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The purpose of this study was to investigate the color samples (A2, A3 and B1) of three different brands of resin composites using dentine masses. 135 discs were prepared (5 plates for each thickness, color and brand of composite material). A colorimetric evaluation, using white and black background, was performed just after preparation. The color was measured corresponding to “Vita” scale and ΔL, Δa, Δb and ΔE values were calculated using a spectrophotometer.The results showed that Value, Chroma and Hue often differ even if the same commercial color and same thickness is used. In conclusion, this study showed that the perfect aesthetics restoration is possible combining individual abilities, experience and correct techniques.
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Annali di stomatologia
aesthetic restoration
Benchmarking matching color in composite restorations
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Original Article
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2016
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Department of Oral and Maxillo Facial Sciences, School of Dentistry, “Sapienza” University of Rome, Italy
1971-1441
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aesthetic restoration
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Benchmarking matching color in composite restorations
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                                                                                                Original article



Benchmarking matching color in composite
restorations


Guido Migliau                                             tions are to obtain morphologic, optical, and biologic
Luca Piccoli                                              result miming natural enamel and dentine. This color
Laith Konstantinos Besharat                               matching is performed in order to obtain harmony
Umberto Romeo                                             with the surrounding anatomical structures.
                                                          Literature shows many analysis in fields like facial
                                                          aesthetic parameters (2), the influence of dental
Department of Oral and Maxillo Facial Sciences,           treatments on smile and of their proper relationship
School of Dentistry, “Sapienza” University of Rome,       between function and aesthetic (3), the color proper-
Italy                                                     ties of dental tissues (4) and (5) restorative materials
                                                          and the effectiveness of methods for assessing the
                                                          color (6, 7).
Corresponding author:                                     Our study focuses on the main element of restorative
Laith Konstantinos Besharat                               treatment: the composite resin.
Department of Oral and Maxillo-Facial Sciences,           The industry provides the operator with a wide range
School of Dentistry, “Sapienza” University of Rome        of composite resins to reproduce a certain color of Vi-
Via Caserta, 6                                            ta reference scale (8-10); for this reason, we tried to
00161 Roma, Italy                                         answer to the following question: can these materials
E-mail: besharatlk84@yahoo.it                             really provide the desired color?
                                                          Thus, we compared three different brands of compos-
                                                          ite resin and, using a spectrophotometer, analyzing
                                                          three basic parameters: Value, Chroma and Hue
Summary                                                   (11).

The purpose of this study was to investigate the
color samples (A2, A3 and B1) of three different          Materials and methods
brands of resin composites using dentine mass-
es.135 discs were prepared (5 plates for each
thickness, color and brand of composite materi-           Three different resin composites with dentine mass-
al). A colorimetric evaluation, using white and           es, colors A2, A3 and B1 were selected for in vitro
black background, was performed just after                study: Opallis (Isasan® srl, Italy), Artist (Pentron Clin-
preparation. The color was measured correspond-           ical®, USA) and Amelogen plus (Ultradent Prod-
ing to “Vita” scale and ΔL, Δa, Δb and ΔE values          ucts®, Inc, USA). The choice to work only with dentin
were calculated using a spectrophotometer.The             was dictated by the difficulty to overlap enamel and
results showed that Value, Chroma and Hue often           dentine known thickness plates, without the risk of
differ even if the same commercial color and              distorting the final chromatic results. Furthermore, it
same thickness is used. In conclusion, this study         is known that the readings provided by the spectrom-
showed that the perfect aesthetics restoration is         eter are greatly influenced by small air bubbles and
possible combining individual abilities, experi-          discontinuities in the composite mass (12). This can
ence and correct techniques.                              deflect the light emitted from the spectrometer distort-
                                                          ing the size and direction of the reflected light caus-
Key words: composite, color, aesthetic restora-           ing errors in numerical results (13). It was therefore
tion.                                                     necessary to realize discs with very smooth and pol-
                                                          ished surface, a condition difficult to satisfy. A metal
                                                          matrix was then used for the realization of composite
Introduction                                              platelets (discs), 1 cm thick and bearing along its en-
                                                          tire thickness holes of 1 mm diameter.
Resin composite is the material of choice used in di-     Metallic cylinders of 1 mm in diameter and height
rect restorations, as it offers an aesthetic, conserva-   ranging from 5 mm to 9 mm. For each hole fits close-
tive, durable and economic treatment solution (1).        ly for each hole (Fig. 1). It was possible, by including
The major requirement of composite resin is the abili-    several cylinders within the array, to modify the re-
ty to achieve an excellent color matching with the nat-   maining thickness of the matrix, obtaining known
ural teeth and the maintenance of the optical proper-     thickness (ex. if we introduce a 8 mm cylinder high in
ties over time. The goals for aesthetic dental restora-   the 1 cm deep hole, the final depth will be 2 mm).

