Inside Dental Assisting
May/Jun 2011
Volume 7, Issue 3

Using the Rubber Dam for Operative Dentistry

Practical tips for the dental assistant to simplify the process for dry field isolation.

Bruce W. Small, DMD; and Sharon Clawges, CDA, RDA

Since its introduction by Barnum in 1864, the use of the rubber dam has improved operative dentistry in many ways. A drier field, better visibility and access, increased patient comfort, and infection control are only a few of the many advantages of using a rubber dam.

All dental schools as well as dental assisting schools teach and require the use of dry field isolation but, unfortunately, most dentists do not use the rubber dam on a regular basis in private practice. One of the reasons is the lack of proper training. This article will address the preparation, application, and removal of the rubber dam and offer practical tips for both the dentist and the dental assistant to simplify and hopefully increase its use.

Preparation of the Rubber Dam

Before beginning the rubber dam application, it is a good idea to explain to the patient what to expect and why it is being used. Many patients have not been exposed to the dam and may not understand or fear its use. Remind the patient that they can breathe and swallow normally or ask for a saliva ejector, which can be placed if necessary. Also prior to placement the dentist or assistant should floss the contacts of the teeth being isolated to determine if there are any tight spots.

Rubber dams come in two sizes, 5 inches by 5 inches or 6 by 6 sheets in latex or non-latex. The six-inch variety gives the operator more room and is easier to use for most operative procedures. The dam is folded and a crease is made to identify the center (Figure 1).

Then, holes are punched for the teeth. Templates are available but "freestyle" punching is preferred because no two mouths are the same. Many times teeth are not in perfect alignment and the holes need to be offset.

If isolating a mandibular quadrant, begin punching for the central incisor on the center line 1.5 inches from the bottom of the dam—if isolating a maxillary quadrant begin 1 inch from the top. This will help ensure that the dam will be in the proper position over the mouth and cover the lips. After looking at the patient's teeth, the remaining holes can be punched usually 3 mm to 4 mm apart using the smallest punch for the anterior teeth, the middle size for bicuspids, and the large hole for molars (Figure 2). The easiest way to create the holes without ripping the dam is to punch and push the hole-puncher through the hole. Make sure that the small rubber circles from previous punching are removed from the wheel on the puncher prior to using it.

To allow easier movement of the dam between the contacts of the teeth, a water-soluble lubricant sometimes helps. These are commercially available from a dental supply company or at a pharmacy as brushless shaving cream. Placing a small amount between the holes with a small cotton applicator can be very helpful when flossing.

Retainer Selection

The next step is to select the retainer (or clamp). Ideally, the tooth to be retained should be the most distal tooth in the quadrant or at least one or two teeth distal to the operating tooth. This placement will give the operator the room to prepare, place, and finish any type of restoration. The retainer should have four-point contact on the tooth and be very stable (Figure 3) and be tried on the tooth prior to placement of the dam.


There are two basic ways of placing the dam. One is to place the retainer on the tooth and then drape the dam over the bow and the other way is to place the retainer and dam at the same time, which most often is easier because the mandible or maxillary tuberosity sometimes may be in the way.

The bow of the retainer is pushed through the dam as is shown in Figure 4. The dam is then draped over and the rubber-dam forceps engages the retainer (Figure 5). This assembly then is carried to the mouth and placed on the tooth and checked for stability (Figure 6). Next the dam is moved under the jaws of the retainer to keep it in place (Figure 7). Before the frame is placed, a rubber-dam napkin is sometimes used to protect the patient from any type of allergic reaction. A non-latex rubber dam can also be used for patients who have any latex allergies.

At this point the frame can be placed, stretching the dam over the mouth and lips. The typical U-shaped metal or plastic frame can be used, or a Woodbury type (Figure 8) can be used, which utilizes straps that go behind the patient's neck to retract the dam (Figure 9).

Using finger pressure, make an attempt to snap the dam through the contacts and floss the most anterior contact first to stabilize the dam. Next, floss the contacts to get the dam below the contacts. A tip here is to come from the buccal or lingual with the floss rather than straight down from the occlusal in order to reduce the resisting surface area.

The final step is to invert the dam using an explorer tip and air from an air/water syringe.


When the procedure is complete, the rubber dam can be carefully removed. First, cut the rubber dam septums with a blunt-edged scissors. Next, place the rubber-dam forceps and lift off the retainer and dam together with the napkin. The napkin can then be used to wipe the patient's face and clean any debris left behind.


There is much to learn about rubber dam and its benefits in operative dentistry; this article only discussed some of the basics. Missing teeth, bridges, and Class 5 applications are other topics not addressed here but should be known to any operative dentist and his/her assistant. Custom adjustment of retainers and the use of various frames are other topics for consideration.

The authors recommend that dental assistants learn as much as they can from others who use the rubber dam often. Other suggestions would be to have a rubber-dam set-up readily available in the operatories (Figure 10) and to use the dam daily on all operative as well as some crown-and-bridge procedures (Figure 11, Figure 12, Figure 13, Figure 14 and Figure 15).

The placement can be a one- or two-person operation but, as a team, a trained dentist or assistant should be able to place a perfect dam in 90 seconds or less.

Using dry-field isolation will allow the dental assistant to be more efficient and make better use of her or his time, help to improve the quality and longevity of the dentistry, and the patients will appreciate the effort being made on their behalf.

About the Authors

Bruce W. Small, DMD
Private Practice
Lawrenceville, New Jersey

Sharon Clawges, CDA RDA
Private Practice
Lawrenceville, New Jersey

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