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CONTROL OF MOISTURE
Introduction
The production of absorbed dryness by the exclusion of mouth sections
and humidity from the operative field is essential to the correct performances of
most operative procedures.
The term oral environment refers to the following items which require
proper control to prevent them. From interfering with the execution of any
restorative procedures
1. Saliva
2. Moving organs, ie tongue
3. Lips & Check
4. The periodontium
5. The contacting teeth and restoration
6. The sulci, floor of the mouth and palate
7. Respiratory moisture
With six major salivary glands producing saliva there must be a way to
evacuate it either mechanically by the patient own swallowing mechanism or
by chemically reducing its secretion.
All these procedures are important because saliva may obstruct proper
vision and access interfere with and detrimentally affect the setting and
adaptability of restorative materials, modify or regale the effect of medicaments
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and may be sprayed with rotary instruments to propagate infection in the office
atmosphere.
1. Moisture Control
Moisture control refers to excluding sulcular fluid, saliva and gingival
bleeding from the operative field.
It also refers to preventing the handpiece spray and restorative debris
from being swallowed or aspirated.
The advantages of isolation are
1. Dry clean operating field
2. Access and visibility
3. Improved properties of dental materials
4. Protection of patient and operator
5. Operating efficiency
Isolation of the operative fields involves several conceptual elements
1. Moisture control
2. Retraction
3. Harm prevention
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2. Retraction and Access
The details of the restorative procedures cannot be managed without
proper retraction and access. Thus provides maximal exposure of the operative
site. It involves maintaining mouth opening and depressing or retracting the
gingival tissue tongue lips and check.
The rubber dam, mouth props, high volume evacuators, absorbants and
retraction cord are used.
Harm prevention
An axiom taught to every member of the health profession is do not
harm. 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 or debris can be
swallowed. As with moisture control and retraction. The dam, section devices
and absorbants play a role in harm prevention. Harm prevention is provided as
such by the nannee in which these devices are used as by the devices
themselves.
Absorbants and Throat shield
Absorbants such as cotton rolls and cellulose wafer are useful for short
periods of isolation example for examination, polishing etc. and also for topical
fluoride application. Absorbants are isolation alternative in cases where rubber
dam application may not be possible.
Especially along with profound anesthesia absorbants provide
acceptable dryness for procedure such as impression taking and cementation.
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The dental assistant mostly has the job of keeping dry cotton rolls in the mouth.
They should be changed when saturated.
Several commercial devices for holding cotton rolls in position are
available. It is generally necessary to remove the holding appliance from the
mouth to change the cotton rolls. This may be inconvenient and time
consuming.
An advantage of cotton roll holders is that the cheeks and tongues are
slightly retracted from the teeth which enhances access and visibility,
For maxillary teeth
A medium sized cotton roll is placed in the adjacent vestibule.
For the mandibular teeth
One medium sized roll in the vestibule and a larger one
between the teeth and tongue.
The teeth are then dried by short blasts from the air syringe.
Cellulose wafers may be used to retract the check and provide
absorbancy.
While removing these absorbants it may be necessary to moisten them
using the all water syringe to prevent removal of the epithelium from the
cheeks, floor of mouth and lips.
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Throat Shields
These are indicated when small instruments are being used or indirect
restoration placed. This is to prevent aspiration or swallowing of restoration.
High volume evacuators and saliva ejectors
When a high speed hand piece is used air water spray is supplied
through the head of the hand piece to wash the operating site and to act as a
coolant for the bur and the tooth. High volume evacuators are perferred for
suctioning water and debris from the mouth because saliva ejectors remove
water slowly and have little capacity for picking up solids.
McWhecter in 1957 showed that evacuators generally would remove 5L
of water in 2 seconds had 75% to 95% pickup of air and water and would
remove 100% of solids during cavity cutting procedures.
A practical test for the efficacy of the evacuator would be to keep it in
150ml of water it should suck it in 1 seconds.
The tips for these may be
1. Plastic Disposable
2. Metallic auto cleavable
The combined use of water spray and high volume evacuator has the
following advantages.
1. Restorative and tooth debris are removed from the operating site.
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2. Access and visibility are improved.
3. No dehydration of oral tissues.
4. Time is saved as the pauses required for patient to spit and wash are
eliminated.
5. Precious metals are readily salvaged.
6. Quadrant dentistry is facilitated.
Precautions
1. The tip should be as near as possible to the tooth to be operated upon
just distal to it.
2. It should not obstruct the operators view.
3. It should not be so close as to direct the water spray away from the
rotary instrument.
