Cotton pellets in endodontic accesses

Cotton-Cavit-Fuji IX
Cotton-Cavit-Fuji IX
Cotton-Cavit-Fuji IX

These steps were drilled into me in dental school when sealing up endodontic accesses for multi visit treatment however there are several flaws with the method. The rationale behind this method is as follows:
-The cotton pellet acts as a spacer to stop hard setting materials from entering the root canals. It also allows easy removal of the temporary restoration as you do not have to be instrumenting right down o the pulp floor every time you reaccess
-Cavit has been shown to produce a reliable seal when used in increments of 2mm. This is because it is a gypsum material and will expand slightly on setting in contact with moisture.
-GIC: GIC is relatively inexpensive and can be used over Cavit in cases where the restoration must stay in place more than a few days. This is because the hardness of Cavit is relatively low and it will easily be abraded away in day to day function.

The Cavit-GIC combination is useful in providing a long lasting hermetic seal. However there are multiple issues with the use of a cotton pellet.
-On reaccessing, once hitting the cotton pellet with your bur it will tend to get caught around the bur and can be difficult to remove. You can get around this by using an ultrasonic scaler to clear the cavit.
-It tends to hold water, so if you were to use water in the cavity before the cavit has sealed properly (e.g using a damp pellet to compact the Cavit) it will tend to hold water and wash out or dilute any medicaments you have placed in the canals.
- Cotton pellets are fibrous and will have stray fibres that can become embededd in the cavit. These can act as pathways for oral fluids to track down through the cavit. They can be hard to spot and can even track all the way to the cavo surface margin. This will provide microscopic pathways for bacteria to enter and reinfect the root canals.
-The wrong sized pellet can be used especially in anterior teeth which tend to have large canals and short accesses. Too large and it can reduce the amount of cavit that can be placed in the cavity. Remember, enough bulk is required for an adeuqate seal. If it is too small it may dislodge down one of the root canals and be very difficult to retrieve. I have had to fish out a cotton pellet from near the apex of an upper incisor and it is not very easy to do so.

Some alternative solutions are:
-Do not use the cotton pellet. Pack cavit down the chamber and use GIC over the top. This allows plenty of bulk of cavit to be used and removes the risk of cotton fibres allowing leakage. Cavit can easily be removed from the pulp chamber with the use of an ultrasonic scaler. You must be careful not to pack the canals with the Cavit. Ideally your medicament will occupy the space in the canals to avoid this. However, ultrasonic scaling as well as agitation from hand files under irrigation can remove Cavit from canals fairly easily. Cavit is much easier to clear from canals than a hard setting material e.g resin or GIC.
-Use teflon tape rolled into a ball: These are compactable and can be placed at the floor of the pulp chamber fairly easily. They are hard once compacted and are less likely to fall into a canal. They have no fibres that can lead to leakage and do not hold moisture that can wash out medicaments. Different colourse e.g pink or blue can be used to distinguish them from the Cavit.

My current protocol is:
1. Place medicament
2. Pack cavit in bulk at least to the height of the pulp chamber/ Ensure all sides of the cavit is sealed againt the tooth.
3. Use a slow speed bur or high speed bur with water spray to clear the excess Cavit on the cavity walls. An ultrasonic scaler used here will agitate the cavit and dissolve it very quickly which is not ideal.
4. Condition the cavity and place a GIC as normal