Intraoral scanner crown margins

[doug]

how many microns is adequate for an accurate restoration to be fabricates. Who did the study?

 

[bigj1972]

how many microns is adequate for an accurate restoration to be fabricates. Who did the study?

You know who......

 

[HonestAbe]

Has anyone here made much progress with digital "trimming" or repairing of bad scans? We had one come in the other day with some of the margins covered and a few holes here and there from a particularly hard prep where the patient couldn't open much. I was able to fix the holes in the .stl but the covered margins (something that could be invented/fixed/trimmed away in stone) was a struggle.

I did the best I could with it and from what I understand it seated fine but I got the feeling while flailing around with the meshmixer tools that someone out there has probably mastered things in the same way a highly experienced tech can trim dies from bad impressions well. It feels like one of those things that'll take a lot of hours with the tools to really be effective at.

 

[TheLabGuy]

Has anyone here made much progress with digital "trimming" or repairing of bad scans? We had one come in the other day with some of the margins covered and a few holes here and there from a particularly hard prep where the patient couldn't open much. I was able to fix the holes in the .stl but the covered margins (something that could be invented/fixed/trimmed away in stone) was a struggle.

I did the best I could with it and from what I understand it seated fine but I got the feeling while flailing around with the meshmixer tools that someone out there has probably mastered things in the same way a highly experienced tech can trim dies from bad impressions well. It feels like one of those things that'll take a lot of hours with the tools to really be effective at.

Yep, we made progress...we hit the "reject" button in the software. Then we call the Doc and let the communication train of a good scan and the importance of refraction and isolation begin.

 

[HonestAbe]

Yep, we made progress...we hit the "reject" button in the software. Then we call the Doc and let the communication train of a good scan and the importance of refraction and isolation begin.

I wish I could do that, but I'm not a lab owner, I'm the low man on the totem pole doing the best I can with what I got. If the doc says "do what you can" and the boss says "see what you can do" then that's what I'm going to do because I don't really have another option. I wish it was different but it is what it is.

 

[TheLabGuy]

I wish I could do that, but I'm not a lab owner, I'm the low man on the totem pole doing the best I can with what I got. If the doc says "do what you can" and the boss says "see what you can do" then that's what I'm going to do because I don't really have another option. I wish it was different but it is what it is.

Time to have a heart to heart with the boss then, with all these new docs getting into digital you really have to re-teach them per say on what is good for the lab and what isn't. We do it here and have become comfortable doing it because we work with the dental school, so we get a new group every year and it's the same song and dance. We reject them if we can't see a defined margin, skin tags, cord laying over margin, too much saliva blurs out the margin, etc. Then we even go as far as charging an extra $5 for cleaning up there scan if there is data noise all over the place. Scanning is faster and a ton easier but there is a learning curve too it...and we don't mind that but we don't let them learn with doing remakes. That dragon gets slayed before it enters this cave.

 

[HonestAbe]

Time to have a heart to heart with the boss then, with all these new docs getting into digital you really have to re-teach them per say on what is good for the lab and what isn't. We do it here and have become comfortable doing it because we work with the dental school, so we get a new group every year and it's the same song and dance. We reject them if we can't see a defined margin, skin tags, cord laying over margin, too much saliva blurs out the margin, etc. Then we even go as far as charging an extra $5 for cleaning up there scan if there is data noise all over the place. Scanning is faster and a ton easier but there is a learning curve too it...and we don't mind that but we don't let them learn with doing remakes. That dragon gets slayed before it enters this cave.

Right but imagine the lab has been accepting the same issues with pvs impressions for decades, and accounts are totally used to the lab just trying their best. In principle I fully agree with you, but even having the heart to heart won't fix it if their minds are made up. If they think they'd lose accounts over it or damage relationships then it's just not going to happen.

There exists a whole world out there of docs that can't or won't give the lab what the lab needs to do the best job possible. Again... I fully agree with you that it would be worth pushing back hard on a lot of stuff instead of just trying to make it work, but that's not something I personally can do. I see how difficult it is to run a small business and I don't want to run a lab even if it would allow me to stick to my guns when it came to what cases I would accept doing.