Annali di Stomatologia 2016;VII (1-2): 29-37                                                                     29
     G. Migliau et al.


                                                                      laterally, causing only minimum increases in thick-
                                                                      ness (in the range of one tenth of a millimeter). The
                                                                      contact between glass plate and composite gener-
                                                                      ates a disc with smooth and glossy surface, suitable
                                                                      for subsequent spectrophotometric analysis (Fig. 3).
                                                                      Microscope slide allowed, due to its transparency, to
                                                                      the subsequent polymerization of the material by a
                                                                      halogen curing lamp (Elipar, 3M ESPE®) (Fig. 4).
                                                                      After polymerization, the slide was then carefully sep-
                                                                      arated from the plate and matrix, in order to minimize
                                                                      the distortion of the disc surface and the development
                                                                      of any microscopic defects that could skew the final
                                                                      results. Despite these precautions, however, has not
                                                                      been possible to avoid the separation of small frag-
                                                                      ments from composite plate margins. However, this
                                                                      does not affect the results of the experiment. This be-
                                                                      cause the spectrophotometer was able to zoom the
     Figure 1. Materials: metal matrix, metallic cylinders, a spat-   object examined and allows to select a precise spot
     ula and glass plate.
                                                                      for color analysis, avoiding areas of defects even
                                                                      when not visible at lower magnification.
                                                                      After removing the slide with a blunt screw placed in
     Thus, we used 1.5 mm, 2 mm and 2.5 mm thickness,
     using 7.5 mm, 8 mm and 8.5 mm height cylinders.
     Each cylinder was inserted into the hole of the array
     using a common hammer, adapting the two metal
     parts to each other.
     Furthermore, in the remaining depth of the hole of the
     matrix, composite was applied enough to fill the hole.
     This procedure was made using a composite spatula
     and in a single mass, in order to limit the possibility of
     air bubbles incorporation, resulting from the manual
     stratification of several layers (Fig. 2).
     Composite was then compressed against the cylinder
     by using a microscope slide (Thermo Scientific®,
     U.S.A.); a circular motion was imposed to the slide
     with constant pressure to remove air bubbles. With
     this technique, the exceeding material is displaced



                                                                      Figure 3. Glass plate application over the cylindrical metal
                                                                      matrix with exceeding material.




     Figure 2. The material was applied in the cylinder in the re-    Figure 4. The material was light-cured with a halogen
     maining depth.                                                   lamp.


     30                                                                                  Annali di Stomatologia 2016;VII (1-2): 29-37

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     Benchmarking matching color in composite restorations




     Figure 5. 135 plates, 45 of which are made with Opallis, 45 with Artiste and 45 with Amelogen Plus.


