Degree of conversion and microhardness of dental composite resin materials

Marović, Danijela; Pandurić, Vlatko; Tarle, Zrinka; Ristić, Mira; Šariri, Kristina; Demoli, Nazif; Klarić, Eva; Janković, Bernard; Prskalo, Katica

doi:10.1016/j.molstruc.2012.10.062

Cited by 49 publications

(49 citation statements)

References 41 publications

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“…8,15 When it comes to determine the depth of cure by the VH profiles along the depth of a specimen, one school of thought is to accept the depth where the hardness value attains 80% of the maximum VH measured near the top surface exposed to light curing. 21,22 In this study, maximum VH has been achieved at the bottom surface for all materials tested, the 80% rule, which use the hardness of top surface would not be meaningful. Should the approach used in this study become acceptable, a definitive number may be established for determining the depth of cure.…”

Section: Discussionmentioning

confidence: 77%

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

et al. 2017

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The effect of restoration depth on the curing time of a conventional and two bulk-fill composite resins by measuring microhardness and the respective radiosity of the bottom surface of the specimen was investigated. 1-, 3-and 5-mm thick washers were filled with Surefil SDR Flow-U (SDR), Tetric EvoCeram Bulk Fill-IVA (TEC) or Esthet-X HD-B1 (EHD), and cured with Bluephase ® G2 for 40s. Additional 1-mm washers were filled with SDR, TEC or EHD, placed above the light sensor of MARC ® , stacked with pre-cured 1-, 3-or 5-mm washer of respective material, and cured for 2.5~60s to mimic 2-, 4-and 6-mm thick composite curing. The sensor measured the radiosity (E B ) at the bottom of specimen stacks. Vickers hardness (VH) was measured immediately at 5 locations with triplicate specimens. Nonlinear regression of VH vs E B by VH=α[1-exp(-E B /β)] with all thickness shows that the values of α, maximum hardness, are 21.6±1.0 kg/mm 2 for SDR, 38.3±0.6 kg/mm 2 for TEC and 45.3±2.6 kg/mm 2 for EHD, and the values of β, rate parameter, are 0.40±0.06 J/cm 2 for SDR, 0.77±0.04 J/cm 2 for TEC and 0.58±0.09 J/cm 2 for EHD. The radiosity of the bottom surface was calculated when the bottom surface of each material attained 80% of α of each material. The curing times for each material are in agreement with manufacturer recommendation for thickness. It is possible to estimate time needed to cure composite resin of known depth adequately by the radiosity and microhardness of the bottom surface.

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Section: Discussionmentioning

confidence: 77%

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

et al. 2017

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“…Thus, higher DC does not necessarily result in higher mechanical properties [64,65]. In any case, KHN measurements do not provide any quantitative information on the actual change in reactive groups.…”

Section: Discussionmentioning

confidence: 95%

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

et al. 2014

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OBJECTIVES To evaluate the influence of irradiation time on degree of conversion (DC) and microhardness of high-viscosity bulk-fill resin composites in depths up to 6 mm. MATERIALS AND METHODS Four bulk-fill materials (Tetric EvoCeram Bulk Fill-TECBF; x-tra fil-XF; QuixFil-QF; SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were irradiated for 10, 20, or 30 s at 1,170 mW/cm(2). DC and Knoop microhardness (KHN) were recorded after 24-h dark storage at five depths: 0.1, 2, 4, 5, and 6 mm. Data were statistically analyzed using ANOVA and Bonferroni's post-hoc test ( = 0.05). RESULTS With increasing bulk thickness, DC and KHN significantly decreased for TEC. TECBF and SF showed a significant decrease in DC and KHN at 4-mm depth after 10-s irradiation, but no decrease in DC after 30-s irradiation (p > 0.05). XF and QF demonstrated no significant DC decrease at depths up to 6 mm after irradiation of at least 20 s. At 4-mm depth, all materials tested achieved at least 80 % of their maximum DC value, irrespective of irradiation time. However, at the same depth (4 mm), only XF and QF irradiated for 30 s achieved at least 80 % of their maximum KHN value. CONCLUSIONS Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation. CLINICAL RELEVANCE Minimum irradiation times stated by the manufacturers cannot be recommended for placement of highviscosity bulk-fill materials in 4-mm increments. Conclusions: Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation.Clinical relevance: Minimum irradiation times stated by the manufacturers cannot be recommended for placement of high-viscosity bulk-fill materials in 4-mm increments.

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“…As resinas compostas apresentam-se inicialmente em uma fase plástica, por meio da luz visível, emitida por aparelhos, ocorre sua polimerização, que deve ser de elevado grau para poder proporcionar as propriedades físico-mecânicas desejadas e minimizar os riscos de toxicidade ao complexo dentina-polpa 9 .…”

Section: Discussionunclassified

“…A FT-IR é utilizada para determinar o GC por intermédio da proporção de concentração de duplas ligações de carbono alifáticas antes e após a polimerização do material 9 . O percentual de duplas ligações de carbono alifáticas não convertidas (% C=C) é determinado pela taxa da intensidade de absorção entre ligações C=C (1.638 cm -1 ) e ligações C=O (1.730 cm -1 ), antes e após a polimerização.…”

Section: Introductionunclassified

Avaliação do grau de conversão de resinas compostas fotoativadas em diferentes tempos e potências

Lima¹,

Souza²,

Amorim³

et al. 2016

Rev. da Fac. de Odontologia, UPF

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Introdução: uma polimerização adequada é crucial para a obtenção das propriedades físicas ideais e o desempenho clínico das resinas compostas. Objetivo: avaliar o grau de conversão (GC) e dureza de resinas IntroduçãoDesenvolvidas por Bowen durante a década de 1960, as resinas compostas à base de BisGMA passaram por transformações com o intuito de melhorar suas propriedades mecânicas e estéticas 1 . Concomitantemente à evolução desses materiais, os pacientes buscam cada vez mais a excelência estética ao sorrir, o que leva ao desenvolvimento de resinas que, além de devolver a forma e função do dente, favoreçam a harmonia do sorriso de maneira natural. Sendo assim, por proporcionar ao profissional a capacidade de restabelecer a estética do sorriso, confeccionar restaurações em dentes posteriores, além do seu baixo custo, quando comparadas

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Degree of conversion and microhardness of dental composite resin materials

Cited by 49 publications

References 41 publications

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

Comparing depth-dependent curing radiant exposure and time of curing of regular and flow bulk-fill composites

Influence of irradiation time on subsurface degree of conversion and microhardness of high-viscosity bulk-fill resin composites

Avaliação do grau de conversão de resinas compostas fotoativadas em diferentes tempos e potências

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