tissue displacement

[kcdt]

What happens when you do a normal impression on soft tissue is that the tissue folds over on itself and distorts...When it comes to fit the final denture, it may fall out due to the pressure the compressed tissue exerts on it. Selective loading works somewhat but only if you drill some relief holes in the impression tray. Far better to do an open tray....But this is a totally foreseeable thing...During a proper prosthetic examination one of the things to check for is flabby tissue on the ridge crest...Exactly the scenario crops up like that when a patient doesn't get a reline for years and then expects a miracle.....For the very reason that you folks mention, relining that type of tissue is problematic in that the front teeth are in the way of the opening needed to do an open tray impression....Alternatively if there is enough room in the denture it would need to be grossly hollowed out and do a selective load reline impression...but yes you folks are right. It is a clinical problem....not necessarily a lab problem...I have had one of those cases recently and placed a Luckman dam across the back of the denture and as well advised the patient from the getgo that I would only try a reline....because they told me they needed a reline which I usually tell patients that I can only do after a full assessment...In my case I already told the patient that relining is only an attempt to correct the problem and may not actually correct the problem....So when I told her it would be $2800 to do a remake she was willing to forgo a bit of discomfort...ON that case selective load was impossible because there was not enough acrylic left to make an open tray or do a selective load impression because they usually require 2-3 mm of relief or an open tray.....a bit more than acrylic that was there...Massad covers these in his videos quite well.

It's all about exam and diagnosis. If they don't even bother to look how can they reasonably expect to treat. It boggles the mind...

 

[denturist-student]

ive already thrown that caveat out there. i hold zero responsibility for this case at this stage.
as mentioned above, this IS the treatment planning stage. no one is moving forward without a clear path of expectations. this IS the initial visit(s) from the patient to the dr and we are determining what options are available for presentation of treatment. implants are out, as she was referred for that already. she is not a candidate. her original denture is god only knows how old (approx 20yr) and not mine, nor the treating dr at this time.
we are exploring options, and since i know less than an adequate amount for this type of situation, i brought it here for feedback. dr is also consulting some options on the surgery side of things.

I might treatment plan something like this.....1 Preliminary impressions use injected alginates in two stages and take a rough bite with intraoral putty after sawing off the handles and take a tongue depressor and measure the resting and occluding bites so you can adjust the articulator when you make your rims ( dentist can place some cursory markings on the putty)., 2 Secondary impressions on a bite registration rim with the upper six anteriors set up. Called an esthetic try in...(dentist can reposition them at his will factoring in phonetic and esthetic considerstaions),redo the bite registration here a pin tracer and facebow can be easily incorporated.and take about 5 extra minutes to do......3 Full try in with a final impression using light body wash, If they have poor ridges, then use Ivoclar or Candulour Lingoform teeth against a flat tooth such as Bioform or Ivoclar 0 degree setup on a compensating curve (set lowers first either on the ridge or as per neutral zone impressions if they exist). Return to lab for preliminary processing....4 Use a reline jig to keep the occlusion intact but make an impression of intaglio surface of denture using stone or putty on the reline jig and then hollow out the intaglio surface of the denture by about 1-2 mm, do this for both upper and lower dentures.....5 Use either Tempo, COEsoft, or Hydrocast ( with a microseal base) to reline temporarily in the clinic using the reline jig for the patient to wear for 2-5 days......You will be amazed at the quality of the reline impressions you get using the reline jig......without using the reline jig you may lose the bite you worked hard to obtain originally....Process the reline and insert....
It takes a few extra steps but it can allow for some margin for errors and each step gets progressively refined...
There is soooo much to do clinically though and unfortunately few dentists have the time to dedicate to precision and steps cannot be missed.
Massads technique goes a bit beyond this by using a neutral zone and external impressions....Turbyfills actually uses the phonetic placement of the upper anterior teeth and then he fabricates an upper denture against a processed bite rim and looks for lingualized points as well as he uses hydrocast for a functional impression material.....
I have used both methods which have different properties and results successfully....I have also adapted both of those concepts into my own protocol but few in my patient base cannot tolerate so much work so I occasionally use the existing dentures as an informal bite registration and impression tray....but that has its disadvantages too.
Anyways take care and keep well....once a student always a student