BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI

More documents

Recommendations

Info

54 Irina Grădinaru et al. The CIE tristimulus values system uses 3 parameters (X,Y,Z), based on the spectral response functions defined by the CIE observer. Sometimes is used a CIE chromaticity diagram to define color. Fig.2 – Schematic representation of the interaction between the light source, the dental material and the observer after O’Brien. Fig. 3 – Schematic representation of the Munsell three-dimensional color system after O’Brien. The CIE color system (CIE L*a*b*) uses L* (lightness), a* (hue and chroma on a red-green scale), b* (hue and chroma on a yellow-blue scale) parameters for defining the color. The values for the three mentioned parameters can be calculated from the tristimulus X,Y and Z values (Fig. 4). In the color system CIE L*a*b*, the color difference ΔE* = [(ΔL*) 2 +(Δa*) 2 +(Δb*) 2 ] 1/2
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 3, 2012 55 ΔL*, Δa*, Δb* represents the differences between the CIE L*a*b* color parameter of 2 samples. Fig. 4 – Schematic representation of the CIE and Munsell color system after O’Brien. In Table 1 is presented the clinical color matching between dental structure and dental restorations, according to ΔE* values. Table 1 Color-matching tolerances by the clinical point of view after O’Brien The color difference ΔE* The clinical color matching between dental structure and dental restorations Color match by the clinical point of view 0 Clinically perfect 0.5…1 Clinically excellent 1…2 Clinically good 2…3.5 Clinically acceptable > 3.5 Clinically mismatch The color perception is sometimes a source of disagreement among the dentists, technicians and patients. There are different methods for color measurements: visual comparison using color standards such as Munsell color chips,color measurements made by using spectrophotometric or colorimetric methods [2]. Spectrophotometric measurements, done with spectrophotometers that measure the amount of light reflected at each wavelength, are used to evaluate the color parameters for porcelains, restorative resins, denture teeth, shade guides, and color modifications in dental materials. A double-beam spectrophotometer compares the responses from the object with a reference standard. From the spectral response can be calculated the color parameters for the object. Colorimetric measurements are done with colorimeters that measure the amount of light reflected at selected colors (eg. red, green, blue).
Page 1:
BULETINUL INSTITUTULUI POLITEHNIC D
Page 5:
BULETINUL INSTITUTULUI POLITEHNIC D
Page 8 and 9:
PETRU CÂRLESCU, VASILE DOBRE, IOAN
Page 10 and 11:
2 Niooleta Negoescu continue telle
Page 12 and 13: 4 Niooleta Negoescu min{ μ( Tu , T
Page 14 and 15: 6 Niooleta Negoescu Observation 8.
Page 16 and 17: 8 Ion Crăciun with large molecules
Page 18 and 19: 10 Ion Crăciun ∂ ∂ ∂ ∂ ∇
Page 20 and 21: 12 Ion Crăciun ⎧σ ji = ( μ+ α
Page 22 and 23: 14 Ion Crăciun If we introduce the
Page 24 and 25: 16 Ion Crăciun where the scalar La
Page 26 and 27: 18 Ion Crăciun and 0 0 0 2 2 ⎧
Page 28 and 29: 20 Ion Crăciun Ψ r Having assumed
Page 30 and 31: 22 Ion Crăciun Ignaczak, J., Tenso
Page 33 and 34: BULETINUL INSTITUTULUI POLITEHNIC D
Page 35 and 36: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 41: Bul. Inst. Polit. Iaşi, t. LVIII (
Page 44 and 45: 36 Radu Ibănescu and Cătălin Ung
Page 52 and 53: 44 Petronela Paraschiv case of biom
Page 54 and 55: 46 Petronela Paraschiv calculation
Page 56 and 57: 48 Petronela Paraschiv interpolate
Page 88 and 89: 80 Gelu Coman and Valeriu Damian ma
Page 90 and 91: 82 Gelu Coman and Valeriu Damian h
Page 92 and 93: 84 Gelu Coman and Valeriu Damian Th
Page 94 and 95: 86 Gelu Coman and Valeriu Damian iv
Page 96 and 97: 88 Florin Popa et al. In this figur
Page 98 and 99: 90 Florin Popa et al. the notations
Page 100 and 101: 92 Florin Popa et al. Δ = 0 and C
Page 114 and 115:
106 Vlad Marţian et al there is al
Page 116 and 117:
108 Vlad Marţian et al that all th
Page 118 and 119:
110 Vlad Marţian et al The battery
Page 120 and 121:
112 Vlad Marţian et al Current Int
Page 122 and 123:
114 Vlad Marţian et al Another fac
Page 124 and 125:
116 Vlad Marţian et al În concluz
Page 126 and 127:
118 Petru Cârlescu et al indicate
Page 128 and 129:
120 Petru Cârlescu et al hs p dT d
Page 130 and 131:
122 Petru Cârlescu et al air malt
Page 132 and 133:
124 Petru Cârlescu et al a b Fig.
Page 134:
126 Petru Cârlescu et al Iguaz A.,
show all

BULETINUL INSTITUTULUI POLITEHNIC DIN IAŞI

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?