Saliva ejectors
Most patient do not require saliva ejectors as salivary flow is greatly
reduced when the operating site is profoundly anesthetized.
The saliva ejector removes saliva that collects on the floor of the mouth.
It is used in conjunctions with sponges cotton rolls and the rubber dam. It
should be placed in an area least likely to interfere with the operators
movements.
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The tip of the ejector must be smooth and made from a non-irritating
material. Disposable inexpensive plastic ejectors that may be shaped by
bending with the fingers are available. The ejector should be placed to prevent
occluding its tip with tissue from the floor of mouth.
Advantages can be summarized as the
A – adequate access and visibility
B – better patient protection and management
C – control of moisture in operating field
D – decreased operating time of rubber dam i.e.
Rubber Dam
There are many ways to isolate an area of the mouth or a tooth so that
restorative services can be performed without interference from soft tissues,
tongue, saliva or other fluids. Various tongue and cheek retruding devices and
suction methods are used. By far the most complete method of obtaining field
isolation is rubber dam.
History:
It is not realized that the rubber dam was first described over 120 years
ago when in March 1864 Dr. Sanford Barnum first explained its use at meeting
of Connecticut Valley Dental Society in New York. He described his delight in
finding such a simple means of saliva control at a time when saliva control was
sedimentary.
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By the following year, the use of rubber dam was warmly recommended
to profession as an indispensable aid to dental practice and 5 years later in 1870
Dr. J.F.P. Hodson described in detail the methods then in current use. Several
aspects of the technique have not changed greatly from that time. The main
difference from current practice being that rubber dam clamps were not
developed and retention of rubber dam was exclusively by means of wedges
and floss silk ligatures. Rubber dam frames were not used and the edges of
rubber were retracted by neck harness and weights suspended from floss silk
ligatures looped around the tooth. Hodson’s article in 1870 details the
construction of seven types of clamps which were designed solely to achieve
improved gingival retraction and were placed without the aid of clamp forceps.
In 1879 the Ainsworth Rubber dam punch was patented the design of
which has changed little in more than a century.
Dr. W. ST Geo Elliotts in 1878 described clamp forceps gripped the
jaws of he clamp rather than the bow. This arrangement allowed the hole in the
rubber dam to be retained on the forcep tips, thus earliest forerunners of idea of
carrying the rubber dam and clamp to mouth simultaneously.
About the same time (1880) the Hickmann “Lipped” clamp was in use
in which the rubber dam sheet was retained on the clamp between two lips on
each jaw. These were earliest forerunner of present day winged design.
Most of the other design of early clamps and forceps were designed to
tension the clamp by engaging the clamp bow. By 1890 some clamps were
being made with holes in jaws to allow the use of forceps similar to stokes
pattern of today.
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A few of early designs have remained popular to the present day e.g.
“Tees Festooned Clamp” designed in 1870. The only feature lacking when
compared to modern version being holes in each jaw. This design was only one
of the first feature jaw which were directed gingivally or “festooned” a
forerunner of the retentive jaw design today.
Colyer gave a detailed account of techniques in use by 1890 and his
description would be quite familiar to today’s practitioner.
Rubber dam frames were described in early 20th century as Metal
Fernauld’s design. More recent designs have taken advantages of developments
in plastics to produce frames which are radiolucent.
By the time G.V. Black produced his seminal text “Operative Dentistry”
in 1908, the use of rubber dam was firmly established. He strongly advocated
its use stating “the rubber dam should be in place for all amalgam fillings, the
same as for gold…. It is as impossible to make a good amalgam filling as it is a
gold (foil) filling with any moisture present”.
The American Dental Association Council on Dental Materials and
Equipments has acknowledged the use of rubber dam stating in 1986 that “The
use of rubber dam to maintain dry field is essential”.
Advantages of Rubber Dam:
The advantages of rubber dam isolation are:-
1) Dry clean operating field:- The operator can best perform procedures such as
caries removal, cavity preparation, restorative procedure in dry field. Teeth
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prepared and restored using rubber dam isolation are less prone to post-
operative problems related to contamination from oral fluid.
2) Access and visibility:- Rubber dam provides maximal access and visibility. It
act as physical barrier to moisture and retracts the soft tissues. Rubber dam
retracts the gingival tissue, lips, tongue and cheek. Rubber dam provides a
dark, non-reflective background in contrast to operating site thus enhances the
visibility.
3) Improved properties of dental materials by preventing the moisture
contamination of restorative materials during insertion and promotes improved
properties of dental materials.
