemente, diminuir a porcentagem de polimerização do cimento (BLACKMAN; BARGHI; DUKE, 1990, EL-MOWAFY;RUBO, 2000, SOARES;SILVA;FONSECA, 2006YOSHIDA;ATSUTA, 2008, ILIE;HICKEL, 2008, PAZIN et al, 2008MAHMOOD;KESHVAD, 2009, NORONHA-FILHO et al, 2010, VALENTINO et al, 2010. As características dos substratos e do agente cimentante também são fatores determinantes do resultado final da restauração (CARVALHO et al, 2004a, CEBALLOS et al, 2007, MANSO et al, 2011.…”

Section: Introdução 19unclassified

Análise da qualidade de polimerização, por meio de testes de microdureza, de um cimento resinoso utilizado na cimentação de coroas totais em preparos com diferentes substratos

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Microhardness of a Resin Cement Polymerized by Light‐Emitting Diode and Halogen Lights through Ceramic

Cited by 21 publications

References 24 publications

Hardening of a dual-cure resin cement using QTH and LED curing units

Hardening of a dual-cure resin cement using QTH and LED curing units

Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

Análise da qualidade de polimerização, por meio de testes de microdureza, de um cimento resinoso utilizado na cimentação de coroas totais em preparos com diferentes substratos

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