Tooth Separation, Wedges and Control of Moisture

Definition

Tooth separation or tooth movement is the act of either separating the

involved teeth from each other, or bringing them closer to each other or

changing their spatial position in one or more dimensions.

This is done in order to facilitate the creation of a physiologically

functional contact, contour and occluding anatomy in the restored tooth.

Indications for tooth movement

1. To bring drifted, tilted or rotated teeth to their original physiologic position

for proper reproduction of proximal surfaces during restoration. This is

done to avoid flat or concave proximal surfaces and contact areas in the

restoration, and to regain the mesio-distal dimension of the dental arch.

2. To close space between teeth when it cannot be closed by the restoration

alone.

3. To move teeth to another location more physiologically acceptable by the

periodontium.

4. To move teeth occlusally (extrusion) or apically (intrusion) in order to make

them restorable.

5. To move teeth from a non-functional or traumatically functional location to

a physiologically functional one.

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6. To move teeth to a more esthetically pleasing position.

7. To move teeth to a position that increases the resistance and retention of a

restoration.

8. To create space sufficient for the thickness of the matrix band

interproximally.

9. To facilitate access to proximal cavity preparation specially class III

preparations.

10. To detect proximal decay.

11. To facilitate polishing of the proximal surface of a restoration.

12. To remove foreign bodies impacted proximally that are not dislodged by

floss or brushes.

History : Rapid separators

The first separator was introduced by Dr. O.A. Jarvis in 1874.

A number of separators have been developed by dentists since the one by

Jarvis. Notable among them are these by Dr. Safford. G. Perry and Dr. W.I.

Ferrier.

Dr. Harry A. True developed the single bow non interfering separator at the

college of Physicians and surgeons of San Francisco, School of Dentistry.

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Principals of tooth movement

i. Rapid or immediate tooth movement.

ii. Delayed or slow tooth movement.

Rapid or immediate tooth movement

This is a mechanical type of separation that creates either proximal

separation at the point of the separators introduction or improved closeness of

the proximal surface opposite the point of the separators introduction.

Prior to separation

Open distal contact caused by mesial drifting of first molar due to mesial

carious lesion.

After separation

Closed distal contact Opened mesial contact to facilitate instrumentation and restoration.

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Indications for rapid tooth movement

Besides the general indications it can be used :

1. Preparatory to slow tooth movement.

2. To maintain a space gained by slow tooth movement.

This type of tooth movement should not exceed the thickness of the

involved tooths periodontal ligament as more separation can tear the ligaments

at one site and crush them at the other i.e. it should not exceed 0.2-0.5mm.

Methods of rapid tooth movement

1. Wedge method examples

a. Elliot separator.

b. Wood or plastic wedges.

2. Traction method

a. True separator.

b. Ferrier double bow separator.

1. Wedge method

Separation is accomplished by the insertion of a pointed wedge shaped

device between the teeth to create separation at that point or closure on the

opposite proximal side of the involved teeth. The more the wedge moves

facially or lingually greater will be the separation.

Examples : Elliot separator

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This is indicated for short duration separation that does not require

stabilization. It is useful in examining proximal surfaces or in final polishing of

restored contacts.

Procedure: Adjust the two opposing wedges of the separator interproximally

so that they are positioned gingival to the contact area not impinging on the

interdental papillae or the interceptal rubber dam. Move the knob clockwise so

that the wedges move towards one another establishing the desired separation.

Wood / Plastic wedges

These are triangular shaped wedges usually made of medicated wood or

synthetic resin. In cross section the base of the triangle will be in contact with

the interdental papillae (gingival to the margin of the proximal cavity).

The two sides of the triangle should coincide with the corresponding

sides of the gingival embrasure i.e. mesial and distal. The apex of the triangle

should coincide with the gingival start of the contact area.

The wedge is used in conjunction with matrices for inserting plastic

restorative matertial.

Wedges perform the following functions

i. They assure close adaptation of the matrix band to the tooth surface.

ii. They occupy the space designated to be the gingival embrasure

preventing the restorative material from impinging on it.

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iii. They define the gingival, facial and lingual extent of the contact area

thus assuring the health of proximal periodontal tissues.

iv. They create some separation to compensate for the thickness of the

matrix band.

v. They established atraumatic retraction of the rubber dam and the gingiva

from the gingival margin of the cavity preparation.

vi. They produce temporary hemostasis and minimizes moisture

contamination in the area of restoration.

vii. They immobilize the matrix band.

viii. They protect the interproximal gingiva from the unexpected trauma.