4) Protection of patient and operator:- The rubber dam protects both patient and
operator. It protects the patient from aspirating or swallowing small
instruments and debris associated with operative procedures. It controls the soft
tissues and their protection from injury. The importance of physical barrier
(which rubber dam provides) between patient and operator and patient’s oral
fluids, has recently become more widely recognized due to risk of treating
undiagnosed carriers of HIV and hepatitis B virus. Thus it provides a pleasant
controlled operating environment. (Operative Dentistry 1986; 11:159)
5) Operating Efficiency:- Use of rubber dam enhances operating efficiency and
increased productivity. Patient management is simplified by avoiding need to
rinse the mouth of debris, improving access to operating area, gingival
retraction and control of gingival haemorrhage and surgically clean field.
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Disadvantages:
1) Time consumption and patient objection are most frequently quoted
disadvantages of rubber dam.
2) Minor damages can occur to marginal gingival and cervical cemetnum.
3) Damage to the restorations such as metal crown margins show microscopic
defects following clamp removal and ceramic crown may fracture at margins
if clamps are allowed to grip the porcelain.
4) Accidental aspiration of the clamps
5) Certain conditions which preclude the use of rubber dam
a. Malpositioned teeth
b. Teeth that have not erupted fully to support retain
c. Third molars
d. Excessive coronal tissue loss
6) Patient suffering from respiratory diseases such as asthma may not tolerate
rubber dam if the breathing through nose is difficult.
7) Contact allergy to latex rubber dam sheet. Two cases of contact allergy to
rubber dam have been reported during last 20 years. One manifesting as
angioneurotic oedema with systemic symptoms and other as contact
dermatitis.
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Materials and Instruments:
1. Rubber Dam:
Rubber dam material is made from natural latex rubber. They are
manufactured as,
a) Continuous rolls available in two widths (125 mm or 150 mm)
b) Pre-cut form available in 5 x 5 inch (12.5 x 12.5 mm) or 6 x 6 (15
x 15 mm) square sheets.
Rubber dam material available in assay of colours. Traditionally black rubber
dam was available but now four alternative colour such as green, blue, grey and
natural (translucent) are there.
Thickness: Rubber dam is manufactured in range of five thicknesses.
Grade Thickness
Mm Inch
Thin 0.15 0.006
Medium 0.20 0.008
Heavy 0.25 0.010
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Extra
heavy
0.30 0.012
Special
heavy
0.35 0.014
Shelf life:- Rubber dam material has shelf life of about 9 months at room
temperature. Shelf life will be reduced in warm storage conditions and so a
refrigerator or freezer is best used if prolonged storage is anticipated.
2. Rubber Dam Punch:
Precision instrument with rotating metal table. These instrument are
used to produce the clean cut holes in the rubber sheet through which the teeth
can be isolated.
Two types of holes are made:-
1) Single hole
2) Multihole
1) Single hole:- Available in two sizes. Single hole punches are used mainly for
endodontic isolation and have the advantage of accurate and consistent punch
point to avail alignment. E.g. Dentsply single hold punch.
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2) Multihole:- More versatile and preferred by authors. They allow holes to be
punched in a range of sizes from 0.5 to 2.5mm in diameter by rotation of axil.
E.g. Ivory pattern (Heraeus Kulzer) punch. E.g. Ash or Ainsworth pattern
punch.
Rubber dam punches should be regularly checked for wear and tear. Three
main problems can arise:-
1) Blunting of the sharp cutting edge to the anvil holes, usually due to prolong
use.
2) Damage to the punch point and anvil, as a result of incorrect alignment.
Punching of holes:- The size of hole punched for each tooth depends on several
factors.
a) Whether the tooth is to be clamped or not
b) Cervical diameter of the tooth
c) The elasticity of rubber dam being used
3. Rubber Dam Forceps:
Rubber dam forceps are needed to stretch the jaws of clamp open in a
controlled manner during placement and removal. Several designs of forceps
are available. Three widely used designs are:-
a) ash or stokes pattern
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b) Ivory pattern
c) University of Washington pattern
All three have a sliding ring between the hinge and forceps handles which can
hold the forcep open and so hold the clamp under tension. These three forcep
differ in their tip design.
University of Washington pattern design provide a definite stop which
positively prevent jamming of instrument tip in the hole in clamp jaw.
It also resists tilting of clamp while held in the forceps.
Stokes and ivory pattern have both notched and pointed tips which engages the
holes in clamp jaws.
Ivory pattern forceps (Heraeus Kulzer) have stabilizers that prevent the
clamp from rotating on the beaks.
