Field isolation for restorative dentistry The goals of operating field isolation : 1- moisture control

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Cons , lec 13


Dr. Sahar

Field isolation for restorative dentistry

The goals of operating field isolation :-

1- Moisture control

-A clean , dry field is required for operative procedures ( you can't have a good operative procedures with moist "blood , saliva , debri … " ).

-Moisture control refers to :-

1- excluding sulcular fluid, saliva, and gingival bleeding from the operating field.

(these are the possible source of contaminations ).

2- Prevention of handpiece spray and restorative debris from being aspirated or swallowed by the patient. (this point refers more to Harm Prevention " point 3" ).

2- Retraction & access
which involves maintaining an open mouth and depressing or retracting the gingival tissue, tongue, lips, and cheeks away from the operating field ; to protect them , have a proper access for the operating field & provide maximal exposure of the operating site.

3-Harm Prevention

-Prevent the patient from being harmed during the operation by small instruments and restorative debris that can be aspirated or swallowed.

-if they are:- swallowed  ends up in the stomach it's not that problem.

aspirated ends up in the lung here it's a big problem .

-Prevent soft tissue accidental damage.

(both low & high speed burs can cause injury to the soft tissues).

-This will lead to more patient comfort and alleviate the patient’s anxiety toward dental treatment.

-: Advantages of field isolation
1-Dry, Clean Operating Field.

2-Access and Visibility.

3-Improved Properties of Dental Materials.

" improve" here doesn't mean ,got a properties of dental materials more than they originally own , it means "optimize the properties of dental materials" ; e.g. The composite needs a dry field to bond with enamel and dentin so if the tooth substrate is contaminated with saliva, blood, or other oral fluids ,bonding to enamel and dentin is unpredictable , so here The rubber dam prevents moisture contamination of restorative materials during insertion and promotes improved properties of dental materials.

4-Protection of the Patient and Operator.

-RD protects patient against swallowed a small instruments.

-RD protects operator against patient's saliva.

(RD offers an effective infection control barrier for the dental office).

5-Operating Efficiency

-RD isolation improved quality and quantity of restorative treatment delivered; e.g. you can do all the steps of composite (itching, bonding & placing the filing ) continuously without any interruption , without RD the patient may ask you to let him rinse after each step , which means that you have to repeat that step again .

Remember! The composite needs a dry field to bond to the enamel and dentin.

-Excessive patient conversations are discouraged.

-The time saved by operating in a clean field with good visibility may more than compensate for the time spent applying the rubber dam.

Disadvantages of field isolation:-
1- Time consuming

The time required for proper isolation with RD will take about 3-5 min, which is the same time required for the onset of anesthesia.

2-Maybe the patient objectionable

With the simplified technique of placement and removal nowadays, patients are less objectionable to RD. It makes them comfortable and feeling secure after it is placed.

All the previously mentioned advantages and disadvantages are relevant to the dental dam. *

*Put in mind!! Achieving an effective isolation is more important than the specific technique used.

* Remember!! Restorative dentistry = Operative dentistry = Placing filling.

Rubber dam isolation

It is the most successful method of isolating the operating field(it's the standard of care).-

-It is used to define the operating field by isolating one or more teeth from the oral environment(in contrast to endodontic treatment where we isolate only one tooth ). Introduced into dentistry in 1864 ( it's an old method) . -
Materials and instruments:- (plz check the pictures from the doctor's slides)

1- Dam Material (=Rubber sheet )

*sterile or non-sterile

the sterile dam comes individually packed.

non-sterile dams are all packed in the same packet.

* different sizes

(4 X 4)inch , (5 X 5)inch more used in endodontic treatment.

(6 X 6)inch more used in restorative dentistry.

*different thickness (thin, medium, heavy and extra-heavy)

thin  is easier to glide interproximally specially when the contacts are tight more used in endodontic treatment.

thick more effective in tissue retraction and resistant to tearing good to use with class V isolation more used in restorative dentistry.

