Endodontics: Part 6 Rubber dam and access cavities

By Carrotte P1

Date: 01/2004
Journal: Br Dent J


Rubber dam

•Its use is mandatory in modern endo practice because :

1.Aseptic operating field

2.Facilitates the use of strong medicament necessary to clean the root canal system.

3.Protects the patient from the inhalation of endodontic instrument.(Fig1).

•Research has shown1 that rubber dam used during routine conservation procedures reduces aerosol contamination and cross-infection by up to 98.5%.

Rubber dam clamps

•Clamps are described as being either

1.Active -where the jaws slope downwards and positively slide into cervical undercuts. OR

2.Passive -when they tend to remain where placed. •They may also be either winged or wingless, depending upon the chosen method of application. (Fig 6) •The size 8A clamp is described by the manufacturers as a .universal retentive molar clamp • •Small voids around the dam may be sealed with a caulking agent such as Oraseal or Cavit. (Fig9)


•There are three standard methods of application,

1.Winged technique (all in one)

2.Wingless technique ( clamp 1st then RD)

3.Rubber first (RD 1st then clamp)


1.The broken down tooth

•Build up the tooth before

•Electrosurgery or a surgical blade when ginival tissue is encroaching the margin.

•Orthodontic extrusion.


•Bridges do not present a problem with the application of rubber dam.

•A suitable winged clamp is fitted onto the abutment tooth and the dam stretched over the clamp.

3.Split Dam (Fig. 16)

•Slit cut between the holes made for the two adjacent teeth. It is essential that the caulking material is applied to prevent leakage and contamination.

These procedures should be carried out prior to commencing the root canal treatment.

These procedures should be carried out prior to commencing the root canal treatment.


•Before commencement of root canal treatment, the tooth must be prepared as follows:

1. All caries and any defective restorations should be removed and made good. The tooth should be protected against fracture during treatment. 2.The tooth should be capable of isolation.

3.The periodontal status should be sound, or capable of resolution.

•If there is a danger of fracture of the coronal tooth structure, the cuspal height should be reduced to prevent this.

The objectives of access cavity preparation are to:

1.Remove the entire roof of the pulp chamber so that the pulp chamber can be debrided.

2. Enable the root canals to be located and instrumented by providing direct straight line access to the apical third of the root canals.

3.Enable a temporary seal to be placed securely in order to withstand any displacing forces.

4.Conserve as much sound tooth tissue as possible and as is consistent with treatment objectives.