 

[TheLabGuy]

Right but imagine the lab has been accepting the same issues with pvs impressions for decades, and accounts are totally used to the lab just trying their best. In principle I fully agree with you, but even having the heart to heart won't fix it if their minds are made up. If they think they'd lose accounts over it or damage relationships then it's just not going to happen.

There exists a whole world out there of docs that can't or won't give the lab what the lab needs to do the best job possible. Again... I fully agree with you that it would be worth pushing back hard on a lot of stuff instead of just trying to make it work, but that's not something I personally can do. I see how difficult it is to run a small business and I don't want to run a lab even if it would allow me to stick to my guns when it came to what cases I would accept doing.

I can relate and understand you totally. I even understand the owner thinking like that as well but letting a problem exist will only fester and massatize. I can relate because I use to be of the same mindset. Then I finally addressed the problem and created some nice photo explanations to show them the differences (which is easy in the digital realm) and presented it to the Docs. Then a transformation happened where the little ole lab techs were asked if this looks great and asked our feedback. Believe it or not, Docs want to learn...it's in their DNA, just look at how much schooling they went too...it's up to us to be willing to teach them.

 

[Car 54]

Right but imagine the lab has been accepting the same issues with pvs impressions for decades, and accounts are totally used to the lab just trying their best. In principle I fully agree with you, but even having the heart to heart won't fix it if their minds are made up. If they think they'd lose accounts over it or damage relationships then it's just not going to happen.

That's the fine line, in knowing the accounts and how far you can push it, push them, especially if the labs been "making things work" for all those years, can become, "what's happened, why the problem and issues all of a sudden"? Digital has taken it to another level of now having to manipulate a file, compared to faking in a margin on a stone cast from a PVS impression.

 

[Car 54]

.........Then I finally addressed the problem and created some nice photo explanations to show them the differences (which is easy in the digital realm) and presented it to the Docs......

Bingo

 

[HonestAbe]

I can relate and understand you totally. I even understand the owner thinking like that as well but letting a problem exist will only fester and monopolize. I can relate because I use to be of the same mindset. Then I finally addressed the problem and created some nice photo explanations to show them the differences (which is easy in the digital realm) and presented it to the Docs. Then a transformation happened where the little ole lab techs were asked if this looks great and asked our feedback. Believe it or not, Docs want to learn...it's in their DNA, just look at how much schooling they went too...it's up to us to be willing to teach them.

That sounds promising. I can just take the initiative and get the screenshots/explanation ready and present it, worst they can say is "no we don't wanna pass that on" which is highly likely to be the outcome but at least I can say I tried right?

 

[TheLabGuy]

That sounds promising. I can just take the initiative and get the screenshots/explanation ready and present it, worst they can say is "no we don't wanna pass that on" which is highly likely to be the outcome but at least I can say I tried right?

Absolutely bud, any half way decent lab owner will jump on board. Make your first presentation 'screenshot/explanation' to your Boss and sell it to him like you would your Doc.

 

[Car 54]

Nice back and forth, you two

 

[kimba]

come on , one of you throw an insult in . lets get back to how it's seemed over the last few months!!

 

[Pronto]

We have also have sent screen shots of bad margins and clearance problems. Then when they bitch about it we have ammo to cover our ass. Once they see the problem, some will retake or reprep but the ones that won't will get a remake charge when it inevitably comes back.

 

[Jack_the_dentureman]

how many microns is adequate for an accurate restoration to be fabricates. Who did the study?

You know who......

Maybe I didn't get the irony, but I will answer

Less than 120 µm is acceptable
according to the American Dental Association.

usually our crowns have a marginal gap of 27 to 90 µm

 

[bigj1972]

So the ADA says 120 µm ??? Well I guess we don't need all these new single digit scanners and double digit printers.
I knew it was a scam!!

 

[Car 54]

And I believe an explorer tip is ~100 microns, so they never really feel a margin (gap) below that number.

 

[HonestAbe]

And I believe an explorer tip is ~100 microns, so they never really feel a margin (gap) below that number.

What about phantom margin syndrome? Or Schrodinger's margin? If you never feel the margin with the explorer, is it open, closed, or both at the same time? Does measuring it change the outcome?

 

[Pronto]

120 or more is for Drs that mill their own crowns.