Luca Martinelli
The rubber dam technique - Tools used
Publication no. 8 - 06 November 2012
1. THE TECHNIQUE OF THE DAM
1.1 INTENDED USE
The dental dam, designed in the U.S. in 1864
by Dr. Sanford Christie Barnum, is used to keep dry the tooth on which the conservative
treatment must be carried out.
Sanford Christie Barnum
(1838-1885)
To date, there are no normative references,
however, the following standards are developing
- ISO 16635-1 Dentistry - Rubber Dam
Technique - Part 1: Rubber Dam Punch and standards;
- ISO 16635-2 Dentistry - Rubber Dam
Technique - Part 2: Rubber Dam Clamp Forceps.
The
dentists who use the dam are not many, although in recent years their number is
increasing.
This operating mode has many advantages that
are, but not limited to:
1 - Perfectly dry operative filed, and
therefore free from blood, saliva, etc..;
2 - Operative filed with reduced risk of
microbial contamination;
3 - Operative field with greater
accessibility;
4 - Operative field with greater visibility;
5 - Operative field with reduced risk for the
patient of ingestion of materials and liquids;
6 - Increased ability to perform the work non
only technically correct, but also aesthetically pleasing;
7 - Safety level for operators against
cross-contamination;
8 - Increased legal safety level, since the
use of the dam allows greater attention to risk and thus helps to prevent the
accident.
Added
to this is a considerable saving of time; if one considers that all the
activities such as the suction, the drying, the application of cotton rolls,
rinsing the mouth of the patient etc.. are not necessary, it is easy to
understand how its use can result in savings almost half of the time required
to perform the same work without dam.
All
this gives then a better comfort to the patient and less stress for the entire
dental team.
The dam is used with various tools and
accessories that are:
- The dam;
- The punch;
- The hook holder and
- The hooks.
There are then some accessories such as a
template to mark the points on which then make the holes, tool mainly used by
beginners, and a water-soluble lubricant that can be used to easily insert the
dam in the interproximal spaces between the teeth.
1.2 The
dam and its variants
The
dam consists a sheet of "rubber" large on average 15 x 15 cm, with
thickness that can be understood, approximately, between 0.14 and 0.38 mm (Fig.
1), consider that on the market there are several shapes, including
rectangular, of different thickness, with right angles or chamfers.
They may be coloured
(E.g.green, grey, blue, lilac, etc..), the colours identify different
thickness, but varies from manufacturer to manufacturer, they may be flavoured
(E.g mint, vanilla ...).
Fig. 1
1.3
Assembly of the dam
Before using the dam
it must be put on a support, the frame (Fig. 2) that will allow to keep it in
an extended position, in the mouth of the patient, i.e. without it
"collapsing" and therefore without losing its insulating function.
Fig. 2
Example
of frame with dam during assembly
Subsequently the dam
must be perforated, there are methods that may also provide for the use of a
template with a special punch (Fig. 3) to allow to let pass outside the tooth
requiring the treatment (Fig. 4).
Fig. 3
Fig. 4
Piercing can also be
done using a template (Fig.5).
Fig. 5
Example
of some templates for piercing the dam
To steady the dam on
the tooth, and then allow it to perform its insulating function, a hook is used
(Fig. 6), a kind of clip which is fixed on the tooth through a clamp specially
made for this purpose (Fig. 7).
Fig.6
Fig. 7
To prevent
aspiration, or swallow, before its insertion the hook is usually anchored to a
dental floss cut and left very long (Fig. 8).
Fig. 8
Example
of anchored hook: in this picture the operator has used retraction cord instead
of dental floss.
This system is called "Parachute" although
nothing has to do, as a structure, with the parachute used in endodontics.
There are several
procedural techniques for inserting the dam on the tooth of the patient:
1 - First the hook
then the dam;
2 - First the dam
then the hook;
3 - Dam and hook
together;
4 - Hook dam and
parachute together,
in fact tools are
exactly the same, only their use time sequence varies.
1.4.
Constituent material
The dam is generally
made of latex, however, because of the allergenic problems that may arise from
the presence of the latex, it is also made of high resistance, latex-free
rubber (E.g. Polyisoprene/Plastomers) and free of dust, in some versions it can
even be autoclaved.
2.
THE FRAME (Young frame)
The frame is used to
keep the dam stretched so that it can be effectively put on the tooth.
There are several
shapes of frame, made of metal (Fig. 9-10), usually the average size results in
a square of about 15x15 cm.
At the sides of the
frame there are small pins which serve for fastening of the dam, in some of
these frames, (Fig. 10) on the ends of the stems, are some "buttons"
that serve to anchor the wires in case of cervical ligatures.
Fig. 9
Fig. 10
Examples
of some metal frames
There are also frames
in plastic material (Fig. 11) whose main advantage is the radiolucency.
Fig. 11
Example
of some frames in plastic material
In reality both
models and constituent materials are many; some tools consist for example of a
frame-hook suitable for "mini dams", such as the "Magic
Clamps" (Fig. 12) which can be used for only a few teeth and only for the
lower ones, and so many other systems meant to make use of the dam simpler and
more immediate; however please note that those who know how to use the
"traditional" dam hardly leaves for different systems.
Fig. 12
Magic
clamp
2.1
Constituent material
Usually the metal
frames are made of stainless steel AISI 420 - 410.
The frames made of
plastic in principle are made of polypropylene, or other polymers, more
resistant, that allow the heat-steam sterilization.
3.
THE PUNCH
The punch serves to cut the hole in the sheet of latex,
or rubber, that will allow the tooth to pass.
One of the main feature of the punch is that of piercing
in a net and easy way, unlike the dam may break during the insertion phase,
with obvious consequences.
