The Art of Baseplates

[araucaria]

The foundation of our work isn't so simple a matter to many techs especially the trainees. Even now after 30 years of being a prosthetics specialist I'm always trying to improve things around the lab, for the benefit of myself and the clinicians. The extra 1% that may be acheived some days always seems worth the effort and I bet we all wish we knew the tricks a lot sooner in our careers.
We make our plates from various materials and try to do what seems best for the job and for the clinical procedures. It may be wax, shellac, coldcuring resin, lightcure, or even thermoformed. For edentulous situations the retention quality is commonly a big issue esp' the upper. To get the retention tested here at try-in stage can be a challenge some days.
TheLC bases while strong, rigid, and uniform in thickness always seem to display signs of distortion. The other materials also seem to deform in some way no matter how small.
The only reliable baseplates for testing the retention qualities IMO is a heatcured permanent baseplate. These add to the workload but give great results. How many times have we received a new impression in a try-in simply because the baseplate wasn't secure due to a minor distortion? Anyone remember ZOE in these? I get reps pushing their LC product onto me saying how wonderful and dimensionally stable they are, yet do these guys have any first-hand experience of the problems that occur. A method that does give good results is using a dual laminate thermformed material but it takes a little practice. Good ol' shellac also works for me in many cases but only used up to the ridge crest and then extended with wax.
The clinical stages do rely on good quality labwork even at the basic levels, and the artwork is of no concern until the foundation of the job is reliable.
The one thing I've yet to try is to have a model scanned and a resin pattern printed - surely it can't get better than that?
The baseplate - so simple, yet forever challenging.
What are your thoughts?

 

[kcdt]

I remember ZOE stabilized baseplates. Processd denture bases are the best, but incure extra labor and charges.
So what exactly do you mean by distortion with LC material? Are you referring to contraction across the palatal vault that causes lift off?
The way to stop that is to adapt the sheet on the model cut out and remove the palatal, cure the rest for a minute, re-adapt the palate , and cure.
I have over the years found this material to be the best choice for a temporary base.
Shellac is crap, and I find it hard to believe they even bother making it anymore.

 

[araucaria]

I like the split curing of the LC base. I think I'm yet to find the right brand and ideal thickness though to prevent small dimensional errors from occuring.
The changes can be simply lifting in the palate, or a general contraction from curing. Sometimes everything's fine and sometimes there are irritating changes. What's your preferred brand?
IMO it's not as stable as I'd like it to be. The texture and taste is something that patients sometimes comment on but I don't see a problem there - it's just something quite different to their dentures.
Shellac is surely something from the ark, but there are brands that are useful.
I'm always trying to find ideal/best solutions for the different situations we're faced with. We don't have a "ones size fits all" answer to what we do, so that's where I'm coming from when asking for thoughts and opinions based on folk's experiences in their lab life. Even if I don't pick up any hints, there may be somebody else looking at this board who'll find an answer to a problem.

 

[Kreyer]

I like the split curing of the LC base. I think I'm yet to find the right brand and ideal thickness though to prevent small dimensional errors from occuring.
The changes can be simply lifting in the palate, or a general contraction from curing. Sometimes everything's fine and sometimes there are irritating changes. What's your preferred brand?
IMO it's not as stable as I'd like it to be. The texture and taste is something that patients sometimes comment on but I don't see a problem there - it's just something quite different to their dentures.
Shellac is surely something from the ark, but there are brands that are useful.
I'm always trying to find ideal/best solutions for the different situations we're faced with. We don't have a "ones size fits all" answer to what we do, so that's where I'm coming from when asking for thoughts and opinions based on folk's experiences in their lab life. Even if I don't pick up any hints, there may be somebody else looking at this board who'll find an answer to a problem.

I use either a processed base or VLC Ultra-Tray from Candulor..


Candulor Dental -Ultra Tray

 

[araucaria]

Thermoformed baseplates - opinions............... popcorn


l thickness, cooling protocol, extensions, limitations, etc

 

[droberts]

Thermo-form .100 Surgical guide material.
I happen to use thermo-form 100% of the time on all conventional and implant locator dentures.

