Influence of placement techniques on Vickers and Knoop hardness of class II composite resin restorations

Poskus, Laiza Tatiana; Plácido, Eliane; Cardoso, Paulo Eduardo Capel

doi:10.1016/j.dental.2003.10.006

Cited by 63 publications

(51 citation statements)

References 29 publications

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“…Nonetheless, the three hardness values of the investigated resin composites were significantly correlated with each other (Table 4). The high correlation coefficients between HV and HK (r=0.92, p<0.01) and between HV/HK and BH (r=0.81-0.85, p<0.01) were supported by the literature data 13,66,67) . It thus appears that the hardness tests can be used interchangeably for assessing the other mechanical properties.…”

Section: Correlation Between the Mechanical Propertiessupporting

confidence: 72%

Investigation of the correlation between the different mechanical properties of resin composites

et al. 2013

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The aim of this study was to investigate the relationship between the different mechanical properties with the filler fraction of various resin composites. Mechanical properties of eighteen different resin composites were investigated in this study; flexural strength (FS), flexural modulus (FM), fracture toughness (FT), compressive strength (CS), diametral tensile strength (DTS), Barcol hardness (BH), Vickers hardness (HV), and Knoop hardness (HK). The mean values of mechanical properties and the filler fractions (V f ) obtained from the literature and the manufacturer were analyzed using Pearson's correlation test at p<0.01. The relationships were compared with the data retrieved from previous studies. Strong correlations between V f and BH/HV/HK and V f and FM were evident in the results of the present study and these results were supported by the retrieved data from previous studies. The other relationships between mechanical properties, such as that between FS and FM and between CS and HV were not significant.

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Section: Correlation Between the Mechanical Propertiessupporting

confidence: 72%

Investigation of the correlation between the different mechanical properties of resin composites

et al. 2013

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“…Adequate polymerization results in enhanced physical properties [19] and decreased cytotoxicity of dimethacrylate-based composites [20]. Different factors such as filler particle size and loading, polymerization initiator concentration [21,22], monomer type and amount, the shade and translucency of the material [23], intensity and wavelength of the light source, as well as irradiation time [24] can influence the DC of dental composite materials.…”

Section: Introductionmentioning

confidence: 99%

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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“…2 In addition, the duration of light activation needs to be increased for deep cavities to make up the increased light scattering caused by the depth of the restoration to assure proper cure of the composite resin at the bottom. 2,3,4 These procedures increase the chair time and the risk of saliva contamination between increments. 5 A new category of resin composites was introduced for bulk-filling deep and wide dental cavities providing a faster and easier procedure than the traditional incremental restoration technique.…”

Section: Introductionmentioning

confidence: 99%

“…1 However, there are some concerns in class II restorations with deep proximal boxes with respect to the degree of monomer conversion and polymerization shrinkage strain. 2 To reduce the inherent polymerization shrinkage, and achieve adequate curing of the resin, composite resins must be inserted by an incremental oblique layering technique. 2 In addition, the duration of light activation needs to be increased for deep cavities to make up the increased light scattering caused by the depth of the restoration to assure proper cure of the composite resin at the bottom.…”

Section: Introductionmentioning

confidence: 99%

“…2 To reduce the inherent polymerization shrinkage, and achieve adequate curing of the resin, composite resins must be inserted by an incremental oblique layering technique. 2 In addition, the duration of light activation needs to be increased for deep cavities to make up the increased light scattering caused by the depth of the restoration to assure proper cure of the composite resin at the bottom. 2,3,4 These procedures increase the chair time and the risk of saliva contamination between increments.…”

Section: Introductionmentioning

confidence: 99%

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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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Influence of placement techniques on Vickers and Knoop hardness of class II composite resin restorations

Cited by 63 publications

References 29 publications

Investigation of the correlation between the different mechanical properties of resin composites

Investigation of the correlation between the different mechanical properties of resin composites

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

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

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