Systematic approach to preparing ceramic–glass composites with high translucency for dental restorations

Yoshimura, Humberto Naoyuki; Chimanski, Afonso; César, Paulo Francisco

doi:10.1016/j.dental.2015.06.015

Cited by 14 publications

(8 citation statements)

References 31 publications

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“…As polymerization progresses, the refractive index of the organic matrix increases, and the mismatch with the filler is lessened. Provided that the degree of conversion is greater than 60–70%, materials can be tailored so that esthetic requirements are met [25]. However, for thicker increments or for regions of the restoration which are not properly accessed by the light [such as the bottom of a proximal box in deep a class II restoration], the scattering of light is more severe and the mismatch in refractive indices becomes a more serious concern [26].…”

Section: Discussionmentioning

confidence: 99%

Impact of thio-urethane additive and filler type on light-transmission and depth of polymerization of dental composites

Faria-e-Silva

Pfeifer

2017

Dental Materials

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Objectives This study evaluated the effects of filler type and the addition of thio-urethane oligomers on light-transmission, polymerization kinetics and depth of cure of resin composites. Methods BisGMA:UDMA:TEGMA (5:3:2 wt%) were mixed with 0 (control) or 20 wt% thio-urethane. Fillers with various sizes and refractive indices were included and refractive index (RI) measured. Unfilled resins were used as controls. The RIs of materials were measured before and after polymerization. The irradiance reaching the bottom of 3-mm thick specimens was measured during the polymerization. Degree of conversion to a depth of 5 mm was mapped. An optical bench was used to simultaneously follow conversion and light transmission. Results The addition of thio-urethane increased the RI for all composites. As expected, RI also increased with conversion for all materials. The one exception was for the material filled with OX-50, in which the RI of the composite decreased with conversion. In this case, the irradiance at the bottom of the 3 mm specimen was also the lowest among all groups. The addition of thio-utethanes had only minimal effect on light transmission within a filler type, but led to increased conversion in depth for all groups. The filler type itself had a greater effect on light transmission, and that correlated well with the degree of conversion. Significance The effect of the Thio-urethane addition on degree of conversion in depth was dependent on filler type. The additive can be tailored to improve the RI match with the filler to optimize light transmission in dental composites.

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Section: Discussionmentioning

confidence: 99%

Impact of thio-urethane additive and filler type on light-transmission and depth of polymerization of dental composites

Faria-e-Silva

Pfeifer

2017

Dental Materials

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“…The effectiveness of a systematic approach in designing specific glass compositions to prepare high translucent glass-infiltrated ceramic composites was verified [33]. First, it was necessary to calculate the viscosity of glass at the infiltration temperature.…”

Section: Translucency Of Dental Ceramicsmentioning

confidence: 99%

Translucency of Dental Ceramic, Post and Bracket

Lee¹

2015

Materials

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Translucency of dental ceramics, esthetic posts and orthodontic brackets was reviewed. Translucency parameter (TP) and contrast ratio (CR) are generally used for translucency evaluation. For the evaluation of translucency, two criteria such as the translucency of human teeth (TP = 15–19, 1 mm thick) and the visual perceptibility threshold for the translucency difference (∆CR > 0.07 or ∆TP > 2) were used. In ceramics, translucency differences were in the perceptible range depending on the type of material and the thickness. However, variations caused by the difference in the required thickness for each layer by the material and also by the measurement protocols should be considered. As to the translucency of esthetic posts, a significant difference was found among the post systems. Translucency was influenced by the bracket composition and brand, and the differences by the brand were visually perceptible.

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“…The refractive index of the glass investigated in this work, measured in a refractometer (2010/M Prism Coupler, Metricon), was 1.7411, which is 1.1% lower than that obtained for alumina (1.76). The glass composition used in this study was designed by a systematic approach developed by this research group, [19] aiming to minimize the difference between the refraction indexes of glass and ceramic phases in the biocomposite to achieve high transmittance.…”

Section: Resultsmentioning

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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Systematic approach to preparing ceramic–glass composites with high translucency for dental restorations

Cited by 14 publications

References 31 publications

Impact of thio-urethane additive and filler type on light-transmission and depth of polymerization of dental composites

Impact of thio-urethane additive and filler type on light-transmission and depth of polymerization of dental composites

Translucency of Dental Ceramic, Post and Bracket

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

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