*different colors (dark or light)

dark  is recommended in restorative dentistry because it is less light reflective  more complement to the color of our teeth which is in (white –yellow) or (yellow –brown) range . So our choose mostly is green or blue dam.

      • *Latex or latex-free.

      • *The RD has a shiny side and a dull (mat) side.The dull side should face the operator

(facing the occlusal side of the isolated teeth) because it's less light reflective.

-Light reflection affects our perception of the color , you need to choose the composite shied which has the closest possible match to the patient existing teeth, the shiny side will reflect the light to your eyes and interfere with your shied selection,so don't use this side.

* Dark, heavy 6X6 RD is usually indicated for restorative dentistry.

2-RD Holder or Frame

To maintain the borders of the rubber dam in position. It could be metal or plastic.

3-Retainer or Clamp

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

-The prongs should contact the tooth securely 2 on the facial and 2 on the lingual. This four-point contact prevent tilting or rocking of the clamp which might injure the gingiva or the tooth. The prongs of some retainers are gingivally directed (inverted) and are helpful when the anchor tooth is only partially erupted .

-The jaws of the retainer should not extend beyond the mesial and distal line angles of the tooth because: (1) they may interfere with matrix and wedge placement.

(2) trauma in interdental papilla & gingiva is more likely to occur.

(3) a complete seal around the anchor tooth is more difficult to achieve.

-the bow must be directed distally & It is applied after the rubber dam is in place.

*The retainer is used to :-

1- anchor the dam to the most posterior tooth to be isolated.

2- retract gingival tissue

* Many different sizes and shapes are available.

- anterior tooth clamp (No.212)has two bows "mesially & distally" , you can use it for anterior teeth & in class V even it at premolars.



*Wingless and winged retainers are available also.

-Winged clamps have anterior and lateral wings. They provide extra retraction of the RD. they also allow the attachment of the dam along with the clamp at the same time. mostly used in endodontic treatment

-The wingless retainer is better for operative procedures since it does not interfere with the wedges & matrix band placement.

* The clamps should be tied with a long dental floss (30 cm) before it is placed in the mouth. It is better to go through both holes in the jaws of the clamp wrapping around the bow, because the bow might break.

The floss allows retrieval of the clamp or its pieces when it is accidentally aspirated or swallowed.

(when the clamp is broken the RD will loss its retention then the patient may swallow it ).

*A clamp is not usually required for isolating anterior teeth except class V.


The rubber dam punch is a precision instrument having (a rotating metal table (disk) with six holes of varying sizes + a tapered, sharp-pointed plunger).

5-The forceps

The forceps used to place and remove the clamp from the tooth.(carrying the clamp to the oral cavity).

6- The napkin
*The napkin ( looklike the RD )is placed between the RD and the patient’s face.

*uses :- 1-It reduces sensitivity to the dam material.

2-absorbs seeping saliva at the corners of the mouth.

7-water-based lubricant

Applying the lubricant to both sides of the dam in the area of the punched holes aids in passing the dam through the contacts.

8- Modeling compound (such as the green stick)

it is used to prevent retainer movement during the operative procedure.

(we use it in the isolation of the anterior teeth ; according to the morphology of the anterior teeth , there is no prominent high of contour as the posterior ones , so the anterior tooth clamp tends to move , to prevent this movement we use this material , just heat it and put it at the two jaws). It’s the same compound material that we used in making first impression at the lab.

9-waxed dental floss

-In multiple isolation (isolating more than one tooth) we use the dental floss to facilitate passing the dam between the contact areas.

-To secure the dam anteriorly or to anchor the dam on any tooth where a retainer is contraindicated. (from the book)

Hole Size

You can make the holes by using punch. Smaller size holes should be used for incisors, canines and premolars. Larger holes should be used for molars.

