Shade characteristics of natural teeth

Shade characteristics of natural teeth
Natural teeth demonstrate a surprising amount of
shade characteristics, which are mostly formed
spontaneously in the enamel. Unfortunately, a dental
laboratory material with such characteristics is not
available. Therefore, we have to develop each
characteristic individually using differently shaded
materials, which are layered in a specific way to create
optical effects that are similar to those of natural
dentin. To achieve sound integration of a metal ceramic
crown, it is necessary to fabricate a core that favours
light transmission. The following images show a
comprehensible example of this concept.
The marginal area should favour the light
transmission between natural teeth, crown
and soft tissue.
The best method to achieve
sound integration is to create
a translucent core.
1

A metal core will always work against us, because it will block
light transmission thus creating dark areas in the internal layers
of the teeth, which results in a higher opacity in the exterior
layers of the crown.
If a metal core has to be used, it is imperative to create a
ceramic shoulder. The picture clearly illustrates how the metal
substructure is blocking the light, while the light passes freely
through the other areas until it reaches the preparation, thus
creating a soft transition area that favours the integration of
the restoration.
In this Special Edition, we will identify
the different shade characteristics that
are present in natural teeth and explain
a step-by-step procedure to reproduce
these characteristics using ceramic
materials.
2

White, orange and brown enamel cracks
We can observe this shade characteristic quite frequently in
the dental enamel of adjoining teeth. The shade and
appearance of enamel cracks vary. While the shade variation
does not present that much of a
problem, its influence on the
appearance of the restoration
appears to be more of a difficulty.
The appearance of an enamel
crack or fissure changes in
response to the light refraction
angle. In other words, if an enamel
crack is exposed to frontal light, it
Fig. 1a
looks like a fine, clearly defined line (Fig. 1a). If, in contrast,
the enamel crack is exposed to lateral light, light refraction is
more pronounced (Fig. 1b). Virtually all natural enamel cracks
Fig. 1b
are located in the enamel. Therefore, the corresponding
shade characteristic of a restoration should be created in the
same area, i.e. in the final layer of the layering pattern, when
the underlying layers have already
been covered with a translucent
material. It is very important to
use the entire thickness of the
translucent layer to reproduce the
fissure, since this will provide it
with a three-dimensional, true-tonature
appearance. If we limit ourselves
to staining only the intermediate
layers, the enamel crack will demonstrate a twodimensional
appearance and thus not correspond to the
natural model.
The enamel crack is created after the internal layering has
been built up to the point at which only the translucent
material has to be applied to complete the morphology. At
this stage, the dentin, incisal and other shade characteristics
have already been built up.
The next step is to build up the morphology of the tooth
using Transpa neutral. The layer should extend to the area
where the enamel crack is to be placed.
3

Transpa neutral is applied here to build up a wall outlining
the future morphology of the fissure. This wall has to be as
perpendicular as possible to the surface of the basic build-up.
If the angle is enlarged, a frontal view would show a gap
rather than a delicate crack.
Now a thin line is applied to the wall using a brush dipped
into Stains Crack Liner. It is important that Transpa neutral is
still humid when the characterization is applied. Otherwise
the Crack Liner would be quickly absorbed by the Transpa
neutral material and, as a result, the crack would be too
pronounced.
Now the morphology of the crown is completed using
Transpa neutral. Applying the translucent material carefully is
very important to prevent the materials from moving and thus
compromising the outline of the fissure.
Transpa neutral is applied up to the location of the next crack
and the crack is again built up as described above.
4

Here, however, the crack is created using pure dentin
material. For this purpose, the brush is dipped into the dentin
material and the characterization is applied to the area that
has previously been prepared with Transpa neutral. Cracks
that have been created with dentin material look softer and
refract less light than cracks created with Crack Liner.
Another way of developing a crack is to carve a small groove
into the ceramic material using a spatula after the layering
has been completed. However, this technique is usually
applied for more rectilinear cracks, since it is very difficult to
define the crack's course using a spatula. This groove should
extend down to the opaquer.
After the groove has been applied, one of the walls is stained
in the desired shade. In this case orange is used, which has
been slightly diluted with a small amount of glazing paste.
Glazing paste is preferable to a liquid to prevent the pigments
from excessively penetrating the ceramic material. Once the
stains have been applied and the ceramic material has slightly
set, the two sides of the groove are pushed together and the
morphology of the tooth is completed.
5

Appearance of the restoration after firing.
After the crown has been polished and glazed, we can
examine the final appearance of the fissures. In the picture
the tooth is exposed to lateral light, namely to light coming
from the mesial. Now we can see the exceptional behaviour
of Crack Liner. The mesial part of the crack is much more
saturated than the distal part, as the crack blocks the light in
the same way as the enamel of natural teeth does.
If we examine the enamel
cracks in back light, we can
clearly see how the cracks
efficiently block the light.
6

The same technique can
be applied to create more
pronounced cracks with
infiltrations.
However, purer pigments or
more intensive shades such
as brown, as was applied in
this case, are used.
After the stains have been applied, the enamel crack is
completed using Transpa neutral, as described above.
The final result.
7

