martedì 15 ottobre 2013

8 THE RUBBER DAM TECHNIQUE - TOOLS USED


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



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