The isolation of the operatory field is the step responsible for obtaining and maintaining a clean and dry field with suitable access- aspects essential to the success of any clinical procedure.

The use of a rubber dam during isolation has numerous benefits :
  • First, absolute isolation of the operatory field allows for optimal control of contamination and moisture, which is essential to the improvement and performance of restorative materials.
  • It also offers increased visibility and access for the professional, allowing procedures to be performed more accurately. This advantage is evident especially during the preparation of cavities with rotary instruments since the high power of the cutting or grinding makes the instrument so efficient that special care should be taken in order to minimize the removal of healthy tooth structure.
  • The absolute isolation of the field also protects the patient against accidental swallowing and aspiration of objects and debris, in addition to preventing accidental injuries to soft tissues.
  • Increasing the operator’s safety, protecting him/her from possible oral cavity infections.
  • Minimizes waste of valuable clinical time, since the patient is unable to talk and expectorate during the procedure
For all of these advantages, it is highly recommended that the absolute isolation should be performed whenever possible.
When is it recommended ?
  • During caries removal particularly in deep cavities.
  • During the removal of unsatisfactory restorations.
  • In all procedures involving amalgam to reduce aspiration or swallowing of mercury by the patient.
  • Throughout all adhesive procedures, whether direct or indirect since the absence of contamination and moisture control are critical aspects for successful adhesion.
  • In situations where access to the lesion or cavity depends on gingival retraction promoted by clamps.
  • In patients with physical impairments or special needs to reduce the possibility of swallowing of instruments and objects.

Contraindications :
  • In patients with asthma or respiratory difficulty, since the rubber dam prevents mouth breathing.
  • In teeth with incomplete erupt, since it may be difficult or impossible to properly invaginate rubber.
  • In patients with a latex allergy, although it is possible to use a latex-free rubber dam.

Components :

Several tools and materials are required. Counting on all items which may eventually be required during isolation is essential so that the procedure can be performed quickly, safely and with minimal discomfort to the patient.

Rubber dam
It is the rubber sheet (dam) responsible for separating the operating field from the oral cavity. It is waterproof and available in various thicknesses. The thicker sheets are more resistant and promote better gingival retraction as well as providing better sealing of the interface between the rubber and the tooth. It is also offered in assorted shades- ideally, dams showing adequate contrast with the color of the dental elements should be used (eg. green or blue). Finally, there are latex-free vinyl sheets that are very useful for use on allergic patients.

Young frame
It is a U-shape metallic device used to grasp and stretch the rubber sheet. For this, it has small claws along its shaft, which maintains the dam slightly stuck-under tension. The frame has a curvature in the central region, which indicates the position to be used- the concave part should face the rubber sheet.

Rubber dam punch
Used for making holes corresponding to each tooth to be isolated. It has a rotating part with five holes of different diameters, each designed for a specific group of teeth.

Clamp forceps
For grasping and opening the clamp, to allow for its placement on the tooth. At the end of the procedure, it is also used in the removal of the clamp. To perform that correctly, it is important that the ends of the active forceps show the proper format in order to firmly grasp the clamp and detach easily at the desired time.

The primary function of the clamp is to maintain and stabilize the rubber sheet, although they are also possibly responsible for promoting the retraction of gingival tissues.
According to the tooth to be isolated and the specific clinical situation, clamps of different designs, shapes and sizes can be used. In restorative dentistry, the most commonly used clamps are:
  • 200 to 205 (molars)
  • 206 to 209 (premolars)
  • 210 and 211 (incisors and canines)
  • W8A and 26 are commonly used, both recommended for the isolation of posterior teeth, especially when they present short or expulsive crowns-situations in which using “conventional “Clamps is quite difficult.
ln fact, the versatility of a #26 clamp being elevated, makes it the first choice for isolation of molars, at least when positioning the clamp prior to the insertion of a rubber dam, as discussed in the next post.

Finally, in situations where it is necessary to retract the gingival tissue, one can use the #212 - as well as its variants 212L and 212R, which are useful when there is the need for the simultaneous retraction of two adjacent teeth. It should be emphasized that, in some cases, it is required to modify the curvature of the lingual or labial jaws of the #212 clamp to achieve greater retraction in one of the surfaces, without causing trauma to the periodontium on the opposite surface. Therefore, when greater retraction in the labial surface is desired, the labial jaw should be curved to the apical aspect and the palatal jaw to the incisal and vice-versa.
To better understand how the modification of the clamp influences the result of the isolation, check the previous post Class V composite restoration
In spite of the fact that the design varies significantly between clamps, it is possible to divide them into two main groups: clamps with lateral wings - this difference is easily observed in the following pictures. This is important when selecting the most appropriate clamps for each isolation technique. As a rule, the technique where the clamp and the rubber dam are inserted simultaneously clamps with lateral wings to attach the clamp to the rubber dam.

Water-soluble lubricant
It is applied to the internal aspect of the rubber dam, directly on the perforations, in order to facilitate passage through the interdental points of contact. ly and can easily be removed with air/ water spray. Vaseline is absolutely forbidden, since it is not soluble in water and is a contaminant, and can compromise the effectiveness of the adhesive bonding.

It is used to mark the position where the rubber dam will be perforated on the mark for each tooth to be isolated. The most effective pen is the wet tip marker, able to mark the rubber even when it is slightly touched or when it is touched with the side aspect of the active tip—a relevant since the marks are made intraorally, with the rubber dam placed over the teeth. Ballpoint pens are not indicated, since they are nor efficient when used at a steep angle -as required for intraoral use- and marks depend on the pressure that the tip makes on the surface.

Dental floss
prior to the execution of the rubber dam isolation is used to evaluate the pressure of the proximal contacts. If they are excessively tight, the contacts must be set before installing the rubber dam in order to allow it to be inserted without difficulty.
Even in the moments prior to the insertion of a rubber dam, dental floss should be used to detect the presence of sharp edges or excess restorative material in teeth with deficient restoration or proximal carious lesions. Generally, where the floss shreds or breaks during the assessment of proximal surfaces, it is recommended that they are adjusted prior to the insertion of the rubber dam-it is important to avoid rupture of the sheet during the insertion. The proximal adjustment can range from mild wear with abrasive strips until the total removal of the restorative material,in the case of teeth with deficient proximal restorations. Besides these tasks, dental floss is interproximal regions, to promote invagination in the space of the sulci so as to stabilize the isolation with loops, as will be shown later. A good quality dental floss with a waxed surface usually facilitates all these procedures.

Abrasive strips
eventually used for adjusting the proximal surface in order to facilitate the passage of the rubber dam-as already discussed.

Blunt tip spatula
assists in the invagination of the rubber dam and in the making of the loops, as will be shown in the step by step sequence.

essential during the step of removing the absolute isolation of the field, cutting the rubber dam and facilitating its removal.