How long does it take to make a single unit crown?

[Jason D]

How long does it take to make a single unit crown? So this question came up in another forum, and I would love to dissect this answer from a variety of folks.

Some ground rules for playing: if someone does it faster you cannot accuse them of “slapping out crap”. If someone does it slower you cannot call them “incompetent for being so slow”

Apples to apples comparison of products, and be able to break down your time.

For example:
Single unit posterior monolithic zirconia from a physical impression with simple instruction (#19 fcz shade a3. For example)
These numbers assume the case is part of a batch (not mixing a bowl of stone for a single impression for example)
Labor time 45 mins
12 mins models
3 min scan
6 min design
8 min cam (importing, nesting, loading unloading, green state, loading sintering oven and matching after sintering)
10 min fit and finish (adjust contacts occlusion margin, fit to solid model)
2 min glaze and stain
4 min blast steam Qc

Does not include logistics or communications.

It’s not a contest and it’s not to tell someone else they are wrong, it’s to better understand that massive variations in methods and expectations.

Anyone want to share?

 

[CoolHandLuke]

assume the case is part of a batch

this is problem comrade.

45 mins labour doing what. and how many other cases are on the table? do you have any timeholes? for example is the plaster room run by one guy who also has to articulate 6 waxup cases, a dozen ortho models, and do dupes and a captek? if so, you wont see your single until the end of the day.

so then, if its next day, how many other cases does your scan monkey do? does this person also nest and cam or is that someone else? given the fact that no matter if the case was milled at 10am or milled at 3pm, the sintering oven will need to be full before beginning its overnight cycle, so its going to come out next day.

now, next day how many other units does the finisher have, and is there a QC check before going to the glaze stage? if there is, is this QC check also doing things like trimming dies, finding bites, and checking finished work out of the porcelain, gold, and denture depts? is this person sitting on units so that the ceramists arent bombarded with units and tempted to finish more units per day so they get paid more? if so, count on this thing sitting in the queue as long as possible, about 2 days before deadline.

now, does the porcelain department also bitterly complain that all the preceeding steps got the wrong bite and now the case needs internal remake?

if so, turnaround is now 2 days.

 

[PRO ARTS DL]

I think hes speaking of actual hands on time. Whatever happens in between or how many you're doing at a time does not account to that and does not matter.

I'd put our times somewhere like this.

12-15min models
15 min scan/design
8 min cam (importing, nesting, loading unloading, green state, loading sintering oven and matching after sintering)
10 min fit and finish (adjust contacts occlusion margin, fit to solid model)
5 min glaze and stain
3 min blast steam QC

Total 56 min.

Of course this is done in the span of about 2 days maybe 3 depending on whatever else goes throughout the day.

 

[Jason D]

this is problem comrade.

45 mins labour doing what. and how many other cases are on the table? do you have any timeholes? for example is the plaster room run by one guy who also has to articulate 6 waxup cases, a dozen ortho models, and do dupes and a captek? if so, you wont see your single until the end of the day.

so then, if its next day, how many other cases does your scan monkey do? does this person also nest and cam or is that someone else? given the fact that no matter if the case was milled at 10am or milled at 3pm, the sintering oven will need to be full before beginning its overnight cycle, so its going to come out next day.

now, next day how many other units does the finisher have, and is there a QC check before going to the glaze stage? if there is, is this QC check also doing things like trimming dies, finding bites, and checking finished work out of the porcelain, gold, and denture depts? is this person sitting on units so that the ceramists arent bombarded with units and tempted to finish more units per day so they get paid more? if so, count on this thing sitting in the queue as long as possible, about 2 days before deadline.

now, does the porcelain department also bitterly complain that all the preceeding steps got the wrong bite and now the case needs internal remake?

if so, turnaround is now 2 days.

I would’ve thought it is obvious, But perhaps not:I’m talking about labor time

 

[CoolHandLuke]

i dont see how a discussion of that kind of hands on time is relevant or useful, but ok, fine. generalizing 2 minutes here, 5 minutes there devalues the actual labour involved to the point of trivializing. its 5 important minutes. can be worth it to spend 6 to get a nicer product. probably not ok to crack the whip on getting down to 4. and you get a complex margin suddenly its important to have 6 instead of 4.

so yeah i dont get it.

