Perforations and How to Avoid Them

Written by Dr Lily Dogmetchi BDS

Let’s set the scene…

A few months into my DFT year, a new dentist’s worst nightmare happened to me… I perforated a tooth during a root canal… and it was a bad one…

I was treating the LR5 on a 25 year old phobic patient and unfortunately I got my angulation wrong when drilling. When the access cavity started to fill with blood I assumed it was because of pulpitis. I should have dressed and temporised the tooth because the blood restricts your vision. However, I was keen to carry on and tried to find the canals without being able to see at all (don’t do this, it was a terrible idea). I managed to get a file in what I thought was a canal and started doing some light orifice enlargement (little did I know I was about to make the problem worse).

When I took the working length radiograph and saw that not only had I perforated, but it was the worst perforation I had ever seen… It felt like the rug had been pulled out from under me and my first reaction was to curl up into the foetal position in the corner.

My ES and the other dentists were all in AGP sessions and I was truly on my own with no one to help me.

So, what happened..?

Explaining to the patient what happened was absolutely mortifying and I waited absolutely terrified to how he would react…. Luckily he was absolutely lovely about the whole situation and we had discussed perforations as part of the consent procedure, so it was less of a shock to him.

The patient opt-ed to have the tooth extracted which I decided to do that session as I wasn’t sure how to temporise a perforation that severe. The extraction was completed uneventfully.

On inspection of the extracted tooth, you could see the perforation occurred at the margin of a subgingival restoration (watch out for those when doing RCTs!)

The next scary part was explaining what happened to my ES later that day, to my relief she was nothing but reassuring and explained that she has done it herself more than once, and it was nothing to upset myself over.

The most important lesson I learnt: don’t be afraid of messing up! I know as a dental student or a new dentist, we all fear perforating, breaking files, breaking teeth during an extraction, crowns not fitting or drilling a tooth without caries. I’m here to tell you I have done every single one of those things in my DFT year (except breaking a files, but the night is still young!) and each experience has made me a better dentist, I have learnt from ever experience and now I know:

•     How much pressure to apply when extracting teeth and how much with break it

•     I know how to extracted retained roots and I am so much more confident in my surgical skills (because I have broken a fair number of teeth!)

•     I know what is feels like when a file is in a canal or perforating out the side of a tooth

•     I know what’s fissure staining and what’s fissure caries

I know all these things now because I made those mistakes. It’s better to make those mistakes early on when you have the support of your supervisors to show you where you went wrong and how to fix it. Now, I’m not encouraging you to go and starting perforating teeth, but please don’t be afraid of making mistakes and don’t be put off if you make them! It’s the best way to learn.

Now for the bit you’re actually interested in… how to avoid perforating:

•     NEVER drill your access cavity with a rubber dam on, you will get your angulation wrong and end up with a perforation

•     Get your angulations right! This can be tricky with mandibular teeth. You want to make sure you are drilling down the long axis of the tooth. If you are struggling, pinch the alveolar ridge between your thumb and forefinger, you should be drilling straight down the middle of your fingers.

•     Vision is key! If you can’t see, you can cause so much damage. If there is blood or pus in the pulp chamber, let it drain as much as possible, then dress and temporise and come back to it another day.

•     The pulp chamber floor should be at the level of the CEJ, if you’ve been drilling for awhile and can’t find any canals or the pulp chamber, stop drilling! Take a radiograph and see where you are (this has saved be so many times!)

Final take-home messages:

Never lie or try and cover up what you’ve done. Trust me I know its tempting and the thought did cross my mind. But you have to remember you haven’t done anything wrong! Perforation is a common enough risk that it needs to be included in the consent process. The worst thing that can happen is the patient makes a complaint (which I know doesn’t sound great) but if you explained the risk of RCTs and the patient consents to treatment… the complaint can’t go any further.

Which takes my to my final point. Consent is key. Firstly, it means it’s not a massive shock to the patient if something goes wrong and secondly it means they can’t take any legal action against you (just make sure your notes are bullet proof!).

Authored by Dr Lily Dogmetchi, BDS

@drlilydogmetchi