Stokes type which have notches near the tips of their beaks in which to locate
the holes of rubber dam clamp allow a range of rotation for the clamp so that it
may be positioned on teeth that are mesially or distally angled.
4. Rubber Dam Frame:
Rubber dam frames support the edges of rubber dam and so retract the
soft tissue and improve access to isolated teeth. It can be metal or plastic.
Fernauld’s frame made of metal was first widely used rubber dam frame.
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The metal frames available now are versions of Young’s design. It is ‘U’
shaped open at the top and this allows the upper edge of rubber to fall slightly
forward away from tip of nose.
Young’s frame design also available in plastic preferred particularly for
endodontic radiographs since radiolucent. The rubber dam is retained by series
of pegs around the edges over which the rubber sheet is stretched. Shape of
pegs can be fine spike with relatively sharp points (young’s) or broad pegs with
blunt type (Hygienic or Fernauld’s).
One type of plastic frame (Nygaard Ostby) is a complete circle
supporting the upper edge of rubber.
Rubber dam harnesses retract only the sides of rubber dam. The harness
is attached to vertical edges of rubber sheet by metal clips from which elastic
pass around the back of the head and apply traction to edges of rubber sheet.
E.g. Woodbury retractor.
Dry dam an alternative to frame and harness which consists of small
sheet of rubber set into the centre of an absorbent paper sheet with light elastic
on either side to pass over the ears. This is useful for quickly isolating anterior
teeth but not suitable for molars bleaching due to absorbent nature of paper
surround.
5. Rubber Dam Clamp:
Rubber dam clamp (retainer) is used to anchor the dam to the tooth to be
isolated. The clamp consists of four prongs and two jaws connected by a bow.
Clamps can be divided into two main groups according to jaw design:-
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Bland
o Winged
o Wingless
Retentive
o Winged
o Wingless
Bland: Bland clamps are recognized by the jaws which are flat and points
directly towards each other and are designed to grasp the tooth at or above the
gingival margin and thus causing minimum gingival damage.
Retentive: Retentive clamps have jaws which are directed more gingivally so
that they can grasp the tooth well below the gingival margin.
Winged: The wings are the small flanges on the outer edges of clamp jaws
which are provided to allow the clamp to be retained in dam during placement.
Clamps are made from metal and non-metal
Metal clamps have traditionally been made from tempered carbon steel plated
to resist corrosion and more recently from stainless steel. Dentsply is producing
gold coloured clamp with diamond grit on jaws. Diamond coating is said to
improve retention on the tooth.
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Non-metal clamps made from polycarbonate plastic (Endo Technic).
Advantage of these clamps is that they are radiolucent. Disadvantage – do not
fit the tooth well and are bulky.
To be secure a clamp must fit around the tooth below the level of
maximum crown width (maximum coronal diameter). The points of the jaws of
the clamps must all contact the crown below this level in four areas. Two on
facial surface and two on lingual surface. This is called ‘Four Point Contact’.
The four point contact prevents rocking and tilting of retainer. This is most
easily achieved by selecting those clamps in which the length of clamp jaws
relate to the mesodistal width of the root.
The jaws should not extend the mesial and distal line angles of tooth because,
1) They may interfere with the placement of matrix and wedge
2) Gingival trauma is more likely to occur
3) Complete seal around the anchor tooth is more difficult to achieve
Correct placement of clamp on an anchor tooth is achieved when:-
1) When the bow is to the distal
2) All four points of jaws are in contact with the anchor tooth.
3) The clamp is gripping the crown of the tooth below its maximum coronal
diameter.
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Clamp placement:
Before a clamp is placed on any tooth, the dental floss should be tied. The
dental floss should be 12 inches (30.5 cm) in length. The floss allows retrival of
retainer or its broken parts if they are accidentally swallowed or aspirated.
The clamp is carried to the tooth using clamp forceps.
The clamp engaged in the beaks of forcep by means of holes in the jaws.
The clamp is oriented in the forcep, so that bow will lie to the distal on the
tooth.
Sufficient pressure is used to tension the clamp and retain it on the forcep. The
handle lock maintains the tension in the clamp.
The clamp is placed on the tooth by opening it sufficiently to pass over the
maximum coronal diameter.
The lingual (or palatal) jaw is placed first in contact with lingual surface of the
anchor tooth. Then the clamp tilted bucally until buccal jaw below maxillary
coronal diameter.
The tension of clamp is released slowly as the buccal jaw is placed.
