Lower Full arch Multiunit level implant restoration?

Cases and Questions
1

In a lower full arch implant restoration at Multiunit level, is it necessary to split the prosthesis to circumvent Mandibular flexure?
If so, is the smaller segment stable at a multiunit screw retained level?
If not necessary, any particular occlusal considerations to follow?

2

Having seen that concern with subperiosteal implants, I am surprised that it isn’t currently commented about. I’ve done a number of cases with first molar to first molar implants with no symptoms. I don’t use MUA;s for anything but full arch cases. I suspect the added component adds a bit of flex to the system and hence the lack of jaw flexure problems.
The key part about occlusal scheme, is to have vertical forces wherever feasible.

3

It could be a problem if implants are posterior to the mental foramen. I’ve had one case where the patient had discomfort with max opening. Clenching also cause flexure and thus could cause pain but my patient didn’t have that issue. I sectioned the provisional restoration distal to the canine and symptoms subsided. No issues with any other cases.

4

Thanks for your reply. @3d_dental_lab What about the final prosthesis? The segment distal to the canine doesn’t have the advantage of cross arch stabilisation. Have you encountered screw loosening in that case?

6

The case I mentioned above was at the end of wearing a provisional so not an issue with them but if the issue arose immediately after surgery I would simply disconnect the distal most implant and let it heal with a temp healing abutment. My provisional would end at the last implant forward of that one so cross arch stabilization would still be in effect. The definitive restoration would be made in 2 pieces. Hope that answers your question.

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7

Carl Misch said that single split anywhere in the arch interforaminaly can do the trick relieving rigidity and complying to mandibular flexure. Stefan Ihde (using bicortical implants) thinks that using, whenever possible, distalmost abutments in second molar region and composite to metal prosthesis give enough elasticity to comply to mandibular flexure.