Hole position ( where to place the holes? ) :-

" Experience eliminates the need for these aids"

1-use the patient's teeth as a guide .

2-using templates or stamps.

-Account for "=make adjustment for" malpositioned , missing teeth ( if there is a tooth missing, skip it "don’t put a hole for it") and partial fixed teeth ( in the case of the bridge "3 teeth liked together "you can't make a hole to each tooth , just make one large hole for all , by another words the bridge needs only on large hole ).

-Punch the hole more facial in the case of class V preparation for the restored tooth the clamp should be in subgingival position , in other cases it will be in free gingival margin.

-The hole for the upper central incisors should be punched around 0.9 inches away from the above edge.
Question:- Where to place your holes, if u want to make isolation from upper right 6 to the upper left 6 ?
Answer:- You have to follow the arch form , usually with experience you can put the holes in the correct position, but novices would rather use “ templates or stamps”.
*This is a rough guideline where you should place your holes.

RD isolation for occlusal restorations in premolar or molar teeth

Question:- You want to make class I preparation for molar assume 6 ,should you isolate the (4 ,5 ,6 ,7 ) ?

Answer:- It’s better to do that , and you can make what’s called limiting isolation or you can make single tooth isolation (isolating the tooth being operated on; in our case here it's the tooth # 6) .

.∙. Only the tooth to be restored can be isolated, although isolating more teeth will ensure better access and visibility.

Rubber dam application for proximal cavities in posterior teeth ( class II & III )
The more teeth that are passed through the rubber, the better will be the access.-

-If a molar, premolar, or distal surface of a canine is to be restored, the major part of that quadrant is usually isolated.

-as a general guideline , if you prepare a tooth in the lower right quadrant , you have to isolate all the lower right quadrant +opposing central incisor. e.g. you have to prepare a class II cavity on the lower right 6 ,so you have to isolate (1-7)from the right quadrant +(1)from the left quadrant , this is ideally. Practically , this is not always happened , if you do multiple restorations then this is the best to do otherwise limiting isolation is fine.(in limiting isolation, one distal tooth and two mesial teeth are isolated in addition to the tooth to be operated on).*

* the doctor said that , in limiting isolation, one distal tooth and one mesial teeth are isolated in addition to the tooth to be operated on , which different from what is mentioned in the slides and the book , I will ensure from this point from the doctor Insha'allah.

-A clamp retains the rubber on the most distal tooth and a contact point holds the rubber anteriorly.

3 2 1
4 5 6

*p1:-Using a winged clamp for the simultaneous application of the clamp and the dam . Then we use the forceps to put the clamp on the tooth (here it’s u6) .

*p2+p3 :-Releasing the wings of the RD with a blunt instrument ( there is RD above the wings of the retainer so you have to put it under the wing in order to have a proper seal , you can use a blunt instrument such as condenser to do this , note that the holes are green in color which is the color of underling RD) .

*P4:-Knifing the RD through the contact areas of the teeth to be isolated(knifing= vertical introduce to the dam between the contact area)èinitial entrance to the RD.

*P5:-Flossing through the contacts. ( to ensure that the RD is below the contact area , if it occlusal to contact area it will be unstable and we won't have a perfect isolation) .

*P6:-Place a wedge to prevent tearing the RD or injuring the gingiva during cavity preparation.

In case the clamp interferes with the matrix band placement, the clamp can be removed from the tooth while holding the dam down then place the matrix band and retainer. The band in this case will be serving as a clamp and hold the dam in position.

Rubber dam application for anterior teeth

-Clamps are used less often in this situation.

-Instead of using clamps, the dam can be stabilized on the most posterior teeth to be Isolated (often the canines or premolar teeth), using an extra piece of rubber dam, a waxed dental floss ligature or relying on the natural teeth contacts to hold the dam in place.

-A sufficient number of teeth should protrude through the rubber for its stability and for good access (Usually from canine to canine ,even you do multiple filings or single one you have to isolate from canine to canine, if canine is involved in restoration then from 1st PM to 1st PM on the contralteral side).