6. Rubber Dam Napkin:
Rubber dam napkin placed between the rubber dam and patient’s skin
and has following advantages:-
a) It prevents skin contact with rubber to reduce the possibility of allergies
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b) Absorbs saliva seeping at the corners of mouth
c) Act as cushion
d) Provides a convenient method of wiping the patient’s lips on removal of dam
7. Lubricant:
A water soluble lubricant applied in the area of punched holes facilitates
the passing of dam septae through the proximal contacts. Rubber dam lubricant
is commercially available but other lubricant such as shaving cream or soap
slurry are satisfactory cocoa butter or petroleum jelly may be applied at the
coroners of patient’s mouth to prevent irritation. These 2 materials are not
satisfactory rubber dam lubricant because both are oil based and cannot be
easily rinsed from dam once the dam is placed.
8. Hole-Positioning Guides:
a) Teeth as a guide:- The teeth themselves or stone cast of teeth can be
used in marking the dam. The cusp tips of posterior teeth and incisal
edges of anterior teeth can be visualized through the dam, and centers of
teeth are marked on the dam with pen.
b) Template:- Templates are available to guide the marking of dam. These
template are approximately the same size and shape as the unstretched
dam itself.
c) Rubber dam stamp:- Provides a convenient and efficient way of marking
the dam for punching.
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9. Anchors (other than clamps):
Alternatives to clamps are of two types –
a) Employs the area beneath the interdental contacts for retention. These
include interdental wedges or wood sticks inserted below the contact
point or rubber strip passed under tension through contact point and
released to lie beneath the contact area.
b) When the tapering crown/ root surface beneath the maxillary crown
diameter, the rubber dam in this case is retained by ligatures of dental
floss tied around the neck of the tooth or elastic rings which are
stretched through the contact points and released to grip the neck of the
tooth.
guidelines for positioning the holes:
1) Punch an identification hole in upper left (patient’s left) corner of the rubber
dam for ease of location when applying the rubber dam holder.
2) When operating on incisors or mesial of canine isolate from first premolar to 1st
premolar. Metal retainer are not required for this isolation.
3) When operating on canine, it is preferable to isolate from 1st molar to opposite
lateral incisor.
4) To treat a class V lesion on canine, isolate posteriorly to include first molar to
provide access for cervical retainer placement on canine.
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5) When operating posterior teeth, isolate anteriorly to lateral incisor of opposite
side. Anterior teeth included in isolation provide better access and visibility to
operator and finger rest.
6) When operating premolar punch holes to include two teeth distally and extend
anterior up to opposite lateral incisor.
7) When operating molars, punch holes as far distally as possible and extend
anteriorly to include opposite lateral incisors.
8) Isolation of minimum of three teeth recommended except in endodotnic
therapy in which the tooth to be treated is isolated.
9) The distance between holes is equal to the distance from the center of one tooth
to the center of adjacent tooth measured at the level of gingival tissue. It is
generally ¼ inch (6.3 mm).
10)When the rubber dam is applied to the maxillary teeth the first holes are
punched of central incisors which are placed approximately 1 inch (25 mm)
from the upper border so that sufficient material to cover upper lip.
11)When the rubber dam is applied to mandibular tooth, the first hole punched is
for the post anchor tooth that receives the retainer. To determine the proper
location mentally divide the rubber dam into three vertical sections : left,
middle and right.
12)When a cervical retainer is applied to isolate a class V lesion, a heavier rubber
dam is usually recommended for better tissue retraction and the hole should be
punched slightly facially to the arch form to compensate for the extension of
the dam to the cervical area. The farther gignivally the lesion extends, the
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further the hole must be positioned from the arch form. In addition the holes
should be larger and distance between it and holes for adjacent teeth should be
slightly increased.
13)When a thinner dam is used, smaller holes must be punched to achieve an
adequate seal around the teeth because the thin dam greatly elastic.
Application Techniques:
Preoperative Procedures:
Patient’s mouth is examined carefully for calculus deposits, and sharp edges on
restoration.
All contact points in operating field are checked with dental floss.
All roughness and deposits present interdentally must be removed to allow free
passage of rubber dam and prevent tearing.
Anaesthetize the gingiva when indicated
Rinse an dry the operating field.
Before rubber dam is applied to a patient a clear decision has to be made about
teeth should be isolated. Whether a single tooth or a group of teeth is to be
brought through the rubber dam will depend on the procedure to be undertaken.
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When a clamp is to be placed, three techniques of rubber dam application are
commonly used. The clamp can be applied before, after or along with the
rubber dam sheet.
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Technique 1: Clamp placement prior to rubber dam
Step 1:- Testing and lubricating the proximal contacts:- Passing the floss
through the contacts identifies any sharp edges of restorations or enamel that
must be smooth or removed from the teeth to be isolated. Waxed dental tape
may lubricate tight contacts to facilitate dam placement.
