Failing Lower Bridge: Treatment Recommedations?

First manage his periodontal disease, then restore his IC to an optimal plane, then ridge augmentation, and then consider implants

WOW that is one YUGE cantilever on the right. The occlusal plane is way off and this case both arches need to be treated to get an acceptable outcome that will last long term. I would consider section the bridge between 18-19 and extract 19 and all teeth to the right. then place 4 implants with one tilted anterior to the right mental foramen and restore that with a hybrid. (better if he will go for edentulating the entire mandible. In the upper arch treat the perio then either implants in UL and a fixed bridge on them or a partial denture

In Lower jaw, I would removed all teeth but 36,37,38 and the bridge. Put single crowns on 36,37,38. 4x intraforamal implants + hybrid or fixed bridge up to 46(canteliver 46) Upper jaw first perio then sinus lift+2x implant/crowns

Those radiopaque findings in the posterior mandible will be for sure parotide Sialolithiasis or tonsilloliths but should look into it just to be sure. Ridge augmentation in the lower right in a simple answer is NO. The treatment plan previously mentioned is the most correct one: lower All-on-4 + upper 2 implants + sinus lift after perio tx

All on four top and bottom work with a oral surgeon and prosthodontist. This case is grossly mismanaged and the patient deserves a break. Don't worry about the sialoliths, common finding on X-ray, assymptomatic. Good oral hygiene and maintenance of implants long term,I normally I don't like all on fours but this case is too far gone. I have a similar case pending, unfortunately patients are vulnerable to who chooses to treat them. I look for the bone architecture presented in deciding you will be chasing the lost bone on the right, this should have been grafted at the get go, an example of long term cantilever damage and what not to do.

Remove the lower bridge first and then make focused X ray of the rest of the teeth to evaluate the real bone/periodontal situation. If lower molars are OK, cover them by crowns. It’s a posterior bite collapse case here, and I would suggest making transitional upper and lower dentures to establish correct occlusion and cosmetic parameters. Only after that you can discuss an implant treatment plan.