Stent overload?

[Henry O]

I have a concern.
My upper yaw teeth have been extracted in preparation for implants.
Dentist wanted to support new dentures with only two stents.
I suggested at least four implants. Dentist agreed but then she drilled three holes.
All three holes are in front close to each other, none in the back.
Besides the limited load distribution problem, my main concern is the torque on the stents.
If my molars bite on something hard, cantilever action with about 30 to 40 mm lever arm causes high torque at the point of the stents. I am afraid, this could break the yaw bone.
Is there a reason not to put two stents in the back close to the molars to eliminate the problem?
Please advise - Thanks

 

[Dr M]

Good day

Is there enough bone present posteriorly? Sometimes the availability of sound bone as well as the proximity to other vital structures can influence the decision to position implants.

 

[Henry O]

Dentist mentioned something about not enough bone.
But, will it break???

 

[honestdoc]

Where did you get the implants placed? Did a surgeon or general dentist place it? The upper posterior bone usually is thinner under the sinus cavity. Usually the surgeon may recommend lifting the sinus to allow more bone grafting to place implants. Without posterior implants, your denture may not be as stable and retentive.

With the cantilever action, most likely your bone won't break but it won't osteointegrate (heal) around the implants causing the implants to be loose and fail. I always recommend an experienced surgical team as well as restorative team for implants.

 

[Henry O]

It was a general Dentist. So far, only holes are drilled, no implants yet.
Healing ... that's another point, the bone integration might suffer due to constant wiggle.

 

[Dr M]

I agree with honestdoc.
Usually a surgical team with proper planning is needed.
It is also strange that the dentist only drilled holes without at least placing the implant screws. Usually this is done and then they are covered by healing abutments if immediate loading was not planned, in order to allow osseo-intergration to take place.
This does sound like a strange protocol to me.
As honestdoc said, if the implants aren't positioned properly to allow for the various forces that are going to influence them, the implants will ultimately become loose and then fail.
It sounds like the general dentist might have realised that the positioning was not planned properly and then aborted placing the implants.
I would consider getting the procedure done by someone that is experienced in implant placement as well as the subsequent restoration.
After all-you are paying a lot of $.

 

[Henry O]

I could be wrong about the sockets. Maybe they have been placed. But they are not visible.
In the lower yaw I got two implants at the same time, there the metal (stents) is visible.

I was thinking, if the denture would be on a ball joint or stents that are slightly flexible in the
forward-backward plane, the problem might be reduced or eliminated.

 

[Henry O]

Update:

The sockets were placed. They were not visible in the mouth with a mirror, but X-ray showed them.
Dentist acknowledged my concern with cantilever torque but showed 3D X-ray that there is very little bone under a big sinus cavity.

Can the bone mass be increased?

 

[honestdoc]

Sinus lift surgery usually done by oral surgeon or periodontist.

 

[Dr M]

Yes, sinus lift surgery with or without additional bone augmentation, but this does increase the overall treatment time.