Although wedges are supplied in different sizes to suit different

locations, they should not be used as supplied. The wedges should be trimmed

to exactly fit each gingival embrasure.

Classification of wedges according to the materials

I. Wooden Eg : Orange wood

Plastic Eg : Synthetic.

II. Preformed

Custom made. According to the situation made by Dr. (Orange wood).

III. Medicated Eg : Hemo wedges.

Non medicated orange wood.

IV. Synthetic : Synthetic resin.

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Natural : Orange wood.

Plastic wedges which permit transmission of light are available for use

with posterior composite restoration

Advantages

1. Of wood wedges are they can be easily cut and trimmed.

- They absorb water intraorally which causes them to swell, improving

their interproximal retention.

2. The main advantages of resin wedges is that they can be plastically molded

and bent to correspond with the configuration of the interdental col.

Wedge placement : Break off approximately 1.2cm of a round tooth pick.

Hold the wedge with a plier. Wet the gingival aspect of the wedge with the

lubricant. Insert the pointed tip from the facial or lingual embrasure whichever

is larger, slightly gingival to the gingival margin, wedging the matrix band

tightly against the tooth and margin.

If the wedge is occlusal to the gingival margin the band will be pressed

into the preparation, creating an abnormal concavity in the proximal surface of

the restoration.

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“Piggy-back” wedging

This technique can be used (1) when proximal box is shallow gingivally

(2) interproximal tissue level has receded.

If the wedge is significantly apical of the gingival margin a second

smaller wedge may be piggy backed on the first wedge to adequately wedge

the matrix against the margin.

Double wedging

It is permitted, if access allows, to secure the matrix when the proximal

box is wide facio-lingually. It refers to inserting two wedges one from the

lingual and a second from the facial embrasure. Two wedges help to ensure that

the gingival corners of a wide proximal box can be properly condensed as well

as to minimize gingival excess.

Wedge – wedging

Occasionally a concavity may be present on the proximal surface

gingivally of the contact and extending as a fluting onto the root eg : the mesial

of the maxillary first premolar. A gingival margin located in this area will be

similarly concave.

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To wedge a matrix band tight against such a margin a second pointed

wedge can be inserted between the first wedge and the band.

Test for tightness of the wedge by pressing the tip of an explorer firmly

at several points along the middle two thirds of the gingival margin to verify

that the matrix cannot be moved away from the gingival margin.

Selection of wedge shape

- Some operators prefer a triangular shaped wedge (anatomic wedge)

because it can be modified by a knife or scalpel blade to conform to

the approximating tooth contours.

- The triangular wedge is recommended for the deep gingival margin.

When the gingival margin is deep the base of the triangular wedge

will more readily engage enough tooth gingival to the margin

without causing excessive soft tissue displacement.

- It is also indicated with Tofflemire mesio-occluso distal band.

- The round tooth pick wedge is preferred with conservative proximal

boxes because its wedging action is more nearer the gingival margin

than with the triangular wedge.

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Traction method

This is always done with mechanical devices which engage the proximal

surfaces of the teeth to be separated by means of holding arms. These are

mechanically moved apart creating separation between the clamped teeth.

Examples : Non-interferring true separator.

Indications

- When continuous stabilized separation is required.

Advantages

- Separation can be increased or decreased after stabilization.

- The device is non interfering.

Procedure

Insure that the jaws of the separator are closed together. Apply the jaws

closest to the bow against the tooth to be operated upon. The jaws further from

the bow will move later in the adjustment. Next the separator is stabilized by

applying a piece of softened compound to the teeth under the separator by

introducing it in their buccal and lingual embrasure. Also cover the incisal or

occlusal surface under the separator and over the separator with impression

compound.

The movable jaws are moved over the approximating tooth exerting the

pressure of separation. The nut on the facial side should be moved first until the

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jaw touches the surface needed then the nut of the lingual side is moved.

Repeat the adjustment until the desired amount of separation is obtained.

Ferrier double bow separator

With this device, the separation is stabilized throughout the operation.

Advantages : The separation is shared by the contacting teeth and not at the

expense of one tooth as with true separator.

Procedure : The ferrier separator is available in six different sizes for various

positions in the mouth.