Step 2:- Punching the holes:- It is recommended that assistant punch the holes
after assessing the arch form and tooth alignment. Holes can be marked by
using template or rubber dam stamp.
Step 3:- Lubricating the dam:- Lubrication of both the sides of rubber dam in
the area of punched holes using cotton roll or gloved fingertips. The lips and
corners are lubricated with petroleum jelly or cocoa butter.
Step 4:- Selecting the retainer:- Try the retainer on tooth to verify retainers
stability and tie the floss.
Step 5:- Testing retainer stability and retention:- If during trial placement the
retainer seem to be acceptable, remove the forcep and check for stability and
retention.
Step 6:- Positioning the dam over the retainer:- With the forefinger stretch the
anchor hole of dam over the retainer bow first and then under jaw. The
forefingers may thin out to single thickness, the septal dam for the mesial
contact of retainer tooth and attempts to it through the contact lip of the hole
first.
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Step 7: Applying the Napkin:- The operator now gather the rubber dam in left
hand and inserts the right hand through the napkin opening and grasps the
bunched dam held by operator.
Step 8:- Positioning of Napkin
Step 9:- Attaching the frame: The operator unfolds the dam and stretches over
the rubber dam frame.
Step 10:- Attaching the neck strap: (optional) Neck straps attached to the frame
and its tension is adjusted to stabilize the frame and hold the frame.
Step 11:- Passing the tooth to distal contact: If there is tooth distal to the
retainer the distal edge of post anchor hole should be passed through the
contact.
Step 12:- Applying compound (optional): If stability of retainer is questionable,
low fusing modeling compound may be applied.
Step 13:- Applying the anterior anchor (if needed): The operator passes the
dam over the anterior anchor tooth anchoring anterior portion of rubber dam.
Step 14:- Passing the septa through contacts without taper. The operator passes
the septa through as many contacts as possible without the use of dental tape by
stretching the septal dam faciogingivally and linguogingivally with the
forefingers. Pressure from a blunt hand instrument (e.g. beaver-tail burnisher)
applied in the facial embrasure gingival to the contact usually is sufficient to
obtain enough separation to permit the septum to pass through contact.
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Step 15:- Passing the septa through the contacts with tape. Use waxed dental
tape to pass the dam through the remaining contacts. Tape is preferred over
floss because its wider dimension more effectively carries the rubber septae
through the contact. The waxed variety makes passage easier and decreases the
chances for cutting holes in the septa or tearing the edges of holes.
Step 16:- Technique for using tape (optional):- Often several passes with dental
tape are required to carry a reluctant septum through a tight contact, when this
happen previously passed tape should be left in the gingival embrasure until the
entire septum has been placed successfully with passage of time.
Step 17:- Inverting the dam interproximally: Invert the dam into the gingival
sulcus to complete the seal around the tooth and prevent leakage.
Step 18:- Inverting the dam faciolingually: Complete the inversion facially and
lingually using an explorer or beaver-tail burnisher while the assistant directs a
stream of air onto the tooth. This is done by moving the explore around the
neck of the tooth facially and lingually with tip. The tooth surface or directed
slightly gingivally.
Step 19:- Using a saliva ejector
Step 20:- Confirming a properly applied rubber dam
Step 21:- Checking for access and visibility
Step 22:- Inserting the wedges
Technique 2: Applying dam and retainer simultaneously
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Winged/ clamps are used in this technique. The retainer and dam may be
placed simultaneously to reduce the risk of retainer being swallowed or
aspirated before the dam is placed.
In this method first apply the posterior retainer to verify the stable fit.
Remove the retainer and with the forceps still holding the clamps, pass the bow
through the proper hole from the underside of dam.
When using retainer with lateral wings, place the retainer in hole
punched for the anchor tooth by stretching the dam to engage these wings. The
operator conveys the retainer (with dam) into the mouth and positions it on
anchor tooth.
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Technique 3: Applying dam before the retainer
The dam may be stretched over the anchor tooth before the retainer is
placed. It is recommended for anterior teeth perhaps including first premolar.
Preferred technique when double bow or butterfly clamps are selected.
Multiple tooth isolation:
Multiple restorations and quadrant dentistry may require much larger
number of teeth to be isolated.
- Whenever possible clamps should not be placed on the tooth
which requires restoration of proximal surfaces. The clamp is
placed on the next tooth distal to it. If tooth is narrow
mesiodistally the second tooth to the distal is preferable to
provide optimum access.