 

[CoolHandLuke]

case in point, you want an anterior, monolithic, and have marked 2 mins for glazing.

in reality no ceramist will be happy doing that. 8 hours and 12 photos and maybe you get pretty close match for shade. but no, far far faaaar from 2 minutes.

 

[rkm rdt]

I can eliminate 12 minutes for the model work and the 8 mins for loading the milling machine and the cam stuff.
Therefore I win.
Bow to your Canadian overlord you peons!

 

[Jason D]

I would’ve thought it is obvious, But perhaps not:I’m talking about labor time

i dont see how a discussion of that kind of hands on time is relevant or useful, but ok, fine. generalizing 2 minutes here, 5 minutes there devalues the actual labour involved to the point of trivializing. its 5 important minutes. can be worth it to spend 6 to get a nicer product. probably not ok to crack the whip on getting down to 4. and you get a complex margin suddenly its important to have 6 instead of 4.

so yeah i dont get it.

well obviously it’s relevant because every minute that you spend on something has a value. Each person might find that value to be different, and price of the restoration is (ideally) how you would balance that. In simple terms if you spend twice as Long building value into a product you would hopefully charge more for that value.

Unfortunately in most small businesses, and certainly in our industry, those numbers are relatively arbitrary as each person has their own ideas about what constitutes quality and value.

But I’m not talking about comparing fees, just manufacturing times. This might lead to other questions about methods and reasons...if someone has a particularly high or low time compared to mine for models I would ask which system they use and whether they find the time is justified by the value of the system

It’s about learning and sharing ideas. Most lab owners don’t have the time or desire to visit a lot of other labs to compare notes. I have had some amazing revelations in other labs when I saw something done differently or a tools I had never considered!

 

[Jason D]

case in point, you want an anterior, monolithic, and have marked 2 mins for glazing.

in reality no ceramist will be happy doing that. 8 hours and 12 photos and maybe you get pretty close match for shade. but no, far far faaaar from 2 minutes.

Actually I said posterior and that it was described as a simple a-3 #19

 

[Jason D]

Actually I said posterior and that it was described as a simple a-3 #19[/QUO

case in point, you want an anterior, monolithic, and have marked 2 mins for glazing.

in reality no ceramist will be happy doing that. 8 hours and 12 photos and maybe you get pretty close match for shade. but no, far far faaaar from 2 minutes.

well we are talking about measuring time, if we want to talk about what a ceramist may or may not want, that’s a different thread.

 

[Jason D]

I think hes speaking of actual hands on time. Whatever happens in between or how many you're doing at a time does not account to that and does not matter.

I'd put our times somewhere like this.

12-15min models
15 min scan/design
8 min cam (importing, nesting, loading unloading, green state, loading sintering oven and matching after sintering)
10 min fit and finish (adjust contacts occlusion margin, fit to solid model)
5 min glaze and stain
3 min blast steam QC

Total 56 min.

Of course this is done in the span of about 2 days maybe 3 depending on whatever else goes throughout the day.

Cool, do your scan/design techs scan and design simultaneously or do you have dedicated scan techs and dedicated design techs?

 

[kimba]

I'll play

models 20 mins
scan design 15 mins
nest 10 mins
presinter stain 10 mins ( includes trimming and cleaning of green state crown)
fit finish 10 mins
stain and glaze 10 mins
clean and QC 10 mins

in fairness, I was thinking about a standalone crown. batching would reduce this (maybe 10 percent ?)
I always try to be conservative in my estimations , as in my hands , things are never done as quick as you think they should, so I round up.

Its a good and valid conversation Jason D , thanks for starting it

 

[sidesh0wb0b]

How long does it take to make a single unit crown? So this question came up in another forum, and I would love to dissect this answer from a variety of folks.

Some ground rules for playing: if someone does it faster you cannot accuse them of “slapping out crap”. If someone does it slower you cannot call them “incompetent for being so slow”

Apples to apples comparison of products, and be able to break down your time.