                                                                     It is important to underline that, with the help of a
                                                                     double and symmetrical light source, the results given
                                                                     by the equipment are in no way influenced by other
                                                                     sources of light.
                                                                     After calibration, the instrument was placed on a suit-
                                                                     able support to ensure that the angle between light
                                                                     beam and the surface of the discs remain constant
                                                                     (the Spectro Shade Micro was positioned with a 90°
                                                                     angle from the disc in order to generate an angle of
                                                                     45° between the two light beams and the disc itself),
     Figure 6. Discs performed over black background.
                                                                     then two digital images for each plate were made: the
                                                                     first on a black background (oral cavity), the other on
                                                                     a white background (tooth) (Figs. 6, 7).
                                                                     Each image is composed as follows: a zoomed pic-
                                                                     ture of the disc is showed on the left side, on the right
                                                                     its color distribution and below a table. This table in-
                                                                     cludes, from left to right, the details of Value, Chroma
                                                                     and Hue (or Value, quantity of red and yellow), the
                                                                     Vita scale for that color and thickness, and their nu-
                                                                     merical difference; on the right side there is a graphi-
     Figure 7. Discs performed over white background.                cal representation of this numerical difference; on the
                                                                     lower side ΔE is showed (ΔE = √ [(ΔL *) 2 + (Δa *) 2
                                                                     + (Δb *) 2]), expressing in mathematical terms how
     contact with the rear surface of the cylinder and with          much the overall color of the disc differs from its cor-
     the help of the hammer, the cylinder was slid through           responding Vita scale; beneath the ΔE are represent-
     the hole and the plate was separated from its sup-              ed visually, from left to right, the color of the disc, that
     port. Those procedures may in some cases crack the              corresponding Vita, and finally the two colors are rep-
     edges of the plate without influencing, as seen be-             resented side by side in order to reveal any differ-
     fore, the final analysis.                                       ences (Fig. 8).
     Thus, 5 plates for each thickness and for each color
     of each different brand of composite material were
     made. 135 plates were obtained, 45 was made with                Results and discussion
     Opallis, 45 with Artiste and another 45 with Amelo-
     gen Plus. From this pool of 45 plates, 5 were A2 to             Numerical values were then extrapolated from each
     1.5 mm, 5 A2 2 mm, 5 A2 to 2.5 mm, 5 A3 of 1.5 mm,              image and reorganized into three Tables. Table 1
     5 A3 of 2 mm, 5 A3 of 2.5 mm, 5 B1 of 1.5 mm, 5 B1              shows the analysis of 1.5 mm thickness composite
     of 2 mm and 5 B1 of 2.5 mm (Fig. 5).                            discs. Table 2 shows data on the 2 mm thickness
     The discs, grouped, packaged and labeled, were then             discs. Table 3 shows 2.5 mm thickness.
     sent to a professional technician who has selected              In each Table are shown from left to right, the name
     the chip that has lower defects from this pool of 5 for         of the composite used; the color of the background
     providing numerical data. This analysis was conduct-            used; the color printed on composite tubes; the Value
     ed using spectrophotometer (Spectro Shade Micro,                of the disc of the corresponding Vita scale and their
     MHT, Italy).                                                    difference; the Chroma of the disc of the correspond-

     Annali di Stomatologia 2016;VII (1-2): 29-37                                                                             31
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     G. Migliau et al.


                                                                                                    Figure 8. The disc color dif-
                                                                                                    ference according Vita
                                                                                                    scale.




     Table 1. The analysis of composite discs 1.5 mm thickness.

                                              L                         C                       H
     Composite           Background Color                                                                                 ∆E
                                              Tooth Vita      Diff.     Tooth Vita      Diff.   Tooth Vita        Diff.
                                      A3      74,82   73,28   1,54      27,89   22,78   5,1     76,84    85,98    -4,02 6,68
                         White        A2      76,42   75,6    0,82      27,41   18,87   8,54    80,04    87,92    3,12 9,13
                                      B1      86,3    77,76   8,54      16,6    12,77   3,84    96,61    92,64    1,01 9,41
     Amelogen Plus
                                      A3      69,03   72,98   -3,95     19,5    21,15   -1,64   84,71 84,63       0,03    4,34
                         Black        A2      70,86   75,98   -5,11     18,66   19,59   -0,93   91,32 85,99       1,78    5,49
                                      B1      77,43   77,84   -0,41     7,53    12,74   -5,21   111,24 93,17      3,07    6,07