Clear, hardly any palatal lift at all leaving a uniform thickness.

I do not use it on any bar related cases, I then use a hard clear acrylic base with a imp coping to stabilize.

 

[droberts]

I use either a processed base or VLC Ultra-Tray from Candulor..


Candulor Dental -Ultra Tray

Congrats to your new occupation Rob

 

[CYNOSURER]

I use thermoform on most of mine. Most are .100 some .080. I block out with hand-itak. Wherever I use block out I cut out a window and replace with wax..... usually all the crest of the ridge and the some of the labial aspect. Processed base are great if vertical is not a problem. I hate the VLC I get from offices. Too brittle. Most people use too much block out so that they don't break the model which also can make it an unstablilized base.

 

[AJEL]

The VLC was a choice until I developed an allergy to the stuff, & as it is super rigid going over undercuts requires big blockout, or when it flexed it cracked. I go through the trouble of duplicating the master model with minor blockout, postdam & process a flexing stable baseplate using vynacron vynapac. The material can be trimmed to .3mm over the ridges (can help in set-up) and doesn't crack, it flexes in the flange area but is stable in the palate & with the postdam in to check suction during wax try-in. If over ERA, Spherio, Locator I can process the attachment & recover it later. I have even used this over Hader bars. With immediates these allow setting teeth for a try-in. Kcdt I to am surprised that shellac is still produced when I started we would use baby powder to keep the stuff from sticking but U still burnt YR fingers.

 

[AJEL]

Am I the only one who still uses the swissedent (papillameter, almeter, rim former? or occlusion balancers? or the Homedicia setup plate?Im just wondering.

 

[JohnWilson]

Nope not the only one

 

[kcdt]

ditto

 

[rkm rdt]

I still roll my own wax rims...by cracky!

 

[Jerr57]

I still roll my own wax rims...by cracky!

Much better than the "bought" ones that tend to be too big and too stiff..."by cracky"????

 

[HDL Owner]

process bases I find are best but master model is gone,also,you get a reduction in space needed for tooth placement regardless of how thin you make them. Time consuming? not, a sheet of BP wax heated and adapted of off for processing. cost to Dr=20$ with rim attached. Cheap? not compared to slipping baseplates and new impression to pour.

 

[JohnWilson]

If you are charging $20 for a processed base and wax rim you need to rethink the market you are after. I am proud of you for wanting to do better quality work but you have to charge for the service or they will not value the extra effort.

We charge $145 for a processed base/bite rim.

 

[stevo]

Printed resin bases

Quote:The one thing I've yet to try is to have a model scanned and a resin pattern printed - surely it can't get better than that?

Has anyone try this technique that was suggested
Would love to hear if it was successful, can't see why it wouldn't be as you can try printed resin partial frames in before casting.

Cost would be the prohibiting factory

 

[HDL Owner]

Holly @#$% 145? I would get tared and feathered by everyone of my Dr's. I make this cheap and available base to encourage them to use this and take a reline imprssion inside after try-in to get better boarder contours and fit.

 

[droberts]

You may want to consider " A change". You can fabricate a much better prosthesis if you have it completely waxed ready for processing. Starting with an excellent impression, try-in fully waxed to full contours / anatomy, thickness, etc.
When a set up as such comes back from the doctor ready for processing, it is checked for occlusion, sealed to the cast, borders of the cast cut back to the edge of the wax, and then invested. This provides you with a denture with minimal finishing. If a doctor is going to take a wash impression, have them do it at the bite rim stage. That way you can do the protocol mentioned above, save time and make more money
As for a processed base, $90.00, if needed it is waxed to the cast then injected,
(Ivocap). Maybe do two or so a year. The rest are all Vac using the .100 Surgical guide material.

 

[HDL Owner]

Miss spoke--yes impression AFTER wax try-in to contours and patient final approval. Other wise, new impression will be compromised with furture try-in and abrassions from a baseplate. Thanks droberts for pointing this mistake out to me! While at it here? why do Dr's say: Post Dam and finish?" No post dam and a very loose fitting denture. I place a post seal and perephrial seal on all Max/mand dentures. As for finish-no sending it back directly from mold-YOU finish it!!!!