Vaccuum !!

Edy

Edy

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I am trying almost everything with an old good friend after i made for him a new upper denture , nothing is improving even after i took an impregum impression on the new denture and did the post dam area very carefully again .. the denture sits very good but when he opens a bit his mouth it falls down , i am thinking on retaking another impregum impression but this time not touching the post dam area and leave it like that .... hmmmm what you can suggest to check ? i chekced all the borders of the denture too to see if they are high and may push the denture down , but nope , all is ok there too .. i am out of ideas but i cant leave this case , dont get me wrong , i do like 3-4 dentures per month with upper vaccums and most of them are very good , on this particular case i just cant see whats wrong @_@ , he has good retention gingivals and all seems ok on his side , in this case its better to redo the hole denture ? or keep try filling it a bit after an impregum impression ? uff!
 
M

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I would try a functional impression technique using hydro-cast,lynol or the equivalent. The material will mold to his mouth while he is wearing the denture you will also be able to see if there are any over extentions that need to be relieved. When he is happy with fit and function then just reline the denture.
 
Edy

Edy

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hehe , i forgot to mention the i did that too today with him , i got soft-liner cast , after that the denture kept falling so i just took it out of denture and left it like that for now , told him to put a bit of denture glue :S , and said to him to go with the denture glue for a few days it may "sit better with time " lol , but ofcourse i told him to come back to me after a few days for another impregum impression .
 
M

MasterCeramist

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Did he have this issue with his old denture ?
 
Jo Chen

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Reduce the border width in the hemular notch area
 
B

bill m

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My old time drs. would green stick a post dam and see if they got better retention. If that happens you can now do a reline leaving the green stick in place , telling the lab not scrape the postdam in the model. It does sound like the border is too long somewhere or the a frenum needs to be relieved.
 
P

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F/- dislodgement can be due to insufficient resistance or retention. Most general dentists think that retention is the most important factor but like in C&B, resistance is infinitely more important than retention. Resistance depends on primary and secondary support areas e.g. palate, tuberosity vestibule etc. Good resistance requires good extension without under- or OVER-EXTENSION. On the other hand, retention depends on your posterior seal e.g. post dam.

I can write a 3 hr essay on this. I will try and keep it brief. I have rated this in order of likelihood.

Assuming impression and acrylic processing is accurate, when the patient opens his/her mouth and denture dislodges. It can be due to,

1.) over-extension in the vestibular areas or over-extension posteriorly more than hard/soft palate junction, more than the palatine fovea and the 'vibrating line'. The way to check it is with a) GC Fitchecker which is a snap set PVS material or b) pressure indicating paste (PIP). With it only needs a very thin layer on all the fitting surface and flanges. While material is setting, you need to muscle trim. Check the labial as well as the 2 buccal frenal attachments. Most of the time, the high attachments dislodges F/-. When the material sets you can visualize along the flanges where the thin PVS material is which indicates over-extension. Thin layer of PVS on the fitting surface indicates inaccuracy - needs adjustment of only those high areas. By enlarge, most problems derive from over-extension. Under-extension of the palate can be a cause but unlikely. I will check it though.

2) very mobile alveolar mucosa in anterior maxilla as a result of significant ridge resorption when patient is edentulous in the maximal but has retained mandibular anterior teeth e.g. combination syndrome. When patient is functioning e.g. occlusal contact -> distortion of soft tissue followed by mouth opens leads to rebound -> dislodge of denture base. If this is the case, your impression technique was incorrect. Requires a retake impression of either a combination of muco-compressive and mucostatic approach or just mucostatic approach. Otherwise, if you want to salvage the newly fabricated F/-, can try to hollow out acrylic where mobile tissue is and do a functional reline impression for 2 days and ask pt to return to perform a cold-cure acrylic reline

3) Insufficient palatal seal. Using fit-checker can help you to visual this. If there is a thick layer of material when you load the F/- in the primary support area e.g. continuous thumb pressure on palate when material is setting and there is a thick layer of PVS material after it has set. You can bet you that the posterior seal is poor, need to score more post dam on the cast before processing or otherwise, reline with green or brown stick.

Hope this helps. Removable Prosthodontics is a lost art that most general dentists do poorly. Without it, they also do not understand the intricacies of tooth positions relating to full-mouth rehabilitation of teeth and/or implants.

Happy to answer other material science and clinical questions from a Prosthodontics Resident's perspective (Board certified, awaiting thesis submission)
 
G

grantoz

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Basically what the prosthodontist said .I can also write a 3 hr essay on the paper as well you can probably also. Im just a denturist also . I would start again take functional impressions check your extensions and check if your friend has a flabby ridge I have found that these are the 2 main reasons uppers drop. Im sure you know about postdam etc as you have been doing this for a while . If they have a flabby ridge try a double impression technique compress the stable mucosa and relieve the unstable ridge area.
 
Edy

Edy

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Thank you guys but unfortunatly i could not understand the long explination by prosthodontic :(
My enlish is very simple and those dental terms even worst for me , cant get what they mean like under/over extention or vibrating line and most of these words are unfamiliar to me , i thank you thow for help.
And bill m , what you mean gren stick? Doc used a green wax to put in post dam area to check for a better fit?
 
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bill m

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The doctor would melt green compound where he wanted the post dam check for suction and if he was satisfied he would do a rubber base for a reline. Wherever he thought the borders were short he would add compound prior to taking the impression. Maybe there are better ways to do this but I know it worked for him. He would do this when he thought the postdam could be improved.
 

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