                                      A3      74,9    73,36   1,54      31,95   22,48   9,47    79,93    85,83    -2,76 9,99
                         White        A2      78,21   75,84   2,37      31,18   19,2    11,98   80,27    87,02    -2,88 12,55
                                      B1      77,96   77,88   -0,25     23,89   13      10,89   84,65    92,55    -2,43 11,16
     Opallis
                                      A3      67,03   72,41   -5,38    22,57    21,9    0,67    86,76 84,89       0,72    5,47
                         Black        A2      70,04   75,96   -5,92    20,36    19,56   0,79    89,68 85,96       1,3     6,12
                                      B1      67,83   76,66   -8,83    12,2     13,74   -1,54   101,36 93,79      1,71    9,12

                                      A3      73,02   73,33   -0,31    33,67    21,93   11,74   77,52    85,8     -3,92 12,38
                         White        A2      77,17   75,77   1,39     31,11    18,94   12,17   79,92    86,69    -2,86 12,58
                                      B1      82,52   78,28   4,24     18,53    13,54   4,99    88,54    92,18    -1    6,63
     Artiste
                                      A3      63,25   72,64   -9,39    21,74    22,8    -1,06   84,31    84,62    0,12 9,45
                         Black        A2      67,19   76,27   -9,08    18,88    19      -0,11   85,26    87,41    -0,71 9,11
                                      B1      77,19   77,52   -0,33    13,31    13,31   0       97,17    94,15    0,49 0,59



     ing Vita scale and their difference, the Hue of the disc         Before examining the numerical data, is important to
     of the corresponding Vita scale and their difference;            focus directly on the images obtained by the comput-
     the ΔE.                                                          er software. In most cases there is an uneven distrib-

     32                                                                                 Annali di Stomatologia 2016;VII (1-2): 29-37

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     Benchmarking matching color in composite restorations


     Table 2. The analysis of composite discs of 2 mm thickness.

                                                    L                         C                       H
     Composite             Background Color                                                                                   ∆E
                                                    Tooth Vita      Diff.     Tooth Vita      Diff.   Tooth Vita      Diff.
                                          A3        72,84   73,46   -0,62     26,72   21,94   4,78    76,21   86,35   -4,28 6,45
                           White          A2        78,31   75,99   2,32      26,92   19,28   7,64    78,75   87,63   -3,53 8,73
                                          B1        84,5    77,8    6,7       18,29   13,42   4,87    94,62   92,73   0,52    8,3
     Amelogen Plus
                                          A3        72,04   72,18   -0,14     20,46   20,24   0,21    85,36   86,17   0,29    0,38
                           Black          A2        73,11   75,95   -2,84     19,26   19,23   0,03    88,02   86,52   0,5     2,88
                                          B1        80,05   78,27   1,78      9,53    13,47   -3,94   110,16 92,25    3,53    5,58

                                          A3        73,07   73,37   -0,3      31,32   21,7    9,63    78,79   85,81   -3,19 10,15
                           White          A2        77,13   75,83   1,03      30,75   18,89   11,86   78,66   87,51   -3,72 12,5
                                          B1        75,64   77,78   -2,14     22,12   12,73   9,39    82,62   91,81   -2,69 10
     Opallis
                                          A3        67,04   72,92   -5,89     22,72   21,17   1,55    86,01   85,98   0,01    6,09
                           Black          A2        70,36   74,86   -4,51     20,92   17,81   3,12    87,51   88,18   -0,22 5,48
                                          B1        70,66   77,66   -6,97     19,47   13,58   5,89    97,1    88,74   2,37    9,43