- When several teeth require treatment the operating field is
extended mesially or across the arch to provide clear access to
all the teeth and maximize retention.
- The more teeth included the better the retraction of lips, cheek
and tongue and better the access.
- The minimum operating field for one tooth to be restored
proximally will therefore include teeth, one distal which will
usually be clamped, and one mesial which is often not clamped.
- As the rubber is passed through each of remaining contacts in
operating field, care must be taken to allow only one edge of
29
the interdental web of rubber dam i.e. leading edge to be carried
initially into each contact area. This process is referred to as
“Knifing the rubber dam through the contacts”, accomplished
by stretching the rubber dam between the fingers to form a thin
“knife edge” aimed at contact point. Knife edge of the rubber
dam can be often “sawn” past the contact pulling it gingivally.
- The edge of rubber dam is inverted proximally first and then
faciolingually. A ligature of dental floss can be placed around
the neck of tooth to hold the rubber dam inverted.
Removal of Rubber Dam:
Before removal of rubber dam, rinse and suction away any debris
that may have collected to prevent its falling into the floor of mouth
during the removal procedures.
Step 1: Cutting the septa: Stretch the dam facially pulling the septal
rubber away from gingival tissues and tooth. Clip each septum with
blunted tip scissors, freeing the dam from the inter proximal space, but
the dam is left over the anterior and posterior anchor teeth.
Step 2:- Removing the retainer: Remove the retainer by engaging it to
the forceps.
Step 3: Removing the dam: Once the retainer is removed, release the
dam from anterior anchor tooth and remove the dam and frame
simultaneously.
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Step 4:- Wiping the lips: Wipe the lips with napkin immediately after
the removal of dam and frame.
Step 5:- Rinsing the mouth and managing the tissue
Step 6:- Extracting the dam
Rubber dam in clinical restorative procedures:
1) Endodontics: Rubber dam application in endodontics is essential to
ensure the patient’s safety during treatment. Aspiration or swallowing of
root canal instruments makes its use an integral part of endodontic
practice.
2) Soft tissue control:- Control of lips, cheek and tongue can prove difficult
with some patient generally the young patient or patients who find hard
to cooperate during restorative procedure. The use of rubber dam
enables fast and efficient treatment in such cases.
3) Cavity preparation:- Rubber dam provides a controlled pleasant
operating environment. The enhanced contrast of cavity margins with
rubber sheet, improved access and safety, moisture control recompense
for extra effort.
4) Specialized clamps / retainer:-
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a. Clamps with the extended bows i.e. the bows lies more distally
than the standard clamp. E.g. Dentsply HW pattern and Ash AD
pattern. They can be used if the preparation distal surface of
clamped tooth is necessary.
b. Modified bow clamps designed to deal with problems
encountered when clamp has to be placed on the third molar.
Standard clamp bow interfere with the ramus of mandible.
Modified bow clamps are so designed that bow lies offset to one
side i.e. palatal side and thus not interfere with ramus.
The standard clamps can be modified by heat treatment and bending the
bow distally.
Modification of rubber dam clamp increases access to distal surface of
anchor teeth.
c. Cervical retainer:- The use of cervical retainer for restoration of
class V cavity was recommended by Markley. E.g. of cervical
retainer Ferrier 212 or Dentsply C. Teeth with cervical cavities
which extend subgingivally usually requires soft tissue at the
gingival margin to be retracted. The retraction force and retention
of these clamps on the tooth is provided mainly by impression
compound which is softened and moulded around the clamp
bows and onto adjacent teeth. While the impression compound is
hardening, pressure is applied to the clamp to press it gingivally
and so reflect the soft tissue margins. As a rule the facial jaw of
the clamp should be 0.5 to 1 mm gingival to anticipated location
of gingival margin of completed tooth preparation.
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5) Fixed bridge isolation:- It is sometimes necessary to isolate one or more
abutment teeth of a fixed bridge. Indications for fixed bridge isolation
include restoration of an adjacent proximal surface and cervical
restoration of an abutment teeth.
The rubber dam is punched as usual except for providing one large hole
for each unit in the bridge. Fixed bridge isolation is accomplished after
the remaining dam is applied.
A blunted curved suture needle with dental floss attached is threaded
from the facial aspect through the hole from the anterior abutment and
bask through the same hole on lingual side. The needle direction is then
reviewed as it is passed from the lingual side through the hole for the
second bridge unit, then under the same anterior connector and through
the hole of second bridge unit on facial side. A square knot is then tied
with the two ends of floss thereby pulling the dam material smugly
around the connector and into gingival embrasure.
