Do you place a post-palatal seal for upper dentures when heat injecting acrylic?

[Denturepropgh]

I like to wax them in place on the impression before pouring if the doctor takes a wash for processing.

As someone who processes using the above method, my jaw dropped when I read this in the the Air Force Manual, where everytime I peruse, I learn something new!

7.101.1.2. Create a posterior palatal seal as follows:

7.101.1.2.1. A posterior palatal seal is a feature incorporated into a maxillary denture to offset denture processing changes in the acrylic and improve denture retention. (NOTE: This seal is not recommended for the positive-pressure, injection-molded technique SR Ivocap®.) In processing, the denture acrylic shrinks away from the cast slightly. This shrinkage is most obvious along the posterior border of the maxillary denture. If compensation is not made for this distortion, the posterior border of the denture will not touch the patient’s tissue when the denture is placed in the mouth. As a result, air enters between the denture base and the mouth tissues, and the denture falls away from the patient’s ridge and the palate.

-pg 283 of the Basic Sciences, Removable Prosthodontics, and Orthodontics. Air Force Pamphlet 47-103 Volume 1 November 15 2005.

I couldn't believe my eyes, and everybody I've mentioned it to express their unwavering support of placing a post-dam no matter what. I want to try. Sounds like less work, better results to me. If it's in the Air Force Manual, you know it's legit.

 

[sidesh0wb0b]

I like to wax them in place on the impression before pouring if the doctor takes a wash for processing.

As someone who processes using the above method, my jaw dropped when I read this in the the Air Force Manual, where everytime I peruse, I learn something new!

7.101.1.2. Create a posterior palatal seal as follows:

7.101.1.2.1. A posterior palatal seal is a feature incorporated into a maxillary denture to offset denture processing changes in the acrylic and improve denture retention. (NOTE: This seal is not recommended for the positive-pressure, injection-molded technique SR Ivocap®.) In processing, the denture acrylic shrinks away from the cast slightly. This shrinkage is most obvious along the posterior border of the maxillary denture. If compensation is not made for this distortion, the posterior border of the denture will not touch the patient’s tissue when the denture is placed in the mouth. As a result, air enters between the denture base and the mouth tissues, and the denture falls away from the patient’s ridge and the palate.

-pg 283 of the Basic Sciences, Removable Prosthodontics, and Orthodontics. Air Force Pamphlet 47-103 Volume 1 November 15 2005.

I couldn't believe my eyes, and everybody I've mentioned it to express their unwavering support of placing a post-dam no matter what. I want to try. Sounds like less work, better results to me. If it's in the Air Force Manual, you know it's legit.

i have heard this before. probably from reading the AF manual previously....though we still add a post palatal seal (and we inject). no complaints about it, dentures seat just fine and everyone is happy!

 

[CanadaDenturist]

Denturist of over 20 years here. I've used different injection systems over the years as well as traditional packing. I've done all systems with and without post palatal seals. I've always achieved a better fit when using a post palatal seal.

If using the Ivocap or Ivobase system you will not end up with better results by not doing one. Worst case is you'll end up with similar results by not placing one, but not better. As I've said though, my real world experience has been that a post palatal seal will improve the fit. I absolutely disagree with the US military here.

 

[JKraver]

I use a palatal seal with ivobase, better more reliable results.

 

[Doris A]

WE use Ivocap, always post palatal seal.

 

[FASTFNGR]

I do not understand what is the relationship here between technique and material. One has nothing to do with the other. Palatal seal is a must in my opinion regardless of the method.

 

[JKraver]

I do not understand what is the relationship here between technique and material. One has nothing to do with the other. Palatal seal is a must in my opinion regardless of the method.

Ok, so the palatal seal serves two functions to compensate for the 7% acrylic shrinkage of traditionally compression packed dentures. It also forms a small pressure barrier that keeps air and liquids from back washing and dislodging the denture.

Continually injected denture acrylics such as ivocap/base have very near 0% shrinkage due to the material being pushed in while it is curing. This covers the first reason why a palatal seal is needed, but not the second. There does not need to be as deep palatal seal with ivocap/base.

 

[Flipperlady]

Yes I would place a post palatal seal on any denture. The impression/scan is a snapshot in time of the tissue which can change for many reasons like being dehydrated etc... the seal gives the denture a bit more help even assuming the injected denture fits perfectly..
Edit: The seal is at the dentists discretion of course and some the patient can't tolerate...

 

[JonnyLathe]

I inject with ivobase and still put on a post-palatal-seal. Just draw where I want it (or hopefully see it on the cast) and carve it out by hand with a wax carver. I prefer that to a hand piece because I feel like I can control it better. I get that theoretically you could go without it when injecting but that's also assuming the impression is near perfect.

 

[Doris A]

I inject with ivobase and still put on a post-palatal-seal. Just draw where I want it (or hopefully see it on the cast) and carve it out by hand with a wax carver. I prefer that to a hand piece because I feel like I can control it better. I get that theoretically you could go without it when injecting but that's also assuming the impression is near perfect.

I use this for my post dams. Although they have increased the price alot.

Post Dam Carver

The Post Dam Carver carves the 2mm post dam bead at the vibrating line and feathers the denture cast in the customary butterfly shape.

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