Light scattering in polycrystalline alumina with bi-dimensionally large surface grains

Yoshimura, Humberto Naoyuki; Goldenstein, Hélio

doi:10.1016/j.jeurceramsoc.2008.03.008

Cited by 23 publications

(31 citation statements)

References 17 publications

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“…The interaction of light with the ceramic material depends on the amount (fraction), size and crystal composition and glassy matrix (9). Furthermore, the light beam scatters when there is a difference in refractive index between two phases, so that the higher the refractive index and the number of phases, the higher the scattering effect, resulting in a more opaque material (25). Lithium-disilicate pressed glass ceramic has a greater crystal fraction compared to feldspathic ceramic.…”

Section: Discussionmentioning

confidence: 99%

“…Lithium-disilicate pressed glass ceramic has a greater crystal fraction compared to feldspathic ceramic. When light beam hits this material, it will pass through a series of intercepts (interface between two phases) resulting in greater light scattering and hence a greater opacity (25). In the feldspathic porcelain, the light beam travels longer distances in the same phase and crossing a smaller number of intercepts that could cause light scattering (9).…”

Section: Discussionmentioning

confidence: 99%

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Influence of Resin Cements on Color Stability of Different Ceramic Systems

et al. 2017

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The purpose of this study was to evaluate color stability of two dental ceramics cemented with two resin cements, assessing the color difference (ΔE 00 ) by the measurement of L*, a*, b*, c* and h* of transmittance. The combination of two ceramic system (feldspathic and lithium disilicate) and two resin cements -color A3 (RelyX ARC and Variolink II) resulted in 4 groups (n=5). Ten disks-shaped specimens were fabricated for each ceramic system (10x1.5 mm), etched with hydrofluoric acid (10%) and silanized prior to cementation. The color analysis was performed 24 h after cementation of the samples and after 6 months of storage in relative humidity by means of spectrophotometry. The ΔE 00 values were analyzed statistically by two-way ANOVA followed by the Tukey test (p<0.05). One-way ANOVA were calculated for the means of individual color coordinates (L*, a*, b*, c* and h*). Two-way ANOVA showed that only the ceramic factor was significant (p=0.003), but there was no difference for the cement factor (p=0.275) nor for the ceramic/cement interaction (p=0.161). The feldspathic ceramic showed the highest values of ΔE 00 . Variations in L*, a*, b*, c* and h* were more significant for feldspathic ceramic. In conclusion, storage alters similarly the optical properties of the resin cements and feldspathic porcelain was more susceptible to cement color change after aging.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Influence of Resin Cements on Color Stability of Different Ceramic Systems

et al. 2017

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“…Although this interlocked microstructure provides good mechanical properties, it has problems related to the optical behavior of the restoration, as light is heavily scattered within the material, especially at interfaces due to a mismatch between the refractive indexes of both phases. Light scattering significantly decreases total light transmittance through the material [8]. In addition, residual porosity significantly reduces the mechanical properties of the biocomposite, [5] and is considered the most significant optical heterogeneity in its microstructure, causing significant light scattering and therefore decreasing light transmittance [8].…”

Section: Introductionmentioning

confidence: 99%

“…Light scattering significantly decreases total light transmittance through the material [8]. In addition, residual porosity significantly reduces the mechanical properties of the biocomposite, [5] and is considered the most significant optical heterogeneity in its microstructure, causing significant light scattering and therefore decreasing light transmittance [8].…”

Section: Introductionmentioning

confidence: 99%

Influence of Multi-cycle Infiltration on Porosity and Optical Properties of Glassinfiltrated Alumina Biocomposites for Dental Restorations

Yoshimura¹

2016

J. Dent. Sci. Ther

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Glass-infiltrated alumina biocomposites have been largely used in Dentistry due to their biocompatibility, high potential to mimic the natural dentition and good marginal adaptation. However, their optical and mechanical properties are jeopardized by the presence of residual porosity in the final structure. The objective of this study was to increase light transmittance of alumina-based biocomposites that are infiltrated with a lanthanum-containing aluminosilicate glass by means of increasing the number of infiltration cycles from one to three. The influence of the number of cycles on both residual porosity and optical properties was assessed. The infiltration cycles were carried out at 1200°C for 95 min. After each cycle the residual glass was removed and an additional glass layer was placed over the alumina preform. The SEM images showed that specimens infiltrated with three cycles had denser microstructure, with a residual porosity of 1.8 vol%, whereas specimens submitted to only one cycles showed residual porosity of 4.5 vol%. Transmittance increased 55% for specimens subjected to three infiltration cycles, while light scattering coefficient was reduced by 45% and the contrast ratio was reduced by 23%. These results indicate that the higher number of cycles resulted a more translucent material due to lower porosity and lower pore size (smaller than 3.2 µm). In conclusion, this work showed that multi-cycle infiltration is effective in reducing residual porosity and improving light transmittance of the biocomposite tested.

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“…As principais heterogeneidades ópticas são superfícies rugosas, fases secundárias (incluindo poros) e contornos de grão. A dispersão do feixe de luz que ocorre através das interfaces é evidenciada quando existe uma diferença no índice de refração entre as duas fases; quanto maior for esta diferença, mais intenso será o espalhamento (12).…”

Section: Comportamento óPtico Dos Materiais Cerâmicosunclassified

Desenvolvimento de metodologia para fabricação de cerâmica de 'Y IND.2'O IND.3' transparente

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Light scattering in polycrystalline alumina with bi-dimensionally large surface grains

Cited by 23 publications

References 17 publications

Influence of Resin Cements on Color Stability of Different Ceramic Systems

Influence of Resin Cements on Color Stability of Different Ceramic Systems

Influence of Multi-cycle Infiltration on Porosity and Optical Properties of Glassinfiltrated Alumina Biocomposites for Dental Restorations

Desenvolvimento de metodologia para fabricação de cerâmica de 'Y IND.2'O IND.3' transparente

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