Each instrument has two pairs of jaws which is placed against the

enamel of the proximating surfaces of the teeth to be separated. The arms

should be gingival to the contact area. The teeth are moved apart by turning

threaded bars on the buccal and lingual sides of the instrument. First one bar

should be given two or three quarter turns and the other the same number. This

is done with a wrench supplied with the instrument.

Compound material is applied gingival and occlusal to the mesial and

distal bows as described for the previous separator thereby stabilizing it by

attaching it to the underlying teeth.

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Slow or delayed tooth movement

Indications

When teeth have drifted or tilted considerably rapid movement of teeth

to the proper position will endanger the periodontal ligaments. Slow tooth

movement over a period of weeks, will allow the proper repositioning of teeth

in a physiologic manner.

Methods

i. Separating wires : Thin pieces of wire are introduced gingival to the

contact then wrapped around the contact area. The two ends are twisted

together to create separation not to exceed 0.5mm. The twisted ends are

then bent into the buccal or lingual embrasure to prevent impingement

of soft tissue. The wires are tightened periodically to increase the

separation. This is a very effective method of slow tooth movement. The

maximum amount of separation will be equivalent to the thickness of

the wire.

ii. Oversized temporaries : Resin temporaries that are oversized mesio-

distally achieve slow separation. Resin is added to the contact areas

periodically to increase the amount of separation which will not exceed

0.5mm per visit.

iii. Orthodontic appliances : for tooth movement of any magnitude fixed

orthodontic appliances are the most effective and predictable method

available.

iv. Gutta percha.

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Control of Moisture

Operative dentistry cannot be executed properly unless the moisture in

the mouth is controlled. Moisture control refers to excluding sulcular fluid,

saliva and gingival bleeding from the operating field. It also refers to

preventing the handpiece spray and restorative debris from being swallowed or

aspirated by the patient.

Several methods and devices are available for creating a dry working

field, but isolation of the teeth with the rubber dam is the most ideal. The

rubber dam technique is fundamental and essential to routine quality patient

care.

The Rubber Dam

In 1864 S.C. Barnum a New York dentist introduced the rubber dam

into dentistry.

Purpose

The rubber dam is used to define the operating field by isolating one or

more teeth from the oral environment. The dam eliminates saliva from the

operating site and retracts the soft tissue.

Advantages

1. Dry, clean operating field : Rubber dam isolation is the preferred method of

obtaining a dry field.

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2. Access and visibility : The rubber dam retracts the lips, cheeks and tongue.

Gingival tissue is also retracted to provide better access and visibility to

gingival aspects of the cavity preparation.

3. Improved properties of dental materials : As the rubber dam prevents

moisture contamination of restorative materials during insertion.

4. Protection of the patient and operator : The rubber dam protects the patient

from aspirating or swallowing small instruments or debris associated with

operative procedures. The operator is protected from infections present in

the patients mouth.

5. Increased operating efficiency.

Disadvantages :

i. Time consuming.

ii. Patient objection.

Conditions that preclude the use of rubber dam

1. Teeth that have not erupted sufficiently to receive a retainer.

2. Some third molars.

3. Extermely malpositioned teeth.

4. Patients suffering from asthma.

5. Psychological reasons for patient not able to tolerate the rubber dam.

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Materials and Instruments

1. Rubber dam material or sheet

The dam material is available in 5 x 5 inch or 6 x 6 inch sheets.

Sheets are available in a variety of thickness ranging from.

Thin 0.15 mm

Medium 0.2 mm

Heavy 0.25 mm

Extra heavy 0.3 mm

Special extra heavy 0.35 mm

The thicker dam is more effective in retracting tissue, more resistant to

tearing and recommended for isolating class V cavities – The thinner material

has the advantage of passing through the contacts easier.

Rubber dam material is available in both light and dark colours. Dark

colour is preferred for contrast.

Rubber dam material has a shiny and a dull side, because the dull side is

less light reflective it is placed facing the occlusal aspect.

2. Rubber dam holder

It positions and holds the borders of the rubber dam. Rubber dam

holders are of various types and designs.

a. Facial frames : b. Cervical traction

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- Facial frames provide circumferential stretching around the mouth

itself eg :

- Young holder which is a U-shaped frame with small projections for

securing the borders of the rubber dam. It is easy to apply and

comfortable for the patient.

- Cervical traction has a strap going around the head or neck. Cervical

traction provides greater access to the operator but is uncomfortable

to the patient.

