1or 2 peaces splint over lower jaw

Adi

Adi

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Hi

I'm seeing a lot of one peace full arch prosthesis over lower jaw implants, shouldn't it be split to two peaces to allow for jaw movement during chewing?
 
JMN

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Hi

I'm seeing a lot of one peace full arch prosthesis over lower jaw implants, shouldn't it be split to two peaces to allow for jaw movement during chewing?

Competing philosophy is that the one piece construction helps give strength as most people getting 4+ implants and a prosthesis on mua or whatever will usually have ridge height reduction to allow sufficient room for all the parts and the teeth.
 
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Kiper Lee

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I don't think you want cantilever pontic over hybrid implant bridge, which more likely occurs to separate bridges.
 
Adi

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Bone flrxing
A research paragraph :
As some studies [10, 11] have reported that the framework can counteract mandibular flexure, this matter could be a subject for discussion. While the use of sectional prosthesis designs in 2- or 3-piece superstructures through the symphysis region has been suggested to minimize the effect of mandibular flexure and peri-implant bone stress [10, 12–14], other studies have found smaller stress values for 1-piece superstructures compared to sectioned ones.
 
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Bone flrxing
Abstract
The mandible has a property to flex inwards around the mandibular symphysis with change in shape and decrease in mandibular arch width during opening and protrusion of the mandible. The mandibular deformation may range from a few micrometres to more than 1 mm. The movement occurs because of the contraction of lateral pterygoid muscles that pulls mandibular condyles medially and causes a sagittal movement of the posterior segments. This movement of mandible can have a profound influence on prognosis and treatment outcome for various restorative, endodontics, fixed, removable and implant-related prosthesis. The review unfolds the causes, importance and clinical implications of median mandibular flexure in oral rehabilitation. This review also highlights the appropriate preventive measures and techniques that should be adopted by clinicians to minimise the effect of flexural movement of the jaw during oral rehabilitation. This would not only help clinicians to achieve a good prosthesis with accurate fit and longevity but also maintain the health of the surrounding periodontal or periimplant gingival tissues and bone.

Keywords: cross-arch prosthesis; implants; mandible; mandibular flexure; mandibular jaw movements; muscles of mastication.

© 2015 John Wiley & Sons
Ltd.

 
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So you're saying it's acceptable?
What about the jaw movement?
Wow, that's really insightful, thanks for sharing this.
Well, as you can see in the conclusion, one piece bridge has smaller stress values. I guess it also suggests the bridge has a lower chance of break/crack, less advantage in minimizing the effect of mandibular flexure and peri-implant bone stress though.
In other points of view, more sections of framework means more implant surgery, more strictly oral condition, exorbitant price.
I haven't had much experience (precisely 8 yrs) in the dental industry, I'm considered as a newbie compared to most of people in this forum, but in my career path, I only have seen one divide all on X implant bridge, from #22-24, #25-27(An Israel client),and no cantilever pontic.
Here is the implant bridge I'm currently working on, just for your reference.
6Egcb3VzsoTDnP7.jpg
 
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Kiper Lee

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o_OOh, sorry my bad, I suddenly realize we are talking about mandibular jaw movement and framework stress values.
I suppise the upper frame won't help this situation. Please ignore it, my bad, don't know how to recall the comment.
 
JohnWilson

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Mandible flexure is real, but is a small reason why there are complications in full arch implant restorations.

Most of the complications I see are based upon restorations that were surgically driven rather than prosthetically driven. Poor planning is the reason why things fail most often. The materials we are using today are brutally strong. However if passivity is not achieved no matter how strong the material is you will have complications.

Now take it one step further, the type of restoration will have larger windows of success, meaning if I am doing a standard FP1 roundhouse my joints to the restorations even on the most perfectly planned surgical outcome will be much much less than a poorly planned FP3. Even if I have ups and downs to the bone if the volume of the material is 3 times the joint diameter of my PERFECTLY planned FP1 we will likely have success and overcome any flexing of the jaw.

Like all things in dentistry we are looking for the LARGEST window of success with the hopes we can offset the known challenges ALL cases will have. With every choice we make there is a tradeoff, wisdom is what allows us to make the better choices but we are never foolproof in our paths.
 
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Now take it one step further, the type of restoration will have larger windows of success, meaning if I am doing a standard FP1 roundhouse my joints to the restorations even on the most perfectly planned surgical outcome will be much much less than a poorly planned FP3. Even if I have ups and downs to the bone if the volume of the material is 3 times the joint diameter of my PERFECTLY planned FP1 we will likely have success and overcome any flexing of the jaw.
What's FP1 and FP3?
 
Brett Hansen CDT

Brett Hansen CDT

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Mandible flexure is real, but is a small reason why there are complications in full arch implant restorations.

Most of the complications I see are based upon restorations that were surgically driven rather than prosthetically driven. Poor planning is the reason why things fail most often. The materials we are using today are brutally strong. However if passivity is not achieved no matter how strong the material is you will have complications.

Now take it one step further, the type of restoration will have larger windows of success, meaning if I am doing a standard FP1 roundhouse my joints to the restorations even on the most perfectly planned surgical outcome will be much much less than a poorly planned FP3. Even if I have ups and downs to the bone if the volume of the material is 3 times the joint diameter of my PERFECTLY planned FP1 we will likely have success and overcome any flexing of the jaw.

Like all things in dentistry we are looking for the LARGEST window of success with the hopes we can offset the known challenges ALL cases will have. With every choice we make there is a tradeoff, wisdom is what allows us to make the better choices but we are never foolproof in our paths.
Great seeing your posts more frequently here again John. This is great information. Thank you
 
Adi

Adi

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Mandible flexure is real, but is a small reason why there are complications in full arch implant restorations.
If so , is it acceptable to make it one peace ? I'm asking the same question again to make sure I'm getting it right.
I have a case i'm working on , I keep telling myself it's better to make it one peace , especially this kind of a case because the vertical dimension is so high , thus it's going to need all the support we can give for the stability of the frame. 2021-11-23_00010-001_DentalCadScreenshot.png 2021-11-23_00010-001_DentalCadScreenshot2.png 2021-11-23_00010-001_DentalCadScreenshot3.png
 
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JMN

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If so , is it acceptable to make it one peace ? I'm asking the same question again to make sure I'm getting it right.
I have a case i'm working on , I keep telling myself it's better to make it one peace , especially this kind of a case because the vertical dimension is so high , thus it's going to need all the support we can give for the stability of the frame. View attachment 39848 View attachment 39849 View attachment 39850
Yeah, it's perfectly fine.

What you're picking at is about a 1% chance of anything even noticeable, and no real world increased risk of failure that's measurable and can be attributed to this.

There are larger percentages to worry about of actual failure causing problems. But I love that you are looking at things that closely.
 
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Thank you all for the information 🙂
Please be kind to check the attached files and see if there are any recommendations ,
I designed the custom abutments and the restoration .

some of abutment margins were extended as open as possible to allow the dentist to remove the excess cement , my main thought was The margin is a part of the restoration, so why not extend it as open as i can .
Some buccal margins were designed in a way to make easy for the patient to clean since it's above gingiva .

Some were just above gingiva so I couldn't do anything about it .

I'm planning to laser print the frame..
 

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