- You can place a clamp over the dam on top of an unisolated tooth to gain more access and retraction. However, care must be taken not to injure the gingiva of that tooth.

RD application for class v

Class v , we use anterior teeth clamp (No.212) , Punch the hole more facial in the case of class V preparation for the restored tooth the clamp should be in subgingival position , in other cases it will be in free gingival margin.

Inverting the RD

-The RD should be inverted at least in the area of the tooth to be restored. Once the RD is placed the rubber dam at the neck of the tooth will act as a valve. When first placed the edge of the dam will be in the occlusal direction. The positive pressure created under the dam by the tongue and cheeks will force the saliva through the dam contaminating the operative filed. When the edge of the RD is inverted at the neck of the tooth, the positive pressure will keep the fluids underneath the dam.

-An explorer or excavator or any other instrument can be used to tuck the edges of the dam gingivally instead of being occlusally , just move the explorer around the neck of the tooth (around CEJ) facially and lingually with the tip perpendicular to the tooth surface or directed slightly gingivally(apically). A stream of air used along with the instrument passing on the tooth can help with the inversion on the facial and lingual surfaces.

- A floss helps with inverting the dam in the interproximal areas.

Removing the RD

The dentist retracts the dam buccally and cuts it interdentally with scissors.-

-The anaesthetized lip should be protected with a finger.

Finally, the clamp, rubber dam frame, and the napkin are removed.-

-At this stage the dentist should check the rubber to see it is ‘all there’. Any little piece left in the mouth must be removed.

When RD can NOT be used?

1-Partially erupted teeth unable to support a retainer (A clamp with the jaws inclined gingivally is a helpful modification for isolating partially erupted teeth).

2-Some third molars.

3-Extremely malpositioned teeth.

4-Asthmatic patients (they may not tolerate the RD if breathing through the nose is difficult) .

Errors in Application and Removal of RD

1-Off-center arch form

When the holes are punched in an incorrect location, the RD may be insufficient at one corner leaving the oral cavity unprotected and unisolated , allowing foreign matter to escape down to the patient's throat. It might also be obstructing the patient’s nostrils, interfering with respiration.

2-Inappropriate distance between the holes.

-If the distance between the holes is too short, the dam will be overstretched in the interproximal areas which will lead to incomplete isolation(you will see the gingival protruding over the RD).

- If the holes are too far away, excessive dam will be left interproximally, leading to inadequate tissue retraction and makes interproximal access difficult.
3-Incorrect arch form of holes.

-If the punched arch form is too small (incorrect arch form), the holes will be stretched open around the teeth, permitting leakage.

-If the punched arch form is too large, the dam will wrinkle around the teeth and thus may interfere with access.

-e.g. the arch form is U-shaped and the holes is Square! Definitely they won't match!

4-Inappropriate retainer.

An inappropriate retainer may:

(1) be too small, resulting in occasional breakage when the jaws are overspread.

(2) be large, unstable on the anchor tooth.

(3) impinge on soft tissue.

(4) impede wedge placement.

An appropriate retainer should maintain a stable four-point contact with the anchor tooth and not interfere with wedge placement.
5-Retainer-pinched tissue.

It's very commonly seen ,after removing the clamps you will see a huge traumatic gingival , that means you had put the clamp on the gingiva not on the tooth.

6-Shredded or torn dam.

7-Incorrect location of hole for Class V lesion.

8-Incorrect technique for cutting septa.

might cut the gingiva or lips, leave fragments of the dam interproximally.

Other methods of isolation

1-Cotton Roll Isolation and Cellulose Wafers

-Absorbents are isolation alternatives when rubber dam application is impractical or impossible.

-We place them in the buccal vestibules of the upper/lower jaws , we can place them ligually & on the cheek where the parotid duct (Stensen's duct ) is found. In another words , you have to follow the salivary ducts wherever they are and put a cotton rolls there.