                                          A3        70,81   73,07   -2,26     33,03   21,39   11,64   75,75   86,52   -4,99 12,87
                           White          A2        76,31   75,47   0,84      31,08   18,51   12,57   77,45   87,37   -4,15 13,26
                                          B1        81,28   78,37   2,91      19,21   13,03   6,17    87,45   90,83   -0,93 6,89
     Artiste
                                          A3        63,81   73,16   -9,35     23,63   22,54   1,09    82,39   83,61   -0,49 9,42
                           Black          A2        68,89   76,05   -7,16     21,82   19,57   2,24    84,38   86,67   -0,82 7,55
                                          B1        77,94   78,31   -1,37     12,11   12,05   0,05    95,53   93,64   0,4     1,43




     ution of the material used (Fig. 8); only Amelogen                     It is interesting to note that background greatly influ-
     Plus in color B1 (Fig. 9) has an approximately uniform                 ence the color of the composite disc. The white back-
     color map. This issue is due in part to the manual lay-                ground, that simulate dentin (miming vestibular tooth
     ering and partly to excessive viscosity of the material.               face restoration at 1/3 cervical), reflects all the inci-


                                                                                                      Figure 9. Amelogen Plus (B1)
                                                                                                      uniform color map.




     Annali di Stomatologia 2016;VII (1-2): 29-37                                                                                    33
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     G. Migliau et al.


     Table 3. The analysis of composite discs of 2.5 mm thickness.

                                               L                         C                       H
     Composite           Background Color                                                                                  ∆E
                                               Tooth Vita      Diff.     Tooth Vita      Diff.   Tooth Vita        Diff.
                                       A3      72,22   73,07   -0,85     25,65   23,03   2,62    76,23    84,38    3,45    4,42
                         White         A2      77,82   74,74   3,08      26,55   17,86   8,69    78,77    87,96    -3,49 9,86
                                       B1      85,25   78,16   7,09      18,1    13,29   4,81    94,27    89,26    1,36    8,68
     Amelogen Plus
                                       A3      69,31   72,88   -3,57     21,62   21,25   0,37    83,36    85,59    -0,84 3,68
                         Black         A2      74,18   75,97   -1,78     20,73   20,1    0,63    86,96    86,53    0,15    1,9
                                       B1      79,6    77,99   1,61      11,71   13,03   -1,32   104,83 92,46      2,66    3,38

                                       A3      71,87   73,23   -1,37     29,54   22,47   7,07    78,12    83,98    -2,63 7,66
                         White         A2      75,89   76,21   -0,33     28,92   18,84   10,08   77,33    87,35    -4,07 10,88
                                       B1      74,99   77,86   -2,88     22,61   12,79   9,81    83,93    93,19    -2,75 10,59
     Opallis
                                       A3      68,32   72,99   -4,67     23,78   20,93   -2,84   85,34    86,15    0,32    5,48
                         Black         A2      71,07   74,46   -3,39     21,69   18,65   3,04    85,28    88,01    0,96    4,65
                                       B1      70,03   78      -7,98     15,67   12,92   2,75    90,59    91,77    -0,29 8,44

                                       A3      69,52   73,38   -3,86     31,97   21,82   10,15   73,96    85,97    -5,53 12,19
                         White         A2      76,08   75,98   0,1       32,1    19,07   13,03   75,96    87,23    -4,86 13,91
                                       B1      80,83   77,99   2,84      18,86   13,53   5,34    84,98    91,52    -1,82 6,31
     Artiste
                                       A3      63,44   72,98   -9,53     23,25   20,95   2,3     78,29    86,09    -3      10,26
                         Black         A2      69.81   75,99   -6,19     23,03   18,48   4,45    83,44    86,6     -1,14 7,76
                                       B1      75,43   77,95   -2,52     13,07   12,98   0,09    92,19    92,38    -0,04 2,52




     dent light; the black background simulate a restora-
     tion with the oral cavity as background (for example
     fractured incisal angles restoration), will absorb all
     the light directed on it. These differences in absorp-
     tion would certainly influence the overall color of the
     restoration in terms of Value and Chroma, which
     would be much higher if the composite is placed on a
     white background rather than on a black one. Con-
     trariwise, Hue increase on black background if com-
     pared to white.
     It is important to observe that white and black repre-
     sent only two extremes of colors that can be found as
     background during restorations in the oral cavity.                Figure 10. Value decreases with increasing thickness over
                                                                       a white background.
     Value

