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Rubber Dam Use During Restrictions

Presenter: Dr Steven Cohn AM
Date of Webinar Recording: 27/04/2020
Duration: 35 minutes

Dr Steve Cohn revisits rapid and simplified rubber dam application techniques for potential restriction scenarios.

It's not always possible to defer Aerosol Generating Procedures (AGPs) under restrictions, especially if your patient needs urgent and emergency dental care that simply cannot wait. This is where the appropriate use of rubber dam for applicable patients can reduce risk, improve patient comfort and minimise the spread of aerosolised saliva and blood.

Effective April 26th 2020, restrictions on dental practices have been amended from Level 3 to Level 2 restrictions.

The techniques of rubber dam application shown in this video are applicable for dental treatments during both Level 3 & Level 2 restrictions.

Click here for the references Dr Cohn mentions in the video

Your Questions Answered

Thank you for the questions submitted to Dr Cohn relating to the Rubber Dam video 'Rubber Dam Use During Restrictions'. We are pleased to provide the answers from Dr Steve Cohn, helping you to become more confident in your use of rubber dam.

Question No.1

How can we apply rubber dam on 16, 55, 65 and 26 for an 8-year-old child that I need to bond brackets to for orthodontic treatment while all 7s are unerupted, and will the child tolerate clamps, just to reduce aerosol?

You have raised a great question about clamp use. If you are treating adjacent teeth (16, 55 for example) I would punch 2 holes or use a cuff. The cuff can be simple in this case. Punch the largest hole for the 16 and stretch it over to include the 55 as well.

My view is that the clamp is the best way to ensure the integrity of the dam. However, if you think the clamp will not be tolerated, I would place the dam and use Wedjets or Fixafloss etc in the distal and mesial contact points. Then I would put some GIC on the distal of the 16 (and maybe on the palatal as well) to lock the dam in place and act as a clamp. I would do the same on the mesiobuccal and maybe the mesiolingual of the 55. Of course, in all cases, the GIC must not interfere with the restoration that is planned. These steps would be especially important if using the cuff.

If you are using 2 holes, I would invert the dam around each tooth with the floss technique described in my presentation. Furthermore, I would consider the ligature technique on both teeth. If you do this, you might not need as much or any GIC-you would have to judge that.
In your clinical notes, I would mention you have used dam. This covers any possible medico-legal issues because there is no clamp. Each clinical situation will be different but hopefully, these suggestions will be useful.

Question No.2

Do you have any tips for placing a matrix band on the tooth that is clamped?

Thank you for your question regarding the rubber dam presentation from ADA (NSW) CPD. Fitting a matrix band on an already clamped tooth can be a challenge. However, may I start by discussing a case where you know you will need a matrix band before you put the clamp on because this will help me reply to your question.

Let’s assume you need to do an MO restoration on a 16. The problem, of course, is how far will the proximal box extend, and will the interproximal dam be in the way. Now you need to consider what clamp you will use. I like a W8A pattern for an upper molar. Its sits well given the rhomboid shape of the uppers. The beaks point downwards so there is more room to push matrix band apically. If you are treating a lower molar, I would be also looking at what is called an unerupted clamp pattern like a W8A or W14A or 14A for the same reason.

Next is the rubber dam. You have two options. First, you can punch two holes and isolate the 16 and 15. I would evert the rubber dam around both teeth with the floss technique shown in the video. Between the 16 and 15 use a wedge to push the dam down apical to where the floor of the proximal box will finish. If you are unable to do this then you need to cut the interseptal rubber dam, essentially creating a cuff. The second option is to do a cuff from the beginning. The cuff can be simple in this case. Punch the largest hole for the 16 and stretch it over to include the 15 as well.

Now to return to your question. Let say you have placed the dam on the 16. You have an occlusal restoration planned but it has become an MO. You can try and stretch the rubber over the 15 and create the cuff. Sometimes this works, but sometimes the dam tears. If that happens, replace the dam with the cuff technique, or put a second dam over the original one as discussed in the video. You may also need to change the clamp as discussed previously. If you have a 17 present, consider clamping this tooth and evert/ligate the dam around the 16. Then there is no clamp to obstruct fitting the matrix band. You may need to wedge one or both contacts.

If you need to do a DO restoration, consider purchasing what is called a distal bow extension clasp. Hu-Friedy makes the 8AD clamp (carried by Henry Schein). This allows access to the distal of molars. This is a great clamp when you need to prepare the distal on the last molar with no tooth behind it to anchor the dam. But as I said your question can be a challenge and some dam applications will be imperfect and maybe even not possible (but I think that is rare).

Question No.3

Please comment on the preference of dam thickness.

Latex dam can come in several thicknesses or weights. Thin, medium and heavy are the most common. The non-latex dam seems to be only available in medium.

Medium is my choice in both latex and non-latex for both endo and restorative. The exception with restorative might be a gingival restoration where more dam eversion and tissue retraction are desirable. I would consider using heavy in this case. Non-latex does not evert as well as latex, but this can be compensated for by punching a smaller hole than for latex.

Question No.4

Is it alright to stabilise the dam with Wedjets only, even for single tooth isolation? I find it very convenient to place and less traumatic than a gingival cuff, especially in a weak tooth.