Clear areas
This characteristic is found to a lesser or higher degree in
99 % of all natural teeth. Therefore, creating it should be
regarded as an additional stage of the layering procedure
rather than part of the shade characterization procedure.
Usually, the characteristic appears as a clear area in the
enamel or dentin. In some cases, however, it is more
pronounced, looking like a stain caused by decalcification.
Basically, we could integrate this shade characteristic into the
first dentin layers of the build-up. A saturated white dentin
material could be used to create the desired shade effect. The
disadvantage of this approach, however, is that any error
regarding the location of the characterization or selection
of shade cannot be corrected without having to redo the
entire layering. It is therefore advisable to include this shade
characteristic in the final layer, which is easy to access.
However, if the brightness of an area in the final layer is
manipulated, the opacity of this area will also increase. In
other words, we would lose translucency in the area of the
shade characteristic. For this reason, the characteristic in
question should be incorporated into an intermediate layer.
In this case, we will design a stripe-shaped bright area. For
this purpose, we will use a whitish translucent material, such
as Effect Material 2 from the Impulse 1 Kit. For accurate
visual control, the ceramic material has been dyed yellow.
All we have to do is to apply a small amount of Effect
Material 2 on that area of the dentin material where the
shade characteristic is to be
located. The intensity of
this shade characteristic is
regulated with the thickness of
the ceramic layer. If a more
pronounced characterization is
required, a more translucent
material with a higher degree of
saturation is used, such as Effect
Material 3, rather than applying a
thicker layer of Effect Material 2.
This shade characteristic is
applied on top of the basic
layering. In this case, the
dentin, incisal, and shade
characteristics of the incisal edge
have already been applied.
In addition, a decalcification spot in the distal margin of
the incisal edge will be created. For this purpose, a highly
saturated translucent white
material is applied, such as
Effect Material 4 from the
Impulse 1 Kit. As the desired
characterization should be very
pronounced, we will try to
reproduce it with an intermediate
layer and a final layer. In this way,
light can reach the Effect material,
thus creating a pronounced
characterization.
8

The tooth morphology is
now completed using
Transpa neutral. The area to
which Effect Material 4 has
been applied should not be
covered.
Appearance of the
restoration after firing.
After polishing and glazing, the two characterizations are clearly visible.
9

Opalescent incisal edge
Highly opalescent incisal edges are very common in young
teeth. Reproducing this characteristic is difficult, but not
impossible. The opalescence results in a concentration of light
in the incisal edge, which is also known as incisal halo. The
incisal halo in a natural tooth is a spontaneous occurrence,
due to the special light refraction in dental enamel. Unfortunately,
the opalescent materials do not refract the light as
intensely as natural enamel. Therefore, we have to use
pigmented materials to reproduce the incisal halo.
Immediately after the translucent area of the opalescent
edge has been reproduced,
the incisal halo is
created using Incisal
Edge, a material
that has been
especially developed
for this purpose.
Again, this material
should be allowed to
mix with the previously applied Effect Material 1.
For this shade characterization, the incisal edge of the
completed build-up has
to be reduced
following the
pattern of the
previously designed
mamelons, which
are then covered
with transparent
material up to the
reduced area.
Next, Effect Material
1 from the Impulse
1 Kit is applied. It is
important that this
material does not
excessively mix with
the materials of the
build-up.
The opalescent incisal edge and the appearance of the incisal
halo are clearly visible immediately after application.
10

Abrasion of the incisal edge
Abrasion is the wear of the incisal edge (mostly the palatal
area) caused by natural functions. If abrasion is present in the
enamel, the morphology of the tooth is altered, together
with the shade in the area of the abrasion. The latter
occurrence is quite obvious, as abrasion causes a loss in
enamel and exposes the dentin. Moreover, these areas often
show signs of infiltration resulting in areas that demonstrate
pronounced pigmentation.
In this case, we will create a wear pattern using a highly
saturated shade.
Next, Occlusal Dentin brown and Occlusal Dentin orange are
mixed in a 1:1 ratio. A small quantity of white stains is added
to the mixture to render
it slightly opaque. This
mixture is used to fill the
entire groove of the wear
pattern to give it the
appearance of internal dentin
that has filtered between the enamel and dentin.
This characteristic is reproduced
after the crown has been
completely layered. Once
the palatal area has been
contoured, a groove in
the form of the intended
wear pattern is created
using a spatula.
If the wear pattern should appear less aggressive, the 1:1
mixture of Occlusal Dentin
brown and orange can be
substituted by dentin
material to which a small
amount of dentin-coloured
Shade material has been
added to heighten the
degree of saturation. The intensity can be regulated by the
amount of Shade used.
The wall of the groove is
now stained using Crack
Liner to block out the light
in this area. Additionally,
some white stains may be applied. In this case, the stains
were applied to the distal area of the wear pattern.
Another more intensive shade,
such as in this case brown,
may be applied to the bottom
of the groove and to a
wall of the wear pattern.
Orange or khaki are yet
other possibilities.
11