     Analyzing the results for what concerns the Value of              trophotometer analysis due to limitations in the manu-
     the composite (L) we can see that, on a white back-               al technique, even if standardized, and to the exces-
     ground (7 samples out of 9) normally L decreases                  sive viscosity of the material.
     with increasing thickness (Fig. 10); this shows that in-          On a black background L is significantly reduced if
     creasing the thickness and thus the opacity, compos-              compared with white background; this because black
     ite is less influenced by the background which en-                absorbs and reflects light, appearing darker to an ob-
     hances its Value making it brighter. Only in 2 samples            server.
     this is not shown (Amelogen A2-B1). However, A2                   Furthermore, the samples of 1.5 mm thickness are al-
     plate with 1.5 mm thickness and B1 of 2.5 mm, dis-                ways the darkest (except for Artiste B1, where the 2.5
     plays surface defects that may have influenced spec-              mm sample is the darkest, probably due to an error

     34                                                                                  Annali di Stomatologia 2016;VII (1-2): 29-37

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     Benchmarking matching color in composite restorations




     Figure 11. Value is significantly reduced over a black back-   Figure 12. Chroma tends to decrease over the white back-
     ground.                                                        ground.

     during stratification), while 2 mm and 2.5 mm sam-
     ples, present in most cases (6 times out of 9) small
     differences in Value that are imperceptible to seen
     (Fig. 11); clinical trials have shown that the human
     eye cannot distinguish ΔL of -1 <x> 1. A trained and
     experienced eye can refers ΔL of -0.05 <x> 0.05.
     This data shows a substantial difference in L value
     between composites with same color and thickness
     but from different manufacturer: the Amelogen B1 is
     brighter than B1 from other 2 brands.
     Regarding ΔL on a white background, we noticed that
     10 samples out of 27 show good correspondence
     with Vita scale (difference -1 <x> 1), 12 are brighter         Figure 13. Chroma increases with the thickness over black
     and 5 darker than baseline color. Analyzing each               background.
     manufacturer we observe that AMP, for example, in
     A3 2 mm and 2.5 mm cover well the background and               OP, already perceived dark as we have seen on
     has a good correspondence with Vita scale; with 1.5            white background, shows low Value; we noticed the
     mm thickness is strongly influenced by the back-               same effects for ART A3 and A2. ART B1 at 1.5 mm
     ground and appear brighter. Contrariwise AMP A2 is             thickness, result to be similar in L to Vita scale,
     influenced from the background, showing an accept-             whereas at 2 mm and 2.5 mm, covering black back-
     able ΔL at 1.5 mm, but appears too bright in 2 mm              ground, it is obviously brighter.
     and 2.5 mm thickness. This inconstant chromatic be-
     havior with different thickness could be explained by          Croma
     the defects during stratification mentioned above.
     AMP B1 is always very bright with white background             On a white background we observed that Croma (C)
     at all thickness.                                              decrease with increasing thickness, This occurs be-
     Opallis (OP) A3 at 1.5 mm and 2 mm thickness,                  cause, reducing thickness, the composite is more in-
     shows higher ΔL than Vita, but at 2.5 mm it is no              fluenced by the background that reflects light, caus-
     longer influenced by the underlying background, ap-            ing an increasingin saturation (Fig. 12).
     pearing darker. OP A2 behaves as OP A3, showing                This behavior is followed by 5 samples out of 9. In
     an acceptable Value matching even at 2.5 mm. OP                other cases the differences between discs regarding
     B1 displays acceptable ΔL at 1.5 mm, but appears               Croma, are almost imperceptible; clinical studies
     darker at 2 mm and 2.5 mm.                                     have shown that a ΔC of -3 <x> 3 is not distinguish-
     Artiste (ART) A3 shows same behavior like OP B1 in             able to the untrained human eye. Furthermore, in 7
     terms of ΔL. ART A2 is very bright to 1.5 mm, where-           samples out of 9, the thinner ones reveal more in-
     as at 2 mm and 2.5 mm displays correct ΔL. ART B1              tense color.
     is always too bright. Regarding ΔL on a black back-            On a black background C is greatly reduced; this be-
     ground, we noticed that only 3 samples out of 27               cause black background absorbs light, and therefore
     show good correspondence with Vita scale (differ-              the color. Consequently, the saturation is reduced
     ence -1 <x> 1), 22 are Darker and 2 brighter than              too. Normally, C value should increase with the thick-
     baseline color. AMP A3 is too dark except at 2 mm,             ness, being the samples less influenced by the back-
     where matches perfectly. AMP A2 is always too dark             ground. This happens for 6 samples out of 9; in the
     even if, increasing the thickness, the background has          remaining 3, 2 of them have subtle differences. The
     lesser influence in ΔL. AMP B1 at 1.5 mm, appears              other 1, OP B1 and 2 mm thickness, differs from the
     very similar to Vita scale; at 2 mm and 2.5 mm, cov-           previous due to some small surface defects that
     ering the background, shows an increase in ΔL. The             could modify C value (Fig. 13).

