Contacts

Decalcified

Decalcified

Member
Full Member
Ratings
9
#1
after 11 years as a Ceramist I still struggle with contacts. Anybody have a good and fast way to get nice broad (not wraparound) contacts? Is it faster to over build and grind back, or under build and add them last? Any thoughts or tricks? Thanks!!
 
Car 54

Car 54

Well-Known Member
Full Member
Ratings
2,455 28
#2
I prefer to overbuild them a bit, and add a little porc. under the contact area after I remove it from the model. At least if you have to add on this way,
you'll be adding on to a canvas that's pretty much already there, making add-ons less of a struggle. It is still something that at times can take me 2,
sometimes even a 3rd add on during the glaze, depending on the path of insertion. I like, and so do my accounts, broad and deep contacts whenever and wherever I can in harmony with the tissue and emergence.
 
M

Mike Fulton

Member
Full Member
Ratings
14
#3
I agree, overbuild a bit. It's what you do next that matters, concerning sanity at least. Our procedure goes something like this. 1) You need a sectioned model so you can remove the distal section or the mesial section at will and a solid model with the margin ditch out with say a #2P burr. 2) Take out either the mesial or distal section and spot in the one contact, then the reverse. So you have spotted in both contacts individually. Now put the whole model back together and do both contacts at the same time. This will also determine the path of insertion. 3) Last but not least seat the crown on the solid model. In this step don't use any articulating paper just look for the bit of stone left on the crown as you work it down. If you have done step #2 correctly there should not be much to do at this point. If you do open one contact up it should be easy to correct in S&G.
 
ps2thtec

ps2thtec

Well-Known Member
Donator
Full Member
Ratings
923 11
#4
I agree, overbuild a bit. It's what you do next that matters, concerning sanity at least. Our procedure goes something like this. 1) You need a sectioned model so you can remove the distal section or the mesial section at will and a solid model with the margin ditch out with say a #2P burr. 2) Take out either the mesial or distal section and spot in the one contact, then the reverse. So you have spotted in both contacts individually. Now put the whole model back together and do both contacts at the same time. This will also determine the path of insertion. 3) Last but not least seat the crown on the solid model. In this step don't use any articulating paper just look for the bit of stone left on the crown as you work it down. If you have done step #2 correctly there should not be much to do at this point. If you do open one contact up it should be easy to correct in S&G.
I find rubbing red pencil on the contacts is faster and doesn’t have a chance of the gummy build up
of the schmear from articulating paper. ;)
 
sidesh0wb0b

sidesh0wb0b

Well-Known Member
Full Member
Ratings
1,552 29
#5
find a porcelain system that doesnt shrink like crazy. dont try to do everything in one bake.
i always fire as built on the first layer. second layer i hone in on contacts and occlusion. add any remaining tweaks on third bake. nearly spot on with minimal grinding should be the goal.
 
M

Mike Fulton

Member
Full Member
Ratings
14
#6
I find rubbing red pencil on the contacts is faster and doesn’t have a chance of the gummy build up
of the schmear from articulating paper. ;)
Use Accu-Film 1 from Parkel it's only coated on one side put the un-coated side against the stone contact area and you only get a mark on crown. It's 20 Microns thick, red for metal green for porcelain. The film protects the contact area from wear like you can have with the pencil technique, particularly with new techs.
 
P

Polarmolar

Active Member
Full Member
Ratings
48 2
#7
Proper framework design is the best way to get consistent shrink rates. Then I usually overbuild one contact check it on the solid model and then rebuild the other on the glaze bake. Posteriors are usually only two bakes for me and I never check my contacts on sections models and I only check them on solid models in case my model guy missed something. I use foil also because I want it to rip if it's way to tight and it isn't as gummy as other brands I've found. Well that's how I do it and I've found works for me.


Sent from my iPad using Tapatalk
 
TheLabGuy

TheLabGuy

Just a Member
Full Member
Ratings
1,722 34
#9
I use e.max ceram Add-on incisal and dentin for all my contacts...it's a relative low-fusing porcelain and is compatible with most PFM ceramics as well. However, I try to do it in build-up phase, then during finishing (use working model and solid model as others have stated). Even then, you still might get a open contact...use some of that e.max add-on incisal in the glaze phase and then you're done.
 
Guest Room
Help Users
  • No one is chatting at the moment.
  • Chat Bot:
    Room has been pruned!
    Chat Bot: Room has been pruned!