6) Rubber dam in Pedodontics:- The age of the patient often dictates
changes in the procedures of rubber dam application. Because young
patient have small dental arches than adult patient holes should be
punched accordingly. For primary teeth isolation is usually from most
post tooth to canine as the same side. Rubber dam sheet is smaller 5 x 5
inch (12.5 x 12.5 cm).
The unpunched rubber dam is attached to the frame, the holes are
punched, the dam with frame is applied over the anchor tooth, and
retainer is applied. The jaws of the retainers should be directed more
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gingivally because of short clinical crowns or because the anchor tooth’s
height of contour is below the crest of gingival tissue.
SS White No.27 recommended for primary and Ivory No.214
retainer for young permanent teeth.
Isolated teeth with short clinical crowns (other than anchor tooth)
may require ligation to hold the dam position. Rubber dam described as
“Rubber Rain Coat” for young children.
Errors in Application and Removal:
Certain errors in application and removal can prevent adequate
moisture control, reduce access and visibility or cause injury to the
patient.
1) Off center arch form:- A rubber dam punched off center may not
adequately shield the patient’s oral cavity, allowing the foreign matter to
escape down the patient’s throat. It can result in excess of material
superiorly that may occlude the patient’s nasal airway.
2) Inappropriate distance between the holes:- Too little distance precludes
adequate isolation because holes of rubber dam are stretched and will
not fit smugly around the necks of the teeth. Conversely too much
distance causes wrinkles between the teeth.
3) Incorrect arch form of holes:- If the punched arch form is tooth small,
the holes will be stretched open around the teeth, permitting leakage.
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4) Inappropriate retainers:-
a. If too small, resulting in occasional breakage when jaws are
overspread.
b. Unstable on anchor tooth
c. Impinge on soft tissue
d. Impede wedge placement.
5) Retainer pinched tissue: Jaws and prongs of rubber dam retainer usually
depress the tissue but should not impinge on it.
6) Incorrect location of hole for class V lesion:- If there is an incorrect
location of hole for class V lesion and hole is not punched facial to arch
form, circulation of interproximal tissue will be diminished.
7) Sharp tips on No.212 retainer:- Sharp tips on retainer No.212 is dulled to
prevent damaging the cementum.
8) Incorrect technique for cutting septa:- During removal of rubber dam an
incorrect technique for cutting the septa may result in cut tissue or a torn
septa.
Washed Field Apparatus:
This method employs inexpensive plastic tubing that is attached
to saliva ejector hose at one end and to the clamp or rubber dam itself at
the other. Childers and Marshall’s have recommended the use of clear
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vinyl tubing with inside diameter of 0.0625 inch and an outside diameter
of 0.125 inch. As connector for saliva ejector hose recommended clear
vinyl tubing with an inside diameter of 0.125 inch and outside diameter
of 0.025 inch. The end of smaller diameter tube is carried under the
rubber dam frame and tucked under the bow o a wing of rubber dam
clamp in back of dam tubing may be attached to rubber dam by
cyanoacrylate adhesive. The washed field apparatus is used for
evacuation of fluids from dam when no assistant is available.
Alternative isolation aids
Retraction cord when properly applied can be used for isolation and
retraction in the direct procedures of treatment of cervical lesions in facial
veneering as well as in indirect veneers.
The gingival retraction when moistened with a non caustic styptic may
be placed in gingival sulcus to control sulailar seepage and or hemorrhage.
Most brands are available with and without the voso constrictor
epinephrine which acts to control sulculae fluids.
A properly applied retraction cord, will improve access and visibility
and help prevent abrasion of gingival tissue during cavity preparation.
Antisalivary drugs
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The use of drugs in restorative dentistry to control salivation is rarely
indicated and generally limited to atropine.
Is with any drug the operator should be familiar with its indications
contra indications and side effects. It is important to remember that atropine is
contra indicated for nursing mothers and for patients with glaucoma.
Some Anti histaminics like Hi receptor antagonists also cause dryness of
mouth due to anti cholinergic action but they inhibit the action of local
anesthesia so are contra indicated.
Although several methods and devices are available to create a dry
working field. The rubber dam is one of the most ideal the working field that is
produced is in principle.
In medicine, surgical procedures are done with controller operating
field’s surrounded by aseptic environment. An attempt should be made in
restorative dentistry to work only on clean teeth and on a patient who is under
control. Control should mean not only the elimination of moisture but the
elimination of humidity as well utilizing all the above mentioned measures.
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Contents
1. Introduction
2. Methods of Isolation
3. Rubber Dam
4. Drugs
5. Conclusion
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