     Annali di Stomatologia 2016;VII (1-2): 29-37                                                                         35
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     G. Migliau et al.


                                                                                         Figure 14. The tool shows nu-
                                                                                         merical and visual feedback of
                                                                                         color variations.




     By an examination of values showed in Tables 1-3         our samples is the hue (H). Observing the values of H
     we can assess that for the same commercial color         taken from discs lying on a white and a black back-
     and thickness, the three different brands of composite   ground, it is not difficult to understand how this ap-
     show different characteristics regarding Croma.          proach can influence our color perception: clinical tri-
     Analyzing the values of ΔC expressed by the com-         als show that the vast majority of the population is
     posites on the white background, we noted that 26        unable to perceive ΔH of -5 <x> 5.
     samples out of 27 show an excess in saturation than      The Hue is an intrinsic component of the material
     the Vita scale. Only one disc displays C values that     generally well represented. Just in one case H devi-
     match the corresponding Vita (AMP A3 2.5 mm thick-       ates significantly from the Vita value, showing a slight
     ness).                                                   tendency to red; note also that there is a good corre-
     Examining ΔC we noted that in 21 samples out of 27       spondence between the discs of same thickness and
     the black background reduce the C value so as to         color and of different manufacturer. Thus, H, com-
     bring them near to Vita scale baseline; 4 samples        pared to L and C is less influenced by the back-
     shows a too much intense color whereas the remain-       ground color.
     ing 2 appears above board.
     Focusing on each composite manufacturer we noted
     that AMP A3 shows C slightly weaker at 1.5 mm (in-       Conclusions
     fluenced by the black background), but is almost per-
     fect at 2 mm and 2.5 mm. AMP A2 is always superim-       Identification of color is the first issue to deal with.
     posed on Vita scale. AMP B1 at 1.5 mm has low C          The picture provided by the spectrometer, shows how
     value, it is also above board at 2 mm, whereas at 2.5    the tooth color is far from being homogeneous.
     mm covers the black background showing a C corre-        Furthermore this color map can be used for aesthet-
     sponding to Vita scale. Furthermore OP A3 1.5 mm,        ics reconstruction of the anterior sector (Fig. 14).
     attenuated by the background, matches color perfect-     The second issue is choosing the most suitable com-
     ly. At greater thickness, Croma differs from Vita, but   posite for restoration. A solution should be using a
     remains appropriate. OP A2 at 1.5 mm is acceptable,      brighter dentin if we working with a single mass, or to
     slightly intense at 2 mm and 2.5 mm (less influenced     superimpose a white enamel if we work on two mass-
     by the fund). OP B1 presents low ΔC to 1.5 mm, is        es. Regarding Croma, however, the most composit
     more intense at 2.5 mm, whereas at 2 mm has high C       examined shows an excessive color intensity: even in
     value due to small imperfections (as mentioned be-       this case will be sufficient to use a dentin of above-
     fore). ART A3 has a C superimposed to Vita scale on      board color or to superimpose an enamel that would
     black background for all samples. ART A2 has a low       mitigate the C. Generally, the Hue is not a problem,
     ΔC at 1.5 mm but too saturated at 2 mm and 2.5 mm.       because is not able to modify the general chromatic
     ART B1 is almost perfect in terms of ΔC for all sam-     effect (14).
     ples.                                                    A third issue comes from problems in the layering tech-
                                                              nique. The study shows how, almost in whole samples,
     Hue                                                      the color distribution is not uniform. In fact the computer
                                                              images show a patchy color map, underlining how the
     The third and last parameter that defines the color of   color differs from what we expect (Fig. 15).

