All it takes to put a damper on a day in my practice is finding an open margin on radiographs for a recall patient, when I know I did the restoration. The cascade of emotions and thoughts I am sure are loud enough for both the patient and hygienist to hear even when I am not speaking. There is not much that is more disheartening. In tomorrow’s post I will talk about the balance between our priorities in practice and how e manage them in these situations. One of the most important things I have discovered over the years is that whenever I am uncomfortable, there is great learning to be had. Despite the instinct to explain it away, I have made a commitment to myself to step into the situation. One of the things I want to do is ask myself what I could have done such that this wouldn’t have happened.
What feels overwhelming in these situations, is the magnitude for both the patient and I of now scheduling time and going through the procedure of cutting off the restoration, re-preparing the tooth and fabricating a new restoration. I have spent quite a bit of time analyzing the way in which I prepare teeth, gain retraction and take impressions to minimize the incidence of open margins. Even with all of that, I am clear from time to time the factors will align such that the restoration that comes back from t e lab does not fit the tooth precisely enough. Given this I asked myself the question of what I could do to catch these situations prior to the cementation. Recently we started routinely taking a radiograph at the seat appointment prior to the final bonding or cementation. After the restoration has been tried in, margins checked and the contacts perfected we take an image. We have the patient biting lightly with a cotton roll between the restoration and the Rinn instrument to hold it in place. It doesn’t make it fun to tell a patient that their new restoration doesn’t fit and we need to take another impression, but it is far better than having that conversation after cementation. It demonstrates to our patients the extent that we are committed to their health and the quality of what we do, instead of as an oops!
HATE that. i take a post op of every restoration i seat to verify. i don’t bother to take a “fit” image at try in as i know i have nailed my margins digitally in less than 2 seconds. i also do not cure the bonding agent when i place it on prep so it does not pool into a corner and set keeping me from sitting the restiration all the way…. oh man, to count the number of ways things can go wrong here is exhausting…. thanks for bringing it up
oh, and i just monitor these until they are ready to be replaced, which is at 5 years + 1 day after i placed it :) <<<<<<————– my favorite dental joke right there
My sympathies are with you, it has to be disheartening to see a radiograph come back with the obvious evidence someone in the process dropped the ball. If more dental technicians saw these, maybe they would understand the importance of maintaining the dies throughout the fabrication process. Those of us who have – are generally more meticulous about how we do things. I know I trim all our dies under a scope. I see where the margin is or I send it back to the clinician for a new impression or for him or her to trim the die.
Once we have a die – we see to it it is preserved and the crown fits it perfectly. But the hard cold reality is this – that is as far and as much as we can do. We can make crowns and bridges fit the dies – we have no control or knowledge whether it comes anywhere close to what the patient’s oral condition may be.
Most of the technicians I have known over my 35 years in this profession are meticulous and try their best to give you what you need. I’m afraid though the standard has dropped to whether a restoration will last the 5 years before the insurance will partially pay for its replacement.
I’ve heard assistants tell me they are instructed to blame the lab for anything that goes wrong – we’re not there to defend ourselves after all and it diffuses the anxiety. So we live with two black eyes most of our working life – whether we deserve it or not.
In the second radiograph, the two restorations seem to have open margins that are equally open most of the way around what you can see. This indicates they aren’t fully seated – as if the cement set up before the crown was down. Usually a poorly fabricated restoration or one where the impression wasn’t totally accurate has an open margin that is only open in one area.
Let me ask a question – after seeing tens of thousands of impressions over the years, what are we to do? Less than 10% – maybe 20% at the most were “perfect” – where the margins were clearly visible and a crown could be fabricated on the untrimmed die. The rest… well you know the story. I returned some dies to the dentist to trim, and was refused and told to “do the best I could and go ahead and make the crown.” When I quit the dentist, he claimed it was because i was more interested in making money than serving the patient and I got a nasty letter stating as much. We move on and look for better dentists.
What does the patient do? Wait 5 years and repeat the process?
If it’s digital turn off the clearvu and see how it looks.. There was an article in JPD in the last year talking about crown margins appeared open but it was an artifact of the clearvu option in Dexis
Hello
Seen your post and wanted to pick your brain !
We’ve been having a run of open margins here lately .. good impressions , clear margins , nice fit of crowns from the mill .. YET … radiographs keep showing open margins .. and no open margins at all on nice clean dies .. any ideas how to approach doctor would be appreciated
I have notice open margins on digital x rays and I feel that the penetration of digital x rays do not accurately record dental while accurately records ceramic crowns since there is less absorption of dental digital x rays
Comment please
Jlcaruso
Prosthodontist chicago
The margins should appear sealed, and I highly recommend a radiopaque resin based cement for our all ceramics. To me there is a difference between an open margin, and black space and the radiopacity issues that look more like burnout.
I feel the same
Open margins can be a real pain sometimes with crowns. It can happen with a bad final impression or with a good final impression. If the lab tech over polishes the margins on the crown then you can sometimes get a gap that can be mitigated with finishing the margins. I usually use a 7901 fine carbide or a yellow strip fine diamond to finish margins.
Dear Dr. Brady,
This is an important topic for all dentists and I want to thank you for writing about it. As a dentist who is a ceramist, I have developed some thoughts on the topic. In general, I try to Seth the scene for a very smooth interface between the crown and the preparation nd adjacent teeth. I create less retention form, compared with PFM preparation (10-12). I make sure preparations are finished with fine diamonds and make sure they draw to one another and to the adjacent teeth. The adjacent teeth should be studied for adequate inter proximal contacts to create a pathway for delivery against them. The preparations should have horizontal width that provides a single pathway for delivery. Finally, anterior teeth must be fitted by the hands and finger pressure by the dentist and not by biting, as anterior teeth have lateral loading forces which may create and open margin.
Thanks for another well thought article!!
Are most of dentists honest about the open margins and tell the patient the truth and redo the crown? I was a assistant for 30 years and I have seen it go both ways. It’s very unfortunate for the patient if it is not redone.
Curious as a patient: if a permanently sealed crown does need to be redone, how often can it be safely removed from the tooth without additional damage?