3. Rubber dam retainer : (Clamp)

The clamp is used to anchor the rubber dam to the most posterior tooth

to be isolated.

The retainer consists of four prongs and two jaws connected by a bow.

Many different sizes and shapes are available with specific retainers

designed for certain teeth (such as anterior, premolar, molars).

When positioned properly on a tooth the retainer would contact the tooth

in four areas, two on the facial surface and two on the lingual surface. This four

point contact prevents rocking or tilting of the retainer.

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Retainers are also available as wingless and winged retainers. The

winged retainer has both anterior and lateral wings. The wings are designed to

provide extra retraction of the rubber dam from the operating field and to allow

attaching the dam to the retainer before anchoring it to the tooth after which the

dam is removed from the lateral wings.

Disadvantage of the winged retainer is that wings interfere with the

placement of matrix bands and wedges

Retainer Numbers

W56 - Most molars

W7 - Mandibular molars

W8 - Maxillary molars

W4 - Premolars

W2 - Smaller premolars

W27 - Terminal mandibular molar teeth requiring preparations involving

distal surface.

Modified No. 212 retainer for treatment of cervical lesions.

The retainer which is applied after the rubber dam is in placed should be

tied with a dental floss for retrieval of the retainer incase it breaks while

placing or is accidentally swallowed.

4. Rubber dam punch

The punch is a precision instrument having a rotating metal table with

six holes of varying sizes and a tapered, sharp pointed plunger. The plunger

should be centred in the cutting hole.

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5. Rubber dam retainer forceps

The forceps is used for the placement and removal of the retainer from

the tooth.

6. Rubber dam napkin

The napkin is placed between the rubber dam and the patients skin. It

has the following advantages.

a. Prevents skin contact with rubber to reduce the possibility of

allergic reactions in sensitive patients.

b. Absorbs saliva at the corners of the mouth.

c. Acts as a cushion.

d. Provides a convenient method of wiping the patients lips on

removal of the dam.

7. Lubricant

A water-soluble lubricant applied in the area of the punched holes

facilitates the passing of the rubber dam through the proximal contacts.

8. Modeling compound

Low fusing modeling compound is sometimes used to secure the

retainer to the tooth to prevent retainer movement during the operative

procedure.

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9. Template

It is used to mark the correct position of the hole before it is punched.

To assure uniformity of rubber borders after applications two landmarks should

be kept in mind. For maxillary applications the incisors should lie one inch

from the upper border, for mandibular applications the most posterior hole is

slightly right or left of the center of the rubber sheet.

High volume evacuators

When a high-speed handpiece is used high volume evacuators are

preferred for suctioning water and debris from the mouth. The high volume

evacuator has a diameter of 10 mm. The tip is usually beveled with the flat

surface facing the area being cut. Usually the assistant hold the tip, and they

should not push the soft tissues or rest on them.

Saliva ejectors :

It removes saliva that collects on the floor of the mouth. The tip has a diameter

of 4 mm and is left in the mouth during the procedure. The tip resting on the

floor of the mouth, under constant negative pressure can draw delicate soft

tissue into its orifice resulting in irritation of the mucosa. The ejector should be

inspected frequently to insure against occlusion of the tip.

Cotton rolls and cellulose wafers

Absorbents such as cotton rolls and cellulose wafers are helpful for short

periods of isolation (eg : examination, polishing). Using a saliva ejector in

conjunction with absorbents will further control salivary flow. Cotton rolls

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come in a variety of lengths and sizes. The maxillary teeth are isolated by

placing a cotton role in the vestibule.

The mandibular teeth are isolated by placing one cotton roll in the

vestibule and one between the teeth and tongue.

Another popular absorbent medium is the Thita “Dri-Angle”. Inserted in

the right or left vestibule it is effective in absorbing secretions from the parotid

duct.

Drugs

The use of drugs in restorative dentistry to control salivation is rarely

indicated and is generally limited to anti-sialogogues like atropine. This is

given 5 mgm half hour before the appointment. This will decrease salivary

flow but should be avoided in patients with high ocular pressure or with

cardiovascular problems.

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Conclusion

An important consideration of isolating the operating field is preventing

the patient from being harmed during the operation. Excessive saliva and hand

piece spray can alarm the patient. Small instruments and restorative debris can

be aspirated or swallowed. Soft tissues can be damaged accidentally. Rubber

dam, suction devices, absorbents contribute not only to harm prevention but

also to patient comfort and operator efficiency.

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