Yes, I sometimes only use Wedjets to secure the dam to the tooth. Usually, it is with an anterior tooth and when I am looking for a calcified canal. In these cases, I may need to take progressive images to see if I am on the right path with my access. The clamp may interfere with my image. If you have downloaded the references from the website, you will see an example of only using Wedjets in my article on rubber dam hints.

Please remember to indicate in your notes that you have used rubber dam. This is essential for an endodontic case, but I would do it for restorative as well because with no clamp you will have no radiographic proof you did so. I hope this helps, and thanks for your question.

Question No.5

Could you discuss RD placement on a crowded or rotated or submerged the second molar?
We have all had those situations where the clamp pops off teeth without sufficient undercut or less than ideal orientation. Do you have any suggestions if avoiding palatial/buccal local anaesthetic in very anxious patients or needle fear - do you routinely give these injections for rubber dam placement?

The best clamps in my opinion for the molar situation you describe are the unerupted clamps such as the 14 or W14 and 14A and W14A. There are other similar clamps. The beaks point apically and are designed for these situations. The other clamps that may be helpful are the 12A and 13A clamps with serrated beaks that grip the tooth more securely in some cases.

Thank you for pointing out that I did not discuss LA in the video. One of the many omissions! Yes, I do use LA routinely in part because patients believe endodontics is painful and also because clamps on exposed cementum and root surfaces can hurt irrespective of the pulpal status. I think a palatal injection for a clamp can be helped by a few drops of LA in the buccal papillae and introducing the needle this way for the palate. The other thing I like is an intraligamentary injection. However, wish I had a better solution.

Question No.6

If we are using another dam to control the leak due to a big hole, do we have to use two plastic frames? Can’t we just use one?

Sure one frame is fine. I show two to better illustrate the point.

Question No.7

What are the minimum clamps I should have in practice?

Referring to the content of the video and the references on the website this is what I would recommend:
Anteriors: #9 pattern
Premolars: W2 or W2A
Lower molars: 26N
Upper molars: W8A

These 4 clamps will do over 90% of teeth in my opinion. Other useful clamps are:
27N for small lower molars and all premolars.
W1A and 1A wingless and winged clamps for broken down premolars. The beaks point down to engage the root surface.
W14 and 14: wingless and winged clamps for molars.
W14A and 14A: wingless and winged clamps with beaks that point apically to engage a root surface or for partially erupted molars.
12A and 13A: winged clamps with serrated edges to better grip molar teeth.
8AD (Hu-Friedy, from Henry Schein): a distal bow extension clamp for treatment of the distal surfaces of molars.

Question No.8

Can you please make a video on how to isolate a tooth which needs cervical restoration?

Thank you for your question regarding the rubber dam presentation from ADA (NSW) CPD. I agree a video on cervical restorations with rubber dam would be very useful, but while we wait for that here are some points to consider. A cervical restoration in an anterior tooth means you must consider the tissue biotype and aesthetics (the smile line). Medium weight rubber dam may be fine to aid with retraction, but heavy should also be considered. You may need a smaller hole than usual. Use the floss technique described in the video to evert the dam. Consider ligation as well.

Your usual #9 clamp may or may not work-it might not seat far enough apically. A #212 clamp is a similar pattern and designed for cervical lesions. The 212 beaks point downward to engage the root surface. Perhaps the best clamps for gingival retraction are the Brinker clamp series. They are designed to be gingiva friendly and seat further down. The specific ones for anteriors are the B5 and B6. The B5 and B6 are also useful for some premolars. However, the surface area is small, and all these clamps can be unstable and rock from side to side. You should stabilise them with GIC or compound or something similar on the adjacent teeth. If you only have a #9 you can heat up the beaks and bend them apically. You will probably need a clamp that stretches more than the average one as well. That’s why the 212 and Brinker's are good, they have all these features.
In the posteriors, Brinker 1-4 is a good choice. They are made by many companies.

Question No.9

Is latex better than non-latex?

Thank you for your question regarding the rubber dam presentation from ADA (NSW) CPD. I don’t think we can say that latex or non-latex is better than the other. They both have advantages. The main one for non-latex is there is no chance of an allergic reaction (but everything else like latex gloves or instruments that have contacted latex have to be quarantined as well). Some dental schools only use non-latex because of this potential problem. It could become the standard of care for this reason. However, on a personal basis our practice medical history forms reveal a very low incidence of latex allergy. I have been fortunate in never encountering an unsuspected latex allergy, but cases have been reported. In endodontics, it introduces another problem. Gutta-percha can and does cause an allergic reaction in susceptible patients.

Non-latex only seems to come in a medium thickness or weight. It also stretches more than latex so the hole size may need to be reduced compared to latex for better fit around the tooth.

My preference is still latex. It retracts tissue very well for better access. Latex dam comes in at least 3 thicknesses or weight grades (light, medium and heavy). Coltene also has extra heavy and special heavy. I have seen these but not used them clinically. However, supply houses may not carry all these because of demand. Medium is the most useful weight for endo and restorative, with heavy occasionally if you need extra dam eversion for a gingival restoration.