Also in this case we
have several models of punches (Fig. 13) although the most known and used are
two or three.
Fig. 13
Example
of some punches
3.1.
Constituent material
The punches are
generally made of stainless steel AISI 420 or 410.
Parts such as
springs, pins etc.. may be made of AISI 301, 303, 304, 316 or 430, depending on
the constructional requirements.
4.
HOOK HOLDER CLAMP
They are used to
insert and remove the hook on the tooth.
Even in this case
there are numerous versions (Fig. 14), the most known and used are two or three
models.
The main
characteristic that they must have is to allow a safe anchorage (grip) of the
hook, allowing to push towards the cervical area of the tooth, without the tips
get stuck in the holes of the hook, and make it possible to easily disengage
the hook placed on the tooth; their handling must also be generally acceptable.
Fig. 14
4.1.
Constituent material
As the punches also
these ones are generally made of stainless steel AISI 420 or 410.
Parts such as
springs, pins etc.. may be made of AISI 301, 303, 304, 316 or 430, depending on
the constructional requirements.
5.
THE HOOK
The hook serves to
hold in place the dam on the tooth, i.e. to ensure that it carries out its
insulating function during the operations to be performed on the tooth.
The hooks have shapes
that promote the attachment on the teeth, there are hooks for the same type of
tooth with larger or smaller size, with indentation in order to increase the
grip on the tooth, with wings or without wings to facilitate the positioning of
the dam.
On the market there
are no less than fifty different shapes of hooks.
5.1
Anatomy of the hook
The hook is an
extremely simple tool, however, is made up of a series of parts, each having a
specific function.
The hooks are
identified (beyond the possible logo of the manufacturer) by a code (Fig. 15)
which indicates the type of tooth it is intended for (E.g. central, premolar
etc..).
Fig. 15
5.2
The parts of the hook
Bow:
its
purpose is to hold together the members of the hook, while maintaining the hook
in tension anchored to the tooth (spring effect);
Holes:
the purpose of the
holes is to allow the insertion of the clamp that must enlarge and then place
the hook on the tooth;
Side
wings:
the purpose of the
side wings is to prevent the dam from sliding back along the hook;
Medial
wings:
the purpose of the
medial wings is that of farther moving the soft tissue; also allowing to
perform the technique providing the positioning of the dam and hook together;
Anchor
blade:
the purpose of the
anchor blade is to hold the hook in position on the tooth;
Indented
anchor blade:
the indentation of
the anchor blade is intended to increase the grip on "slippery"
teeth.
6.
CLASSIFICATION OF HOOKS
The hooks are usually
distinguished into:
- Hooks with wings
- Hooks without
wings.
While the first
facilitate the positioning of the dam, offering a wider visible range to the
operator and contributing in maintaining the dam well tensioned, the second
ones, less bulky, allow an easier use on posterior teeth.
There is also the
variant with smooth or indented blades.
Then we can have the
same type of hook (same shape and same size) but with wings or without wings
and with smooth or indented blade.
This is why the hooks
are identified with a letter, which follows the identification number, which
indicates the absence of the wings and the presence of the indentation; not
always instead the "normal" hooks have the identification letter, in
fact often they only bear the identification number which define hook with
wings and smooth blade, while in some cases they bear the identification letter
"N".
In conclusion the
hooks are identified as follows:
N=
"Normal" hooks, that is with wings and smooth anchor blade
(1-Fig. 16).
W= "Wingless"
hooks, as the word itself says (2-Fig.
16);
T=
"Tiger"
hooks or hooks with side wings and indented anchor blade (3 - Fig 16).
Fig. 16
Examples
of the three types of hook
6.1
Each hook its tooth
The hooks are
manufactured to adapt to multiple teeth, depending on the anatomical shapes and
dimensions of the latter.
There are, for
example hooks for:
- Incisors and
canines;
- Premolar;
- Molar
There are also hooks
for roots.
6.2
What type of hooks to buy to begin using the dam
There are some shape
of hooks (Fig. 17) which can be defined as "essential", that is
sufficient to cover all needs, at least initially, in the use of the dam.
Thus we see these
"basic" shapes:
Fig. 17
1906 S.S. White Dental Mfg. Co. advertisement
for Dr. Delos Palmer's
Set of 32 tooth clamps.
6.3
Hook service life
Although an
instrument extremely simple and free of mechanisms, is also subject to
breakage.
Its weakness is in
the bow that, despite having its original strength and elasticity, loses this
characteristic with repeated use and the many sterilization cycles, which
accelerate the loss of its original elasticity features.
It would be a good
practice, in order to preserve as long as possible the elasticity of the hook
(bow), to avoid holding it tensioned with the clamp for long, before and/or
after its positioning.
6.4
Constituent material
The hooks are mainly
made of stainless steel, however, there are also hooks in plastic material
(Fig. 18) as polymers.
Fig. 18
Example
of a hook in radiopaque polymer
Some types of plastic
hooks are even "adaptable" (Fig. 19).
Fig. 19
Example
of plastic hook adaptable through the bur
The steel used in
principle is an AISI 303, 304, 410, 416A, 420B but also other types of
stainless steel can be used.
For the most part the
surface is "polished" however, there are also satin finished hooks,
to prevent the reflection of light that might disturb the operator during the
course of the operation, however, consider that satin stainless steel is more
prone to corrosion.
On the market all the
pieces seen are available individually packed (with the exception of dams that
are usually in packages containing several pieces) or in kits (Fig. 20); kits,
usually introductory, depending on the manufacturer, can be for example in a
cardboard box containing dam, bow and punch; in plastic even with more than one
set of hooks or still in stainless steel trays, and so on depending on the
manufacturer.
Fig. 20