For example:
Single unit posterior monolithic zirconia from a physical impression with simple instruction (#19 fcz shade a3. For example)
These numbers assume the case is part of a batch (not mixing a bowl of stone for a single impression for example)
Labor time 45 mins
12 mins models
3 min scan
6 min design
8 min cam (importing, nesting, loading unloading, green state, loading sintering oven and matching after sintering)
10 min fit and finish (adjust contacts occlusion margin, fit to solid model)
2 min glaze and stain
4 min blast steam Qc

Does not include logistics or communications.

It’s not a contest and it’s not to tell someone else they are wrong, it’s to better understand that massive variations in methods and expectations.

Anyone want to share?

it takes you 12 minutes to make a working and opposing model? come.....on.....now.....so youre saying a 1 person lab should be churning out 10/11 zirconia crowns a day? i think your numbers are off. significantly. dont believe me? grab a timer and all day when you start and stop something, time it. i promise you those numbers are not accurate. (i have timed it in more than one lab, including my own)

 

[Jason D]

it takes you 12 minutes to make a working and opposing model? come.....on.....now.....so youre saying a 1 person lab should be churning out 10/11 zirconia crowns a day? i think your numbers are off. significantly. dont believe me? grab a timer and all day when you start and stop something, time it. i promise you those numbers are not accurate. (i have timed it in more than one lab, including my own)

Sure, that’s part of the interesting discussions we come up with by examining other methods and tools...a quad triple tray monotrac batch is easily in the 10 min/arch range. As I said this first example is to compare the simplest possible restoration.

And no, I would not expect a single person to do 10 in a day....they would have to switch tasks so many times during the day and every mistimed oven cycle or drying time would cost minutes...I would be surprised to see a single person get over 8 mono zinc per day (assuming they could even dictate the incoming product so they could do simple singles all day which we can’t.)

 

[PRO ARTS DL]

it takes you 12 minutes to make a working and opposing model? come.....on.....now.....so youre saying a 1 person lab should be churning out 10/11 zirconia crowns a day? i think your numbers are off. significantly. dont believe me? grab a timer and all day when you start and stop something, time it. i promise you those numbers are not accurate. (i have timed it in more than one lab, including my own)

We use artimax articulators and the times are really not off. Super simple to do and time saving since you forget of pouring a base and pinning models

 

[PRO ARTS DL]

Cool, do your scan/design techs scan and design simultaneously or do you have dedicated scan techs and dedicated design techs?

Scan and design simultaneously

 

[sidesh0wb0b]

Sure, that’s part of the interesting discussions we come up with by examining other methods and tools...a quad triple tray monotrac batch is easily in the 10 min/arch range. As I said this first example is to compare the simplest possible restoration.

And no, I would not expect a single person to do 10 in a day....they would have to switch tasks so many times during the day and every mistimed oven cycle or drying time would cost minutes...I would be surprised to see a single person get over 8 mono zinc per day (assuming they could even dictate the incoming product so they could do simple singles all day which we can’t.)

if i may pry....how many techs do you have working in your lab, and how many crowns per day are they putting out?

 

[sidesh0wb0b]

We use artimax articulators and the times are really not off. Super simple to do and time saving since you forget of pouring a base.

ive never liked monotrac or artimax. so i still do the old school poured bases. that def adds time.
scan times seem reasonable for both of you. i can scan and design a single bicuspid or molar in about 6-8min. (even took vids to prove it awhile back)

 

[CoolHandLuke]

ive always had issues scanning bites in triple trays, its a huge pain.

 

[PRO ARTS DL]

ive never liked monotrac or artimax. so i still do the old school poured bases. that def adds time.
scan times seem reasonable for both of you. i can scan and design a single bicuspid or molar in about 6-8min. (even took vids to prove it awhile back)

I've tried both and then just settled with Artimax. I prefer the pins. I've done full arches with Artimax with every single tooth pinned with no issues. I feel like I couldn't do that with monotrac since the sections can only be so thin before they just move around and lose integrity closer to the base.

The system is definitely aimed towards the Doctor sending a triple tray but even if you get single quads you can easily pour with no issues and still with better timing than pouring a base.