     36                                                                         Annali di Stomatologia 2016;VII (1-2): 29-37

Copyright © 2016 CIC Edizioni Internazionali Unauthorized reproduction of this article is prohibited.
     Benchmarking matching color in composite restorations


                                                                                                           Figure 15. The spectropho-
                                                                                                           tometer color analysis shows
                                                                                                           that color is not uniform.




     Composites from different brands can be slightly                            resin composites and other conservative esthetic procedures.
     brighter or darker when compared, slightly more or                          Eur J Esthet Dent. 2008 Spring;3(1):14-29.
     less opaque than the underlying background, more or                   4.    Yu B, Ahn JS, Lee YK. Measurement of translucency of tooth
                                                                                 enamel and dentin. Acta Odontol Scand. 2009 Feb;67(1):57-64.
     less intense in color, but generally show similar be-
                                                                           5.    Kim SJ, Son HH, Cho BH, Lee IB, Um CM. Translucency and
     havior when used during clinical practice. Thus, it is
                                                                                 masking ability of various opaque-shade composite resins.
     important to choose the correct composite in relation                       J Dent. 2009 Feb;37(2):102-7. Epub 2008 Nov 22.
     to the background used and be able to recognize                       6.    Kuzmanović D, Lyons KM. Tooth shade selection using a col-
     when to apply a different composite layers, enamel or                       orimetric instrument compared with that using a conventional
     dentin, in order to adjust effects or excesses in L                         shade guide. N Z Dent J. 2009 Dec;105(4):131-4.
     and/or C values. We also emphasize that, even in                      7.    Judeh A, Al-Wahadni A. A comparison between conventional
     this case, spectrophotometry can meet the needs of                          visual and spectrophotometric methods for shade selection.
     the neophyte, guiding the management of any adjust-                         Quintessence Int. 2009 Oct;40(9):e69-79.
                                                                           8.    Magne Bruzi G, Carvalho AO, Giannini M, Maia HP. Eval-
     ments in color choosing.
                                                                                 uation of an anatomic dual laminate composite resin shade
     In conclusion, we can assess that, although the most                        guide. J Dent. 2013 Aug;41 Suppl 3:e80-6.
     recent restoration materials offer a greater range of                 9.    Park SK, Lee YK. Shade distribution of commercial resin com-
     colors, although the color properties of these materi-                      posites and color difference with shade guide tabs. Am J Dent.
     als are similar to the dental tissues, as our study                         2007 Oct;20(5):335-9.
     shows, the realization of a perfect aesthetic restora-                10.   Paravina RD, Kimura M, Powers JM. Color compatibility of
     tion is possible only where a certain individual manu-                      resin composites of identical shade designation. Quintessence
     al dexterity joins the experience and acquisition of                        Int. 2006 Oct;37(9):713-9.
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                                                                           12.   Chirdon WM, O’Brien WJ, Robertson RE. Mechanisms of go-
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     Annali di Stomatologia 2016;VII (1-2): 29-37                                                                                             37
Copyright © 2016 CIC Edizioni Internazionali Unauthorized reproduction of this article is prohibited.
