Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements

Flury, Simon; Lussi, Adrian; Hickel, Reinhard; Ilie, Nicoleta

doi:10.1007/s00784-013-0924-4

Cited by 40 publications

(80 citation statements)

References 24 publications

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“…In the present study, the thickest tested materials were 2 mm, which was enough to reduce the DC of resin cement (13). Flury et al (23) showed that the irradiances from two curing units decreased by >80% through IPS Empress CAD and IPS e.max CAD (Ivoclar Vivadent) 1.5-mm discs. However, the DC for the RelyX Unicem 2 was not reduced, which corroborates the results of this study.…”

Section: Discussionmentioning

confidence: 99%

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

et al. 2015

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This study evaluated the effects of indirect restorative materials, curing conditions and time on the degree of conversion (DC) of a dual-cured resin cement using infrared spectroscopy. The resin cement (RelyX Unicem 2, 3M ESPE) was applied to the diamond surface of a horizontal attenuated-total-reflectance unit and activated using one of following conditions: self-cure, direct light exposure, light exposure through indirect restorative materials (resin nano-ceramic: Lava Ultimate, 3M ESPE or feldspathic ceramic: Vita Blocks Mark II, Vita Zahnfabrik). Four thicknesses (0.5, 1.0, 1.5 or 2.0 mm) of each indirect material were analyzed, and the light-activation was performed using a blue LED light. Data (n=5) were analyzed by three-way ANOVA, Tukey's post hoc and Dunnett's tests (a=5%). No significant differences in DC were observed between indirect materials of similar thickness. All groups exhibited higher DC after 10 min than after 5 min. At both times points, the self-cure group exhibited significantly lower DC than all the light exposure groups. Only when the overlying indirect restoration had a thickness of 2 mm did DC decrease significantly. The presence of a thick, indirect restoration can decrease the DC of resin cement. DC after 10 min was higher than after 5 min. The self-cure mode yielded lower DC than the light-activating one.

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Section: Discussionmentioning

confidence: 99%

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

et al. 2015

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“…Second-generation LED curing units typically reach irradiances of 1,200 to 1,500 mW/ cm 2 . The third-generation of LED curing units contains multiple diodes, and recently a third-generation LED curing unit was marketed (VALO, Ultradent), which is claimed to reach irradiances of up to 3,200 mW/cm 2 depending on the chosen mode 14) . Dental visible light curing materials generally contain a diketone-type photoinitiator that absorbs light in the 400-to 500-nm range covered by the blue light from the visible spectrum.…”

Section: Discussionmentioning

confidence: 99%

Effect of new light curing units on microleakage and microhardness of resin sealants

Bani

Tiralı

2016

Dent. Mater. J.

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To determine new developed light curing units with shorter curing times effects on microleakage and microhardness values for resin fissure sealants. Resin filled sealant (UltraSeal-XT), resin unfilled sealant (Delton Type-II) and ormocer-based sealant (Admira-Seal) were light cured with a quartz-tungsten-halogen (QTH), two LED light and a high power LED. Two hundred and forty extracted human molars were randomly allocated into four groups according to used light-curing unit and three subgroups were formed for three different fissure sealant materials. Specimens were immersed in 0.5% basic fuchsin for 24 h, sectioned and examined under a stereomicroscope, and scored for marginal microleakage. Knoop hardness number (KHN) readings were measured after 48 h. Statistical analyses of test were found in significant difference both microleakage and microhardness values between the various light curing units. The time saving approaches in the curing light were determined higher microhardness, although it was found in higher microleakage.

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“…Assim, na presente pesquisa, este dispositivo foi empregado com o objetivo de demonstrar o comportamento das duas resinas, considerando diferentes resinas e espessuras. Outros trabalhos também empregam radiômetros manuais com a finalidade de mensurar a perda de luz através de diferentes materiais [24][25][26] . Outro aspecto relevante refere-se à intensidade média de luz empregada durante o experimento que foi de 1000 mW/cm 2 , a qual é considerada alta.…”

Section: Discussionunclassified

Atenuação da intensidade de luz e profundidade de polimerização de resinas compostas

Werlang¹,

Dalfovo²,

Neiva

et al. 2016

Arq Odontol

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RESUMOObjetivo: Avaliar a atenuação da luz através de diferentes espessuras de resina composta e a profundidade de polimerização. Materiais e Métodos: Foram utilizadas as resinas Opallis e Llis de esmalte (E) e de dentina (D), na cor A3. Para atenuação da luz foram empregadas matrizes metálicas (6,0mm de diâmetro e espessuras de 0,5, 1,0, 1,5 e 2,0mm), as quais foram posicionadas na janela de leitura do radiômetro e a intensidade de luz medida antes e após a interposição do material. A profundidade de polimerização foi realizada seguindo os procedimentos recomendados na ISO 4049 (2000 INTRODUÇÃOO emprego de resinas compostas é uma prática bastante aceita e difundida, no que se refere à realização de restaurações imperceptíveis tanto nos dentes anteriores quanto posteriores. Isto se deve ao fato do material possuir propriedades ópticas que favorecem seu mimetismo à estrutura dental adjacente 1 . As resinas compostas empregadas atualmente são fotoativadas por meio de luz visível, cujo comprimento de onda varia entre 400 e 500 nanômetros (nm), com pico de absorção em aproximadamente 470 nm. Neste intervalo, a molécula fotoiniciadora (a caforoquinona) é ativada e promove o início da reação de polimerização 2 . Porém, vários parâmetros devem ser observados e respeitados para que o material final alcance as propriedades esperadas. Dentre eles destacam-se: intensidade de luz, tempo de exposição, comprimento de onda adequado para sensibilizar a molécula da canforoquinona, distância entre a ponta do aparelho fotopolimerizador e a resina, bem como a formulação do material 2-6 . Entretanto, quando a luz atinge o material, vários fenômenos podem ocorrer, incluindo absorção, reflexão e dispersão. Isto significa que apenas uma parte da radiação luminosa pode ser transmitida pelo material 3,5,7 . Como consequência, regiões mais profundas receberão menor quantidade de luz, o que pode reduzir ou impedir que a reação de polimerização ocorra 5,6 . Estes fatores resultam na atenuação da luz à medida que atravessa o material, fazendo com que na superfície da restauração a polimerização seja maior do que nas regiões mais profundas, desta forma, determinando a profundidade de polimerização do material 6,8 . Clinicamente, isto significa que a resina composta deve ser inserida e polimerizada de forma incremental.Vale ressaltar que uma polimerização inadequada pode afetar as propriedades físicas, mecânicas e biológicas do material, levando ao insucesso clínico, caracterizado pelo aumento da microinfiltração marginal, diminuição da microdureza e da estabilidade de cor, causando manchamento na restauração, bem como um aumento na quantidade de monômeros residuais, responsáveis por eventuais

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Light curing through glass ceramics with a second- and a third-generation LED curing unit: effect of curing mode on the degree of conversion of dual-curing resin cements

Abstract: When light curing a given cement, the higher irradiances of the third-generation LED curing unit resulted in similar DC compared to the second-generation one, though at shorter light curing times.

Cited by 40 publications

References 24 publications

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

Effect of new light curing units on microleakage and microhardness of resin sealants

Atenuação da intensidade de luz e profundidade de polimerização de resinas compostas

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