-In conjunction with profound anesthesia and saliva ejectors, absorbents provide acceptable moisture control for most clinical procedures.

-Before removing the rolls or wafers you have to make sure they are wet. If they are dry, they will tear the epithelial tissues when removed.

-Cotton rolls should be changed when they become saturated.

-Several commercial devices for holding cotton rolls in position are available. Their use might be inconvenient and time-consuming. However, they might provide slight retraction for the cheeks and tongue, enhancing access and visibility.
2-Throat Shields

-We put (2 x 2 inch) unfolded gauze against the throat of the patient. (over the tongue and the posterior part of the mouth(the end of the hard palate) , don't push it too much). Some people are gaggers , they don't tolerate this method of isolation.

-When the RD is not being used, throat shields are indicated when there is danger of aspirating or swallowing small objects specially when working on maxillary teeth.

-a throat screen is used during try-in and removal of indirect restoration(crows).

3-High-Volume Evacuators and Saliva Ejectors

-High-volume and low-volume evacuator are available. High-volume is better , it has a high quality in suctioning it can even suck the tongue!

-High-volume evacuators are preferred for suctioning water and debris from the mouth because saliva ejectors remove water slowly and have little capacity for picking up solids.

- Svedopter ;- it's a suction ( saliva ejector) and it is the most commonly used tongue retraction device.

- It has a mirror blade like side that is placed in the gingival sulcus.

-It goes on top of the incisal edge of ant mandibular teeth.

-It is clamped to the jaw.

- The hygoformic saliva ejector is less traumatic to the lingual tissues , it has a loop to retract the tongue .

4-Retraction Cord

-Often can be used for isolation and retraction in the direct procedures of treatment of accessible subgingival areas and in indirect procedures involving gingival margins.

-usually used in crown and bridge preparations to retract the gingival away from your margins . In operative procedures, when you want to apply composite to class V cavity (subgingivally) , you retract the gingiva using this device.

5- Mirror and Evacuator Tip Retraction

A secondary function of the mirror and evacuator tip is to retract the cheek, lip, and tongue. This is particularly important when a rubber dam is not used.

6-Mouth Props

-Generally available either as block type or ratchet type.

- The use of a mouth prop may be beneficial to both the operator and patient. The most outstanding benefits to the patient are relief of responsibility of maintaining adequate mouth opening and relief of muscle fatigue and muscle pain. For the dentist, the prop ensures constant and adequate mouth opening and permits extended or multiple operations if desired.

-Used when performing restorative procedures on posterior teeth (for a lengthy appointments).

-A prop should establish and maintain suitable mouth opening, thereby relieving the patient's muscles of this task, which often produces fatigue and sometimes pain.

7-Cheek Retractor

Retract the cheek during esthetic procedures specially for anterior teeth & during taking x-ray .


Rarely indicated in restorative dentistry and is generally limited to atropine which is an anti-cholinergic drug used to decrease salivation.

9-Isolite systemTM

-It's a dental isolation system comfortably retracts the patient’s tongue and cheek, protects the throat, and keeps the mouth gently propped open with continuous suctioning of the dental patient.

-work in upper and lower quadrants simultaneously.

-patient's mouth remains comfortably open all the time.

-light pours in , fluids &debris flow out .

-tow channels of continues , high volume suction keep the working field dry & reduce the oral humidity.

-this device will make your life ,as a dentist, easier.
*if you apply the clamp on the tooth then you put the RD this means you use a wingless one . in case of wings clamp you can either allow the attachment of the dam along with the clamp at the same time or apply the clamp then the RD , the 1st method is easier and more commonly used.
There was a video at the end of the lecture that summarizes the steps of RD application & the doctor said ,that we will have a practical exam in applying RD to the patient at the beginning of the next year Insha'allah……. Best of luck  

Written by :- Eman Ghaleb .

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