Mamelons in the incisal edge
This shade characteristic is mostly evident in young teeth.
However, the characteristic is maintained even in mature
teeth. Consequently, mamelons are outlined in most
restorations, even if they are not evident at the time of shade
determination. Mamelons cause the incisal edge to appear
richer, which will favour the integration of the restoration
into the oral environment. If the mamelon shade has not
been determined by the dentist, it is advisable to use a somewhat
subdued shade, such as the salmon-coloured mamelon
material of the Impulse Kit.
For best results, the underlying material and the mamelon
material should be slightly moist during application, as the
pigments of the two materials may then slightly mix thus
creating a soft transition area.
Next, Transpa blue of the
Impulse 1 Kit is applied to
this area.
Then, small grooves are carved
into the incisal edge by means
of a brush.
The salmon-coloured mamelon
material is applied to the basic
build-up consisting of dentin
and incisal material.
These grooves are filled with
an opalescent material, such
as Effect Material 1 of the
Impulse 1 Kit.
In a first step, the mesial and
distal angle of the incisal edge
are slightly reduced.
Using the desired mamelon material, in this case salmon,
wedge-shaped lines that are thinning out towards the incisal
edge are drawn, with the wider
area in the center of the
mamelon. Usually, three
mamelons are present in
natural teeth. However, the
number of mamelons is unimportant.
Consequently, four or five mamelons may be
created.
12

If the mamelons need to be more
pronounced, a small quantity
of Brilliant Dentin may be
applied. Given the opacity of
this material, only a trace of it is
required.
Finally, the incisal edge is
completed by applying a layer
of Transpa neutral. We have to
be keep in mind that the more
Transpa neutral is applied, the
less pronounced the shade
characterization will be.
Completed crown.
13

Areas of light absorption
Natural teeth often demonstrate horizontal stripes that
appear grey. This characteristic is reproduced in the dentin.
Next, the grooves are filled
using Transpa neutral.
The basic build-up has to be
completed before this characteristic
is designed.
After the grooves have been
filled, the tooth morphology is
completed in the usual manner
using Transpa neutral.
In this case, two short, horizontal stripes will be created. For
this purpose, two grooves are
drawn on the surface
using the tip of the
brush. It is important
that the grooves do not
demonstrate perpendicular
walls. Otherwise
the characterization will be
too pronounced.
The completed restoration: The horizontal stripes made of
pure Transpa neutral absorb more light and thus appear grey.
14

Shade characteristics of our patients
Whenever we look at the shade of
the permanent teeth of our patients,
we can observe specific shade
characteristics. The intensity of these
characteristics may vary from case to
case, but they are present in each
patient. These shade characteristics
must be maintained when
fabricating anterior restorations in
particular. If only a single anterior
crown is required, the shade
characteristics of the remaining teeth
have to be taken into consideration.
If all the anterior teeth are replaced,
however, dental technicians have
much more creative freedom in the
fabrication of the individual buildups.
Younger teeth always
demonstrate increased
brightness and translucency
due to their high
opalescence.
The opalescent area and
the incisal halo of this
restoration were designed as
described above (clinical
case of the Dr. Erika Téllez).
Moreover, pronounced
shade characteristics may
be found in very young
teeth. Decalcified areas and
areas of light absorption
frequently appear
together (clinical case of
Dr. Oriol Llena).
15

Clinical preparation
Several shade characteristics
may occur at the same time.
In this case, a complicated
layering procedure was
required to obtain optimum
results (clinical case of
Dr. Oriol Llena).
Here, two crowns for teeth
11 and 12 were fabricated.
The two lateral anteriors,
whose dentin areas are very
different from each other,
were used as a reference.
The challenge was to create
two restorations that would
enhance the patient’s look
while simultaneously
matching the lateral
incisors (clinical case of
Dr. Oriol Llena).
16

When an entire anterior group of teeth is restored, the room
for creativity is larger as the dental team may design the
shade characteristics according to their preferences.
In this case, the entire anterior region from canine to
canine was restored with d.SIGN veneers (clinical case of
Dr. Eduardo Anitua).
17

I would like to round off this presentation by providing an overview
of the impressive range of possibilities that IPS d.SIGN offers, using
the case studies below as examples.
Oral situation before treatment.
The image of the patient’s smile is the image of our work.
By examining the crowns closely, we realize how important
the shade characteristics are to imitate the natural tooth.
18

Initial situation before treatment.
Situation after the treatment has been completed.
Detail image of IPS d.SIGN restorations.
19

Clinical case of Dr. Erika Téllez, showing an IPS d.SIGN veneer on tooth 12, an IPS Empress crown on tooth 11 and 21 and an
IPS d.SIGN metal crown on tooth 22.
20

Crown after having been cemented in place.
21

*Material taken out from the book
"Sombras, un mundo de color"
August Bruguera
C/Vialmari, 56 local 1
Barcelona 08015
Spain
bruguera.lab@infomed.es
22

Descriptions and data constitute no warranty of
attributes and are not binding.
Printed in Liechtenstein © Ivoclar Vivadent AG
575240/0503/2/e/BVD

d.SIGN ®
Special Edition
IPS
A. Bruguera